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#endif 193 194/* 195** CAPI3REF: Test To See If The Library Is Threadsafe 196** 197** ^The sqlite3_threadsafe() function returns zero if and only if 198** SQLite was compiled with mutexing code omitted due to the 199** [SQLITE_THREADSAFE] compile-time option being set to 0. 200** 201** SQLite can be compiled with or without mutexes. When 202** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 203** are enabled and SQLite is threadsafe. When the 204** [SQLITE_THREADSAFE] macro is 0, 205** the mutexes are omitted. Without the mutexes, it is not safe 206** to use SQLite concurrently from more than one thread. 207** 208** Enabling mutexes incurs a measurable performance penalty. 209** So if speed is of utmost importance, it makes sense to disable 210** the mutexes. But for maximum safety, mutexes should be enabled. 211** ^The default behavior is for mutexes to be enabled. 212** 213** This interface can be used by an application to make sure that the 214** version of SQLite that it is linking against was compiled with 215** the desired setting of the [SQLITE_THREADSAFE] macro. 216** 217** This interface only reports on the compile-time mutex setting 218** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 219** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 220** can be fully or partially disabled using a call to [sqlite3_config()] 221** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 222** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 223** sqlite3_threadsafe() function shows only the compile-time setting of 224** thread safety, not any run-time changes to that setting made by 225** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 226** is unchanged by calls to sqlite3_config().)^ 227** 228** See the [threading mode] documentation for additional information. 229*/ 230int sqlite3_threadsafe(void); 231 232/* 233** CAPI3REF: Database Connection Handle 234** KEYWORDS: {database connection} {database connections} 235** 236** Each open SQLite database is represented by a pointer to an instance of 237** the opaque structure named "sqlite3". It is useful to think of an sqlite3 238** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 239** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 240** and [sqlite3_close_v2()] are its destructors. There are many other 241** interfaces (such as 242** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 243** [sqlite3_busy_timeout()] to name but three) that are methods on an 244** sqlite3 object. 245*/ 246typedef struct sqlite3 sqlite3; 247 248/* 249** CAPI3REF: 64-Bit Integer Types 250** KEYWORDS: sqlite_int64 sqlite_uint64 251** 252** Because there is no cross-platform way to specify 64-bit integer types 253** SQLite includes typedefs for 64-bit signed and unsigned integers. 254** 255** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 256** The sqlite_int64 and sqlite_uint64 types are supported for backwards 257** compatibility only. 258** 259** ^The sqlite3_int64 and sqlite_int64 types can store integer values 260** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 261** sqlite3_uint64 and sqlite_uint64 types can store integer values 262** between 0 and +18446744073709551615 inclusive. 263*/ 264#ifdef SQLITE_INT64_TYPE 265 typedef SQLITE_INT64_TYPE sqlite_int64; 266# ifdef SQLITE_UINT64_TYPE 267 typedef SQLITE_UINT64_TYPE sqlite_uint64; 268# else 269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 270# endif 271#elif defined(_MSC_VER) || defined(__BORLANDC__) 272 typedef __int64 sqlite_int64; 273 typedef unsigned __int64 sqlite_uint64; 274#else 275 typedef long long int sqlite_int64; 276 typedef unsigned long long int sqlite_uint64; 277#endif 278typedef sqlite_int64 sqlite3_int64; 279typedef sqlite_uint64 sqlite3_uint64; 280 281/* 282** If compiling for a processor that lacks floating point support, 283** substitute integer for floating-point. 284*/ 285#ifdef SQLITE_OMIT_FLOATING_POINT 286# define double sqlite3_int64 287#endif 288 289/* 290** CAPI3REF: Closing A Database Connection 291** DESTRUCTOR: sqlite3 292** 293** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 294** for the [sqlite3] object. 295** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 296** the [sqlite3] object is successfully destroyed and all associated 297** resources are deallocated. 298** 299** ^If the database connection is associated with unfinalized prepared 300** statements or unfinished sqlite3_backup objects then sqlite3_close() 301** will leave the database connection open and return [SQLITE_BUSY]. 302** ^If sqlite3_close_v2() is called with unfinalized prepared statements 303** and/or unfinished sqlite3_backups, then the database connection becomes 304** an unusable "zombie" which will automatically be deallocated when the 305** last prepared statement is finalized or the last sqlite3_backup is 306** finished. The sqlite3_close_v2() interface is intended for use with 307** host languages that are garbage collected, and where the order in which 308** destructors are called is arbitrary. 309** 310** Applications should [sqlite3_finalize | finalize] all [prepared statements], 311** [sqlite3_blob_close | close] all [BLOB handles], and 312** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 313** with the [sqlite3] object prior to attempting to close the object. ^If 314** sqlite3_close_v2() is called on a [database connection] that still has 315** outstanding [prepared statements], [BLOB handles], and/or 316** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 317** of resources is deferred until all [prepared statements], [BLOB handles], 318** and [sqlite3_backup] objects are also destroyed. 319** 320** ^If an [sqlite3] object is destroyed while a transaction is open, 321** the transaction is automatically rolled back. 322** 323** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 324** must be either a NULL 325** pointer or an [sqlite3] object pointer obtained 326** from [sqlite3_open()], [sqlite3_open16()], or 327** [sqlite3_open_v2()], and not previously closed. 328** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 329** argument is a harmless no-op. 330*/ 331int sqlite3_close(sqlite3*); 332int sqlite3_close_v2(sqlite3*); 333 334/* 335** The type for a callback function. 336** This is legacy and deprecated. It is included for historical 337** compatibility and is not documented. 338*/ 339typedef int (*sqlite3_callback)(void*,int,char**, char**); 340 341/* 342** CAPI3REF: One-Step Query Execution Interface 343** METHOD: sqlite3 344** 345** The sqlite3_exec() interface is a convenience wrapper around 346** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 347** that allows an application to run multiple statements of SQL 348** without having to use a lot of C code. 349** 350** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 351** semicolon-separate SQL statements passed into its 2nd argument, 352** in the context of the [database connection] passed in as its 1st 353** argument. ^If the callback function of the 3rd argument to 354** sqlite3_exec() is not NULL, then it is invoked for each result row 355** coming out of the evaluated SQL statements. ^The 4th argument to 356** sqlite3_exec() is relayed through to the 1st argument of each 357** callback invocation. ^If the callback pointer to sqlite3_exec() 358** is NULL, then no callback is ever invoked and result rows are 359** ignored. 360** 361** ^If an error occurs while evaluating the SQL statements passed into 362** sqlite3_exec(), then execution of the current statement stops and 363** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 364** is not NULL then any error message is written into memory obtained 365** from [sqlite3_malloc()] and passed back through the 5th parameter. 366** To avoid memory leaks, the application should invoke [sqlite3_free()] 367** on error message strings returned through the 5th parameter of 368** sqlite3_exec() after the error message string is no longer needed. 369** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 370** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 371** NULL before returning. 372** 373** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 374** routine returns SQLITE_ABORT without invoking the callback again and 375** without running any subsequent SQL statements. 376** 377** ^The 2nd argument to the sqlite3_exec() callback function is the 378** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 379** callback is an array of pointers to strings obtained as if from 380** [sqlite3_column_text()], one for each column. ^If an element of a 381** result row is NULL then the corresponding string pointer for the 382** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 383** sqlite3_exec() callback is an array of pointers to strings where each 384** entry represents the name of corresponding result column as obtained 385** from [sqlite3_column_name()]. 386** 387** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 388** to an empty string, or a pointer that contains only whitespace and/or 389** SQL comments, then no SQL statements are evaluated and the database 390** is not changed. 391** 392** Restrictions: 393** 394** <ul> 395** <li> The application must ensure that the 1st parameter to sqlite3_exec() 396** is a valid and open [database connection]. 397** <li> The application must not close the [database connection] specified by 398** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 399** <li> The application must not modify the SQL statement text passed into 400** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 401** </ul> 402*/ 403int sqlite3_exec( 404 sqlite3*, /* An open database */ 405 const char *sql, /* SQL to be evaluated */ 406 int (*callback)(void*,int,char**,char**), /* Callback function */ 407 void *, /* 1st argument to callback */ 408 char **errmsg /* Error msg written here */ 409); 410 411/* 412** CAPI3REF: Result Codes 413** KEYWORDS: {result code definitions} 414** 415** Many SQLite functions return an integer result code from the set shown 416** here in order to indicate success or failure. 417** 418** New error codes may be added in future versions of SQLite. 419** 420** See also: [extended result code definitions] 421*/ 422#define SQLITE_OK 0 /* Successful result */ 423/* beginning-of-error-codes */ 424#define SQLITE_ERROR 1 /* Generic error */ 425#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 426#define SQLITE_PERM 3 /* Access permission denied */ 427#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 428#define SQLITE_BUSY 5 /* The database file is locked */ 429#define SQLITE_LOCKED 6 /* A table in the database is locked */ 430#define SQLITE_NOMEM 7 /* A malloc() failed */ 431#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 432#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 433#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 434#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 435#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 436#define SQLITE_FULL 13 /* Insertion failed because database is full */ 437#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 438#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 439#define SQLITE_EMPTY 16 /* Internal use only */ 440#define SQLITE_SCHEMA 17 /* The database schema changed */ 441#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 442#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 443#define SQLITE_MISMATCH 20 /* Data type mismatch */ 444#define SQLITE_MISUSE 21 /* Library used incorrectly */ 445#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 446#define SQLITE_AUTH 23 /* Authorization denied */ 447#define SQLITE_FORMAT 24 /* Not used */ 448#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 449#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 450#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 451#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 452#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 453#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 454/* end-of-error-codes */ 455 456/* 457** CAPI3REF: Extended Result Codes 458** KEYWORDS: {extended result code definitions} 459** 460** In its default configuration, SQLite API routines return one of 30 integer 461** [result codes]. However, experience has shown that many of 462** these result codes are too coarse-grained. They do not provide as 463** much information about problems as programmers might like. In an effort to 464** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 465** and later) include 466** support for additional result codes that provide more detailed information 467** about errors. These [extended result codes] are enabled or disabled 468** on a per database connection basis using the 469** [sqlite3_extended_result_codes()] API. Or, the extended code for 470** the most recent error can be obtained using 471** [sqlite3_extended_errcode()]. 472*/ 473#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 474#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 475#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 476#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 477#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 478#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 479#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 480#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 481#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 482#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 483#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 484#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 485#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 486#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 487#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 488#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 489#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 490#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 491#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 492#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 493#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 494#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 495#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 496#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 497#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 498#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 499#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 500#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 501#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 502#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 503#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 504#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 505#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 506#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 507#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 508#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 509#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 510#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 511#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) 512#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 513#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 514#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 515#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 516#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 517#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 518#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 519#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 520#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 521#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 522#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 523#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 524#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 525#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 526#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 527#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 528#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 529#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 530#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 531#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 532#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 533#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 534 535/* 536** CAPI3REF: Flags For File Open Operations 537** 538** These bit values are intended for use in the 539** 3rd parameter to the [sqlite3_open_v2()] interface and 540** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 541*/ 542#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 543#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 544#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 545#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 546#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 547#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 548#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 549#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 550#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 551#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 552#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 553#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 554#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 555#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 556#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 557#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 558#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 559#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 560#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 562 563/* Reserved: 0x00F00000 */ 564 565/* 566** CAPI3REF: Device Characteristics 567** 568** The xDeviceCharacteristics method of the [sqlite3_io_methods] 569** object returns an integer which is a vector of these 570** bit values expressing I/O characteristics of the mass storage 571** device that holds the file that the [sqlite3_io_methods] 572** refers to. 573** 574** The SQLITE_IOCAP_ATOMIC property means that all writes of 575** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 576** mean that writes of blocks that are nnn bytes in size and 577** are aligned to an address which is an integer multiple of 578** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 579** that when data is appended to a file, the data is appended 580** first then the size of the file is extended, never the other 581** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 582** information is written to disk in the same order as calls 583** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 584** after reboot following a crash or power loss, the only bytes in a 585** file that were written at the application level might have changed 586** and that adjacent bytes, even bytes within the same sector are 587** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 588** flag indicates that a file cannot be deleted when open. The 589** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 590** read-only media and cannot be changed even by processes with 591** elevated privileges. 592** 593** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 594** filesystem supports doing multiple write operations atomically when those 595** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 596** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 597*/ 598#define SQLITE_IOCAP_ATOMIC 0x00000001 599#define SQLITE_IOCAP_ATOMIC512 0x00000002 600#define SQLITE_IOCAP_ATOMIC1K 0x00000004 601#define SQLITE_IOCAP_ATOMIC2K 0x00000008 602#define SQLITE_IOCAP_ATOMIC4K 0x00000010 603#define SQLITE_IOCAP_ATOMIC8K 0x00000020 604#define SQLITE_IOCAP_ATOMIC16K 0x00000040 605#define SQLITE_IOCAP_ATOMIC32K 0x00000080 606#define SQLITE_IOCAP_ATOMIC64K 0x00000100 607#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 608#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 609#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 610#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 611#define SQLITE_IOCAP_IMMUTABLE 0x00002000 612#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 613 614/* 615** CAPI3REF: File Locking Levels 616** 617** SQLite uses one of these integer values as the second 618** argument to calls it makes to the xLock() and xUnlock() methods 619** of an [sqlite3_io_methods] object. 620*/ 621#define SQLITE_LOCK_NONE 0 622#define SQLITE_LOCK_SHARED 1 623#define SQLITE_LOCK_RESERVED 2 624#define SQLITE_LOCK_PENDING 3 625#define SQLITE_LOCK_EXCLUSIVE 4 626 627/* 628** CAPI3REF: Synchronization Type Flags 629** 630** When SQLite invokes the xSync() method of an 631** [sqlite3_io_methods] object it uses a combination of 632** these integer values as the second argument. 633** 634** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 635** sync operation only needs to flush data to mass storage. Inode 636** information need not be flushed. If the lower four bits of the flag 637** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 638** If the lower four bits equal SQLITE_SYNC_FULL, that means 639** to use Mac OS X style fullsync instead of fsync(). 640** 641** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 642** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 643** settings. The [synchronous pragma] determines when calls to the 644** xSync VFS method occur and applies uniformly across all platforms. 645** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 646** energetic or rigorous or forceful the sync operations are and 647** only make a difference on Mac OSX for the default SQLite code. 648** (Third-party VFS implementations might also make the distinction 649** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 650** operating systems natively supported by SQLite, only Mac OSX 651** cares about the difference.) 652*/ 653#define SQLITE_SYNC_NORMAL 0x00002 654#define SQLITE_SYNC_FULL 0x00003 655#define SQLITE_SYNC_DATAONLY 0x00010 656 657/* 658** CAPI3REF: OS Interface Open File Handle 659** 660** An [sqlite3_file] object represents an open file in the 661** [sqlite3_vfs | OS interface layer]. Individual OS interface 662** implementations will 663** want to subclass this object by appending additional fields 664** for their own use. The pMethods entry is a pointer to an 665** [sqlite3_io_methods] object that defines methods for performing 666** I/O operations on the open file. 667*/ 668typedef struct sqlite3_file sqlite3_file; 669struct sqlite3_file { 670 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 671}; 672 673/* 674** CAPI3REF: OS Interface File Virtual Methods Object 675** 676** Every file opened by the [sqlite3_vfs.xOpen] method populates an 677** [sqlite3_file] object (or, more commonly, a subclass of the 678** [sqlite3_file] object) with a pointer to an instance of this object. 679** This object defines the methods used to perform various operations 680** against the open file represented by the [sqlite3_file] object. 681** 682** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 683** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 684** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 685** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 686** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 687** to NULL. 688** 689** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 690** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 691** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 692** flag may be ORed in to indicate that only the data of the file 693** and not its inode needs to be synced. 694** 695** The integer values to xLock() and xUnlock() are one of 696** <ul> 697** <li> [SQLITE_LOCK_NONE], 698** <li> [SQLITE_LOCK_SHARED], 699** <li> [SQLITE_LOCK_RESERVED], 700** <li> [SQLITE_LOCK_PENDING], or 701** <li> [SQLITE_LOCK_EXCLUSIVE]. 702** </ul> 703** xLock() increases the lock. xUnlock() decreases the lock. 704** The xCheckReservedLock() method checks whether any database connection, 705** either in this process or in some other process, is holding a RESERVED, 706** PENDING, or EXCLUSIVE lock on the file. It returns true 707** if such a lock exists and false otherwise. 708** 709** The xFileControl() method is a generic interface that allows custom 710** VFS implementations to directly control an open file using the 711** [sqlite3_file_control()] interface. The second "op" argument is an 712** integer opcode. The third argument is a generic pointer intended to 713** point to a structure that may contain arguments or space in which to 714** write return values. Potential uses for xFileControl() might be 715** functions to enable blocking locks with timeouts, to change the 716** locking strategy (for example to use dot-file locks), to inquire 717** about the status of a lock, or to break stale locks. The SQLite 718** core reserves all opcodes less than 100 for its own use. 719** A [file control opcodes | list of opcodes] less than 100 is available. 720** Applications that define a custom xFileControl method should use opcodes 721** greater than 100 to avoid conflicts. VFS implementations should 722** return [SQLITE_NOTFOUND] for file control opcodes that they do not 723** recognize. 724** 725** The xSectorSize() method returns the sector size of the 726** device that underlies the file. The sector size is the 727** minimum write that can be performed without disturbing 728** other bytes in the file. The xDeviceCharacteristics() 729** method returns a bit vector describing behaviors of the 730** underlying device: 731** 732** <ul> 733** <li> [SQLITE_IOCAP_ATOMIC] 734** <li> [SQLITE_IOCAP_ATOMIC512] 735** <li> [SQLITE_IOCAP_ATOMIC1K] 736** <li> [SQLITE_IOCAP_ATOMIC2K] 737** <li> [SQLITE_IOCAP_ATOMIC4K] 738** <li> [SQLITE_IOCAP_ATOMIC8K] 739** <li> [SQLITE_IOCAP_ATOMIC16K] 740** <li> [SQLITE_IOCAP_ATOMIC32K] 741** <li> [SQLITE_IOCAP_ATOMIC64K] 742** <li> [SQLITE_IOCAP_SAFE_APPEND] 743** <li> [SQLITE_IOCAP_SEQUENTIAL] 744** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 745** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 746** <li> [SQLITE_IOCAP_IMMUTABLE] 747** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 748** </ul> 749** 750** The SQLITE_IOCAP_ATOMIC property means that all writes of 751** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 752** mean that writes of blocks that are nnn bytes in size and 753** are aligned to an address which is an integer multiple of 754** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 755** that when data is appended to a file, the data is appended 756** first then the size of the file is extended, never the other 757** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 758** information is written to disk in the same order as calls 759** to xWrite(). 760** 761** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 762** in the unread portions of the buffer with zeros. A VFS that 763** fails to zero-fill short reads might seem to work. However, 764** failure to zero-fill short reads will eventually lead to 765** database corruption. 766*/ 767typedef struct sqlite3_io_methods sqlite3_io_methods; 768struct sqlite3_io_methods { 769 int iVersion; 770 int (*xClose)(sqlite3_file*); 771 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 772 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 773 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 774 int (*xSync)(sqlite3_file*, int flags); 775 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 776 int (*xLock)(sqlite3_file*, int); 777 int (*xUnlock)(sqlite3_file*, int); 778 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 779 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 780 int (*xSectorSize)(sqlite3_file*); 781 int (*xDeviceCharacteristics)(sqlite3_file*); 782 /* Methods above are valid for version 1 */ 783 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 784 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 785 void (*xShmBarrier)(sqlite3_file*); 786 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 787 /* Methods above are valid for version 2 */ 788 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 789 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 790 /* Methods above are valid for version 3 */ 791 /* Additional methods may be added in future releases */ 792}; 793 794/* 795** CAPI3REF: Standard File Control Opcodes 796** KEYWORDS: {file control opcodes} {file control opcode} 797** 798** These integer constants are opcodes for the xFileControl method 799** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 800** interface. 801** 802** <ul> 803** <li>[[SQLITE_FCNTL_LOCKSTATE]] 804** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 805** opcode causes the xFileControl method to write the current state of 806** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 807** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 808** into an integer that the pArg argument points to. This capability 809** is used during testing and is only available when the SQLITE_TEST 810** compile-time option is used. 811** 812** <li>[[SQLITE_FCNTL_SIZE_HINT]] 813** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 814** layer a hint of how large the database file will grow to be during the 815** current transaction. This hint is not guaranteed to be accurate but it 816** is often close. The underlying VFS might choose to preallocate database 817** file space based on this hint in order to help writes to the database 818** file run faster. 819** 820** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 821** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 822** extends and truncates the database file in chunks of a size specified 823** by the user. The fourth argument to [sqlite3_file_control()] should 824** point to an integer (type int) containing the new chunk-size to use 825** for the nominated database. Allocating database file space in large 826** chunks (say 1MB at a time), may reduce file-system fragmentation and 827** improve performance on some systems. 828** 829** <li>[[SQLITE_FCNTL_FILE_POINTER]] 830** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 831** to the [sqlite3_file] object associated with a particular database 832** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 833** 834** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 835** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 836** to the [sqlite3_file] object associated with the journal file (either 837** the [rollback journal] or the [write-ahead log]) for a particular database 838** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 839** 840** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 841** No longer in use. 842** 843** <li>[[SQLITE_FCNTL_SYNC]] 844** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 845** sent to the VFS immediately before the xSync method is invoked on a 846** database file descriptor. Or, if the xSync method is not invoked 847** because the user has configured SQLite with 848** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 849** of the xSync method. In most cases, the pointer argument passed with 850** this file-control is NULL. However, if the database file is being synced 851** as part of a multi-database commit, the argument points to a nul-terminated 852** string containing the transactions master-journal file name. VFSes that 853** do not need this signal should silently ignore this opcode. Applications 854** should not call [sqlite3_file_control()] with this opcode as doing so may 855** disrupt the operation of the specialized VFSes that do require it. 856** 857** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 858** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 859** and sent to the VFS after a transaction has been committed immediately 860** but before the database is unlocked. VFSes that do not need this signal 861** should silently ignore this opcode. Applications should not call 862** [sqlite3_file_control()] with this opcode as doing so may disrupt the 863** operation of the specialized VFSes that do require it. 864** 865** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 866** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 867** retry counts and intervals for certain disk I/O operations for the 868** windows [VFS] in order to provide robustness in the presence of 869** anti-virus programs. By default, the windows VFS will retry file read, 870** file write, and file delete operations up to 10 times, with a delay 871** of 25 milliseconds before the first retry and with the delay increasing 872** by an additional 25 milliseconds with each subsequent retry. This 873** opcode allows these two values (10 retries and 25 milliseconds of delay) 874** to be adjusted. The values are changed for all database connections 875** within the same process. The argument is a pointer to an array of two 876** integers where the first integer is the new retry count and the second 877** integer is the delay. If either integer is negative, then the setting 878** is not changed but instead the prior value of that setting is written 879** into the array entry, allowing the current retry settings to be 880** interrogated. The zDbName parameter is ignored. 881** 882** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 883** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 884** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 885** write ahead log and shared memory files used for transaction control 886** are automatically deleted when the latest connection to the database 887** closes. Setting persistent WAL mode causes those files to persist after 888** close. Persisting the files is useful when other processes that do not 889** have write permission on the directory containing the database file want 890** to read the database file, as the WAL and shared memory files must exist 891** in order for the database to be readable. The fourth parameter to 892** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 893** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 894** WAL mode. If the integer is -1, then it is overwritten with the current 895** WAL persistence setting. 896** 897** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 898** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 899** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 900** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 901** xDeviceCharacteristics methods. The fourth parameter to 902** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 903** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 904** mode. If the integer is -1, then it is overwritten with the current 905** zero-damage mode setting. 906** 907** <li>[[SQLITE_FCNTL_OVERWRITE]] 908** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 909** a write transaction to indicate that, unless it is rolled back for some 910** reason, the entire database file will be overwritten by the current 911** transaction. This is used by VACUUM operations. 912** 913** <li>[[SQLITE_FCNTL_VFSNAME]] 914** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 915** all [VFSes] in the VFS stack. The names are of all VFS shims and the 916** final bottom-level VFS are written into memory obtained from 917** [sqlite3_malloc()] and the result is stored in the char* variable 918** that the fourth parameter of [sqlite3_file_control()] points to. 919** The caller is responsible for freeing the memory when done. As with 920** all file-control actions, there is no guarantee that this will actually 921** do anything. Callers should initialize the char* variable to a NULL 922** pointer in case this file-control is not implemented. This file-control 923** is intended for diagnostic use only. 924** 925** <li>[[SQLITE_FCNTL_VFS_POINTER]] 926** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 927** [VFSes] currently in use. ^(The argument X in 928** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 929** of type "[sqlite3_vfs] **". This opcodes will set *X 930** to a pointer to the top-level VFS.)^ 931** ^When there are multiple VFS shims in the stack, this opcode finds the 932** upper-most shim only. 933** 934** <li>[[SQLITE_FCNTL_PRAGMA]] 935** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 936** file control is sent to the open [sqlite3_file] object corresponding 937** to the database file to which the pragma statement refers. ^The argument 938** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 939** pointers to strings (char**) in which the second element of the array 940** is the name of the pragma and the third element is the argument to the 941** pragma or NULL if the pragma has no argument. ^The handler for an 942** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 943** of the char** argument point to a string obtained from [sqlite3_mprintf()] 944** or the equivalent and that string will become the result of the pragma or 945** the error message if the pragma fails. ^If the 946** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 947** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 948** file control returns [SQLITE_OK], then the parser assumes that the 949** VFS has handled the PRAGMA itself and the parser generates a no-op 950** prepared statement if result string is NULL, or that returns a copy 951** of the result string if the string is non-NULL. 952** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 953** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 954** that the VFS encountered an error while handling the [PRAGMA] and the 955** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 956** file control occurs at the beginning of pragma statement analysis and so 957** it is able to override built-in [PRAGMA] statements. 958** 959** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 960** ^The [SQLITE_FCNTL_BUSYHANDLER] 961** file-control may be invoked by SQLite on the database file handle 962** shortly after it is opened in order to provide a custom VFS with access 963** to the connections busy-handler callback. The argument is of type (void **) 964** - an array of two (void *) values. The first (void *) actually points 965** to a function of type (int (*)(void *)). In order to invoke the connections 966** busy-handler, this function should be invoked with the second (void *) in 967** the array as the only argument. If it returns non-zero, then the operation 968** should be retried. If it returns zero, the custom VFS should abandon the 969** current operation. 970** 971** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 972** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 973** to have SQLite generate a 974** temporary filename using the same algorithm that is followed to generate 975** temporary filenames for TEMP tables and other internal uses. The 976** argument should be a char** which will be filled with the filename 977** written into memory obtained from [sqlite3_malloc()]. The caller should 978** invoke [sqlite3_free()] on the result to avoid a memory leak. 979** 980** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 981** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 982** maximum number of bytes that will be used for memory-mapped I/O. 983** The argument is a pointer to a value of type sqlite3_int64 that 984** is an advisory maximum number of bytes in the file to memory map. The 985** pointer is overwritten with the old value. The limit is not changed if 986** the value originally pointed to is negative, and so the current limit 987** can be queried by passing in a pointer to a negative number. This 988** file-control is used internally to implement [PRAGMA mmap_size]. 989** 990** <li>[[SQLITE_FCNTL_TRACE]] 991** The [SQLITE_FCNTL_TRACE] file control provides advisory information 992** to the VFS about what the higher layers of the SQLite stack are doing. 993** This file control is used by some VFS activity tracing [shims]. 994** The argument is a zero-terminated string. Higher layers in the 995** SQLite stack may generate instances of this file control if 996** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 997** 998** <li>[[SQLITE_FCNTL_HAS_MOVED]] 999** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1000** pointer to an integer and it writes a boolean into that integer depending 1001** on whether or not the file has been renamed, moved, or deleted since it 1002** was first opened. 1003** 1004** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1005** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1006** underlying native file handle associated with a file handle. This file 1007** control interprets its argument as a pointer to a native file handle and 1008** writes the resulting value there. 1009** 1010** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1011** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1012** opcode causes the xFileControl method to swap the file handle with the one 1013** pointed to by the pArg argument. This capability is used during testing 1014** and only needs to be supported when SQLITE_TEST is defined. 1015** 1016** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1017** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1018** be advantageous to block on the next WAL lock if the lock is not immediately 1019** available. The WAL subsystem issues this signal during rare 1020** circumstances in order to fix a problem with priority inversion. 1021** Applications should <em>not</em> use this file-control. 1022** 1023** <li>[[SQLITE_FCNTL_ZIPVFS]] 1024** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1025** VFS should return SQLITE_NOTFOUND for this opcode. 1026** 1027** <li>[[SQLITE_FCNTL_RBU]] 1028** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1029** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1030** this opcode. 1031** 1032** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1033** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1034** the file descriptor is placed in "batch write mode", which 1035** means all subsequent write operations will be deferred and done 1036** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1037** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1038** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1039** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1040** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1041** no VFS interface calls on the same [sqlite3_file] file descriptor 1042** except for calls to the xWrite method and the xFileControl method 1043** with [SQLITE_FCNTL_SIZE_HINT]. 1044** 1045** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1046** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1047** operations since the previous successful call to 1048** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1049** This file control returns [SQLITE_OK] if and only if the writes were 1050** all performed successfully and have been committed to persistent storage. 1051** ^Regardless of whether or not it is successful, this file control takes 1052** the file descriptor out of batch write mode so that all subsequent 1053** write operations are independent. 1054** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1055** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1056** 1057** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1058** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1059** operations since the previous successful call to 1060** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1061** ^This file control takes the file descriptor out of batch write mode 1062** so that all subsequent write operations are independent. 1063** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1064** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1065** </ul> 1066*/ 1067#define SQLITE_FCNTL_LOCKSTATE 1 1068#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1069#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1070#define SQLITE_FCNTL_LAST_ERRNO 4 1071#define SQLITE_FCNTL_SIZE_HINT 5 1072#define SQLITE_FCNTL_CHUNK_SIZE 6 1073#define SQLITE_FCNTL_FILE_POINTER 7 1074#define SQLITE_FCNTL_SYNC_OMITTED 8 1075#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1076#define SQLITE_FCNTL_PERSIST_WAL 10 1077#define SQLITE_FCNTL_OVERWRITE 11 1078#define SQLITE_FCNTL_VFSNAME 12 1079#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1080#define SQLITE_FCNTL_PRAGMA 14 1081#define SQLITE_FCNTL_BUSYHANDLER 15 1082#define SQLITE_FCNTL_TEMPFILENAME 16 1083#define SQLITE_FCNTL_MMAP_SIZE 18 1084#define SQLITE_FCNTL_TRACE 19 1085#define SQLITE_FCNTL_HAS_MOVED 20 1086#define SQLITE_FCNTL_SYNC 21 1087#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1088#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1089#define SQLITE_FCNTL_WAL_BLOCK 24 1090#define SQLITE_FCNTL_ZIPVFS 25 1091#define SQLITE_FCNTL_RBU 26 1092#define SQLITE_FCNTL_VFS_POINTER 27 1093#define SQLITE_FCNTL_JOURNAL_POINTER 28 1094#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1095#define SQLITE_FCNTL_PDB 30 1096#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1097#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1098#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1099 1100/* deprecated names */ 1101#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1102#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1103#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1104 1105 1106/* 1107** CAPI3REF: Mutex Handle 1108** 1109** The mutex module within SQLite defines [sqlite3_mutex] to be an 1110** abstract type for a mutex object. The SQLite core never looks 1111** at the internal representation of an [sqlite3_mutex]. It only 1112** deals with pointers to the [sqlite3_mutex] object. 1113** 1114** Mutexes are created using [sqlite3_mutex_alloc()]. 1115*/ 1116typedef struct sqlite3_mutex sqlite3_mutex; 1117 1118/* 1119** CAPI3REF: Loadable Extension Thunk 1120** 1121** A pointer to the opaque sqlite3_api_routines structure is passed as 1122** the third parameter to entry points of [loadable extensions]. This 1123** structure must be typedefed in order to work around compiler warnings 1124** on some platforms. 1125*/ 1126typedef struct sqlite3_api_routines sqlite3_api_routines; 1127 1128/* 1129** CAPI3REF: OS Interface Object 1130** 1131** An instance of the sqlite3_vfs object defines the interface between 1132** the SQLite core and the underlying operating system. The "vfs" 1133** in the name of the object stands for "virtual file system". See 1134** the [VFS | VFS documentation] for further information. 1135** 1136** The VFS interface is sometimes extended by adding new methods onto 1137** the end. Each time such an extension occurs, the iVersion field 1138** is incremented. The iVersion value started out as 1 in 1139** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1140** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1141** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1142** may be appended to the sqlite3_vfs object and the iVersion value 1143** may increase again in future versions of SQLite. 1144** Note that the structure 1145** of the sqlite3_vfs object changes in the transition from 1146** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1147** and yet the iVersion field was not modified. 1148** 1149** The szOsFile field is the size of the subclassed [sqlite3_file] 1150** structure used by this VFS. mxPathname is the maximum length of 1151** a pathname in this VFS. 1152** 1153** Registered sqlite3_vfs objects are kept on a linked list formed by 1154** the pNext pointer. The [sqlite3_vfs_register()] 1155** and [sqlite3_vfs_unregister()] interfaces manage this list 1156** in a thread-safe way. The [sqlite3_vfs_find()] interface 1157** searches the list. Neither the application code nor the VFS 1158** implementation should use the pNext pointer. 1159** 1160** The pNext field is the only field in the sqlite3_vfs 1161** structure that SQLite will ever modify. SQLite will only access 1162** or modify this field while holding a particular static mutex. 1163** The application should never modify anything within the sqlite3_vfs 1164** object once the object has been registered. 1165** 1166** The zName field holds the name of the VFS module. The name must 1167** be unique across all VFS modules. 1168** 1169** [[sqlite3_vfs.xOpen]] 1170** ^SQLite guarantees that the zFilename parameter to xOpen 1171** is either a NULL pointer or string obtained 1172** from xFullPathname() with an optional suffix added. 1173** ^If a suffix is added to the zFilename parameter, it will 1174** consist of a single "-" character followed by no more than 1175** 11 alphanumeric and/or "-" characters. 1176** ^SQLite further guarantees that 1177** the string will be valid and unchanged until xClose() is 1178** called. Because of the previous sentence, 1179** the [sqlite3_file] can safely store a pointer to the 1180** filename if it needs to remember the filename for some reason. 1181** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1182** must invent its own temporary name for the file. ^Whenever the 1183** xFilename parameter is NULL it will also be the case that the 1184** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1185** 1186** The flags argument to xOpen() includes all bits set in 1187** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1188** or [sqlite3_open16()] is used, then flags includes at least 1189** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1190** If xOpen() opens a file read-only then it sets *pOutFlags to 1191** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1192** 1193** ^(SQLite will also add one of the following flags to the xOpen() 1194** call, depending on the object being opened: 1195** 1196** <ul> 1197** <li> [SQLITE_OPEN_MAIN_DB] 1198** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1199** <li> [SQLITE_OPEN_TEMP_DB] 1200** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1201** <li> [SQLITE_OPEN_TRANSIENT_DB] 1202** <li> [SQLITE_OPEN_SUBJOURNAL] 1203** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1204** <li> [SQLITE_OPEN_WAL] 1205** </ul>)^ 1206** 1207** The file I/O implementation can use the object type flags to 1208** change the way it deals with files. For example, an application 1209** that does not care about crash recovery or rollback might make 1210** the open of a journal file a no-op. Writes to this journal would 1211** also be no-ops, and any attempt to read the journal would return 1212** SQLITE_IOERR. Or the implementation might recognize that a database 1213** file will be doing page-aligned sector reads and writes in a random 1214** order and set up its I/O subsystem accordingly. 1215** 1216** SQLite might also add one of the following flags to the xOpen method: 1217** 1218** <ul> 1219** <li> [SQLITE_OPEN_DELETEONCLOSE] 1220** <li> [SQLITE_OPEN_EXCLUSIVE] 1221** </ul> 1222** 1223** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1224** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1225** will be set for TEMP databases and their journals, transient 1226** databases, and subjournals. 1227** 1228** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1229** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1230** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1231** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1232** SQLITE_OPEN_CREATE, is used to indicate that file should always 1233** be created, and that it is an error if it already exists. 1234** It is <i>not</i> used to indicate the file should be opened 1235** for exclusive access. 