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_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 474#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 506#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 507#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 508#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 509#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 510#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 511#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 512#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 513#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) 514#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 515#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 516#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 517#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 518#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 519#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 520#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 521#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 522#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 523#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 524#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 525#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 526#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 527#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 528#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 529#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 530#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 531#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 532#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 533#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 534#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 535#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 536#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 537 538/* 539** CAPI3REF: Flags For File Open Operations 540** 541** These bit values are intended for use in the 542** 3rd parameter to the [sqlite3_open_v2()] interface and 543** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 544*/ 545#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 546#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 547#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 548#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 549#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 550#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 551#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 552#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 553#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 554#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 555#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 556#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 557#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 558#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 559#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 560#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 562#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 563#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 564#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 565 566/* Reserved: 0x00F00000 */ 567 568/* 569** CAPI3REF: Device Characteristics 570** 571** The xDeviceCharacteristics method of the [sqlite3_io_methods] 572** object returns an integer which is a vector of these 573** bit values expressing I/O characteristics of the mass storage 574** device that holds the file that the [sqlite3_io_methods] 575** refers to. 576** 577** The SQLITE_IOCAP_ATOMIC property means that all writes of 578** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 579** mean that writes of blocks that are nnn bytes in size and 580** are aligned to an address which is an integer multiple of 581** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 582** that when data is appended to a file, the data is appended 583** first then the size of the file is extended, never the other 584** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 585** information is written to disk in the same order as calls 586** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 587** after reboot following a crash or power loss, the only bytes in a 588** file that were written at the application level might have changed 589** and that adjacent bytes, even bytes within the same sector are 590** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 591** flag indicates that a file cannot be deleted when open. The 592** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 593** read-only media and cannot be changed even by processes with 594** elevated privileges. 595** 596** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 597** filesystem supports doing multiple write operations atomically when those 598** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 599** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 600*/ 601#define SQLITE_IOCAP_ATOMIC 0x00000001 602#define SQLITE_IOCAP_ATOMIC512 0x00000002 603#define SQLITE_IOCAP_ATOMIC1K 0x00000004 604#define SQLITE_IOCAP_ATOMIC2K 0x00000008 605#define SQLITE_IOCAP_ATOMIC4K 0x00000010 606#define SQLITE_IOCAP_ATOMIC8K 0x00000020 607#define SQLITE_IOCAP_ATOMIC16K 0x00000040 608#define SQLITE_IOCAP_ATOMIC32K 0x00000080 609#define SQLITE_IOCAP_ATOMIC64K 0x00000100 610#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 611#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 612#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 613#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 614#define SQLITE_IOCAP_IMMUTABLE 0x00002000 615#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 616 617/* 618** CAPI3REF: File Locking Levels 619** 620** SQLite uses one of these integer values as the second 621** argument to calls it makes to the xLock() and xUnlock() methods 622** of an [sqlite3_io_methods] object. 623*/ 624#define SQLITE_LOCK_NONE 0 625#define SQLITE_LOCK_SHARED 1 626#define SQLITE_LOCK_RESERVED 2 627#define SQLITE_LOCK_PENDING 3 628#define SQLITE_LOCK_EXCLUSIVE 4 629 630/* 631** CAPI3REF: Synchronization Type Flags 632** 633** When SQLite invokes the xSync() method of an 634** [sqlite3_io_methods] object it uses a combination of 635** these integer values as the second argument. 636** 637** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 638** sync operation only needs to flush data to mass storage. Inode 639** information need not be flushed. If the lower four bits of the flag 640** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 641** If the lower four bits equal SQLITE_SYNC_FULL, that means 642** to use Mac OS X style fullsync instead of fsync(). 643** 644** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 645** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 646** settings. The [synchronous pragma] determines when calls to the 647** xSync VFS method occur and applies uniformly across all platforms. 648** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 649** energetic or rigorous or forceful the sync operations are and 650** only make a difference on Mac OSX for the default SQLite code. 651** (Third-party VFS implementations might also make the distinction 652** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 653** operating systems natively supported by SQLite, only Mac OSX 654** cares about the difference.) 655*/ 656#define SQLITE_SYNC_NORMAL 0x00002 657#define SQLITE_SYNC_FULL 0x00003 658#define SQLITE_SYNC_DATAONLY 0x00010 659 660/* 661** CAPI3REF: OS Interface Open File Handle 662** 663** An [sqlite3_file] object represents an open file in the 664** [sqlite3_vfs | OS interface layer]. Individual OS interface 665** implementations will 666** want to subclass this object by appending additional fields 667** for their own use. The pMethods entry is a pointer to an 668** [sqlite3_io_methods] object that defines methods for performing 669** I/O operations on the open file. 670*/ 671typedef struct sqlite3_file sqlite3_file; 672struct sqlite3_file { 673 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 674}; 675 676/* 677** CAPI3REF: OS Interface File Virtual Methods Object 678** 679** Every file opened by the [sqlite3_vfs.xOpen] method populates an 680** [sqlite3_file] object (or, more commonly, a subclass of the 681** [sqlite3_file] object) with a pointer to an instance of this object. 682** This object defines the methods used to perform various operations 683** against the open file represented by the [sqlite3_file] object. 684** 685** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 686** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 687** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 688** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 689** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 690** to NULL. 691** 692** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 693** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 694** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 695** flag may be ORed in to indicate that only the data of the file 696** and not its inode needs to be synced. 697** 698** The integer values to xLock() and xUnlock() are one of 699** <ul> 700** <li> [SQLITE_LOCK_NONE], 701** <li> [SQLITE_LOCK_SHARED], 702** <li> [SQLITE_LOCK_RESERVED], 703** <li> [SQLITE_LOCK_PENDING], or 704** <li> [SQLITE_LOCK_EXCLUSIVE]. 705** </ul> 706** xLock() increases the lock. xUnlock() decreases the lock. 707** The xCheckReservedLock() method checks whether any database connection, 708** either in this process or in some other process, is holding a RESERVED, 709** PENDING, or EXCLUSIVE lock on the file. It returns true 710** if such a lock exists and false otherwise. 711** 712** The xFileControl() method is a generic interface that allows custom 713** VFS implementations to directly control an open file using the 714** [sqlite3_file_control()] interface. The second "op" argument is an 715** integer opcode. The third argument is a generic pointer intended to 716** point to a structure that may contain arguments or space in which to 717** write return values. Potential uses for xFileControl() might be 718** functions to enable blocking locks with timeouts, to change the 719** locking strategy (for example to use dot-file locks), to inquire 720** about the status of a lock, or to break stale locks. The SQLite 721** core reserves all opcodes less than 100 for its own use. 722** A [file control opcodes | list of opcodes] less than 100 is available. 723** Applications that define a custom xFileControl method should use opcodes 724** greater than 100 to avoid conflicts. VFS implementations should 725** return [SQLITE_NOTFOUND] for file control opcodes that they do not 726** recognize. 727** 728** The xSectorSize() method returns the sector size of the 729** device that underlies the file. The sector size is the 730** minimum write that can be performed without disturbing 731** other bytes in the file. The xDeviceCharacteristics() 732** method returns a bit vector describing behaviors of the 733** underlying device: 734** 735** <ul> 736** <li> [SQLITE_IOCAP_ATOMIC] 737** <li> [SQLITE_IOCAP_ATOMIC512] 738** <li> [SQLITE_IOCAP_ATOMIC1K] 739** <li> [SQLITE_IOCAP_ATOMIC2K] 740** <li> [SQLITE_IOCAP_ATOMIC4K] 741** <li> [SQLITE_IOCAP_ATOMIC8K] 742** <li> [SQLITE_IOCAP_ATOMIC16K] 743** <li> [SQLITE_IOCAP_ATOMIC32K] 744** <li> [SQLITE_IOCAP_ATOMIC64K] 745** <li> [SQLITE_IOCAP_SAFE_APPEND] 746** <li> [SQLITE_IOCAP_SEQUENTIAL] 747** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 748** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 749** <li> [SQLITE_IOCAP_IMMUTABLE] 750** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 751** </ul> 752** 753** The SQLITE_IOCAP_ATOMIC property means that all writes of 754** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 755** mean that writes of blocks that are nnn bytes in size and 756** are aligned to an address which is an integer multiple of 757** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 758** that when data is appended to a file, the data is appended 759** first then the size of the file is extended, never the other 760** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 761** information is written to disk in the same order as calls 762** to xWrite(). 763** 764** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 765** in the unread portions of the buffer with zeros. A VFS that 766** fails to zero-fill short reads might seem to work. However, 767** failure to zero-fill short reads will eventually lead to 768** database corruption. 769*/ 770typedef struct sqlite3_io_methods sqlite3_io_methods; 771struct sqlite3_io_methods { 772 int iVersion; 773 int (*xClose)(sqlite3_file*); 774 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 775 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 776 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 777 int (*xSync)(sqlite3_file*, int flags); 778 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 779 int (*xLock)(sqlite3_file*, int); 780 int (*xUnlock)(sqlite3_file*, int); 781 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 782 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 783 int (*xSectorSize)(sqlite3_file*); 784 int (*xDeviceCharacteristics)(sqlite3_file*); 785 /* Methods above are valid for version 1 */ 786 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 787 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 788 void (*xShmBarrier)(sqlite3_file*); 789 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 790 /* Methods above are valid for version 2 */ 791 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 792 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 793 /* Methods above are valid for version 3 */ 794 /* Additional methods may be added in future releases */ 795}; 796 797/* 798** CAPI3REF: Standard File Control Opcodes 799** KEYWORDS: {file control opcodes} {file control opcode} 800** 801** These integer constants are opcodes for the xFileControl method 802** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 803** interface. 804** 805** <ul> 806** <li>[[SQLITE_FCNTL_LOCKSTATE]] 807** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 808** opcode causes the xFileControl method to write the current state of 809** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 810** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 811** into an integer that the pArg argument points to. This capability 812** is used during testing and is only available when the SQLITE_TEST 813** compile-time option is used. 814** 815** <li>[[SQLITE_FCNTL_SIZE_HINT]] 816** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 817** layer a hint of how large the database file will grow to be during the 818** current transaction. This hint is not guaranteed to be accurate but it 819** is often close. The underlying VFS might choose to preallocate database 820** file space based on this hint in order to help writes to the database 821** file run faster. 822** 823** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 824** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 825** extends and truncates the database file in chunks of a size specified 826** by the user. The fourth argument to [sqlite3_file_control()] should 827** point to an integer (type int) containing the new chunk-size to use 828** for the nominated database. Allocating database file space in large 829** chunks (say 1MB at a time), may reduce file-system fragmentation and 830** improve performance on some systems. 831** 832** <li>[[SQLITE_FCNTL_FILE_POINTER]] 833** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 834** to the [sqlite3_file] object associated with a particular database 835** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 836** 837** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 838** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 839** to the [sqlite3_file] object associated with the journal file (either 840** the [rollback journal] or the [write-ahead log]) for a particular database 841** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 842** 843** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 844** No longer in use. 845** 846** <li>[[SQLITE_FCNTL_SYNC]] 847** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 848** sent to the VFS immediately before the xSync method is invoked on a 849** database file descriptor. Or, if the xSync method is not invoked 850** because the user has configured SQLite with 851** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 852** of the xSync method. In most cases, the pointer argument passed with 853** this file-control is NULL. However, if the database file is being synced 854** as part of a multi-database commit, the argument points to a nul-terminated 855** string containing the transactions master-journal file name. VFSes that 856** do not need this signal should silently ignore this opcode. Applications 857** should not call [sqlite3_file_control()] with this opcode as doing so may 858** disrupt the operation of the specialized VFSes that do require it. 859** 860** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 861** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 862** and sent to the VFS after a transaction has been committed immediately 863** but before the database is unlocked. VFSes that do not need this signal 864** should silently ignore this opcode. Applications should not call 865** [sqlite3_file_control()] with this opcode as doing so may disrupt the 866** operation of the specialized VFSes that do require it. 867** 868** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 869** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 870** retry counts and intervals for certain disk I/O operations for the 871** windows [VFS] in order to provide robustness in the presence of 872** anti-virus programs. By default, the windows VFS will retry file read, 873** file write, and file delete operations up to 10 times, with a delay 874** of 25 milliseconds before the first retry and with the delay increasing 875** by an additional 25 milliseconds with each subsequent retry. This 876** opcode allows these two values (10 retries and 25 milliseconds of delay) 877** to be adjusted. The values are changed for all database connections 878** within the same process. The argument is a pointer to an array of two 879** integers where the first integer is the new retry count and the second 880** integer is the delay. If either integer is negative, then the setting 881** is not changed but instead the prior value of that setting is written 882** into the array entry, allowing the current retry settings to be 883** interrogated. The zDbName parameter is ignored. 884** 885** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 886** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 887** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 888** write ahead log and shared memory files used for transaction control 889** are automatically deleted when the latest connection to the database 890** closes. Setting persistent WAL mode causes those files to persist after 891** close. Persisting the files is useful when other processes that do not 892** have write permission on the directory containing the database file want 893** to read the database file, as the WAL and shared memory files must exist 894** in order for the database to be readable. The fourth parameter to 895** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 896** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 897** WAL mode. If the integer is -1, then it is overwritten with the current 898** WAL persistence setting. 899** 900** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 901** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 902** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 903** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 904** xDeviceCharacteristics methods. The fourth parameter to 905** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 906** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 907** mode. If the integer is -1, then it is overwritten with the current 908** zero-damage mode setting. 909** 910** <li>[[SQLITE_FCNTL_OVERWRITE]] 911** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 912** a write transaction to indicate that, unless it is rolled back for some 913** reason, the entire database file will be overwritten by the current 914** transaction. This is used by VACUUM operations. 915** 916** <li>[[SQLITE_FCNTL_VFSNAME]] 917** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 918** all [VFSes] in the VFS stack. The names are of all VFS shims and the 919** final bottom-level VFS are written into memory obtained from 920** [sqlite3_malloc()] and the result is stored in the char* variable 921** that the fourth parameter of [sqlite3_file_control()] points to. 922** The caller is responsible for freeing the memory when done. As with 923** all file-control actions, there is no guarantee that this will actually 924** do anything. Callers should initialize the char* variable to a NULL 925** pointer in case this file-control is not implemented. This file-control 926** is intended for diagnostic use only. 927** 928** <li>[[SQLITE_FCNTL_VFS_POINTER]] 929** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 930** [VFSes] currently in use. ^(The argument X in 931** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 932** of type "[sqlite3_vfs] **". This opcodes will set *X 933** to a pointer to the top-level VFS.)^ 934** ^When there are multiple VFS shims in the stack, this opcode finds the 935** upper-most shim only. 936** 937** <li>[[SQLITE_FCNTL_PRAGMA]] 938** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 939** file control is sent to the open [sqlite3_file] object corresponding 940** to the database file to which the pragma statement refers. ^The argument 941** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 942** pointers to strings (char**) in which the second element of the array 943** is the name of the pragma and the third element is the argument to the 944** pragma or NULL if the pragma has no argument. ^The handler for an 945** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 946** of the char** argument point to a string obtained from [sqlite3_mprintf()] 947** or the equivalent and that string will become the result of the pragma or 948** the error message if the pragma fails. ^If the 949** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 950** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 951** file control returns [SQLITE_OK], then the parser assumes that the 952** VFS has handled the PRAGMA itself and the parser generates a no-op 953** prepared statement if result string is NULL, or that returns a copy 954** of the result string if the string is non-NULL. 955** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 956** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 957** that the VFS encountered an error while handling the [PRAGMA] and the 958** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 959** file control occurs at the beginning of pragma statement analysis and so 960** it is able to override built-in [PRAGMA] statements. 961** 962** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 963** ^The [SQLITE_FCNTL_BUSYHANDLER] 964** file-control may be invoked by SQLite on the database file handle 965** shortly after it is opened in order to provide a custom VFS with access 966** to the connections busy-handler callback. The argument is of type (void **) 967** - an array of two (void *) values. The first (void *) actually points 968** to a function of type (int (*)(void *)). In order to invoke the connections 969** busy-handler, this function should be invoked with the second (void *) in 970** the array as the only argument. If it returns non-zero, then the operation 971** should be retried. If it returns zero, the custom VFS should abandon the 972** current operation. 973** 974** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 975** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 976** to have SQLite generate a 977** temporary filename using the same algorithm that is followed to generate 978** temporary filenames for TEMP tables and other internal uses. The 979** argument should be a char** which will be filled with the filename 980** written into memory obtained from [sqlite3_malloc()]. The caller should 981** invoke [sqlite3_free()] on the result to avoid a memory leak. 982** 983** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 984** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 985** maximum number of bytes that will be used for memory-mapped I/O. 986** The argument is a pointer to a value of type sqlite3_int64 that 987** is an advisory maximum number of bytes in the file to memory map. The 988** pointer is overwritten with the old value. The limit is not changed if 989** the value originally pointed to is negative, and so the current limit 990** can be queried by passing in a pointer to a negative number. This 991** file-control is used internally to implement [PRAGMA mmap_size]. 992** 993** <li>[[SQLITE_FCNTL_TRACE]] 994** The [SQLITE_FCNTL_TRACE] file control provides advisory information 995** to the VFS about what the higher layers of the SQLite stack are doing. 996** This file control is used by some VFS activity tracing [shims]. 997** The argument is a zero-terminated string. Higher layers in the 998** SQLite stack may generate instances of this file control if 999** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1000** 1001** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1002** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1003** pointer to an integer and it writes a boolean into that integer depending 1004** on whether or not the file has been renamed, moved, or deleted since it 1005** was first opened. 1006** 1007** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1008** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1009** underlying native file handle associated with a file handle. This file 1010** control interprets its argument as a pointer to a native file handle and 1011** writes the resulting value there. 1012** 1013** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1014** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1015** opcode causes the xFileControl method to swap the file handle with the one 1016** pointed to by the pArg argument. This capability is used during testing 1017** and only needs to be supported when SQLITE_TEST is defined. 1018** 1019** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1020** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1021** be advantageous to block on the next WAL lock if the lock is not immediately 1022** available. The WAL subsystem issues this signal during rare 1023** circumstances in order to fix a problem with priority inversion. 1024** Applications should <em>not</em> use this file-control. 1025** 1026** <li>[[SQLITE_FCNTL_ZIPVFS]] 1027** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1028** VFS should return SQLITE_NOTFOUND for this opcode. 1029** 1030** <li>[[SQLITE_FCNTL_RBU]] 1031** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1032** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1033** this opcode. 1034** 1035** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1036** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1037** the file descriptor is placed in "batch write mode", which 1038** means all subsequent write operations will be deferred and done 1039** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1040** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1041** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1042** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1043** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1044** no VFS interface calls on the same [sqlite3_file] file descriptor 1045** except for calls to the xWrite method and the xFileControl method 1046** with [SQLITE_FCNTL_SIZE_HINT]. 1047** 1048** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1049** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1050** operations since the previous successful call to 1051** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1052** This file control returns [SQLITE_OK] if and only if the writes were 1053** all performed successfully and have been committed to persistent storage. 1054** ^Regardless of whether or not it is successful, this file control takes 1055** the file descriptor out of batch write mode so that all subsequent 1056** write operations are independent. 1057** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1058** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1059** 1060** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1061** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1062** operations since the previous successful call to 1063** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1064** ^This file control takes the file descriptor out of batch write mode 1065** so that all subsequent write operations are independent. 1066** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1067** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1068** </ul> 1069*/ 1070#define SQLITE_FCNTL_LOCKSTATE 1 1071#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1072#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1073#define SQLITE_FCNTL_LAST_ERRNO 4 1074#define SQLITE_FCNTL_SIZE_HINT 5 1075#define SQLITE_FCNTL_CHUNK_SIZE 6 1076#define SQLITE_FCNTL_FILE_POINTER 7 1077#define SQLITE_FCNTL_SYNC_OMITTED 8 1078#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1079#define SQLITE_FCNTL_PERSIST_WAL 10 1080#define SQLITE_FCNTL_OVERWRITE 11 1081#define SQLITE_FCNTL_VFSNAME 12 1082#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1083#define SQLITE_FCNTL_PRAGMA 14 1084#define SQLITE_FCNTL_BUSYHANDLER 15 1085#define SQLITE_FCNTL_TEMPFILENAME 16 1086#define SQLITE_FCNTL_MMAP_SIZE 18 1087#define SQLITE_FCNTL_TRACE 19 1088#define SQLITE_FCNTL_HAS_MOVED 20 1089#define SQLITE_FCNTL_SYNC 21 1090#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1091#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1092#define SQLITE_FCNTL_WAL_BLOCK 24 1093#define SQLITE_FCNTL_ZIPVFS 25 1094#define SQLITE_FCNTL_RBU 26 1095#define SQLITE_FCNTL_VFS_POINTER 27 1096#define SQLITE_FCNTL_JOURNAL_POINTER 28 1097#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1098#define SQLITE_FCNTL_PDB 30 1099#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1100#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1101#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1102 1103/* deprecated names */ 1104#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1105#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1106#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1107 1108 1109/* 1110** CAPI3REF: Mutex Handle 1111** 1112** The mutex module within SQLite defines [sqlite3_mutex] to be an 1113** abstract type for a mutex object. The SQLite core never looks 1114** at the internal representation of an [sqlite3_mutex]. It only 1115** deals with pointers to the [sqlite3_mutex] object. 1116** 1117** Mutexes are created using [sqlite3_mutex_alloc()]. 1118*/ 1119typedef struct sqlite3_mutex sqlite3_mutex; 1120 1121/* 1122** CAPI3REF: Loadable Extension Thunk 1123** 1124** A pointer to the opaque sqlite3_api_routines structure is passed as 1125** the third parameter to entry points of [loadable extensions]. This 1126** structure must be typedefed in order to work around compiler warnings 1127** on some platforms. 1128*/ 1129typedef struct sqlite3_api_routines sqlite3_api_routines; 1130 1131/* 1132** CAPI3REF: OS Interface Object 1133** 1134** An instance of the sqlite3_vfs object defines the interface between 1135** the SQLite core and the underlying operating system. The "vfs" 1136** in the name of the object stands for "virtual file system". See 1137** the [VFS | VFS documentation] for further information. 1138** 1139** The VFS interface is sometimes extended by adding new methods onto 1140** the end. Each time such an extension occurs, the iVersion field 1141** is incremented. The iVersion value started out as 1 in 1142** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1143** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1144** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1145** may be appended to the sqlite3_vfs object and the iVersion value 1146** may increase again in future versions of SQLite. 1147** Note that the structure 1148** of the sqlite3_vfs object changes in the transition from 1149** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1150** and yet the iVersion field was not modified. 1151** 1152** The szOsFile field is the size of the subclassed [sqlite3_file] 1153** structure used by this VFS. mxPathname is the maximum length of 1154** a pathname in this VFS. 1155** 1156** Registered sqlite3_vfs objects are kept on a linked list formed by 1157** the pNext pointer. The [sqlite3_vfs_register()] 1158** and [sqlite3_vfs_unregister()] interfaces manage this list 1159** in a thread-safe way. The [sqlite3_vfs_find()] interface 1160** searches the list. Neither the application code nor the VFS 1161** implementation should use the pNext pointer. 1162** 1163** The pNext field is the only field in the sqlite3_vfs 1164** structure that SQLite will ever modify. SQLite will only access 1165** or modify this field while holding a particular static mutex. 1166** The application should never modify anything within the sqlite3_vfs 1167** object once the object has been registered. 1168** 1169** The zName field holds the name of the VFS module. The name must 1170** be unique across all VFS modules. 1171** 1172** [[sqlite3_vfs.xOpen]] 1173** ^SQLite guarantees that the zFilename parameter to xOpen 1174** is either a NULL pointer or string obtained 1175** from xFullPathname() with an optional suffix added. 1176** ^If a suffix is added to the zFilename parameter, it will 1177** consist of a single "-" character followed by no more than 1178** 11 alphanumeric and/or "-" characters. 1179** ^SQLite further guarantees that 1180** the string will be valid and unchanged until xClose() is 1181** called. Because of the previous sentence, 1182** the [sqlite3_file] can safely store a pointer to the 1183** filename if it needs to remember the filename for some reason. 1184** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1185** must invent its own temporary name for the file. ^Whenever the 1186** xFilename parameter is NULL it will also be the case that the 1187** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1188** 1189** The flags argument to xOpen() includes all bits set in 1190** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1191** or [sqlite3_open16()] is used, then flags includes at least 1192** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1193** If xOpen() opens a file read-only then it sets *pOutFlags to 1194** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1195** 1196** ^(SQLite will also add one of the following flags to the xOpen() 1197** call, depending on the object being opened: 1198** 1199** <ul> 1200** <li> [SQLITE_OPEN_MAIN_DB] 1201** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1202** <li> [SQLITE_OPEN_TEMP_DB] 1203** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1204** <li> [SQLITE_OPEN_TRANSIENT_DB] 1205** <li> [SQLITE_OPEN_SUBJOURNAL] 1206** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1207** <li> [SQLITE_OPEN_WAL] 1208** </ul>)^ 1209** 1210** The file I/O implementation can use the object type flags to 1211** change the way it deals with files. For example, an application 1212** that does not care about crash recovery or rollback might make 1213** the open of a journal file a no-op. Writes to this journal would 1214** also be no-ops, and any attempt to read the journal would return 1215** SQLITE_IOERR. Or the implementation might recognize that a database 1216** file will be doing page-aligned sector reads and writes in a random 1217** order and set up its I/O subsystem accordingly. 1218** 1219** SQLite might also add one of the following flags to the xOpen method: 1220** 1221** <ul> 1222** <li> [SQLITE_OPEN_DELETEONCLOSE] 1223** <li> [SQLITE_OPEN_EXCLUSIVE] 1224** </ul> 1225** 1226** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1227** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1228** will be set for TEMP databases and their journals, transient 1229** databases, and subjournals. 1230** 1231** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1232** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1233** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1234** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1235** SQLITE_OPEN_CREATE, is used to indicate that file should always 1236** be created, and that it is an error if it already exists. 1237** It is <i>not</i> used to indicate the file should be opened 1238** for exclusive access. 