1236** 1237** ^At least szOsFile bytes of memory are allocated by SQLite 1238** to hold the [sqlite3_file] structure passed as the third 1239** argument to xOpen. The xOpen method does not have to 1240** allocate the structure; it should just fill it in. Note that 1241** the xOpen method must set the sqlite3_file.pMethods to either 1242** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1243** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1244** element will be valid after xOpen returns regardless of the success 1245** or failure of the xOpen call. 1246** 1247** [[sqlite3_vfs.xAccess]] 1248** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1249** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1250** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1251** to test whether a file is at least readable. The file can be a 1252** directory. 1253** 1254** ^SQLite will always allocate at least mxPathname+1 bytes for the 1255** output buffer xFullPathname. The exact size of the output buffer 1256** is also passed as a parameter to both methods. If the output buffer 1257** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1258** handled as a fatal error by SQLite, vfs implementations should endeavor 1259** to prevent this by setting mxPathname to a sufficiently large value. 1260** 1261** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1262** interfaces are not strictly a part of the filesystem, but they are 1263** included in the VFS structure for completeness. 1264** The xRandomness() function attempts to return nBytes bytes 1265** of good-quality randomness into zOut. The return value is 1266** the actual number of bytes of randomness obtained. 1267** The xSleep() method causes the calling thread to sleep for at 1268** least the number of microseconds given. ^The xCurrentTime() 1269** method returns a Julian Day Number for the current date and time as 1270** a floating point value. 1271** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1272** Day Number multiplied by 86400000 (the number of milliseconds in 1273** a 24-hour day). 1274** ^SQLite will use the xCurrentTimeInt64() method to get the current 1275** date and time if that method is available (if iVersion is 2 or 1276** greater and the function pointer is not NULL) and will fall back 1277** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1278** 1279** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1280** are not used by the SQLite core. These optional interfaces are provided 1281** by some VFSes to facilitate testing of the VFS code. By overriding 1282** system calls with functions under its control, a test program can 1283** simulate faults and error conditions that would otherwise be difficult 1284** or impossible to induce. The set of system calls that can be overridden 1285** varies from one VFS to another, and from one version of the same VFS to the 1286** next. Applications that use these interfaces must be prepared for any 1287** or all of these interfaces to be NULL or for their behavior to change 1288** from one release to the next. Applications must not attempt to access 1289** any of these methods if the iVersion of the VFS is less than 3. 1290*/ 1291typedef struct sqlite3_vfs sqlite3_vfs; 1292typedef void (*sqlite3_syscall_ptr)(void); 1293struct sqlite3_vfs { 1294 int iVersion; /* Structure version number (currently 3) */ 1295 int szOsFile; /* Size of subclassed sqlite3_file */ 1296 int mxPathname; /* Maximum file pathname length */ 1297 sqlite3_vfs *pNext; /* Next registered VFS */ 1298 const char *zName; /* Name of this virtual file system */ 1299 void *pAppData; /* Pointer to application-specific data */ 1300 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1301 int flags, int *pOutFlags); 1302 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1303 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1304 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1305 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1306 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1307 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1308 void (*xDlClose)(sqlite3_vfs*, void*); 1309 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1310 int (*xSleep)(sqlite3_vfs*, int microseconds); 1311 int (*xCurrentTime)(sqlite3_vfs*, double*); 1312 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1313 /* 1314 ** The methods above are in version 1 of the sqlite_vfs object 1315 ** definition. Those that follow are added in version 2 or later 1316 */ 1317 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1318 /* 1319 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1320 ** Those below are for version 3 and greater. 1321 */ 1322 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1323 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1324 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1325 /* 1326 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1327 ** New fields may be appended in future versions. The iVersion 1328 ** value will increment whenever this happens. 1329 */ 1330}; 1331 1332/* 1333** CAPI3REF: Flags for the xAccess VFS method 1334** 1335** These integer constants can be used as the third parameter to 1336** the xAccess method of an [sqlite3_vfs] object. They determine 1337** what kind of permissions the xAccess method is looking for. 1338** With SQLITE_ACCESS_EXISTS, the xAccess method 1339** simply checks whether the file exists. 1340** With SQLITE_ACCESS_READWRITE, the xAccess method 1341** checks whether the named directory is both readable and writable 1342** (in other words, if files can be added, removed, and renamed within 1343** the directory). 1344** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1345** [temp_store_directory pragma], though this could change in a future 1346** release of SQLite. 1347** With SQLITE_ACCESS_READ, the xAccess method 1348** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1349** currently unused, though it might be used in a future release of 1350** SQLite. 1351*/ 1352#define SQLITE_ACCESS_EXISTS 0 1353#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1354#define SQLITE_ACCESS_READ 2 /* Unused */ 1355 1356/* 1357** CAPI3REF: Flags for the xShmLock VFS method 1358** 1359** These integer constants define the various locking operations 1360** allowed by the xShmLock method of [sqlite3_io_methods]. The 1361** following are the only legal combinations of flags to the 1362** xShmLock method: 1363** 1364** <ul> 1365** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1366** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1367** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1368** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1369** </ul> 1370** 1371** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1372** was given on the corresponding lock. 1373** 1374** The xShmLock method can transition between unlocked and SHARED or 1375** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1376** and EXCLUSIVE. 1377*/ 1378#define SQLITE_SHM_UNLOCK 1 1379#define SQLITE_SHM_LOCK 2 1380#define SQLITE_SHM_SHARED 4 1381#define SQLITE_SHM_EXCLUSIVE 8 1382 1383/* 1384** CAPI3REF: Maximum xShmLock index 1385** 1386** The xShmLock method on [sqlite3_io_methods] may use values 1387** between 0 and this upper bound as its "offset" argument. 1388** The SQLite core will never attempt to acquire or release a 1389** lock outside of this range 1390*/ 1391#define SQLITE_SHM_NLOCK 8 1392 1393 1394/* 1395** CAPI3REF: Initialize The SQLite Library 1396** 1397** ^The sqlite3_initialize() routine initializes the 1398** SQLite library. ^The sqlite3_shutdown() routine 1399** deallocates any resources that were allocated by sqlite3_initialize(). 1400** These routines are designed to aid in process initialization and 1401** shutdown on embedded systems. Workstation applications using 1402** SQLite normally do not need to invoke either of these routines. 1403** 1404** A call to sqlite3_initialize() is an "effective" call if it is 1405** the first time sqlite3_initialize() is invoked during the lifetime of 1406** the process, or if it is the first time sqlite3_initialize() is invoked 1407** following a call to sqlite3_shutdown(). ^(Only an effective call 1408** of sqlite3_initialize() does any initialization. All other calls 1409** are harmless no-ops.)^ 1410** 1411** A call to sqlite3_shutdown() is an "effective" call if it is the first 1412** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1413** an effective call to sqlite3_shutdown() does any deinitialization. 1414** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1415** 1416** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1417** is not. The sqlite3_shutdown() interface must only be called from a 1418** single thread. All open [database connections] must be closed and all 1419** other SQLite resources must be deallocated prior to invoking 1420** sqlite3_shutdown(). 1421** 1422** Among other things, ^sqlite3_initialize() will invoke 1423** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1424** will invoke sqlite3_os_end(). 1425** 1426** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1427** ^If for some reason, sqlite3_initialize() is unable to initialize 1428** the library (perhaps it is unable to allocate a needed resource such 1429** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1430** 1431** ^The sqlite3_initialize() routine is called internally by many other 1432** SQLite interfaces so that an application usually does not need to 1433** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1434** calls sqlite3_initialize() so the SQLite library will be automatically 1435** initialized when [sqlite3_open()] is called if it has not be initialized 1436** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1437** compile-time option, then the automatic calls to sqlite3_initialize() 1438** are omitted and the application must call sqlite3_initialize() directly 1439** prior to using any other SQLite interface. For maximum portability, 1440** it is recommended that applications always invoke sqlite3_initialize() 1441** directly prior to using any other SQLite interface. Future releases 1442** of SQLite may require this. In other words, the behavior exhibited 1443** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1444** default behavior in some future release of SQLite. 1445** 1446** The sqlite3_os_init() routine does operating-system specific 1447** initialization of the SQLite library. The sqlite3_os_end() 1448** routine undoes the effect of sqlite3_os_init(). Typical tasks 1449** performed by these routines include allocation or deallocation 1450** of static resources, initialization of global variables, 1451** setting up a default [sqlite3_vfs] module, or setting up 1452** a default configuration using [sqlite3_config()]. 1453** 1454** The application should never invoke either sqlite3_os_init() 1455** or sqlite3_os_end() directly. The application should only invoke 1456** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1457** interface is called automatically by sqlite3_initialize() and 1458** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1459** implementations for sqlite3_os_init() and sqlite3_os_end() 1460** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1461** When [custom builds | built for other platforms] 1462** (using the [SQLITE_OS_OTHER=1] compile-time 1463** option) the application must supply a suitable implementation for 1464** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1465** implementation of sqlite3_os_init() or sqlite3_os_end() 1466** must return [SQLITE_OK] on success and some other [error code] upon 1467** failure. 1468*/ 1469int sqlite3_initialize(void); 1470int sqlite3_shutdown(void); 1471int sqlite3_os_init(void); 1472int sqlite3_os_end(void); 1473 1474/* 1475** CAPI3REF: Configuring The SQLite Library 1476** 1477** The sqlite3_config() interface is used to make global configuration 1478** changes to SQLite in order to tune SQLite to the specific needs of 1479** the application. The default configuration is recommended for most 1480** applications and so this routine is usually not necessary. It is 1481** provided to support rare applications with unusual needs. 1482** 1483** <b>The sqlite3_config() interface is not threadsafe. The application 1484** must ensure that no other SQLite interfaces are invoked by other 1485** threads while sqlite3_config() is running.</b> 1486** 1487** The sqlite3_config() interface 1488** may only be invoked prior to library initialization using 1489** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1490** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1491** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1492** Note, however, that ^sqlite3_config() can be called as part of the 1493** implementation of an application-defined [sqlite3_os_init()]. 1494** 1495** The first argument to sqlite3_config() is an integer 1496** [configuration option] that determines 1497** what property of SQLite is to be configured. Subsequent arguments 1498** vary depending on the [configuration option] 1499** in the first argument. 1500** 1501** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1502** ^If the option is unknown or SQLite is unable to set the option 1503** then this routine returns a non-zero [error code]. 1504*/ 1505int sqlite3_config(int, ...); 1506 1507/* 1508** CAPI3REF: Configure database connections 1509** METHOD: sqlite3 1510** 1511** The sqlite3_db_config() interface is used to make configuration 1512** changes to a [database connection]. The interface is similar to 1513** [sqlite3_config()] except that the changes apply to a single 1514** [database connection] (specified in the first argument). 1515** 1516** The second argument to sqlite3_db_config(D,V,...) is the 1517** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1518** that indicates what aspect of the [database connection] is being configured. 1519** Subsequent arguments vary depending on the configuration verb. 1520** 1521** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1522** the call is considered successful. 1523*/ 1524int sqlite3_db_config(sqlite3*, int op, ...); 1525 1526/* 1527** CAPI3REF: Memory Allocation Routines 1528** 1529** An instance of this object defines the interface between SQLite 1530** and low-level memory allocation routines. 1531** 1532** This object is used in only one place in the SQLite interface. 1533** A pointer to an instance of this object is the argument to 1534** [sqlite3_config()] when the configuration option is 1535** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1536** By creating an instance of this object 1537** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1538** during configuration, an application can specify an alternative 1539** memory allocation subsystem for SQLite to use for all of its 1540** dynamic memory needs. 1541** 1542** Note that SQLite comes with several [built-in memory allocators] 1543** that are perfectly adequate for the overwhelming majority of applications 1544** and that this object is only useful to a tiny minority of applications 1545** with specialized memory allocation requirements. This object is 1546** also used during testing of SQLite in order to specify an alternative 1547** memory allocator that simulates memory out-of-memory conditions in 1548** order to verify that SQLite recovers gracefully from such 1549** conditions. 1550** 1551** The xMalloc, xRealloc, and xFree methods must work like the 1552** malloc(), realloc() and free() functions from the standard C library. 1553** ^SQLite guarantees that the second argument to 1554** xRealloc is always a value returned by a prior call to xRoundup. 1555** 1556** xSize should return the allocated size of a memory allocation 1557** previously obtained from xMalloc or xRealloc. The allocated size 1558** is always at least as big as the requested size but may be larger. 1559** 1560** The xRoundup method returns what would be the allocated size of 1561** a memory allocation given a particular requested size. Most memory 1562** allocators round up memory allocations at least to the next multiple 1563** of 8. Some allocators round up to a larger multiple or to a power of 2. 1564** Every memory allocation request coming in through [sqlite3_malloc()] 1565** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1566** that causes the corresponding memory allocation to fail. 1567** 1568** The xInit method initializes the memory allocator. For example, 1569** it might allocate any require mutexes or initialize internal data 1570** structures. The xShutdown method is invoked (indirectly) by 1571** [sqlite3_shutdown()] and should deallocate any resources acquired 1572** by xInit. The pAppData pointer is used as the only parameter to 1573** xInit and xShutdown. 1574** 1575** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1576** the xInit method, so the xInit method need not be threadsafe. The 1577** xShutdown method is only called from [sqlite3_shutdown()] so it does 1578** not need to be threadsafe either. For all other methods, SQLite 1579** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1580** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1581** it is by default) and so the methods are automatically serialized. 1582** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1583** methods must be threadsafe or else make their own arrangements for 1584** serialization. 1585** 1586** SQLite will never invoke xInit() more than once without an intervening 1587** call to xShutdown(). 1588*/ 1589typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1590struct sqlite3_mem_methods { 1591 void *(*xMalloc)(int); /* Memory allocation function */ 1592 void (*xFree)(void*); /* Free a prior allocation */ 1593 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1594 int (*xSize)(void*); /* Return the size of an allocation */ 1595 int (*xRoundup)(int); /* Round up request size to allocation size */ 1596 int (*xInit)(void*); /* Initialize the memory allocator */ 1597 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1598 void *pAppData; /* Argument to xInit() and xShutdown() */ 1599}; 1600 1601/* 1602** CAPI3REF: Configuration Options 1603** KEYWORDS: {configuration option} 1604** 1605** These constants are the available integer configuration options that 1606** can be passed as the first argument to the [sqlite3_config()] interface. 1607** 1608** New configuration options may be added in future releases of SQLite. 1609** Existing configuration options might be discontinued. Applications 1610** should check the return code from [sqlite3_config()] to make sure that 1611** the call worked. The [sqlite3_config()] interface will return a 1612** non-zero [error code] if a discontinued or unsupported configuration option 1613** is invoked. 1614** 1615** <dl> 1616** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1617** <dd>There are no arguments to this option. ^This option sets the 1618** [threading mode] to Single-thread. In other words, it disables 1619** all mutexing and puts SQLite into a mode where it can only be used 1620** by a single thread. ^If SQLite is compiled with 1621** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1622** it is not possible to change the [threading mode] from its default 1623** value of Single-thread and so [sqlite3_config()] will return 1624** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1625** configuration option.</dd> 1626** 1627** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1628** <dd>There are no arguments to this option. ^This option sets the 1629** [threading mode] to Multi-thread. In other words, it disables 1630** mutexing on [database connection] and [prepared statement] objects. 1631** The application is responsible for serializing access to 1632** [database connections] and [prepared statements]. But other mutexes 1633** are enabled so that SQLite will be safe to use in a multi-threaded 1634** environment as long as no two threads attempt to use the same 1635** [database connection] at the same time. ^If SQLite is compiled with 1636** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1637** it is not possible to set the Multi-thread [threading mode] and 1638** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1639** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1640** 1641** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1642** <dd>There are no arguments to this option. ^This option sets the 1643** [threading mode] to Serialized. In other words, this option enables 1644** all mutexes including the recursive 1645** mutexes on [database connection] and [prepared statement] objects. 1646** In this mode (which is the default when SQLite is compiled with 1647** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1648** to [database connections] and [prepared statements] so that the 1649** application is free to use the same [database connection] or the 1650** same [prepared statement] in different threads at the same time. 1651** ^If SQLite is compiled with 1652** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1653** it is not possible to set the Serialized [threading mode] and 1654** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1655** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1656** 1657** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1658** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1659** a pointer to an instance of the [sqlite3_mem_methods] structure. 1660** The argument specifies 1661** alternative low-level memory allocation routines to be used in place of 1662** the memory allocation routines built into SQLite.)^ ^SQLite makes 1663** its own private copy of the content of the [sqlite3_mem_methods] structure 1664** before the [sqlite3_config()] call returns.</dd> 1665** 1666** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1667** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1668** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1669** The [sqlite3_mem_methods] 1670** structure is filled with the currently defined memory allocation routines.)^ 1671** This option can be used to overload the default memory allocation 1672** routines with a wrapper that simulations memory allocation failure or 1673** tracks memory usage, for example. </dd> 1674** 1675** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1676** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1677** type int, interpreted as a boolean, which if true provides a hint to 1678** SQLite that it should avoid large memory allocations if possible. 1679** SQLite will run faster if it is free to make large memory allocations, 1680** but some application might prefer to run slower in exchange for 1681** guarantees about memory fragmentation that are possible if large 1682** allocations are avoided. This hint is normally off. 1683** </dd> 1684** 1685** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1686** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1687** interpreted as a boolean, which enables or disables the collection of 1688** memory allocation statistics. ^(When memory allocation statistics are 1689** disabled, the following SQLite interfaces become non-operational: 1690** <ul> 1691** <li> [sqlite3_memory_used()] 1692** <li> [sqlite3_memory_highwater()] 1693** <li> [sqlite3_soft_heap_limit64()] 1694** <li> [sqlite3_status64()] 1695** </ul>)^ 1696** ^Memory allocation statistics are enabled by default unless SQLite is 1697** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1698** allocation statistics are disabled by default. 1699** </dd> 1700** 1701** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1702** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1703** </dd> 1704** 1705** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1706** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1707** that SQLite can use for the database page cache with the default page 1708** cache implementation. 1709** This configuration option is a no-op if an application-define page 1710** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1711** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1712** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1713** and the number of cache lines (N). 1714** The sz argument should be the size of the largest database page 1715** (a power of two between 512 and 65536) plus some extra bytes for each 1716** page header. ^The number of extra bytes needed by the page header 1717** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1718** ^It is harmless, apart from the wasted memory, 1719** for the sz parameter to be larger than necessary. The pMem 1720** argument must be either a NULL pointer or a pointer to an 8-byte 1721** aligned block of memory of at least sz*N bytes, otherwise 1722** subsequent behavior is undefined. 1723** ^When pMem is not NULL, SQLite will strive to use the memory provided 1724** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1725** a page cache line is larger than sz bytes or if all of the pMem buffer 1726** is exhausted. 1727** ^If pMem is NULL and N is non-zero, then each database connection 1728** does an initial bulk allocation for page cache memory 1729** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1730** of -1024*N bytes if N is negative, . ^If additional 1731** page cache memory is needed beyond what is provided by the initial 1732** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1733** additional cache line. </dd> 1734** 1735** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1736** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1737** that SQLite will use for all of its dynamic memory allocation needs 1738** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1739** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1740** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1741** [SQLITE_ERROR] if invoked otherwise. 1742** ^There are three arguments to SQLITE_CONFIG_HEAP: 1743** An 8-byte aligned pointer to the memory, 1744** the number of bytes in the memory buffer, and the minimum allocation size. 1745** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1746** to using its default memory allocator (the system malloc() implementation), 1747** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1748** memory pointer is not NULL then the alternative memory 1749** allocator is engaged to handle all of SQLites memory allocation needs. 1750** The first pointer (the memory pointer) must be aligned to an 8-byte 1751** boundary or subsequent behavior of SQLite will be undefined. 1752** The minimum allocation size is capped at 2**12. Reasonable values 1753** for the minimum allocation size are 2**5 through 2**8.</dd> 1754** 1755** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1756** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1757** pointer to an instance of the [sqlite3_mutex_methods] structure. 1758** The argument specifies alternative low-level mutex routines to be used 1759** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1760** the content of the [sqlite3_mutex_methods] structure before the call to 1761** [sqlite3_config()] returns. ^If SQLite is compiled with 1762** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1763** the entire mutexing subsystem is omitted from the build and hence calls to 1764** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1765** return [SQLITE_ERROR].</dd> 1766** 1767** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1768** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1769** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1770** [sqlite3_mutex_methods] 1771** structure is filled with the currently defined mutex routines.)^ 1772** This option can be used to overload the default mutex allocation 1773** routines with a wrapper used to track mutex usage for performance 1774** profiling or testing, for example. ^If SQLite is compiled with 1775** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1776** the entire mutexing subsystem is omitted from the build and hence calls to 1777** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1778** return [SQLITE_ERROR].</dd> 1779** 1780** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1781** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1782** the default size of lookaside memory on each [database connection]. 1783** The first argument is the 1784** size of each lookaside buffer slot and the second is the number of 1785** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1786** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1787** option to [sqlite3_db_config()] can be used to change the lookaside 1788** configuration on individual connections.)^ </dd> 1789** 1790** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1791** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1792** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1793** the interface to a custom page cache implementation.)^ 1794** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1795** 1796** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1797** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1798** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1799** the current page cache implementation into that object.)^ </dd> 1800** 1801** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1802** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1803** global [error log]. 1804** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1805** function with a call signature of void(*)(void*,int,const char*), 1806** and a pointer to void. ^If the function pointer is not NULL, it is 1807** invoked by [sqlite3_log()] to process each logging event. ^If the 1808** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1809** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1810** passed through as the first parameter to the application-defined logger 1811** function whenever that function is invoked. ^The second parameter to 1812** the logger function is a copy of the first parameter to the corresponding 1813** [sqlite3_log()] call and is intended to be a [result code] or an 1814** [extended result code]. ^The third parameter passed to the logger is 1815** log message after formatting via [sqlite3_snprintf()]. 1816** The SQLite logging interface is not reentrant; the logger function 1817** supplied by the application must not invoke any SQLite interface. 1818** In a multi-threaded application, the application-defined logger 1819** function must be threadsafe. </dd> 1820** 1821** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1822** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1823** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1824** then URI handling is globally disabled.)^ ^If URI handling is globally 1825** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1826** [sqlite3_open16()] or 1827** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1828** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1829** connection is opened. ^If it is globally disabled, filenames are 1830** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1831** database connection is opened. ^(By default, URI handling is globally 1832** disabled. The default value may be changed by compiling with the 1833** [SQLITE_USE_URI] symbol defined.)^ 1834** 1835** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1836** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1837** argument which is interpreted as a boolean in order to enable or disable 1838** the use of covering indices for full table scans in the query optimizer. 1839** ^The default setting is determined 1840** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1841** if that compile-time option is omitted. 1842** The ability to disable the use of covering indices for full table scans 1843** is because some incorrectly coded legacy applications might malfunction 1844** when the optimization is enabled. Providing the ability to 1845** disable the optimization allows the older, buggy application code to work 1846** without change even with newer versions of SQLite. 1847** 1848** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1849** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1850** <dd> These options are obsolete and should not be used by new code. 1851** They are retained for backwards compatibility but are now no-ops. 1852** </dd> 1853** 1854** [[SQLITE_CONFIG_SQLLOG]] 1855** <dt>SQLITE_CONFIG_SQLLOG 1856** <dd>This option is only available if sqlite is compiled with the 1857** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1858** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1859** The second should be of type (void*). The callback is invoked by the library 1860** in three separate circumstances, identified by the value passed as the 1861** fourth parameter. If the fourth parameter is 0, then the database connection 1862** passed as the second argument has just been opened. The third argument 1863** points to a buffer containing the name of the main database file. If the 1864** fourth parameter is 1, then the SQL statement that the third parameter 1865** points to has just been executed. Or, if the fourth parameter is 2, then 1866** the connection being passed as the second parameter is being closed. The 1867** third parameter is passed NULL In this case. An example of using this 1868** configuration option can be seen in the "test_sqllog.c" source file in 1869** the canonical SQLite source tree.</dd> 1870** 1871** [[SQLITE_CONFIG_MMAP_SIZE]] 1872** <dt>SQLITE_CONFIG_MMAP_SIZE 1873** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1874** that are the default mmap size limit (the default setting for 1875** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1876** ^The default setting can be overridden by each database connection using 1877** either the [PRAGMA mmap_size] command, or by using the 1878** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1879** will be silently truncated if necessary so that it does not exceed the 1880** compile-time maximum mmap size set by the 1881** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1882** ^If either argument to this option is negative, then that argument is 1883** changed to its compile-time default. 1884** 1885** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1886** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1887** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1888** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1889** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1890** that specifies the maximum size of the created heap. 1891** 1892** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1893** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1894** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1895** is a pointer to an integer and writes into that integer the number of extra 1896** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1897** The amount of extra space required can change depending on the compiler, 1898** target platform, and SQLite version. 1899** 1900** [[SQLITE_CONFIG_PMASZ]] 1901** <dt>SQLITE_CONFIG_PMASZ 1902** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1903** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1904** sorter to that integer. The default minimum PMA Size is set by the 1905** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1906** to help with sort operations when multithreaded sorting 1907** is enabled (using the [PRAGMA threads] command) and the amount of content 1908** to be sorted exceeds the page size times the minimum of the 1909** [PRAGMA cache_size] setting and this value. 1910** 1911** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1912** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1913** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1914** becomes the [statement journal] spill-to-disk threshold. 1915** [Statement journals] are held in memory until their size (in bytes) 1916** exceeds this threshold, at which point they are written to disk. 1917** Or if the threshold is -1, statement journals are always held 1918** exclusively in memory. 1919** Since many statement journals never become large, setting the spill 1920** threshold to a value such as 64KiB can greatly reduce the amount of 1921** I/O required to support statement rollback. 1922** The default value for this setting is controlled by the 1923** [SQLITE_STMTJRNL_SPILL] compile-time option. 1924** </dl> 1925*/ 1926#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1927#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1928#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1929#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1930#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1931#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1932#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1933#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1934#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1935#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1936#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1937/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1938#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1939#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1940#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1941#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1942#define SQLITE_CONFIG_URI 17 /* int */ 1943#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1944#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1945#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1946#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1947#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1948#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1949#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1950#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1951#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1952#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1953 1954/* 1955** CAPI3REF: Database Connection Configuration Options 1956** 1957** These constants are the available integer configuration options that 1958** can be passed as the second argument to the [sqlite3_db_config()] interface. 1959** 1960** New configuration options may be added in future releases of SQLite. 1961** Existing configuration options might be discontinued. Applications 1962** should check the return code from [sqlite3_db_config()] to make sure that 1963** the call worked. ^The [sqlite3_db_config()] interface will return a 1964** non-zero [error code] if a discontinued or unsupported configuration option 1965** is invoked. 1966** 1967** <dl> 1968** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1969** <dd> ^This option takes three additional arguments that determine the 1970** [lookaside memory allocator] configuration for the [database connection]. 1971** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1972** pointer to a memory buffer to use for lookaside memory. 1973** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1974** may be NULL in which case SQLite will allocate the 1975** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1976** size of each lookaside buffer slot. ^The third argument is the number of 1977** slots. The size of the buffer in the first argument must be greater than 1978** or equal to the product of the second and third arguments. The buffer 1979** must be aligned to an 8-byte boundary. ^If the second argument to 1980** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1981** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1982** configuration for a database connection can only be changed when that 1983** connection is not currently using lookaside memory, or in other words 1984** when the "current value" returned by 1985** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1986** Any attempt to change the lookaside memory configuration when lookaside 1987** memory is in use leaves the configuration unchanged and returns 1988** [SQLITE_BUSY].)^</dd> 1989** 1990** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1991** <dd> ^This option is used to enable or disable the enforcement of 1992** [foreign key constraints]. There should be two additional arguments. 1993** The first argument is an integer which is 0 to disable FK enforcement, 1994** positive to enable FK enforcement or negative to leave FK enforcement 1995** unchanged. The second parameter is a pointer to an integer into which 1996** is written 0 or 1 to indicate whether FK enforcement is off or on 1997** following this call. The second parameter may be a NULL pointer, in 1998** which case the FK enforcement setting is not reported back. </dd> 1999** 2000** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2001** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2002** There should be two additional arguments. 2003** The first argument is an integer which is 0 to disable triggers, 2004** positive to enable triggers or negative to leave the setting unchanged. 2005** The second parameter is a pointer to an integer into which 2006** is written 0 or 1 to indicate whether triggers are disabled or enabled 2007** following this call. The second parameter may be a NULL pointer, in 2008** which case the trigger setting is not reported back. </dd> 2009** 2010** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2011** <dd> ^This option is used to enable or disable the two-argument 2012** version of the [fts3_tokenizer()] function which is part of the 2013** [FTS3] full-text search engine extension. 2014** There should be two additional arguments. 2015** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2016** positive to enable fts3_tokenizer() or negative to leave the setting 2017** unchanged. 2018** The second parameter is a pointer to an integer into which 2019** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2020** following this call. The second parameter may be a NULL pointer, in 2021** which case the new setting is not reported back. </dd> 2022** 2023** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2024** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2025** interface independently of the [load_extension()] SQL function. 2026** The [sqlite3_enable_load_extension()] API enables or disables both the 2027** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2028** There should be two additional arguments. 2029** When the first argument to this interface is 1, then only the C-API is 2030** enabled and the SQL function remains disabled. If the first argument to 2031** this interface is 0, then both the C-API and the SQL function are disabled. 2032** If the first argument is -1, then no changes are made to state of either the 2033** C-API or the SQL function. 2034** The second parameter is a pointer to an integer into which 2035** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2036** is disabled or enabled following this call. The second parameter may 2037** be a NULL pointer, in which case the new setting is not reported back. 2038** </dd> 2039** 2040** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2041** <dd> ^This option is used to change the name of the "main" database 2042** schema. ^The sole argument is a pointer to a constant UTF8 string 2043** which will become the new schema name in place of "main". ^SQLite 2044** does not make a copy of the new main schema name string, so the application 2045** must ensure that the argument passed into this DBCONFIG option is unchanged 2046** until after the database connection closes. 2047** </dd> 2048** 2049** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2050** <dd> Usually, when a database in wal mode is closed or detached from a 2051** database handle, SQLite checks if this will mean that there are now no 2052** connections at all to the database. If so, it performs a checkpoint 2053** operation before closing the connection. This option may be used to 2054** override this behaviour. The first parameter passed to this operation 2055** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2056** default) to enable them. The second parameter is a pointer to an integer 2057** into which is written 0 or 1 to indicate whether checkpoints-on-close 2058** have been disabled - 0 if they are not disabled, 1 if they are. 2059** </dd> 2060** 2061** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2062** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2063** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2064** a single SQL query statement will always use the same algorithm regardless 2065** of values of [bound parameters].)^ The QPSG disables some query optimizations 2066** that look at the values of bound parameters, which can make some queries 2067** slower. But the QPSG has the advantage of more predictable behavior. With 2068** the QPSG active, SQLite will always use the same query plan in the field as 2069** was used during testing in the lab. 2070** </dd> 2071** 2072** </dl> 2073*/ 2074#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2075#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2076#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2077#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2078#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2079#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2080#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2081#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2082 2083 2084/* 2085** CAPI3REF: Enable Or Disable Extended Result Codes 2086** METHOD: sqlite3 2087** 2088** ^The sqlite3_extended_result_codes() routine enables or disables the 2089** [extended result codes] feature of SQLite. ^The extended result 2090** codes are disabled by default for historical compatibility. 2091*/ 2092int sqlite3_extended_result_codes(sqlite3*, int onoff); 2093 2094/* 2095** CAPI3REF: Last Insert Rowid 2096** METHOD: sqlite3 2097** 2098** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2099** has a unique 64-bit signed 2100** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2101** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2102** names are not also used by explicitly declared columns. ^If 2103** the table has a column of type [INTEGER PRIMARY KEY] then that column 2104** is another alias for the rowid. 2105** 2106** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2107** the most recent successful [INSERT] into a rowid table or [virtual table] 2108** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2109** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2110** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2111** zero. 2112** 2113** As well as being set automatically as rows are inserted into database 2114** tables, the value returned by this function may be set explicitly by 2115** [sqlite3_set_last_insert_rowid()] 2116** 2117** Some virtual table implementations may INSERT rows into rowid tables as 2118** part of committing a transaction (e.g. to flush data accumulated in memory 2119** to disk). In this case subsequent calls to this function return the rowid 2120** associated with these internal INSERT operations, which leads to 2121** unintuitive results. Virtual table implementations that do write to rowid 2122** tables in this way can avoid this problem by restoring the original 2123** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2124** control to the user. 2125** 2126** ^(If an [INSERT] occurs within a trigger then this routine will 2127** return the [rowid] of the inserted row as long as the trigger is 2128** running. Once the trigger program ends, the value returned 2129** by this routine reverts to what it was before the trigger was fired.)^ 2130** 2131** ^An [INSERT] that fails due to a constraint violation is not a 2132** successful [INSERT] and does not change the value returned by this 2133** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2134** and INSERT OR ABORT make no changes to the return value of this 2135** routine when their insertion fails. ^(When INSERT OR REPLACE 2136** encounters a constraint violation, it does not fail. The 2137** INSERT continues to completion after deleting rows that caused 2138** the constraint problem so INSERT OR REPLACE will always change 2139** the return value of this interface.)^ 2140** 2141** ^For the purposes of this routine, an [INSERT] is considered to 2142** be successful even if it is subsequently rolled back. 2143** 2144** This function is accessible to SQL statements via the 2145** [last_insert_rowid() SQL function]. 2146** 2147** If a separate thread performs a new [INSERT] on the same 2148** database connection while the [sqlite3_last_insert_rowid()] 2149** function is running and thus changes the last insert [rowid], 2150** then the value returned by [sqlite3_last_insert_rowid()] is 2151** unpredictable and might not equal either the old or the new 2152** last insert [rowid]. 2153*/ 2154sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2155 2156/* 2157** CAPI3REF: Set the Last Insert Rowid value. 2158** METHOD: sqlite3 2159** 2160** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2161** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2162** without inserting a row into the database. 2163*/ 2164void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2165 2166/* 2167** CAPI3REF: Count The Number Of Rows Modified 2168** METHOD: sqlite3 2169** 2170** ^This function returns the number of rows modified, inserted or 2171** deleted by the most recently completed INSERT, UPDATE or DELETE 2172** statement on the database connection specified by the only parameter. 2173** ^Executing any other type of SQL statement does not modify the value 2174** returned by this function. 2175** 2176** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2177** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2178** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2179** 2180** Changes to a view that are intercepted by 2181** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2182** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2183** DELETE statement run on a view is always zero. Only changes made to real 2184** tables are counted. 2185** 2186** Things are more complicated if the sqlite3_changes() function is 2187** executed while a trigger program is running. This may happen if the 2188** program uses the [changes() SQL function], or if some other callback 2189** function invokes sqlite3_changes() directly. Essentially: 2190** 2191** <ul> 2192** <li> ^(Before entering a trigger program the value returned by 2193** sqlite3_changes() function is saved. After the trigger program 2194** has finished, the original value is restored.)^ 2195** 2196** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2197** statement sets the value returned by sqlite3_changes() 2198** upon completion as normal. Of course, this value will not include 2199** any changes performed by sub-triggers, as the sqlite3_changes() 2200** value will be saved and restored after each sub-trigger has run.)^ 2201** </ul> 2202** 2203** ^This means that if the changes() SQL function (or similar) is used 2204** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2205** returns the value as set when the calling statement began executing. 2206** ^If it is used by the second or subsequent such statement within a trigger 2207** program, the value returned reflects the number of rows modified by the 2208** previous INSERT, UPDATE or DELETE statement within the same trigger. 2209** 2210** See also the [sqlite3_total_changes()] interface, the 2211** [count_changes pragma], and the [changes() SQL function]. 2212** 2213** If a separate thread makes changes on the same database connection 2214** while [sqlite3_changes()] is running then the value returned 2215** is unpredictable and not meaningful. 2216*/ 2217int sqlite3_changes(sqlite3*); 2218 2219/* 2220** CAPI3REF: Total Number Of Rows Modified 2221** METHOD: sqlite3 2222** 2223** ^This function returns the total number of rows inserted, modified or 2224** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2225** since the database connection was opened, including those executed as 2226** part of trigger programs. ^Executing any other type of SQL statement 2227** does not affect the value returned by sqlite3_total_changes(). 2228** 2229** ^Changes made as part of [foreign key actions] are included in the 2230** count, but those made as part of REPLACE constraint resolution are 2231** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2232** are not counted. 2233** 2234** See also the [sqlite3_changes()] interface, the 2235** [count_changes pragma], and the [total_changes() SQL function]. 2236** 2237** If a separate thread makes changes on the same database connection 2238** while [sqlite3_total_changes()] is running then the value 2239** returned is unpredictable and not meaningful. 2240*/ 2241int sqlite3_total_changes(sqlite3*); 2242 2243/* 2244** CAPI3REF: Interrupt A Long-Running Query 2245** METHOD: sqlite3 2246** 2247** ^This function causes any pending database operation to abort and 2248** return at its earliest opportunity. This routine is typically 2249** called in response to a user action such as pressing "Cancel" 2250** or Ctrl-C where the user wants a long query operation to halt 2251** immediately. 2252** 2253** ^It is safe to call this routine from a thread different from the 2254** thread that is currently running the database operation. But it 2255** is not safe to call this routine with a [database connection] that 2256** is closed or might close before sqlite3_interrupt() returns. 2257** 2258** ^If an SQL operation is very nearly finished at the time when 2259** sqlite3_interrupt() is called, then it might not have an opportunity 2260** to be interrupted and might continue to completion. 2261** 2262** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2263** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2264** that is inside an explicit transaction, then the entire transaction 2265** will be rolled back automatically. 2266** 2267** ^The sqlite3_interrupt(D) call is in effect until all currently running 2268** SQL statements on [database connection] D complete. ^Any new SQL statements 2269** that are started after the sqlite3_interrupt() call and before the 2270** running statements reaches zero are interrupted as if they had been 2271** running prior to the sqlite3_interrupt() call. ^New SQL statements 2272** that are started after the running statement count reaches zero are 2273** not effected by the sqlite3_interrupt(). 2274** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2275** SQL statements is a no-op and has no effect on SQL statements 2276** that are started after the sqlite3_interrupt() call returns. 2277*/ 2278void sqlite3_interrupt(sqlite3*); 2279 2280/* 2281** CAPI3REF: Determine If An SQL Statement Is Complete 2282** 2283** These routines are useful during command-line input to determine if the 2284** currently entered text seems to form a complete SQL statement or 2285** if additional input is needed before sending the text into 2286** SQLite for parsing. ^These routines return 1 if the input string 2287** appears to be a complete SQL statement. ^A statement is judged to be 2288** complete if it ends with a semicolon token and is not a prefix of a 2289** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2290** string literals or quoted identifier names or comments are not 2291** independent tokens (they are part of the token in which they are 2292** embedded) and thus do not count as a statement terminator. ^Whitespace 2293** and comments that follow the final semicolon are ignored. 2294** 2295** ^These routines return 0 if the statement is incomplete. ^If a 2296** memory allocation fails, then SQLITE_NOMEM is returned. 2297** 2298** ^These routines do not parse the SQL statements thus 2299** will not detect syntactically incorrect SQL. 2300** 2301** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2302** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2303** automatically by sqlite3_complete16(). If that initialization fails, 2304** then the return value from sqlite3_complete16() will be non-zero 2305** regardless of whether or not the input SQL is complete.)^ 2306** 2307** The input to [sqlite3_complete()] must be a zero-terminated 2308** UTF-8 string. 2309** 2310** The input to [sqlite3_complete16()] must be a zero-terminated 2311** UTF-16 string in native byte order. 2312*/ 2313int sqlite3_complete(const char *sql); 2314int sqlite3_complete16(const void *sql); 2315 2316/* 2317** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2318** KEYWORDS: {busy-handler callback} {busy handler} 2319** METHOD: sqlite3 2320** 2321** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2322** that might be invoked with argument P whenever 2323** an attempt is made to access a database table associated with 2324** [database connection] D when another thread 2325** or process has the table locked. 2326** The sqlite3_busy_handler() interface is used to implement 2327** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2328** 2329** ^If the busy callback is NULL, then [SQLITE_BUSY] 2330** is returned immediately upon encountering the lock. ^If the busy callback 2331** is not NULL, then the callback might be invoked with two arguments. 2332** 2333** ^The first argument to the busy handler is a copy of the void* pointer which 2334** is the third argument to sqlite3_busy_handler(). ^The second argument to 2335** the busy handler callback is the number of times that the busy handler has 2336** been invoked previously for the same locking event. ^If the 2337** busy callback returns 0, then no additional attempts are made to 2338** access the database and [SQLITE_BUSY] is returned 2339** to the application. 2340** ^If the callback returns non-zero, then another attempt 2341** is made to access the database and the cycle repeats. 2342** 2343** The presence of a busy handler does not guarantee that it will be invoked 2344** when there is lock contention. ^If SQLite determines that invoking the busy 2345** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2346** to the application instead of invoking the 2347** busy handler. 2348** Consider a scenario where one process is holding a read lock that 2349** it is trying to promote to a reserved lock and 2350** a second process is holding a reserved lock that it is trying 2351** to promote to an exclusive lock. The first process cannot proceed 2352** because it is blocked by the second and the second process cannot 2353** proceed because it is blocked by the first. If both processes 2354** invoke the busy handlers, neither will make any progress. Therefore, 2355** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2356** will induce the first process to release its read lock and allow 2357** the second process to proceed. 2358** 2359** ^The default busy callback is NULL. 2360** 2361** ^(There can only be a single busy handler defined for each 2362** [database connection]. Setting a new busy handler clears any 2363** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2364** or evaluating [PRAGMA busy_timeout=N] will change the 2365** busy handler and thus clear any previously set busy handler. 2366** 2367** The busy callback should not take any actions which modify the 2368** database connection that invoked the busy handler. In other words, 2369** the busy handler is not reentrant. Any such actions 2370** result in undefined behavior. 2371** 2372** A busy handler must not close the database connection 2373** or [prepared statement] that invoked the busy handler. 2374*/ 2375int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2376 2377/* 2378** CAPI3REF: Set A Busy Timeout 2379** METHOD: sqlite3 2380** 2381** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2382** for a specified amount of time when a table is locked. ^The handler 2383** will sleep multiple times until at least "ms" milliseconds of sleeping 2384** have accumulated. ^After at least "ms" milliseconds of sleeping, 2385** the handler returns 0 which causes [sqlite3_step()] to return 2386** [SQLITE_BUSY]. 2387** 2388** ^Calling this routine with an argument less than or equal to zero 2389** turns off all busy handlers. 2390** 2391** ^(There can only be a single busy handler for a particular 2392** [database connection] at any given moment. If another busy handler 2393** was defined (using [sqlite3_busy_handler()]) prior to calling 2394** this routine, that other busy handler is cleared.)^ 2395** 2396** See also: [PRAGMA busy_timeout] 2397*/ 2398int sqlite3_busy_timeout(sqlite3*, int ms); 2399 2400/* 2401** CAPI3REF: Convenience Routines For Running Queries 2402** METHOD: sqlite3 2403** 2404** This is a legacy interface that is preserved for backwards compatibility. 2405** Use of this interface is not recommended. 2406** 2407** Definition: A <b>result table</b> is memory data structure created by the 2408** [sqlite3_get_table()] interface. A result table records the 2409** complete query results from one or more queries. 2410** 2411** The table conceptually has a number of rows and columns. But 2412** these numbers are not part of the result table itself. These 2413** numbers are obtained separately. Let N be the number of rows 2414** and M be the number of columns. 2415** 2416** A result table is an array of pointers to zero-terminated UTF-8 strings. 2417** There are (N+1)*M elements in the array. The first M pointers point 2418** to zero-terminated strings that contain the names of the columns. 2419** The remaining entries all point to query results. NULL values result 2420** in NULL pointers. All other values are in their UTF-8 zero-terminated 2421** string representation as returned by [sqlite3_column_text()]. 2422** 2423** A result table might consist of one or more memory allocations. 2424** It is not safe to pass a result table directly to [sqlite3_free()]. 2425** A result table should be deallocated using [sqlite3_free_table()]. 2426** 2427** ^(As an example of the result table format, suppose a query result 2428** is as follows: 2429** 2430** <blockquote><pre> 2431** Name | Age 2432** ----------------------- 2433** Alice | 43 2434** Bob | 28 2435** Cindy | 21 2436** </pre></blockquote> 2437** 2438** There are two column (M==2) and three rows (N==3). Thus the 2439** result table has 8 entries. Suppose the result table is stored 2440** in an array names azResult. Then azResult holds this content: 2441** 2442** <blockquote><pre> 2443** azResult[0] = "Name"; 2444** azResult[1] = "Age"; 2445** azResult[2] = "Alice"; 2446** azResult[3] = "43"; 2447** azResult[4] = "Bob"; 2448** azResult[5] = "28"; 2449** azResult[6] = "Cindy"; 2450** azResult[7] = "21"; 2451** </pre></blockquote>)^ 2452** 2453** ^The sqlite3_get_table() function evaluates one or more 2454** semicolon-separated SQL statements in the zero-terminated UTF-8 2455** string of its 2nd parameter and returns a result table to the 2456** pointer given in its 3rd parameter. 2457** 2458** After the application has finished with the result from sqlite3_get_table(), 2459** it must pass the result table pointer to sqlite3_free_table() in order to 2460** release the memory that was malloced. Because of the way the 2461** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2462** function must not try to call [sqlite3_free()] directly. Only 2463** [sqlite3_free_table()] is able to release the memory properly and safely. 2464** 2465** The sqlite3_get_table() interface is implemented as a wrapper around 2466** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2467** to any internal data structures of SQLite. It uses only the public 2468** interface defined here. As a consequence, errors that occur in the 2469** wrapper layer outside of the internal [sqlite3_exec()] call are not 2470** reflected in subsequent calls to [sqlite3_errcode()] or 2471** [sqlite3_errmsg()]. 2472*/ 2473int sqlite3_get_table( 2474 sqlite3 *db, /* An open database */ 2475 const char *zSql, /* SQL to be evaluated */ 2476 char ***pazResult, /* Results of the query */ 2477 int *pnRow, /* Number of result rows written here */ 2478 int *pnColumn, /* Number of result columns written here */ 2479 char **pzErrmsg /* Error msg written here */ 2480); 2481void sqlite3_free_table(char **result); 2482 2483/* 2484** CAPI3REF: Formatted String Printing Functions 2485** 2486** These routines are work-alikes of the "printf()" family of functions 2487** from the standard C library. 2488** These routines understand most of the common K&R formatting options, 2489** plus some additional non-standard formats, detailed below. 2490** Note that some of the more obscure formatting options from recent 2491** C-library standards are omitted from this implementation. 2492** 2493** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2494** results into memory obtained from [sqlite3_malloc()]. 2495** The strings returned by these two routines should be 2496** released by [sqlite3_free()]. ^Both routines return a 2497** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2498** memory to hold the resulting string. 2499** 2500** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2501** the standard C library. The result is written into the 2502** buffer supplied as the second parameter whose size is given by 2503** the first parameter. Note that the order of the 2504** first two parameters is reversed from snprintf().)^ This is an 2505** historical accident that cannot be fixed without breaking 2506** backwards compatibility. ^(Note also that sqlite3_snprintf() 2507** returns a pointer to its buffer instead of the number of 2508** characters actually written into the buffer.)^ We admit that 2509** the number of characters written would be a more useful return 2510** value but we cannot change the implementation of sqlite3_snprintf() 2511** now without breaking compatibility. 2512** 2513** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2514** guarantees that the buffer is always zero-terminated. ^The first 2515** parameter "n" is the total size of the buffer, including space for 2516** the zero terminator. So the longest string that can be completely 2517** written will be n-1 characters. 2518** 2519** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2520** 2521** These routines all implement some additional formatting 2522** options that are useful for constructing SQL statements. 2523** All of the usual printf() formatting options apply. In addition, there 2524** is are "%q", "%Q", "%w" and "%z" options. 2525** 2526** ^(The %q option works like %s in that it substitutes a nul-terminated 2527** string from the argument list. But %q also doubles every '\'' character. 2528** %q is designed for use inside a string literal.)^ By doubling each '\'' 2529** character it escapes that character and allows it to be inserted into 2530** the string. 2531** 2532** For example, assume the string variable zText contains text as follows: 2533** 2534** <blockquote><pre> 2535** char *zText = "It's a happy day!"; 2536** </pre></blockquote> 2537** 2538** One can use this text in an SQL statement as follows: 2539** 2540** <blockquote><pre> 2541** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2542** sqlite3_exec(db, zSQL, 0, 0, 0); 2543** sqlite3_free(zSQL); 2544** </pre></blockquote> 2545** 2546** Because the %q format string is used, the '\'' character in zText 2547** is escaped and the SQL generated is as follows: 2548** 2549** <blockquote><pre> 2550** INSERT INTO table1 VALUES('It''s a happy day!') 2551** </pre></blockquote> 2552** 2553** This is correct. Had we used %s instead of %q, the generated SQL 2554** would have looked like this: 2555** 2556** <blockquote><pre> 2557** INSERT INTO table1 VALUES('It's a happy day!'); 2558** </pre></blockquote> 2559** 2560** This second example is an SQL syntax error. As a general rule you should 2561** always use %q instead of %s when inserting text into a string literal. 2562** 2563** ^(The %Q option works like %q except it also adds single quotes around 2564** the outside of the total string. Additionally, if the parameter in the 2565** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2566** single quotes).)^ So, for example, one could say: 2567** 2568** <blockquote><pre> 2569** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2570** sqlite3_exec(db, zSQL, 0, 0, 0); 2571** sqlite3_free(zSQL); 2572** </pre></blockquote> 2573** 2574** The code above will render a correct SQL statement in the zSQL 2575** variable even if the zText variable is a NULL pointer. 2576** 2577** ^(The "%w" formatting option is like "%q" except that it expects to 2578** be contained within double-quotes instead of single quotes, and it 2579** escapes the double-quote character instead of the single-quote 2580** character.)^ The "%w" formatting option is intended for safely inserting 2581** table and column names into a constructed SQL statement. 2582** 2583** ^(The "%z" formatting option works like "%s" but with the 2584** addition that after the string has been read and copied into 2585** the result, [sqlite3_free()] is called on the input string.)^ 2586*/ 2587char *sqlite3_mprintf(const char*,...); 2588char *sqlite3_vmprintf(const char*, va_list); 2589char *sqlite3_snprintf(int,char*,const char*, ...); 2590char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2591 2592/* 2593** CAPI3REF: Memory Allocation Subsystem 2594** 2595** The SQLite core uses these three routines for all of its own 2596** internal memory allocation needs. "Core" in the previous sentence 2597** does not include operating-system specific VFS implementation. The 2598** Windows VFS uses native malloc() and free() for some operations. 2599** 2600** ^The sqlite3_malloc() routine returns a pointer to a block 2601** of memory at least N bytes in length, where N is the parameter. 2602** ^If sqlite3_malloc() is unable to obtain sufficient free 2603** memory, it returns a NULL pointer. ^If the parameter N to 2604** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2605** a NULL pointer. 2606** 2607** ^The sqlite3_malloc64(N) routine works just like 2608** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2609** of a signed 32-bit integer. 2610** 2611** ^Calling sqlite3_free() with a pointer previously returned 2612** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2613** that it might be reused. ^The sqlite3_free() routine is 2614** a no-op if is called with a NULL pointer. Passing a NULL pointer 2615** to sqlite3_free() is harmless. After being freed, memory 2616** should neither be read nor written. Even reading previously freed 2617** memory might result in a segmentation fault or other severe error. 2618** Memory corruption, a segmentation fault, or other severe error 2619** might result if sqlite3_free() is called with a non-NULL pointer that 2620** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2621** 2622** ^The sqlite3_realloc(X,N) interface attempts to resize a 2623** prior memory allocation X to be at least N bytes. 2624** ^If the X parameter to sqlite3_realloc(X,N) 2625** is a NULL pointer then its behavior is identical to calling 2626** sqlite3_malloc(N). 2627** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2628** negative then the behavior is exactly the same as calling 2629** sqlite3_free(X). 2630** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2631** of at least N bytes in size or NULL if insufficient memory is available. 2632** ^If M is the size of the prior allocation, then min(N,M) bytes 2633** of the prior allocation are copied into the beginning of buffer returned 2634** by sqlite3_realloc(X,N) and the prior allocation is freed. 2635** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2636** prior allocation is not freed. 2637** 2638** ^The sqlite3_realloc64(X,N) interfaces works the same as 2639** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2640** of a 32-bit signed integer. 2641** 2642** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2643** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2644** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2645** ^The value returned by sqlite3_msize(X) might be larger than the number 2646** of bytes requested when X was allocated. ^If X is a NULL pointer then 2647** sqlite3_msize(X) returns zero. If X points to something that is not 2648** the beginning of memory allocation, or if it points to a formerly 2649** valid memory allocation that has now been freed, then the behavior 2650** of sqlite3_msize(X) is undefined and possibly harmful. 2651** 2652** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2653** sqlite3_malloc64(), and sqlite3_realloc64() 2654** is always aligned to at least an 8 byte boundary, or to a 2655** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2656** option is used. 2657** 2658** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2659** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2660** implementation of these routines to be omitted. That capability 2661** is no longer provided. Only built-in memory allocators can be used. 2662** 2663** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2664** the system malloc() and free() directly when converting 2665** filenames between the UTF-8 encoding used by SQLite 2666** and whatever filename encoding is used by the particular Windows 2667** installation. Memory allocation errors were detected, but 2668** they were reported back as [SQLITE_CANTOPEN] or 2669** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2670** 2671** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2672** must be either NULL or else pointers obtained from a prior 2673** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2674** not yet been released. 2675** 2676** The application must not read or write any part of 2677** a block of memory after it has been released using 2678** [sqlite3_free()] or [sqlite3_realloc()]. 2679*/ 2680void *sqlite3_malloc(int); 2681void *sqlite3_malloc64(sqlite3_uint64); 2682void *sqlite3_realloc(void*, int); 2683void *sqlite3_realloc64(void*, sqlite3_uint64); 2684void sqlite3_free(void*); 2685sqlite3_uint64 sqlite3_msize(void*); 2686 2687/* 2688** CAPI3REF: Memory Allocator Statistics 2689** 2690** SQLite provides these two interfaces for reporting on the status 2691** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2692** routines, which form the built-in memory allocation subsystem. 2693** 2694** ^The [sqlite3_memory_used()] routine returns the number of bytes 2695** of memory currently outstanding (malloced but not freed). 2696** ^The [sqlite3_memory_highwater()] routine returns the maximum 2697** value of [sqlite3_memory_used()] since the high-water mark 2698** was last reset. ^The values returned by [sqlite3_memory_used()] and 2699** [sqlite3_memory_highwater()] include any overhead 2700** added by SQLite in its implementation of [sqlite3_malloc()], 2701** but not overhead added by the any underlying system library 2702** routines that [sqlite3_malloc()] may call. 2703** 2704** ^The memory high-water mark is reset to the current value of 2705** [sqlite3_memory_used()] if and only if the parameter to 2706** [sqlite3_memory_highwater()] is true. ^The value returned 2707** by [sqlite3_memory_highwater(1)] is the high-water mark 2708** prior to the reset. 2709*/ 2710sqlite3_int64 sqlite3_memory_used(void); 2711sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2712 2713/* 2714** CAPI3REF: Pseudo-Random Number Generator 2715** 2716** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2717** select random [ROWID | ROWIDs] when inserting new records into a table that 2718** already uses the largest possible [ROWID]. The PRNG is also used for 2719** the build-in random() and randomblob() SQL functions. This interface allows 2720** applications to access the same PRNG for other purposes. 2721** 2722** ^A call to this routine stores N bytes of randomness into buffer P. 2723** ^The P parameter can be a NULL pointer. 2724** 2725** ^If this routine has not been previously called or if the previous 2726** call had N less than one or a NULL pointer for P, then the PRNG is 2727** seeded using randomness obtained from the xRandomness method of 2728** the default [sqlite3_vfs] object. 2729** ^If the previous call to this routine had an N of 1 or more and a 2730** non-NULL P then the pseudo-randomness is generated 2731** internally and without recourse to the [sqlite3_vfs] xRandomness 2732** method. 2733*/ 2734void sqlite3_randomness(int N, void *P); 2735 2736/* 2737** CAPI3REF: Compile-Time Authorization Callbacks 2738** METHOD: sqlite3 2739** KEYWORDS: {authorizer callback} 2740** 2741** ^This routine registers an authorizer callback with a particular 2742** [database connection], supplied in the first argument. 2743** ^The authorizer callback is invoked as SQL statements are being compiled 2744** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2745** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2746** and [sqlite3_prepare16_v3()]. ^At various 2747** points during the compilation process, as logic is being created 2748** to perform various actions, the authorizer callback is invoked to 2749** see if those actions are allowed. ^The authorizer callback should 2750** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2751** specific action but allow the SQL statement to continue to be 2752** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2753** rejected with an error. ^If the authorizer callback returns 2754** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2755** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2756** the authorizer will fail with an error message. 2757** 2758** When the callback returns [SQLITE_OK], that means the operation 2759** requested is ok. ^When the callback returns [SQLITE_DENY], the 2760** [sqlite3_prepare_v2()] or equivalent call that triggered the 2761** authorizer will fail with an error message explaining that 2762** access is denied. 2763** 2764** ^The first parameter to the authorizer callback is a copy of the third 2765** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2766** to the callback is an integer [SQLITE_COPY | action code] that specifies 2767** the particular action to be authorized. ^The third through sixth parameters 2768** to the callback are either NULL pointers or zero-terminated strings 2769** that contain additional details about the action to be authorized. 2770** Applications must always be prepared to encounter a NULL pointer in any 2771** of the third through the sixth parameters of the authorization callback. 2772** 2773** ^If the action code is [SQLITE_READ] 2774** and the callback returns [SQLITE_IGNORE] then the 2775** [prepared statement] statement is constructed to substitute 2776** a NULL value in place of the table column that would have 2777** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2778** return can be used to deny an untrusted user access to individual 2779** columns of a table. 2780** ^When a table is referenced by a [SELECT] but no column values are 2781** extracted from that table (for example in a query like 2782** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2783** is invoked once for that table with a column name that is an empty string. 2784** ^If the action code is [SQLITE_DELETE] and the callback returns 2785** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2786** [truncate optimization] is disabled and all rows are deleted individually. 2787** 2788** An authorizer is used when [sqlite3_prepare | preparing] 2789** SQL statements from an untrusted source, to ensure that the SQL statements 2790** do not try to access data they are not allowed to see, or that they do not 2791** try to execute malicious statements that damage the database. For 2792** example, an application may allow a user to enter arbitrary 2793** SQL queries for evaluation by a database. But the application does 2794** not want the user to be able to make arbitrary changes to the 2795** database. An authorizer could then be put in place while the 2796** user-entered SQL is being [sqlite3_prepare | prepared] that 2797** disallows everything except [SELECT] statements. 2798** 2799** Applications that need to process SQL from untrusted sources 2800** might also consider lowering resource limits using [sqlite3_limit()] 2801** and limiting database size using the [max_page_count] [PRAGMA] 2802** in addition to using an authorizer. 2803** 2804** ^(Only a single authorizer can be in place on a database connection 2805** at a time. Each call to sqlite3_set_authorizer overrides the 2806** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2807** The authorizer is disabled by default. 2808** 2809** The authorizer callback must not do anything that will modify 2810** the database connection that invoked the authorizer callback. 2811** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2812** database connections for the meaning of "modify" in this paragraph. 2813** 2814** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2815** statement might be re-prepared during [sqlite3_step()] due to a 2816** schema change. Hence, the application should ensure that the 2817** correct authorizer callback remains in place during the [sqlite3_step()]. 2818** 2819** ^Note that the authorizer callback is invoked only during 2820** [sqlite3_prepare()] or its variants. Authorization is not 2821** performed during statement evaluation in [sqlite3_step()], unless 2822** as stated in the previous paragraph, sqlite3_step() invokes 2823** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2824*/ 2825int sqlite3_set_authorizer( 2826 sqlite3*, 2827 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2828 void *pUserData 2829); 2830 2831/* 2832** CAPI3REF: Authorizer Return Codes 2833** 2834** The [sqlite3_set_authorizer | authorizer callback function] must 2835** return either [SQLITE_OK] or one of these two constants in order 2836** to signal SQLite whether or not the action is permitted. See the 2837** [sqlite3_set_authorizer | authorizer documentation] for additional 2838** information. 2839** 2840** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2841** returned from the [sqlite3_vtab_on_conflict()] interface. 2842*/ 2843#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2844#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2845 2846/* 2847** CAPI3REF: Authorizer Action Codes 2848** 2849** The [sqlite3_set_authorizer()] interface registers a callback function 2850** that is invoked to authorize certain SQL statement actions. The 2851** second parameter to the callback is an integer code that specifies 2852** what action is being authorized. These are the integer action codes that 2853** the authorizer callback may be passed. 2854** 2855** These action code values signify what kind of operation is to be 2856** authorized. The 3rd and 4th parameters to the authorization 2857** callback function will be parameters or NULL depending on which of these 2858** codes is used as the second parameter. ^(The 5th parameter to the 2859** authorizer callback is the name of the database ("main", "temp", 2860** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2861** is the name of the inner-most trigger or view that is responsible for 2862** the access attempt or NULL if this access attempt is directly from 2863** top-level SQL code. 2864*/ 2865/******************************************* 3rd ************ 4th ***********/ 2866#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2867#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2868#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2869#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2870#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2871#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2872#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2873#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2874#define SQLITE_DELETE 9 /* Table Name NULL */ 2875#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2876#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2877#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2878#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2879#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2880#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2881#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2882#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2883#define SQLITE_INSERT 18 /* Table Name NULL */ 2884#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2885#define SQLITE_READ 20 /* Table Name Column Name */ 2886#define SQLITE_SELECT 21 /* NULL NULL */ 2887#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2888#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2889#define SQLITE_ATTACH 24 /* Filename NULL */ 2890#define SQLITE_DETACH 25 /* Database Name NULL */ 2891#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2892#define SQLITE_REINDEX 27 /* Index Name NULL */ 2893#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2894#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2895#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2896#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2897#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2898#define SQLITE_COPY 0 /* No longer used */ 2899#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2900 2901/* 2902** CAPI3REF: Tracing And Profiling Functions 2903** METHOD: sqlite3 2904** 2905** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2906** instead of the routines described here. 2907** 2908** These routines register callback functions that can be used for 2909** tracing and profiling the execution of SQL statements. 2910** 2911** ^The callback function registered by sqlite3_trace() is invoked at 2912** various times when an SQL statement is being run by [sqlite3_step()]. 2913** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2914** SQL statement text as the statement first begins executing. 2915** ^(Additional sqlite3_trace() callbacks might occur 2916** as each triggered subprogram is entered. The callbacks for triggers 2917** contain a UTF-8 SQL comment that identifies the trigger.)^ 2918** 2919** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2920** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2921** 2922** ^The callback function registered by sqlite3_profile() is invoked 2923** as each SQL statement finishes. ^The profile callback contains 2924** the original statement text and an estimate of wall-clock time 2925** of how long that statement took to run. ^The profile callback 2926** time is in units of nanoseconds, however the current implementation 2927** is only capable of millisecond resolution so the six least significant 2928** digits in the time are meaningless. Future versions of SQLite 2929** might provide greater resolution on the profiler callback. The 2930** sqlite3_profile() function is considered experimental and is 2931** subject to change in future versions of SQLite. 2932*/ 2933SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2934 void(*xTrace)(void*,const char*), void*); 2935SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2936 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2937 2938/* 2939** CAPI3REF: SQL Trace Event Codes 2940** KEYWORDS: SQLITE_TRACE 2941** 2942** These constants identify classes of events that can be monitored 2943** using the [sqlite3_trace_v2()] tracing logic. The third argument 2944** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2945** the following constants. ^The first argument to the trace callback 2946** is one of the following constants. 2947** 2948** New tracing constants may be added in future releases. 2949** 2950** ^A trace callback has four arguments: xCallback(T,C,P,X). 2951** ^The T argument is one of the integer type codes above. 2952** ^The C argument is a copy of the context pointer passed in as the 2953** fourth argument to [sqlite3_trace_v2()]. 2954** The P and X arguments are pointers whose meanings depend on T. 2955** 2956** <dl> 2957** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2958** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2959** first begins running and possibly at other times during the 2960** execution of the prepared statement, such as at the start of each 2961** trigger subprogram. ^The P argument is a pointer to the 2962** [prepared statement]. ^The X argument is a pointer to a string which 2963** is the unexpanded SQL text of the prepared statement or an SQL comment 2964** that indicates the invocation of a trigger. ^The callback can compute 2965** the same text that would have been returned by the legacy [sqlite3_trace()] 2966** interface by using the X argument when X begins with "--" and invoking 2967** [sqlite3_expanded_sql(P)] otherwise. 2968** 2969** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2970** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2971** information as is provided by the [sqlite3_profile()] callback. 2972** ^The P argument is a pointer to the [prepared statement] and the 2973** X argument points to a 64-bit integer which is the estimated of 2974** the number of nanosecond that the prepared statement took to run. 2975** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2976** 2977** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2978** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2979** statement generates a single row of result. 2980** ^The P argument is a pointer to the [prepared statement] and the 2981** X argument is unused. 2982** 2983** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2984** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2985** connection closes. 2986** ^The P argument is a pointer to the [database connection] object 2987** and the X argument is unused. 2988** </dl> 2989*/ 2990#define SQLITE_TRACE_STMT 0x01 2991#define SQLITE_TRACE_PROFILE 0x02 2992#define SQLITE_TRACE_ROW 0x04 2993#define SQLITE_TRACE_CLOSE 0x08 2994 2995/* 2996** CAPI3REF: SQL Trace Hook 2997** METHOD: sqlite3 2998** 2999** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3000** function X against [database connection] D, using property mask M 3001** and context pointer P. ^If the X callback is 3002** NULL or if the M mask is zero, then tracing is disabled. The 3003** M argument should be the bitwise OR-ed combination of 3004** zero or more [SQLITE_TRACE] constants. 3005** 3006** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3007** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3008** 3009** ^The X callback is invoked whenever any of the events identified by 3010** mask M occur. ^The integer return value from the callback is currently 3011** ignored, though this may change in future releases. Callback 3012** implementations should return zero to ensure future compatibility. 3013** 3014** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3015** ^The T argument is one of the [SQLITE_TRACE] 3016** constants to indicate why the callback was invoked. 3017** ^The C argument is a copy of the context pointer. 3018** The P and X arguments are pointers whose meanings depend on T. 3019** 3020** The sqlite3_trace_v2() interface is intended to replace the legacy 3021** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3022** are deprecated. 3023*/ 3024int sqlite3_trace_v2( 3025 sqlite3*, 3026 unsigned uMask, 3027 int(*xCallback)(unsigned,void*,void*,void*), 3028 void *pCtx 3029); 3030 3031/* 3032** CAPI3REF: Query Progress Callbacks 3033** METHOD: sqlite3 3034** 3035** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3036** function X to be invoked periodically during long running calls to 3037** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3038** database connection D. An example use for this 3039** interface is to keep a GUI updated during a large query. 3040** 3041** ^The parameter P is passed through as the only parameter to the 3042** callback function X. ^The parameter N is the approximate number of 3043** [virtual machine instructions] that are evaluated between successive 3044** invocations of the callback X. ^If N is less than one then the progress 3045** handler is disabled. 3046** 3047** ^Only a single progress handler may be defined at one time per 3048** [database connection]; setting a new progress handler cancels the 3049** old one. ^Setting parameter X to NULL disables the progress handler. 3050** ^The progress handler is also disabled by setting N to a value less 3051** than 1. 3052** 3053** ^If the progress callback returns non-zero, the operation is 3054** interrupted. This feature can be used to implement a 3055** "Cancel" button on a GUI progress dialog box. 3056** 3057** The progress handler callback must not do anything that will modify 3058** the database connection that invoked the progress handler. 3059** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3060** database connections for the meaning of "modify" in this paragraph. 3061** 3062*/ 3063void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3064 3065/* 3066** CAPI3REF: Opening A New Database Connection 3067** CONSTRUCTOR: sqlite3 3068** 3069** ^These routines open an SQLite database file as specified by the 3070** filename argument. ^The filename argument is interpreted as UTF-8 for 3071** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3072** order for sqlite3_open16(). ^(A [database connection] handle is usually 3073** returned in *ppDb, even if an error occurs. The only exception is that 3074** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3075** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3076** object.)^ ^(If the database is opened (and/or created) successfully, then 3077** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3078** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3079** an English language description of the error following a failure of any 3080** of the sqlite3_open() routines. 3081** 3082** ^The default encoding will be UTF-8 for databases created using 3083** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3084** created using sqlite3_open16() will be UTF-16 in the native byte order. 3085** 3086** Whether or not an error occurs when it is opened, resources 3087** associated with the [database connection] handle should be released by 3088** passing it to [sqlite3_close()] when it is no longer required. 3089** 3090** The sqlite3_open_v2() interface works like sqlite3_open() 3091** except that it accepts two additional parameters for additional control 3092** over the new database connection. ^(The flags parameter to 3093** sqlite3_open_v2() can take one of 3094** the following three values, optionally combined with the 3095** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3096** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3097** 3098** <dl> 3099** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3100** <dd>The database is opened in read-only mode. If the database does not 3101** already exist, an error is returned.</dd>)^ 3102** 3103** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3104** <dd>The database is opened for reading and writing if possible, or reading 3105** only if the file is write protected by the operating system. In either 3106** case the database must already exist, otherwise an error is returned.</dd>)^ 3107** 3108** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3109** <dd>The database is opened for reading and writing, and is created if 3110** it does not already exist. This is the behavior that is always used for 3111** sqlite3_open() and sqlite3_open16().</dd>)^ 3112** </dl> 3113** 3114** If the 3rd parameter to sqlite3_open_v2() is not one of the 3115** combinations shown above optionally combined with other 3116** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3117** then the behavior is undefined. 3118** 3119** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3120** opens in the multi-thread [threading mode] as long as the single-thread 3121** mode has not been set at compile-time or start-time. ^If the 3122** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3123** in the serialized [threading mode] unless single-thread was 3124** previously selected at compile-time or start-time. 3125** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3126** eligible to use [shared cache mode], regardless of whether or not shared 3127** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3128** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3129** participate in [shared cache mode] even if it is enabled. 3130** 3131** ^The fourth parameter to sqlite3_open_v2() is the name of the 3132** [sqlite3_vfs] object that defines the operating system interface that 3133** the new database connection should use. ^If the fourth parameter is 3134** a NULL pointer then the default [sqlite3_vfs] object is used. 3135** 3136** ^If the filename is ":memory:", then a private, temporary in-memory database 3137** is created for the connection. ^This in-memory database will vanish when 3138** the database connection is closed. Future versions of SQLite might 3139** make use of additional special filenames that begin with the ":" character. 3140** It is recommended that when a database filename actually does begin with 3141** a ":" character you should prefix the filename with a pathname such as 3142** "./" to avoid ambiguity. 3143** 3144** ^If the filename is an empty string, then a private, temporary 3145** on-disk database will be created. ^This private database will be 3146** automatically deleted as soon as the database connection is closed. 3147** 3148** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3149** 3150** ^If [URI filename] interpretation is enabled, and the filename argument 3151** begins with "file:", then the filename is interpreted as a URI. ^URI 3152** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3153** set in the third argument to sqlite3_open_v2(), or if it has 3154** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3155** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3156** URI filename interpretation is turned off 3157** by default, but future releases of SQLite might enable URI filename 3158** interpretation by default. See "[URI filenames]" for additional 3159** information. 3160** 3161** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3162** authority, then it must be either an empty string or the string 3163** "localhost". ^If the authority is not an empty string or "localhost", an 3164** error is returned to the caller. ^The fragment component of a URI, if 3165** present, is ignored. 3166** 3167** ^SQLite uses the path component of the URI as the name of the disk file 3168** which contains the database. ^If the path begins with a '/' character, 3169** then it is interpreted as an absolute path. ^If the path does not begin 3170** with a '/' (meaning that the authority section is omitted from the URI) 3171** then the path is interpreted as a relative path. 3172** ^(On windows, the first component of an absolute path 3173** is a drive specification (e.g. "C:").)^ 3174** 3175** [[core URI query parameters]] 3176** The query component of a URI may contain parameters that are interpreted 3177** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3178** SQLite and its built-in [VFSes] interpret the 3179** following query parameters: 3180** 3181** <ul> 3182** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3183** a VFS object that provides the operating system interface that should 3184** be used to access the database file on disk. ^If this option is set to 3185** an empty string the default VFS object is used. ^Specifying an unknown 3186** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3187** present, then the VFS specified by the option takes precedence over 3188** the value passed as the fourth parameter to sqlite3_open_v2(). 3189** 3190** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3191** "rwc", or "memory". Attempting to set it to any other value is 3192** an error)^. 3193** ^If "ro" is specified, then the database is opened for read-only 3194** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3195** third argument to sqlite3_open_v2(). ^If the mode option is set to 3196** "rw", then the database is opened for read-write (but not create) 3197** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3198** been set. ^Value "rwc" is equivalent to setting both 3199** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3200** set to "memory" then a pure [in-memory database] that never reads 3201** or writes from disk is used. ^It is an error to specify a value for 3202** the mode parameter that is less restrictive than that specified by 3203** the flags passed in the third parameter to sqlite3_open_v2(). 3204** 3205** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3206** "private". ^Setting it to "shared" is equivalent to setting the 3207** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3208** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3209** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3210** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3211** a URI filename, its value overrides any behavior requested by setting 3212** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3213** 3214** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3215** [powersafe overwrite] property does or does not apply to the 3216** storage media on which the database file resides. 3217** 3218** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3219** which if set disables file locking in rollback journal modes. This 3220** is useful for accessing a database on a filesystem that does not 3221** support locking. Caution: Database corruption might result if two 3222** or more processes write to the same database and any one of those 3223** processes uses nolock=1. 3224** 3225** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3226** parameter that indicates that the database file is stored on 3227** read-only media. ^When immutable is set, SQLite assumes that the 3228** database file cannot be changed, even by a process with higher 3229** privilege, and so the database is opened read-only and all locking 3230** and change detection is disabled. Caution: Setting the immutable 3231** property on a database file that does in fact change can result 3232** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3233** See also: [SQLITE_IOCAP_IMMUTABLE]. 3234** 3235** </ul> 3236** 3237** ^Specifying an unknown parameter in the query component of a URI is not an 3238** error. Future versions of SQLite might understand additional query 3239** parameters. See "[query parameters with special meaning to SQLite]" for 3240** additional information. 3241** 3242** [[URI filename examples]] <h3>URI filename examples</h3> 3243** 3244** <table border="1" align=center cellpadding=5> 3245** <tr><th> URI filenames <th> Results 3246** <tr><td> file:data.db <td> 3247** Open the file "data.db" in the current directory. 3248** <tr><td> file:/home/fred/data.db<br> 3249** file:///home/fred/data.db <br> 3250** file://localhost/home/fred/data.db <br> <td> 3251** Open the database file "/home/fred/data.db". 3252** <tr><td> file://darkstar/home/fred/data.db <td> 3253** An error. "darkstar" is not a recognized authority. 3254** <tr><td style="white-space:nowrap"> 3255** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3256** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3257** C:. Note that the %20 escaping in this example is not strictly 3258** necessary - space characters can be used literally 3259** in URI filenames. 3260** <tr><td> file:data.db?mode=ro&cache=private <td> 3261** Open file "data.db" in the current directory for read-only access. 3262** Regardless of whether or not shared-cache mode is enabled by 3263** default, use a private cache. 3264** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3265** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3266** that uses dot-files in place of posix advisory locking. 3267** <tr><td> file:data.db?mode=readonly <td> 3268** An error. "readonly" is not a valid option for the "mode" parameter. 