1239** 1240** ^At least szOsFile bytes of memory are allocated by SQLite 1241** to hold the [sqlite3_file] structure passed as the third 1242** argument to xOpen. The xOpen method does not have to 1243** allocate the structure; it should just fill it in. Note that 1244** the xOpen method must set the sqlite3_file.pMethods to either 1245** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1246** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1247** element will be valid after xOpen returns regardless of the success 1248** or failure of the xOpen call. 1249** 1250** [[sqlite3_vfs.xAccess]] 1251** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1252** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1253** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1254** to test whether a file is at least readable. The file can be a 1255** directory. 1256** 1257** ^SQLite will always allocate at least mxPathname+1 bytes for the 1258** output buffer xFullPathname. The exact size of the output buffer 1259** is also passed as a parameter to both methods. If the output buffer 1260** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1261** handled as a fatal error by SQLite, vfs implementations should endeavor 1262** to prevent this by setting mxPathname to a sufficiently large value. 1263** 1264** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1265** interfaces are not strictly a part of the filesystem, but they are 1266** included in the VFS structure for completeness. 1267** The xRandomness() function attempts to return nBytes bytes 1268** of good-quality randomness into zOut. The return value is 1269** the actual number of bytes of randomness obtained. 1270** The xSleep() method causes the calling thread to sleep for at 1271** least the number of microseconds given. ^The xCurrentTime() 1272** method returns a Julian Day Number for the current date and time as 1273** a floating point value. 1274** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1275** Day Number multiplied by 86400000 (the number of milliseconds in 1276** a 24-hour day). 1277** ^SQLite will use the xCurrentTimeInt64() method to get the current 1278** date and time if that method is available (if iVersion is 2 or 1279** greater and the function pointer is not NULL) and will fall back 1280** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1281** 1282** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1283** are not used by the SQLite core. These optional interfaces are provided 1284** by some VFSes to facilitate testing of the VFS code. By overriding 1285** system calls with functions under its control, a test program can 1286** simulate faults and error conditions that would otherwise be difficult 1287** or impossible to induce. The set of system calls that can be overridden 1288** varies from one VFS to another, and from one version of the same VFS to the 1289** next. Applications that use these interfaces must be prepared for any 1290** or all of these interfaces to be NULL or for their behavior to change 1291** from one release to the next. Applications must not attempt to access 1292** any of these methods if the iVersion of the VFS is less than 3. 1293*/ 1294typedef struct sqlite3_vfs sqlite3_vfs; 1295typedef void (*sqlite3_syscall_ptr)(void); 1296struct sqlite3_vfs { 1297 int iVersion; /* Structure version number (currently 3) */ 1298 int szOsFile; /* Size of subclassed sqlite3_file */ 1299 int mxPathname; /* Maximum file pathname length */ 1300 sqlite3_vfs *pNext; /* Next registered VFS */ 1301 const char *zName; /* Name of this virtual file system */ 1302 void *pAppData; /* Pointer to application-specific data */ 1303 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1304 int flags, int *pOutFlags); 1305 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1306 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1307 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1308 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1309 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1310 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1311 void (*xDlClose)(sqlite3_vfs*, void*); 1312 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1313 int (*xSleep)(sqlite3_vfs*, int microseconds); 1314 int (*xCurrentTime)(sqlite3_vfs*, double*); 1315 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1316 /* 1317 ** The methods above are in version 1 of the sqlite_vfs object 1318 ** definition. Those that follow are added in version 2 or later 1319 */ 1320 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1321 /* 1322 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1323 ** Those below are for version 3 and greater. 1324 */ 1325 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1326 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1327 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1328 /* 1329 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1330 ** New fields may be appended in future versions. The iVersion 1331 ** value will increment whenever this happens. 1332 */ 1333}; 1334 1335/* 1336** CAPI3REF: Flags for the xAccess VFS method 1337** 1338** These integer constants can be used as the third parameter to 1339** the xAccess method of an [sqlite3_vfs] object. They determine 1340** what kind of permissions the xAccess method is looking for. 1341** With SQLITE_ACCESS_EXISTS, the xAccess method 1342** simply checks whether the file exists. 1343** With SQLITE_ACCESS_READWRITE, the xAccess method 1344** checks whether the named directory is both readable and writable 1345** (in other words, if files can be added, removed, and renamed within 1346** the directory). 1347** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1348** [temp_store_directory pragma], though this could change in a future 1349** release of SQLite. 1350** With SQLITE_ACCESS_READ, the xAccess method 1351** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1352** currently unused, though it might be used in a future release of 1353** SQLite. 1354*/ 1355#define SQLITE_ACCESS_EXISTS 0 1356#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1357#define SQLITE_ACCESS_READ 2 /* Unused */ 1358 1359/* 1360** CAPI3REF: Flags for the xShmLock VFS method 1361** 1362** These integer constants define the various locking operations 1363** allowed by the xShmLock method of [sqlite3_io_methods]. The 1364** following are the only legal combinations of flags to the 1365** xShmLock method: 1366** 1367** <ul> 1368** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1369** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1370** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1371** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1372** </ul> 1373** 1374** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1375** was given on the corresponding lock. 1376** 1377** The xShmLock method can transition between unlocked and SHARED or 1378** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1379** and EXCLUSIVE. 1380*/ 1381#define SQLITE_SHM_UNLOCK 1 1382#define SQLITE_SHM_LOCK 2 1383#define SQLITE_SHM_SHARED 4 1384#define SQLITE_SHM_EXCLUSIVE 8 1385 1386/* 1387** CAPI3REF: Maximum xShmLock index 1388** 1389** The xShmLock method on [sqlite3_io_methods] may use values 1390** between 0 and this upper bound as its "offset" argument. 1391** The SQLite core will never attempt to acquire or release a 1392** lock outside of this range 1393*/ 1394#define SQLITE_SHM_NLOCK 8 1395 1396 1397/* 1398** CAPI3REF: Initialize The SQLite Library 1399** 1400** ^The sqlite3_initialize() routine initializes the 1401** SQLite library. ^The sqlite3_shutdown() routine 1402** deallocates any resources that were allocated by sqlite3_initialize(). 1403** These routines are designed to aid in process initialization and 1404** shutdown on embedded systems. Workstation applications using 1405** SQLite normally do not need to invoke either of these routines. 1406** 1407** A call to sqlite3_initialize() is an "effective" call if it is 1408** the first time sqlite3_initialize() is invoked during the lifetime of 1409** the process, or if it is the first time sqlite3_initialize() is invoked 1410** following a call to sqlite3_shutdown(). ^(Only an effective call 1411** of sqlite3_initialize() does any initialization. All other calls 1412** are harmless no-ops.)^ 1413** 1414** A call to sqlite3_shutdown() is an "effective" call if it is the first 1415** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1416** an effective call to sqlite3_shutdown() does any deinitialization. 1417** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1418** 1419** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1420** is not. The sqlite3_shutdown() interface must only be called from a 1421** single thread. All open [database connections] must be closed and all 1422** other SQLite resources must be deallocated prior to invoking 1423** sqlite3_shutdown(). 1424** 1425** Among other things, ^sqlite3_initialize() will invoke 1426** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1427** will invoke sqlite3_os_end(). 1428** 1429** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1430** ^If for some reason, sqlite3_initialize() is unable to initialize 1431** the library (perhaps it is unable to allocate a needed resource such 1432** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1433** 1434** ^The sqlite3_initialize() routine is called internally by many other 1435** SQLite interfaces so that an application usually does not need to 1436** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1437** calls sqlite3_initialize() so the SQLite library will be automatically 1438** initialized when [sqlite3_open()] is called if it has not be initialized 1439** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1440** compile-time option, then the automatic calls to sqlite3_initialize() 1441** are omitted and the application must call sqlite3_initialize() directly 1442** prior to using any other SQLite interface. For maximum portability, 1443** it is recommended that applications always invoke sqlite3_initialize() 1444** directly prior to using any other SQLite interface. Future releases 1445** of SQLite may require this. In other words, the behavior exhibited 1446** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1447** default behavior in some future release of SQLite. 1448** 1449** The sqlite3_os_init() routine does operating-system specific 1450** initialization of the SQLite library. The sqlite3_os_end() 1451** routine undoes the effect of sqlite3_os_init(). Typical tasks 1452** performed by these routines include allocation or deallocation 1453** of static resources, initialization of global variables, 1454** setting up a default [sqlite3_vfs] module, or setting up 1455** a default configuration using [sqlite3_config()]. 1456** 1457** The application should never invoke either sqlite3_os_init() 1458** or sqlite3_os_end() directly. The application should only invoke 1459** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1460** interface is called automatically by sqlite3_initialize() and 1461** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1462** implementations for sqlite3_os_init() and sqlite3_os_end() 1463** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1464** When [custom builds | built for other platforms] 1465** (using the [SQLITE_OS_OTHER=1] compile-time 1466** option) the application must supply a suitable implementation for 1467** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1468** implementation of sqlite3_os_init() or sqlite3_os_end() 1469** must return [SQLITE_OK] on success and some other [error code] upon 1470** failure. 1471*/ 1472int sqlite3_initialize(void); 1473int sqlite3_shutdown(void); 1474int sqlite3_os_init(void); 1475int sqlite3_os_end(void); 1476 1477/* 1478** CAPI3REF: Configuring The SQLite Library 1479** 1480** The sqlite3_config() interface is used to make global configuration 1481** changes to SQLite in order to tune SQLite to the specific needs of 1482** the application. The default configuration is recommended for most 1483** applications and so this routine is usually not necessary. It is 1484** provided to support rare applications with unusual needs. 1485** 1486** <b>The sqlite3_config() interface is not threadsafe. The application 1487** must ensure that no other SQLite interfaces are invoked by other 1488** threads while sqlite3_config() is running.</b> 1489** 1490** The sqlite3_config() interface 1491** may only be invoked prior to library initialization using 1492** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1493** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1494** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1495** Note, however, that ^sqlite3_config() can be called as part of the 1496** implementation of an application-defined [sqlite3_os_init()]. 1497** 1498** The first argument to sqlite3_config() is an integer 1499** [configuration option] that determines 1500** what property of SQLite is to be configured. Subsequent arguments 1501** vary depending on the [configuration option] 1502** in the first argument. 1503** 1504** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1505** ^If the option is unknown or SQLite is unable to set the option 1506** then this routine returns a non-zero [error code]. 1507*/ 1508int sqlite3_config(int, ...); 1509 1510/* 1511** CAPI3REF: Configure database connections 1512** METHOD: sqlite3 1513** 1514** The sqlite3_db_config() interface is used to make configuration 1515** changes to a [database connection]. The interface is similar to 1516** [sqlite3_config()] except that the changes apply to a single 1517** [database connection] (specified in the first argument). 1518** 1519** The second argument to sqlite3_db_config(D,V,...) is the 1520** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1521** that indicates what aspect of the [database connection] is being configured. 1522** Subsequent arguments vary depending on the configuration verb. 1523** 1524** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1525** the call is considered successful. 1526*/ 1527int sqlite3_db_config(sqlite3*, int op, ...); 1528 1529/* 1530** CAPI3REF: Memory Allocation Routines 1531** 1532** An instance of this object defines the interface between SQLite 1533** and low-level memory allocation routines. 1534** 1535** This object is used in only one place in the SQLite interface. 1536** A pointer to an instance of this object is the argument to 1537** [sqlite3_config()] when the configuration option is 1538** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1539** By creating an instance of this object 1540** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1541** during configuration, an application can specify an alternative 1542** memory allocation subsystem for SQLite to use for all of its 1543** dynamic memory needs. 1544** 1545** Note that SQLite comes with several [built-in memory allocators] 1546** that are perfectly adequate for the overwhelming majority of applications 1547** and that this object is only useful to a tiny minority of applications 1548** with specialized memory allocation requirements. This object is 1549** also used during testing of SQLite in order to specify an alternative 1550** memory allocator that simulates memory out-of-memory conditions in 1551** order to verify that SQLite recovers gracefully from such 1552** conditions. 1553** 1554** The xMalloc, xRealloc, and xFree methods must work like the 1555** malloc(), realloc() and free() functions from the standard C library. 1556** ^SQLite guarantees that the second argument to 1557** xRealloc is always a value returned by a prior call to xRoundup. 1558** 1559** xSize should return the allocated size of a memory allocation 1560** previously obtained from xMalloc or xRealloc. The allocated size 1561** is always at least as big as the requested size but may be larger. 1562** 1563** The xRoundup method returns what would be the allocated size of 1564** a memory allocation given a particular requested size. Most memory 1565** allocators round up memory allocations at least to the next multiple 1566** of 8. Some allocators round up to a larger multiple or to a power of 2. 1567** Every memory allocation request coming in through [sqlite3_malloc()] 1568** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1569** that causes the corresponding memory allocation to fail. 1570** 1571** The xInit method initializes the memory allocator. For example, 1572** it might allocate any require mutexes or initialize internal data 1573** structures. The xShutdown method is invoked (indirectly) by 1574** [sqlite3_shutdown()] and should deallocate any resources acquired 1575** by xInit. The pAppData pointer is used as the only parameter to 1576** xInit and xShutdown. 1577** 1578** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1579** the xInit method, so the xInit method need not be threadsafe. The 1580** xShutdown method is only called from [sqlite3_shutdown()] so it does 1581** not need to be threadsafe either. For all other methods, SQLite 1582** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1583** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1584** it is by default) and so the methods are automatically serialized. 1585** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1586** methods must be threadsafe or else make their own arrangements for 1587** serialization. 1588** 1589** SQLite will never invoke xInit() more than once without an intervening 1590** call to xShutdown(). 1591*/ 1592typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1593struct sqlite3_mem_methods { 1594 void *(*xMalloc)(int); /* Memory allocation function */ 1595 void (*xFree)(void*); /* Free a prior allocation */ 1596 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1597 int (*xSize)(void*); /* Return the size of an allocation */ 1598 int (*xRoundup)(int); /* Round up request size to allocation size */ 1599 int (*xInit)(void*); /* Initialize the memory allocator */ 1600 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1601 void *pAppData; /* Argument to xInit() and xShutdown() */ 1602}; 1603 1604/* 1605** CAPI3REF: Configuration Options 1606** KEYWORDS: {configuration option} 1607** 1608** These constants are the available integer configuration options that 1609** can be passed as the first argument to the [sqlite3_config()] interface. 1610** 1611** New configuration options may be added in future releases of SQLite. 1612** Existing configuration options might be discontinued. Applications 1613** should check the return code from [sqlite3_config()] to make sure that 1614** the call worked. The [sqlite3_config()] interface will return a 1615** non-zero [error code] if a discontinued or unsupported configuration option 1616** is invoked. 1617** 1618** <dl> 1619** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1620** <dd>There are no arguments to this option. ^This option sets the 1621** [threading mode] to Single-thread. In other words, it disables 1622** all mutexing and puts SQLite into a mode where it can only be used 1623** by a single thread. ^If SQLite is compiled with 1624** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1625** it is not possible to change the [threading mode] from its default 1626** value of Single-thread and so [sqlite3_config()] will return 1627** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1628** configuration option.</dd> 1629** 1630** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1631** <dd>There are no arguments to this option. ^This option sets the 1632** [threading mode] to Multi-thread. In other words, it disables 1633** mutexing on [database connection] and [prepared statement] objects. 1634** The application is responsible for serializing access to 1635** [database connections] and [prepared statements]. But other mutexes 1636** are enabled so that SQLite will be safe to use in a multi-threaded 1637** environment as long as no two threads attempt to use the same 1638** [database connection] at the same time. ^If SQLite is compiled with 1639** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1640** it is not possible to set the Multi-thread [threading mode] and 1641** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1642** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1643** 1644** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1645** <dd>There are no arguments to this option. ^This option sets the 1646** [threading mode] to Serialized. In other words, this option enables 1647** all mutexes including the recursive 1648** mutexes on [database connection] and [prepared statement] objects. 1649** In this mode (which is the default when SQLite is compiled with 1650** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1651** to [database connections] and [prepared statements] so that the 1652** application is free to use the same [database connection] or the 1653** same [prepared statement] in different threads at the same time. 1654** ^If SQLite is compiled with 1655** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1656** it is not possible to set the Serialized [threading mode] and 1657** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1658** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1659** 1660** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1661** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1662** a pointer to an instance of the [sqlite3_mem_methods] structure. 1663** The argument specifies 1664** alternative low-level memory allocation routines to be used in place of 1665** the memory allocation routines built into SQLite.)^ ^SQLite makes 1666** its own private copy of the content of the [sqlite3_mem_methods] structure 1667** before the [sqlite3_config()] call returns.</dd> 1668** 1669** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1670** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1671** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1672** The [sqlite3_mem_methods] 1673** structure is filled with the currently defined memory allocation routines.)^ 1674** This option can be used to overload the default memory allocation 1675** routines with a wrapper that simulations memory allocation failure or 1676** tracks memory usage, for example. </dd> 1677** 1678** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1679** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1680** type int, interpreted as a boolean, which if true provides a hint to 1681** SQLite that it should avoid large memory allocations if possible. 1682** SQLite will run faster if it is free to make large memory allocations, 1683** but some application might prefer to run slower in exchange for 1684** guarantees about memory fragmentation that are possible if large 1685** allocations are avoided. This hint is normally off. 1686** </dd> 1687** 1688** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1689** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1690** interpreted as a boolean, which enables or disables the collection of 1691** memory allocation statistics. ^(When memory allocation statistics are 1692** disabled, the following SQLite interfaces become non-operational: 1693** <ul> 1694** <li> [sqlite3_memory_used()] 1695** <li> [sqlite3_memory_highwater()] 1696** <li> [sqlite3_soft_heap_limit64()] 1697** <li> [sqlite3_status64()] 1698** </ul>)^ 1699** ^Memory allocation statistics are enabled by default unless SQLite is 1700** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1701** allocation statistics are disabled by default. 1702** </dd> 1703** 1704** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1705** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1706** </dd> 1707** 1708** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1709** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1710** that SQLite can use for the database page cache with the default page 1711** cache implementation. 1712** This configuration option is a no-op if an application-define page 1713** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1714** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1715** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1716** and the number of cache lines (N). 1717** The sz argument should be the size of the largest database page 1718** (a power of two between 512 and 65536) plus some extra bytes for each 1719** page header. ^The number of extra bytes needed by the page header 1720** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1721** ^It is harmless, apart from the wasted memory, 1722** for the sz parameter to be larger than necessary. The pMem 1723** argument must be either a NULL pointer or a pointer to an 8-byte 1724** aligned block of memory of at least sz*N bytes, otherwise 1725** subsequent behavior is undefined. 1726** ^When pMem is not NULL, SQLite will strive to use the memory provided 1727** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1728** a page cache line is larger than sz bytes or if all of the pMem buffer 1729** is exhausted. 1730** ^If pMem is NULL and N is non-zero, then each database connection 1731** does an initial bulk allocation for page cache memory 1732** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1733** of -1024*N bytes if N is negative, . ^If additional 1734** page cache memory is needed beyond what is provided by the initial 1735** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1736** additional cache line. </dd> 1737** 1738** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1739** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1740** that SQLite will use for all of its dynamic memory allocation needs 1741** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1742** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1743** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1744** [SQLITE_ERROR] if invoked otherwise. 1745** ^There are three arguments to SQLITE_CONFIG_HEAP: 1746** An 8-byte aligned pointer to the memory, 1747** the number of bytes in the memory buffer, and the minimum allocation size. 1748** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1749** to using its default memory allocator (the system malloc() implementation), 1750** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1751** memory pointer is not NULL then the alternative memory 1752** allocator is engaged to handle all of SQLites memory allocation needs. 1753** The first pointer (the memory pointer) must be aligned to an 8-byte 1754** boundary or subsequent behavior of SQLite will be undefined. 1755** The minimum allocation size is capped at 2**12. Reasonable values 1756** for the minimum allocation size are 2**5 through 2**8.</dd> 1757** 1758** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1759** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1760** pointer to an instance of the [sqlite3_mutex_methods] structure. 1761** The argument specifies alternative low-level mutex routines to be used 1762** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1763** the content of the [sqlite3_mutex_methods] structure before the call to 1764** [sqlite3_config()] returns. ^If SQLite is compiled with 1765** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1766** the entire mutexing subsystem is omitted from the build and hence calls to 1767** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1768** return [SQLITE_ERROR].</dd> 1769** 1770** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1771** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1772** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1773** [sqlite3_mutex_methods] 1774** structure is filled with the currently defined mutex routines.)^ 1775** This option can be used to overload the default mutex allocation 1776** routines with a wrapper used to track mutex usage for performance 1777** profiling or testing, for example. ^If SQLite is compiled with 1778** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1779** the entire mutexing subsystem is omitted from the build and hence calls to 1780** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1781** return [SQLITE_ERROR].</dd> 1782** 1783** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1784** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1785** the default size of lookaside memory on each [database connection]. 1786** The first argument is the 1787** size of each lookaside buffer slot and the second is the number of 1788** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1789** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1790** option to [sqlite3_db_config()] can be used to change the lookaside 1791** configuration on individual connections.)^ </dd> 1792** 1793** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1794** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1795** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1796** the interface to a custom page cache implementation.)^ 1797** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1798** 1799** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1800** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1801** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1802** the current page cache implementation into that object.)^ </dd> 1803** 1804** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1805** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1806** global [error log]. 1807** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1808** function with a call signature of void(*)(void*,int,const char*), 1809** and a pointer to void. ^If the function pointer is not NULL, it is 1810** invoked by [sqlite3_log()] to process each logging event. ^If the 1811** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1812** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1813** passed through as the first parameter to the application-defined logger 1814** function whenever that function is invoked. ^The second parameter to 1815** the logger function is a copy of the first parameter to the corresponding 1816** [sqlite3_log()] call and is intended to be a [result code] or an 1817** [extended result code]. ^The third parameter passed to the logger is 1818** log message after formatting via [sqlite3_snprintf()]. 1819** The SQLite logging interface is not reentrant; the logger function 1820** supplied by the application must not invoke any SQLite interface. 1821** In a multi-threaded application, the application-defined logger 1822** function must be threadsafe. </dd> 1823** 1824** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1825** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1826** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1827** then URI handling is globally disabled.)^ ^If URI handling is globally 1828** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1829** [sqlite3_open16()] or 1830** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1831** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1832** connection is opened. ^If it is globally disabled, filenames are 1833** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1834** database connection is opened. ^(By default, URI handling is globally 1835** disabled. The default value may be changed by compiling with the 1836** [SQLITE_USE_URI] symbol defined.)^ 1837** 1838** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1839** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1840** argument which is interpreted as a boolean in order to enable or disable 1841** the use of covering indices for full table scans in the query optimizer. 1842** ^The default setting is determined 1843** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1844** if that compile-time option is omitted. 1845** The ability to disable the use of covering indices for full table scans 1846** is because some incorrectly coded legacy applications might malfunction 1847** when the optimization is enabled. Providing the ability to 1848** disable the optimization allows the older, buggy application code to work 1849** without change even with newer versions of SQLite. 1850** 1851** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1852** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1853** <dd> These options are obsolete and should not be used by new code. 1854** They are retained for backwards compatibility but are now no-ops. 1855** </dd> 1856** 1857** [[SQLITE_CONFIG_SQLLOG]] 1858** <dt>SQLITE_CONFIG_SQLLOG 1859** <dd>This option is only available if sqlite is compiled with the 1860** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1861** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1862** The second should be of type (void*). The callback is invoked by the library 1863** in three separate circumstances, identified by the value passed as the 1864** fourth parameter. If the fourth parameter is 0, then the database connection 1865** passed as the second argument has just been opened. The third argument 1866** points to a buffer containing the name of the main database file. If the 1867** fourth parameter is 1, then the SQL statement that the third parameter 1868** points to has just been executed. Or, if the fourth parameter is 2, then 1869** the connection being passed as the second parameter is being closed. The 1870** third parameter is passed NULL In this case. An example of using this 1871** configuration option can be seen in the "test_sqllog.c" source file in 1872** the canonical SQLite source tree.</dd> 1873** 1874** [[SQLITE_CONFIG_MMAP_SIZE]] 1875** <dt>SQLITE_CONFIG_MMAP_SIZE 1876** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1877** that are the default mmap size limit (the default setting for 1878** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1879** ^The default setting can be overridden by each database connection using 1880** either the [PRAGMA mmap_size] command, or by using the 1881** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1882** will be silently truncated if necessary so that it does not exceed the 1883** compile-time maximum mmap size set by the 1884** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1885** ^If either argument to this option is negative, then that argument is 1886** changed to its compile-time default. 1887** 1888** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1889** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1890** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1891** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1892** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1893** that specifies the maximum size of the created heap. 1894** 1895** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1896** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1897** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1898** is a pointer to an integer and writes into that integer the number of extra 1899** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1900** The amount of extra space required can change depending on the compiler, 1901** target platform, and SQLite version. 1902** 1903** [[SQLITE_CONFIG_PMASZ]] 1904** <dt>SQLITE_CONFIG_PMASZ 1905** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1906** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1907** sorter to that integer. The default minimum PMA Size is set by the 1908** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1909** to help with sort operations when multithreaded sorting 1910** is enabled (using the [PRAGMA threads] command) and the amount of content 1911** to be sorted exceeds the page size times the minimum of the 1912** [PRAGMA cache_size] setting and this value. 1913** 1914** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1915** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1916** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1917** becomes the [statement journal] spill-to-disk threshold. 1918** [Statement journals] are held in memory until their size (in bytes) 1919** exceeds this threshold, at which point they are written to disk. 1920** Or if the threshold is -1, statement journals are always held 1921** exclusively in memory. 1922** Since many statement journals never become large, setting the spill 1923** threshold to a value such as 64KiB can greatly reduce the amount of 1924** I/O required to support statement rollback. 1925** The default value for this setting is controlled by the 1926** [SQLITE_STMTJRNL_SPILL] compile-time option. 1927** </dl> 1928*/ 1929#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1930#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1931#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1932#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1933#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1934#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1935#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1936#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1937#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1938#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1939#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1940/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1941#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1942#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1943#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1944#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1945#define SQLITE_CONFIG_URI 17 /* int */ 1946#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1947#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1948#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1949#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1950#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1951#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1952#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1953#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1954#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1955#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1956 1957/* 1958** CAPI3REF: Database Connection Configuration Options 1959** 1960** These constants are the available integer configuration options that 1961** can be passed as the second argument to the [sqlite3_db_config()] interface. 1962** 1963** New configuration options may be added in future releases of SQLite. 1964** Existing configuration options might be discontinued. Applications 1965** should check the return code from [sqlite3_db_config()] to make sure that 1966** the call worked. ^The [sqlite3_db_config()] interface will return a 1967** non-zero [error code] if a discontinued or unsupported configuration option 1968** is invoked. 1969** 1970** <dl> 1971** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1972** <dd> ^This option takes three additional arguments that determine the 1973** [lookaside memory allocator] configuration for the [database connection]. 1974** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1975** pointer to a memory buffer to use for lookaside memory. 1976** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1977** may be NULL in which case SQLite will allocate the 1978** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1979** size of each lookaside buffer slot. ^The third argument is the number of 1980** slots. The size of the buffer in the first argument must be greater than 1981** or equal to the product of the second and third arguments. The buffer 1982** must be aligned to an 8-byte boundary. ^If the second argument to 1983** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1984** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1985** configuration for a database connection can only be changed when that 1986** connection is not currently using lookaside memory, or in other words 1987** when the "current value" returned by 1988** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1989** Any attempt to change the lookaside memory configuration when lookaside 1990** memory is in use leaves the configuration unchanged and returns 1991** [SQLITE_BUSY].)^</dd> 1992** 1993** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1994** <dd> ^This option is used to enable or disable the enforcement of 1995** [foreign key constraints]. There should be two additional arguments. 1996** The first argument is an integer which is 0 to disable FK enforcement, 1997** positive to enable FK enforcement or negative to leave FK enforcement 1998** unchanged. The second parameter is a pointer to an integer into which 1999** is written 0 or 1 to indicate whether FK enforcement is off or on 2000** following this call. The second parameter may be a NULL pointer, in 2001** which case the FK enforcement setting is not reported back. </dd> 2002** 2003** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2004** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2005** There should be two additional arguments. 2006** The first argument is an integer which is 0 to disable triggers, 2007** positive to enable triggers or negative to leave the setting unchanged. 2008** The second parameter is a pointer to an integer into which 2009** is written 0 or 1 to indicate whether triggers are disabled or enabled 2010** following this call. The second parameter may be a NULL pointer, in 2011** which case the trigger setting is not reported back. </dd> 2012** 2013** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2014** <dd> ^This option is used to enable or disable the two-argument 2015** version of the [fts3_tokenizer()] function which is part of the 2016** [FTS3] full-text search engine extension. 2017** There should be two additional arguments. 2018** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2019** positive to enable fts3_tokenizer() or negative to leave the setting 2020** unchanged. 2021** The second parameter is a pointer to an integer into which 2022** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2023** following this call. The second parameter may be a NULL pointer, in 2024** which case the new setting is not reported back. </dd> 2025** 2026** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2027** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2028** interface independently of the [load_extension()] SQL function. 2029** The [sqlite3_enable_load_extension()] API enables or disables both the 2030** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2031** There should be two additional arguments. 2032** When the first argument to this interface is 1, then only the C-API is 2033** enabled and the SQL function remains disabled. If the first argument to 2034** this interface is 0, then both the C-API and the SQL function are disabled. 2035** If the first argument is -1, then no changes are made to state of either the 2036** C-API or the SQL function. 2037** The second parameter is a pointer to an integer into which 2038** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2039** is disabled or enabled following this call. The second parameter may 2040** be a NULL pointer, in which case the new setting is not reported back. 2041** </dd> 2042** 2043** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2044** <dd> ^This option is used to change the name of the "main" database 2045** schema. ^The sole argument is a pointer to a constant UTF8 string 2046** which will become the new schema name in place of "main". ^SQLite 2047** does not make a copy of the new main schema name string, so the application 2048** must ensure that the argument passed into this DBCONFIG option is unchanged 2049** until after the database connection closes. 2050** </dd> 2051** 2052** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2053** <dd> Usually, when a database in wal mode is closed or detached from a 2054** database handle, SQLite checks if this will mean that there are now no 2055** connections at all to the database. If so, it performs a checkpoint 2056** operation before closing the connection. This option may be used to 2057** override this behaviour. The first parameter passed to this operation 2058** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2059** default) to enable them. The second parameter is a pointer to an integer 2060** into which is written 0 or 1 to indicate whether checkpoints-on-close 2061** have been disabled - 0 if they are not disabled, 1 if they are. 2062** </dd> 2063** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2064** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2065** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2066** a single SQL query statement will always use the same algorithm regardless 2067** of values of [bound parameters].)^ The QPSG disables some query optimizations 2068** that look at the values of bound parameters, which can make some queries 2069** slower. But the QPSG has the advantage of more predictable behavior. With 2070** the QPSG active, SQLite will always use the same query plan in the field as 2071** was used during testing in the lab. 2072** </dd> 2073** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2074** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2075** include output for any operations performed by trigger programs. This 2076** option is used to set or clear (the default) a flag that governs this 2077** behavior. The first parameter passed to this operation is an integer - 2078** non-zero to enable output for trigger programs, or zero to disable it. 2079** The second parameter is a pointer to an integer into which is written 2080** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2081** it is not disabled, 1 if it is. 2082** </dd> 2083** </dl> 2084*/ 2085#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2086#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2087#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2088#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2089#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2090#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2091#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2092#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2093#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2094#define SQLITE_DBCONFIG_MAX 1008 /* Largest DBCONFIG */ 2095 2096/* 2097** CAPI3REF: Enable Or Disable Extended Result Codes 2098** METHOD: sqlite3 2099** 2100** ^The sqlite3_extended_result_codes() routine enables or disables the 2101** [extended result codes] feature of SQLite. ^The extended result 2102** codes are disabled by default for historical compatibility. 2103*/ 2104int sqlite3_extended_result_codes(sqlite3*, int onoff); 2105 2106/* 2107** CAPI3REF: Last Insert Rowid 2108** METHOD: sqlite3 2109** 2110** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2111** has a unique 64-bit signed 2112** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2113** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2114** names are not also used by explicitly declared columns. ^If 2115** the table has a column of type [INTEGER PRIMARY KEY] then that column 2116** is another alias for the rowid. 2117** 2118** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2119** the most recent successful [INSERT] into a rowid table or [virtual table] 2120** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2121** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2122** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2123** zero. 2124** 2125** As well as being set automatically as rows are inserted into database 2126** tables, the value returned by this function may be set explicitly by 2127** [sqlite3_set_last_insert_rowid()] 2128** 2129** Some virtual table implementations may INSERT rows into rowid tables as 2130** part of committing a transaction (e.g. to flush data accumulated in memory 2131** to disk). In this case subsequent calls to this function return the rowid 2132** associated with these internal INSERT operations, which leads to 2133** unintuitive results. Virtual table implementations that do write to rowid 2134** tables in this way can avoid this problem by restoring the original 2135** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2136** control to the user. 2137** 2138** ^(If an [INSERT] occurs within a trigger then this routine will 2139** return the [rowid] of the inserted row as long as the trigger is 2140** running. Once the trigger program ends, the value returned 2141** by this routine reverts to what it was before the trigger was fired.)^ 2142** 2143** ^An [INSERT] that fails due to a constraint violation is not a 2144** successful [INSERT] and does not change the value returned by this 2145** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2146** and INSERT OR ABORT make no changes to the return value of this 2147** routine when their insertion fails. ^(When INSERT OR REPLACE 2148** encounters a constraint violation, it does not fail. The 2149** INSERT continues to completion after deleting rows that caused 2150** the constraint problem so INSERT OR REPLACE will always change 2151** the return value of this interface.)^ 2152** 2153** ^For the purposes of this routine, an [INSERT] is considered to 2154** be successful even if it is subsequently rolled back. 2155** 2156** This function is accessible to SQL statements via the 2157** [last_insert_rowid() SQL function]. 2158** 2159** If a separate thread performs a new [INSERT] on the same 2160** database connection while the [sqlite3_last_insert_rowid()] 2161** function is running and thus changes the last insert [rowid], 2162** then the value returned by [sqlite3_last_insert_rowid()] is 2163** unpredictable and might not equal either the old or the new 2164** last insert [rowid]. 2165*/ 2166sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2167 2168/* 2169** CAPI3REF: Set the Last Insert Rowid value. 2170** METHOD: sqlite3 2171** 2172** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2173** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2174** without inserting a row into the database. 2175*/ 2176void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2177 2178/* 2179** CAPI3REF: Count The Number Of Rows Modified 2180** METHOD: sqlite3 2181** 2182** ^This function returns the number of rows modified, inserted or 2183** deleted by the most recently completed INSERT, UPDATE or DELETE 2184** statement on the database connection specified by the only parameter. 2185** ^Executing any other type of SQL statement does not modify the value 2186** returned by this function. 2187** 2188** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2189** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2190** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2191** 2192** Changes to a view that are intercepted by 2193** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2194** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2195** DELETE statement run on a view is always zero. Only changes made to real 2196** tables are counted. 2197** 2198** Things are more complicated if the sqlite3_changes() function is 2199** executed while a trigger program is running. This may happen if the 2200** program uses the [changes() SQL function], or if some other callback 2201** function invokes sqlite3_changes() directly. Essentially: 2202** 2203** <ul> 2204** <li> ^(Before entering a trigger program the value returned by 2205** sqlite3_changes() function is saved. After the trigger program 2206** has finished, the original value is restored.)^ 2207** 2208** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2209** statement sets the value returned by sqlite3_changes() 2210** upon completion as normal. Of course, this value will not include 2211** any changes performed by sub-triggers, as the sqlite3_changes() 2212** value will be saved and restored after each sub-trigger has run.)^ 2213** </ul> 2214** 2215** ^This means that if the changes() SQL function (or similar) is used 2216** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2217** returns the value as set when the calling statement began executing. 2218** ^If it is used by the second or subsequent such statement within a trigger 2219** program, the value returned reflects the number of rows modified by the 2220** previous INSERT, UPDATE or DELETE statement within the same trigger. 2221** 2222** See also the [sqlite3_total_changes()] interface, the 2223** [count_changes pragma], and the [changes() SQL function]. 2224** 2225** If a separate thread makes changes on the same database connection 2226** while [sqlite3_changes()] is running then the value returned 2227** is unpredictable and not meaningful. 2228*/ 2229int sqlite3_changes(sqlite3*); 2230 2231/* 2232** CAPI3REF: Total Number Of Rows Modified 2233** METHOD: sqlite3 2234** 2235** ^This function returns the total number of rows inserted, modified or 2236** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2237** since the database connection was opened, including those executed as 2238** part of trigger programs. ^Executing any other type of SQL statement 2239** does not affect the value returned by sqlite3_total_changes(). 2240** 2241** ^Changes made as part of [foreign key actions] are included in the 2242** count, but those made as part of REPLACE constraint resolution are 2243** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2244** are not counted. 2245** 2246** See also the [sqlite3_changes()] interface, the 2247** [count_changes pragma], and the [total_changes() SQL function]. 2248** 2249** If a separate thread makes changes on the same database connection 2250** while [sqlite3_total_changes()] is running then the value 2251** returned is unpredictable and not meaningful. 2252*/ 2253int sqlite3_total_changes(sqlite3*); 2254 2255/* 2256** CAPI3REF: Interrupt A Long-Running Query 2257** METHOD: sqlite3 2258** 2259** ^This function causes any pending database operation to abort and 2260** return at its earliest opportunity. This routine is typically 2261** called in response to a user action such as pressing "Cancel" 2262** or Ctrl-C where the user wants a long query operation to halt 2263** immediately. 2264** 2265** ^It is safe to call this routine from a thread different from the 2266** thread that is currently running the database operation. But it 2267** is not safe to call this routine with a [database connection] that 2268** is closed or might close before sqlite3_interrupt() returns. 2269** 2270** ^If an SQL operation is very nearly finished at the time when 2271** sqlite3_interrupt() is called, then it might not have an opportunity 2272** to be interrupted and might continue to completion. 2273** 2274** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2275** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2276** that is inside an explicit transaction, then the entire transaction 2277** will be rolled back automatically. 2278** 2279** ^The sqlite3_interrupt(D) call is in effect until all currently running 2280** SQL statements on [database connection] D complete. ^Any new SQL statements 2281** that are started after the sqlite3_interrupt() call and before the 2282** running statements reaches zero are interrupted as if they had been 2283** running prior to the sqlite3_interrupt() call. ^New SQL statements 2284** that are started after the running statement count reaches zero are 2285** not effected by the sqlite3_interrupt(). 2286** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2287** SQL statements is a no-op and has no effect on SQL statements 2288** that are started after the sqlite3_interrupt() call returns. 2289*/ 2290void sqlite3_interrupt(sqlite3*); 2291 2292/* 2293** CAPI3REF: Determine If An SQL Statement Is Complete 2294** 2295** These routines are useful during command-line input to determine if the 2296** currently entered text seems to form a complete SQL statement or 2297** if additional input is needed before sending the text into 2298** SQLite for parsing. ^These routines return 1 if the input string 2299** appears to be a complete SQL statement. ^A statement is judged to be 2300** complete if it ends with a semicolon token and is not a prefix of a 2301** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2302** string literals or quoted identifier names or comments are not 2303** independent tokens (they are part of the token in which they are 2304** embedded) and thus do not count as a statement terminator. ^Whitespace 2305** and comments that follow the final semicolon are ignored. 2306** 2307** ^These routines return 0 if the statement is incomplete. ^If a 2308** memory allocation fails, then SQLITE_NOMEM is returned. 2309** 2310** ^These routines do not parse the SQL statements thus 2311** will not detect syntactically incorrect SQL. 2312** 2313** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2314** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2315** automatically by sqlite3_complete16(). If that initialization fails, 2316** then the return value from sqlite3_complete16() will be non-zero 2317** regardless of whether or not the input SQL is complete.)^ 2318** 2319** The input to [sqlite3_complete()] must be a zero-terminated 2320** UTF-8 string. 2321** 2322** The input to [sqlite3_complete16()] must be a zero-terminated 2323** UTF-16 string in native byte order. 2324*/ 2325int sqlite3_complete(const char *sql); 2326int sqlite3_complete16(const void *sql); 2327 2328/* 2329** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2330** KEYWORDS: {busy-handler callback} {busy handler} 2331** METHOD: sqlite3 2332** 2333** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2334** that might be invoked with argument P whenever 2335** an attempt is made to access a database table associated with 2336** [database connection] D when another thread 2337** or process has the table locked. 2338** The sqlite3_busy_handler() interface is used to implement 2339** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2340** 2341** ^If the busy callback is NULL, then [SQLITE_BUSY] 2342** is returned immediately upon encountering the lock. ^If the busy callback 2343** is not NULL, then the callback might be invoked with two arguments. 2344** 2345** ^The first argument to the busy handler is a copy of the void* pointer which 2346** is the third argument to sqlite3_busy_handler(). ^The second argument to 2347** the busy handler callback is the number of times that the busy handler has 2348** been invoked previously for the same locking event. ^If the 2349** busy callback returns 0, then no additional attempts are made to 2350** access the database and [SQLITE_BUSY] is returned 2351** to the application. 2352** ^If the callback returns non-zero, then another attempt 2353** is made to access the database and the cycle repeats. 2354** 2355** The presence of a busy handler does not guarantee that it will be invoked 2356** when there is lock contention. ^If SQLite determines that invoking the busy 2357** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2358** to the application instead of invoking the 2359** busy handler. 2360** Consider a scenario where one process is holding a read lock that 2361** it is trying to promote to a reserved lock and 2362** a second process is holding a reserved lock that it is trying 2363** to promote to an exclusive lock. The first process cannot proceed 2364** because it is blocked by the second and the second process cannot 2365** proceed because it is blocked by the first. If both processes 2366** invoke the busy handlers, neither will make any progress. Therefore, 2367** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2368** will induce the first process to release its read lock and allow 2369** the second process to proceed. 2370** 2371** ^The default busy callback is NULL. 2372** 2373** ^(There can only be a single busy handler defined for each 2374** [database connection]. Setting a new busy handler clears any 2375** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2376** or evaluating [PRAGMA busy_timeout=N] will change the 2377** busy handler and thus clear any previously set busy handler. 2378** 2379** The busy callback should not take any actions which modify the 2380** database connection that invoked the busy handler. In other words, 2381** the busy handler is not reentrant. Any such actions 2382** result in undefined behavior. 2383** 2384** A busy handler must not close the database connection 2385** or [prepared statement] that invoked the busy handler. 2386*/ 2387int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2388 2389/* 2390** CAPI3REF: Set A Busy Timeout 2391** METHOD: sqlite3 2392** 2393** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2394** for a specified amount of time when a table is locked. ^The handler 2395** will sleep multiple times until at least "ms" milliseconds of sleeping 2396** have accumulated. ^After at least "ms" milliseconds of sleeping, 2397** the handler returns 0 which causes [sqlite3_step()] to return 2398** [SQLITE_BUSY]. 2399** 2400** ^Calling this routine with an argument less than or equal to zero 2401** turns off all busy handlers. 2402** 2403** ^(There can only be a single busy handler for a particular 2404** [database connection] at any given moment. If another busy handler 2405** was defined (using [sqlite3_busy_handler()]) prior to calling 2406** this routine, that other busy handler is cleared.)^ 2407** 2408** See also: [PRAGMA busy_timeout] 2409*/ 2410int sqlite3_busy_timeout(sqlite3*, int ms); 2411 2412/* 2413** CAPI3REF: Convenience Routines For Running Queries 2414** METHOD: sqlite3 2415** 2416** This is a legacy interface that is preserved for backwards compatibility. 2417** Use of this interface is not recommended. 2418** 2419** Definition: A <b>result table</b> is memory data structure created by the 2420** [sqlite3_get_table()] interface. A result table records the 2421** complete query results from one or more queries. 2422** 2423** The table conceptually has a number of rows and columns. But 2424** these numbers are not part of the result table itself. These 2425** numbers are obtained separately. Let N be the number of rows 2426** and M be the number of columns. 2427** 2428** A result table is an array of pointers to zero-terminated UTF-8 strings. 2429** There are (N+1)*M elements in the array. The first M pointers point 2430** to zero-terminated strings that contain the names of the columns. 2431** The remaining entries all point to query results. NULL values result 2432** in NULL pointers. All other values are in their UTF-8 zero-terminated 2433** string representation as returned by [sqlite3_column_text()]. 2434** 2435** A result table might consist of one or more memory allocations. 2436** It is not safe to pass a result table directly to [sqlite3_free()]. 2437** A result table should be deallocated using [sqlite3_free_table()]. 2438** 2439** ^(As an example of the result table format, suppose a query result 2440** is as follows: 2441** 2442** <blockquote><pre> 2443** Name | Age 2444** ----------------------- 2445** Alice | 43 2446** Bob | 28 2447** Cindy | 21 2448** </pre></blockquote> 2449** 2450** There are two column (M==2) and three rows (N==3). Thus the 2451** result table has 8 entries. Suppose the result table is stored 2452** in an array names azResult. Then azResult holds this content: 2453** 2454** <blockquote><pre> 2455** azResult[0] = "Name"; 2456** azResult[1] = "Age"; 2457** azResult[2] = "Alice"; 2458** azResult[3] = "43"; 2459** azResult[4] = "Bob"; 2460** azResult[5] = "28"; 2461** azResult[6] = "Cindy"; 2462** azResult[7] = "21"; 2463** </pre></blockquote>)^ 2464** 2465** ^The sqlite3_get_table() function evaluates one or more 2466** semicolon-separated SQL statements in the zero-terminated UTF-8 2467** string of its 2nd parameter and returns a result table to the 2468** pointer given in its 3rd parameter. 2469** 2470** After the application has finished with the result from sqlite3_get_table(), 2471** it must pass the result table pointer to sqlite3_free_table() in order to 2472** release the memory that was malloced. Because of the way the 2473** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2474** function must not try to call [sqlite3_free()] directly. Only 2475** [sqlite3_free_table()] is able to release the memory properly and safely. 2476** 2477** The sqlite3_get_table() interface is implemented as a wrapper around 2478** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2479** to any internal data structures of SQLite. It uses only the public 2480** interface defined here. As a consequence, errors that occur in the 2481** wrapper layer outside of the internal [sqlite3_exec()] call are not 2482** reflected in subsequent calls to [sqlite3_errcode()] or 2483** [sqlite3_errmsg()]. 2484*/ 2485int sqlite3_get_table( 2486 sqlite3 *db, /* An open database */ 2487 const char *zSql, /* SQL to be evaluated */ 2488 char ***pazResult, /* Results of the query */ 2489 int *pnRow, /* Number of result rows written here */ 2490 int *pnColumn, /* Number of result columns written here */ 2491 char **pzErrmsg /* Error msg written here */ 2492); 2493void sqlite3_free_table(char **result); 2494 2495/* 2496** CAPI3REF: Formatted String Printing Functions 2497** 2498** These routines are work-alikes of the "printf()" family of functions 2499** from the standard C library. 2500** These routines understand most of the common K&R formatting options, 2501** plus some additional non-standard formats, detailed below. 2502** Note that some of the more obscure formatting options from recent 2503** C-library standards are omitted from this implementation. 2504** 2505** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2506** results into memory obtained from [sqlite3_malloc()]. 2507** The strings returned by these two routines should be 2508** released by [sqlite3_free()]. ^Both routines return a 2509** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2510** memory to hold the resulting string. 2511** 2512** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2513** the standard C library. The result is written into the 2514** buffer supplied as the second parameter whose size is given by 2515** the first parameter. Note that the order of the 2516** first two parameters is reversed from snprintf().)^ This is an 2517** historical accident that cannot be fixed without breaking 2518** backwards compatibility. ^(Note also that sqlite3_snprintf() 2519** returns a pointer to its buffer instead of the number of 2520** characters actually written into the buffer.)^ We admit that 2521** the number of characters written would be a more useful return 2522** value but we cannot change the implementation of sqlite3_snprintf() 2523** now without breaking compatibility. 2524** 2525** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2526** guarantees that the buffer is always zero-terminated. ^The first 2527** parameter "n" is the total size of the buffer, including space for 2528** the zero terminator. So the longest string that can be completely 2529** written will be n-1 characters. 2530** 2531** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2532** 2533** These routines all implement some additional formatting 2534** options that are useful for constructing SQL statements. 2535** All of the usual printf() formatting options apply. In addition, there 2536** is are "%q", "%Q", "%w" and "%z" options. 2537** 2538** ^(The %q option works like %s in that it substitutes a nul-terminated 2539** string from the argument list. But %q also doubles every '\'' character. 2540** %q is designed for use inside a string literal.)^ By doubling each '\'' 2541** character it escapes that character and allows it to be inserted into 2542** the string. 2543** 2544** For example, assume the string variable zText contains text as follows: 2545** 2546** <blockquote><pre> 2547** char *zText = "It's a happy day!"; 2548** </pre></blockquote> 2549** 2550** One can use this text in an SQL statement as follows: 2551** 2552** <blockquote><pre> 2553** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2554** sqlite3_exec(db, zSQL, 0, 0, 0); 2555** sqlite3_free(zSQL); 2556** </pre></blockquote> 2557** 2558** Because the %q format string is used, the '\'' character in zText 2559** is escaped and the SQL generated is as follows: 2560** 2561** <blockquote><pre> 2562** INSERT INTO table1 VALUES('It''s a happy day!') 2563** </pre></blockquote> 2564** 2565** This is correct. Had we used %s instead of %q, the generated SQL 2566** would have looked like this: 2567** 2568** <blockquote><pre> 2569** INSERT INTO table1 VALUES('It's a happy day!'); 2570** </pre></blockquote> 2571** 2572** This second example is an SQL syntax error. As a general rule you should 2573** always use %q instead of %s when inserting text into a string literal. 2574** 2575** ^(The %Q option works like %q except it also adds single quotes around 2576** the outside of the total string. Additionally, if the parameter in the 2577** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2578** single quotes).)^ So, for example, one could say: 2579** 2580** <blockquote><pre> 2581** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2582** sqlite3_exec(db, zSQL, 0, 0, 0); 2583** sqlite3_free(zSQL); 2584** </pre></blockquote> 2585** 2586** The code above will render a correct SQL statement in the zSQL 2587** variable even if the zText variable is a NULL pointer. 2588** 2589** ^(The "%w" formatting option is like "%q" except that it expects to 2590** be contained within double-quotes instead of single quotes, and it 2591** escapes the double-quote character instead of the single-quote 2592** character.)^ The "%w" formatting option is intended for safely inserting 2593** table and column names into a constructed SQL statement. 2594** 2595** ^(The "%z" formatting option works like "%s" but with the 2596** addition that after the string has been read and copied into 2597** the result, [sqlite3_free()] is called on the input string.)^ 2598*/ 2599char *sqlite3_mprintf(const char*,...); 2600char *sqlite3_vmprintf(const char*, va_list); 2601char *sqlite3_snprintf(int,char*,const char*, ...); 2602char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2603 2604/* 2605** CAPI3REF: Memory Allocation Subsystem 2606** 2607** The SQLite core uses these three routines for all of its own 2608** internal memory allocation needs. "Core" in the previous sentence 2609** does not include operating-system specific VFS implementation. The 2610** Windows VFS uses native malloc() and free() for some operations. 2611** 2612** ^The sqlite3_malloc() routine returns a pointer to a block 2613** of memory at least N bytes in length, where N is the parameter. 2614** ^If sqlite3_malloc() is unable to obtain sufficient free 2615** memory, it returns a NULL pointer. ^If the parameter N to 2616** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2617** a NULL pointer. 2618** 2619** ^The sqlite3_malloc64(N) routine works just like 2620** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2621** of a signed 32-bit integer. 2622** 2623** ^Calling sqlite3_free() with a pointer previously returned 2624** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2625** that it might be reused. ^The sqlite3_free() routine is 2626** a no-op if is called with a NULL pointer. Passing a NULL pointer 2627** to sqlite3_free() is harmless. After being freed, memory 2628** should neither be read nor written. Even reading previously freed 2629** memory might result in a segmentation fault or other severe error. 2630** Memory corruption, a segmentation fault, or other severe error 2631** might result if sqlite3_free() is called with a non-NULL pointer that 2632** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2633** 2634** ^The sqlite3_realloc(X,N) interface attempts to resize a 2635** prior memory allocation X to be at least N bytes. 2636** ^If the X parameter to sqlite3_realloc(X,N) 2637** is a NULL pointer then its behavior is identical to calling 2638** sqlite3_malloc(N). 2639** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2640** negative then the behavior is exactly the same as calling 2641** sqlite3_free(X). 2642** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2643** of at least N bytes in size or NULL if insufficient memory is available. 2644** ^If M is the size of the prior allocation, then min(N,M) bytes 2645** of the prior allocation are copied into the beginning of buffer returned 2646** by sqlite3_realloc(X,N) and the prior allocation is freed. 2647** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2648** prior allocation is not freed. 2649** 2650** ^The sqlite3_realloc64(X,N) interfaces works the same as 2651** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2652** of a 32-bit signed integer. 2653** 2654** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2655** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2656** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2657** ^The value returned by sqlite3_msize(X) might be larger than the number 2658** of bytes requested when X was allocated. ^If X is a NULL pointer then 2659** sqlite3_msize(X) returns zero. If X points to something that is not 2660** the beginning of memory allocation, or if it points to a formerly 2661** valid memory allocation that has now been freed, then the behavior 2662** of sqlite3_msize(X) is undefined and possibly harmful. 2663** 2664** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2665** sqlite3_malloc64(), and sqlite3_realloc64() 2666** is always aligned to at least an 8 byte boundary, or to a 2667** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2668** option is used. 2669** 2670** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2671** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2672** implementation of these routines to be omitted. That capability 2673** is no longer provided. Only built-in memory allocators can be used. 2674** 2675** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2676** the system malloc() and free() directly when converting 2677** filenames between the UTF-8 encoding used by SQLite 2678** and whatever filename encoding is used by the particular Windows 2679** installation. Memory allocation errors were detected, but 2680** they were reported back as [SQLITE_CANTOPEN] or 2681** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2682** 2683** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2684** must be either NULL or else pointers obtained from a prior 2685** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2686** not yet been released. 2687** 2688** The application must not read or write any part of 2689** a block of memory after it has been released using 2690** [sqlite3_free()] or [sqlite3_realloc()]. 2691*/ 2692void *sqlite3_malloc(int); 2693void *sqlite3_malloc64(sqlite3_uint64); 2694void *sqlite3_realloc(void*, int); 2695void *sqlite3_realloc64(void*, sqlite3_uint64); 2696void sqlite3_free(void*); 2697sqlite3_uint64 sqlite3_msize(void*); 2698 2699/* 2700** CAPI3REF: Memory Allocator Statistics 2701** 2702** SQLite provides these two interfaces for reporting on the status 2703** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2704** routines, which form the built-in memory allocation subsystem. 