3269** </table> 3270** 3271** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3272** query components of a URI. A hexadecimal escape sequence consists of a 3273** percent sign - "%" - followed by exactly two hexadecimal digits 3274** specifying an octet value. ^Before the path or query components of a 3275** URI filename are interpreted, they are encoded using UTF-8 and all 3276** hexadecimal escape sequences replaced by a single byte containing the 3277** corresponding octet. If this process generates an invalid UTF-8 encoding, 3278** the results are undefined. 3279** 3280** <b>Note to Windows users:</b> The encoding used for the filename argument 3281** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3282** codepage is currently defined. Filenames containing international 3283** characters must be converted to UTF-8 prior to passing them into 3284** sqlite3_open() or sqlite3_open_v2(). 3285** 3286** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3287** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3288** features that require the use of temporary files may fail. 3289** 3290** See also: [sqlite3_temp_directory] 3291*/ 3292int sqlite3_open( 3293 const char *filename, /* Database filename (UTF-8) */ 3294 sqlite3 **ppDb /* OUT: SQLite db handle */ 3295); 3296int sqlite3_open16( 3297 const void *filename, /* Database filename (UTF-16) */ 3298 sqlite3 **ppDb /* OUT: SQLite db handle */ 3299); 3300int sqlite3_open_v2( 3301 const char *filename, /* Database filename (UTF-8) */ 3302 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3303 int flags, /* Flags */ 3304 const char *zVfs /* Name of VFS module to use */ 3305); 3306 3307/* 3308** CAPI3REF: Obtain Values For URI Parameters 3309** 3310** These are utility routines, useful to VFS implementations, that check 3311** to see if a database file was a URI that contained a specific query 3312** parameter, and if so obtains the value of that query parameter. 3313** 3314** If F is the database filename pointer passed into the xOpen() method of 3315** a VFS implementation when the flags parameter to xOpen() has one or 3316** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3317** P is the name of the query parameter, then 3318** sqlite3_uri_parameter(F,P) returns the value of the P 3319** parameter if it exists or a NULL pointer if P does not appear as a 3320** query parameter on F. If P is a query parameter of F 3321** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3322** a pointer to an empty string. 3323** 3324** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3325** parameter and returns true (1) or false (0) according to the value 3326** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3327** value of query parameter P is one of "yes", "true", or "on" in any 3328** case or if the value begins with a non-zero number. The 3329** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3330** query parameter P is one of "no", "false", or "off" in any case or 3331** if the value begins with a numeric zero. If P is not a query 3332** parameter on F or if the value of P is does not match any of the 3333** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3334** 3335** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3336** 64-bit signed integer and returns that integer, or D if P does not 3337** exist. If the value of P is something other than an integer, then 3338** zero is returned. 3339** 3340** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3341** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3342** is not a database file pathname pointer that SQLite passed into the xOpen 3343** VFS method, then the behavior of this routine is undefined and probably 3344** undesirable. 3345*/ 3346const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3347int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3348sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3349 3350 3351/* 3352** CAPI3REF: Error Codes And Messages 3353** METHOD: sqlite3 3354** 3355** ^If the most recent sqlite3_* API call associated with 3356** [database connection] D failed, then the sqlite3_errcode(D) interface 3357** returns the numeric [result code] or [extended result code] for that 3358** API call. 3359** If the most recent API call was successful, 3360** then the return value from sqlite3_errcode() is undefined. 3361** ^The sqlite3_extended_errcode() 3362** interface is the same except that it always returns the 3363** [extended result code] even when extended result codes are 3364** disabled. 3365** 3366** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3367** text that describes the error, as either UTF-8 or UTF-16 respectively. 3368** ^(Memory to hold the error message string is managed internally. 3369** The application does not need to worry about freeing the result. 3370** However, the error string might be overwritten or deallocated by 3371** subsequent calls to other SQLite interface functions.)^ 3372** 3373** ^The sqlite3_errstr() interface returns the English-language text 3374** that describes the [result code], as UTF-8. 3375** ^(Memory to hold the error message string is managed internally 3376** and must not be freed by the application)^. 3377** 3378** When the serialized [threading mode] is in use, it might be the 3379** case that a second error occurs on a separate thread in between 3380** the time of the first error and the call to these interfaces. 3381** When that happens, the second error will be reported since these 3382** interfaces always report the most recent result. To avoid 3383** this, each thread can obtain exclusive use of the [database connection] D 3384** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3385** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3386** all calls to the interfaces listed here are completed. 3387** 3388** If an interface fails with SQLITE_MISUSE, that means the interface 3389** was invoked incorrectly by the application. In that case, the 3390** error code and message may or may not be set. 3391*/ 3392int sqlite3_errcode(sqlite3 *db); 3393int sqlite3_extended_errcode(sqlite3 *db); 3394const char *sqlite3_errmsg(sqlite3*); 3395const void *sqlite3_errmsg16(sqlite3*); 3396const char *sqlite3_errstr(int); 3397 3398/* 3399** CAPI3REF: Prepared Statement Object 3400** KEYWORDS: {prepared statement} {prepared statements} 3401** 3402** An instance of this object represents a single SQL statement that 3403** has been compiled into binary form and is ready to be evaluated. 3404** 3405** Think of each SQL statement as a separate computer program. The 3406** original SQL text is source code. A prepared statement object 3407** is the compiled object code. All SQL must be converted into a 3408** prepared statement before it can be run. 3409** 3410** The life-cycle of a prepared statement object usually goes like this: 3411** 3412** <ol> 3413** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3414** <li> Bind values to [parameters] using the sqlite3_bind_*() 3415** interfaces. 3416** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3417** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3418** to step 2. Do this zero or more times. 3419** <li> Destroy the object using [sqlite3_finalize()]. 3420** </ol> 3421*/ 3422typedef struct sqlite3_stmt sqlite3_stmt; 3423 3424/* 3425** CAPI3REF: Run-time Limits 3426** METHOD: sqlite3 3427** 3428** ^(This interface allows the size of various constructs to be limited 3429** on a connection by connection basis. The first parameter is the 3430** [database connection] whose limit is to be set or queried. The 3431** second parameter is one of the [limit categories] that define a 3432** class of constructs to be size limited. The third parameter is the 3433** new limit for that construct.)^ 3434** 3435** ^If the new limit is a negative number, the limit is unchanged. 3436** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3437** [limits | hard upper bound] 3438** set at compile-time by a C preprocessor macro called 3439** [limits | SQLITE_MAX_<i>NAME</i>]. 3440** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3441** ^Attempts to increase a limit above its hard upper bound are 3442** silently truncated to the hard upper bound. 3443** 3444** ^Regardless of whether or not the limit was changed, the 3445** [sqlite3_limit()] interface returns the prior value of the limit. 3446** ^Hence, to find the current value of a limit without changing it, 3447** simply invoke this interface with the third parameter set to -1. 3448** 3449** Run-time limits are intended for use in applications that manage 3450** both their own internal database and also databases that are controlled 3451** by untrusted external sources. An example application might be a 3452** web browser that has its own databases for storing history and 3453** separate databases controlled by JavaScript applications downloaded 3454** off the Internet. The internal databases can be given the 3455** large, default limits. Databases managed by external sources can 3456** be given much smaller limits designed to prevent a denial of service 3457** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3458** interface to further control untrusted SQL. The size of the database 3459** created by an untrusted script can be contained using the 3460** [max_page_count] [PRAGMA]. 3461** 3462** New run-time limit categories may be added in future releases. 3463*/ 3464int sqlite3_limit(sqlite3*, int id, int newVal); 3465 3466/* 3467** CAPI3REF: Run-Time Limit Categories 3468** KEYWORDS: {limit category} {*limit categories} 3469** 3470** These constants define various performance limits 3471** that can be lowered at run-time using [sqlite3_limit()]. 3472** The synopsis of the meanings of the various limits is shown below. 3473** Additional information is available at [limits | Limits in SQLite]. 3474** 3475** <dl> 3476** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3477** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3478** 3479** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3480** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3481** 3482** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3483** <dd>The maximum number of columns in a table definition or in the 3484** result set of a [SELECT] or the maximum number of columns in an index 3485** or in an ORDER BY or GROUP BY clause.</dd>)^ 3486** 3487** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3488** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3489** 3490** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3491** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3492** 3493** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3494** <dd>The maximum number of instructions in a virtual machine program 3495** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3496** the equivalent tries to allocate space for more than this many opcodes 3497** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3498** 3499** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3500** <dd>The maximum number of arguments on a function.</dd>)^ 3501** 3502** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3503** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3504** 3505** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3506** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3507** <dd>The maximum length of the pattern argument to the [LIKE] or 3508** [GLOB] operators.</dd>)^ 3509** 3510** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3511** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3512** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3513** 3514** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3515** <dd>The maximum depth of recursion for triggers.</dd>)^ 3516** 3517** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3518** <dd>The maximum number of auxiliary worker threads that a single 3519** [prepared statement] may start.</dd>)^ 3520** </dl> 3521*/ 3522#define SQLITE_LIMIT_LENGTH 0 3523#define SQLITE_LIMIT_SQL_LENGTH 1 3524#define SQLITE_LIMIT_COLUMN 2 3525#define SQLITE_LIMIT_EXPR_DEPTH 3 3526#define SQLITE_LIMIT_COMPOUND_SELECT 4 3527#define SQLITE_LIMIT_VDBE_OP 5 3528#define SQLITE_LIMIT_FUNCTION_ARG 6 3529#define SQLITE_LIMIT_ATTACHED 7 3530#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3531#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3532#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3533#define SQLITE_LIMIT_WORKER_THREADS 11 3534 3535/* 3536** CAPI3REF: Prepare Flags 3537** 3538** These constants define various flags that can be passed into 3539** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3540** [sqlite3_prepare16_v3()] interfaces. 3541** 3542** New flags may be added in future releases of SQLite. 3543** 3544** <dl> 3545** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3546** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3547** that the prepared statement will be retained for a long time and 3548** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3549** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3550** be used just once or at most a few times and then destroyed using 3551** [sqlite3_finalize()] relatively soon. The current implementation acts 3552** on this hint by avoiding the use of [lookaside memory] so as not to 3553** deplete the limited store of lookaside memory. Future versions of 3554** SQLite may act on this hint differently. 3555** </dl> 3556*/ 3557#define SQLITE_PREPARE_PERSISTENT 0x01 3558 3559/* 3560** CAPI3REF: Compiling An SQL Statement 3561** KEYWORDS: {SQL statement compiler} 3562** METHOD: sqlite3 3563** CONSTRUCTOR: sqlite3_stmt 3564** 3565** To execute an SQL statement, it must first be compiled into a byte-code 3566** program using one of these routines. Or, in other words, these routines 3567** are constructors for the [prepared statement] object. 3568** 3569** The preferred routine to use is [sqlite3_prepare_v2()]. The 3570** [sqlite3_prepare()] interface is legacy and should be avoided. 3571** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3572** for special purposes. 3573** 3574** The use of the UTF-8 interfaces is preferred, as SQLite currently 3575** does all parsing using UTF-8. The UTF-16 interfaces are provided 3576** as a convenience. The UTF-16 interfaces work by converting the 3577** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3578** 3579** The first argument, "db", is a [database connection] obtained from a 3580** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3581** [sqlite3_open16()]. The database connection must not have been closed. 3582** 3583** The second argument, "zSql", is the statement to be compiled, encoded 3584** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3585** and sqlite3_prepare_v3() 3586** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3587** and sqlite3_prepare16_v3() use UTF-16. 3588** 3589** ^If the nByte argument is negative, then zSql is read up to the 3590** first zero terminator. ^If nByte is positive, then it is the 3591** number of bytes read from zSql. ^If nByte is zero, then no prepared 3592** statement is generated. 3593** If the caller knows that the supplied string is nul-terminated, then 3594** there is a small performance advantage to passing an nByte parameter that 3595** is the number of bytes in the input string <i>including</i> 3596** the nul-terminator. 3597** 3598** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3599** past the end of the first SQL statement in zSql. These routines only 3600** compile the first statement in zSql, so *pzTail is left pointing to 3601** what remains uncompiled. 3602** 3603** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3604** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3605** to NULL. ^If the input text contains no SQL (if the input is an empty 3606** string or a comment) then *ppStmt is set to NULL. 3607** The calling procedure is responsible for deleting the compiled 3608** SQL statement using [sqlite3_finalize()] after it has finished with it. 3609** ppStmt may not be NULL. 3610** 3611** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3612** otherwise an [error code] is returned. 3613** 3614** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3615** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3616** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3617** are retained for backwards compatibility, but their use is discouraged. 3618** ^In the "vX" interfaces, the prepared statement 3619** that is returned (the [sqlite3_stmt] object) contains a copy of the 3620** original SQL text. This causes the [sqlite3_step()] interface to 3621** behave differently in three ways: 3622** 3623** <ol> 3624** <li> 3625** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3626** always used to do, [sqlite3_step()] will automatically recompile the SQL 3627** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3628** retries will occur before sqlite3_step() gives up and returns an error. 3629** </li> 3630** 3631** <li> 3632** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3633** [error codes] or [extended error codes]. ^The legacy behavior was that 3634** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3635** and the application would have to make a second call to [sqlite3_reset()] 3636** in order to find the underlying cause of the problem. With the "v2" prepare 3637** interfaces, the underlying reason for the error is returned immediately. 3638** </li> 3639** 3640** <li> 3641** ^If the specific value bound to [parameter | host parameter] in the 3642** WHERE clause might influence the choice of query plan for a statement, 3643** then the statement will be automatically recompiled, as if there had been 3644** a schema change, on the first [sqlite3_step()] call following any change 3645** to the [sqlite3_bind_text | bindings] of that [parameter]. 3646** ^The specific value of WHERE-clause [parameter] might influence the 3647** choice of query plan if the parameter is the left-hand side of a [LIKE] 3648** or [GLOB] operator or if the parameter is compared to an indexed column 3649** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3650** </li> 3651** 3652** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3653** the extra prepFlags parameter, which is a bit array consisting of zero or 3654** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3655** sqlite3_prepare_v2() interface works exactly the same as 3656** sqlite3_prepare_v3() with a zero prepFlags parameter. 3657** </ol> 3658*/ 3659int sqlite3_prepare( 3660 sqlite3 *db, /* Database handle */ 3661 const char *zSql, /* SQL statement, UTF-8 encoded */ 3662 int nByte, /* Maximum length of zSql in bytes. */ 3663 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3664 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3665); 3666int sqlite3_prepare_v2( 3667 sqlite3 *db, /* Database handle */ 3668 const char *zSql, /* SQL statement, UTF-8 encoded */ 3669 int nByte, /* Maximum length of zSql in bytes. */ 3670 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3671 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3672); 3673int sqlite3_prepare_v3( 3674 sqlite3 *db, /* Database handle */ 3675 const char *zSql, /* SQL statement, UTF-8 encoded */ 3676 int nByte, /* Maximum length of zSql in bytes. */ 3677 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3678 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3679 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3680); 3681int sqlite3_prepare16( 3682 sqlite3 *db, /* Database handle */ 3683 const void *zSql, /* SQL statement, UTF-16 encoded */ 3684 int nByte, /* Maximum length of zSql in bytes. */ 3685 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3686 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3687); 3688int sqlite3_prepare16_v2( 3689 sqlite3 *db, /* Database handle */ 3690 const void *zSql, /* SQL statement, UTF-16 encoded */ 3691 int nByte, /* Maximum length of zSql in bytes. */ 3692 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3693 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3694); 3695int sqlite3_prepare16_v3( 3696 sqlite3 *db, /* Database handle */ 3697 const void *zSql, /* SQL statement, UTF-16 encoded */ 3698 int nByte, /* Maximum length of zSql in bytes. */ 3699 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3700 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3701 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3702); 3703 3704/* 3705** CAPI3REF: Retrieving Statement SQL 3706** METHOD: sqlite3_stmt 3707** 3708** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3709** SQL text used to create [prepared statement] P if P was 3710** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3711** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3712** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3713** string containing the SQL text of prepared statement P with 3714** [bound parameters] expanded. 3715** 3716** ^(For example, if a prepared statement is created using the SQL 3717** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3718** and parameter :xyz is unbound, then sqlite3_sql() will return 3719** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3720** will return "SELECT 2345,NULL".)^ 3721** 3722** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3723** is available to hold the result, or if the result would exceed the 3724** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3725** 3726** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3727** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3728** option causes sqlite3_expanded_sql() to always return NULL. 3729** 3730** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3731** automatically freed when the prepared statement is finalized. 3732** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3733** is obtained from [sqlite3_malloc()] and must be free by the application 3734** by passing it to [sqlite3_free()]. 3735*/ 3736const char *sqlite3_sql(sqlite3_stmt *pStmt); 3737char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3738 3739/* 3740** CAPI3REF: Determine If An SQL Statement Writes The Database 3741** METHOD: sqlite3_stmt 3742** 3743** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3744** and only if the [prepared statement] X makes no direct changes to 3745** the content of the database file. 3746** 3747** Note that [application-defined SQL functions] or 3748** [virtual tables] might change the database indirectly as a side effect. 3749** ^(For example, if an application defines a function "eval()" that 3750** calls [sqlite3_exec()], then the following SQL statement would 3751** change the database file through side-effects: 3752** 3753** <blockquote><pre> 3754** SELECT eval('DELETE FROM t1') FROM t2; 3755** </pre></blockquote> 3756** 3757** But because the [SELECT] statement does not change the database file 3758** directly, sqlite3_stmt_readonly() would still return true.)^ 3759** 3760** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3761** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3762** since the statements themselves do not actually modify the database but 3763** rather they control the timing of when other statements modify the 3764** database. ^The [ATTACH] and [DETACH] statements also cause 3765** sqlite3_stmt_readonly() to return true since, while those statements 3766** change the configuration of a database connection, they do not make 3767** changes to the content of the database files on disk. 3768** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3769** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3770** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3771** sqlite3_stmt_readonly() returns false for those commands. 3772*/ 3773int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3774 3775/* 3776** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3777** METHOD: sqlite3_stmt 3778** 3779** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3780** [prepared statement] S has been stepped at least once using 3781** [sqlite3_step(S)] but has neither run to completion (returned 3782** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3783** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3784** interface returns false if S is a NULL pointer. If S is not a 3785** NULL pointer and is not a pointer to a valid [prepared statement] 3786** object, then the behavior is undefined and probably undesirable. 3787** 3788** This interface can be used in combination [sqlite3_next_stmt()] 3789** to locate all prepared statements associated with a database 3790** connection that are in need of being reset. This can be used, 3791** for example, in diagnostic routines to search for prepared 3792** statements that are holding a transaction open. 3793*/ 3794int sqlite3_stmt_busy(sqlite3_stmt*); 3795 3796/* 3797** CAPI3REF: Dynamically Typed Value Object 3798** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3799** 3800** SQLite uses the sqlite3_value object to represent all values 3801** that can be stored in a database table. SQLite uses dynamic typing 3802** for the values it stores. ^Values stored in sqlite3_value objects 3803** can be integers, floating point values, strings, BLOBs, or NULL. 3804** 3805** An sqlite3_value object may be either "protected" or "unprotected". 3806** Some interfaces require a protected sqlite3_value. Other interfaces 3807** will accept either a protected or an unprotected sqlite3_value. 3808** Every interface that accepts sqlite3_value arguments specifies 3809** whether or not it requires a protected sqlite3_value. The 3810** [sqlite3_value_dup()] interface can be used to construct a new 3811** protected sqlite3_value from an unprotected sqlite3_value. 3812** 3813** The terms "protected" and "unprotected" refer to whether or not 3814** a mutex is held. An internal mutex is held for a protected 3815** sqlite3_value object but no mutex is held for an unprotected 3816** sqlite3_value object. If SQLite is compiled to be single-threaded 3817** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3818** or if SQLite is run in one of reduced mutex modes 3819** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3820** then there is no distinction between protected and unprotected 3821** sqlite3_value objects and they can be used interchangeably. However, 3822** for maximum code portability it is recommended that applications 3823** still make the distinction between protected and unprotected 3824** sqlite3_value objects even when not strictly required. 3825** 3826** ^The sqlite3_value objects that are passed as parameters into the 3827** implementation of [application-defined SQL functions] are protected. 3828** ^The sqlite3_value object returned by 3829** [sqlite3_column_value()] is unprotected. 3830** Unprotected sqlite3_value objects may only be used as arguments 3831** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3832** [sqlite3_value_dup()]. 3833** The [sqlite3_value_blob | sqlite3_value_type()] family of 3834** interfaces require protected sqlite3_value objects. 3835*/ 3836typedef struct sqlite3_value sqlite3_value; 3837 3838/* 3839** CAPI3REF: SQL Function Context Object 3840** 3841** The context in which an SQL function executes is stored in an 3842** sqlite3_context object. ^A pointer to an sqlite3_context object 3843** is always first parameter to [application-defined SQL functions]. 3844** The application-defined SQL function implementation will pass this 3845** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3846** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3847** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3848** and/or [sqlite3_set_auxdata()]. 3849*/ 3850typedef struct sqlite3_context sqlite3_context; 3851 3852/* 3853** CAPI3REF: Binding Values To Prepared Statements 3854** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3855** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3856** METHOD: sqlite3_stmt 3857** 3858** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3859** literals may be replaced by a [parameter] that matches one of following 3860** templates: 3861** 3862** <ul> 3863** <li> ? 3864** <li> ?NNN 3865** <li> :VVV 3866** <li> @VVV 3867** <li> $VVV 3868** </ul> 3869** 3870** In the templates above, NNN represents an integer literal, 3871** and VVV represents an alphanumeric identifier.)^ ^The values of these 3872** parameters (also called "host parameter names" or "SQL parameters") 3873** can be set using the sqlite3_bind_*() routines defined here. 3874** 3875** ^The first argument to the sqlite3_bind_*() routines is always 3876** a pointer to the [sqlite3_stmt] object returned from 3877** [sqlite3_prepare_v2()] or its variants. 3878** 3879** ^The second argument is the index of the SQL parameter to be set. 3880** ^The leftmost SQL parameter has an index of 1. ^When the same named 3881** SQL parameter is used more than once, second and subsequent 3882** occurrences have the same index as the first occurrence. 3883** ^The index for named parameters can be looked up using the 3884** [sqlite3_bind_parameter_index()] API if desired. ^The index 3885** for "?NNN" parameters is the value of NNN. 3886** ^The NNN value must be between 1 and the [sqlite3_limit()] 3887** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3888** 3889** ^The third argument is the value to bind to the parameter. 3890** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3891** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3892** is ignored and the end result is the same as sqlite3_bind_null(). 3893** 3894** ^(In those routines that have a fourth argument, its value is the 3895** number of bytes in the parameter. To be clear: the value is the 3896** number of <u>bytes</u> in the value, not the number of characters.)^ 3897** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3898** is negative, then the length of the string is 3899** the number of bytes up to the first zero terminator. 3900** If the fourth parameter to sqlite3_bind_blob() is negative, then 3901** the behavior is undefined. 3902** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3903** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3904** that parameter must be the byte offset 3905** where the NUL terminator would occur assuming the string were NUL 3906** terminated. If any NUL characters occur at byte offsets less than 3907** the value of the fourth parameter then the resulting string value will 3908** contain embedded NULs. The result of expressions involving strings 3909** with embedded NULs is undefined. 3910** 3911** ^The fifth argument to the BLOB and string binding interfaces 3912** is a destructor used to dispose of the BLOB or 3913** string after SQLite has finished with it. ^The destructor is called 3914** to dispose of the BLOB or string even if the call to bind API fails. 3915** ^If the fifth argument is 3916** the special value [SQLITE_STATIC], then SQLite assumes that the 3917** information is in static, unmanaged space and does not need to be freed. 3918** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3919** SQLite makes its own private copy of the data immediately, before 3920** the sqlite3_bind_*() routine returns. 3921** 3922** ^The sixth argument to sqlite3_bind_text64() must be one of 3923** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3924** to specify the encoding of the text in the third parameter. If 3925** the sixth argument to sqlite3_bind_text64() is not one of the 3926** allowed values shown above, or if the text encoding is different 3927** from the encoding specified by the sixth parameter, then the behavior 3928** is undefined. 3929** 3930** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3931** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3932** (just an integer to hold its size) while it is being processed. 3933** Zeroblobs are intended to serve as placeholders for BLOBs whose 3934** content is later written using 3935** [sqlite3_blob_open | incremental BLOB I/O] routines. 3936** ^A negative value for the zeroblob results in a zero-length BLOB. 3937** 3938** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3939** [prepared statement] S to have an SQL value of NULL, but to also be 3940** associated with the pointer P of type T. ^D is either a NULL pointer or 3941** a pointer to a destructor function for P. ^SQLite will invoke the 3942** destructor D with a single argument of P when it is finished using 3943** P. The T parameter should be a static string, preferably a string 3944** literal. The sqlite3_bind_pointer() routine is part of the 3945** [pointer passing interface] added for SQLite 3.20.0. 3946** 3947** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3948** for the [prepared statement] or with a prepared statement for which 3949** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3950** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3951** routine is passed a [prepared statement] that has been finalized, the 3952** result is undefined and probably harmful. 3953** 3954** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3955** ^Unbound parameters are interpreted as NULL. 3956** 3957** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3958** [error code] if anything goes wrong. 3959** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3960** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3961** [SQLITE_MAX_LENGTH]. 3962** ^[SQLITE_RANGE] is returned if the parameter 3963** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3964** 3965** See also: [sqlite3_bind_parameter_count()], 3966** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3967*/ 3968int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3969int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3970 void(*)(void*)); 3971int sqlite3_bind_double(sqlite3_stmt*, int, double); 3972int sqlite3_bind_int(sqlite3_stmt*, int, int); 3973int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3974int sqlite3_bind_null(sqlite3_stmt*, int); 3975int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3976int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3977int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3978 void(*)(void*), unsigned char encoding); 3979int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3980int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3981int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3982int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3983 3984/* 3985** CAPI3REF: Number Of SQL Parameters 3986** METHOD: sqlite3_stmt 3987** 3988** ^This routine can be used to find the number of [SQL parameters] 3989** in a [prepared statement]. SQL parameters are tokens of the 3990** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3991** placeholders for values that are [sqlite3_bind_blob | bound] 3992** to the parameters at a later time. 3993** 3994** ^(This routine actually returns the index of the largest (rightmost) 3995** parameter. For all forms except ?NNN, this will correspond to the 3996** number of unique parameters. If parameters of the ?NNN form are used, 3997** there may be gaps in the list.)^ 3998** 3999** See also: [sqlite3_bind_blob|sqlite3_bind()], 4000** [sqlite3_bind_parameter_name()], and 4001** [sqlite3_bind_parameter_index()]. 4002*/ 4003int sqlite3_bind_parameter_count(sqlite3_stmt*); 4004 4005/* 4006** CAPI3REF: Name Of A Host Parameter 4007** METHOD: sqlite3_stmt 4008** 4009** ^The sqlite3_bind_parameter_name(P,N) interface returns 4010** the name of the N-th [SQL parameter] in the [prepared statement] P. 4011** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4012** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4013** respectively. 4014** In other words, the initial ":" or "$" or "@" or "?" 4015** is included as part of the name.)^ 4016** ^Parameters of the form "?" without a following integer have no name 4017** and are referred to as "nameless" or "anonymous parameters". 4018** 4019** ^The first host parameter has an index of 1, not 0. 4020** 4021** ^If the value N is out of range or if the N-th parameter is 4022** nameless, then NULL is returned. ^The returned string is 4023** always in UTF-8 encoding even if the named parameter was 4024** originally specified as UTF-16 in [sqlite3_prepare16()], 4025** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4026** 4027** See also: [sqlite3_bind_blob|sqlite3_bind()], 4028** [sqlite3_bind_parameter_count()], and 4029** [sqlite3_bind_parameter_index()]. 4030*/ 4031const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4032 4033/* 4034** CAPI3REF: Index Of A Parameter With A Given Name 4035** METHOD: sqlite3_stmt 4036** 4037** ^Return the index of an SQL parameter given its name. ^The 4038** index value returned is suitable for use as the second 4039** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4040** is returned if no matching parameter is found. ^The parameter 4041** name must be given in UTF-8 even if the original statement 4042** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4043** [sqlite3_prepare16_v3()]. 4044** 4045** See also: [sqlite3_bind_blob|sqlite3_bind()], 4046** [sqlite3_bind_parameter_count()], and 4047** [sqlite3_bind_parameter_name()]. 4048*/ 4049int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4050 4051/* 4052** CAPI3REF: Reset All Bindings On A Prepared Statement 4053** METHOD: sqlite3_stmt 4054** 4055** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4056** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4057** ^Use this routine to reset all host parameters to NULL. 4058*/ 4059int sqlite3_clear_bindings(sqlite3_stmt*); 4060 4061/* 4062** CAPI3REF: Number Of Columns In A Result Set 4063** METHOD: sqlite3_stmt 4064** 4065** ^Return the number of columns in the result set returned by the 4066** [prepared statement]. ^If this routine returns 0, that means the 4067** [prepared statement] returns no data (for example an [UPDATE]). 4068** ^However, just because this routine returns a positive number does not 4069** mean that one or more rows of data will be returned. ^A SELECT statement 4070** will always have a positive sqlite3_column_count() but depending on the 4071** WHERE clause constraints and the table content, it might return no rows. 4072** 4073** See also: [sqlite3_data_count()] 4074*/ 4075int sqlite3_column_count(sqlite3_stmt *pStmt); 4076 4077/* 4078** CAPI3REF: Column Names In A Result Set 4079** METHOD: sqlite3_stmt 4080** 4081** ^These routines return the name assigned to a particular column 4082** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4083** interface returns a pointer to a zero-terminated UTF-8 string 4084** and sqlite3_column_name16() returns a pointer to a zero-terminated 4085** UTF-16 string. ^The first parameter is the [prepared statement] 4086** that implements the [SELECT] statement. ^The second parameter is the 4087** column number. ^The leftmost column is number 0. 4088** 4089** ^The returned string pointer is valid until either the [prepared statement] 4090** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4091** reprepared by the first call to [sqlite3_step()] for a particular run 4092** or until the next call to 4093** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4094** 4095** ^If sqlite3_malloc() fails during the processing of either routine 4096** (for example during a conversion from UTF-8 to UTF-16) then a 4097** NULL pointer is returned. 4098** 4099** ^The name of a result column is the value of the "AS" clause for 4100** that column, if there is an AS clause. If there is no AS clause 4101** then the name of the column is unspecified and may change from 4102** one release of SQLite to the next. 4103*/ 4104const char *sqlite3_column_name(sqlite3_stmt*, int N); 4105const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4106 4107/* 4108** CAPI3REF: Source Of Data In A Query Result 4109** METHOD: sqlite3_stmt 4110** 4111** ^These routines provide a means to determine the database, table, and 4112** table column that is the origin of a particular result column in 4113** [SELECT] statement. 4114** ^The name of the database or table or column can be returned as 4115** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4116** the database name, the _table_ routines return the table name, and 4117** the origin_ routines return the column name. 4118** ^The returned string is valid until the [prepared statement] is destroyed 4119** using [sqlite3_finalize()] or until the statement is automatically 4120** reprepared by the first call to [sqlite3_step()] for a particular run 4121** or until the same information is requested 4122** again in a different encoding. 4123** 4124** ^The names returned are the original un-aliased names of the 4125** database, table, and column. 4126** 4127** ^The first argument to these interfaces is a [prepared statement]. 4128** ^These functions return information about the Nth result column returned by 4129** the statement, where N is the second function argument. 4130** ^The left-most column is column 0 for these routines. 4131** 4132** ^If the Nth column returned by the statement is an expression or 4133** subquery and is not a column value, then all of these functions return 4134** NULL. ^These routine might also return NULL if a memory allocation error 4135** occurs. ^Otherwise, they return the name of the attached database, table, 4136** or column that query result column was extracted from. 4137** 4138** ^As with all other SQLite APIs, those whose names end with "16" return 4139** UTF-16 encoded strings and the other functions return UTF-8. 4140** 4141** ^These APIs are only available if the library was compiled with the 4142** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4143** 4144** If two or more threads call one or more of these routines against the same 4145** prepared statement and column at the same time then the results are 4146** undefined. 4147** 4148** If two or more threads call one or more 4149** [sqlite3_column_database_name | column metadata interfaces] 4150** for the same [prepared statement] and result column 4151** at the same time then the results are undefined. 4152*/ 4153const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4154const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4155const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4156const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4157const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4158const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4159 4160/* 4161** CAPI3REF: Declared Datatype Of A Query Result 4162** METHOD: sqlite3_stmt 4163** 4164** ^(The first parameter is a [prepared statement]. 4165** If this statement is a [SELECT] statement and the Nth column of the 4166** returned result set of that [SELECT] is a table column (not an 4167** expression or subquery) then the declared type of the table 4168** column is returned.)^ ^If the Nth column of the result set is an 4169** expression or subquery, then a NULL pointer is returned. 4170** ^The returned string is always UTF-8 encoded. 4171** 4172** ^(For example, given the database schema: 4173** 4174** CREATE TABLE t1(c1 VARIANT); 4175** 4176** and the following statement to be compiled: 4177** 4178** SELECT c1 + 1, c1 FROM t1; 4179** 4180** this routine would return the string "VARIANT" for the second result 4181** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4182** 4183** ^SQLite uses dynamic run-time typing. ^So just because a column 4184** is declared to contain a particular type does not mean that the 4185** data stored in that column is of the declared type. SQLite is 4186** strongly typed, but the typing is dynamic not static. ^Type 4187** is associated with individual values, not with the containers 4188** used to hold those values. 4189*/ 4190const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4191const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4192 4193/* 4194** CAPI3REF: Evaluate An SQL Statement 4195** METHOD: sqlite3_stmt 4196** 4197** After a [prepared statement] has been prepared using any of 4198** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4199** or [sqlite3_prepare16_v3()] or one of the legacy 4200** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4201** must be called one or more times to evaluate the statement. 4202** 4203** The details of the behavior of the sqlite3_step() interface depend 4204** on whether the statement was prepared using the newer "vX" interfaces 4205** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4206** [sqlite3_prepare16_v2()] or the older legacy 4207** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4208** new "vX" interface is recommended for new applications but the legacy 4209** interface will continue to be supported. 4210** 4211** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4212** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4213** ^With the "v2" interface, any of the other [result codes] or 4214** [extended result codes] might be returned as well. 4215** 4216** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4217** database locks it needs to do its job. ^If the statement is a [COMMIT] 4218** or occurs outside of an explicit transaction, then you can retry the 4219** statement. If the statement is not a [COMMIT] and occurs within an 4220** explicit transaction then you should rollback the transaction before 4221** continuing. 4222** 4223** ^[SQLITE_DONE] means that the statement has finished executing 4224** successfully. sqlite3_step() should not be called again on this virtual 4225** machine without first calling [sqlite3_reset()] to reset the virtual 4226** machine back to its initial state. 4227** 4228** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4229** is returned each time a new row of data is ready for processing by the 4230** caller. The values may be accessed using the [column access functions]. 4231** sqlite3_step() is called again to retrieve the next row of data. 4232** 4233** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4234** violation) has occurred. sqlite3_step() should not be called again on 4235** the VM. More information may be found by calling [sqlite3_errmsg()]. 4236** ^With the legacy interface, a more specific error code (for example, 4237** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4238** can be obtained by calling [sqlite3_reset()] on the 4239** [prepared statement]. ^In the "v2" interface, 4240** the more specific error code is returned directly by sqlite3_step(). 4241** 4242** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4243** Perhaps it was called on a [prepared statement] that has 4244** already been [sqlite3_finalize | finalized] or on one that had 4245** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4246** be the case that the same database connection is being used by two or 4247** more threads at the same moment in time. 4248** 4249** For all versions of SQLite up to and including 3.6.23.1, a call to 4250** [sqlite3_reset()] was required after sqlite3_step() returned anything 4251** other than [SQLITE_ROW] before any subsequent invocation of 4252** sqlite3_step(). Failure to reset the prepared statement using 4253** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4254** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4255** sqlite3_step() began 4256** calling [sqlite3_reset()] automatically in this circumstance rather 4257** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4258** break because any application that ever receives an SQLITE_MISUSE error 4259** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4260** can be used to restore the legacy behavior. 4261** 4262** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4263** API always returns a generic error code, [SQLITE_ERROR], following any 4264** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4265** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4266** specific [error codes] that better describes the error. 4267** We admit that this is a goofy design. The problem has been fixed 4268** with the "v2" interface. If you prepare all of your SQL statements 4269** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4270** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4271** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4272** then the more specific [error codes] are returned directly 4273** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4274*/ 4275int sqlite3_step(sqlite3_stmt*); 4276 4277/* 4278** CAPI3REF: Number of columns in a result set 4279** METHOD: sqlite3_stmt 4280** 4281** ^The sqlite3_data_count(P) interface returns the number of columns in the 4282** current row of the result set of [prepared statement] P. 4283** ^If prepared statement P does not have results ready to return 4284** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4285** interfaces) then sqlite3_data_count(P) returns 0. 4286** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4287** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4288** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4289** will return non-zero if previous call to [sqlite3_step](P) returned 4290** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4291** where it always returns zero since each step of that multi-step 4292** pragma returns 0 columns of data. 4293** 4294** See also: [sqlite3_column_count()] 4295*/ 4296int sqlite3_data_count(sqlite3_stmt *pStmt); 4297 4298/* 4299** CAPI3REF: Fundamental Datatypes 4300** KEYWORDS: SQLITE_TEXT 4301** 4302** ^(Every value in SQLite has one of five fundamental datatypes: 4303** 4304** <ul> 4305** <li> 64-bit signed integer 4306** <li> 64-bit IEEE floating point number 4307** <li> string 4308** <li> BLOB 4309** <li> NULL 4310** </ul>)^ 4311** 4312** These constants are codes for each of those types. 4313** 4314** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4315** for a completely different meaning. Software that links against both 4316** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4317** SQLITE_TEXT. 4318*/ 4319#define SQLITE_INTEGER 1 4320#define SQLITE_FLOAT 2 4321#define SQLITE_BLOB 4 4322#define SQLITE_NULL 5 4323#ifdef SQLITE_TEXT 4324# undef SQLITE_TEXT 4325#else 4326# define SQLITE_TEXT 3 4327#endif 4328#define SQLITE3_TEXT 3 4329 4330/* 4331** CAPI3REF: Result Values From A Query 4332** KEYWORDS: {column access functions} 4333** METHOD: sqlite3_stmt 4334** 4335** <b>Summary:</b> 4336** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4337** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4338** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4339** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4340** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4341** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4342** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4343** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4344** [sqlite3_value|unprotected sqlite3_value] object. 4345** <tr><td> <td> <td> 4346** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4347** or a UTF-8 TEXT result in bytes 4348** <tr><td><b>sqlite3_column_bytes16 </b> 4349** <td>→ <td>Size of UTF-16 4350** TEXT in bytes 4351** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4352** datatype of the result 4353** </table></blockquote> 4354** 4355** <b>Details:</b> 4356** 4357** ^These routines return information about a single column of the current 4358** result row of a query. ^In every case the first argument is a pointer 4359** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4360** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4361** and the second argument is the index of the column for which information 4362** should be returned. ^The leftmost column of the result set has the index 0. 4363** ^The number of columns in the result can be determined using 4364** [sqlite3_column_count()]. 4365** 4366** If the SQL statement does not currently point to a valid row, or if the 4367** column index is out of range, the result is undefined. 