2705** 2706** ^The [sqlite3_memory_used()] routine returns the number of bytes 2707** of memory currently outstanding (malloced but not freed). 2708** ^The [sqlite3_memory_highwater()] routine returns the maximum 2709** value of [sqlite3_memory_used()] since the high-water mark 2710** was last reset. ^The values returned by [sqlite3_memory_used()] and 2711** [sqlite3_memory_highwater()] include any overhead 2712** added by SQLite in its implementation of [sqlite3_malloc()], 2713** but not overhead added by the any underlying system library 2714** routines that [sqlite3_malloc()] may call. 2715** 2716** ^The memory high-water mark is reset to the current value of 2717** [sqlite3_memory_used()] if and only if the parameter to 2718** [sqlite3_memory_highwater()] is true. ^The value returned 2719** by [sqlite3_memory_highwater(1)] is the high-water mark 2720** prior to the reset. 2721*/ 2722sqlite3_int64 sqlite3_memory_used(void); 2723sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2724 2725/* 2726** CAPI3REF: Pseudo-Random Number Generator 2727** 2728** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2729** select random [ROWID | ROWIDs] when inserting new records into a table that 2730** already uses the largest possible [ROWID]. The PRNG is also used for 2731** the build-in random() and randomblob() SQL functions. This interface allows 2732** applications to access the same PRNG for other purposes. 2733** 2734** ^A call to this routine stores N bytes of randomness into buffer P. 2735** ^The P parameter can be a NULL pointer. 2736** 2737** ^If this routine has not been previously called or if the previous 2738** call had N less than one or a NULL pointer for P, then the PRNG is 2739** seeded using randomness obtained from the xRandomness method of 2740** the default [sqlite3_vfs] object. 2741** ^If the previous call to this routine had an N of 1 or more and a 2742** non-NULL P then the pseudo-randomness is generated 2743** internally and without recourse to the [sqlite3_vfs] xRandomness 2744** method. 2745*/ 2746void sqlite3_randomness(int N, void *P); 2747 2748/* 2749** CAPI3REF: Compile-Time Authorization Callbacks 2750** METHOD: sqlite3 2751** KEYWORDS: {authorizer callback} 2752** 2753** ^This routine registers an authorizer callback with a particular 2754** [database connection], supplied in the first argument. 2755** ^The authorizer callback is invoked as SQL statements are being compiled 2756** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2757** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2758** and [sqlite3_prepare16_v3()]. ^At various 2759** points during the compilation process, as logic is being created 2760** to perform various actions, the authorizer callback is invoked to 2761** see if those actions are allowed. ^The authorizer callback should 2762** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2763** specific action but allow the SQL statement to continue to be 2764** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2765** rejected with an error. ^If the authorizer callback returns 2766** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2767** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2768** the authorizer will fail with an error message. 2769** 2770** When the callback returns [SQLITE_OK], that means the operation 2771** requested is ok. ^When the callback returns [SQLITE_DENY], the 2772** [sqlite3_prepare_v2()] or equivalent call that triggered the 2773** authorizer will fail with an error message explaining that 2774** access is denied. 2775** 2776** ^The first parameter to the authorizer callback is a copy of the third 2777** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2778** to the callback is an integer [SQLITE_COPY | action code] that specifies 2779** the particular action to be authorized. ^The third through sixth parameters 2780** to the callback are either NULL pointers or zero-terminated strings 2781** that contain additional details about the action to be authorized. 2782** Applications must always be prepared to encounter a NULL pointer in any 2783** of the third through the sixth parameters of the authorization callback. 2784** 2785** ^If the action code is [SQLITE_READ] 2786** and the callback returns [SQLITE_IGNORE] then the 2787** [prepared statement] statement is constructed to substitute 2788** a NULL value in place of the table column that would have 2789** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2790** return can be used to deny an untrusted user access to individual 2791** columns of a table. 2792** ^When a table is referenced by a [SELECT] but no column values are 2793** extracted from that table (for example in a query like 2794** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2795** is invoked once for that table with a column name that is an empty string. 2796** ^If the action code is [SQLITE_DELETE] and the callback returns 2797** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2798** [truncate optimization] is disabled and all rows are deleted individually. 2799** 2800** An authorizer is used when [sqlite3_prepare | preparing] 2801** SQL statements from an untrusted source, to ensure that the SQL statements 2802** do not try to access data they are not allowed to see, or that they do not 2803** try to execute malicious statements that damage the database. For 2804** example, an application may allow a user to enter arbitrary 2805** SQL queries for evaluation by a database. But the application does 2806** not want the user to be able to make arbitrary changes to the 2807** database. An authorizer could then be put in place while the 2808** user-entered SQL is being [sqlite3_prepare | prepared] that 2809** disallows everything except [SELECT] statements. 2810** 2811** Applications that need to process SQL from untrusted sources 2812** might also consider lowering resource limits using [sqlite3_limit()] 2813** and limiting database size using the [max_page_count] [PRAGMA] 2814** in addition to using an authorizer. 2815** 2816** ^(Only a single authorizer can be in place on a database connection 2817** at a time. Each call to sqlite3_set_authorizer overrides the 2818** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2819** The authorizer is disabled by default. 2820** 2821** The authorizer callback must not do anything that will modify 2822** the database connection that invoked the authorizer callback. 2823** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2824** database connections for the meaning of "modify" in this paragraph. 2825** 2826** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2827** statement might be re-prepared during [sqlite3_step()] due to a 2828** schema change. Hence, the application should ensure that the 2829** correct authorizer callback remains in place during the [sqlite3_step()]. 2830** 2831** ^Note that the authorizer callback is invoked only during 2832** [sqlite3_prepare()] or its variants. Authorization is not 2833** performed during statement evaluation in [sqlite3_step()], unless 2834** as stated in the previous paragraph, sqlite3_step() invokes 2835** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2836*/ 2837int sqlite3_set_authorizer( 2838 sqlite3*, 2839 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2840 void *pUserData 2841); 2842 2843/* 2844** CAPI3REF: Authorizer Return Codes 2845** 2846** The [sqlite3_set_authorizer | authorizer callback function] must 2847** return either [SQLITE_OK] or one of these two constants in order 2848** to signal SQLite whether or not the action is permitted. See the 2849** [sqlite3_set_authorizer | authorizer documentation] for additional 2850** information. 2851** 2852** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2853** returned from the [sqlite3_vtab_on_conflict()] interface. 2854*/ 2855#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2856#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2857 2858/* 2859** CAPI3REF: Authorizer Action Codes 2860** 2861** The [sqlite3_set_authorizer()] interface registers a callback function 2862** that is invoked to authorize certain SQL statement actions. The 2863** second parameter to the callback is an integer code that specifies 2864** what action is being authorized. These are the integer action codes that 2865** the authorizer callback may be passed. 2866** 2867** These action code values signify what kind of operation is to be 2868** authorized. The 3rd and 4th parameters to the authorization 2869** callback function will be parameters or NULL depending on which of these 2870** codes is used as the second parameter. ^(The 5th parameter to the 2871** authorizer callback is the name of the database ("main", "temp", 2872** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2873** is the name of the inner-most trigger or view that is responsible for 2874** the access attempt or NULL if this access attempt is directly from 2875** top-level SQL code. 2876*/ 2877/******************************************* 3rd ************ 4th ***********/ 2878#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2879#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2880#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2881#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2882#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2883#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2884#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2885#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2886#define SQLITE_DELETE 9 /* Table Name NULL */ 2887#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2888#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2889#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2890#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2891#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2892#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2893#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2894#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2895#define SQLITE_INSERT 18 /* Table Name NULL */ 2896#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2897#define SQLITE_READ 20 /* Table Name Column Name */ 2898#define SQLITE_SELECT 21 /* NULL NULL */ 2899#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2900#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2901#define SQLITE_ATTACH 24 /* Filename NULL */ 2902#define SQLITE_DETACH 25 /* Database Name NULL */ 2903#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2904#define SQLITE_REINDEX 27 /* Index Name NULL */ 2905#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2906#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2907#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2908#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2909#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2910#define SQLITE_COPY 0 /* No longer used */ 2911#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2912 2913/* 2914** CAPI3REF: Tracing And Profiling Functions 2915** METHOD: sqlite3 2916** 2917** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2918** instead of the routines described here. 2919** 2920** These routines register callback functions that can be used for 2921** tracing and profiling the execution of SQL statements. 2922** 2923** ^The callback function registered by sqlite3_trace() is invoked at 2924** various times when an SQL statement is being run by [sqlite3_step()]. 2925** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2926** SQL statement text as the statement first begins executing. 2927** ^(Additional sqlite3_trace() callbacks might occur 2928** as each triggered subprogram is entered. The callbacks for triggers 2929** contain a UTF-8 SQL comment that identifies the trigger.)^ 2930** 2931** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2932** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2933** 2934** ^The callback function registered by sqlite3_profile() is invoked 2935** as each SQL statement finishes. ^The profile callback contains 2936** the original statement text and an estimate of wall-clock time 2937** of how long that statement took to run. ^The profile callback 2938** time is in units of nanoseconds, however the current implementation 2939** is only capable of millisecond resolution so the six least significant 2940** digits in the time are meaningless. Future versions of SQLite 2941** might provide greater resolution on the profiler callback. The 2942** sqlite3_profile() function is considered experimental and is 2943** subject to change in future versions of SQLite. 2944*/ 2945SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2946 void(*xTrace)(void*,const char*), void*); 2947SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2948 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2949 2950/* 2951** CAPI3REF: SQL Trace Event Codes 2952** KEYWORDS: SQLITE_TRACE 2953** 2954** These constants identify classes of events that can be monitored 2955** using the [sqlite3_trace_v2()] tracing logic. The third argument 2956** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2957** the following constants. ^The first argument to the trace callback 2958** is one of the following constants. 2959** 2960** New tracing constants may be added in future releases. 2961** 2962** ^A trace callback has four arguments: xCallback(T,C,P,X). 2963** ^The T argument is one of the integer type codes above. 2964** ^The C argument is a copy of the context pointer passed in as the 2965** fourth argument to [sqlite3_trace_v2()]. 2966** The P and X arguments are pointers whose meanings depend on T. 2967** 2968** <dl> 2969** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2970** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2971** first begins running and possibly at other times during the 2972** execution of the prepared statement, such as at the start of each 2973** trigger subprogram. ^The P argument is a pointer to the 2974** [prepared statement]. ^The X argument is a pointer to a string which 2975** is the unexpanded SQL text of the prepared statement or an SQL comment 2976** that indicates the invocation of a trigger. ^The callback can compute 2977** the same text that would have been returned by the legacy [sqlite3_trace()] 2978** interface by using the X argument when X begins with "--" and invoking 2979** [sqlite3_expanded_sql(P)] otherwise. 2980** 2981** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2982** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2983** information as is provided by the [sqlite3_profile()] callback. 2984** ^The P argument is a pointer to the [prepared statement] and the 2985** X argument points to a 64-bit integer which is the estimated of 2986** the number of nanosecond that the prepared statement took to run. 2987** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2988** 2989** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2990** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2991** statement generates a single row of result. 2992** ^The P argument is a pointer to the [prepared statement] and the 2993** X argument is unused. 2994** 2995** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2996** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2997** connection closes. 2998** ^The P argument is a pointer to the [database connection] object 2999** and the X argument is unused. 3000** </dl> 3001*/ 3002#define SQLITE_TRACE_STMT 0x01 3003#define SQLITE_TRACE_PROFILE 0x02 3004#define SQLITE_TRACE_ROW 0x04 3005#define SQLITE_TRACE_CLOSE 0x08 3006 3007/* 3008** CAPI3REF: SQL Trace Hook 3009** METHOD: sqlite3 3010** 3011** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3012** function X against [database connection] D, using property mask M 3013** and context pointer P. ^If the X callback is 3014** NULL or if the M mask is zero, then tracing is disabled. The 3015** M argument should be the bitwise OR-ed combination of 3016** zero or more [SQLITE_TRACE] constants. 3017** 3018** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3019** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3020** 3021** ^The X callback is invoked whenever any of the events identified by 3022** mask M occur. ^The integer return value from the callback is currently 3023** ignored, though this may change in future releases. Callback 3024** implementations should return zero to ensure future compatibility. 3025** 3026** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3027** ^The T argument is one of the [SQLITE_TRACE] 3028** constants to indicate why the callback was invoked. 3029** ^The C argument is a copy of the context pointer. 3030** The P and X arguments are pointers whose meanings depend on T. 3031** 3032** The sqlite3_trace_v2() interface is intended to replace the legacy 3033** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3034** are deprecated. 3035*/ 3036int sqlite3_trace_v2( 3037 sqlite3*, 3038 unsigned uMask, 3039 int(*xCallback)(unsigned,void*,void*,void*), 3040 void *pCtx 3041); 3042 3043/* 3044** CAPI3REF: Query Progress Callbacks 3045** METHOD: sqlite3 3046** 3047** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3048** function X to be invoked periodically during long running calls to 3049** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3050** database connection D. An example use for this 3051** interface is to keep a GUI updated during a large query. 3052** 3053** ^The parameter P is passed through as the only parameter to the 3054** callback function X. ^The parameter N is the approximate number of 3055** [virtual machine instructions] that are evaluated between successive 3056** invocations of the callback X. ^If N is less than one then the progress 3057** handler is disabled. 3058** 3059** ^Only a single progress handler may be defined at one time per 3060** [database connection]; setting a new progress handler cancels the 3061** old one. ^Setting parameter X to NULL disables the progress handler. 3062** ^The progress handler is also disabled by setting N to a value less 3063** than 1. 3064** 3065** ^If the progress callback returns non-zero, the operation is 3066** interrupted. This feature can be used to implement a 3067** "Cancel" button on a GUI progress dialog box. 3068** 3069** The progress handler callback must not do anything that will modify 3070** the database connection that invoked the progress handler. 3071** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3072** database connections for the meaning of "modify" in this paragraph. 3073** 3074*/ 3075void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3076 3077/* 3078** CAPI3REF: Opening A New Database Connection 3079** CONSTRUCTOR: sqlite3 3080** 3081** ^These routines open an SQLite database file as specified by the 3082** filename argument. ^The filename argument is interpreted as UTF-8 for 3083** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3084** order for sqlite3_open16(). ^(A [database connection] handle is usually 3085** returned in *ppDb, even if an error occurs. The only exception is that 3086** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3087** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3088** object.)^ ^(If the database is opened (and/or created) successfully, then 3089** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3090** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3091** an English language description of the error following a failure of any 3092** of the sqlite3_open() routines. 3093** 3094** ^The default encoding will be UTF-8 for databases created using 3095** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3096** created using sqlite3_open16() will be UTF-16 in the native byte order. 3097** 3098** Whether or not an error occurs when it is opened, resources 3099** associated with the [database connection] handle should be released by 3100** passing it to [sqlite3_close()] when it is no longer required. 3101** 3102** The sqlite3_open_v2() interface works like sqlite3_open() 3103** except that it accepts two additional parameters for additional control 3104** over the new database connection. ^(The flags parameter to 3105** sqlite3_open_v2() can take one of 3106** the following three values, optionally combined with the 3107** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3108** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3109** 3110** <dl> 3111** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3112** <dd>The database is opened in read-only mode. If the database does not 3113** already exist, an error is returned.</dd>)^ 3114** 3115** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3116** <dd>The database is opened for reading and writing if possible, or reading 3117** only if the file is write protected by the operating system. In either 3118** case the database must already exist, otherwise an error is returned.</dd>)^ 3119** 3120** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3121** <dd>The database is opened for reading and writing, and is created if 3122** it does not already exist. This is the behavior that is always used for 3123** sqlite3_open() and sqlite3_open16().</dd>)^ 3124** </dl> 3125** 3126** If the 3rd parameter to sqlite3_open_v2() is not one of the 3127** combinations shown above optionally combined with other 3128** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3129** then the behavior is undefined. 3130** 3131** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3132** opens in the multi-thread [threading mode] as long as the single-thread 3133** mode has not been set at compile-time or start-time. ^If the 3134** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3135** in the serialized [threading mode] unless single-thread was 3136** previously selected at compile-time or start-time. 3137** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3138** eligible to use [shared cache mode], regardless of whether or not shared 3139** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3140** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3141** participate in [shared cache mode] even if it is enabled. 3142** 3143** ^The fourth parameter to sqlite3_open_v2() is the name of the 3144** [sqlite3_vfs] object that defines the operating system interface that 3145** the new database connection should use. ^If the fourth parameter is 3146** a NULL pointer then the default [sqlite3_vfs] object is used. 3147** 3148** ^If the filename is ":memory:", then a private, temporary in-memory database 3149** is created for the connection. ^This in-memory database will vanish when 3150** the database connection is closed. Future versions of SQLite might 3151** make use of additional special filenames that begin with the ":" character. 3152** It is recommended that when a database filename actually does begin with 3153** a ":" character you should prefix the filename with a pathname such as 3154** "./" to avoid ambiguity. 3155** 3156** ^If the filename is an empty string, then a private, temporary 3157** on-disk database will be created. ^This private database will be 3158** automatically deleted as soon as the database connection is closed. 3159** 3160** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3161** 3162** ^If [URI filename] interpretation is enabled, and the filename argument 3163** begins with "file:", then the filename is interpreted as a URI. ^URI 3164** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3165** set in the third argument to sqlite3_open_v2(), or if it has 3166** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3167** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3168** URI filename interpretation is turned off 3169** by default, but future releases of SQLite might enable URI filename 3170** interpretation by default. See "[URI filenames]" for additional 3171** information. 3172** 3173** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3174** authority, then it must be either an empty string or the string 3175** "localhost". ^If the authority is not an empty string or "localhost", an 3176** error is returned to the caller. ^The fragment component of a URI, if 3177** present, is ignored. 3178** 3179** ^SQLite uses the path component of the URI as the name of the disk file 3180** which contains the database. ^If the path begins with a '/' character, 3181** then it is interpreted as an absolute path. ^If the path does not begin 3182** with a '/' (meaning that the authority section is omitted from the URI) 3183** then the path is interpreted as a relative path. 3184** ^(On windows, the first component of an absolute path 3185** is a drive specification (e.g. "C:").)^ 3186** 3187** [[core URI query parameters]] 3188** The query component of a URI may contain parameters that are interpreted 3189** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3190** SQLite and its built-in [VFSes] interpret the 3191** following query parameters: 3192** 3193** <ul> 3194** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3195** a VFS object that provides the operating system interface that should 3196** be used to access the database file on disk. ^If this option is set to 3197** an empty string the default VFS object is used. ^Specifying an unknown 3198** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3199** present, then the VFS specified by the option takes precedence over 3200** the value passed as the fourth parameter to sqlite3_open_v2(). 3201** 3202** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3203** "rwc", or "memory". Attempting to set it to any other value is 3204** an error)^. 3205** ^If "ro" is specified, then the database is opened for read-only 3206** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3207** third argument to sqlite3_open_v2(). ^If the mode option is set to 3208** "rw", then the database is opened for read-write (but not create) 3209** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3210** been set. ^Value "rwc" is equivalent to setting both 3211** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3212** set to "memory" then a pure [in-memory database] that never reads 3213** or writes from disk is used. ^It is an error to specify a value for 3214** the mode parameter that is less restrictive than that specified by 3215** the flags passed in the third parameter to sqlite3_open_v2(). 3216** 3217** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3218** "private". ^Setting it to "shared" is equivalent to setting the 3219** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3220** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3221** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3222** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3223** a URI filename, its value overrides any behavior requested by setting 3224** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3225** 3226** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3227** [powersafe overwrite] property does or does not apply to the 3228** storage media on which the database file resides. 3229** 3230** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3231** which if set disables file locking in rollback journal modes. This 3232** is useful for accessing a database on a filesystem that does not 3233** support locking. Caution: Database corruption might result if two 3234** or more processes write to the same database and any one of those 3235** processes uses nolock=1. 3236** 3237** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3238** parameter that indicates that the database file is stored on 3239** read-only media. ^When immutable is set, SQLite assumes that the 3240** database file cannot be changed, even by a process with higher 3241** privilege, and so the database is opened read-only and all locking 3242** and change detection is disabled. Caution: Setting the immutable 3243** property on a database file that does in fact change can result 3244** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3245** See also: [SQLITE_IOCAP_IMMUTABLE]. 3246** 3247** </ul> 3248** 3249** ^Specifying an unknown parameter in the query component of a URI is not an 3250** error. Future versions of SQLite might understand additional query 3251** parameters. See "[query parameters with special meaning to SQLite]" for 3252** additional information. 3253** 3254** [[URI filename examples]] <h3>URI filename examples</h3> 3255** 3256** <table border="1" align=center cellpadding=5> 3257** <tr><th> URI filenames <th> Results 3258** <tr><td> file:data.db <td> 3259** Open the file "data.db" in the current directory. 3260** <tr><td> file:/home/fred/data.db<br> 3261** file:///home/fred/data.db <br> 3262** file://localhost/home/fred/data.db <br> <td> 3263** Open the database file "/home/fred/data.db". 3264** <tr><td> file://darkstar/home/fred/data.db <td> 3265** An error. "darkstar" is not a recognized authority. 3266** <tr><td style="white-space:nowrap"> 3267** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3268** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3269** C:. Note that the %20 escaping in this example is not strictly 3270** necessary - space characters can be used literally 3271** in URI filenames. 3272** <tr><td> file:data.db?mode=ro&cache=private <td> 3273** Open file "data.db" in the current directory for read-only access. 3274** Regardless of whether or not shared-cache mode is enabled by 3275** default, use a private cache. 3276** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3277** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3278** that uses dot-files in place of posix advisory locking. 3279** <tr><td> file:data.db?mode=readonly <td> 3280** An error. "readonly" is not a valid option for the "mode" parameter. 3281** </table> 3282** 3283** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3284** query components of a URI. A hexadecimal escape sequence consists of a 3285** percent sign - "%" - followed by exactly two hexadecimal digits 3286** specifying an octet value. ^Before the path or query components of a 3287** URI filename are interpreted, they are encoded using UTF-8 and all 3288** hexadecimal escape sequences replaced by a single byte containing the 3289** corresponding octet. If this process generates an invalid UTF-8 encoding, 3290** the results are undefined. 3291** 3292** <b>Note to Windows users:</b> The encoding used for the filename argument 3293** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3294** codepage is currently defined. Filenames containing international 3295** characters must be converted to UTF-8 prior to passing them into 3296** sqlite3_open() or sqlite3_open_v2(). 3297** 3298** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3299** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3300** features that require the use of temporary files may fail. 3301** 3302** See also: [sqlite3_temp_directory] 3303*/ 3304int sqlite3_open( 3305 const char *filename, /* Database filename (UTF-8) */ 3306 sqlite3 **ppDb /* OUT: SQLite db handle */ 3307); 3308int sqlite3_open16( 3309 const void *filename, /* Database filename (UTF-16) */ 3310 sqlite3 **ppDb /* OUT: SQLite db handle */ 3311); 3312int sqlite3_open_v2( 3313 const char *filename, /* Database filename (UTF-8) */ 3314 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3315 int flags, /* Flags */ 3316 const char *zVfs /* Name of VFS module to use */ 3317); 3318 3319/* 3320** CAPI3REF: Obtain Values For URI Parameters 3321** 3322** These are utility routines, useful to VFS implementations, that check 3323** to see if a database file was a URI that contained a specific query 3324** parameter, and if so obtains the value of that query parameter. 3325** 3326** If F is the database filename pointer passed into the xOpen() method of 3327** a VFS implementation when the flags parameter to xOpen() has one or 3328** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3329** P is the name of the query parameter, then 3330** sqlite3_uri_parameter(F,P) returns the value of the P 3331** parameter if it exists or a NULL pointer if P does not appear as a 3332** query parameter on F. If P is a query parameter of F 3333** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3334** a pointer to an empty string. 3335** 3336** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3337** parameter and returns true (1) or false (0) according to the value 3338** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3339** value of query parameter P is one of "yes", "true", or "on" in any 3340** case or if the value begins with a non-zero number. The 3341** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3342** query parameter P is one of "no", "false", or "off" in any case or 3343** if the value begins with a numeric zero. If P is not a query 3344** parameter on F or if the value of P is does not match any of the 3345** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3346** 3347** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3348** 64-bit signed integer and returns that integer, or D if P does not 3349** exist. If the value of P is something other than an integer, then 3350** zero is returned. 3351** 3352** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3353** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3354** is not a database file pathname pointer that SQLite passed into the xOpen 3355** VFS method, then the behavior of this routine is undefined and probably 3356** undesirable. 3357*/ 3358const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3359int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3360sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3361 3362 3363/* 3364** CAPI3REF: Error Codes And Messages 3365** METHOD: sqlite3 3366** 3367** ^If the most recent sqlite3_* API call associated with 3368** [database connection] D failed, then the sqlite3_errcode(D) interface 3369** returns the numeric [result code] or [extended result code] for that 3370** API call. 3371** If the most recent API call was successful, 3372** then the return value from sqlite3_errcode() is undefined. 3373** ^The sqlite3_extended_errcode() 3374** interface is the same except that it always returns the 3375** [extended result code] even when extended result codes are 3376** disabled. 3377** 3378** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3379** text that describes the error, as either UTF-8 or UTF-16 respectively. 3380** ^(Memory to hold the error message string is managed internally. 3381** The application does not need to worry about freeing the result. 3382** However, the error string might be overwritten or deallocated by 3383** subsequent calls to other SQLite interface functions.)^ 3384** 3385** ^The sqlite3_errstr() interface returns the English-language text 3386** that describes the [result code], as UTF-8. 3387** ^(Memory to hold the error message string is managed internally 3388** and must not be freed by the application)^. 3389** 3390** When the serialized [threading mode] is in use, it might be the 3391** case that a second error occurs on a separate thread in between 3392** the time of the first error and the call to these interfaces. 3393** When that happens, the second error will be reported since these 3394** interfaces always report the most recent result. To avoid 3395** this, each thread can obtain exclusive use of the [database connection] D 3396** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3397** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3398** all calls to the interfaces listed here are completed. 3399** 3400** If an interface fails with SQLITE_MISUSE, that means the interface 3401** was invoked incorrectly by the application. In that case, the 3402** error code and message may or may not be set. 3403*/ 3404int sqlite3_errcode(sqlite3 *db); 3405int sqlite3_extended_errcode(sqlite3 *db); 3406const char *sqlite3_errmsg(sqlite3*); 3407const void *sqlite3_errmsg16(sqlite3*); 3408const char *sqlite3_errstr(int); 3409 3410/* 3411** CAPI3REF: Prepared Statement Object 3412** KEYWORDS: {prepared statement} {prepared statements} 3413** 3414** An instance of this object represents a single SQL statement that 3415** has been compiled into binary form and is ready to be evaluated. 3416** 3417** Think of each SQL statement as a separate computer program. The 3418** original SQL text is source code. A prepared statement object 3419** is the compiled object code. All SQL must be converted into a 3420** prepared statement before it can be run. 3421** 3422** The life-cycle of a prepared statement object usually goes like this: 3423** 3424** <ol> 3425** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3426** <li> Bind values to [parameters] using the sqlite3_bind_*() 3427** interfaces. 3428** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3429** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3430** to step 2. Do this zero or more times. 3431** <li> Destroy the object using [sqlite3_finalize()]. 3432** </ol> 3433*/ 3434typedef struct sqlite3_stmt sqlite3_stmt; 3435 3436/* 3437** CAPI3REF: Run-time Limits 3438** METHOD: sqlite3 3439** 3440** ^(This interface allows the size of various constructs to be limited 3441** on a connection by connection basis. The first parameter is the 3442** [database connection] whose limit is to be set or queried. The 3443** second parameter is one of the [limit categories] that define a 3444** class of constructs to be size limited. The third parameter is the 3445** new limit for that construct.)^ 3446** 3447** ^If the new limit is a negative number, the limit is unchanged. 