4368** These routines may only be called when the most recent call to 4369** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4370** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4371** If any of these routines are called after [sqlite3_reset()] or 4372** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4373** something other than [SQLITE_ROW], the results are undefined. 4374** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4375** are called from a different thread while any of these routines 4376** are pending, then the results are undefined. 4377** 4378** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4379** each return the value of a result column in a specific data format. If 4380** the result column is not initially in the requested format (for example, 4381** if the query returns an integer but the sqlite3_column_text() interface 4382** is used to extract the value) then an automatic type conversion is performed. 4383** 4384** ^The sqlite3_column_type() routine returns the 4385** [SQLITE_INTEGER | datatype code] for the initial data type 4386** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4387** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4388** The return value of sqlite3_column_type() can be used to decide which 4389** of the first six interface should be used to extract the column value. 4390** The value returned by sqlite3_column_type() is only meaningful if no 4391** automatic type conversions have occurred for the value in question. 4392** After a type conversion, the result of calling sqlite3_column_type() 4393** is undefined, though harmless. Future 4394** versions of SQLite may change the behavior of sqlite3_column_type() 4395** following a type conversion. 4396** 4397** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4398** or sqlite3_column_bytes16() interfaces can be used to determine the size 4399** of that BLOB or string. 4400** 4401** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4402** routine returns the number of bytes in that BLOB or string. 4403** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4404** the string to UTF-8 and then returns the number of bytes. 4405** ^If the result is a numeric value then sqlite3_column_bytes() uses 4406** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4407** the number of bytes in that string. 4408** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4409** 4410** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4411** routine returns the number of bytes in that BLOB or string. 4412** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4413** the string to UTF-16 and then returns the number of bytes. 4414** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4415** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4416** the number of bytes in that string. 4417** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4418** 4419** ^The values returned by [sqlite3_column_bytes()] and 4420** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4421** of the string. ^For clarity: the values returned by 4422** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4423** bytes in the string, not the number of characters. 4424** 4425** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4426** even empty strings, are always zero-terminated. ^The return 4427** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4428** 4429** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4430** [unprotected sqlite3_value] object. In a multithreaded environment, 4431** an unprotected sqlite3_value object may only be used safely with 4432** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4433** If the [unprotected sqlite3_value] object returned by 4434** [sqlite3_column_value()] is used in any other way, including calls 4435** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4436** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4437** Hence, the sqlite3_column_value() interface 4438** is normally only useful within the implementation of 4439** [application-defined SQL functions] or [virtual tables], not within 4440** top-level application code. 4441** 4442** The these routines may attempt to convert the datatype of the result. 4443** ^For example, if the internal representation is FLOAT and a text result 4444** is requested, [sqlite3_snprintf()] is used internally to perform the 4445** conversion automatically. ^(The following table details the conversions 4446** that are applied: 4447** 4448** <blockquote> 4449** <table border="1"> 4450** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4451** 4452** <tr><td> NULL <td> INTEGER <td> Result is 0 4453** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4454** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4455** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4456** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4457** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4458** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4459** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4460** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4461** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4462** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4463** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4464** <tr><td> TEXT <td> BLOB <td> No change 4465** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4466** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4467** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4468** </table> 4469** </blockquote>)^ 4470** 4471** Note that when type conversions occur, pointers returned by prior 4472** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4473** sqlite3_column_text16() may be invalidated. 4474** Type conversions and pointer invalidations might occur 4475** in the following cases: 4476** 4477** <ul> 4478** <li> The initial content is a BLOB and sqlite3_column_text() or 4479** sqlite3_column_text16() is called. A zero-terminator might 4480** need to be added to the string.</li> 4481** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4482** sqlite3_column_text16() is called. The content must be converted 4483** to UTF-16.</li> 4484** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4485** sqlite3_column_text() is called. The content must be converted 4486** to UTF-8.</li> 4487** </ul> 4488** 4489** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4490** not invalidate a prior pointer, though of course the content of the buffer 4491** that the prior pointer references will have been modified. Other kinds 4492** of conversion are done in place when it is possible, but sometimes they 4493** are not possible and in those cases prior pointers are invalidated. 4494** 4495** The safest policy is to invoke these routines 4496** in one of the following ways: 4497** 4498** <ul> 4499** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4500** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4501** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4502** </ul> 4503** 4504** In other words, you should call sqlite3_column_text(), 4505** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4506** into the desired format, then invoke sqlite3_column_bytes() or 4507** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4508** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4509** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4510** with calls to sqlite3_column_bytes(). 4511** 4512** ^The pointers returned are valid until a type conversion occurs as 4513** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4514** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4515** and BLOBs is freed automatically. Do not pass the pointers returned 4516** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4517** [sqlite3_free()]. 4518** 4519** ^(If a memory allocation error occurs during the evaluation of any 4520** of these routines, a default value is returned. The default value 4521** is either the integer 0, the floating point number 0.0, or a NULL 4522** pointer. Subsequent calls to [sqlite3_errcode()] will return 4523** [SQLITE_NOMEM].)^ 4524*/ 4525const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4526double sqlite3_column_double(sqlite3_stmt*, int iCol); 4527int sqlite3_column_int(sqlite3_stmt*, int iCol); 4528sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4529const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4530const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4531sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4532int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4533int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4534int sqlite3_column_type(sqlite3_stmt*, int iCol); 4535 4536/* 4537** CAPI3REF: Destroy A Prepared Statement Object 4538** DESTRUCTOR: sqlite3_stmt 4539** 4540** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4541** ^If the most recent evaluation of the statement encountered no errors 4542** or if the statement is never been evaluated, then sqlite3_finalize() returns 4543** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4544** sqlite3_finalize(S) returns the appropriate [error code] or 4545** [extended error code]. 4546** 4547** ^The sqlite3_finalize(S) routine can be called at any point during 4548** the life cycle of [prepared statement] S: 4549** before statement S is ever evaluated, after 4550** one or more calls to [sqlite3_reset()], or after any call 4551** to [sqlite3_step()] regardless of whether or not the statement has 4552** completed execution. 4553** 4554** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4555** 4556** The application must finalize every [prepared statement] in order to avoid 4557** resource leaks. It is a grievous error for the application to try to use 4558** a prepared statement after it has been finalized. Any use of a prepared 4559** statement after it has been finalized can result in undefined and 4560** undesirable behavior such as segfaults and heap corruption. 4561*/ 4562int sqlite3_finalize(sqlite3_stmt *pStmt); 4563 4564/* 4565** CAPI3REF: Reset A Prepared Statement Object 4566** METHOD: sqlite3_stmt 4567** 4568** The sqlite3_reset() function is called to reset a [prepared statement] 4569** object back to its initial state, ready to be re-executed. 4570** ^Any SQL statement variables that had values bound to them using 4571** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4572** Use [sqlite3_clear_bindings()] to reset the bindings. 4573** 4574** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4575** back to the beginning of its program. 4576** 4577** ^If the most recent call to [sqlite3_step(S)] for the 4578** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4579** or if [sqlite3_step(S)] has never before been called on S, 4580** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4581** 4582** ^If the most recent call to [sqlite3_step(S)] for the 4583** [prepared statement] S indicated an error, then 4584** [sqlite3_reset(S)] returns an appropriate [error code]. 4585** 4586** ^The [sqlite3_reset(S)] interface does not change the values 4587** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4588*/ 4589int sqlite3_reset(sqlite3_stmt *pStmt); 4590 4591/* 4592** CAPI3REF: Create Or Redefine SQL Functions 4593** KEYWORDS: {function creation routines} 4594** KEYWORDS: {application-defined SQL function} 4595** KEYWORDS: {application-defined SQL functions} 4596** METHOD: sqlite3 4597** 4598** ^These functions (collectively known as "function creation routines") 4599** are used to add SQL functions or aggregates or to redefine the behavior 4600** of existing SQL functions or aggregates. The only differences between 4601** these routines are the text encoding expected for 4602** the second parameter (the name of the function being created) 4603** and the presence or absence of a destructor callback for 4604** the application data pointer. 4605** 4606** ^The first parameter is the [database connection] to which the SQL 4607** function is to be added. ^If an application uses more than one database 4608** connection then application-defined SQL functions must be added 4609** to each database connection separately. 4610** 4611** ^The second parameter is the name of the SQL function to be created or 4612** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4613** representation, exclusive of the zero-terminator. ^Note that the name 4614** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4615** ^Any attempt to create a function with a longer name 4616** will result in [SQLITE_MISUSE] being returned. 4617** 4618** ^The third parameter (nArg) 4619** is the number of arguments that the SQL function or 4620** aggregate takes. ^If this parameter is -1, then the SQL function or 4621** aggregate may take any number of arguments between 0 and the limit 4622** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4623** parameter is less than -1 or greater than 127 then the behavior is 4624** undefined. 4625** 4626** ^The fourth parameter, eTextRep, specifies what 4627** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4628** its parameters. The application should set this parameter to 4629** [SQLITE_UTF16LE] if the function implementation invokes 4630** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4631** implementation invokes [sqlite3_value_text16be()] on an input, or 4632** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4633** otherwise. ^The same SQL function may be registered multiple times using 4634** different preferred text encodings, with different implementations for 4635** each encoding. 4636** ^When multiple implementations of the same function are available, SQLite 4637** will pick the one that involves the least amount of data conversion. 4638** 4639** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4640** to signal that the function will always return the same result given 4641** the same inputs within a single SQL statement. Most SQL functions are 4642** deterministic. The built-in [random()] SQL function is an example of a 4643** function that is not deterministic. The SQLite query planner is able to 4644** perform additional optimizations on deterministic functions, so use 4645** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4646** 4647** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4648** function can gain access to this pointer using [sqlite3_user_data()].)^ 4649** 4650** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4651** pointers to C-language functions that implement the SQL function or 4652** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4653** callback only; NULL pointers must be passed as the xStep and xFinal 4654** parameters. ^An aggregate SQL function requires an implementation of xStep 4655** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4656** SQL function or aggregate, pass NULL pointers for all three function 4657** callbacks. 4658** 4659** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4660** then it is destructor for the application data pointer. 4661** The destructor is invoked when the function is deleted, either by being 4662** overloaded or when the database connection closes.)^ 4663** ^The destructor is also invoked if the call to 4664** sqlite3_create_function_v2() fails. 4665** ^When the destructor callback of the tenth parameter is invoked, it 4666** is passed a single argument which is a copy of the application data 4667** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4668** 4669** ^It is permitted to register multiple implementations of the same 4670** functions with the same name but with either differing numbers of 4671** arguments or differing preferred text encodings. ^SQLite will use 4672** the implementation that most closely matches the way in which the 4673** SQL function is used. ^A function implementation with a non-negative 4674** nArg parameter is a better match than a function implementation with 4675** a negative nArg. ^A function where the preferred text encoding 4676** matches the database encoding is a better 4677** match than a function where the encoding is different. 4678** ^A function where the encoding difference is between UTF16le and UTF16be 4679** is a closer match than a function where the encoding difference is 4680** between UTF8 and UTF16. 4681** 4682** ^Built-in functions may be overloaded by new application-defined functions. 4683** 4684** ^An application-defined function is permitted to call other 4685** SQLite interfaces. However, such calls must not 4686** close the database connection nor finalize or reset the prepared 4687** statement in which the function is running. 4688*/ 4689int sqlite3_create_function( 4690 sqlite3 *db, 4691 const char *zFunctionName, 4692 int nArg, 4693 int eTextRep, 4694 void *pApp, 4695 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4696 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4697 void (*xFinal)(sqlite3_context*) 4698); 4699int sqlite3_create_function16( 4700 sqlite3 *db, 4701 const void *zFunctionName, 4702 int nArg, 4703 int eTextRep, 4704 void *pApp, 4705 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4706 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4707 void (*xFinal)(sqlite3_context*) 4708); 4709int sqlite3_create_function_v2( 4710 sqlite3 *db, 4711 const char *zFunctionName, 4712 int nArg, 4713 int eTextRep, 4714 void *pApp, 4715 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4716 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4717 void (*xFinal)(sqlite3_context*), 4718 void(*xDestroy)(void*) 4719); 4720 4721/* 4722** CAPI3REF: Text Encodings 4723** 4724** These constant define integer codes that represent the various 4725** text encodings supported by SQLite. 4726*/ 4727#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4728#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4729#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4730#define SQLITE_UTF16 4 /* Use native byte order */ 4731#define SQLITE_ANY 5 /* Deprecated */ 4732#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4733 4734/* 4735** CAPI3REF: Function Flags 4736** 4737** These constants may be ORed together with the 4738** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4739** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4740** [sqlite3_create_function_v2()]. 4741*/ 4742#define SQLITE_DETERMINISTIC 0x800 4743 4744/* 4745** CAPI3REF: Deprecated Functions 4746** DEPRECATED 4747** 4748** These functions are [deprecated]. In order to maintain 4749** backwards compatibility with older code, these functions continue 4750** to be supported. However, new applications should avoid 4751** the use of these functions. To encourage programmers to avoid 4752** these functions, we will not explain what they do. 4753*/ 4754#ifndef SQLITE_OMIT_DEPRECATED 4755SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4756SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4757SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4758SQLITE_DEPRECATED int sqlite3_global_recover(void); 4759SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4760SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4761 void*,sqlite3_int64); 4762#endif 4763 4764/* 4765** CAPI3REF: Obtaining SQL Values 4766** METHOD: sqlite3_value 4767** 4768** <b>Summary:</b> 4769** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4770** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4771** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4772** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4773** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4774** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4775** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4776** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4777** the native byteorder 4778** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4779** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4780** <tr><td> <td> <td> 4781** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4782** or a UTF-8 TEXT in bytes 4783** <tr><td><b>sqlite3_value_bytes16 </b> 4784** <td>→ <td>Size of UTF-16 4785** TEXT in bytes 4786** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4787** datatype of the value 4788** <tr><td><b>sqlite3_value_numeric_type </b> 4789** <td>→ <td>Best numeric datatype of the value 4790** </table></blockquote> 4791** 4792** <b>Details:</b> 4793** 4794** These routines extract type, size, and content information from 4795** [protected sqlite3_value] objects. Protected sqlite3_value objects 4796** are used to pass parameter information into implementation of 4797** [application-defined SQL functions] and [virtual tables]. 4798** 4799** These routines work only with [protected sqlite3_value] objects. 4800** Any attempt to use these routines on an [unprotected sqlite3_value] 4801** is not threadsafe. 4802** 4803** ^These routines work just like the corresponding [column access functions] 4804** except that these routines take a single [protected sqlite3_value] object 4805** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4806** 4807** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4808** in the native byte-order of the host machine. ^The 4809** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4810** extract UTF-16 strings as big-endian and little-endian respectively. 4811** 4812** ^If [sqlite3_value] object V was initialized 4813** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4814** and if X and Y are strings that compare equal according to strcmp(X,Y), 4815** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4816** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4817** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4818** 4819** ^(The sqlite3_value_type(V) interface returns the 4820** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4821** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4822** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4823** Other interfaces might change the datatype for an sqlite3_value object. 4824** For example, if the datatype is initially SQLITE_INTEGER and 4825** sqlite3_value_text(V) is called to extract a text value for that 4826** integer, then subsequent calls to sqlite3_value_type(V) might return 4827** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4828** occurs is undefined and may change from one release of SQLite to the next. 4829** 4830** ^(The sqlite3_value_numeric_type() interface attempts to apply 4831** numeric affinity to the value. This means that an attempt is 4832** made to convert the value to an integer or floating point. If 4833** such a conversion is possible without loss of information (in other 4834** words, if the value is a string that looks like a number) 4835** then the conversion is performed. Otherwise no conversion occurs. 4836** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4837** 4838** Please pay particular attention to the fact that the pointer returned 4839** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4840** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4841** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4842** or [sqlite3_value_text16()]. 4843** 4844** These routines must be called from the same thread as 4845** the SQL function that supplied the [sqlite3_value*] parameters. 4846*/ 4847const void *sqlite3_value_blob(sqlite3_value*); 4848double sqlite3_value_double(sqlite3_value*); 4849int sqlite3_value_int(sqlite3_value*); 4850sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4851void *sqlite3_value_pointer(sqlite3_value*, const char*); 4852const unsigned char *sqlite3_value_text(sqlite3_value*); 4853const void *sqlite3_value_text16(sqlite3_value*); 4854const void *sqlite3_value_text16le(sqlite3_value*); 4855const void *sqlite3_value_text16be(sqlite3_value*); 4856int sqlite3_value_bytes(sqlite3_value*); 4857int sqlite3_value_bytes16(sqlite3_value*); 4858int sqlite3_value_type(sqlite3_value*); 4859int sqlite3_value_numeric_type(sqlite3_value*); 4860 4861/* 4862** CAPI3REF: Finding The Subtype Of SQL Values 4863** METHOD: sqlite3_value 4864** 4865** The sqlite3_value_subtype(V) function returns the subtype for 4866** an [application-defined SQL function] argument V. The subtype 4867** information can be used to pass a limited amount of context from 4868** one SQL function to another. Use the [sqlite3_result_subtype()] 4869** routine to set the subtype for the return value of an SQL function. 4870*/ 4871unsigned int sqlite3_value_subtype(sqlite3_value*); 4872 4873/* 4874** CAPI3REF: Copy And Free SQL Values 4875** METHOD: sqlite3_value 4876** 4877** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4878** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4879** is a [protected sqlite3_value] object even if the input is not. 4880** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4881** memory allocation fails. 4882** 4883** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4884** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4885** then sqlite3_value_free(V) is a harmless no-op. 4886*/ 4887sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4888void sqlite3_value_free(sqlite3_value*); 4889 4890/* 4891** CAPI3REF: Obtain Aggregate Function Context 4892** METHOD: sqlite3_context 4893** 4894** Implementations of aggregate SQL functions use this 4895** routine to allocate memory for storing their state. 4896** 4897** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4898** for a particular aggregate function, SQLite 4899** allocates N of memory, zeroes out that memory, and returns a pointer 4900** to the new memory. ^On second and subsequent calls to 4901** sqlite3_aggregate_context() for the same aggregate function instance, 4902** the same buffer is returned. Sqlite3_aggregate_context() is normally 4903** called once for each invocation of the xStep callback and then one 4904** last time when the xFinal callback is invoked. ^(When no rows match 4905** an aggregate query, the xStep() callback of the aggregate function 4906** implementation is never called and xFinal() is called exactly once. 4907** In those cases, sqlite3_aggregate_context() might be called for the 4908** first time from within xFinal().)^ 4909** 4910** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4911** when first called if N is less than or equal to zero or if a memory 4912** allocate error occurs. 4913** 4914** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4915** determined by the N parameter on first successful call. Changing the 4916** value of N in subsequent call to sqlite3_aggregate_context() within 4917** the same aggregate function instance will not resize the memory 4918** allocation.)^ Within the xFinal callback, it is customary to set 4919** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4920** pointless memory allocations occur. 4921** 4922** ^SQLite automatically frees the memory allocated by 4923** sqlite3_aggregate_context() when the aggregate query concludes. 4924** 4925** The first parameter must be a copy of the 4926** [sqlite3_context | SQL function context] that is the first parameter 4927** to the xStep or xFinal callback routine that implements the aggregate 4928** function. 4929** 4930** This routine must be called from the same thread in which 4931** the aggregate SQL function is running. 4932*/ 4933void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4934 4935/* 4936** CAPI3REF: User Data For Functions 4937** METHOD: sqlite3_context 4938** 4939** ^The sqlite3_user_data() interface returns a copy of 4940** the pointer that was the pUserData parameter (the 5th parameter) 4941** of the [sqlite3_create_function()] 4942** and [sqlite3_create_function16()] routines that originally 4943** registered the application defined function. 4944** 4945** This routine must be called from the same thread in which 4946** the application-defined function is running. 4947*/ 4948void *sqlite3_user_data(sqlite3_context*); 4949 4950/* 4951** CAPI3REF: Database Connection For Functions 4952** METHOD: sqlite3_context 4953** 4954** ^The sqlite3_context_db_handle() interface returns a copy of 4955** the pointer to the [database connection] (the 1st parameter) 4956** of the [sqlite3_create_function()] 4957** and [sqlite3_create_function16()] routines that originally 4958** registered the application defined function. 4959*/ 4960sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4961 4962/* 4963** CAPI3REF: Function Auxiliary Data 4964** METHOD: sqlite3_context 4965** 4966** These functions may be used by (non-aggregate) SQL functions to 4967** associate metadata with argument values. If the same value is passed to 4968** multiple invocations of the same SQL function during query execution, under 4969** some circumstances the associated metadata may be preserved. An example 4970** of where this might be useful is in a regular-expression matching 4971** function. The compiled version of the regular expression can be stored as 4972** metadata associated with the pattern string. 4973** Then as long as the pattern string remains the same, 4974** the compiled regular expression can be reused on multiple 4975** invocations of the same function. 4976** 4977** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4978** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4979** value to the application-defined function. ^N is zero for the left-most 4980** function argument. ^If there is no metadata 4981** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4982** returns a NULL pointer. 4983** 4984** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4985** argument of the application-defined function. ^Subsequent 4986** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4987** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4988** NULL if the metadata has been discarded. 4989** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4990** SQLite will invoke the destructor function X with parameter P exactly 4991** once, when the metadata is discarded. 4992** SQLite is free to discard the metadata at any time, including: <ul> 4993** <li> ^(when the corresponding function parameter changes)^, or 4994** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4995** SQL statement)^, or 4996** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4997** parameter)^, or 4998** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4999** allocation error occurs.)^ </ul> 5000** 5001** Note the last bullet in particular. The destructor X in 5002** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5003** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5004** should be called near the end of the function implementation and the 5005** function implementation should not make any use of P after 5006** sqlite3_set_auxdata() has been called. 5007** 5008** ^(In practice, metadata is preserved between function calls for 5009** function parameters that are compile-time constants, including literal 5010** values and [parameters] and expressions composed from the same.)^ 5011** 5012** The value of the N parameter to these interfaces should be non-negative. 5013** Future enhancements may make use of negative N values to define new 5014** kinds of function caching behavior. 5015** 5016** These routines must be called from the same thread in which 5017** the SQL function is running. 5018*/ 5019void *sqlite3_get_auxdata(sqlite3_context*, int N); 5020void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5021 5022 5023/* 5024** CAPI3REF: Constants Defining Special Destructor Behavior 5025** 5026** These are special values for the destructor that is passed in as the 5027** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5028** argument is SQLITE_STATIC, it means that the content pointer is constant 5029** and will never change. It does not need to be destroyed. ^The 5030** SQLITE_TRANSIENT value means that the content will likely change in 5031** the near future and that SQLite should make its own private copy of 5032** the content before returning. 5033** 5034** The typedef is necessary to work around problems in certain 5035** C++ compilers. 5036*/ 5037typedef void (*sqlite3_destructor_type)(void*); 5038#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5039#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5040 5041/* 5042** CAPI3REF: Setting The Result Of An SQL Function 5043** METHOD: sqlite3_context 5044** 5045** These routines are used by the xFunc or xFinal callbacks that 5046** implement SQL functions and aggregates. See 5047** [sqlite3_create_function()] and [sqlite3_create_function16()] 5048** for additional information. 5049** 5050** These functions work very much like the [parameter binding] family of 5051** functions used to bind values to host parameters in prepared statements. 5052** Refer to the [SQL parameter] documentation for additional information. 5053** 5054** ^The sqlite3_result_blob() interface sets the result from 5055** an application-defined function to be the BLOB whose content is pointed 5056** to by the second parameter and which is N bytes long where N is the 5057** third parameter. 5058** 5059** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5060** interfaces set the result of the application-defined function to be 5061** a BLOB containing all zero bytes and N bytes in size. 5062** 5063** ^The sqlite3_result_double() interface sets the result from 5064** an application-defined function to be a floating point value specified 5065** by its 2nd argument. 5066** 5067** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5068** cause the implemented SQL function to throw an exception. 5069** ^SQLite uses the string pointed to by the 5070** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5071** as the text of an error message. ^SQLite interprets the error 5072** message string from sqlite3_result_error() as UTF-8. ^SQLite 5073** interprets the string from sqlite3_result_error16() as UTF-16 in native 5074** byte order. ^If the third parameter to sqlite3_result_error() 5075** or sqlite3_result_error16() is negative then SQLite takes as the error 5076** message all text up through the first zero character. 5077** ^If the third parameter to sqlite3_result_error() or 5078** sqlite3_result_error16() is non-negative then SQLite takes that many 5079** bytes (not characters) from the 2nd parameter as the error message. 5080** ^The sqlite3_result_error() and sqlite3_result_error16() 5081** routines make a private copy of the error message text before 5082** they return. Hence, the calling function can deallocate or 5083** modify the text after they return without harm. 5084** ^The sqlite3_result_error_code() function changes the error code 5085** returned by SQLite as a result of an error in a function. ^By default, 5086** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5087** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5088** 5089** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5090** error indicating that a string or BLOB is too long to represent. 5091** 5092** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5093** error indicating that a memory allocation failed. 5094** 5095** ^The sqlite3_result_int() interface sets the return value 5096** of the application-defined function to be the 32-bit signed integer 5097** value given in the 2nd argument. 5098** ^The sqlite3_result_int64() interface sets the return value 5099** of the application-defined function to be the 64-bit signed integer 5100** value given in the 2nd argument. 5101** 5102** ^The sqlite3_result_null() interface sets the return value 5103** of the application-defined function to be NULL. 5104** 5105** ^The sqlite3_result_text(), sqlite3_result_text16(), 5106** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5107** set the return value of the application-defined function to be 5108** a text string which is represented as UTF-8, UTF-16 native byte order, 5109** UTF-16 little endian, or UTF-16 big endian, respectively. 5110** ^The sqlite3_result_text64() interface sets the return value of an 5111** application-defined function to be a text string in an encoding 5112** specified by the fifth (and last) parameter, which must be one 5113** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5114** ^SQLite takes the text result from the application from 5115** the 2nd parameter of the sqlite3_result_text* interfaces. 5116** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5117** is negative, then SQLite takes result text from the 2nd parameter 5118** through the first zero character. 5119** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5120** is non-negative, then as many bytes (not characters) of the text 5121** pointed to by the 2nd parameter are taken as the application-defined 5122** function result. If the 3rd parameter is non-negative, then it 5123** must be the byte offset into the string where the NUL terminator would 5124** appear if the string where NUL terminated. If any NUL characters occur 5125** in the string at a byte offset that is less than the value of the 3rd 5126** parameter, then the resulting string will contain embedded NULs and the 5127** result of expressions operating on strings with embedded NULs is undefined. 5128** ^If the 4th parameter to the sqlite3_result_text* interfaces 5129** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5130** function as the destructor on the text or BLOB result when it has 5131** finished using that result. 5132** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5133** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5134** assumes that the text or BLOB result is in constant space and does not 5135** copy the content of the parameter nor call a destructor on the content 5136** when it has finished using that result. 5137** ^If the 4th parameter to the sqlite3_result_text* interfaces 5138** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5139** then SQLite makes a copy of the result into space obtained 5140** from [sqlite3_malloc()] before it returns. 5141** 5142** ^The sqlite3_result_value() interface sets the result of 5143** the application-defined function to be a copy of the 5144** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5145** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5146** so that the [sqlite3_value] specified in the parameter may change or 5147** be deallocated after sqlite3_result_value() returns without harm. 5148** ^A [protected sqlite3_value] object may always be used where an 5149** [unprotected sqlite3_value] object is required, so either 5150** kind of [sqlite3_value] object can be used with this interface. 5151** 5152** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5153** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5154** also associates the host-language pointer P or type T with that 5155** NULL value such that the pointer can be retrieved within an 5156** [application-defined SQL function] using [sqlite3_value_pointer()]. 5157** ^If the D parameter is not NULL, then it is a pointer to a destructor 5158** for the P parameter. ^SQLite invokes D with P as its only argument 5159** when SQLite is finished with P. The T parameter should be a static 5160** string and preferably a string literal. The sqlite3_result_pointer() 5161** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5162** 5163** If these routines are called from within the different thread 5164** than the one containing the application-defined function that received 5165** the [sqlite3_context] pointer, the results are undefined. 5166*/ 5167void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5168void sqlite3_result_blob64(sqlite3_context*,const void*, 5169 sqlite3_uint64,void(*)(void*)); 5170void sqlite3_result_double(sqlite3_context*, double); 5171void sqlite3_result_error(sqlite3_context*, const char*, int); 5172void sqlite3_result_error16(sqlite3_context*, const void*, int); 5173void sqlite3_result_error_toobig(sqlite3_context*); 5174void sqlite3_result_error_nomem(sqlite3_context*); 5175void sqlite3_result_error_code(sqlite3_context*, int); 5176void sqlite3_result_int(sqlite3_context*, int); 5177void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5178void sqlite3_result_null(sqlite3_context*); 5179void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5180void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5181 void(*)(void*), unsigned char encoding); 5182void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5183void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5184void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5185void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5186void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5187void sqlite3_result_zeroblob(sqlite3_context*, int n); 5188int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5189 5190 5191/* 5192** CAPI3REF: Setting The Subtype Of An SQL Function 5193** METHOD: sqlite3_context 5194** 5195** The sqlite3_result_subtype(C,T) function causes the subtype of 5196** the result from the [application-defined SQL function] with 5197** [sqlite3_context] C to be the value T. Only the lower 8 bits 5198** of the subtype T are preserved in current versions of SQLite; 5199** higher order bits are discarded. 5200** The number of subtype bytes preserved by SQLite might increase 5201** in future releases of SQLite. 5202*/ 5203void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5204 5205/* 5206** CAPI3REF: Define New Collating Sequences 5207** METHOD: sqlite3 5208** 5209** ^These functions add, remove, or modify a [collation] associated 5210** with the [database connection] specified as the first argument. 5211** 5212** ^The name of the collation is a UTF-8 string 5213** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5214** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5215** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5216** considered to be the same name. 5217** 5218** ^(The third argument (eTextRep) must be one of the constants: 5219** <ul> 5220** <li> [SQLITE_UTF8], 5221** <li> [SQLITE_UTF16LE], 5222** <li> [SQLITE_UTF16BE], 5223** <li> [SQLITE_UTF16], or 5224** <li> [SQLITE_UTF16_ALIGNED]. 5225** </ul>)^ 5226** ^The eTextRep argument determines the encoding of strings passed 5227** to the collating function callback, xCallback. 5228** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5229** force strings to be UTF16 with native byte order. 5230** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5231** on an even byte address. 5232** 5233** ^The fourth argument, pArg, is an application data pointer that is passed 5234** through as the first argument to the collating function callback. 5235** 5236** ^The fifth argument, xCallback, is a pointer to the collating function. 5237** ^Multiple collating functions can be registered using the same name but 5238** with different eTextRep parameters and SQLite will use whichever 5239** function requires the least amount of data transformation. 5240** ^If the xCallback argument is NULL then the collating function is 5241** deleted. ^When all collating functions having the same name are deleted, 5242** that collation is no longer usable. 5243** 5244** ^The collating function callback is invoked with a copy of the pArg 5245** application data pointer and with two strings in the encoding specified 5246** by the eTextRep argument. The collating function must return an 5247** integer that is negative, zero, or positive 5248** if the first string is less than, equal to, or greater than the second, 5249** respectively. A collating function must always return the same answer 5250** given the same inputs. If two or more collating functions are registered 5251** to the same collation name (using different eTextRep values) then all 5252** must give an equivalent answer when invoked with equivalent strings. 5253** The collating function must obey the following properties for all 5254** strings A, B, and C: 5255** 5256** <ol> 5257** <li> If A==B then B==A. 5258** <li> If A==B and B==C then A==C. 5259** <li> If A<B THEN B>A. 5260** <li> If A<B and B<C then A<C. 5261** </ol> 5262** 5263** If a collating function fails any of the above constraints and that 5264** collating function is registered and used, then the behavior of SQLite 5265** is undefined. 5266** 5267** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5268** with the addition that the xDestroy callback is invoked on pArg when 5269** the collating function is deleted. 5270** ^Collating functions are deleted when they are overridden by later 5271** calls to the collation creation functions or when the 5272** [database connection] is closed using [sqlite3_close()]. 5273** 5274** ^The xDestroy callback is <u>not</u> called if the 5275** sqlite3_create_collation_v2() function fails. Applications that invoke 5276** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5277** check the return code and dispose of the application data pointer 5278** themselves rather than expecting SQLite to deal with it for them. 5279** This is different from every other SQLite interface. The inconsistency 5280** is unfortunate but cannot be changed without breaking backwards 5281** compatibility. 5282** 5283** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5284*/ 5285int sqlite3_create_collation( 5286 sqlite3*, 5287 const char *zName, 5288 int eTextRep, 5289 void *pArg, 5290 int(*xCompare)(void*,int,const void*,int,const void*) 5291); 5292int sqlite3_create_collation_v2( 5293 sqlite3*, 5294 const char *zName, 5295 int eTextRep, 5296 void *pArg, 5297 int(*xCompare)(void*,int,const void*,int,const void*), 5298 void(*xDestroy)(void*) 5299); 5300int sqlite3_create_collation16( 5301 sqlite3*, 5302 const void *zName, 5303 int eTextRep, 5304 void *pArg, 5305 int(*xCompare)(void*,int,const void*,int,const void*) 5306); 5307 5308/* 5309** CAPI3REF: Collation Needed Callbacks 5310** METHOD: sqlite3 5311** 5312** ^To avoid having to register all collation sequences before a database 5313** can be used, a single callback function may be registered with the 5314** [database connection] to be invoked whenever an undefined collation 5315** sequence is required. 5316** 5317** ^If the function is registered using the sqlite3_collation_needed() API, 5318** then it is passed the names of undefined collation sequences as strings 5319** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5320** the names are passed as UTF-16 in machine native byte order. 5321** ^A call to either function replaces the existing collation-needed callback. 5322** 5323** ^(When the callback is invoked, the first argument passed is a copy 5324** of the second argument to sqlite3_collation_needed() or 5325** sqlite3_collation_needed16(). The second argument is the database 5326** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5327** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5328** sequence function required. The fourth parameter is the name of the 5329** required collation sequence.)^ 5330** 5331** The callback function should register the desired collation using 5332** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5333** [sqlite3_create_collation_v2()]. 5334*/ 5335int sqlite3_collation_needed( 5336 sqlite3*, 5337 void*, 5338 void(*)(void*,sqlite3*,int eTextRep,const char*) 5339); 5340int sqlite3_collation_needed16( 5341 sqlite3*, 5342 void*, 5343 void(*)(void*,sqlite3*,int eTextRep,const void*) 5344); 5345 5346#ifdef SQLITE_HAS_CODEC 5347/* 5348** Specify the key for an encrypted database. This routine should be 5349** called right after sqlite3_open(). 5350** 5351** The code to implement this API is not available in the public release 5352** of SQLite. 5353*/ 5354int sqlite3_key( 5355 sqlite3 *db, /* Database to be rekeyed */ 5356 const void *pKey, int nKey /* The key */ 5357); 5358int sqlite3_key_v2( 5359 sqlite3 *db, /* Database to be rekeyed */ 5360 const char *zDbName, /* Name of the database */ 5361 const void *pKey, int nKey /* The key */ 5362); 5363 5364/* 5365** Change the key on an open database. If the current database is not 5366** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5367** database is decrypted. 5368** 5369** The code to implement this API is not available in the public release 5370** of SQLite. 5371*/ 5372int sqlite3_rekey( 5373 sqlite3 *db, /* Database to be rekeyed */ 5374 const void *pKey, int nKey /* The new key */ 5375); 5376int sqlite3_rekey_v2( 5377 sqlite3 *db, /* Database to be rekeyed */ 5378 const char *zDbName, /* Name of the database */ 5379 const void *pKey, int nKey /* The new key */ 5380); 5381 5382/* 5383** Specify the activation key for a SEE database. Unless 5384** activated, none of the SEE routines will work. 5385*/ 5386void sqlite3_activate_see( 5387 const char *zPassPhrase /* Activation phrase */ 5388); 5389#endif 5390 5391#ifdef SQLITE_ENABLE_CEROD 5392/* 5393** Specify the activation key for a CEROD database. Unless 5394** activated, none of the CEROD routines will work. 5395*/ 5396void sqlite3_activate_cerod( 5397 const char *zPassPhrase /* Activation phrase */ 5398); 5399#endif 5400 5401/* 5402** CAPI3REF: Suspend Execution For A Short Time 5403** 5404** The sqlite3_sleep() function causes the current thread to suspend execution 5405** for at least a number of milliseconds specified in its parameter. 5406** 5407** If the operating system does not support sleep requests with 5408** millisecond time resolution, then the time will be rounded up to 5409** the nearest second. The number of milliseconds of sleep actually 5410** requested from the operating system is returned. 5411** 5412** ^SQLite implements this interface by calling the xSleep() 5413** method of the default [sqlite3_vfs] object. If the xSleep() method 5414** of the default VFS is not implemented correctly, or not implemented at 5415** all, then the behavior of sqlite3_sleep() may deviate from the description 5416** in the previous paragraphs. 5417*/ 5418int sqlite3_sleep(int); 5419 5420/* 5421** CAPI3REF: Name Of The Folder Holding Temporary Files 5422** 5423** ^(If this global variable is made to point to a string which is 5424** the name of a folder (a.k.a. directory), then all temporary files 5425** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5426** will be placed in that directory.)^ ^If this variable 5427** is a NULL pointer, then SQLite performs a search for an appropriate 5428** temporary file directory. 5429** 5430** Applications are strongly discouraged from using this global variable. 5431** It is required to set a temporary folder on Windows Runtime (WinRT). 5432** But for all other platforms, it is highly recommended that applications 5433** neither read nor write this variable. This global variable is a relic 5434** that exists for backwards compatibility of legacy applications and should 5435** be avoided in new projects. 5436** 5437** It is not safe to read or modify this variable in more than one 5438** thread at a time. It is not safe to read or modify this variable 5439** if a [database connection] is being used at the same time in a separate 5440** thread. 5441** It is intended that this variable be set once 5442** as part of process initialization and before any SQLite interface 5443** routines have been called and that this variable remain unchanged 5444** thereafter. 5445** 5446** ^The [temp_store_directory pragma] may modify this variable and cause 5447** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5448** the [temp_store_directory pragma] always assumes that any string 5449** that this variable points to is held in memory obtained from 5450** [sqlite3_malloc] and the pragma may attempt to free that memory 5451** using [sqlite3_free]. 5452** Hence, if this variable is modified directly, either it should be 5453** made NULL or made to point to memory obtained from [sqlite3_malloc] 5454** or else the use of the [temp_store_directory pragma] should be avoided. 5455** Except when requested by the [temp_store_directory pragma], SQLite 5456** does not free the memory that sqlite3_temp_directory points to. If 5457** the application wants that memory to be freed, it must do 5458** so itself, taking care to only do so after all [database connection] 5459** objects have been destroyed. 