3448** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3449** [limits | hard upper bound] 3450** set at compile-time by a C preprocessor macro called 3451** [limits | SQLITE_MAX_<i>NAME</i>]. 3452** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3453** ^Attempts to increase a limit above its hard upper bound are 3454** silently truncated to the hard upper bound. 3455** 3456** ^Regardless of whether or not the limit was changed, the 3457** [sqlite3_limit()] interface returns the prior value of the limit. 3458** ^Hence, to find the current value of a limit without changing it, 3459** simply invoke this interface with the third parameter set to -1. 3460** 3461** Run-time limits are intended for use in applications that manage 3462** both their own internal database and also databases that are controlled 3463** by untrusted external sources. An example application might be a 3464** web browser that has its own databases for storing history and 3465** separate databases controlled by JavaScript applications downloaded 3466** off the Internet. The internal databases can be given the 3467** large, default limits. Databases managed by external sources can 3468** be given much smaller limits designed to prevent a denial of service 3469** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3470** interface to further control untrusted SQL. The size of the database 3471** created by an untrusted script can be contained using the 3472** [max_page_count] [PRAGMA]. 3473** 3474** New run-time limit categories may be added in future releases. 3475*/ 3476int sqlite3_limit(sqlite3*, int id, int newVal); 3477 3478/* 3479** CAPI3REF: Run-Time Limit Categories 3480** KEYWORDS: {limit category} {*limit categories} 3481** 3482** These constants define various performance limits 3483** that can be lowered at run-time using [sqlite3_limit()]. 3484** The synopsis of the meanings of the various limits is shown below. 3485** Additional information is available at [limits | Limits in SQLite]. 3486** 3487** <dl> 3488** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3489** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3490** 3491** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3492** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3493** 3494** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3495** <dd>The maximum number of columns in a table definition or in the 3496** result set of a [SELECT] or the maximum number of columns in an index 3497** or in an ORDER BY or GROUP BY clause.</dd>)^ 3498** 3499** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3500** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3501** 3502** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3503** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3504** 3505** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3506** <dd>The maximum number of instructions in a virtual machine program 3507** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3508** the equivalent tries to allocate space for more than this many opcodes 3509** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3510** 3511** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3512** <dd>The maximum number of arguments on a function.</dd>)^ 3513** 3514** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3515** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3516** 3517** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3518** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3519** <dd>The maximum length of the pattern argument to the [LIKE] or 3520** [GLOB] operators.</dd>)^ 3521** 3522** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3523** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3524** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3525** 3526** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3527** <dd>The maximum depth of recursion for triggers.</dd>)^ 3528** 3529** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3530** <dd>The maximum number of auxiliary worker threads that a single 3531** [prepared statement] may start.</dd>)^ 3532** </dl> 3533*/ 3534#define SQLITE_LIMIT_LENGTH 0 3535#define SQLITE_LIMIT_SQL_LENGTH 1 3536#define SQLITE_LIMIT_COLUMN 2 3537#define SQLITE_LIMIT_EXPR_DEPTH 3 3538#define SQLITE_LIMIT_COMPOUND_SELECT 4 3539#define SQLITE_LIMIT_VDBE_OP 5 3540#define SQLITE_LIMIT_FUNCTION_ARG 6 3541#define SQLITE_LIMIT_ATTACHED 7 3542#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3543#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3544#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3545#define SQLITE_LIMIT_WORKER_THREADS 11 3546 3547/* 3548** CAPI3REF: Prepare Flags 3549** 3550** These constants define various flags that can be passed into 3551** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3552** [sqlite3_prepare16_v3()] interfaces. 3553** 3554** New flags may be added in future releases of SQLite. 3555** 3556** <dl> 3557** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3558** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3559** that the prepared statement will be retained for a long time and 3560** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3561** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3562** be used just once or at most a few times and then destroyed using 3563** [sqlite3_finalize()] relatively soon. The current implementation acts 3564** on this hint by avoiding the use of [lookaside memory] so as not to 3565** deplete the limited store of lookaside memory. Future versions of 3566** SQLite may act on this hint differently. 3567** </dl> 3568*/ 3569#define SQLITE_PREPARE_PERSISTENT 0x01 3570 3571/* 3572** CAPI3REF: Compiling An SQL Statement 3573** KEYWORDS: {SQL statement compiler} 3574** METHOD: sqlite3 3575** CONSTRUCTOR: sqlite3_stmt 3576** 3577** To execute an SQL statement, it must first be compiled into a byte-code 3578** program using one of these routines. Or, in other words, these routines 3579** are constructors for the [prepared statement] object. 3580** 3581** The preferred routine to use is [sqlite3_prepare_v2()]. The 3582** [sqlite3_prepare()] interface is legacy and should be avoided. 3583** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3584** for special purposes. 3585** 3586** The use of the UTF-8 interfaces is preferred, as SQLite currently 3587** does all parsing using UTF-8. The UTF-16 interfaces are provided 3588** as a convenience. The UTF-16 interfaces work by converting the 3589** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3590** 3591** The first argument, "db", is a [database connection] obtained from a 3592** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3593** [sqlite3_open16()]. The database connection must not have been closed. 3594** 3595** The second argument, "zSql", is the statement to be compiled, encoded 3596** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3597** and sqlite3_prepare_v3() 3598** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3599** and sqlite3_prepare16_v3() use UTF-16. 3600** 3601** ^If the nByte argument is negative, then zSql is read up to the 3602** first zero terminator. ^If nByte is positive, then it is the 3603** number of bytes read from zSql. ^If nByte is zero, then no prepared 3604** statement is generated. 3605** If the caller knows that the supplied string is nul-terminated, then 3606** there is a small performance advantage to passing an nByte parameter that 3607** is the number of bytes in the input string <i>including</i> 3608** the nul-terminator. 3609** 3610** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3611** past the end of the first SQL statement in zSql. These routines only 3612** compile the first statement in zSql, so *pzTail is left pointing to 3613** what remains uncompiled. 3614** 3615** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3616** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3617** to NULL. ^If the input text contains no SQL (if the input is an empty 3618** string or a comment) then *ppStmt is set to NULL. 3619** The calling procedure is responsible for deleting the compiled 3620** SQL statement using [sqlite3_finalize()] after it has finished with it. 3621** ppStmt may not be NULL. 3622** 3623** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3624** otherwise an [error code] is returned. 3625** 3626** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3627** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3628** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3629** are retained for backwards compatibility, but their use is discouraged. 3630** ^In the "vX" interfaces, the prepared statement 3631** that is returned (the [sqlite3_stmt] object) contains a copy of the 3632** original SQL text. This causes the [sqlite3_step()] interface to 3633** behave differently in three ways: 3634** 3635** <ol> 3636** <li> 3637** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3638** always used to do, [sqlite3_step()] will automatically recompile the SQL 3639** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3640** retries will occur before sqlite3_step() gives up and returns an error. 3641** </li> 3642** 3643** <li> 3644** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3645** [error codes] or [extended error codes]. ^The legacy behavior was that 3646** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3647** and the application would have to make a second call to [sqlite3_reset()] 3648** in order to find the underlying cause of the problem. With the "v2" prepare 3649** interfaces, the underlying reason for the error is returned immediately. 3650** </li> 3651** 3652** <li> 3653** ^If the specific value bound to [parameter | host parameter] in the 3654** WHERE clause might influence the choice of query plan for a statement, 3655** then the statement will be automatically recompiled, as if there had been 3656** a schema change, on the first [sqlite3_step()] call following any change 3657** to the [sqlite3_bind_text | bindings] of that [parameter]. 3658** ^The specific value of WHERE-clause [parameter] might influence the 3659** choice of query plan if the parameter is the left-hand side of a [LIKE] 3660** or [GLOB] operator or if the parameter is compared to an indexed column 3661** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3662** </li> 3663** 3664** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3665** the extra prepFlags parameter, which is a bit array consisting of zero or 3666** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3667** sqlite3_prepare_v2() interface works exactly the same as 3668** sqlite3_prepare_v3() with a zero prepFlags parameter. 3669** </ol> 3670*/ 3671int sqlite3_prepare( 3672 sqlite3 *db, /* Database handle */ 3673 const char *zSql, /* SQL statement, UTF-8 encoded */ 3674 int nByte, /* Maximum length of zSql in bytes. */ 3675 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3676 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3677); 3678int sqlite3_prepare_v2( 3679 sqlite3 *db, /* Database handle */ 3680 const char *zSql, /* SQL statement, UTF-8 encoded */ 3681 int nByte, /* Maximum length of zSql in bytes. */ 3682 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3683 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3684); 3685int sqlite3_prepare_v3( 3686 sqlite3 *db, /* Database handle */ 3687 const char *zSql, /* SQL statement, UTF-8 encoded */ 3688 int nByte, /* Maximum length of zSql in bytes. */ 3689 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3690 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3691 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3692); 3693int sqlite3_prepare16( 3694 sqlite3 *db, /* Database handle */ 3695 const void *zSql, /* SQL statement, UTF-16 encoded */ 3696 int nByte, /* Maximum length of zSql in bytes. */ 3697 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3698 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3699); 3700int sqlite3_prepare16_v2( 3701 sqlite3 *db, /* Database handle */ 3702 const void *zSql, /* SQL statement, UTF-16 encoded */ 3703 int nByte, /* Maximum length of zSql in bytes. */ 3704 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3705 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3706); 3707int sqlite3_prepare16_v3( 3708 sqlite3 *db, /* Database handle */ 3709 const void *zSql, /* SQL statement, UTF-16 encoded */ 3710 int nByte, /* Maximum length of zSql in bytes. */ 3711 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3712 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3713 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3714); 3715 3716/* 3717** CAPI3REF: Retrieving Statement SQL 3718** METHOD: sqlite3_stmt 3719** 3720** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3721** SQL text used to create [prepared statement] P if P was 3722** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3723** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3724** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3725** string containing the SQL text of prepared statement P with 3726** [bound parameters] expanded. 3727** 3728** ^(For example, if a prepared statement is created using the SQL 3729** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3730** and parameter :xyz is unbound, then sqlite3_sql() will return 3731** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3732** will return "SELECT 2345,NULL".)^ 3733** 3734** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3735** is available to hold the result, or if the result would exceed the 3736** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3737** 3738** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3739** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3740** option causes sqlite3_expanded_sql() to always return NULL. 3741** 3742** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3743** automatically freed when the prepared statement is finalized. 3744** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3745** is obtained from [sqlite3_malloc()] and must be free by the application 3746** by passing it to [sqlite3_free()]. 3747*/ 3748const char *sqlite3_sql(sqlite3_stmt *pStmt); 3749char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3750 3751/* 3752** CAPI3REF: Determine If An SQL Statement Writes The Database 3753** METHOD: sqlite3_stmt 3754** 3755** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3756** and only if the [prepared statement] X makes no direct changes to 3757** the content of the database file. 3758** 3759** Note that [application-defined SQL functions] or 3760** [virtual tables] might change the database indirectly as a side effect. 3761** ^(For example, if an application defines a function "eval()" that 3762** calls [sqlite3_exec()], then the following SQL statement would 3763** change the database file through side-effects: 3764** 3765** <blockquote><pre> 3766** SELECT eval('DELETE FROM t1') FROM t2; 3767** </pre></blockquote> 3768** 3769** But because the [SELECT] statement does not change the database file 3770** directly, sqlite3_stmt_readonly() would still return true.)^ 3771** 3772** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3773** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3774** since the statements themselves do not actually modify the database but 3775** rather they control the timing of when other statements modify the 3776** database. ^The [ATTACH] and [DETACH] statements also cause 3777** sqlite3_stmt_readonly() to return true since, while those statements 3778** change the configuration of a database connection, they do not make 3779** changes to the content of the database files on disk. 3780** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3781** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3782** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3783** sqlite3_stmt_readonly() returns false for those commands. 3784*/ 3785int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3786 3787/* 3788** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3789** METHOD: sqlite3_stmt 3790** 3791** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3792** [prepared statement] S has been stepped at least once using 3793** [sqlite3_step(S)] but has neither run to completion (returned 3794** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3795** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3796** interface returns false if S is a NULL pointer. If S is not a 3797** NULL pointer and is not a pointer to a valid [prepared statement] 3798** object, then the behavior is undefined and probably undesirable. 3799** 3800** This interface can be used in combination [sqlite3_next_stmt()] 3801** to locate all prepared statements associated with a database 3802** connection that are in need of being reset. This can be used, 3803** for example, in diagnostic routines to search for prepared 3804** statements that are holding a transaction open. 3805*/ 3806int sqlite3_stmt_busy(sqlite3_stmt*); 3807 3808/* 3809** CAPI3REF: Dynamically Typed Value Object 3810** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3811** 3812** SQLite uses the sqlite3_value object to represent all values 3813** that can be stored in a database table. SQLite uses dynamic typing 3814** for the values it stores. ^Values stored in sqlite3_value objects 3815** can be integers, floating point values, strings, BLOBs, or NULL. 3816** 3817** An sqlite3_value object may be either "protected" or "unprotected". 3818** Some interfaces require a protected sqlite3_value. Other interfaces 3819** will accept either a protected or an unprotected sqlite3_value. 3820** Every interface that accepts sqlite3_value arguments specifies 3821** whether or not it requires a protected sqlite3_value. The 3822** [sqlite3_value_dup()] interface can be used to construct a new 3823** protected sqlite3_value from an unprotected sqlite3_value. 3824** 3825** The terms "protected" and "unprotected" refer to whether or not 3826** a mutex is held. An internal mutex is held for a protected 3827** sqlite3_value object but no mutex is held for an unprotected 3828** sqlite3_value object. If SQLite is compiled to be single-threaded 3829** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3830** or if SQLite is run in one of reduced mutex modes 3831** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3832** then there is no distinction between protected and unprotected 3833** sqlite3_value objects and they can be used interchangeably. However, 3834** for maximum code portability it is recommended that applications 3835** still make the distinction between protected and unprotected 3836** sqlite3_value objects even when not strictly required. 3837** 3838** ^The sqlite3_value objects that are passed as parameters into the 3839** implementation of [application-defined SQL functions] are protected. 3840** ^The sqlite3_value object returned by 3841** [sqlite3_column_value()] is unprotected. 3842** Unprotected sqlite3_value objects may only be used as arguments 3843** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3844** [sqlite3_value_dup()]. 3845** The [sqlite3_value_blob | sqlite3_value_type()] family of 3846** interfaces require protected sqlite3_value objects. 3847*/ 3848typedef struct sqlite3_value sqlite3_value; 3849 3850/* 3851** CAPI3REF: SQL Function Context Object 3852** 3853** The context in which an SQL function executes is stored in an 3854** sqlite3_context object. ^A pointer to an sqlite3_context object 3855** is always first parameter to [application-defined SQL functions]. 3856** The application-defined SQL function implementation will pass this 3857** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3858** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3859** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3860** and/or [sqlite3_set_auxdata()]. 3861*/ 3862typedef struct sqlite3_context sqlite3_context; 3863 3864/* 3865** CAPI3REF: Binding Values To Prepared Statements 3866** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3867** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3868** METHOD: sqlite3_stmt 3869** 3870** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3871** literals may be replaced by a [parameter] that matches one of following 3872** templates: 3873** 3874** <ul> 3875** <li> ? 3876** <li> ?NNN 3877** <li> :VVV 3878** <li> @VVV 3879** <li> $VVV 3880** </ul> 3881** 3882** In the templates above, NNN represents an integer literal, 3883** and VVV represents an alphanumeric identifier.)^ ^The values of these 3884** parameters (also called "host parameter names" or "SQL parameters") 3885** can be set using the sqlite3_bind_*() routines defined here. 3886** 3887** ^The first argument to the sqlite3_bind_*() routines is always 3888** a pointer to the [sqlite3_stmt] object returned from 3889** [sqlite3_prepare_v2()] or its variants. 3890** 3891** ^The second argument is the index of the SQL parameter to be set. 3892** ^The leftmost SQL parameter has an index of 1. ^When the same named 3893** SQL parameter is used more than once, second and subsequent 3894** occurrences have the same index as the first occurrence. 3895** ^The index for named parameters can be looked up using the 3896** [sqlite3_bind_parameter_index()] API if desired. ^The index 3897** for "?NNN" parameters is the value of NNN. 3898** ^The NNN value must be between 1 and the [sqlite3_limit()] 3899** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3900** 3901** ^The third argument is the value to bind to the parameter. 3902** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3903** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3904** is ignored and the end result is the same as sqlite3_bind_null(). 3905** 3906** ^(In those routines that have a fourth argument, its value is the 3907** number of bytes in the parameter. To be clear: the value is the 3908** number of <u>bytes</u> in the value, not the number of characters.)^ 3909** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3910** is negative, then the length of the string is 3911** the number of bytes up to the first zero terminator. 3912** If the fourth parameter to sqlite3_bind_blob() is negative, then 3913** the behavior is undefined. 3914** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3915** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3916** that parameter must be the byte offset 3917** where the NUL terminator would occur assuming the string were NUL 3918** terminated. If any NUL characters occur at byte offsets less than 3919** the value of the fourth parameter then the resulting string value will 3920** contain embedded NULs. The result of expressions involving strings 3921** with embedded NULs is undefined. 3922** 3923** ^The fifth argument to the BLOB and string binding interfaces 3924** is a destructor used to dispose of the BLOB or 3925** string after SQLite has finished with it. ^The destructor is called 3926** to dispose of the BLOB or string even if the call to bind API fails. 3927** ^If the fifth argument is 3928** the special value [SQLITE_STATIC], then SQLite assumes that the 3929** information is in static, unmanaged space and does not need to be freed. 3930** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3931** SQLite makes its own private copy of the data immediately, before 3932** the sqlite3_bind_*() routine returns. 3933** 3934** ^The sixth argument to sqlite3_bind_text64() must be one of 3935** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3936** to specify the encoding of the text in the third parameter. If 3937** the sixth argument to sqlite3_bind_text64() is not one of the 3938** allowed values shown above, or if the text encoding is different 3939** from the encoding specified by the sixth parameter, then the behavior 3940** is undefined. 3941** 3942** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3943** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3944** (just an integer to hold its size) while it is being processed. 3945** Zeroblobs are intended to serve as placeholders for BLOBs whose 3946** content is later written using 3947** [sqlite3_blob_open | incremental BLOB I/O] routines. 3948** ^A negative value for the zeroblob results in a zero-length BLOB. 3949** 3950** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3951** [prepared statement] S to have an SQL value of NULL, but to also be 3952** associated with the pointer P of type T. ^D is either a NULL pointer or 3953** a pointer to a destructor function for P. ^SQLite will invoke the 3954** destructor D with a single argument of P when it is finished using 3955** P. The T parameter should be a static string, preferably a string 3956** literal. The sqlite3_bind_pointer() routine is part of the 3957** [pointer passing interface] added for SQLite 3.20.0. 3958** 3959** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3960** for the [prepared statement] or with a prepared statement for which 3961** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3962** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3963** routine is passed a [prepared statement] that has been finalized, the 3964** result is undefined and probably harmful. 3965** 3966** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3967** ^Unbound parameters are interpreted as NULL. 3968** 3969** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3970** [error code] if anything goes wrong. 3971** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3972** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3973** [SQLITE_MAX_LENGTH]. 3974** ^[SQLITE_RANGE] is returned if the parameter 3975** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3976** 3977** See also: [sqlite3_bind_parameter_count()], 3978** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3979*/ 3980int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3981int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3982 void(*)(void*)); 3983int sqlite3_bind_double(sqlite3_stmt*, int, double); 3984int sqlite3_bind_int(sqlite3_stmt*, int, int); 3985int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3986int sqlite3_bind_null(sqlite3_stmt*, int); 3987int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3988int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3989int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3990 void(*)(void*), unsigned char encoding); 3991int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3992int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3993int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3994int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3995 3996/* 3997** CAPI3REF: Number Of SQL Parameters 3998** METHOD: sqlite3_stmt 3999** 4000** ^This routine can be used to find the number of [SQL parameters] 4001** in a [prepared statement]. SQL parameters are tokens of the 4002** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4003** placeholders for values that are [sqlite3_bind_blob | bound] 4004** to the parameters at a later time. 4005** 4006** ^(This routine actually returns the index of the largest (rightmost) 4007** parameter. For all forms except ?NNN, this will correspond to the 4008** number of unique parameters. If parameters of the ?NNN form are used, 4009** there may be gaps in the list.)^ 4010** 4011** See also: [sqlite3_bind_blob|sqlite3_bind()], 4012** [sqlite3_bind_parameter_name()], and 4013** [sqlite3_bind_parameter_index()]. 4014*/ 4015int sqlite3_bind_parameter_count(sqlite3_stmt*); 4016 4017/* 4018** CAPI3REF: Name Of A Host Parameter 4019** METHOD: sqlite3_stmt 4020** 4021** ^The sqlite3_bind_parameter_name(P,N) interface returns 4022** the name of the N-th [SQL parameter] in the [prepared statement] P. 4023** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4024** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4025** respectively. 4026** In other words, the initial ":" or "$" or "@" or "?" 4027** is included as part of the name.)^ 4028** ^Parameters of the form "?" without a following integer have no name 4029** and are referred to as "nameless" or "anonymous parameters". 4030** 4031** ^The first host parameter has an index of 1, not 0. 4032** 4033** ^If the value N is out of range or if the N-th parameter is 4034** nameless, then NULL is returned. ^The returned string is 4035** always in UTF-8 encoding even if the named parameter was 4036** originally specified as UTF-16 in [sqlite3_prepare16()], 4037** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4038** 4039** See also: [sqlite3_bind_blob|sqlite3_bind()], 4040** [sqlite3_bind_parameter_count()], and 4041** [sqlite3_bind_parameter_index()]. 4042*/ 4043const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4044 4045/* 4046** CAPI3REF: Index Of A Parameter With A Given Name 4047** METHOD: sqlite3_stmt 4048** 4049** ^Return the index of an SQL parameter given its name. ^The 4050** index value returned is suitable for use as the second 4051** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4052** is returned if no matching parameter is found. ^The parameter 4053** name must be given in UTF-8 even if the original statement 4054** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4055** [sqlite3_prepare16_v3()]. 4056** 4057** See also: [sqlite3_bind_blob|sqlite3_bind()], 4058** [sqlite3_bind_parameter_count()], and 4059** [sqlite3_bind_parameter_name()]. 4060*/ 4061int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4062 4063/* 4064** CAPI3REF: Reset All Bindings On A Prepared Statement 4065** METHOD: sqlite3_stmt 4066** 4067** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4068** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4069** ^Use this routine to reset all host parameters to NULL. 4070*/ 4071int sqlite3_clear_bindings(sqlite3_stmt*); 4072 4073/* 4074** CAPI3REF: Number Of Columns In A Result Set 4075** METHOD: sqlite3_stmt 4076** 4077** ^Return the number of columns in the result set returned by the 4078** [prepared statement]. ^If this routine returns 0, that means the 4079** [prepared statement] returns no data (for example an [UPDATE]). 4080** ^However, just because this routine returns a positive number does not 4081** mean that one or more rows of data will be returned. ^A SELECT statement 4082** will always have a positive sqlite3_column_count() but depending on the 4083** WHERE clause constraints and the table content, it might return no rows. 4084** 4085** See also: [sqlite3_data_count()] 4086*/ 4087int sqlite3_column_count(sqlite3_stmt *pStmt); 4088 4089/* 4090** CAPI3REF: Column Names In A Result Set 4091** METHOD: sqlite3_stmt 4092** 4093** ^These routines return the name assigned to a particular column 4094** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4095** interface returns a pointer to a zero-terminated UTF-8 string 4096** and sqlite3_column_name16() returns a pointer to a zero-terminated 4097** UTF-16 string. ^The first parameter is the [prepared statement] 4098** that implements the [SELECT] statement. ^The second parameter is the 4099** column number. ^The leftmost column is number 0. 4100** 4101** ^The returned string pointer is valid until either the [prepared statement] 4102** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4103** reprepared by the first call to [sqlite3_step()] for a particular run 4104** or until the next call to 4105** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4106** 4107** ^If sqlite3_malloc() fails during the processing of either routine 4108** (for example during a conversion from UTF-8 to UTF-16) then a 4109** NULL pointer is returned. 4110** 4111** ^The name of a result column is the value of the "AS" clause for 4112** that column, if there is an AS clause. If there is no AS clause 4113** then the name of the column is unspecified and may change from 4114** one release of SQLite to the next. 4115*/ 4116const char *sqlite3_column_name(sqlite3_stmt*, int N); 4117const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4118 4119/* 4120** CAPI3REF: Source Of Data In A Query Result 4121** METHOD: sqlite3_stmt 4122** 4123** ^These routines provide a means to determine the database, table, and 4124** table column that is the origin of a particular result column in 4125** [SELECT] statement. 4126** ^The name of the database or table or column can be returned as 4127** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4128** the database name, the _table_ routines return the table name, and 4129** the origin_ routines return the column name. 4130** ^The returned string is valid until the [prepared statement] is destroyed 4131** using [sqlite3_finalize()] or until the statement is automatically 4132** reprepared by the first call to [sqlite3_step()] for a particular run 4133** or until the same information is requested 4134** again in a different encoding. 4135** 4136** ^The names returned are the original un-aliased names of the 4137** database, table, and column. 4138** 4139** ^The first argument to these interfaces is a [prepared statement]. 4140** ^These functions return information about the Nth result column returned by 4141** the statement, where N is the second function argument. 4142** ^The left-most column is column 0 for these routines. 4143** 4144** ^If the Nth column returned by the statement is an expression or 4145** subquery and is not a column value, then all of these functions return 4146** NULL. ^These routine might also return NULL if a memory allocation error 4147** occurs. ^Otherwise, they return the name of the attached database, table, 4148** or column that query result column was extracted from. 4149** 4150** ^As with all other SQLite APIs, those whose names end with "16" return 4151** UTF-16 encoded strings and the other functions return UTF-8. 4152** 4153** ^These APIs are only available if the library was compiled with the 4154** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4155** 4156** If two or more threads call one or more of these routines against the same 4157** prepared statement and column at the same time then the results are 4158** undefined. 4159** 4160** If two or more threads call one or more 4161** [sqlite3_column_database_name | column metadata interfaces] 4162** for the same [prepared statement] and result column 4163** at the same time then the results are undefined. 4164*/ 4165const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4166const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4167const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4168const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4169const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4170const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4171 4172/* 4173** CAPI3REF: Declared Datatype Of A Query Result 4174** METHOD: sqlite3_stmt 4175** 4176** ^(The first parameter is a [prepared statement]. 4177** If this statement is a [SELECT] statement and the Nth column of the 4178** returned result set of that [SELECT] is a table column (not an 4179** expression or subquery) then the declared type of the table 4180** column is returned.)^ ^If the Nth column of the result set is an 4181** expression or subquery, then a NULL pointer is returned. 4182** ^The returned string is always UTF-8 encoded. 4183** 4184** ^(For example, given the database schema: 4185** 4186** CREATE TABLE t1(c1 VARIANT); 4187** 4188** and the following statement to be compiled: 4189** 4190** SELECT c1 + 1, c1 FROM t1; 4191** 4192** this routine would return the string "VARIANT" for the second result 4193** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4194** 4195** ^SQLite uses dynamic run-time typing. ^So just because a column 4196** is declared to contain a particular type does not mean that the 4197** data stored in that column is of the declared type. SQLite is 4198** strongly typed, but the typing is dynamic not static. ^Type 4199** is associated with individual values, not with the containers 4200** used to hold those values. 4201*/ 4202const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4203const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4204 4205/* 4206** CAPI3REF: Evaluate An SQL Statement 4207** METHOD: sqlite3_stmt 4208** 4209** After a [prepared statement] has been prepared using any of 4210** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4211** or [sqlite3_prepare16_v3()] or one of the legacy 4212** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4213** must be called one or more times to evaluate the statement. 4214** 4215** The details of the behavior of the sqlite3_step() interface depend 4216** on whether the statement was prepared using the newer "vX" interfaces 4217** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4218** [sqlite3_prepare16_v2()] or the older legacy 4219** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4220** new "vX" interface is recommended for new applications but the legacy 4221** interface will continue to be supported. 4222** 4223** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4224** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4225** ^With the "v2" interface, any of the other [result codes] or 4226** [extended result codes] might be returned as well. 4227** 4228** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4229** database locks it needs to do its job. ^If the statement is a [COMMIT] 4230** or occurs outside of an explicit transaction, then you can retry the 4231** statement. If the statement is not a [COMMIT] and occurs within an 4232** explicit transaction then you should rollback the transaction before 4233** continuing. 