5460** 5461** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5462** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5463** features that require the use of temporary files may fail. Here is an 5464** example of how to do this using C++ with the Windows Runtime: 5465** 5466** <blockquote><pre> 5467** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5468** TemporaryFolder->Path->Data(); 5469** char zPathBuf[MAX_PATH + 1]; 5470** memset(zPathBuf, 0, sizeof(zPathBuf)); 5471** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5472** NULL, NULL); 5473** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5474** </pre></blockquote> 5475*/ 5476SQLITE_EXTERN char *sqlite3_temp_directory; 5477 5478/* 5479** CAPI3REF: Name Of The Folder Holding Database Files 5480** 5481** ^(If this global variable is made to point to a string which is 5482** the name of a folder (a.k.a. directory), then all database files 5483** specified with a relative pathname and created or accessed by 5484** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5485** to be relative to that directory.)^ ^If this variable is a NULL 5486** pointer, then SQLite assumes that all database files specified 5487** with a relative pathname are relative to the current directory 5488** for the process. Only the windows VFS makes use of this global 5489** variable; it is ignored by the unix VFS. 5490** 5491** Changing the value of this variable while a database connection is 5492** open can result in a corrupt database. 5493** 5494** It is not safe to read or modify this variable in more than one 5495** thread at a time. It is not safe to read or modify this variable 5496** if a [database connection] is being used at the same time in a separate 5497** thread. 5498** It is intended that this variable be set once 5499** as part of process initialization and before any SQLite interface 5500** routines have been called and that this variable remain unchanged 5501** thereafter. 5502** 5503** ^The [data_store_directory pragma] may modify this variable and cause 5504** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5505** the [data_store_directory pragma] always assumes that any string 5506** that this variable points to is held in memory obtained from 5507** [sqlite3_malloc] and the pragma may attempt to free that memory 5508** using [sqlite3_free]. 5509** Hence, if this variable is modified directly, either it should be 5510** made NULL or made to point to memory obtained from [sqlite3_malloc] 5511** or else the use of the [data_store_directory pragma] should be avoided. 5512*/ 5513SQLITE_EXTERN char *sqlite3_data_directory; 5514 5515/* 5516** CAPI3REF: Test For Auto-Commit Mode 5517** KEYWORDS: {autocommit mode} 5518** METHOD: sqlite3 5519** 5520** ^The sqlite3_get_autocommit() interface returns non-zero or 5521** zero if the given database connection is or is not in autocommit mode, 5522** respectively. ^Autocommit mode is on by default. 5523** ^Autocommit mode is disabled by a [BEGIN] statement. 5524** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5525** 5526** If certain kinds of errors occur on a statement within a multi-statement 5527** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5528** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5529** transaction might be rolled back automatically. The only way to 5530** find out whether SQLite automatically rolled back the transaction after 5531** an error is to use this function. 5532** 5533** If another thread changes the autocommit status of the database 5534** connection while this routine is running, then the return value 5535** is undefined. 5536*/ 5537int sqlite3_get_autocommit(sqlite3*); 5538 5539/* 5540** CAPI3REF: Find The Database Handle Of A Prepared Statement 5541** METHOD: sqlite3_stmt 5542** 5543** ^The sqlite3_db_handle interface returns the [database connection] handle 5544** to which a [prepared statement] belongs. ^The [database connection] 5545** returned by sqlite3_db_handle is the same [database connection] 5546** that was the first argument 5547** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5548** create the statement in the first place. 5549*/ 5550sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5551 5552/* 5553** CAPI3REF: Return The Filename For A Database Connection 5554** METHOD: sqlite3 5555** 5556** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5557** associated with database N of connection D. ^The main database file 5558** has the name "main". If there is no attached database N on the database 5559** connection D, or if database N is a temporary or in-memory database, then 5560** a NULL pointer is returned. 5561** 5562** ^The filename returned by this function is the output of the 5563** xFullPathname method of the [VFS]. ^In other words, the filename 5564** will be an absolute pathname, even if the filename used 5565** to open the database originally was a URI or relative pathname. 5566*/ 5567const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5568 5569/* 5570** CAPI3REF: Determine if a database is read-only 5571** METHOD: sqlite3 5572** 5573** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5574** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5575** the name of a database on connection D. 5576*/ 5577int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5578 5579/* 5580** CAPI3REF: Find the next prepared statement 5581** METHOD: sqlite3 5582** 5583** ^This interface returns a pointer to the next [prepared statement] after 5584** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5585** then this interface returns a pointer to the first prepared statement 5586** associated with the database connection pDb. ^If no prepared statement 5587** satisfies the conditions of this routine, it returns NULL. 5588** 5589** The [database connection] pointer D in a call to 5590** [sqlite3_next_stmt(D,S)] must refer to an open database 5591** connection and in particular must not be a NULL pointer. 5592*/ 5593sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5594 5595/* 5596** CAPI3REF: Commit And Rollback Notification Callbacks 5597** METHOD: sqlite3 5598** 5599** ^The sqlite3_commit_hook() interface registers a callback 5600** function to be invoked whenever a transaction is [COMMIT | committed]. 5601** ^Any callback set by a previous call to sqlite3_commit_hook() 5602** for the same database connection is overridden. 5603** ^The sqlite3_rollback_hook() interface registers a callback 5604** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5605** ^Any callback set by a previous call to sqlite3_rollback_hook() 5606** for the same database connection is overridden. 5607** ^The pArg argument is passed through to the callback. 5608** ^If the callback on a commit hook function returns non-zero, 5609** then the commit is converted into a rollback. 5610** 5611** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5612** return the P argument from the previous call of the same function 5613** on the same [database connection] D, or NULL for 5614** the first call for each function on D. 5615** 5616** The commit and rollback hook callbacks are not reentrant. 5617** The callback implementation must not do anything that will modify 5618** the database connection that invoked the callback. Any actions 5619** to modify the database connection must be deferred until after the 5620** completion of the [sqlite3_step()] call that triggered the commit 5621** or rollback hook in the first place. 5622** Note that running any other SQL statements, including SELECT statements, 5623** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5624** the database connections for the meaning of "modify" in this paragraph. 5625** 5626** ^Registering a NULL function disables the callback. 5627** 5628** ^When the commit hook callback routine returns zero, the [COMMIT] 5629** operation is allowed to continue normally. ^If the commit hook 5630** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5631** ^The rollback hook is invoked on a rollback that results from a commit 5632** hook returning non-zero, just as it would be with any other rollback. 5633** 5634** ^For the purposes of this API, a transaction is said to have been 5635** rolled back if an explicit "ROLLBACK" statement is executed, or 5636** an error or constraint causes an implicit rollback to occur. 5637** ^The rollback callback is not invoked if a transaction is 5638** automatically rolled back because the database connection is closed. 5639** 5640** See also the [sqlite3_update_hook()] interface. 5641*/ 5642void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5643void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5644 5645/* 5646** CAPI3REF: Data Change Notification Callbacks 5647** METHOD: sqlite3 5648** 5649** ^The sqlite3_update_hook() interface registers a callback function 5650** with the [database connection] identified by the first argument 5651** to be invoked whenever a row is updated, inserted or deleted in 5652** a [rowid table]. 5653** ^Any callback set by a previous call to this function 5654** for the same database connection is overridden. 5655** 5656** ^The second argument is a pointer to the function to invoke when a 5657** row is updated, inserted or deleted in a rowid table. 5658** ^The first argument to the callback is a copy of the third argument 5659** to sqlite3_update_hook(). 5660** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5661** or [SQLITE_UPDATE], depending on the operation that caused the callback 5662** to be invoked. 5663** ^The third and fourth arguments to the callback contain pointers to the 5664** database and table name containing the affected row. 5665** ^The final callback parameter is the [rowid] of the row. 5666** ^In the case of an update, this is the [rowid] after the update takes place. 5667** 5668** ^(The update hook is not invoked when internal system tables are 5669** modified (i.e. sqlite_master and sqlite_sequence).)^ 5670** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5671** 5672** ^In the current implementation, the update hook 5673** is not invoked when conflicting rows are deleted because of an 5674** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5675** invoked when rows are deleted using the [truncate optimization]. 5676** The exceptions defined in this paragraph might change in a future 5677** release of SQLite. 5678** 5679** The update hook implementation must not do anything that will modify 5680** the database connection that invoked the update hook. Any actions 5681** to modify the database connection must be deferred until after the 5682** completion of the [sqlite3_step()] call that triggered the update hook. 5683** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5684** database connections for the meaning of "modify" in this paragraph. 5685** 5686** ^The sqlite3_update_hook(D,C,P) function 5687** returns the P argument from the previous call 5688** on the same [database connection] D, or NULL for 5689** the first call on D. 5690** 5691** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5692** and [sqlite3_preupdate_hook()] interfaces. 5693*/ 5694void *sqlite3_update_hook( 5695 sqlite3*, 5696 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5697 void* 5698); 5699 5700/* 5701** CAPI3REF: Enable Or Disable Shared Pager Cache 5702** 5703** ^(This routine enables or disables the sharing of the database cache 5704** and schema data structures between [database connection | connections] 5705** to the same database. Sharing is enabled if the argument is true 5706** and disabled if the argument is false.)^ 5707** 5708** ^Cache sharing is enabled and disabled for an entire process. 5709** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5710** In prior versions of SQLite, 5711** sharing was enabled or disabled for each thread separately. 5712** 5713** ^(The cache sharing mode set by this interface effects all subsequent 5714** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5715** Existing database connections continue use the sharing mode 5716** that was in effect at the time they were opened.)^ 5717** 5718** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5719** successfully. An [error code] is returned otherwise.)^ 5720** 5721** ^Shared cache is disabled by default. But this might change in 5722** future releases of SQLite. Applications that care about shared 5723** cache setting should set it explicitly. 5724** 5725** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5726** and will always return SQLITE_MISUSE. On those systems, 5727** shared cache mode should be enabled per-database connection via 5728** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5729** 5730** This interface is threadsafe on processors where writing a 5731** 32-bit integer is atomic. 5732** 5733** See Also: [SQLite Shared-Cache Mode] 5734*/ 5735int sqlite3_enable_shared_cache(int); 5736 5737/* 5738** CAPI3REF: Attempt To Free Heap Memory 5739** 5740** ^The sqlite3_release_memory() interface attempts to free N bytes 5741** of heap memory by deallocating non-essential memory allocations 5742** held by the database library. Memory used to cache database 5743** pages to improve performance is an example of non-essential memory. 5744** ^sqlite3_release_memory() returns the number of bytes actually freed, 5745** which might be more or less than the amount requested. 5746** ^The sqlite3_release_memory() routine is a no-op returning zero 5747** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5748** 5749** See also: [sqlite3_db_release_memory()] 5750*/ 5751int sqlite3_release_memory(int); 5752 5753/* 5754** CAPI3REF: Free Memory Used By A Database Connection 5755** METHOD: sqlite3 5756** 5757** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5758** memory as possible from database connection D. Unlike the 5759** [sqlite3_release_memory()] interface, this interface is in effect even 5760** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5761** omitted. 5762** 5763** See also: [sqlite3_release_memory()] 5764*/ 5765int sqlite3_db_release_memory(sqlite3*); 5766 5767/* 5768** CAPI3REF: Impose A Limit On Heap Size 5769** 5770** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5771** soft limit on the amount of heap memory that may be allocated by SQLite. 5772** ^SQLite strives to keep heap memory utilization below the soft heap 5773** limit by reducing the number of pages held in the page cache 5774** as heap memory usages approaches the limit. 5775** ^The soft heap limit is "soft" because even though SQLite strives to stay 5776** below the limit, it will exceed the limit rather than generate 5777** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5778** is advisory only. 5779** 5780** ^The return value from sqlite3_soft_heap_limit64() is the size of 5781** the soft heap limit prior to the call, or negative in the case of an 5782** error. ^If the argument N is negative 5783** then no change is made to the soft heap limit. Hence, the current 5784** size of the soft heap limit can be determined by invoking 5785** sqlite3_soft_heap_limit64() with a negative argument. 5786** 5787** ^If the argument N is zero then the soft heap limit is disabled. 5788** 5789** ^(The soft heap limit is not enforced in the current implementation 5790** if one or more of following conditions are true: 5791** 5792** <ul> 5793** <li> The soft heap limit is set to zero. 5794** <li> Memory accounting is disabled using a combination of the 5795** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5796** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5797** <li> An alternative page cache implementation is specified using 5798** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5799** <li> The page cache allocates from its own memory pool supplied 5800** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5801** from the heap. 5802** </ul>)^ 5803** 5804** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5805** the soft heap limit is enforced 5806** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5807** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5808** the soft heap limit is enforced on every memory allocation. Without 5809** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5810** when memory is allocated by the page cache. Testing suggests that because 5811** the page cache is the predominate memory user in SQLite, most 5812** applications will achieve adequate soft heap limit enforcement without 5813** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5814** 5815** The circumstances under which SQLite will enforce the soft heap limit may 5816** changes in future releases of SQLite. 5817*/ 5818sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5819 5820/* 5821** CAPI3REF: Deprecated Soft Heap Limit Interface 5822** DEPRECATED 5823** 5824** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5825** interface. This routine is provided for historical compatibility 5826** only. All new applications should use the 5827** [sqlite3_soft_heap_limit64()] interface rather than this one. 5828*/ 5829SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5830 5831 5832/* 5833** CAPI3REF: Extract Metadata About A Column Of A Table 5834** METHOD: sqlite3 5835** 5836** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5837** information about column C of table T in database D 5838** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5839** interface returns SQLITE_OK and fills in the non-NULL pointers in 5840** the final five arguments with appropriate values if the specified 5841** column exists. ^The sqlite3_table_column_metadata() interface returns 5842** SQLITE_ERROR and if the specified column does not exist. 5843** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5844** NULL pointer, then this routine simply checks for the existence of the 5845** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5846** does not. If the table name parameter T in a call to 5847** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5848** undefined behavior. 5849** 5850** ^The column is identified by the second, third and fourth parameters to 5851** this function. ^(The second parameter is either the name of the database 5852** (i.e. "main", "temp", or an attached database) containing the specified 5853** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5854** for the table using the same algorithm used by the database engine to 5855** resolve unqualified table references. 5856** 5857** ^The third and fourth parameters to this function are the table and column 5858** name of the desired column, respectively. 5859** 5860** ^Metadata is returned by writing to the memory locations passed as the 5th 5861** and subsequent parameters to this function. ^Any of these arguments may be 5862** NULL, in which case the corresponding element of metadata is omitted. 5863** 5864** ^(<blockquote> 5865** <table border="1"> 5866** <tr><th> Parameter <th> Output<br>Type <th> Description 5867** 5868** <tr><td> 5th <td> const char* <td> Data type 5869** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5870** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5871** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5872** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5873** </table> 5874** </blockquote>)^ 5875** 5876** ^The memory pointed to by the character pointers returned for the 5877** declaration type and collation sequence is valid until the next 5878** call to any SQLite API function. 5879** 5880** ^If the specified table is actually a view, an [error code] is returned. 5881** 5882** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5883** is not a [WITHOUT ROWID] table and an 5884** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5885** parameters are set for the explicitly declared column. ^(If there is no 5886** [INTEGER PRIMARY KEY] column, then the outputs 5887** for the [rowid] are set as follows: 5888** 5889** <pre> 5890** data type: "INTEGER" 5891** collation sequence: "BINARY" 5892** not null: 0 5893** primary key: 1 5894** auto increment: 0 5895** </pre>)^ 5896** 5897** ^This function causes all database schemas to be read from disk and 5898** parsed, if that has not already been done, and returns an error if 5899** any errors are encountered while loading the schema. 5900*/ 5901int sqlite3_table_column_metadata( 5902 sqlite3 *db, /* Connection handle */ 5903 const char *zDbName, /* Database name or NULL */ 5904 const char *zTableName, /* Table name */ 5905 const char *zColumnName, /* Column name */ 5906 char const **pzDataType, /* OUTPUT: Declared data type */ 5907 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5908 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5909 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5910 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5911); 5912 5913/* 5914** CAPI3REF: Load An Extension 5915** METHOD: sqlite3 5916** 5917** ^This interface loads an SQLite extension library from the named file. 5918** 5919** ^The sqlite3_load_extension() interface attempts to load an 5920** [SQLite extension] library contained in the file zFile. If 5921** the file cannot be loaded directly, attempts are made to load 5922** with various operating-system specific extensions added. 5923** So for example, if "samplelib" cannot be loaded, then names like 5924** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5925** be tried also. 5926** 5927** ^The entry point is zProc. 5928** ^(zProc may be 0, in which case SQLite will try to come up with an 5929** entry point name on its own. It first tries "sqlite3_extension_init". 5930** If that does not work, it constructs a name "sqlite3_X_init" where the 5931** X is consists of the lower-case equivalent of all ASCII alphabetic 5932** characters in the filename from the last "/" to the first following 5933** "." and omitting any initial "lib".)^ 5934** ^The sqlite3_load_extension() interface returns 5935** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5936** ^If an error occurs and pzErrMsg is not 0, then the 5937** [sqlite3_load_extension()] interface shall attempt to 5938** fill *pzErrMsg with error message text stored in memory 5939** obtained from [sqlite3_malloc()]. The calling function 5940** should free this memory by calling [sqlite3_free()]. 5941** 5942** ^Extension loading must be enabled using 5943** [sqlite3_enable_load_extension()] or 5944** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5945** prior to calling this API, 5946** otherwise an error will be returned. 5947** 5948** <b>Security warning:</b> It is recommended that the 5949** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5950** interface. The use of the [sqlite3_enable_load_extension()] interface 5951** should be avoided. This will keep the SQL function [load_extension()] 5952** disabled and prevent SQL injections from giving attackers 5953** access to extension loading capabilities. 5954** 5955** See also the [load_extension() SQL function]. 5956*/ 5957int sqlite3_load_extension( 5958 sqlite3 *db, /* Load the extension into this database connection */ 5959 const char *zFile, /* Name of the shared library containing extension */ 5960 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5961 char **pzErrMsg /* Put error message here if not 0 */ 5962); 5963 5964/* 5965** CAPI3REF: Enable Or Disable Extension Loading 5966** METHOD: sqlite3 5967** 5968** ^So as not to open security holes in older applications that are 5969** unprepared to deal with [extension loading], and as a means of disabling 5970** [extension loading] while evaluating user-entered SQL, the following API 5971** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5972** 5973** ^Extension loading is off by default. 5974** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5975** to turn extension loading on and call it with onoff==0 to turn 5976** it back off again. 5977** 5978** ^This interface enables or disables both the C-API 5979** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5980** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5981** to enable or disable only the C-API.)^ 5982** 5983** <b>Security warning:</b> It is recommended that extension loading 5984** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5985** rather than this interface, so the [load_extension()] SQL function 5986** remains disabled. This will prevent SQL injections from giving attackers 5987** access to extension loading capabilities. 5988*/ 5989int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5990 5991/* 5992** CAPI3REF: Automatically Load Statically Linked Extensions 5993** 5994** ^This interface causes the xEntryPoint() function to be invoked for 5995** each new [database connection] that is created. The idea here is that 5996** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5997** that is to be automatically loaded into all new database connections. 5998** 5999** ^(Even though the function prototype shows that xEntryPoint() takes 6000** no arguments and returns void, SQLite invokes xEntryPoint() with three 6001** arguments and expects an integer result as if the signature of the 6002** entry point where as follows: 6003** 6004** <blockquote><pre> 6005** int xEntryPoint( 6006** sqlite3 *db, 6007** const char **pzErrMsg, 6008** const struct sqlite3_api_routines *pThunk 6009** ); 6010** </pre></blockquote>)^ 6011** 6012** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6013** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6014** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6015** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6016** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6017** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6018** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6019** 6020** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6021** on the list of automatic extensions is a harmless no-op. ^No entry point 6022** will be called more than once for each database connection that is opened. 6023** 6024** See also: [sqlite3_reset_auto_extension()] 6025** and [sqlite3_cancel_auto_extension()] 6026*/ 6027int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6028 6029/* 6030** CAPI3REF: Cancel Automatic Extension Loading 6031** 6032** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6033** initialization routine X that was registered using a prior call to 6034** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6035** routine returns 1 if initialization routine X was successfully 6036** unregistered and it returns 0 if X was not on the list of initialization 6037** routines. 6038*/ 6039int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6040 6041/* 6042** CAPI3REF: Reset Automatic Extension Loading 6043** 6044** ^This interface disables all automatic extensions previously 6045** registered using [sqlite3_auto_extension()]. 6046*/ 6047void sqlite3_reset_auto_extension(void); 6048 6049/* 6050** The interface to the virtual-table mechanism is currently considered 6051** to be experimental. The interface might change in incompatible ways. 6052** If this is a problem for you, do not use the interface at this time. 6053** 6054** When the virtual-table mechanism stabilizes, we will declare the 6055** interface fixed, support it indefinitely, and remove this comment. 6056*/ 6057 6058/* 6059** Structures used by the virtual table interface 6060*/ 6061typedef struct sqlite3_vtab sqlite3_vtab; 6062typedef struct sqlite3_index_info sqlite3_index_info; 6063typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6064typedef struct sqlite3_module sqlite3_module; 6065 6066/* 6067** CAPI3REF: Virtual Table Object 6068** KEYWORDS: sqlite3_module {virtual table module} 6069** 6070** This structure, sometimes called a "virtual table module", 6071** defines the implementation of a [virtual tables]. 6072** This structure consists mostly of methods for the module. 6073** 6074** ^A virtual table module is created by filling in a persistent 6075** instance of this structure and passing a pointer to that instance 6076** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6077** ^The registration remains valid until it is replaced by a different 6078** module or until the [database connection] closes. The content 6079** of this structure must not change while it is registered with 6080** any database connection. 6081*/ 6082struct sqlite3_module { 6083 int iVersion; 6084 int (*xCreate)(sqlite3*, void *pAux, 6085 int argc, const char *const*argv, 6086 sqlite3_vtab **ppVTab, char**); 6087 int (*xConnect)(sqlite3*, void *pAux, 6088 int argc, const char *const*argv, 6089 sqlite3_vtab **ppVTab, char**); 6090 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6091 int (*xDisconnect)(sqlite3_vtab *pVTab); 6092 int (*xDestroy)(sqlite3_vtab *pVTab); 6093 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6094 int (*xClose)(sqlite3_vtab_cursor*); 6095 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6096 int argc, sqlite3_value **argv); 6097 int (*xNext)(sqlite3_vtab_cursor*); 6098 int (*xEof)(sqlite3_vtab_cursor*); 6099 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6100 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6101 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6102 int (*xBegin)(sqlite3_vtab *pVTab); 6103 int (*xSync)(sqlite3_vtab *pVTab); 6104 int (*xCommit)(sqlite3_vtab *pVTab); 6105 int (*xRollback)(sqlite3_vtab *pVTab); 6106 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6107 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6108 void **ppArg); 6109 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6110 /* The methods above are in version 1 of the sqlite_module object. Those 6111 ** below are for version 2 and greater. */ 6112 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6113 int (*xRelease)(sqlite3_vtab *pVTab, int); 6114 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6115}; 6116 6117/* 6118** CAPI3REF: Virtual Table Indexing Information 6119** KEYWORDS: sqlite3_index_info 6120** 6121** The sqlite3_index_info structure and its substructures is used as part 6122** of the [virtual table] interface to 6123** pass information into and receive the reply from the [xBestIndex] 6124** method of a [virtual table module]. The fields under **Inputs** are the 6125** inputs to xBestIndex and are read-only. xBestIndex inserts its 6126** results into the **Outputs** fields. 6127** 6128** ^(The aConstraint[] array records WHERE clause constraints of the form: 6129** 6130** <blockquote>column OP expr</blockquote> 6131** 6132** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6133** stored in aConstraint[].op using one of the 6134** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6135** ^(The index of the column is stored in 6136** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6137** expr on the right-hand side can be evaluated (and thus the constraint 6138** is usable) and false if it cannot.)^ 6139** 6140** ^The optimizer automatically inverts terms of the form "expr OP column" 6141** and makes other simplifications to the WHERE clause in an attempt to 6142** get as many WHERE clause terms into the form shown above as possible. 6143** ^The aConstraint[] array only reports WHERE clause terms that are 6144** relevant to the particular virtual table being queried. 6145** 6146** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6147** ^Each term of aOrderBy records a column of the ORDER BY clause. 6148** 6149** The colUsed field indicates which columns of the virtual table may be 6150** required by the current scan. Virtual table columns are numbered from 6151** zero in the order in which they appear within the CREATE TABLE statement 6152** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6153** the corresponding bit is set within the colUsed mask if the column may be 6154** required by SQLite. If the table has at least 64 columns and any column 6155** to the right of the first 63 is required, then bit 63 of colUsed is also 6156** set. In other words, column iCol may be required if the expression 6157** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6158** non-zero. 6159** 6160** The [xBestIndex] method must fill aConstraintUsage[] with information 6161** about what parameters to pass to xFilter. ^If argvIndex>0 then 6162** the right-hand side of the corresponding aConstraint[] is evaluated 6163** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6164** is true, then the constraint is assumed to be fully handled by the 6165** virtual table and is not checked again by SQLite.)^ 6166** 6167** ^The idxNum and idxPtr values are recorded and passed into the 6168** [xFilter] method. 6169** ^[sqlite3_free()] is used to free idxPtr if and only if 6170** needToFreeIdxPtr is true. 6171** 6172** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6173** the correct order to satisfy the ORDER BY clause so that no separate 6174** sorting step is required. 6175** 6176** ^The estimatedCost value is an estimate of the cost of a particular 6177** strategy. A cost of N indicates that the cost of the strategy is similar 6178** to a linear scan of an SQLite table with N rows. A cost of log(N) 6179** indicates that the expense of the operation is similar to that of a 6180** binary search on a unique indexed field of an SQLite table with N rows. 6181** 6182** ^The estimatedRows value is an estimate of the number of rows that 6183** will be returned by the strategy. 6184** 6185** The xBestIndex method may optionally populate the idxFlags field with a 6186** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6187** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6188** assumes that the strategy may visit at most one row. 6189** 6190** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6191** SQLite also assumes that if a call to the xUpdate() method is made as 6192** part of the same statement to delete or update a virtual table row and the 6193** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6194** any database changes. In other words, if the xUpdate() returns 6195** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6196** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6197** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6198** the xUpdate method are automatically rolled back by SQLite. 6199** 6200** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6201** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6202** If a virtual table extension is 6203** used with an SQLite version earlier than 3.8.2, the results of attempting 6204** to read or write the estimatedRows field are undefined (but are likely 6205** to included crashing the application). The estimatedRows field should 6206** therefore only be used if [sqlite3_libversion_number()] returns a 6207** value greater than or equal to 3008002. Similarly, the idxFlags field 6208** was added for [version 3.9.0] ([dateof:3.9.0]). 6209** It may therefore only be used if 6210** sqlite3_libversion_number() returns a value greater than or equal to 6211** 3009000. 6212*/ 6213struct sqlite3_index_info { 6214 /* Inputs */ 6215 int nConstraint; /* Number of entries in aConstraint */ 6216 struct sqlite3_index_constraint { 6217 int iColumn; /* Column constrained. -1 for ROWID */ 6218 unsigned char op; /* Constraint operator */ 6219 unsigned char usable; /* True if this constraint is usable */ 6220 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6221 } *aConstraint; /* Table of WHERE clause constraints */ 6222 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6223 struct sqlite3_index_orderby { 6224 int iColumn; /* Column number */ 6225 unsigned char desc; /* True for DESC. False for ASC. */ 6226 } *aOrderBy; /* The ORDER BY clause */ 6227 /* Outputs */ 6228 struct sqlite3_index_constraint_usage { 6229 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6230 unsigned char omit; /* Do not code a test for this constraint */ 6231 } *aConstraintUsage; 6232 int idxNum; /* Number used to identify the index */ 6233 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6234 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6235 int orderByConsumed; /* True if output is already ordered */ 6236 double estimatedCost; /* Estimated cost of using this index */ 6237 /* Fields below are only available in SQLite 3.8.2 and later */ 6238 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6239 /* Fields below are only available in SQLite 3.9.0 and later */ 6240 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6241 /* Fields below are only available in SQLite 3.10.0 and later */ 6242 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6243}; 6244 6245/* 6246** CAPI3REF: Virtual Table Scan Flags 6247*/ 6248#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6249 6250/* 6251** CAPI3REF: Virtual Table Constraint Operator Codes 6252** 6253** These macros defined the allowed values for the 6254** [sqlite3_index_info].aConstraint[].op field. Each value represents 6255** an operator that is part of a constraint term in the wHERE clause of 6256** a query that uses a [virtual table]. 6257*/ 6258#define SQLITE_INDEX_CONSTRAINT_EQ 2 6259#define SQLITE_INDEX_CONSTRAINT_GT 4 6260#define SQLITE_INDEX_CONSTRAINT_LE 8 6261#define SQLITE_INDEX_CONSTRAINT_LT 16 6262#define SQLITE_INDEX_CONSTRAINT_GE 32 6263#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6264#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6265#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6266#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6267#define SQLITE_INDEX_CONSTRAINT_NE 68 6268#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6269#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6270#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6271#define SQLITE_INDEX_CONSTRAINT_IS 72 6272 6273/* 6274** CAPI3REF: Register A Virtual Table Implementation 6275** METHOD: sqlite3 6276** 6277** ^These routines are used to register a new [virtual table module] name. 6278** ^Module names must be registered before 6279** creating a new [virtual table] using the module and before using a 6280** preexisting [virtual table] for the module. 6281** 6282** ^The module name is registered on the [database connection] specified 6283** by the first parameter. ^The name of the module is given by the 6284** second parameter. ^The third parameter is a pointer to 6285** the implementation of the [virtual table module]. ^The fourth 6286** parameter is an arbitrary client data pointer that is passed through 6287** into the [xCreate] and [xConnect] methods of the virtual table module 6288** when a new virtual table is be being created or reinitialized. 6289** 6290** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6291** is a pointer to a destructor for the pClientData. ^SQLite will 6292** invoke the destructor function (if it is not NULL) when SQLite 6293** no longer needs the pClientData pointer. ^The destructor will also 6294** be invoked if the call to sqlite3_create_module_v2() fails. 6295** ^The sqlite3_create_module() 6296** interface is equivalent to sqlite3_create_module_v2() with a NULL 6297** destructor. 6298*/ 6299int sqlite3_create_module( 6300 sqlite3 *db, /* SQLite connection to register module with */ 6301 const char *zName, /* Name of the module */ 6302 const sqlite3_module *p, /* Methods for the module */ 6303 void *pClientData /* Client data for xCreate/xConnect */ 6304); 6305int sqlite3_create_module_v2( 6306 sqlite3 *db, /* SQLite connection to register module with */ 6307 const char *zName, /* Name of the module */ 6308 const sqlite3_module *p, /* Methods for the module */ 6309 void *pClientData, /* Client data for xCreate/xConnect */ 6310 void(*xDestroy)(void*) /* Module destructor function */ 6311); 6312 6313/* 6314** CAPI3REF: Virtual Table Instance Object 6315** KEYWORDS: sqlite3_vtab 6316** 6317** Every [virtual table module] implementation uses a subclass 6318** of this object to describe a particular instance 6319** of the [virtual table]. Each subclass will 6320** be tailored to the specific needs of the module implementation. 6321** The purpose of this superclass is to define certain fields that are 6322** common to all module implementations. 6323** 6324** ^Virtual tables methods can set an error message by assigning a 6325** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6326** take care that any prior string is freed by a call to [sqlite3_free()] 6327** prior to assigning a new string to zErrMsg. ^After the error message 6328** is delivered up to the client application, the string will be automatically 6329** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6330*/ 6331struct sqlite3_vtab { 6332 const sqlite3_module *pModule; /* The module for this virtual table */ 6333 int nRef; /* Number of open cursors */ 6334 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6335 /* Virtual table implementations will typically add additional fields */ 6336}; 6337 6338/* 6339** CAPI3REF: Virtual Table Cursor Object 6340** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6341** 6342** Every [virtual table module] implementation uses a subclass of the 6343** following structure to describe cursors that point into the 6344** [virtual table] and are used 6345** to loop through the virtual table. Cursors are created using the 6346** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6347** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6348** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6349** of the module. Each module implementation will define 6350** the content of a cursor structure to suit its own needs. 6351** 6352** This superclass exists in order to define fields of the cursor that 6353** are common to all implementations. 6354*/ 6355struct sqlite3_vtab_cursor { 6356 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6357 /* Virtual table implementations will typically add additional fields */ 6358}; 6359 6360/* 6361** CAPI3REF: Declare The Schema Of A Virtual Table 6362** 6363** ^The [xCreate] and [xConnect] methods of a 6364** [virtual table module] call this interface 6365** to declare the format (the names and datatypes of the columns) of 6366** the virtual tables they implement. 6367*/ 6368int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6369 6370/* 6371** CAPI3REF: Overload A Function For A Virtual Table 6372** METHOD: sqlite3 6373** 6374** ^(Virtual tables can provide alternative implementations of functions 6375** using the [xFindFunction] method of the [virtual table module]. 6376** But global versions of those functions 6377** must exist in order to be overloaded.)^ 6378** 6379** ^(This API makes sure a global version of a function with a particular 6380** name and number of parameters exists. If no such function exists 6381** before this API is called, a new function is created.)^ ^The implementation 6382** of the new function always causes an exception to be thrown. So 6383** the new function is not good for anything by itself. Its only 6384** purpose is to be a placeholder function that can be overloaded 6385** by a [virtual table]. 6386*/ 6387int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6388 6389/* 6390** The interface to the virtual-table mechanism defined above (back up 6391** to a comment remarkably similar to this one) is currently considered 6392** to be experimental. The interface might change in incompatible ways. 6393** If this is a problem for you, do not use the interface at this time. 6394** 6395** When the virtual-table mechanism stabilizes, we will declare the 6396** interface fixed, support it indefinitely, and remove this comment. 6397*/ 6398 6399/* 6400** CAPI3REF: A Handle To An Open BLOB 6401** KEYWORDS: {BLOB handle} {BLOB handles} 6402** 6403** An instance of this object represents an open BLOB on which 6404** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6405** ^Objects of this type are created by [sqlite3_blob_open()] 6406** and destroyed by [sqlite3_blob_close()]. 6407** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6408** can be used to read or write small subsections of the BLOB. 6409** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6410*/ 6411typedef struct sqlite3_blob sqlite3_blob; 6412 6413/* 6414** CAPI3REF: Open A BLOB For Incremental I/O 6415** METHOD: sqlite3 6416** CONSTRUCTOR: sqlite3_blob 6417** 6418** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6419** in row iRow, column zColumn, table zTable in database zDb; 6420** in other words, the same BLOB that would be selected by: 6421** 6422** <pre> 6423** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6424** </pre>)^ 6425** 6426** ^(Parameter zDb is not the filename that contains the database, but 6427** rather the symbolic name of the database. For attached databases, this is 6428** the name that appears after the AS keyword in the [ATTACH] statement. 6429** For the main database file, the database name is "main". For TEMP 6430** tables, the database name is "temp".)^ 6431** 6432** ^If the flags parameter is non-zero, then the BLOB is opened for read 6433** and write access. ^If the flags parameter is zero, the BLOB is opened for 6434** read-only access. 6435** 6436** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6437** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6438** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6439** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6440** on *ppBlob after this function it returns. 6441** 6442** This function fails with SQLITE_ERROR if any of the following are true: 6443** <ul> 6444** <li> ^(Database zDb does not exist)^, 6445** <li> ^(Table zTable does not exist within database zDb)^, 6446** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6447** <li> ^(Column zColumn does not exist)^, 6448** <li> ^(Row iRow is not present in the table)^, 6449** <li> ^(The specified column of row iRow contains a value that is not 6450** a TEXT or BLOB value)^, 6451** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6452** constraint and the blob is being opened for read/write access)^, 6453** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6454** column zColumn is part of a [child key] definition and the blob is 6455** being opened for read/write access)^. 6456** </ul> 6457** 6458** ^Unless it returns SQLITE_MISUSE, this function sets the 6459** [database connection] error code and message accessible via 6460** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6461** 6462** A BLOB referenced by sqlite3_blob_open() may be read using the 6463** [sqlite3_blob_read()] interface and modified by using 6464** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6465** different row of the same table using the [sqlite3_blob_reopen()] 6466** interface. However, the column, table, or database of a [BLOB handle] 6467** cannot be changed after the [BLOB handle] is opened. 6468** 6469** ^(If the row that a BLOB handle points to is modified by an 6470** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6471** then the BLOB handle is marked as "expired". 6472** This is true if any column of the row is changed, even a column 6473** other than the one the BLOB handle is open on.)^ 6474** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6475** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6476** ^(Changes written into a BLOB prior to the BLOB expiring are not 6477** rolled back by the expiration of the BLOB. Such changes will eventually 6478** commit if the transaction continues to completion.)^ 6479** 6480** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6481** the opened blob. ^The size of a blob may not be changed by this 6482** interface. Use the [UPDATE] SQL command to change the size of a 6483** blob. 6484** 6485** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6486** and the built-in [zeroblob] SQL function may be used to create a 6487** zero-filled blob to read or write using the incremental-blob interface. 6488** 6489** To avoid a resource leak, every open [BLOB handle] should eventually 6490** be released by a call to [sqlite3_blob_close()]. 6491** 6492** See also: [sqlite3_blob_close()], 6493** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6494** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6495*/ 6496int sqlite3_blob_open( 6497 sqlite3*, 6498 const char *zDb, 6499 const char *zTable, 6500 const char *zColumn, 6501 sqlite3_int64 iRow, 6502 int flags, 6503 sqlite3_blob **ppBlob 6504); 6505 6506/* 6507** CAPI3REF: Move a BLOB Handle to a New Row 6508** METHOD: sqlite3_blob 6509** 6510** ^This function is used to move an existing [BLOB handle] so that it points 6511** to a different row of the same database table. ^The new row is identified 6512** by the rowid value passed as the second argument. Only the row can be 6513** changed. ^The database, table and column on which the blob handle is open 6514** remain the same. Moving an existing [BLOB handle] to a new row is 6515** faster than closing the existing handle and opening a new one. 6516** 6517** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6518** it must exist and there must be either a blob or text value stored in 6519** the nominated column.)^ ^If the new row is not present in the table, or if 6520** it does not contain a blob or text value, or if another error occurs, an 6521** SQLite error code is returned and the blob handle is considered aborted. 6522** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6523** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6524** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6525** always returns zero. 6526** 6527** ^This function sets the database handle error code and message. 6528*/ 6529int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6530 6531/* 6532** CAPI3REF: Close A BLOB Handle 6533** DESTRUCTOR: sqlite3_blob 6534** 6535** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6536** unconditionally. Even if this routine returns an error code, the 6537** handle is still closed.)^ 6538** 6539** ^If the blob handle being closed was opened for read-write access, and if 6540** the database is in auto-commit mode and there are no other open read-write 6541** blob handles or active write statements, the current transaction is 6542** committed. ^If an error occurs while committing the transaction, an error 6543** code is returned and the transaction rolled back. 6544** 6545** Calling this function with an argument that is not a NULL pointer or an 6546** open blob handle results in undefined behaviour. ^Calling this routine 6547** with a null pointer (such as would be returned by a failed call to 6548** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6549** is passed a valid open blob handle, the values returned by the 6550** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6551*/ 6552int sqlite3_blob_close(sqlite3_blob *); 6553 6554/* 6555** CAPI3REF: Return The Size Of An Open BLOB 6556** METHOD: sqlite3_blob 6557** 6558** ^Returns the size in bytes of the BLOB accessible via the 6559** successfully opened [BLOB handle] in its only argument. ^The 6560** incremental blob I/O routines can only read or overwriting existing 6561** blob content; they cannot change the size of a blob. 6562** 6563** This routine only works on a [BLOB handle] which has been created 6564** by a prior successful call to [sqlite3_blob_open()] and which has not 6565** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6566** to this routine results in undefined and probably undesirable behavior. 6567*/ 6568int sqlite3_blob_bytes(sqlite3_blob *); 6569 6570/* 6571** CAPI3REF: Read Data From A BLOB Incrementally 6572** METHOD: sqlite3_blob 6573** 6574** ^(This function is used to read data from an open [BLOB handle] into a 6575** caller-supplied buffer. N bytes of data are copied into buffer Z 6576** from the open BLOB, starting at offset iOffset.)^ 6577** 6578** ^If offset iOffset is less than N bytes from the end of the BLOB, 6579** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6580** less than zero, [SQLITE_ERROR] is returned and no data is read. 6581** ^The size of the blob (and hence the maximum value of N+iOffset) 6582** can be determined using the [sqlite3_blob_bytes()] interface. 6583** 6584** ^An attempt to read from an expired [BLOB handle] fails with an 6585** error code of [SQLITE_ABORT]. 6586** 6587** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6588** Otherwise, an [error code] or an [extended error code] is returned.)^ 6589** 6590** This routine only works on a [BLOB handle] which has been created 6591** by a prior successful call to [sqlite3_blob_open()] and which has not 6592** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6593** to this routine results in undefined and probably undesirable behavior. 6594** 6595** See also: [sqlite3_blob_write()]. 6596*/ 6597int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6598 6599/* 6600** CAPI3REF: Write Data Into A BLOB Incrementally 6601** METHOD: sqlite3_blob 6602** 6603** ^(This function is used to write data into an open [BLOB handle] from a 6604** caller-supplied buffer. N bytes of data are copied from the buffer Z 6605** into the open BLOB, starting at offset iOffset.)^ 6606** 6607** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6608** Otherwise, an [error code] or an [extended error code] is returned.)^ 6609** ^Unless SQLITE_MISUSE is returned, this function sets the 6610** [database connection] error code and message accessible via 6611** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6612** 6613** ^If the [BLOB handle] passed as the first argument was not opened for 6614** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6615** this function returns [SQLITE_READONLY]. 6616** 6617** This function may only modify the contents of the BLOB; it is 6618** not possible to increase the size of a BLOB using this API. 6619** ^If offset iOffset is less than N bytes from the end of the BLOB, 6620** [SQLITE_ERROR] is returned and no data is written. The size of the 6621** BLOB (and hence the maximum value of N+iOffset) can be determined 6622** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6623** than zero [SQLITE_ERROR] is returned and no data is written. 6624** 6625** ^An attempt to write to an expired [BLOB handle] fails with an 6626** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6627** before the [BLOB handle] expired are not rolled back by the 6628** expiration of the handle, though of course those changes might 6629** have been overwritten by the statement that expired the BLOB handle 6630** or by other independent statements. 6631** 6632** This routine only works on a [BLOB handle] which has been created 6633** by a prior successful call to [sqlite3_blob_open()] and which has not 6634** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6635** to this routine results in undefined and probably undesirable behavior. 6636** 6637** See also: [sqlite3_blob_read()]. 6638*/ 6639int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6640 6641/* 6642** CAPI3REF: Virtual File System Objects 6643** 6644** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6645** that SQLite uses to interact 6646** with the underlying operating system. Most SQLite builds come with a 6647** single default VFS that is appropriate for the host computer. 6648** New VFSes can be registered and existing VFSes can be unregistered. 6649** The following interfaces are provided. 6650** 6651** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6652** ^Names are case sensitive. 6653** ^Names are zero-terminated UTF-8 strings. 6654** ^If there is no match, a NULL pointer is returned. 6655** ^If zVfsName is NULL then the default VFS is returned. 6656** 6657** ^New VFSes are registered with sqlite3_vfs_register(). 6658** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6659** ^The same VFS can be registered multiple times without injury. 6660** ^To make an existing VFS into the default VFS, register it again 6661** with the makeDflt flag set. If two different VFSes with the 6662** same name are registered, the behavior is undefined. If a 6663** VFS is registered with a name that is NULL or an empty string, 6664** then the behavior is undefined. 6665** 6666** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6667** ^(If the default VFS is unregistered, another VFS is chosen as 6668** the default. The choice for the new VFS is arbitrary.)^ 6669*/ 6670sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6671int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6672int sqlite3_vfs_unregister(sqlite3_vfs*); 6673 6674/* 6675** CAPI3REF: Mutexes 6676** 6677** The SQLite core uses these routines for thread 6678** synchronization. Though they are intended for internal 6679** use by SQLite, code that links against SQLite is 6680** permitted to use any of these routines. 6681** 6682** The SQLite source code contains multiple implementations 6683** of these mutex routines. An appropriate implementation 6684** is selected automatically at compile-time. The following 6685** implementations are available in the SQLite core: 6686** 6687** <ul> 6688** <li> SQLITE_MUTEX_PTHREADS 6689** <li> SQLITE_MUTEX_W32 6690** <li> SQLITE_MUTEX_NOOP 6691** </ul> 6692** 6693** The SQLITE_MUTEX_NOOP implementation is a set of routines 6694** that does no real locking and is appropriate for use in 6695** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6696** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6697** and Windows. 6698** 6699** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6700** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6701** implementation is included with the library. In this case the 6702** application must supply a custom mutex implementation using the 6703** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6704** before calling sqlite3_initialize() or any other public sqlite3_ 6705** function that calls sqlite3_initialize(). 6706** 6707** ^The sqlite3_mutex_alloc() routine allocates a new 6708** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6709** routine returns NULL if it is unable to allocate the requested 6710** mutex. The argument to sqlite3_mutex_alloc() must one of these 6711** integer constants: 6712** 6713** <ul> 6714** <li> SQLITE_MUTEX_FAST 6715** <li> SQLITE_MUTEX_RECURSIVE 6716** <li> SQLITE_MUTEX_STATIC_MASTER 6717** <li> SQLITE_MUTEX_STATIC_MEM 6718** <li> SQLITE_MUTEX_STATIC_OPEN 6719** <li> SQLITE_MUTEX_STATIC_PRNG 6720** <li> SQLITE_MUTEX_STATIC_LRU 6721** <li> SQLITE_MUTEX_STATIC_PMEM 6722** <li> SQLITE_MUTEX_STATIC_APP1 6723** <li> SQLITE_MUTEX_STATIC_APP2 6724** <li> SQLITE_MUTEX_STATIC_APP3 6725** <li> SQLITE_MUTEX_STATIC_VFS1 6726** <li> SQLITE_MUTEX_STATIC_VFS2 6727** <li> SQLITE_MUTEX_STATIC_VFS3 6728** </ul> 6729** 6730** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6731** cause sqlite3_mutex_alloc() to create 6732** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6733** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6734** The mutex implementation does not need to make a distinction 6735** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6736** not want to. SQLite will only request a recursive mutex in 6737** cases where it really needs one. If a faster non-recursive mutex 6738** implementation is available on the host platform, the mutex subsystem 6739** might return such a mutex in response to SQLITE_MUTEX_FAST. 6740** 6741** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6742** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6743** a pointer to a static preexisting mutex. ^Nine static mutexes are 6744** used by the current version of SQLite. Future versions of SQLite 6745** may add additional static mutexes. Static mutexes are for internal 6746** use by SQLite only. Applications that use SQLite mutexes should 6747** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6748** SQLITE_MUTEX_RECURSIVE. 6749** 6750** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6751** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6752** returns a different mutex on every call. ^For the static 6753** mutex types, the same mutex is returned on every call that has 6754** the same type number. 6755** 6756** ^The sqlite3_mutex_free() routine deallocates a previously 6757** allocated dynamic mutex. Attempting to deallocate a static 6758** mutex results in undefined behavior. 6759** 6760** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6761** to enter a mutex. ^If another thread is already within the mutex, 6762** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6763** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6764** upon successful entry. ^(Mutexes created using 6765** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6766** In such cases, the 6767** mutex must be exited an equal number of times before another thread 6768** can enter.)^ If the same thread tries to enter any mutex other 6769** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6770** 6771** ^(Some systems (for example, Windows 95) do not support the operation 6772** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6773** will always return SQLITE_BUSY. The SQLite core only ever uses 6774** sqlite3_mutex_try() as an optimization so this is acceptable 6775** behavior.)^ 6776** 6777** ^The sqlite3_mutex_leave() routine exits a mutex that was 6778** previously entered by the same thread. The behavior 6779** is undefined if the mutex is not currently entered by the 6780** calling thread or is not currently allocated. 6781** 6782** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6783** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6784** behave as no-ops. 6785** 6786** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6787*/ 6788sqlite3_mutex *sqlite3_mutex_alloc(int); 6789void sqlite3_mutex_free(sqlite3_mutex*); 6790void sqlite3_mutex_enter(sqlite3_mutex*); 6791int sqlite3_mutex_try(sqlite3_mutex*); 6792void sqlite3_mutex_leave(sqlite3_mutex*); 6793 6794/* 6795** CAPI3REF: Mutex Methods Object 6796** 6797** An instance of this structure defines the low-level routines 6798** used to allocate and use mutexes. 6799** 6800** Usually, the default mutex implementations provided by SQLite are 6801** sufficient, however the application has the option of substituting a custom 6802** implementation for specialized deployments or systems for which SQLite 6803** does not provide a suitable implementation. In this case, the application 6804** creates and populates an instance of this structure to pass 6805** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6806** Additionally, an instance of this structure can be used as an 6807** output variable when querying the system for the current mutex 6808** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6809** 6810** ^The xMutexInit method defined by this structure is invoked as 6811** part of system initialization by the sqlite3_initialize() function. 6812** ^The xMutexInit routine is called by SQLite exactly once for each 6813** effective call to [sqlite3_initialize()]. 6814** 6815** ^The xMutexEnd method defined by this structure is invoked as 6816** part of system shutdown by the sqlite3_shutdown() function. The 6817** implementation of this method is expected to release all outstanding 6818** resources obtained by the mutex methods implementation, especially 6819** those obtained by the xMutexInit method. ^The xMutexEnd() 6820** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6821** 6822** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6823** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6824** xMutexNotheld) implement the following interfaces (respectively): 6825** 6826** <ul> 6827** <li> [sqlite3_mutex_alloc()] </li> 6828** <li> [sqlite3_mutex_free()] </li> 6829** <li> [sqlite3_mutex_enter()] </li> 6830** <li> [sqlite3_mutex_try()] </li> 6831** <li> [sqlite3_mutex_leave()] </li> 6832** <li> [sqlite3_mutex_held()] </li> 6833** <li> [sqlite3_mutex_notheld()] </li> 6834** </ul>)^ 6835** 6836** The only difference is that the public sqlite3_XXX functions enumerated 6837** above silently ignore any invocations that pass a NULL pointer instead 6838** of a valid mutex handle. The implementations of the methods defined 6839** by this structure are not required to handle this case, the results 6840** of passing a NULL pointer instead of a valid mutex handle are undefined 6841** (i.e. it is acceptable to provide an implementation that segfaults if 6842** it is passed a NULL pointer). 6843** 6844** The xMutexInit() method must be threadsafe. It must be harmless to 6845** invoke xMutexInit() multiple times within the same process and without 6846** intervening calls to xMutexEnd(). Second and subsequent calls to 6847** xMutexInit() must be no-ops. 6848** 6849** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6850** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6851** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6852** memory allocation for a fast or recursive mutex. 6853** 6854** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6855** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6856** If xMutexInit fails in any way, it is expected to clean up after itself 6857** prior to returning. 6858*/ 6859typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6860struct sqlite3_mutex_methods { 6861 int (*xMutexInit)(void); 6862 int (*xMutexEnd)(void); 6863 sqlite3_mutex *(*xMutexAlloc)(int); 6864 void (*xMutexFree)(sqlite3_mutex *); 6865 void (*xMutexEnter)(sqlite3_mutex *); 6866 int (*xMutexTry)(sqlite3_mutex *); 6867 void (*xMutexLeave)(sqlite3_mutex *); 6868 int (*xMutexHeld)(sqlite3_mutex *); 6869 int (*xMutexNotheld)(sqlite3_mutex *); 6870}; 6871 6872/* 6873** CAPI3REF: Mutex Verification Routines 6874** 6875** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6876** are intended for use inside assert() statements. The SQLite core 6877** never uses these routines except inside an assert() and applications 6878** are advised to follow the lead of the core. The SQLite core only 6879** provides implementations for these routines when it is compiled 6880** with the SQLITE_DEBUG flag. External mutex implementations 6881** are only required to provide these routines if SQLITE_DEBUG is 6882** defined and if NDEBUG is not defined. 6883** 6884** These routines should return true if the mutex in their argument 6885** is held or not held, respectively, by the calling thread. 6886** 6887** The implementation is not required to provide versions of these 6888** routines that actually work. If the implementation does not provide working 6889** versions of these routines, it should at least provide stubs that always 6890** return true so that one does not get spurious assertion failures. 6891** 6892** If the argument to sqlite3_mutex_held() is a NULL pointer then 6893** the routine should return 1. This seems counter-intuitive since 6894** clearly the mutex cannot be held if it does not exist. But 6895** the reason the mutex does not exist is because the build is not 6896** using mutexes. And we do not want the assert() containing the 6897** call to sqlite3_mutex_held() to fail, so a non-zero return is 6898** the appropriate thing to do. The sqlite3_mutex_notheld() 6899** interface should also return 1 when given a NULL pointer. 6900*/ 6901#ifndef NDEBUG 6902int sqlite3_mutex_held(sqlite3_mutex*); 6903int sqlite3_mutex_notheld(sqlite3_mutex*); 6904#endif 6905 6906/* 6907** CAPI3REF: Mutex Types 6908** 6909** The [sqlite3_mutex_alloc()] interface takes a single argument 6910** which is one of these integer constants. 6911** 6912** The set of static mutexes may change from one SQLite release to the 6913** next. Applications that override the built-in mutex logic must be 6914** prepared to accommodate additional static mutexes. 6915*/ 6916#define SQLITE_MUTEX_FAST 0 6917#define SQLITE_MUTEX_RECURSIVE 1 6918#define SQLITE_MUTEX_STATIC_MASTER 2 6919#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6920#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6921#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6922#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6923#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6924#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6925#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6926#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6927#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6928#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6929#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6930#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6931#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6932 6933/* 6934** CAPI3REF: Retrieve the mutex for a database connection 6935** METHOD: sqlite3 6936** 6937** ^This interface returns a pointer the [sqlite3_mutex] object that 6938** serializes access to the [database connection] given in the argument 6939** when the [threading mode] is Serialized. 6940** ^If the [threading mode] is Single-thread or Multi-thread then this 6941** routine returns a NULL pointer. 6942*/ 6943sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6944 6945/* 6946** CAPI3REF: Low-Level Control Of Database Files 6947** METHOD: sqlite3 6948** 6949** ^The [sqlite3_file_control()] interface makes a direct call to the 6950** xFileControl method for the [sqlite3_io_methods] object associated 6951** with a particular database identified by the second argument. ^The 6952** name of the database is "main" for the main database or "temp" for the 6953** TEMP database, or the name that appears after the AS keyword for 6954** databases that are added using the [ATTACH] SQL command. 6955** ^A NULL pointer can be used in place of "main" to refer to the 6956** main database file. 6957** ^The third and fourth parameters to this routine 6958** are passed directly through to the second and third parameters of 6959** the xFileControl method. ^The return value of the xFileControl 6960** method becomes the return value of this routine. 6961** 6962** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6963** a pointer to the underlying [sqlite3_file] object to be written into 6964** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6965** case is a short-circuit path which does not actually invoke the 6966** underlying sqlite3_io_methods.xFileControl method. 6967** 6968** ^If the second parameter (zDbName) does not match the name of any 6969** open database file, then SQLITE_ERROR is returned. ^This error 6970** code is not remembered and will not be recalled by [sqlite3_errcode()] 6971** or [sqlite3_errmsg()]. The underlying xFileControl method might 6972** also return SQLITE_ERROR. There is no way to distinguish between 6973** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6974** xFileControl method. 6975** 6976** See also: [SQLITE_FCNTL_LOCKSTATE] 6977*/ 6978int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6979 6980/* 6981** CAPI3REF: Testing Interface 6982** 6983** ^The sqlite3_test_control() interface is used to read out internal 6984** state of SQLite and to inject faults into SQLite for testing 6985** purposes. ^The first parameter is an operation code that determines 6986** the number, meaning, and operation of all subsequent parameters. 6987** 6988** This interface is not for use by applications. It exists solely 6989** for verifying the correct operation of the SQLite library. Depending 6990** on how the SQLite library is compiled, this interface might not exist. 6991** 6992** The details of the operation codes, their meanings, the parameters 6993** they take, and what they do are all subject to change without notice. 6994** Unlike most of the SQLite API, this function is not guaranteed to 6995** operate consistently from one release to the next. 6996*/ 6997int sqlite3_test_control(int op, ...); 6998 6999/* 7000** CAPI3REF: Testing Interface Operation Codes 7001** 7002** These constants are the valid operation code parameters used 7003** as the first argument to [sqlite3_test_control()]. 7004** 7005** These parameters and their meanings are subject to change 7006** without notice. These values are for testing purposes only. 7007** Applications should not use any of these parameters or the 7008** [sqlite3_test_control()] interface. 7009*/ 7010#define SQLITE_TESTCTRL_FIRST 5 7011#define SQLITE_TESTCTRL_PRNG_SAVE 5 7012#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7013#define SQLITE_TESTCTRL_PRNG_RESET 7 7014#define SQLITE_TESTCTRL_BITVEC_TEST 8 7015#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7016#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7017#define SQLITE_TESTCTRL_PENDING_BYTE 11 7018#define SQLITE_TESTCTRL_ASSERT 12 7019#define SQLITE_TESTCTRL_ALWAYS 13 7020#define SQLITE_TESTCTRL_RESERVE 14 7021#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7022#define SQLITE_TESTCTRL_ISKEYWORD 16 7023#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7024#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7025#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7026#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7027#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7028#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7029#define SQLITE_TESTCTRL_BYTEORDER 22 7030#define SQLITE_TESTCTRL_ISINIT 23 7031#define SQLITE_TESTCTRL_SORTER_MMAP 24 7032#define SQLITE_TESTCTRL_IMPOSTER 25 7033#define SQLITE_TESTCTRL_LAST 25 7034 7035/* 7036** CAPI3REF: SQLite Runtime Status 7037** 7038** ^These interfaces are used to retrieve runtime status information 7039** about the performance of SQLite, and optionally to reset various 7040** highwater marks. ^The first argument is an integer code for 7041** the specific parameter to measure. ^(Recognized integer codes 7042** are of the form [status parameters | SQLITE_STATUS_...].)^ 7043** ^The current value of the parameter is returned into *pCurrent. 7044** ^The highest recorded value is returned in *pHighwater. ^If the 7045** resetFlag is true, then the highest record value is reset after 7046** *pHighwater is written. ^(Some parameters do not record the highest 7047** value. For those parameters 7048** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7049** ^(Other parameters record only the highwater mark and not the current 7050** value. For these latter parameters nothing is written into *pCurrent.)^ 7051** 7052** ^The sqlite3_status() and sqlite3_status64() routines return 7053** SQLITE_OK on success and a non-zero [error code] on failure. 7054** 7055** If either the current value or the highwater mark is too large to 7056** be represented by a 32-bit integer, then the values returned by 7057** sqlite3_status() are undefined. 7058** 7059** See also: [sqlite3_db_status()] 7060*/ 7061int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7062int sqlite3_status64( 7063 int op, 7064 sqlite3_int64 *pCurrent, 7065 sqlite3_int64 *pHighwater, 7066 int resetFlag 7067); 7068 7069 7070/* 7071** CAPI3REF: Status Parameters 7072** KEYWORDS: {status parameters} 7073** 7074** These integer constants designate various run-time status parameters 7075** that can be returned by [sqlite3_status()]. 7076** 7077** <dl> 7078** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7079** <dd>This parameter is the current amount of memory checked out 7080** using [sqlite3_malloc()], either directly or indirectly. The 7081** figure includes calls made to [sqlite3_malloc()] by the application 7082** and internal memory usage by the SQLite library. Auxiliary page-cache 7083** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7084** this parameter. The amount returned is the sum of the allocation 7085** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7086** 7087** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7088** <dd>This parameter records the largest memory allocation request 7089** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7090** internal equivalents). Only the value returned in the 7091** *pHighwater parameter to [sqlite3_status()] is of interest. 7092** The value written into the *pCurrent parameter is undefined.</dd>)^ 7093** 7094** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7095** <dd>This parameter records the number of separate memory allocations 7096** currently checked out.</dd>)^ 7097** 7098** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7099** <dd>This parameter returns the number of pages used out of the 7100** [pagecache memory allocator] that was configured using 7101** [SQLITE_CONFIG_PAGECACHE]. The 7102** value returned is in pages, not in bytes.</dd>)^ 7103** 7104** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7105** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7106** <dd>This parameter returns the number of bytes of page cache 7107** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7108** buffer and where forced to overflow to [sqlite3_malloc()]. The 7109** returned value includes allocations that overflowed because they 7110** where too large (they were larger than the "sz" parameter to 7111** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7112** no space was left in the page cache.</dd>)^ 7113** 7114** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7115** <dd>This parameter records the largest memory allocation request 7116** handed to [pagecache memory allocator]. Only the value returned in the 7117** *pHighwater parameter to [sqlite3_status()] is of interest. 7118** The value written into the *pCurrent parameter is undefined.</dd>)^ 7119** 7120** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7121** <dd>No longer used.</dd> 7122** 7123** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7124** <dd>No longer used.</dd> 7125** 7126** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7127** <dd>No longer used.</dd> 7128** 7129** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7130** <dd>The *pHighwater parameter records the deepest parser stack. 7131** The *pCurrent value is undefined. The *pHighwater value is only 7132** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7133** </dl> 7134** 7135** New status parameters may be added from time to time. 7136*/ 7137#define SQLITE_STATUS_MEMORY_USED 0 7138#define SQLITE_STATUS_PAGECACHE_USED 1 7139#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7140#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7141#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7142#define SQLITE_STATUS_MALLOC_SIZE 5 7143#define SQLITE_STATUS_PARSER_STACK 6 7144#define SQLITE_STATUS_PAGECACHE_SIZE 7 7145#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7146#define SQLITE_STATUS_MALLOC_COUNT 9 7147 7148/* 7149** CAPI3REF: Database Connection Status 7150** METHOD: sqlite3 7151** 7152** ^This interface is used to retrieve runtime status information 7153** about a single [database connection]. ^The first argument is the 7154** database connection object to be interrogated. ^The second argument 7155** is an integer constant, taken from the set of 7156** [SQLITE_DBSTATUS options], that 7157** determines the parameter to interrogate. The set of 7158** [SQLITE_DBSTATUS options] is likely 7159** to grow in future releases of SQLite. 7160** 7161** ^The current value of the requested parameter is written into *pCur 7162** and the highest instantaneous value is written into *pHiwtr. ^If 7163** the resetFlg is true, then the highest instantaneous value is 7164** reset back down to the current value. 7165** 7166** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7167** non-zero [error code] on failure. 7168** 7169** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7170*/ 7171int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7172 7173/* 7174** CAPI3REF: Status Parameters for database connections 7175** KEYWORDS: {SQLITE_DBSTATUS options} 7176** 7177** These constants are the available integer "verbs" that can be passed as 7178** the second argument to the [sqlite3_db_status()] interface. 7179** 7180** New verbs may be added in future releases of SQLite. Existing verbs 7181** might be discontinued. Applications should check the return code from 7182** [sqlite3_db_status()] to make sure that the call worked. 7183** The [sqlite3_db_status()] interface will return a non-zero error code 7184** if a discontinued or unsupported verb is invoked. 7185** 7186** <dl> 7187** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7188** <dd>This parameter returns the number of lookaside memory slots currently 7189** checked out.</dd>)^ 7190** 7191** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7192** <dd>This parameter returns the number malloc attempts that were 7193** satisfied using lookaside memory. Only the high-water value is meaningful; 7194** the current value is always zero.)^ 7195** 7196** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7197** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7198** <dd>This parameter returns the number malloc attempts that might have 7199** been satisfied using lookaside memory but failed due to the amount of 7200** memory requested being larger than the lookaside slot size. 7201** Only the high-water value is meaningful; 7202** the current value is always zero.)^ 7203** 7204** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7205** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7206** <dd>This parameter returns the number malloc attempts that might have 7207** been satisfied using lookaside memory but failed due to all lookaside 7208** memory already being in use. 7209** Only the high-water value is meaningful; 7210** the current value is always zero.)^ 7211** 7212** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7213** <dd>This parameter returns the approximate number of bytes of heap 7214** memory used by all pager caches associated with the database connection.)^ 7215** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7216** 7217** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7218** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7219** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7220** pager cache is shared between two or more connections the bytes of heap 7221** memory used by that pager cache is divided evenly between the attached 7222** connections.)^ In other words, if none of the pager caches associated 7223** with the database connection are shared, this request returns the same 7224** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7225** shared, the value returned by this call will be smaller than that returned 7226** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7227** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7228** 7229** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7230** <dd>This parameter returns the approximate number of bytes of heap 7231** memory used to store the schema for all databases associated 7232** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7233** ^The full amount of memory used by the schemas is reported, even if the 7234** schema memory is shared with other database connections due to 7235** [shared cache mode] being enabled. 7236** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7237** 7238** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7239** <dd>This parameter returns the approximate number of bytes of heap 7240** and lookaside memory used by all prepared statements associated with 7241** the database connection.)^ 7242** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7243** </dd> 7244** 7245** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7246** <dd>This parameter returns the number of pager cache hits that have 7247** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7248** is always 0. 7249** </dd> 7250** 7251** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7252** <dd>This parameter returns the number of pager cache misses that have 7253** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7254** is always 0. 7255** </dd> 7256** 7257** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7258** <dd>This parameter returns the number of dirty cache entries that have 7259** been written to disk. Specifically, the number of pages written to the 7260** wal file in wal mode databases, or the number of pages written to the 7261** database file in rollback mode databases. Any pages written as part of 7262** transaction rollback or database recovery operations are not included. 7263** If an IO or other error occurs while writing a page to disk, the effect 7264** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7265** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7266** </dd> 7267** 7268** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7269** <dd>This parameter returns zero for the current value if and only if 7270** all foreign key constraints (deferred or immediate) have been 7271** resolved.)^ ^The highwater mark is always 0. 7272** </dd> 7273** </dl> 7274*/ 7275#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7276#define SQLITE_DBSTATUS_CACHE_USED 1 7277#define SQLITE_DBSTATUS_SCHEMA_USED 2 7278#define SQLITE_DBSTATUS_STMT_USED 3 7279#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7280#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7281#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7282#define SQLITE_DBSTATUS_CACHE_HIT 7 7283#define SQLITE_DBSTATUS_CACHE_MISS 8 7284#define SQLITE_DBSTATUS_CACHE_WRITE 9 7285#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7286#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7287#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7288 7289 7290/* 7291** CAPI3REF: Prepared Statement Status 7292** METHOD: sqlite3_stmt 7293** 7294** ^(Each prepared statement maintains various 7295** [SQLITE_STMTSTATUS counters] that measure the number 7296** of times it has performed specific operations.)^ These counters can 7297** be used to monitor the performance characteristics of the prepared 7298** statements. For example, if the number of table steps greatly exceeds 7299** the number of table searches or result rows, that would tend to indicate 7300** that the prepared statement is using a full table scan rather than 7301** an index. 7302** 7303** ^(This interface is used to retrieve and reset counter values from 7304** a [prepared statement]. The first argument is the prepared statement 7305** object to be interrogated. The second argument 7306** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7307** to be interrogated.)^ 7308** ^The current value of the requested counter is returned. 7309** ^If the resetFlg is true, then the counter is reset to zero after this 7310** interface call returns. 7311** 7312** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7313*/ 7314int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7315 7316/* 7317** CAPI3REF: Status Parameters for prepared statements 7318** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7319** 7320** These preprocessor macros define integer codes that name counter 7321** values associated with the [sqlite3_stmt_status()] interface. 7322** The meanings of the various counters are as follows: 7323** 7324** <dl> 7325** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7326** <dd>^This is the number of times that SQLite has stepped forward in 7327** a table as part of a full table scan. Large numbers for this counter 7328** may indicate opportunities for performance improvement through 7329** careful use of indices.</dd> 7330** 7331** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7332** <dd>^This is the number of sort operations that have occurred. 7333** A non-zero value in this counter may indicate an opportunity to 7334** improvement performance through careful use of indices.</dd> 7335** 7336** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7337** <dd>^This is the number of rows inserted into transient indices that 7338** were created automatically in order to help joins run faster. 7339** A non-zero value in this counter may indicate an opportunity to 7340** improvement performance by adding permanent indices that do not 7341** need to be reinitialized each time the statement is run.</dd> 7342** 7343** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7344** <dd>^This is the number of virtual machine operations executed 7345** by the prepared statement if that number is less than or equal 7346** to 2147483647. The number of virtual machine operations can be 7347** used as a proxy for the total work done by the prepared statement. 7348** If the number of virtual machine operations exceeds 2147483647 7349** then the value returned by this statement status code is undefined. 7350** 7351** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7352** <dd>^This is the number of times that the prepare statement has been 7353** automatically regenerated due to schema changes or change to 7354** [bound parameters] that might affect the query plan. 7355** 7356** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7357** <dd>^This is the number of times that the prepared statement has 7358** been run. A single "run" for the purposes of this counter is one 7359** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7360** The counter is incremented on the first [sqlite3_step()] call of each 7361** cycle. 7362** 7363** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7364** <dd>^This is the approximate number of bytes of heap memory 7365** used to store the prepared statement. ^This value is not actually 7366** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7367** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7368** </dd> 7369** </dl> 7370*/ 7371#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7372#define SQLITE_STMTSTATUS_SORT 2 7373#define SQLITE_STMTSTATUS_AUTOINDEX 3 7374#define SQLITE_STMTSTATUS_VM_STEP 4 7375#define SQLITE_STMTSTATUS_REPREPARE 5 7376#define SQLITE_STMTSTATUS_RUN 6 7377#define SQLITE_STMTSTATUS_MEMUSED 99 7378 7379/* 7380** CAPI3REF: Custom Page Cache Object 7381** 7382** The sqlite3_pcache type is opaque. It is implemented by 7383** the pluggable module. The SQLite core has no knowledge of 7384** its size or internal structure and never deals with the 7385** sqlite3_pcache object except by holding and passing pointers 7386** to the object. 7387** 7388** See [sqlite3_pcache_methods2] for additional information. 7389*/ 7390typedef struct sqlite3_pcache sqlite3_pcache; 7391 7392/* 7393** CAPI3REF: Custom Page Cache Object 7394** 7395** The sqlite3_pcache_page object represents a single page in the 7396** page cache. The page cache will allocate instances of this 7397** object. Various methods of the page cache use pointers to instances 7398** of this object as parameters or as their return value. 7399** 7400** See [sqlite3_pcache_methods2] for additional information. 7401*/ 7402typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7403struct sqlite3_pcache_page { 7404 void *pBuf; /* The content of the page */ 7405 void *pExtra; /* Extra information associated with the page */ 7406}; 7407 7408/* 7409** CAPI3REF: Application Defined Page Cache. 7410** KEYWORDS: {page cache} 7411** 7412** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7413** register an alternative page cache implementation by passing in an 7414** instance of the sqlite3_pcache_methods2 structure.)^ 7415** In many applications, most of the heap memory allocated by 7416** SQLite is used for the page cache. 7417** By implementing a 7418** custom page cache using this API, an application can better control 7419** the amount of memory consumed by SQLite, the way in which 7420** that memory is allocated and released, and the policies used to 7421** determine exactly which parts of a database file are cached and for 7422** how long. 7423** 7424** The alternative page cache mechanism is an 7425** extreme measure that is only needed by the most demanding applications. 7426** The built-in page cache is recommended for most uses. 7427** 7428** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7429** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7430** the application may discard the parameter after the call to 7431** [sqlite3_config()] returns.)^ 7432** 7433** [[the xInit() page cache method]] 7434** ^(The xInit() method is called once for each effective 7435** call to [sqlite3_initialize()])^ 7436** (usually only once during the lifetime of the process). ^(The xInit() 7437** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7438** The intent of the xInit() method is to set up global data structures 7439** required by the custom page cache implementation. 7440** ^(If the xInit() method is NULL, then the 7441** built-in default page cache is used instead of the application defined 7442** page cache.)^ 7443** 7444** [[the xShutdown() page cache method]] 7445** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7446** It can be used to clean up 7447** any outstanding resources before process shutdown, if required. 7448** ^The xShutdown() method may be NULL. 7449** 7450** ^SQLite automatically serializes calls to the xInit method, 7451** so the xInit method need not be threadsafe. ^The 7452** xShutdown method is only called from [sqlite3_shutdown()] so it does 7453** not need to be threadsafe either. All other methods must be threadsafe 7454** in multithreaded applications. 7455** 7456** ^SQLite will never invoke xInit() more than once without an intervening 7457** call to xShutdown(). 7458** 7459** [[the xCreate() page cache methods]] 7460** ^SQLite invokes the xCreate() method to construct a new cache instance. 7461** SQLite will typically create one cache instance for each open database file, 7462** though this is not guaranteed. ^The 7463** first parameter, szPage, is the size in bytes of the pages that must 7464** be allocated by the cache. ^szPage will always a power of two. ^The 7465** second parameter szExtra is a number of bytes of extra storage 7466** associated with each page cache entry. ^The szExtra parameter will 7467** a number less than 250. SQLite will use the 7468** extra szExtra bytes on each page to store metadata about the underlying 7469** database page on disk. The value passed into szExtra depends 7470** on the SQLite version, the target platform, and how SQLite was compiled. 7471** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7472** created will be used to cache database pages of a file stored on disk, or 7473** false if it is used for an in-memory database. The cache implementation 7474** does not have to do anything special based with the value of bPurgeable; 7475** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7476** never invoke xUnpin() except to deliberately delete a page. 7477** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7478** false will always have the "discard" flag set to true. 7479** ^Hence, a cache created with bPurgeable false will 7480** never contain any unpinned pages. 7481** 7482** [[the xCachesize() page cache method]] 7483** ^(The xCachesize() method may be called at any time by SQLite to set the 7484** suggested maximum cache-size (number of pages stored by) the cache 7485** instance passed as the first argument. This is the value configured using 7486** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7487** parameter, the implementation is not required to do anything with this 7488** value; it is advisory only. 7489** 7490** [[the xPagecount() page cache methods]] 7491** The xPagecount() method must return the number of pages currently 7492** stored in the cache, both pinned and unpinned. 7493** 7494** [[the xFetch() page cache methods]] 7495** The xFetch() method locates a page in the cache and returns a pointer to 7496** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7497** The pBuf element of the returned sqlite3_pcache_page object will be a 7498** pointer to a buffer of szPage bytes used to store the content of a 7499** single database page. The pExtra element of sqlite3_pcache_page will be 7500** a pointer to the szExtra bytes of extra storage that SQLite has requested 7501** for each entry in the page cache. 7502** 7503** The page to be fetched is determined by the key. ^The minimum key value 7504** is 1. After it has been retrieved using xFetch, the page is considered 7505** to be "pinned". 7506** 7507** If the requested page is already in the page cache, then the page cache 7508** implementation must return a pointer to the page buffer with its content 7509** intact. If the requested page is not already in the cache, then the 7510** cache implementation should use the value of the createFlag 7511** parameter to help it determined what action to take: 7512** 7513** <table border=1 width=85% align=center> 7514** <tr><th> createFlag <th> Behavior when page is not already in cache 7515** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7516** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7517** Otherwise return NULL. 7518** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7519** NULL if allocating a new page is effectively impossible. 7520** </table> 7521** 7522** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7523** will only use a createFlag of 2 after a prior call with a createFlag of 1 7524** failed.)^ In between the to xFetch() calls, SQLite may 7525** attempt to unpin one or more cache pages by spilling the content of 7526** pinned pages to disk and synching the operating system disk cache. 7527** 7528** [[the xUnpin() page cache method]] 7529** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7530** as its second argument. If the third parameter, discard, is non-zero, 7531** then the page must be evicted from the cache. 7532** ^If the discard parameter is 7533** zero, then the page may be discarded or retained at the discretion of 7534** page cache implementation. ^The page cache implementation 7535** may choose to evict unpinned pages at any time. 7536** 7537** The cache must not perform any reference counting. A single 7538** call to xUnpin() unpins the page regardless of the number of prior calls 7539** to xFetch(). 7540** 7541** [[the xRekey() page cache methods]] 7542** The xRekey() method is used to change the key value associated with the 7543** page passed as the second argument. If the cache 7544** previously contains an entry associated with newKey, it must be 7545** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7546** to be pinned. 7547** 7548** When SQLite calls the xTruncate() method, the cache must discard all 7549** existing cache entries with page numbers (keys) greater than or equal 7550** to the value of the iLimit parameter passed to xTruncate(). If any 7551** of these pages are pinned, they are implicitly unpinned, meaning that 7552** they can be safely discarded. 7553** 7554** [[the xDestroy() page cache method]] 7555** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7556** All resources associated with the specified cache should be freed. ^After 7557** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7558** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7559** functions. 7560** 7561** [[the xShrink() page cache method]] 7562** ^SQLite invokes the xShrink() method when it wants the page cache to 7563** free up as much of heap memory as possible. The page cache implementation 7564** is not obligated to free any memory, but well-behaved implementations should 7565** do their best. 7566*/ 7567typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7568struct sqlite3_pcache_methods2 { 7569 int iVersion; 7570 void *pArg; 7571 int (*xInit)(void*); 7572 void (*xShutdown)(void*); 7573 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7574 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7575 int (*xPagecount)(sqlite3_pcache*); 7576 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7577 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7578 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7579 unsigned oldKey, unsigned newKey); 7580 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7581 void (*xDestroy)(sqlite3_pcache*); 7582 void (*xShrink)(sqlite3_pcache*); 7583}; 7584 7585/* 7586** This is the obsolete pcache_methods object that has now been replaced 7587** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7588** retained in the header file for backwards compatibility only. 7589*/ 7590typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7591struct sqlite3_pcache_methods { 7592 void *pArg; 7593 int (*xInit)(void*); 7594 void (*xShutdown)(void*); 7595 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7596 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7597 int (*xPagecount)(sqlite3_pcache*); 7598 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7599 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7600 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7601 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7602 void (*xDestroy)(sqlite3_pcache*); 7603}; 7604 7605 7606/* 7607** CAPI3REF: Online Backup Object 7608** 7609** The sqlite3_backup object records state information about an ongoing 7610** online backup operation. ^The sqlite3_backup object is created by 7611** a call to [sqlite3_backup_init()] and is destroyed by a call to 7612** [sqlite3_backup_finish()]. 7613** 7614** See Also: [Using the SQLite Online Backup API] 7615*/ 7616typedef struct sqlite3_backup sqlite3_backup; 7617 7618/* 7619** CAPI3REF: Online Backup API. 7620** 7621** The backup API copies the content of one database into another. 7622** It is useful either for creating backups of databases or 7623** for copying in-memory databases to or from persistent files. 7624** 7625** See Also: [Using the SQLite Online Backup API] 7626** 7627** ^SQLite holds a write transaction open on the destination database file 7628** for the duration of the backup operation. 7629** ^The source database is read-locked only while it is being read; 7630** it is not locked continuously for the entire backup operation. 7631** ^Thus, the backup may be performed on a live source database without 7632** preventing other database connections from 7633** reading or writing to the source database while the backup is underway. 7634** 7635** ^(To perform a backup operation: 7636** <ol> 7637** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7638** backup, 7639** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7640** the data between the two databases, and finally 7641** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7642** associated with the backup operation. 7643** </ol>)^ 7644** There should be exactly one call to sqlite3_backup_finish() for each 7645** successful call to sqlite3_backup_init(). 7646** 7647** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7648** 7649** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7650** [database connection] associated with the destination database 7651** and the database name, respectively. 7652** ^The database name is "main" for the main database, "temp" for the 7653** temporary database, or the name specified after the AS keyword in 7654** an [ATTACH] statement for an attached database. 7655** ^The S and M arguments passed to 7656** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7657** and database name of the source database, respectively. 7658** ^The source and destination [database connections] (parameters S and D) 7659** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7660** an error. 7661** 7662** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7663** there is already a read or read-write transaction open on the 7664** destination database. 7665** 7666** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7667** returned and an error code and error message are stored in the 7668** destination [database connection] D. 7669** ^The error code and message for the failed call to sqlite3_backup_init() 7670** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7671** [sqlite3_errmsg16()] functions. 7672** ^A successful call to sqlite3_backup_init() returns a pointer to an 7673** [sqlite3_backup] object. 7674** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7675** sqlite3_backup_finish() functions to perform the specified backup 7676** operation. 