4234** 4235** ^[SQLITE_DONE] means that the statement has finished executing 4236** successfully. sqlite3_step() should not be called again on this virtual 4237** machine without first calling [sqlite3_reset()] to reset the virtual 4238** machine back to its initial state. 4239** 4240** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4241** is returned each time a new row of data is ready for processing by the 4242** caller. The values may be accessed using the [column access functions]. 4243** sqlite3_step() is called again to retrieve the next row of data. 4244** 4245** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4246** violation) has occurred. sqlite3_step() should not be called again on 4247** the VM. More information may be found by calling [sqlite3_errmsg()]. 4248** ^With the legacy interface, a more specific error code (for example, 4249** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4250** can be obtained by calling [sqlite3_reset()] on the 4251** [prepared statement]. ^In the "v2" interface, 4252** the more specific error code is returned directly by sqlite3_step(). 4253** 4254** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4255** Perhaps it was called on a [prepared statement] that has 4256** already been [sqlite3_finalize | finalized] or on one that had 4257** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4258** be the case that the same database connection is being used by two or 4259** more threads at the same moment in time. 4260** 4261** For all versions of SQLite up to and including 3.6.23.1, a call to 4262** [sqlite3_reset()] was required after sqlite3_step() returned anything 4263** other than [SQLITE_ROW] before any subsequent invocation of 4264** sqlite3_step(). Failure to reset the prepared statement using 4265** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4266** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4267** sqlite3_step() began 4268** calling [sqlite3_reset()] automatically in this circumstance rather 4269** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4270** break because any application that ever receives an SQLITE_MISUSE error 4271** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4272** can be used to restore the legacy behavior. 4273** 4274** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4275** API always returns a generic error code, [SQLITE_ERROR], following any 4276** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4277** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4278** specific [error codes] that better describes the error. 4279** We admit that this is a goofy design. The problem has been fixed 4280** with the "v2" interface. If you prepare all of your SQL statements 4281** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4282** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4283** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4284** then the more specific [error codes] are returned directly 4285** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4286*/ 4287int sqlite3_step(sqlite3_stmt*); 4288 4289/* 4290** CAPI3REF: Number of columns in a result set 4291** METHOD: sqlite3_stmt 4292** 4293** ^The sqlite3_data_count(P) interface returns the number of columns in the 4294** current row of the result set of [prepared statement] P. 4295** ^If prepared statement P does not have results ready to return 4296** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4297** interfaces) then sqlite3_data_count(P) returns 0. 4298** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4299** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4300** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4301** will return non-zero if previous call to [sqlite3_step](P) returned 4302** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4303** where it always returns zero since each step of that multi-step 4304** pragma returns 0 columns of data. 4305** 4306** See also: [sqlite3_column_count()] 4307*/ 4308int sqlite3_data_count(sqlite3_stmt *pStmt); 4309 4310/* 4311** CAPI3REF: Fundamental Datatypes 4312** KEYWORDS: SQLITE_TEXT 4313** 4314** ^(Every value in SQLite has one of five fundamental datatypes: 4315** 4316** <ul> 4317** <li> 64-bit signed integer 4318** <li> 64-bit IEEE floating point number 4319** <li> string 4320** <li> BLOB 4321** <li> NULL 4322** </ul>)^ 4323** 4324** These constants are codes for each of those types. 4325** 4326** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4327** for a completely different meaning. Software that links against both 4328** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4329** SQLITE_TEXT. 4330*/ 4331#define SQLITE_INTEGER 1 4332#define SQLITE_FLOAT 2 4333#define SQLITE_BLOB 4 4334#define SQLITE_NULL 5 4335#ifdef SQLITE_TEXT 4336# undef SQLITE_TEXT 4337#else 4338# define SQLITE_TEXT 3 4339#endif 4340#define SQLITE3_TEXT 3 4341 4342/* 4343** CAPI3REF: Result Values From A Query 4344** KEYWORDS: {column access functions} 4345** METHOD: sqlite3_stmt 4346** 4347** <b>Summary:</b> 4348** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4349** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4350** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4351** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4352** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4353** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4354** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4355** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4356** [sqlite3_value|unprotected sqlite3_value] object. 4357** <tr><td> <td> <td> 4358** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4359** or a UTF-8 TEXT result in bytes 4360** <tr><td><b>sqlite3_column_bytes16 </b> 4361** <td>→ <td>Size of UTF-16 4362** TEXT in bytes 4363** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4364** datatype of the result 4365** </table></blockquote> 4366** 4367** <b>Details:</b> 4368** 4369** ^These routines return information about a single column of the current 4370** result row of a query. ^In every case the first argument is a pointer 4371** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4372** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4373** and the second argument is the index of the column for which information 4374** should be returned. ^The leftmost column of the result set has the index 0. 4375** ^The number of columns in the result can be determined using 4376** [sqlite3_column_count()]. 4377** 4378** If the SQL statement does not currently point to a valid row, or if the 4379** column index is out of range, the result is undefined. 4380** These routines may only be called when the most recent call to 4381** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4382** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4383** If any of these routines are called after [sqlite3_reset()] or 4384** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4385** something other than [SQLITE_ROW], the results are undefined. 4386** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4387** are called from a different thread while any of these routines 4388** are pending, then the results are undefined. 4389** 4390** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4391** each return the value of a result column in a specific data format. If 4392** the result column is not initially in the requested format (for example, 4393** if the query returns an integer but the sqlite3_column_text() interface 4394** is used to extract the value) then an automatic type conversion is performed. 4395** 4396** ^The sqlite3_column_type() routine returns the 4397** [SQLITE_INTEGER | datatype code] for the initial data type 4398** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4399** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4400** The return value of sqlite3_column_type() can be used to decide which 4401** of the first six interface should be used to extract the column value. 4402** The value returned by sqlite3_column_type() is only meaningful if no 4403** automatic type conversions have occurred for the value in question. 4404** After a type conversion, the result of calling sqlite3_column_type() 4405** is undefined, though harmless. Future 4406** versions of SQLite may change the behavior of sqlite3_column_type() 4407** following a type conversion. 4408** 4409** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4410** or sqlite3_column_bytes16() interfaces can be used to determine the size 4411** of that BLOB or string. 4412** 4413** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4414** routine returns the number of bytes in that BLOB or string. 4415** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4416** the string to UTF-8 and then returns the number of bytes. 4417** ^If the result is a numeric value then sqlite3_column_bytes() uses 4418** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4419** the number of bytes in that string. 4420** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4421** 4422** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4423** routine returns the number of bytes in that BLOB or string. 4424** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4425** the string to UTF-16 and then returns the number of bytes. 4426** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4427** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4428** the number of bytes in that string. 4429** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4430** 4431** ^The values returned by [sqlite3_column_bytes()] and 4432** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4433** of the string. ^For clarity: the values returned by 4434** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4435** bytes in the string, not the number of characters. 4436** 4437** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4438** even empty strings, are always zero-terminated. ^The return 4439** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4440** 4441** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4442** [unprotected sqlite3_value] object. In a multithreaded environment, 4443** an unprotected sqlite3_value object may only be used safely with 4444** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4445** If the [unprotected sqlite3_value] object returned by 4446** [sqlite3_column_value()] is used in any other way, including calls 4447** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4448** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4449** Hence, the sqlite3_column_value() interface 4450** is normally only useful within the implementation of 4451** [application-defined SQL functions] or [virtual tables], not within 4452** top-level application code. 4453** 4454** The these routines may attempt to convert the datatype of the result. 4455** ^For example, if the internal representation is FLOAT and a text result 4456** is requested, [sqlite3_snprintf()] is used internally to perform the 4457** conversion automatically. ^(The following table details the conversions 4458** that are applied: 4459** 4460** <blockquote> 4461** <table border="1"> 4462** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4463** 4464** <tr><td> NULL <td> INTEGER <td> Result is 0 4465** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4466** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4467** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4468** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4469** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4470** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4471** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4472** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4473** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4474** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4475** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4476** <tr><td> TEXT <td> BLOB <td> No change 4477** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4478** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4479** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4480** </table> 4481** </blockquote>)^ 4482** 4483** Note that when type conversions occur, pointers returned by prior 4484** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4485** sqlite3_column_text16() may be invalidated. 4486** Type conversions and pointer invalidations might occur 4487** in the following cases: 4488** 4489** <ul> 4490** <li> The initial content is a BLOB and sqlite3_column_text() or 4491** sqlite3_column_text16() is called. A zero-terminator might 4492** need to be added to the string.</li> 4493** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4494** sqlite3_column_text16() is called. The content must be converted 4495** to UTF-16.</li> 4496** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4497** sqlite3_column_text() is called. The content must be converted 4498** to UTF-8.</li> 4499** </ul> 4500** 4501** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4502** not invalidate a prior pointer, though of course the content of the buffer 4503** that the prior pointer references will have been modified. Other kinds 4504** of conversion are done in place when it is possible, but sometimes they 4505** are not possible and in those cases prior pointers are invalidated. 4506** 4507** The safest policy is to invoke these routines 4508** in one of the following ways: 4509** 4510** <ul> 4511** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4512** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4513** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4514** </ul> 4515** 4516** In other words, you should call sqlite3_column_text(), 4517** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4518** into the desired format, then invoke sqlite3_column_bytes() or 4519** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4520** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4521** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4522** with calls to sqlite3_column_bytes(). 4523** 4524** ^The pointers returned are valid until a type conversion occurs as 4525** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4526** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4527** and BLOBs is freed automatically. Do not pass the pointers returned 4528** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4529** [sqlite3_free()]. 4530** 4531** ^(If a memory allocation error occurs during the evaluation of any 4532** of these routines, a default value is returned. The default value 4533** is either the integer 0, the floating point number 0.0, or a NULL 4534** pointer. Subsequent calls to [sqlite3_errcode()] will return 4535** [SQLITE_NOMEM].)^ 4536*/ 4537const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4538double sqlite3_column_double(sqlite3_stmt*, int iCol); 4539int sqlite3_column_int(sqlite3_stmt*, int iCol); 4540sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4541const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4542const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4543sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4544int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4545int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4546int sqlite3_column_type(sqlite3_stmt*, int iCol); 4547 4548/* 4549** CAPI3REF: Destroy A Prepared Statement Object 4550** DESTRUCTOR: sqlite3_stmt 4551** 4552** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4553** ^If the most recent evaluation of the statement encountered no errors 4554** or if the statement is never been evaluated, then sqlite3_finalize() returns 4555** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4556** sqlite3_finalize(S) returns the appropriate [error code] or 4557** [extended error code]. 4558** 4559** ^The sqlite3_finalize(S) routine can be called at any point during 4560** the life cycle of [prepared statement] S: 4561** before statement S is ever evaluated, after 4562** one or more calls to [sqlite3_reset()], or after any call 4563** to [sqlite3_step()] regardless of whether or not the statement has 4564** completed execution. 4565** 4566** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4567** 4568** The application must finalize every [prepared statement] in order to avoid 4569** resource leaks. It is a grievous error for the application to try to use 4570** a prepared statement after it has been finalized. Any use of a prepared 4571** statement after it has been finalized can result in undefined and 4572** undesirable behavior such as segfaults and heap corruption. 4573*/ 4574int sqlite3_finalize(sqlite3_stmt *pStmt); 4575 4576/* 4577** CAPI3REF: Reset A Prepared Statement Object 4578** METHOD: sqlite3_stmt 4579** 4580** The sqlite3_reset() function is called to reset a [prepared statement] 4581** object back to its initial state, ready to be re-executed. 4582** ^Any SQL statement variables that had values bound to them using 4583** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4584** Use [sqlite3_clear_bindings()] to reset the bindings. 4585** 4586** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4587** back to the beginning of its program. 4588** 4589** ^If the most recent call to [sqlite3_step(S)] for the 4590** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4591** or if [sqlite3_step(S)] has never before been called on S, 4592** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4593** 4594** ^If the most recent call to [sqlite3_step(S)] for the 4595** [prepared statement] S indicated an error, then 4596** [sqlite3_reset(S)] returns an appropriate [error code]. 4597** 4598** ^The [sqlite3_reset(S)] interface does not change the values 4599** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4600*/ 4601int sqlite3_reset(sqlite3_stmt *pStmt); 4602 4603/* 4604** CAPI3REF: Create Or Redefine SQL Functions 4605** KEYWORDS: {function creation routines} 4606** KEYWORDS: {application-defined SQL function} 4607** KEYWORDS: {application-defined SQL functions} 4608** METHOD: sqlite3 4609** 4610** ^These functions (collectively known as "function creation routines") 4611** are used to add SQL functions or aggregates or to redefine the behavior 4612** of existing SQL functions or aggregates. The only differences between 4613** these routines are the text encoding expected for 4614** the second parameter (the name of the function being created) 4615** and the presence or absence of a destructor callback for 4616** the application data pointer. 4617** 4618** ^The first parameter is the [database connection] to which the SQL 4619** function is to be added. ^If an application uses more than one database 4620** connection then application-defined SQL functions must be added 4621** to each database connection separately. 4622** 4623** ^The second parameter is the name of the SQL function to be created or 4624** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4625** representation, exclusive of the zero-terminator. ^Note that the name 4626** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4627** ^Any attempt to create a function with a longer name 4628** will result in [SQLITE_MISUSE] being returned. 4629** 4630** ^The third parameter (nArg) 4631** is the number of arguments that the SQL function or 4632** aggregate takes. ^If this parameter is -1, then the SQL function or 4633** aggregate may take any number of arguments between 0 and the limit 4634** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4635** parameter is less than -1 or greater than 127 then the behavior is 4636** undefined. 4637** 4638** ^The fourth parameter, eTextRep, specifies what 4639** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4640** its parameters. The application should set this parameter to 4641** [SQLITE_UTF16LE] if the function implementation invokes 4642** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4643** implementation invokes [sqlite3_value_text16be()] on an input, or 4644** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4645** otherwise. ^The same SQL function may be registered multiple times using 4646** different preferred text encodings, with different implementations for 4647** each encoding. 4648** ^When multiple implementations of the same function are available, SQLite 4649** will pick the one that involves the least amount of data conversion. 4650** 4651** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4652** to signal that the function will always return the same result given 4653** the same inputs within a single SQL statement. Most SQL functions are 4654** deterministic. The built-in [random()] SQL function is an example of a 4655** function that is not deterministic. The SQLite query planner is able to 4656** perform additional optimizations on deterministic functions, so use 4657** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4658** 4659** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4660** function can gain access to this pointer using [sqlite3_user_data()].)^ 4661** 4662** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4663** pointers to C-language functions that implement the SQL function or 4664** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4665** callback only; NULL pointers must be passed as the xStep and xFinal 4666** parameters. ^An aggregate SQL function requires an implementation of xStep 4667** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4668** SQL function or aggregate, pass NULL pointers for all three function 4669** callbacks. 4670** 4671** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4672** then it is destructor for the application data pointer. 4673** The destructor is invoked when the function is deleted, either by being 4674** overloaded or when the database connection closes.)^ 4675** ^The destructor is also invoked if the call to 4676** sqlite3_create_function_v2() fails. 4677** ^When the destructor callback of the tenth parameter is invoked, it 4678** is passed a single argument which is a copy of the application data 4679** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4680** 4681** ^It is permitted to register multiple implementations of the same 4682** functions with the same name but with either differing numbers of 4683** arguments or differing preferred text encodings. ^SQLite will use 4684** the implementation that most closely matches the way in which the 4685** SQL function is used. ^A function implementation with a non-negative 4686** nArg parameter is a better match than a function implementation with 4687** a negative nArg. ^A function where the preferred text encoding 4688** matches the database encoding is a better 4689** match than a function where the encoding is different. 4690** ^A function where the encoding difference is between UTF16le and UTF16be 4691** is a closer match than a function where the encoding difference is 4692** between UTF8 and UTF16. 4693** 4694** ^Built-in functions may be overloaded by new application-defined functions. 4695** 4696** ^An application-defined function is permitted to call other 4697** SQLite interfaces. However, such calls must not 4698** close the database connection nor finalize or reset the prepared 4699** statement in which the function is running. 4700*/ 4701int sqlite3_create_function( 4702 sqlite3 *db, 4703 const char *zFunctionName, 4704 int nArg, 4705 int eTextRep, 4706 void *pApp, 4707 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4708 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4709 void (*xFinal)(sqlite3_context*) 4710); 4711int sqlite3_create_function16( 4712 sqlite3 *db, 4713 const void *zFunctionName, 4714 int nArg, 4715 int eTextRep, 4716 void *pApp, 4717 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4718 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4719 void (*xFinal)(sqlite3_context*) 4720); 4721int sqlite3_create_function_v2( 4722 sqlite3 *db, 4723 const char *zFunctionName, 4724 int nArg, 4725 int eTextRep, 4726 void *pApp, 4727 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4728 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4729 void (*xFinal)(sqlite3_context*), 4730 void(*xDestroy)(void*) 4731); 4732 4733/* 4734** CAPI3REF: Text Encodings 4735** 4736** These constant define integer codes that represent the various 4737** text encodings supported by SQLite. 4738*/ 4739#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4740#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4741#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4742#define SQLITE_UTF16 4 /* Use native byte order */ 4743#define SQLITE_ANY 5 /* Deprecated */ 4744#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4745 4746/* 4747** CAPI3REF: Function Flags 4748** 4749** These constants may be ORed together with the 4750** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4751** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4752** [sqlite3_create_function_v2()]. 4753*/ 4754#define SQLITE_DETERMINISTIC 0x800 4755 4756/* 4757** CAPI3REF: Deprecated Functions 4758** DEPRECATED 4759** 4760** These functions are [deprecated]. In order to maintain 4761** backwards compatibility with older code, these functions continue 4762** to be supported. However, new applications should avoid 4763** the use of these functions. To encourage programmers to avoid 4764** these functions, we will not explain what they do. 4765*/ 4766#ifndef SQLITE_OMIT_DEPRECATED 4767SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4768SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4769SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4770SQLITE_DEPRECATED int sqlite3_global_recover(void); 4771SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4772SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4773 void*,sqlite3_int64); 4774#endif 4775 4776/* 4777** CAPI3REF: Obtaining SQL Values 4778** METHOD: sqlite3_value 4779** 4780** <b>Summary:</b> 4781** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4782** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4783** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4784** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4785** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4786** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4787** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4788** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4789** the native byteorder 4790** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4791** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4792** <tr><td> <td> <td> 4793** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4794** or a UTF-8 TEXT in bytes 4795** <tr><td><b>sqlite3_value_bytes16 </b> 4796** <td>→ <td>Size of UTF-16 4797** TEXT in bytes 4798** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4799** datatype of the value 4800** <tr><td><b>sqlite3_value_numeric_type </b> 4801** <td>→ <td>Best numeric datatype of the value 4802** </table></blockquote> 4803** 4804** <b>Details:</b> 4805** 4806** These routines extract type, size, and content information from 4807** [protected sqlite3_value] objects. Protected sqlite3_value objects 4808** are used to pass parameter information into implementation of 4809** [application-defined SQL functions] and [virtual tables]. 4810** 4811** These routines work only with [protected sqlite3_value] objects. 4812** Any attempt to use these routines on an [unprotected sqlite3_value] 4813** is not threadsafe. 4814** 4815** ^These routines work just like the corresponding [column access functions] 4816** except that these routines take a single [protected sqlite3_value] object 4817** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4818** 4819** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4820** in the native byte-order of the host machine. ^The 4821** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4822** extract UTF-16 strings as big-endian and little-endian respectively. 4823** 4824** ^If [sqlite3_value] object V was initialized 4825** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4826** and if X and Y are strings that compare equal according to strcmp(X,Y), 4827** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4828** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4829** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4830** 4831** ^(The sqlite3_value_type(V) interface returns the 4832** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4833** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4834** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4835** Other interfaces might change the datatype for an sqlite3_value object. 4836** For example, if the datatype is initially SQLITE_INTEGER and 4837** sqlite3_value_text(V) is called to extract a text value for that 4838** integer, then subsequent calls to sqlite3_value_type(V) might return 4839** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4840** occurs is undefined and may change from one release of SQLite to the next. 4841** 4842** ^(The sqlite3_value_numeric_type() interface attempts to apply 4843** numeric affinity to the value. This means that an attempt is 4844** made to convert the value to an integer or floating point. If 4845** such a conversion is possible without loss of information (in other 4846** words, if the value is a string that looks like a number) 4847** then the conversion is performed. Otherwise no conversion occurs. 4848** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4849** 4850** Please pay particular attention to the fact that the pointer returned 4851** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4852** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4853** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4854** or [sqlite3_value_text16()]. 4855** 4856** These routines must be called from the same thread as 4857** the SQL function that supplied the [sqlite3_value*] parameters. 4858*/ 4859const void *sqlite3_value_blob(sqlite3_value*); 4860double sqlite3_value_double(sqlite3_value*); 4861int sqlite3_value_int(sqlite3_value*); 4862sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4863void *sqlite3_value_pointer(sqlite3_value*, const char*); 4864const unsigned char *sqlite3_value_text(sqlite3_value*); 4865const void *sqlite3_value_text16(sqlite3_value*); 4866const void *sqlite3_value_text16le(sqlite3_value*); 4867const void *sqlite3_value_text16be(sqlite3_value*); 4868int sqlite3_value_bytes(sqlite3_value*); 4869int sqlite3_value_bytes16(sqlite3_value*); 4870int sqlite3_value_type(sqlite3_value*); 4871int sqlite3_value_numeric_type(sqlite3_value*); 4872 4873/* 4874** CAPI3REF: Finding The Subtype Of SQL Values 4875** METHOD: sqlite3_value 4876** 4877** The sqlite3_value_subtype(V) function returns the subtype for 4878** an [application-defined SQL function] argument V. The subtype 4879** information can be used to pass a limited amount of context from 4880** one SQL function to another. Use the [sqlite3_result_subtype()] 4881** routine to set the subtype for the return value of an SQL function. 4882*/ 4883unsigned int sqlite3_value_subtype(sqlite3_value*); 4884 4885/* 4886** CAPI3REF: Copy And Free SQL Values 4887** METHOD: sqlite3_value 4888** 4889** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4890** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4891** is a [protected sqlite3_value] object even if the input is not. 4892** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4893** memory allocation fails. 4894** 4895** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4896** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4897** then sqlite3_value_free(V) is a harmless no-op. 4898*/ 4899sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4900void sqlite3_value_free(sqlite3_value*); 4901 4902/* 4903** CAPI3REF: Obtain Aggregate Function Context 4904** METHOD: sqlite3_context 4905** 4906** Implementations of aggregate SQL functions use this 4907** routine to allocate memory for storing their state. 4908** 4909** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4910** for a particular aggregate function, SQLite 4911** allocates N of memory, zeroes out that memory, and returns a pointer 4912** to the new memory. ^On second and subsequent calls to 4913** sqlite3_aggregate_context() for the same aggregate function instance, 4914** the same buffer is returned. Sqlite3_aggregate_context() is normally 4915** called once for each invocation of the xStep callback and then one 4916** last time when the xFinal callback is invoked. ^(When no rows match 4917** an aggregate query, the xStep() callback of the aggregate function 4918** implementation is never called and xFinal() is called exactly once. 4919** In those cases, sqlite3_aggregate_context() might be called for the 4920** first time from within xFinal().)^ 4921** 4922** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4923** when first called if N is less than or equal to zero or if a memory 4924** allocate error occurs. 4925** 4926** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4927** determined by the N parameter on first successful call. Changing the 4928** value of N in subsequent call to sqlite3_aggregate_context() within 4929** the same aggregate function instance will not resize the memory 4930** allocation.)^ Within the xFinal callback, it is customary to set 4931** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4932** pointless memory allocations occur. 4933** 4934** ^SQLite automatically frees the memory allocated by 4935** sqlite3_aggregate_context() when the aggregate query concludes. 4936** 4937** The first parameter must be a copy of the 4938** [sqlite3_context | SQL function context] that is the first parameter 4939** to the xStep or xFinal callback routine that implements the aggregate 4940** function. 4941** 4942** This routine must be called from the same thread in which 4943** the aggregate SQL function is running. 4944*/ 4945void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4946 4947/* 4948** CAPI3REF: User Data For Functions 4949** METHOD: sqlite3_context 4950** 4951** ^The sqlite3_user_data() interface returns a copy of 4952** the pointer that was the pUserData parameter (the 5th parameter) 4953** of the [sqlite3_create_function()] 4954** and [sqlite3_create_function16()] routines that originally 4955** registered the application defined function. 4956** 4957** This routine must be called from the same thread in which 4958** the application-defined function is running. 4959*/ 4960void *sqlite3_user_data(sqlite3_context*); 4961 4962/* 4963** CAPI3REF: Database Connection For Functions 4964** METHOD: sqlite3_context 4965** 4966** ^The sqlite3_context_db_handle() interface returns a copy of 4967** the pointer to the [database connection] (the 1st parameter) 4968** of the [sqlite3_create_function()] 4969** and [sqlite3_create_function16()] routines that originally 4970** registered the application defined function. 4971*/ 4972sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4973 4974/* 4975** CAPI3REF: Function Auxiliary Data 4976** METHOD: sqlite3_context 4977** 4978** These functions may be used by (non-aggregate) SQL functions to 4979** associate metadata with argument values. If the same value is passed to 4980** multiple invocations of the same SQL function during query execution, under 4981** some circumstances the associated metadata may be preserved. An example 4982** of where this might be useful is in a regular-expression matching 4983** function. The compiled version of the regular expression can be stored as 4984** metadata associated with the pattern string. 4985** Then as long as the pattern string remains the same, 4986** the compiled regular expression can be reused on multiple 4987** invocations of the same function. 4988** 4989** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4990** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4991** value to the application-defined function. ^N is zero for the left-most 4992** function argument. ^If there is no metadata 4993** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4994** returns a NULL pointer. 4995** 4996** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4997** argument of the application-defined function. ^Subsequent 4998** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4999** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5000** NULL if the metadata has been discarded. 5001** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5002** SQLite will invoke the destructor function X with parameter P exactly 5003** once, when the metadata is discarded. 5004** SQLite is free to discard the metadata at any time, including: <ul> 5005** <li> ^(when the corresponding function parameter changes)^, or 5006** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5007** SQL statement)^, or 5008** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5009** parameter)^, or 5010** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5011** allocation error occurs.)^ </ul> 5012** 5013** Note the last bullet in particular. The destructor X in 5014** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5015** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5016** should be called near the end of the function implementation and the 5017** function implementation should not make any use of P after 5018** sqlite3_set_auxdata() has been called. 