7677** 7678** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7679** 7680** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7681** the source and destination databases specified by [sqlite3_backup] object B. 7682** ^If N is negative, all remaining source pages are copied. 7683** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7684** are still more pages to be copied, then the function returns [SQLITE_OK]. 7685** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7686** from source to destination, then it returns [SQLITE_DONE]. 7687** ^If an error occurs while running sqlite3_backup_step(B,N), 7688** then an [error code] is returned. ^As well as [SQLITE_OK] and 7689** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7690** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7691** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7692** 7693** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7694** <ol> 7695** <li> the destination database was opened read-only, or 7696** <li> the destination database is using write-ahead-log journaling 7697** and the destination and source page sizes differ, or 7698** <li> the destination database is an in-memory database and the 7699** destination and source page sizes differ. 7700** </ol>)^ 7701** 7702** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7703** the [sqlite3_busy_handler | busy-handler function] 7704** is invoked (if one is specified). ^If the 7705** busy-handler returns non-zero before the lock is available, then 7706** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7707** sqlite3_backup_step() can be retried later. ^If the source 7708** [database connection] 7709** is being used to write to the source database when sqlite3_backup_step() 7710** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7711** case the call to sqlite3_backup_step() can be retried later on. ^(If 7712** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7713** [SQLITE_READONLY] is returned, then 7714** there is no point in retrying the call to sqlite3_backup_step(). These 7715** errors are considered fatal.)^ The application must accept 7716** that the backup operation has failed and pass the backup operation handle 7717** to the sqlite3_backup_finish() to release associated resources. 7718** 7719** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7720** on the destination file. ^The exclusive lock is not released until either 7721** sqlite3_backup_finish() is called or the backup operation is complete 7722** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7723** sqlite3_backup_step() obtains a [shared lock] on the source database that 7724** lasts for the duration of the sqlite3_backup_step() call. 7725** ^Because the source database is not locked between calls to 7726** sqlite3_backup_step(), the source database may be modified mid-way 7727** through the backup process. ^If the source database is modified by an 7728** external process or via a database connection other than the one being 7729** used by the backup operation, then the backup will be automatically 7730** restarted by the next call to sqlite3_backup_step(). ^If the source 7731** database is modified by the using the same database connection as is used 7732** by the backup operation, then the backup database is automatically 7733** updated at the same time. 7734** 7735** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7736** 7737** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7738** application wishes to abandon the backup operation, the application 7739** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7740** ^The sqlite3_backup_finish() interfaces releases all 7741** resources associated with the [sqlite3_backup] object. 7742** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7743** active write-transaction on the destination database is rolled back. 7744** The [sqlite3_backup] object is invalid 7745** and may not be used following a call to sqlite3_backup_finish(). 7746** 7747** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7748** sqlite3_backup_step() errors occurred, regardless or whether or not 7749** sqlite3_backup_step() completed. 7750** ^If an out-of-memory condition or IO error occurred during any prior 7751** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7752** sqlite3_backup_finish() returns the corresponding [error code]. 7753** 7754** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7755** is not a permanent error and does not affect the return value of 7756** sqlite3_backup_finish(). 7757** 7758** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7759** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7760** 7761** ^The sqlite3_backup_remaining() routine returns the number of pages still 7762** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7763** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7764** in the source database at the conclusion of the most recent 7765** sqlite3_backup_step(). 7766** ^(The values returned by these functions are only updated by 7767** sqlite3_backup_step(). If the source database is modified in a way that 7768** changes the size of the source database or the number of pages remaining, 7769** those changes are not reflected in the output of sqlite3_backup_pagecount() 7770** and sqlite3_backup_remaining() until after the next 7771** sqlite3_backup_step().)^ 7772** 7773** <b>Concurrent Usage of Database Handles</b> 7774** 7775** ^The source [database connection] may be used by the application for other 7776** purposes while a backup operation is underway or being initialized. 7777** ^If SQLite is compiled and configured to support threadsafe database 7778** connections, then the source database connection may be used concurrently 7779** from within other threads. 7780** 7781** However, the application must guarantee that the destination 7782** [database connection] is not passed to any other API (by any thread) after 7783** sqlite3_backup_init() is called and before the corresponding call to 7784** sqlite3_backup_finish(). SQLite does not currently check to see 7785** if the application incorrectly accesses the destination [database connection] 7786** and so no error code is reported, but the operations may malfunction 7787** nevertheless. Use of the destination database connection while a 7788** backup is in progress might also also cause a mutex deadlock. 7789** 7790** If running in [shared cache mode], the application must 7791** guarantee that the shared cache used by the destination database 7792** is not accessed while the backup is running. In practice this means 7793** that the application must guarantee that the disk file being 7794** backed up to is not accessed by any connection within the process, 7795** not just the specific connection that was passed to sqlite3_backup_init(). 7796** 7797** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7798** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7799** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7800** APIs are not strictly speaking threadsafe. If they are invoked at the 7801** same time as another thread is invoking sqlite3_backup_step() it is 7802** possible that they return invalid values. 7803*/ 7804sqlite3_backup *sqlite3_backup_init( 7805 sqlite3 *pDest, /* Destination database handle */ 7806 const char *zDestName, /* Destination database name */ 7807 sqlite3 *pSource, /* Source database handle */ 7808 const char *zSourceName /* Source database name */ 7809); 7810int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7811int sqlite3_backup_finish(sqlite3_backup *p); 7812int sqlite3_backup_remaining(sqlite3_backup *p); 7813int sqlite3_backup_pagecount(sqlite3_backup *p); 7814 7815/* 7816** CAPI3REF: Unlock Notification 7817** METHOD: sqlite3 7818** 7819** ^When running in shared-cache mode, a database operation may fail with 7820** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7821** individual tables within the shared-cache cannot be obtained. See 7822** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7823** ^This API may be used to register a callback that SQLite will invoke 7824** when the connection currently holding the required lock relinquishes it. 7825** ^This API is only available if the library was compiled with the 7826** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7827** 7828** See Also: [Using the SQLite Unlock Notification Feature]. 7829** 7830** ^Shared-cache locks are released when a database connection concludes 7831** its current transaction, either by committing it or rolling it back. 7832** 7833** ^When a connection (known as the blocked connection) fails to obtain a 7834** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7835** identity of the database connection (the blocking connection) that 7836** has locked the required resource is stored internally. ^After an 7837** application receives an SQLITE_LOCKED error, it may call the 7838** sqlite3_unlock_notify() method with the blocked connection handle as 7839** the first argument to register for a callback that will be invoked 7840** when the blocking connections current transaction is concluded. ^The 7841** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7842** call that concludes the blocking connections transaction. 7843** 7844** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7845** there is a chance that the blocking connection will have already 7846** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7847** If this happens, then the specified callback is invoked immediately, 7848** from within the call to sqlite3_unlock_notify().)^ 7849** 7850** ^If the blocked connection is attempting to obtain a write-lock on a 7851** shared-cache table, and more than one other connection currently holds 7852** a read-lock on the same table, then SQLite arbitrarily selects one of 7853** the other connections to use as the blocking connection. 7854** 7855** ^(There may be at most one unlock-notify callback registered by a 7856** blocked connection. If sqlite3_unlock_notify() is called when the 7857** blocked connection already has a registered unlock-notify callback, 7858** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7859** called with a NULL pointer as its second argument, then any existing 7860** unlock-notify callback is canceled. ^The blocked connections 7861** unlock-notify callback may also be canceled by closing the blocked 7862** connection using [sqlite3_close()]. 7863** 7864** The unlock-notify callback is not reentrant. If an application invokes 7865** any sqlite3_xxx API functions from within an unlock-notify callback, a 7866** crash or deadlock may be the result. 7867** 7868** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7869** returns SQLITE_OK. 7870** 7871** <b>Callback Invocation Details</b> 7872** 7873** When an unlock-notify callback is registered, the application provides a 7874** single void* pointer that is passed to the callback when it is invoked. 7875** However, the signature of the callback function allows SQLite to pass 7876** it an array of void* context pointers. The first argument passed to 7877** an unlock-notify callback is a pointer to an array of void* pointers, 7878** and the second is the number of entries in the array. 7879** 7880** When a blocking connections transaction is concluded, there may be 7881** more than one blocked connection that has registered for an unlock-notify 7882** callback. ^If two or more such blocked connections have specified the 7883** same callback function, then instead of invoking the callback function 7884** multiple times, it is invoked once with the set of void* context pointers 7885** specified by the blocked connections bundled together into an array. 7886** This gives the application an opportunity to prioritize any actions 7887** related to the set of unblocked database connections. 7888** 7889** <b>Deadlock Detection</b> 7890** 7891** Assuming that after registering for an unlock-notify callback a 7892** database waits for the callback to be issued before taking any further 7893** action (a reasonable assumption), then using this API may cause the 7894** application to deadlock. For example, if connection X is waiting for 7895** connection Y's transaction to be concluded, and similarly connection 7896** Y is waiting on connection X's transaction, then neither connection 7897** will proceed and the system may remain deadlocked indefinitely. 7898** 7899** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7900** detection. ^If a given call to sqlite3_unlock_notify() would put the 7901** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7902** unlock-notify callback is registered. The system is said to be in 7903** a deadlocked state if connection A has registered for an unlock-notify 7904** callback on the conclusion of connection B's transaction, and connection 7905** B has itself registered for an unlock-notify callback when connection 7906** A's transaction is concluded. ^Indirect deadlock is also detected, so 7907** the system is also considered to be deadlocked if connection B has 7908** registered for an unlock-notify callback on the conclusion of connection 7909** C's transaction, where connection C is waiting on connection A. ^Any 7910** number of levels of indirection are allowed. 7911** 7912** <b>The "DROP TABLE" Exception</b> 7913** 7914** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7915** always appropriate to call sqlite3_unlock_notify(). There is however, 7916** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7917** SQLite checks if there are any currently executing SELECT statements 7918** that belong to the same connection. If there are, SQLITE_LOCKED is 7919** returned. In this case there is no "blocking connection", so invoking 7920** sqlite3_unlock_notify() results in the unlock-notify callback being 7921** invoked immediately. If the application then re-attempts the "DROP TABLE" 7922** or "DROP INDEX" query, an infinite loop might be the result. 7923** 7924** One way around this problem is to check the extended error code returned 7925** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7926** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7927** the special "DROP TABLE/INDEX" case, the extended error code is just 7928** SQLITE_LOCKED.)^ 7929*/ 7930int sqlite3_unlock_notify( 7931 sqlite3 *pBlocked, /* Waiting connection */ 7932 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7933 void *pNotifyArg /* Argument to pass to xNotify */ 7934); 7935 7936 7937/* 7938** CAPI3REF: String Comparison 7939** 7940** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7941** and extensions to compare the contents of two buffers containing UTF-8 7942** strings in a case-independent fashion, using the same definition of "case 7943** independence" that SQLite uses internally when comparing identifiers. 7944*/ 7945int sqlite3_stricmp(const char *, const char *); 7946int sqlite3_strnicmp(const char *, const char *, int); 7947 7948/* 7949** CAPI3REF: String Globbing 7950* 7951** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7952** string X matches the [GLOB] pattern P. 7953** ^The definition of [GLOB] pattern matching used in 7954** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7955** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7956** is case sensitive. 7957** 7958** Note that this routine returns zero on a match and non-zero if the strings 7959** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7960** 7961** See also: [sqlite3_strlike()]. 7962*/ 7963int sqlite3_strglob(const char *zGlob, const char *zStr); 7964 7965/* 7966** CAPI3REF: String LIKE Matching 7967* 7968** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7969** string X matches the [LIKE] pattern P with escape character E. 7970** ^The definition of [LIKE] pattern matching used in 7971** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7972** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7973** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7974** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7975** insensitive - equivalent upper and lower case ASCII characters match 7976** one another. 7977** 7978** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7979** only ASCII characters are case folded. 7980** 7981** Note that this routine returns zero on a match and non-zero if the strings 7982** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7983** 7984** See also: [sqlite3_strglob()]. 7985*/ 7986int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7987 7988/* 7989** CAPI3REF: Error Logging Interface 7990** 7991** ^The [sqlite3_log()] interface writes a message into the [error log] 7992** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7993** ^If logging is enabled, the zFormat string and subsequent arguments are 7994** used with [sqlite3_snprintf()] to generate the final output string. 7995** 7996** The sqlite3_log() interface is intended for use by extensions such as 7997** virtual tables, collating functions, and SQL functions. While there is 7998** nothing to prevent an application from calling sqlite3_log(), doing so 7999** is considered bad form. 8000** 8001** The zFormat string must not be NULL. 8002** 8003** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8004** will not use dynamically allocated memory. The log message is stored in 8005** a fixed-length buffer on the stack. If the log message is longer than 8006** a few hundred characters, it will be truncated to the length of the 8007** buffer. 8008*/ 8009void sqlite3_log(int iErrCode, const char *zFormat, ...); 8010 8011/* 8012** CAPI3REF: Write-Ahead Log Commit Hook 8013** METHOD: sqlite3 8014** 8015** ^The [sqlite3_wal_hook()] function is used to register a callback that 8016** is invoked each time data is committed to a database in wal mode. 8017** 8018** ^(The callback is invoked by SQLite after the commit has taken place and 8019** the associated write-lock on the database released)^, so the implementation 8020** may read, write or [checkpoint] the database as required. 8021** 8022** ^The first parameter passed to the callback function when it is invoked 8023** is a copy of the third parameter passed to sqlite3_wal_hook() when 8024** registering the callback. ^The second is a copy of the database handle. 8025** ^The third parameter is the name of the database that was written to - 8026** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8027** is the number of pages currently in the write-ahead log file, 8028** including those that were just committed. 8029** 8030** The callback function should normally return [SQLITE_OK]. ^If an error 8031** code is returned, that error will propagate back up through the 8032** SQLite code base to cause the statement that provoked the callback 8033** to report an error, though the commit will have still occurred. If the 8034** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8035** that does not correspond to any valid SQLite error code, the results 8036** are undefined. 8037** 8038** A single database handle may have at most a single write-ahead log callback 8039** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8040** previously registered write-ahead log callback. ^Note that the 8041** [sqlite3_wal_autocheckpoint()] interface and the 8042** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8043** overwrite any prior [sqlite3_wal_hook()] settings. 8044*/ 8045void *sqlite3_wal_hook( 8046 sqlite3*, 8047 int(*)(void *,sqlite3*,const char*,int), 8048 void* 8049); 8050 8051/* 8052** CAPI3REF: Configure an auto-checkpoint 8053** METHOD: sqlite3 8054** 8055** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8056** [sqlite3_wal_hook()] that causes any database on [database connection] D 8057** to automatically [checkpoint] 8058** after committing a transaction if there are N or 8059** more frames in the [write-ahead log] file. ^Passing zero or 8060** a negative value as the nFrame parameter disables automatic 8061** checkpoints entirely. 8062** 8063** ^The callback registered by this function replaces any existing callback 8064** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8065** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8066** configured by this function. 8067** 8068** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8069** from SQL. 8070** 8071** ^Checkpoints initiated by this mechanism are 8072** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8073** 8074** ^Every new [database connection] defaults to having the auto-checkpoint 8075** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8076** pages. The use of this interface 8077** is only necessary if the default setting is found to be suboptimal 8078** for a particular application. 8079*/ 8080int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8081 8082/* 8083** CAPI3REF: Checkpoint a database 8084** METHOD: sqlite3 8085** 8086** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8087** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8088** 8089** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8090** [write-ahead log] for database X on [database connection] D to be 8091** transferred into the database file and for the write-ahead log to 8092** be reset. See the [checkpointing] documentation for addition 8093** information. 8094** 8095** This interface used to be the only way to cause a checkpoint to 8096** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8097** interface was added. This interface is retained for backwards 8098** compatibility and as a convenience for applications that need to manually 8099** start a callback but which do not need the full power (and corresponding 8100** complication) of [sqlite3_wal_checkpoint_v2()]. 8101*/ 8102int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8103 8104/* 8105** CAPI3REF: Checkpoint a database 8106** METHOD: sqlite3 8107** 8108** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8109** operation on database X of [database connection] D in mode M. Status 8110** information is written back into integers pointed to by L and C.)^ 8111** ^(The M parameter must be a valid [checkpoint mode]:)^ 8112** 8113** <dl> 8114** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8115** ^Checkpoint as many frames as possible without waiting for any database 8116** readers or writers to finish, then sync the database file if all frames 8117** in the log were checkpointed. ^The [busy-handler callback] 8118** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8119** ^On the other hand, passive mode might leave the checkpoint unfinished 8120** if there are concurrent readers or writers. 8121** 8122** <dt>SQLITE_CHECKPOINT_FULL<dd> 8123** ^This mode blocks (it invokes the 8124** [sqlite3_busy_handler|busy-handler callback]) until there is no 8125** database writer and all readers are reading from the most recent database 8126** snapshot. ^It then checkpoints all frames in the log file and syncs the 8127** database file. ^This mode blocks new database writers while it is pending, 8128** but new database readers are allowed to continue unimpeded. 8129** 8130** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8131** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8132** that after checkpointing the log file it blocks (calls the 8133** [busy-handler callback]) 8134** until all readers are reading from the database file only. ^This ensures 8135** that the next writer will restart the log file from the beginning. 8136** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8137** database writer attempts while it is pending, but does not impede readers. 8138** 8139** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8140** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8141** addition that it also truncates the log file to zero bytes just prior 8142** to a successful return. 8143** </dl> 8144** 8145** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8146** the log file or to -1 if the checkpoint could not run because 8147** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8148** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8149** log file (including any that were already checkpointed before the function 8150** was called) or to -1 if the checkpoint could not run due to an error or 8151** because the database is not in WAL mode. ^Note that upon successful 8152** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8153** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8154** 8155** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8156** any other process is running a checkpoint operation at the same time, the 8157** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8158** busy-handler configured, it will not be invoked in this case. 8159** 8160** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8161** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8162** obtained immediately, and a busy-handler is configured, it is invoked and 8163** the writer lock retried until either the busy-handler returns 0 or the lock 8164** is successfully obtained. ^The busy-handler is also invoked while waiting for 8165** database readers as described above. ^If the busy-handler returns 0 before 8166** the writer lock is obtained or while waiting for database readers, the 8167** checkpoint operation proceeds from that point in the same way as 8168** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8169** without blocking any further. ^SQLITE_BUSY is returned in this case. 8170** 8171** ^If parameter zDb is NULL or points to a zero length string, then the 8172** specified operation is attempted on all WAL databases [attached] to 8173** [database connection] db. In this case the 8174** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8175** an SQLITE_BUSY error is encountered when processing one or more of the 8176** attached WAL databases, the operation is still attempted on any remaining 8177** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8178** error occurs while processing an attached database, processing is abandoned 8179** and the error code is returned to the caller immediately. ^If no error 8180** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8181** databases, SQLITE_OK is returned. 8182** 8183** ^If database zDb is the name of an attached database that is not in WAL 8184** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8185** zDb is not NULL (or a zero length string) and is not the name of any 8186** attached database, SQLITE_ERROR is returned to the caller. 8187** 8188** ^Unless it returns SQLITE_MISUSE, 8189** the sqlite3_wal_checkpoint_v2() interface 8190** sets the error information that is queried by 8191** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8192** 8193** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8194** from SQL. 8195*/ 8196int sqlite3_wal_checkpoint_v2( 8197 sqlite3 *db, /* Database handle */ 8198 const char *zDb, /* Name of attached database (or NULL) */ 8199 int eMode, /* SQLITE_CHECKPOINT_* value */ 8200 int *pnLog, /* OUT: Size of WAL log in frames */ 8201 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8202); 8203 8204/* 8205** CAPI3REF: Checkpoint Mode Values 8206** KEYWORDS: {checkpoint mode} 8207** 8208** These constants define all valid values for the "checkpoint mode" passed 8209** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8210** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8211** meaning of each of these checkpoint modes. 8212*/ 8213#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8214#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8215#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8216#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8217 8218/* 8219** CAPI3REF: Virtual Table Interface Configuration 8220** 8221** This function may be called by either the [xConnect] or [xCreate] method 8222** of a [virtual table] implementation to configure 8223** various facets of the virtual table interface. 8224** 8225** If this interface is invoked outside the context of an xConnect or 8226** xCreate virtual table method then the behavior is undefined. 8227** 8228** At present, there is only one option that may be configured using 8229** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8230** may be added in the future. 8231*/ 8232int sqlite3_vtab_config(sqlite3*, int op, ...); 8233 8234/* 8235** CAPI3REF: Virtual Table Configuration Options 8236** 8237** These macros define the various options to the 8238** [sqlite3_vtab_config()] interface that [virtual table] implementations 8239** can use to customize and optimize their behavior. 8240** 8241** <dl> 8242** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8243** <dd>Calls of the form 8244** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8245** where X is an integer. If X is zero, then the [virtual table] whose 8246** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8247** support constraints. In this configuration (which is the default) if 8248** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8249** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8250** specified as part of the users SQL statement, regardless of the actual 8251** ON CONFLICT mode specified. 8252** 8253** If X is non-zero, then the virtual table implementation guarantees 8254** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8255** any modifications to internal or persistent data structures have been made. 8256** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8257** is able to roll back a statement or database transaction, and abandon 8258** or continue processing the current SQL statement as appropriate. 8259** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8260** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8261** had been ABORT. 8262** 8263** Virtual table implementations that are required to handle OR REPLACE 8264** must do so within the [xUpdate] method. If a call to the 8265** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8266** CONFLICT policy is REPLACE, the virtual table implementation should 8267** silently replace the appropriate rows within the xUpdate callback and 8268** return SQLITE_OK. Or, if this is not possible, it may return 8269** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8270** constraint handling. 8271** </dl> 8272*/ 8273#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8274 8275/* 8276** CAPI3REF: Determine The Virtual Table Conflict Policy 8277** 8278** This function may only be called from within a call to the [xUpdate] method 8279** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8280** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8281** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8282** of the SQL statement that triggered the call to the [xUpdate] method of the 8283** [virtual table]. 8284*/ 8285int sqlite3_vtab_on_conflict(sqlite3 *); 8286 8287/* 8288** CAPI3REF: Conflict resolution modes 8289** KEYWORDS: {conflict resolution mode} 8290** 8291** These constants are returned by [sqlite3_vtab_on_conflict()] to 8292** inform a [virtual table] implementation what the [ON CONFLICT] mode 8293** is for the SQL statement being evaluated. 8294** 8295** Note that the [SQLITE_IGNORE] constant is also used as a potential 8296** return value from the [sqlite3_set_authorizer()] callback and that 8297** [SQLITE_ABORT] is also a [result code]. 8298*/ 8299#define SQLITE_ROLLBACK 1 8300/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8301#define SQLITE_FAIL 3 8302/* #define SQLITE_ABORT 4 // Also an error code */ 8303#define SQLITE_REPLACE 5 8304 8305/* 8306** CAPI3REF: Prepared Statement Scan Status Opcodes 8307** KEYWORDS: {scanstatus options} 8308** 8309** The following constants can be used for the T parameter to the 8310** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8311** different metric for sqlite3_stmt_scanstatus() to return. 8312** 8313** When the value returned to V is a string, space to hold that string is 8314** managed by the prepared statement S and will be automatically freed when 8315** S is finalized. 8316** 8317** <dl> 8318** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8319** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8320** set to the total number of times that the X-th loop has run.</dd> 8321** 8322** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8323** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8324** to the total number of rows examined by all iterations of the X-th loop.</dd> 8325** 8326** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8327** <dd>^The "double" variable pointed to by the T parameter will be set to the 8328** query planner's estimate for the average number of rows output from each 8329** iteration of the X-th loop. If the query planner's estimates was accurate, 8330** then this value will approximate the quotient NVISIT/NLOOP and the 8331** product of this value for all prior loops with the same SELECTID will 8332** be the NLOOP value for the current loop. 8333** 8334** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8335** <dd>^The "const char *" variable pointed to by the T parameter will be set 8336** to a zero-terminated UTF-8 string containing the name of the index or table 8337** used for the X-th loop. 8338** 8339** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8340** <dd>^The "const char *" variable pointed to by the T parameter will be set 8341** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8342** description for the X-th loop. 8343** 8344** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8345** <dd>^The "int" variable pointed to by the T parameter will be set to the 8346** "select-id" for the X-th loop. The select-id identifies which query or 8347** subquery the loop is part of. The main query has a select-id of zero. 8348** The select-id is the same value as is output in the first column 8349** of an [EXPLAIN QUERY PLAN] query. 8350** </dl> 8351*/ 8352#define SQLITE_SCANSTAT_NLOOP 0 8353#define SQLITE_SCANSTAT_NVISIT 1 8354#define SQLITE_SCANSTAT_EST 2 8355#define SQLITE_SCANSTAT_NAME 3 8356#define SQLITE_SCANSTAT_EXPLAIN 4 8357#define SQLITE_SCANSTAT_SELECTID 5 8358 8359/* 8360** CAPI3REF: Prepared Statement Scan Status 8361** METHOD: sqlite3_stmt 8362** 8363** This interface returns information about the predicted and measured 8364** performance for pStmt. Advanced applications can use this 8365** interface to compare the predicted and the measured performance and 8366** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8367** 8368** Since this interface is expected to be rarely used, it is only 8369** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8370** compile-time option. 8371** 8372** The "iScanStatusOp" parameter determines which status information to return. 8373** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8374** of this interface is undefined. 8375** ^The requested measurement is written into a variable pointed to by 8376** the "pOut" parameter. 8377** Parameter "idx" identifies the specific loop to retrieve statistics for. 8378** Loops are numbered starting from zero. ^If idx is out of range - less than 8379** zero or greater than or equal to the total number of loops used to implement 8380** the statement - a non-zero value is returned and the variable that pOut 8381** points to is unchanged. 8382** 8383** ^Statistics might not be available for all loops in all statements. ^In cases 8384** where there exist loops with no available statistics, this function behaves 8385** as if the loop did not exist - it returns non-zero and leave the variable 8386** that pOut points to unchanged. 8387** 8388** See also: [sqlite3_stmt_scanstatus_reset()] 8389*/ 8390int sqlite3_stmt_scanstatus( 8391 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8392 int idx, /* Index of loop to report on */ 8393 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8394 void *pOut /* Result written here */ 8395); 8396 8397/* 8398** CAPI3REF: Zero Scan-Status Counters 8399** METHOD: sqlite3_stmt 8400** 8401** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8402** 8403** This API is only available if the library is built with pre-processor 8404** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8405*/ 8406void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8407 8408/* 8409** CAPI3REF: Flush caches to disk mid-transaction 8410** 8411** ^If a write-transaction is open on [database connection] D when the 8412** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8413** pages in the pager-cache that are not currently in use are written out 8414** to disk. A dirty page may be in use if a database cursor created by an 8415** active SQL statement is reading from it, or if it is page 1 of a database 8416** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8417** interface flushes caches for all schemas - "main", "temp", and 8418** any [attached] databases. 8419** 8420** ^If this function needs to obtain extra database locks before dirty pages 8421** can be flushed to disk, it does so. ^If those locks cannot be obtained 8422** immediately and there is a busy-handler callback configured, it is invoked 8423** in the usual manner. ^If the required lock still cannot be obtained, then 8424** the database is skipped and an attempt made to flush any dirty pages 8425** belonging to the next (if any) database. ^If any databases are skipped 8426** because locks cannot be obtained, but no other error occurs, this 8427** function returns SQLITE_BUSY. 8428** 8429** ^If any other error occurs while flushing dirty pages to disk (for 8430** example an IO error or out-of-memory condition), then processing is 8431** abandoned and an SQLite [error code] is returned to the caller immediately. 8432** 8433** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8434** 8435** ^This function does not set the database handle error code or message 8436** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8437*/ 8438int sqlite3_db_cacheflush(sqlite3*); 8439 8440/* 8441** CAPI3REF: The pre-update hook. 8442** 8443** ^These interfaces are only available if SQLite is compiled using the 8444** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8445** 8446** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8447** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8448** on a database table. 8449** ^At most one preupdate hook may be registered at a time on a single 8450** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8451** the previous setting. 8452** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8453** with a NULL pointer as the second parameter. 8454** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8455** the first parameter to callbacks. 8456** 8457** ^The preupdate hook only fires for changes to real database tables; the 8458** preupdate hook is not invoked for changes to [virtual tables] or to 8459** system tables like sqlite_master or sqlite_stat1. 8460** 8461** ^The second parameter to the preupdate callback is a pointer to 8462** the [database connection] that registered the preupdate hook. 8463** ^The third parameter to the preupdate callback is one of the constants 8464** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8465** kind of update operation that is about to occur. 8466** ^(The fourth parameter to the preupdate callback is the name of the 8467** database within the database connection that is being modified. This 8468** will be "main" for the main database or "temp" for TEMP tables or 8469** the name given after the AS keyword in the [ATTACH] statement for attached 8470** databases.)^ 8471** ^The fifth parameter to the preupdate callback is the name of the 8472** table that is being modified. 8473** 8474** For an UPDATE or DELETE operation on a [rowid table], the sixth 8475** parameter passed to the preupdate callback is the initial [rowid] of the 8476** row being modified or deleted. For an INSERT operation on a rowid table, 8477** or any operation on a WITHOUT ROWID table, the value of the sixth 8478** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8479** seventh parameter is the final rowid value of the row being inserted 8480** or updated. The value of the seventh parameter passed to the callback 8481** function is not defined for operations on WITHOUT ROWID tables, or for 8482** INSERT operations on rowid tables. 8483** 8484** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8485** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8486** provide additional information about a preupdate event. These routines 8487** may only be called from within a preupdate callback. Invoking any of 8488** these routines from outside of a preupdate callback or with a 8489** [database connection] pointer that is different from the one supplied 8490** to the preupdate callback results in undefined and probably undesirable 8491** behavior. 8492** 8493** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8494** in the row that is being inserted, updated, or deleted. 8495** 8496** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8497** a [protected sqlite3_value] that contains the value of the Nth column of 8498** the table row before it is updated. The N parameter must be between 0 8499** and one less than the number of columns or the behavior will be 8500** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8501** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8502** behavior is undefined. The [sqlite3_value] that P points to 8503** will be destroyed when the preupdate callback returns. 8504** 8505** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8506** a [protected sqlite3_value] that contains the value of the Nth column of 8507** the table row after it is updated. The N parameter must be between 0 8508** and one less than the number of columns or the behavior will be 8509** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8510** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8511** behavior is undefined. The [sqlite3_value] that P points to 8512** will be destroyed when the preupdate callback returns. 8513** 8514** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8515** callback was invoked as a result of a direct insert, update, or delete 8516** operation; or 1 for inserts, updates, or deletes invoked by top-level 8517** triggers; or 2 for changes resulting from triggers called by top-level 8518** triggers; and so forth. 8519** 8520** See also: [sqlite3_update_hook()] 8521*/ 8522#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8523void *sqlite3_preupdate_hook( 8524 sqlite3 *db, 8525 void(*xPreUpdate)( 8526 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8527 sqlite3 *db, /* Database handle */ 8528 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8529 char const *zDb, /* Database name */ 8530 char const *zName, /* Table name */ 8531 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8532 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8533 ), 8534 void* 8535); 8536int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8537int sqlite3_preupdate_count(sqlite3 *); 8538int sqlite3_preupdate_depth(sqlite3 *); 8539int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8540#endif 8541 8542/* 8543** CAPI3REF: Low-level system error code 8544** 8545** ^Attempt to return the underlying operating system error code or error 8546** number that caused the most recent I/O error or failure to open a file. 8547** The return value is OS-dependent. For example, on unix systems, after 8548** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8549** called to get back the underlying "errno" that caused the problem, such 8550** as ENOSPC, EAUTH, EISDIR, and so forth. 8551*/ 8552int sqlite3_system_errno(sqlite3*); 8553 8554/* 8555** CAPI3REF: Database Snapshot 8556** KEYWORDS: {snapshot} {sqlite3_snapshot} 8557** EXPERIMENTAL 8558** 8559** An instance of the snapshot object records the state of a [WAL mode] 8560** database for some specific point in history. 8561** 8562** In [WAL mode], multiple [database connections] that are open on the 8563** same database file can each be reading a different historical version 8564** of the database file. When a [database connection] begins a read 8565** transaction, that connection sees an unchanging copy of the database 8566** as it existed for the point in time when the transaction first started. 8567** Subsequent changes to the database from other connections are not seen 8568** by the reader until a new read transaction is started. 8569** 8570** The sqlite3_snapshot object records state information about an historical 8571** version of the database file so that it is possible to later open a new read 8572** transaction that sees that historical version of the database rather than 8573** the most recent version. 8574** 8575** The constructor for this object is [sqlite3_snapshot_get()]. The 8576** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8577** to an historical snapshot (if possible). The destructor for 8578** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8579*/ 8580typedef struct sqlite3_snapshot { 8581 unsigned char hidden[48]; 8582} sqlite3_snapshot; 8583 8584/* 8585** CAPI3REF: Record A Database Snapshot 8586** EXPERIMENTAL 8587** 8588** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8589** new [sqlite3_snapshot] object that records the current state of 8590** schema S in database connection D. ^On success, the 8591** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8592** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8593** If there is not already a read-transaction open on schema S when 8594** this function is called, one is opened automatically. 8595** 8596** The following must be true for this function to succeed. If any of 8597** the following statements are false when sqlite3_snapshot_get() is 8598** called, SQLITE_ERROR is returned. The final value of *P is undefined 8599** in this case. 8600** 8601** <ul> 8602** <li> The database handle must be in [autocommit mode]. 8603** 8604** <li> Schema S of [database connection] D must be a [WAL mode] database. 8605** 8606** <li> There must not be a write transaction open on schema S of database 8607** connection D. 8608** 8609** <li> One or more transactions must have been written to the current wal 8610** file since it was created on disk (by any connection). This means 8611** that a snapshot cannot be taken on a wal mode database with no wal 8612** file immediately after it is first opened. At least one transaction 8613** must be written to it first. 8614** </ul> 8615** 8616** This function may also return SQLITE_NOMEM. If it is called with the 8617** database handle in autocommit mode but fails for some other reason, 8618** whether or not a read transaction is opened on schema S is undefined. 8619** 8620** The [sqlite3_snapshot] object returned from a successful call to 8621** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8622** to avoid a memory leak. 8623** 8624** The [sqlite3_snapshot_get()] interface is only available when the 8625** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8626*/ 8627SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8628 sqlite3 *db, 8629 const char *zSchema, 8630 sqlite3_snapshot **ppSnapshot 8631); 8632 8633/* 8634** CAPI3REF: Start a read transaction on an historical snapshot 8635** EXPERIMENTAL 8636** 8637** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8638** read transaction for schema S of 8639** [database connection] D such that the read transaction 8640** refers to historical [snapshot] P, rather than the most 8641** recent change to the database. 8642** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8643** or an appropriate [error code] if it fails. 8644** 8645** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8646** the first operation following the [BEGIN] that takes the schema S 8647** out of [autocommit mode]. 8648** ^In other words, schema S must not currently be in 8649** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8650** database connection D must be out of [autocommit mode]. 8651** ^A [snapshot] will fail to open if it has been overwritten by a 8652** [checkpoint]. 8653** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8654** database connection D does not know that the database file for 8655** schema S is in [WAL mode]. A database connection might not know 8656** that the database file is in [WAL mode] if there has been no prior 8657** I/O on that database connection, or if the database entered [WAL mode] 8658** after the most recent I/O on the database connection.)^ 8659** (Hint: Run "[PRAGMA application_id]" against a newly opened 8660** database connection in order to make it ready to use snapshots.) 8661** 8662** The [sqlite3_snapshot_open()] interface is only available when the 8663** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8664*/ 8665SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8666 sqlite3 *db, 8667 const char *zSchema, 8668 sqlite3_snapshot *pSnapshot 8669); 8670 8671/* 8672** CAPI3REF: Destroy a snapshot 8673** EXPERIMENTAL 8674** 8675** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8676** The application must eventually free every [sqlite3_snapshot] object 8677** using this routine to avoid a memory leak. 8678** 8679** The [sqlite3_snapshot_free()] interface is only available when the 8680** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8681*/ 8682SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8683 8684/* 8685** CAPI3REF: Compare the ages of two snapshot handles. 8686** EXPERIMENTAL 8687** 8688** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8689** of two valid snapshot handles. 8690** 8691** If the two snapshot handles are not associated with the same database 8692** file, the result of the comparison is undefined. 8693** 8694** Additionally, the result of the comparison is only valid if both of the 8695** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8696** last time the wal file was deleted. The wal file is deleted when the 8697** database is changed back to rollback mode or when the number of database 8698** clients drops to zero. If either snapshot handle was obtained before the 8699** wal file was last deleted, the value returned by this function 8700** is undefined. 8701** 8702** Otherwise, this API returns a negative value if P1 refers to an older 8703** snapshot than P2, zero if the two handles refer to the same database 8704** snapshot, and a positive value if P1 is a newer snapshot than P2. 8705*/ 8706SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8707 sqlite3_snapshot *p1, 8708 sqlite3_snapshot *p2 8709); 8710 8711/* 8712** CAPI3REF: Recover snapshots from a wal file 8713** EXPERIMENTAL 8714** 8715** If all connections disconnect from a database file but do not perform 8716** a checkpoint, the existing wal file is opened along with the database 8717** file the next time the database is opened. At this point it is only 8718** possible to successfully call sqlite3_snapshot_open() to open the most 8719** recent snapshot of the database (the one at the head of the wal file), 8720** even though the wal file may contain other valid snapshots for which 8721** clients have sqlite3_snapshot handles. 8722** 8723** This function attempts to scan the wal file associated with database zDb 8724** of database handle db and make all valid snapshots available to 8725** sqlite3_snapshot_open(). It is an error if there is already a read 8726** transaction open on the database, or if the database is not a wal mode 8727** database. 8728** 8729** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8730*/ 8731SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8732 8733/* 8734** Undo the hack that converts floating point types to integer for 8735** builds on processors without floating point support. 8736*/ 8737#ifdef SQLITE_OMIT_FLOATING_POINT 8738# undef double 8739#endif 8740 8741#ifdef __cplusplus 8742} /* End of the 'extern "C"' block */ 8743#endif 8744#endif /* SQLITE3_H */ 8745