5019** 5020** ^(In practice, metadata is preserved between function calls for 5021** function parameters that are compile-time constants, including literal 5022** values and [parameters] and expressions composed from the same.)^ 5023** 5024** The value of the N parameter to these interfaces should be non-negative. 5025** Future enhancements may make use of negative N values to define new 5026** kinds of function caching behavior. 5027** 5028** These routines must be called from the same thread in which 5029** the SQL function is running. 5030*/ 5031void *sqlite3_get_auxdata(sqlite3_context*, int N); 5032void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5033 5034 5035/* 5036** CAPI3REF: Constants Defining Special Destructor Behavior 5037** 5038** These are special values for the destructor that is passed in as the 5039** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5040** argument is SQLITE_STATIC, it means that the content pointer is constant 5041** and will never change. It does not need to be destroyed. ^The 5042** SQLITE_TRANSIENT value means that the content will likely change in 5043** the near future and that SQLite should make its own private copy of 5044** the content before returning. 5045** 5046** The typedef is necessary to work around problems in certain 5047** C++ compilers. 5048*/ 5049typedef void (*sqlite3_destructor_type)(void*); 5050#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5051#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5052 5053/* 5054** CAPI3REF: Setting The Result Of An SQL Function 5055** METHOD: sqlite3_context 5056** 5057** These routines are used by the xFunc or xFinal callbacks that 5058** implement SQL functions and aggregates. See 5059** [sqlite3_create_function()] and [sqlite3_create_function16()] 5060** for additional information. 5061** 5062** These functions work very much like the [parameter binding] family of 5063** functions used to bind values to host parameters in prepared statements. 5064** Refer to the [SQL parameter] documentation for additional information. 5065** 5066** ^The sqlite3_result_blob() interface sets the result from 5067** an application-defined function to be the BLOB whose content is pointed 5068** to by the second parameter and which is N bytes long where N is the 5069** third parameter. 5070** 5071** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5072** interfaces set the result of the application-defined function to be 5073** a BLOB containing all zero bytes and N bytes in size. 5074** 5075** ^The sqlite3_result_double() interface sets the result from 5076** an application-defined function to be a floating point value specified 5077** by its 2nd argument. 5078** 5079** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5080** cause the implemented SQL function to throw an exception. 5081** ^SQLite uses the string pointed to by the 5082** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5083** as the text of an error message. ^SQLite interprets the error 5084** message string from sqlite3_result_error() as UTF-8. ^SQLite 5085** interprets the string from sqlite3_result_error16() as UTF-16 in native 5086** byte order. ^If the third parameter to sqlite3_result_error() 5087** or sqlite3_result_error16() is negative then SQLite takes as the error 5088** message all text up through the first zero character. 5089** ^If the third parameter to sqlite3_result_error() or 5090** sqlite3_result_error16() is non-negative then SQLite takes that many 5091** bytes (not characters) from the 2nd parameter as the error message. 5092** ^The sqlite3_result_error() and sqlite3_result_error16() 5093** routines make a private copy of the error message text before 5094** they return. Hence, the calling function can deallocate or 5095** modify the text after they return without harm. 5096** ^The sqlite3_result_error_code() function changes the error code 5097** returned by SQLite as a result of an error in a function. ^By default, 5098** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5099** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5100** 5101** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5102** error indicating that a string or BLOB is too long to represent. 5103** 5104** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5105** error indicating that a memory allocation failed. 5106** 5107** ^The sqlite3_result_int() interface sets the return value 5108** of the application-defined function to be the 32-bit signed integer 5109** value given in the 2nd argument. 5110** ^The sqlite3_result_int64() interface sets the return value 5111** of the application-defined function to be the 64-bit signed integer 5112** value given in the 2nd argument. 5113** 5114** ^The sqlite3_result_null() interface sets the return value 5115** of the application-defined function to be NULL. 5116** 5117** ^The sqlite3_result_text(), sqlite3_result_text16(), 5118** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5119** set the return value of the application-defined function to be 5120** a text string which is represented as UTF-8, UTF-16 native byte order, 5121** UTF-16 little endian, or UTF-16 big endian, respectively. 5122** ^The sqlite3_result_text64() interface sets the return value of an 5123** application-defined function to be a text string in an encoding 5124** specified by the fifth (and last) parameter, which must be one 5125** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5126** ^SQLite takes the text result from the application from 5127** the 2nd parameter of the sqlite3_result_text* interfaces. 5128** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5129** is negative, then SQLite takes result text from the 2nd parameter 5130** through the first zero character. 5131** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5132** is non-negative, then as many bytes (not characters) of the text 5133** pointed to by the 2nd parameter are taken as the application-defined 5134** function result. If the 3rd parameter is non-negative, then it 5135** must be the byte offset into the string where the NUL terminator would 5136** appear if the string where NUL terminated. If any NUL characters occur 5137** in the string at a byte offset that is less than the value of the 3rd 5138** parameter, then the resulting string will contain embedded NULs and the 5139** result of expressions operating on strings with embedded NULs is undefined. 5140** ^If the 4th parameter to the sqlite3_result_text* interfaces 5141** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5142** function as the destructor on the text or BLOB result when it has 5143** finished using that result. 5144** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5145** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5146** assumes that the text or BLOB result is in constant space and does not 5147** copy the content of the parameter nor call a destructor on the content 5148** when it has finished using that result. 5149** ^If the 4th parameter to the sqlite3_result_text* interfaces 5150** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5151** then SQLite makes a copy of the result into space obtained 5152** from [sqlite3_malloc()] before it returns. 5153** 5154** ^The sqlite3_result_value() interface sets the result of 5155** the application-defined function to be a copy of the 5156** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5157** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5158** so that the [sqlite3_value] specified in the parameter may change or 5159** be deallocated after sqlite3_result_value() returns without harm. 5160** ^A [protected sqlite3_value] object may always be used where an 5161** [unprotected sqlite3_value] object is required, so either 5162** kind of [sqlite3_value] object can be used with this interface. 5163** 5164** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5165** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5166** also associates the host-language pointer P or type T with that 5167** NULL value such that the pointer can be retrieved within an 5168** [application-defined SQL function] using [sqlite3_value_pointer()]. 5169** ^If the D parameter is not NULL, then it is a pointer to a destructor 5170** for the P parameter. ^SQLite invokes D with P as its only argument 5171** when SQLite is finished with P. The T parameter should be a static 5172** string and preferably a string literal. The sqlite3_result_pointer() 5173** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5174** 5175** If these routines are called from within the different thread 5176** than the one containing the application-defined function that received 5177** the [sqlite3_context] pointer, the results are undefined. 5178*/ 5179void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5180void sqlite3_result_blob64(sqlite3_context*,const void*, 5181 sqlite3_uint64,void(*)(void*)); 5182void sqlite3_result_double(sqlite3_context*, double); 5183void sqlite3_result_error(sqlite3_context*, const char*, int); 5184void sqlite3_result_error16(sqlite3_context*, const void*, int); 5185void sqlite3_result_error_toobig(sqlite3_context*); 5186void sqlite3_result_error_nomem(sqlite3_context*); 5187void sqlite3_result_error_code(sqlite3_context*, int); 5188void sqlite3_result_int(sqlite3_context*, int); 5189void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5190void sqlite3_result_null(sqlite3_context*); 5191void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5192void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5193 void(*)(void*), unsigned char encoding); 5194void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5195void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5196void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5197void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5198void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5199void sqlite3_result_zeroblob(sqlite3_context*, int n); 5200int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5201 5202 5203/* 5204** CAPI3REF: Setting The Subtype Of An SQL Function 5205** METHOD: sqlite3_context 5206** 5207** The sqlite3_result_subtype(C,T) function causes the subtype of 5208** the result from the [application-defined SQL function] with 5209** [sqlite3_context] C to be the value T. Only the lower 8 bits 5210** of the subtype T are preserved in current versions of SQLite; 5211** higher order bits are discarded. 5212** The number of subtype bytes preserved by SQLite might increase 5213** in future releases of SQLite. 5214*/ 5215void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5216 5217/* 5218** CAPI3REF: Define New Collating Sequences 5219** METHOD: sqlite3 5220** 5221** ^These functions add, remove, or modify a [collation] associated 5222** with the [database connection] specified as the first argument. 5223** 5224** ^The name of the collation is a UTF-8 string 5225** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5226** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5227** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5228** considered to be the same name. 5229** 5230** ^(The third argument (eTextRep) must be one of the constants: 5231** <ul> 5232** <li> [SQLITE_UTF8], 5233** <li> [SQLITE_UTF16LE], 5234** <li> [SQLITE_UTF16BE], 5235** <li> [SQLITE_UTF16], or 5236** <li> [SQLITE_UTF16_ALIGNED]. 5237** </ul>)^ 5238** ^The eTextRep argument determines the encoding of strings passed 5239** to the collating function callback, xCallback. 5240** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5241** force strings to be UTF16 with native byte order. 5242** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5243** on an even byte address. 5244** 5245** ^The fourth argument, pArg, is an application data pointer that is passed 5246** through as the first argument to the collating function callback. 5247** 5248** ^The fifth argument, xCallback, is a pointer to the collating function. 5249** ^Multiple collating functions can be registered using the same name but 5250** with different eTextRep parameters and SQLite will use whichever 5251** function requires the least amount of data transformation. 5252** ^If the xCallback argument is NULL then the collating function is 5253** deleted. ^When all collating functions having the same name are deleted, 5254** that collation is no longer usable. 5255** 5256** ^The collating function callback is invoked with a copy of the pArg 5257** application data pointer and with two strings in the encoding specified 5258** by the eTextRep argument. The collating function must return an 5259** integer that is negative, zero, or positive 5260** if the first string is less than, equal to, or greater than the second, 5261** respectively. A collating function must always return the same answer 5262** given the same inputs. If two or more collating functions are registered 5263** to the same collation name (using different eTextRep values) then all 5264** must give an equivalent answer when invoked with equivalent strings. 5265** The collating function must obey the following properties for all 5266** strings A, B, and C: 5267** 5268** <ol> 5269** <li> If A==B then B==A. 5270** <li> If A==B and B==C then A==C. 5271** <li> If A<B THEN B>A. 5272** <li> If A<B and B<C then A<C. 5273** </ol> 5274** 5275** If a collating function fails any of the above constraints and that 5276** collating function is registered and used, then the behavior of SQLite 5277** is undefined. 5278** 5279** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5280** with the addition that the xDestroy callback is invoked on pArg when 5281** the collating function is deleted. 5282** ^Collating functions are deleted when they are overridden by later 5283** calls to the collation creation functions or when the 5284** [database connection] is closed using [sqlite3_close()]. 5285** 5286** ^The xDestroy callback is <u>not</u> called if the 5287** sqlite3_create_collation_v2() function fails. Applications that invoke 5288** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5289** check the return code and dispose of the application data pointer 5290** themselves rather than expecting SQLite to deal with it for them. 5291** This is different from every other SQLite interface. The inconsistency 5292** is unfortunate but cannot be changed without breaking backwards 5293** compatibility. 5294** 5295** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5296*/ 5297int sqlite3_create_collation( 5298 sqlite3*, 5299 const char *zName, 5300 int eTextRep, 5301 void *pArg, 5302 int(*xCompare)(void*,int,const void*,int,const void*) 5303); 5304int sqlite3_create_collation_v2( 5305 sqlite3*, 5306 const char *zName, 5307 int eTextRep, 5308 void *pArg, 5309 int(*xCompare)(void*,int,const void*,int,const void*), 5310 void(*xDestroy)(void*) 5311); 5312int sqlite3_create_collation16( 5313 sqlite3*, 5314 const void *zName, 5315 int eTextRep, 5316 void *pArg, 5317 int(*xCompare)(void*,int,const void*,int,const void*) 5318); 5319 5320/* 5321** CAPI3REF: Collation Needed Callbacks 5322** METHOD: sqlite3 5323** 5324** ^To avoid having to register all collation sequences before a database 5325** can be used, a single callback function may be registered with the 5326** [database connection] to be invoked whenever an undefined collation 5327** sequence is required. 5328** 5329** ^If the function is registered using the sqlite3_collation_needed() API, 5330** then it is passed the names of undefined collation sequences as strings 5331** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5332** the names are passed as UTF-16 in machine native byte order. 5333** ^A call to either function replaces the existing collation-needed callback. 5334** 5335** ^(When the callback is invoked, the first argument passed is a copy 5336** of the second argument to sqlite3_collation_needed() or 5337** sqlite3_collation_needed16(). The second argument is the database 5338** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5339** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5340** sequence function required. The fourth parameter is the name of the 5341** required collation sequence.)^ 5342** 5343** The callback function should register the desired collation using 5344** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5345** [sqlite3_create_collation_v2()]. 5346*/ 5347int sqlite3_collation_needed( 5348 sqlite3*, 5349 void*, 5350 void(*)(void*,sqlite3*,int eTextRep,const char*) 5351); 5352int sqlite3_collation_needed16( 5353 sqlite3*, 5354 void*, 5355 void(*)(void*,sqlite3*,int eTextRep,const void*) 5356); 5357 5358#ifdef SQLITE_HAS_CODEC 5359/* 5360** Specify the key for an encrypted database. This routine should be 5361** called right after sqlite3_open(). 5362** 5363** The code to implement this API is not available in the public release 5364** of SQLite. 5365*/ 5366int sqlite3_key( 5367 sqlite3 *db, /* Database to be rekeyed */ 5368 const void *pKey, int nKey /* The key */ 5369); 5370int sqlite3_key_v2( 5371 sqlite3 *db, /* Database to be rekeyed */ 5372 const char *zDbName, /* Name of the database */ 5373 const void *pKey, int nKey /* The key */ 5374); 5375 5376/* 5377** Change the key on an open database. If the current database is not 5378** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5379** database is decrypted. 5380** 5381** The code to implement this API is not available in the public release 5382** of SQLite. 5383*/ 5384int sqlite3_rekey( 5385 sqlite3 *db, /* Database to be rekeyed */ 5386 const void *pKey, int nKey /* The new key */ 5387); 5388int sqlite3_rekey_v2( 5389 sqlite3 *db, /* Database to be rekeyed */ 5390 const char *zDbName, /* Name of the database */ 5391 const void *pKey, int nKey /* The new key */ 5392); 5393 5394/* 5395** Specify the activation key for a SEE database. Unless 5396** activated, none of the SEE routines will work. 5397*/ 5398void sqlite3_activate_see( 5399 const char *zPassPhrase /* Activation phrase */ 5400); 5401#endif 5402 5403#ifdef SQLITE_ENABLE_CEROD 5404/* 5405** Specify the activation key for a CEROD database. Unless 5406** activated, none of the CEROD routines will work. 5407*/ 5408void sqlite3_activate_cerod( 5409 const char *zPassPhrase /* Activation phrase */ 5410); 5411#endif 5412 5413/* 5414** CAPI3REF: Suspend Execution For A Short Time 5415** 5416** The sqlite3_sleep() function causes the current thread to suspend execution 5417** for at least a number of milliseconds specified in its parameter. 5418** 5419** If the operating system does not support sleep requests with 5420** millisecond time resolution, then the time will be rounded up to 5421** the nearest second. The number of milliseconds of sleep actually 5422** requested from the operating system is returned. 5423** 5424** ^SQLite implements this interface by calling the xSleep() 5425** method of the default [sqlite3_vfs] object. If the xSleep() method 5426** of the default VFS is not implemented correctly, or not implemented at 5427** all, then the behavior of sqlite3_sleep() may deviate from the description 5428** in the previous paragraphs. 5429*/ 5430int sqlite3_sleep(int); 5431 5432/* 5433** CAPI3REF: Name Of The Folder Holding Temporary Files 5434** 5435** ^(If this global variable is made to point to a string which is 5436** the name of a folder (a.k.a. directory), then all temporary files 5437** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5438** will be placed in that directory.)^ ^If this variable 5439** is a NULL pointer, then SQLite performs a search for an appropriate 5440** temporary file directory. 5441** 5442** Applications are strongly discouraged from using this global variable. 5443** It is required to set a temporary folder on Windows Runtime (WinRT). 5444** But for all other platforms, it is highly recommended that applications 5445** neither read nor write this variable. This global variable is a relic 5446** that exists for backwards compatibility of legacy applications and should 5447** be avoided in new projects. 5448** 5449** It is not safe to read or modify this variable in more than one 5450** thread at a time. It is not safe to read or modify this variable 5451** if a [database connection] is being used at the same time in a separate 5452** thread. 5453** It is intended that this variable be set once 5454** as part of process initialization and before any SQLite interface 5455** routines have been called and that this variable remain unchanged 5456** thereafter. 5457** 5458** ^The [temp_store_directory pragma] may modify this variable and cause 5459** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5460** the [temp_store_directory pragma] always assumes that any string 5461** that this variable points to is held in memory obtained from 5462** [sqlite3_malloc] and the pragma may attempt to free that memory 5463** using [sqlite3_free]. 5464** Hence, if this variable is modified directly, either it should be 5465** made NULL or made to point to memory obtained from [sqlite3_malloc] 5466** or else the use of the [temp_store_directory pragma] should be avoided. 5467** Except when requested by the [temp_store_directory pragma], SQLite 5468** does not free the memory that sqlite3_temp_directory points to. If 5469** the application wants that memory to be freed, it must do 5470** so itself, taking care to only do so after all [database connection] 5471** objects have been destroyed. 5472** 5473** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5474** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5475** features that require the use of temporary files may fail. Here is an 5476** example of how to do this using C++ with the Windows Runtime: 5477** 5478** <blockquote><pre> 5479** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5480** TemporaryFolder->Path->Data(); 5481** char zPathBuf[MAX_PATH + 1]; 5482** memset(zPathBuf, 0, sizeof(zPathBuf)); 5483** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5484** NULL, NULL); 5485** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5486** </pre></blockquote> 5487*/ 5488SQLITE_EXTERN char *sqlite3_temp_directory; 5489 5490/* 5491** CAPI3REF: Name Of The Folder Holding Database Files 5492** 5493** ^(If this global variable is made to point to a string which is 5494** the name of a folder (a.k.a. directory), then all database files 5495** specified with a relative pathname and created or accessed by 5496** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5497** to be relative to that directory.)^ ^If this variable is a NULL 5498** pointer, then SQLite assumes that all database files specified 5499** with a relative pathname are relative to the current directory 5500** for the process. Only the windows VFS makes use of this global 5501** variable; it is ignored by the unix VFS. 5502** 5503** Changing the value of this variable while a database connection is 5504** open can result in a corrupt database. 5505** 5506** It is not safe to read or modify this variable in more than one 5507** thread at a time. It is not safe to read or modify this variable 5508** if a [database connection] is being used at the same time in a separate 5509** thread. 5510** It is intended that this variable be set once 5511** as part of process initialization and before any SQLite interface 5512** routines have been called and that this variable remain unchanged 5513** thereafter. 5514** 5515** ^The [data_store_directory pragma] may modify this variable and cause 5516** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5517** the [data_store_directory pragma] always assumes that any string 5518** that this variable points to is held in memory obtained from 5519** [sqlite3_malloc] and the pragma may attempt to free that memory 5520** using [sqlite3_free]. 5521** Hence, if this variable is modified directly, either it should be 5522** made NULL or made to point to memory obtained from [sqlite3_malloc] 5523** or else the use of the [data_store_directory pragma] should be avoided. 5524*/ 5525SQLITE_EXTERN char *sqlite3_data_directory; 5526 5527/* 5528** CAPI3REF: Test For Auto-Commit Mode 5529** KEYWORDS: {autocommit mode} 5530** METHOD: sqlite3 5531** 5532** ^The sqlite3_get_autocommit() interface returns non-zero or 5533** zero if the given database connection is or is not in autocommit mode, 5534** respectively. ^Autocommit mode is on by default. 5535** ^Autocommit mode is disabled by a [BEGIN] statement. 5536** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5537** 5538** If certain kinds of errors occur on a statement within a multi-statement 5539** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5540** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5541** transaction might be rolled back automatically. The only way to 5542** find out whether SQLite automatically rolled back the transaction after 5543** an error is to use this function. 5544** 5545** If another thread changes the autocommit status of the database 5546** connection while this routine is running, then the return value 5547** is undefined. 5548*/ 5549int sqlite3_get_autocommit(sqlite3*); 5550 5551/* 5552** CAPI3REF: Find The Database Handle Of A Prepared Statement 5553** METHOD: sqlite3_stmt 5554** 5555** ^The sqlite3_db_handle interface returns the [database connection] handle 5556** to which a [prepared statement] belongs. ^The [database connection] 5557** returned by sqlite3_db_handle is the same [database connection] 5558** that was the first argument 5559** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5560** create the statement in the first place. 5561*/ 5562sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5563 5564/* 5565** CAPI3REF: Return The Filename For A Database Connection 5566** METHOD: sqlite3 5567** 5568** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5569** associated with database N of connection D. ^The main database file 5570** has the name "main". If there is no attached database N on the database 5571** connection D, or if database N is a temporary or in-memory database, then 5572** a NULL pointer is returned. 5573** 5574** ^The filename returned by this function is the output of the 5575** xFullPathname method of the [VFS]. ^In other words, the filename 5576** will be an absolute pathname, even if the filename used 5577** to open the database originally was a URI or relative pathname. 5578*/ 5579const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5580 5581/* 5582** CAPI3REF: Determine if a database is read-only 5583** METHOD: sqlite3 5584** 5585** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5586** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5587** the name of a database on connection D. 5588*/ 5589int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5590 5591/* 5592** CAPI3REF: Find the next prepared statement 5593** METHOD: sqlite3 5594** 5595** ^This interface returns a pointer to the next [prepared statement] after 5596** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5597** then this interface returns a pointer to the first prepared statement 5598** associated with the database connection pDb. ^If no prepared statement 5599** satisfies the conditions of this routine, it returns NULL. 5600** 5601** The [database connection] pointer D in a call to 5602** [sqlite3_next_stmt(D,S)] must refer to an open database 5603** connection and in particular must not be a NULL pointer. 5604*/ 5605sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5606 5607/* 5608** CAPI3REF: Commit And Rollback Notification Callbacks 5609** METHOD: sqlite3 5610** 5611** ^The sqlite3_commit_hook() interface registers a callback 5612** function to be invoked whenever a transaction is [COMMIT | committed]. 5613** ^Any callback set by a previous call to sqlite3_commit_hook() 5614** for the same database connection is overridden. 5615** ^The sqlite3_rollback_hook() interface registers a callback 5616** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5617** ^Any callback set by a previous call to sqlite3_rollback_hook() 5618** for the same database connection is overridden. 5619** ^The pArg argument is passed through to the callback. 5620** ^If the callback on a commit hook function returns non-zero, 5621** then the commit is converted into a rollback. 5622** 5623** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5624** return the P argument from the previous call of the same function 5625** on the same [database connection] D, or NULL for 5626** the first call for each function on D. 5627** 5628** The commit and rollback hook callbacks are not reentrant. 5629** The callback implementation must not do anything that will modify 5630** the database connection that invoked the callback. Any actions 5631** to modify the database connection must be deferred until after the 5632** completion of the [sqlite3_step()] call that triggered the commit 5633** or rollback hook in the first place. 5634** Note that running any other SQL statements, including SELECT statements, 5635** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5636** the database connections for the meaning of "modify" in this paragraph. 5637** 5638** ^Registering a NULL function disables the callback. 5639** 5640** ^When the commit hook callback routine returns zero, the [COMMIT] 5641** operation is allowed to continue normally. ^If the commit hook 5642** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5643** ^The rollback hook is invoked on a rollback that results from a commit 5644** hook returning non-zero, just as it would be with any other rollback. 5645** 5646** ^For the purposes of this API, a transaction is said to have been 5647** rolled back if an explicit "ROLLBACK" statement is executed, or 5648** an error or constraint causes an implicit rollback to occur. 5649** ^The rollback callback is not invoked if a transaction is 5650** automatically rolled back because the database connection is closed. 5651** 5652** See also the [sqlite3_update_hook()] interface. 5653*/ 5654void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5655void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5656 5657/* 5658** CAPI3REF: Data Change Notification Callbacks 5659** METHOD: sqlite3 5660** 5661** ^The sqlite3_update_hook() interface registers a callback function 5662** with the [database connection] identified by the first argument 5663** to be invoked whenever a row is updated, inserted or deleted in 5664** a [rowid table]. 5665** ^Any callback set by a previous call to this function 5666** for the same database connection is overridden. 5667** 5668** ^The second argument is a pointer to the function to invoke when a 5669** row is updated, inserted or deleted in a rowid table. 5670** ^The first argument to the callback is a copy of the third argument 5671** to sqlite3_update_hook(). 5672** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5673** or [SQLITE_UPDATE], depending on the operation that caused the callback 5674** to be invoked. 5675** ^The third and fourth arguments to the callback contain pointers to the 5676** database and table name containing the affected row. 5677** ^The final callback parameter is the [rowid] of the row. 5678** ^In the case of an update, this is the [rowid] after the update takes place. 5679** 5680** ^(The update hook is not invoked when internal system tables are 5681** modified (i.e. sqlite_master and sqlite_sequence).)^ 5682** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5683** 5684** ^In the current implementation, the update hook 5685** is not invoked when conflicting rows are deleted because of an 5686** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5687** invoked when rows are deleted using the [truncate optimization]. 5688** The exceptions defined in this paragraph might change in a future 5689** release of SQLite. 5690** 5691** The update hook implementation must not do anything that will modify 5692** the database connection that invoked the update hook. Any actions 5693** to modify the database connection must be deferred until after the 5694** completion of the [sqlite3_step()] call that triggered the update hook. 5695** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5696** database connections for the meaning of "modify" in this paragraph. 5697** 5698** ^The sqlite3_update_hook(D,C,P) function 5699** returns the P argument from the previous call 5700** on the same [database connection] D, or NULL for 5701** the first call on D. 5702** 5703** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5704** and [sqlite3_preupdate_hook()] interfaces. 5705*/ 5706void *sqlite3_update_hook( 5707 sqlite3*, 5708 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5709 void* 5710); 5711 5712/* 5713** CAPI3REF: Enable Or Disable Shared Pager Cache 5714** 5715** ^(This routine enables or disables the sharing of the database cache 5716** and schema data structures between [database connection | connections] 5717** to the same database. Sharing is enabled if the argument is true 5718** and disabled if the argument is false.)^ 5719** 5720** ^Cache sharing is enabled and disabled for an entire process. 5721** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5722** In prior versions of SQLite, 5723** sharing was enabled or disabled for each thread separately. 5724** 5725** ^(The cache sharing mode set by this interface effects all subsequent 5726** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5727** Existing database connections continue use the sharing mode 5728** that was in effect at the time they were opened.)^ 5729** 5730** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5731** successfully. An [error code] is returned otherwise.)^ 5732** 5733** ^Shared cache is disabled by default. But this might change in 5734** future releases of SQLite. Applications that care about shared 5735** cache setting should set it explicitly. 5736** 5737** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5738** and will always return SQLITE_MISUSE. On those systems, 5739** shared cache mode should be enabled per-database connection via 5740** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5741** 5742** This interface is threadsafe on processors where writing a 5743** 32-bit integer is atomic. 5744** 5745** See Also: [SQLite Shared-Cache Mode] 5746*/ 5747int sqlite3_enable_shared_cache(int); 5748 5749/* 5750** CAPI3REF: Attempt To Free Heap Memory 5751** 5752** ^The sqlite3_release_memory() interface attempts to free N bytes 5753** of heap memory by deallocating non-essential memory allocations 5754** held by the database library. Memory used to cache database 5755** pages to improve performance is an example of non-essential memory. 5756** ^sqlite3_release_memory() returns the number of bytes actually freed, 5757** which might be more or less than the amount requested. 5758** ^The sqlite3_release_memory() routine is a no-op returning zero 5759** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5760** 5761** See also: [sqlite3_db_release_memory()] 5762*/ 5763int sqlite3_release_memory(int); 5764 5765/* 5766** CAPI3REF: Free Memory Used By A Database Connection 5767** METHOD: sqlite3 5768** 5769** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5770** memory as possible from database connection D. Unlike the 5771** [sqlite3_release_memory()] interface, this interface is in effect even 5772** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5773** omitted. 5774** 5775** See also: [sqlite3_release_memory()] 5776*/ 5777int sqlite3_db_release_memory(sqlite3*); 5778 5779/* 5780** CAPI3REF: Impose A Limit On Heap Size 5781** 5782** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5783** soft limit on the amount of heap memory that may be allocated by SQLite. 5784** ^SQLite strives to keep heap memory utilization below the soft heap 5785** limit by reducing the number of pages held in the page cache 5786** as heap memory usages approaches the limit. 5787** ^The soft heap limit is "soft" because even though SQLite strives to stay 5788** below the limit, it will exceed the limit rather than generate 5789** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5790** is advisory only. 5791** 5792** ^The return value from sqlite3_soft_heap_limit64() is the size of 5793** the soft heap limit prior to the call, or negative in the case of an 5794** error. ^If the argument N is negative 5795** then no change is made to the soft heap limit. Hence, the current 5796** size of the soft heap limit can be determined by invoking 5797** sqlite3_soft_heap_limit64() with a negative argument. 5798** 5799** ^If the argument N is zero then the soft heap limit is disabled. 5800** 5801** ^(The soft heap limit is not enforced in the current implementation 5802** if one or more of following conditions are true: 5803** 5804** <ul> 5805** <li> The soft heap limit is set to zero. 5806** <li> Memory accounting is disabled using a combination of the 5807** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5808** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5809** <li> An alternative page cache implementation is specified using 5810** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5811** <li> The page cache allocates from its own memory pool supplied 5812** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5813** from the heap. 5814** </ul>)^ 5815** 5816** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5817** the soft heap limit is enforced 5818** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5819** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5820** the soft heap limit is enforced on every memory allocation. Without 5821** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5822** when memory is allocated by the page cache. Testing suggests that because 5823** the page cache is the predominate memory user in SQLite, most 5824** applications will achieve adequate soft heap limit enforcement without 5825** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5826** 5827** The circumstances under which SQLite will enforce the soft heap limit may 5828** changes in future releases of SQLite. 5829*/ 5830sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5831 5832/* 5833** CAPI3REF: Deprecated Soft Heap Limit Interface 5834** DEPRECATED 5835** 5836** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5837** interface. This routine is provided for historical compatibility 5838** only. All new applications should use the 5839** [sqlite3_soft_heap_limit64()] interface rather than this one. 5840*/ 5841SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5842 5843 5844/* 5845** CAPI3REF: Extract Metadata About A Column Of A Table 5846** METHOD: sqlite3 5847** 5848** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5849** information about column C of table T in database D 5850** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5851** interface returns SQLITE_OK and fills in the non-NULL pointers in 5852** the final five arguments with appropriate values if the specified 5853** column exists. ^The sqlite3_table_column_metadata() interface returns 5854** SQLITE_ERROR and if the specified column does not exist. 5855** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5856** NULL pointer, then this routine simply checks for the existence of the 5857** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5858** does not. If the table name parameter T in a call to 5859** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5860** undefined behavior. 5861** 5862** ^The column is identified by the second, third and fourth parameters to 5863** this function. ^(The second parameter is either the name of the database 5864** (i.e. "main", "temp", or an attached database) containing the specified 5865** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5866** for the table using the same algorithm used by the database engine to 5867** resolve unqualified table references. 5868** 5869** ^The third and fourth parameters to this function are the table and column 5870** name of the desired column, respectively. 5871** 5872** ^Metadata is returned by writing to the memory locations passed as the 5th 5873** and subsequent parameters to this function. ^Any of these arguments may be 5874** NULL, in which case the corresponding element of metadata is omitted. 5875** 5876** ^(<blockquote> 5877** <table border="1"> 5878** <tr><th> Parameter <th> Output<br>Type <th> Description 5879** 5880** <tr><td> 5th <td> const char* <td> Data type 5881** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5882** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5883** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5884** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5885** </table> 5886** </blockquote>)^ 5887** 5888** ^The memory pointed to by the character pointers returned for the 5889** declaration type and collation sequence is valid until the next 5890** call to any SQLite API function. 5891** 5892** ^If the specified table is actually a view, an [error code] is returned. 5893** 5894** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5895** is not a [WITHOUT ROWID] table and an 5896** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5897** parameters are set for the explicitly declared column. ^(If there is no 5898** [INTEGER PRIMARY KEY] column, then the outputs 5899** for the [rowid] are set as follows: 5900** 5901** <pre> 5902** data type: "INTEGER" 5903** collation sequence: "BINARY" 5904** not null: 0 5905** primary key: 1 5906** auto increment: 0 5907** </pre>)^ 5908** 5909** ^This function causes all database schemas to be read from disk and 5910** parsed, if that has not already been done, and returns an error if 5911** any errors are encountered while loading the schema. 5912*/ 5913int sqlite3_table_column_metadata( 5914 sqlite3 *db, /* Connection handle */ 5915 const char *zDbName, /* Database name or NULL */ 5916 const char *zTableName, /* Table name */ 5917 const char *zColumnName, /* Column name */ 5918 char const **pzDataType, /* OUTPUT: Declared data type */ 5919 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5920 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5921 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5922 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5923); 5924 5925/* 5926** CAPI3REF: Load An Extension 5927** METHOD: sqlite3 5928** 5929** ^This interface loads an SQLite extension library from the named file. 5930** 5931** ^The sqlite3_load_extension() interface attempts to load an 5932** [SQLite extension] library contained in the file zFile. If 5933** the file cannot be loaded directly, attempts are made to load 5934** with various operating-system specific extensions added. 5935** So for example, if "samplelib" cannot be loaded, then names like 5936** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5937** be tried also. 5938** 5939** ^The entry point is zProc. 5940** ^(zProc may be 0, in which case SQLite will try to come up with an 5941** entry point name on its own. It first tries "sqlite3_extension_init". 5942** If that does not work, it constructs a name "sqlite3_X_init" where the 5943** X is consists of the lower-case equivalent of all ASCII alphabetic 5944** characters in the filename from the last "/" to the first following 5945** "." and omitting any initial "lib".)^ 5946** ^The sqlite3_load_extension() interface returns 5947** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5948** ^If an error occurs and pzErrMsg is not 0, then the 5949** [sqlite3_load_extension()] interface shall attempt to 5950** fill *pzErrMsg with error message text stored in memory 5951** obtained from [sqlite3_malloc()]. The calling function 5952** should free this memory by calling [sqlite3_free()]. 5953** 5954** ^Extension loading must be enabled using 5955** [sqlite3_enable_load_extension()] or 5956** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5957** prior to calling this API, 5958** otherwise an error will be returned. 5959** 5960** <b>Security warning:</b> It is recommended that the 5961** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5962** interface. The use of the [sqlite3_enable_load_extension()] interface 5963** should be avoided. This will keep the SQL function [load_extension()] 5964** disabled and prevent SQL injections from giving attackers 5965** access to extension loading capabilities. 5966** 5967** See also the [load_extension() SQL function]. 5968*/ 5969int sqlite3_load_extension( 5970 sqlite3 *db, /* Load the extension into this database connection */ 5971 const char *zFile, /* Name of the shared library containing extension */ 5972 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5973 char **pzErrMsg /* Put error message here if not 0 */ 5974); 5975 5976/* 5977** CAPI3REF: Enable Or Disable Extension Loading 5978** METHOD: sqlite3 5979** 5980** ^So as not to open security holes in older applications that are 5981** unprepared to deal with [extension loading], and as a means of disabling 5982** [extension loading] while evaluating user-entered SQL, the following API 5983** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5984** 5985** ^Extension loading is off by default. 5986** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5987** to turn extension loading on and call it with onoff==0 to turn 5988** it back off again. 5989** 5990** ^This interface enables or disables both the C-API 5991** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5992** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5993** to enable or disable only the C-API.)^ 5994** 5995** <b>Security warning:</b> It is recommended that extension loading 5996** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5997** rather than this interface, so the [load_extension()] SQL function 5998** remains disabled. This will prevent SQL injections from giving attackers 5999** access to extension loading capabilities. 6000*/ 6001int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6002 6003/* 6004** CAPI3REF: Automatically Load Statically Linked Extensions 6005** 6006** ^This interface causes the xEntryPoint() function to be invoked for 6007** each new [database connection] that is created. The idea here is that 6008** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6009** that is to be automatically loaded into all new database connections. 6010** 6011** ^(Even though the function prototype shows that xEntryPoint() takes 6012** no arguments and returns void, SQLite invokes xEntryPoint() with three 6013** arguments and expects an integer result as if the signature of the 6014** entry point where as follows: 6015** 6016** <blockquote><pre> 6017** int xEntryPoint( 6018** sqlite3 *db, 6019** const char **pzErrMsg, 6020** const struct sqlite3_api_routines *pThunk 6021** ); 6022** </pre></blockquote>)^ 6023** 6024** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6025** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6026** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6027** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6028** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6029** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6030** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6031** 6032** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6033** on the list of automatic extensions is a harmless no-op. ^No entry point 6034** will be called more than once for each database connection that is opened. 6035** 6036** See also: [sqlite3_reset_auto_extension()] 6037** and [sqlite3_cancel_auto_extension()] 6038*/ 6039int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6040 6041/* 6042** CAPI3REF: Cancel Automatic Extension Loading 6043** 6044** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6045** initialization routine X that was registered using a prior call to 6046** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6047** routine returns 1 if initialization routine X was successfully 6048** unregistered and it returns 0 if X was not on the list of initialization 6049** routines. 6050*/ 6051int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6052 6053/* 6054** CAPI3REF: Reset Automatic Extension Loading 6055** 6056** ^This interface disables all automatic extensions previously 6057** registered using [sqlite3_auto_extension()]. 6058*/ 6059void sqlite3_reset_auto_extension(void); 6060 6061/* 6062** The interface to the virtual-table mechanism is currently considered 6063** to be experimental. The interface might change in incompatible ways. 6064** If this is a problem for you, do not use the interface at this time. 6065** 6066** When the virtual-table mechanism stabilizes, we will declare the 6067** interface fixed, support it indefinitely, and remove this comment. 6068*/ 6069 6070/* 6071** Structures used by the virtual table interface 6072*/ 6073typedef struct sqlite3_vtab sqlite3_vtab; 6074typedef struct sqlite3_index_info sqlite3_index_info; 6075typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6076typedef struct sqlite3_module sqlite3_module; 6077 6078/* 6079** CAPI3REF: Virtual Table Object 6080** KEYWORDS: sqlite3_module {virtual table module} 6081** 6082** This structure, sometimes called a "virtual table module", 6083** defines the implementation of a [virtual tables]. 6084** This structure consists mostly of methods for the module. 6085** 6086** ^A virtual table module is created by filling in a persistent 6087** instance of this structure and passing a pointer to that instance 6088** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6089** ^The registration remains valid until it is replaced by a different 6090** module or until the [database connection] closes. The content 6091** of this structure must not change while it is registered with 6092** any database connection. 6093*/ 6094struct sqlite3_module { 6095 int iVersion; 6096 int (*xCreate)(sqlite3*, void *pAux, 6097 int argc, const char *const*argv, 6098 sqlite3_vtab **ppVTab, char**); 6099 int (*xConnect)(sqlite3*, void *pAux, 6100 int argc, const char *const*argv, 6101 sqlite3_vtab **ppVTab, char**); 6102 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6103 int (*xDisconnect)(sqlite3_vtab *pVTab); 6104 int (*xDestroy)(sqlite3_vtab *pVTab); 6105 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6106 int (*xClose)(sqlite3_vtab_cursor*); 6107 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6108 int argc, sqlite3_value **argv); 6109 int (*xNext)(sqlite3_vtab_cursor*); 6110 int (*xEof)(sqlite3_vtab_cursor*); 6111 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6112 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6113 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6114 int (*xBegin)(sqlite3_vtab *pVTab); 6115 int (*xSync)(sqlite3_vtab *pVTab); 6116 int (*xCommit)(sqlite3_vtab *pVTab); 6117 int (*xRollback)(sqlite3_vtab *pVTab); 6118 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6119 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6120 void **ppArg); 6121 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6122 /* The methods above are in version 1 of the sqlite_module object. Those 6123 ** below are for version 2 and greater. */ 6124 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6125 int (*xRelease)(sqlite3_vtab *pVTab, int); 6126 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6127}; 6128 6129/* 6130** CAPI3REF: Virtual Table Indexing Information 6131** KEYWORDS: sqlite3_index_info 6132** 6133** The sqlite3_index_info structure and its substructures is used as part 6134** of the [virtual table] interface to 6135** pass information into and receive the reply from the [xBestIndex] 6136** method of a [virtual table module]. The fields under **Inputs** are the 6137** inputs to xBestIndex and are read-only. xBestIndex inserts its 6138** results into the **Outputs** fields. 6139** 6140** ^(The aConstraint[] array records WHERE clause constraints of the form: 6141** 6142** <blockquote>column OP expr</blockquote> 6143** 6144** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6145** stored in aConstraint[].op using one of the 6146** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6147** ^(The index of the column is stored in 6148** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6149** expr on the right-hand side can be evaluated (and thus the constraint 6150** is usable) and false if it cannot.)^ 6151** 6152** ^The optimizer automatically inverts terms of the form "expr OP column" 6153** and makes other simplifications to the WHERE clause in an attempt to 6154** get as many WHERE clause terms into the form shown above as possible. 6155** ^The aConstraint[] array only reports WHERE clause terms that are 6156** relevant to the particular virtual table being queried. 6157** 6158** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6159** ^Each term of aOrderBy records a column of the ORDER BY clause. 6160** 6161** The colUsed field indicates which columns of the virtual table may be 6162** required by the current scan. Virtual table columns are numbered from 6163** zero in the order in which they appear within the CREATE TABLE statement 6164** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6165** the corresponding bit is set within the colUsed mask if the column may be 6166** required by SQLite. If the table has at least 64 columns and any column 6167** to the right of the first 63 is required, then bit 63 of colUsed is also 6168** set. In other words, column iCol may be required if the expression 6169** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6170** non-zero. 6171** 6172** The [xBestIndex] method must fill aConstraintUsage[] with information 6173** about what parameters to pass to xFilter. ^If argvIndex>0 then 6174** the right-hand side of the corresponding aConstraint[] is evaluated 6175** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6176** is true, then the constraint is assumed to be fully handled by the 6177** virtual table and is not checked again by SQLite.)^ 6178** 6179** ^The idxNum and idxPtr values are recorded and passed into the 6180** [xFilter] method. 6181** ^[sqlite3_free()] is used to free idxPtr if and only if 6182** needToFreeIdxPtr is true. 6183** 6184** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6185** the correct order to satisfy the ORDER BY clause so that no separate 6186** sorting step is required. 6187** 6188** ^The estimatedCost value is an estimate of the cost of a particular 6189** strategy. A cost of N indicates that the cost of the strategy is similar 6190** to a linear scan of an SQLite table with N rows. A cost of log(N) 6191** indicates that the expense of the operation is similar to that of a 6192** binary search on a unique indexed field of an SQLite table with N rows. 6193** 6194** ^The estimatedRows value is an estimate of the number of rows that 6195** will be returned by the strategy. 6196** 6197** The xBestIndex method may optionally populate the idxFlags field with a 6198** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6199** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6200** assumes that the strategy may visit at most one row. 6201** 6202** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6203** SQLite also assumes that if a call to the xUpdate() method is made as 6204** part of the same statement to delete or update a virtual table row and the 6205** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6206** any database changes. In other words, if the xUpdate() returns 6207** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6208** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6209** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6210** the xUpdate method are automatically rolled back by SQLite. 6211** 6212** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6213** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6214** If a virtual table extension is 6215** used with an SQLite version earlier than 3.8.2, the results of attempting 6216** to read or write the estimatedRows field are undefined (but are likely 6217** to included crashing the application). The estimatedRows field should 6218** therefore only be used if [sqlite3_libversion_number()] returns a 6219** value greater than or equal to 3008002. Similarly, the idxFlags field 6220** was added for [version 3.9.0] ([dateof:3.9.0]). 6221** It may therefore only be used if 6222** sqlite3_libversion_number() returns a value greater than or equal to 6223** 3009000. 6224*/ 6225struct sqlite3_index_info { 6226 /* Inputs */ 6227 int nConstraint; /* Number of entries in aConstraint */ 6228 struct sqlite3_index_constraint { 6229 int iColumn; /* Column constrained. -1 for ROWID */ 6230 unsigned char op; /* Constraint operator */ 6231 unsigned char usable; /* True if this constraint is usable */ 6232 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6233 } *aConstraint; /* Table of WHERE clause constraints */ 6234 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6235 struct sqlite3_index_orderby { 6236 int iColumn; /* Column number */ 6237 unsigned char desc; /* True for DESC. False for ASC. */ 6238 } *aOrderBy; /* The ORDER BY clause */ 6239 /* Outputs */ 6240 struct sqlite3_index_constraint_usage { 6241 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6242 unsigned char omit; /* Do not code a test for this constraint */ 6243 } *aConstraintUsage; 6244 int idxNum; /* Number used to identify the index */ 6245 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6246 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6247 int orderByConsumed; /* True if output is already ordered */ 6248 double estimatedCost; /* Estimated cost of using this index */ 6249 /* Fields below are only available in SQLite 3.8.2 and later */ 6250 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6251 /* Fields below are only available in SQLite 3.9.0 and later */ 6252 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6253 /* Fields below are only available in SQLite 3.10.0 and later */ 6254 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6255}; 6256 6257/* 6258** CAPI3REF: Virtual Table Scan Flags 6259*/ 6260#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6261 6262/* 6263** CAPI3REF: Virtual Table Constraint Operator Codes 6264** 6265** These macros defined the allowed values for the 6266** [sqlite3_index_info].aConstraint[].op field. Each value represents 6267** an operator that is part of a constraint term in the wHERE clause of 6268** a query that uses a [virtual table]. 6269*/ 6270#define SQLITE_INDEX_CONSTRAINT_EQ 2 6271#define SQLITE_INDEX_CONSTRAINT_GT 4 6272#define SQLITE_INDEX_CONSTRAINT_LE 8 6273#define SQLITE_INDEX_CONSTRAINT_LT 16 6274#define SQLITE_INDEX_CONSTRAINT_GE 32 6275#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6276#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6277#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6278#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6279#define SQLITE_INDEX_CONSTRAINT_NE 68 6280#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6281#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6282#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6283#define SQLITE_INDEX_CONSTRAINT_IS 72 6284 6285/* 6286** CAPI3REF: Register A Virtual Table Implementation 6287** METHOD: sqlite3 6288** 6289** ^These routines are used to register a new [virtual table module] name. 6290** ^Module names must be registered before 6291** creating a new [virtual table] using the module and before using a 6292** preexisting [virtual table] for the module. 6293** 6294** ^The module name is registered on the [database connection] specified 6295** by the first parameter. ^The name of the module is given by the 6296** second parameter. ^The third parameter is a pointer to 6297** the implementation of the [virtual table module]. ^The fourth 6298** parameter is an arbitrary client data pointer that is passed through 6299** into the [xCreate] and [xConnect] methods of the virtual table module 6300** when a new virtual table is be being created or reinitialized. 6301** 6302** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6303** is a pointer to a destructor for the pClientData. ^SQLite will 6304** invoke the destructor function (if it is not NULL) when SQLite 6305** no longer needs the pClientData pointer. ^The destructor will also 6306** be invoked if the call to sqlite3_create_module_v2() fails. 6307** ^The sqlite3_create_module() 6308** interface is equivalent to sqlite3_create_module_v2() with a NULL 6309** destructor. 6310*/ 6311int sqlite3_create_module( 6312 sqlite3 *db, /* SQLite connection to register module with */ 6313 const char *zName, /* Name of the module */ 6314 const sqlite3_module *p, /* Methods for the module */ 6315 void *pClientData /* Client data for xCreate/xConnect */ 6316); 6317int sqlite3_create_module_v2( 6318 sqlite3 *db, /* SQLite connection to register module with */ 6319 const char *zName, /* Name of the module */ 6320 const sqlite3_module *p, /* Methods for the module */ 6321 void *pClientData, /* Client data for xCreate/xConnect */ 6322 void(*xDestroy)(void*) /* Module destructor function */ 6323); 6324 6325/* 6326** CAPI3REF: Virtual Table Instance Object 6327** KEYWORDS: sqlite3_vtab 6328** 6329** Every [virtual table module] implementation uses a subclass 6330** of this object to describe a particular instance 6331** of the [virtual table]. Each subclass will 6332** be tailored to the specific needs of the module implementation. 6333** The purpose of this superclass is to define certain fields that are 6334** common to all module implementations. 6335** 6336** ^Virtual tables methods can set an error message by assigning a 6337** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6338** take care that any prior string is freed by a call to [sqlite3_free()] 6339** prior to assigning a new string to zErrMsg. ^After the error message 6340** is delivered up to the client application, the string will be automatically 6341** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6342*/ 6343struct sqlite3_vtab { 6344 const sqlite3_module *pModule; /* The module for this virtual table */ 6345 int nRef; /* Number of open cursors */ 6346 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6347 /* Virtual table implementations will typically add additional fields */ 6348}; 6349 6350/* 6351** CAPI3REF: Virtual Table Cursor Object 6352** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6353** 6354** Every [virtual table module] implementation uses a subclass of the 6355** following structure to describe cursors that point into the 6356** [virtual table] and are used 6357** to loop through the virtual table. Cursors are created using the 6358** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6359** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6360** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6361** of the module. Each module implementation will define 6362** the content of a cursor structure to suit its own needs. 6363** 6364** This superclass exists in order to define fields of the cursor that 6365** are common to all implementations. 6366*/ 6367struct sqlite3_vtab_cursor { 6368 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6369 /* Virtual table implementations will typically add additional fields */ 6370}; 6371 6372/* 6373** CAPI3REF: Declare The Schema Of A Virtual Table 6374** 6375** ^The [xCreate] and [xConnect] methods of a 6376** [virtual table module] call this interface 6377** to declare the format (the names and datatypes of the columns) of 6378** the virtual tables they implement. 6379*/ 6380int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6381 6382/* 6383** CAPI3REF: Overload A Function For A Virtual Table 6384** METHOD: sqlite3 6385** 6386** ^(Virtual tables can provide alternative implementations of functions 6387** using the [xFindFunction] method of the [virtual table module]. 6388** But global versions of those functions 6389** must exist in order to be overloaded.)^ 6390** 6391** ^(This API makes sure a global version of a function with a particular 6392** name and number of parameters exists. If no such function exists 6393** before this API is called, a new function is created.)^ ^The implementation 6394** of the new function always causes an exception to be thrown. So 6395** the new function is not good for anything by itself. Its only 6396** purpose is to be a placeholder function that can be overloaded 6397** by a [virtual table]. 6398*/ 6399int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6400 6401/* 6402** The interface to the virtual-table mechanism defined above (back up 6403** to a comment remarkably similar to this one) is currently considered 6404** to be experimental. The interface might change in incompatible ways. 6405** If this is a problem for you, do not use the interface at this time. 6406** 6407** When the virtual-table mechanism stabilizes, we will declare the 6408** interface fixed, support it indefinitely, and remove this comment. 6409*/ 6410 6411/* 6412** CAPI3REF: A Handle To An Open BLOB 6413** KEYWORDS: {BLOB handle} {BLOB handles} 6414** 6415** An instance of this object represents an open BLOB on which 6416** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6417** ^Objects of this type are created by [sqlite3_blob_open()] 6418** and destroyed by [sqlite3_blob_close()]. 6419** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6420** can be used to read or write small subsections of the BLOB. 6421** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6422*/ 6423typedef struct sqlite3_blob sqlite3_blob; 6424 6425/* 6426** CAPI3REF: Open A BLOB For Incremental I/O 6427** METHOD: sqlite3 6428** CONSTRUCTOR: sqlite3_blob 6429** 6430** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6431** in row iRow, column zColumn, table zTable in database zDb; 6432** in other words, the same BLOB that would be selected by: 6433** 6434** <pre> 6435** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6436** </pre>)^ 6437** 6438** ^(Parameter zDb is not the filename that contains the database, but 6439** rather the symbolic name of the database. For attached databases, this is 6440** the name that appears after the AS keyword in the [ATTACH] statement. 6441** For the main database file, the database name is "main". For TEMP 6442** tables, the database name is "temp".)^ 6443** 6444** ^If the flags parameter is non-zero, then the BLOB is opened for read 6445** and write access. ^If the flags parameter is zero, the BLOB is opened for 6446** read-only access. 6447** 6448** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6449** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6450** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6451** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6452** on *ppBlob after this function it returns. 6453** 6454** This function fails with SQLITE_ERROR if any of the following are true: 6455** <ul> 6456** <li> ^(Database zDb does not exist)^, 6457** <li> ^(Table zTable does not exist within database zDb)^, 6458** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6459** <li> ^(Column zColumn does not exist)^, 6460** <li> ^(Row iRow is not present in the table)^, 6461** <li> ^(The specified column of row iRow contains a value that is not 6462** a TEXT or BLOB value)^, 6463** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6464** constraint and the blob is being opened for read/write access)^, 6465** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6466** column zColumn is part of a [child key] definition and the blob is 6467** being opened for read/write access)^. 6468** </ul> 6469** 6470** ^Unless it returns SQLITE_MISUSE, this function sets the 6471** [database connection] error code and message accessible via 6472** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6473** 6474** A BLOB referenced by sqlite3_blob_open() may be read using the 6475** [sqlite3_blob_read()] interface and modified by using 6476** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6477** different row of the same table using the [sqlite3_blob_reopen()] 6478** interface. However, the column, table, or database of a [BLOB handle] 6479** cannot be changed after the [BLOB handle] is opened. 6480** 6481** ^(If the row that a BLOB handle points to is modified by an 6482** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6483** then the BLOB handle is marked as "expired". 6484** This is true if any column of the row is changed, even a column 6485** other than the one the BLOB handle is open on.)^ 6486** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6487** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6488** ^(Changes written into a BLOB prior to the BLOB expiring are not 6489** rolled back by the expiration of the BLOB. Such changes will eventually 6490** commit if the transaction continues to completion.)^ 6491** 6492** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6493** the opened blob. ^The size of a blob may not be changed by this 6494** interface. Use the [UPDATE] SQL command to change the size of a 6495** blob. 6496** 6497** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6498** and the built-in [zeroblob] SQL function may be used to create a 6499** zero-filled blob to read or write using the incremental-blob interface. 6500** 6501** To avoid a resource leak, every open [BLOB handle] should eventually 6502** be released by a call to [sqlite3_blob_close()]. 6503** 6504** See also: [sqlite3_blob_close()], 6505** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6506** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6507*/ 6508int sqlite3_blob_open( 6509 sqlite3*, 6510 const char *zDb, 6511 const char *zTable, 6512 const char *zColumn, 6513 sqlite3_int64 iRow, 6514 int flags, 6515 sqlite3_blob **ppBlob 6516); 6517 6518/* 6519** CAPI3REF: Move a BLOB Handle to a New Row 6520** METHOD: sqlite3_blob 6521** 6522** ^This function is used to move an existing [BLOB handle] so that it points 6523** to a different row of the same database table. ^The new row is identified 6524** by the rowid value passed as the second argument. Only the row can be 6525** changed. ^The database, table and column on which the blob handle is open 6526** remain the same. Moving an existing [BLOB handle] to a new row is 6527** faster than closing the existing handle and opening a new one. 6528** 6529** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6530** it must exist and there must be either a blob or text value stored in 6531** the nominated column.)^ ^If the new row is not present in the table, or if 6532** it does not contain a blob or text value, or if another error occurs, an 6533** SQLite error code is returned and the blob handle is considered aborted. 6534** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6535** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6536** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6537** always returns zero. 6538** 6539** ^This function sets the database handle error code and message. 6540*/ 6541int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6542 6543/* 6544** CAPI3REF: Close A BLOB Handle 6545** DESTRUCTOR: sqlite3_blob 6546** 6547** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6548** unconditionally. Even if this routine returns an error code, the 6549** handle is still closed.)^ 6550** 6551** ^If the blob handle being closed was opened for read-write access, and if 6552** the database is in auto-commit mode and there are no other open read-write 6553** blob handles or active write statements, the current transaction is 6554** committed. ^If an error occurs while committing the transaction, an error 6555** code is returned and the transaction rolled back. 6556** 6557** Calling this function with an argument that is not a NULL pointer or an 6558** open blob handle results in undefined behaviour. ^Calling this routine 6559** with a null pointer (such as would be returned by a failed call to 6560** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6561** is passed a valid open blob handle, the values returned by the 6562** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6563*/ 6564int sqlite3_blob_close(sqlite3_blob *); 6565 6566/* 6567** CAPI3REF: Return The Size Of An Open BLOB 6568** METHOD: sqlite3_blob 6569** 6570** ^Returns the size in bytes of the BLOB accessible via the 6571** successfully opened [BLOB handle] in its only argument. ^The 6572** incremental blob I/O routines can only read or overwriting existing 6573** blob content; they cannot change the size of a blob. 6574** 6575** This routine only works on a [BLOB handle] which has been created 6576** by a prior successful call to [sqlite3_blob_open()] and which has not 6577** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6578** to this routine results in undefined and probably undesirable behavior. 6579*/ 6580int sqlite3_blob_bytes(sqlite3_blob *); 6581 6582/* 6583** CAPI3REF: Read Data From A BLOB Incrementally 6584** METHOD: sqlite3_blob 6585** 6586** ^(This function is used to read data from an open [BLOB handle] into a 6587** caller-supplied buffer. N bytes of data are copied into buffer Z 6588** from the open BLOB, starting at offset iOffset.)^ 6589** 6590** ^If offset iOffset is less than N bytes from the end of the BLOB, 6591** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6592** less than zero, [SQLITE_ERROR] is returned and no data is read. 6593** ^The size of the blob (and hence the maximum value of N+iOffset) 6594** can be determined using the [sqlite3_blob_bytes()] interface. 6595** 6596** ^An attempt to read from an expired [BLOB handle] fails with an 6597** error code of [SQLITE_ABORT]. 6598** 6599** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6600** Otherwise, an [error code] or an [extended error code] is returned.)^ 6601** 6602** This routine only works on a [BLOB handle] which has been created 6603** by a prior successful call to [sqlite3_blob_open()] and which has not 6604** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6605** to this routine results in undefined and probably undesirable behavior. 6606** 6607** See also: [sqlite3_blob_write()]. 6608*/ 6609int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6610 6611/* 6612** CAPI3REF: Write Data Into A BLOB Incrementally 6613** METHOD: sqlite3_blob 6614** 6615** ^(This function is used to write data into an open [BLOB handle] from a 6616** caller-supplied buffer. N bytes of data are copied from the buffer Z 6617** into the open BLOB, starting at offset iOffset.)^ 6618** 6619** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6620** Otherwise, an [error code] or an [extended error code] is returned.)^ 6621** ^Unless SQLITE_MISUSE is returned, this function sets the 6622** [database connection] error code and message accessible via 6623** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6624** 6625** ^If the [BLOB handle] passed as the first argument was not opened for 6626** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6627** this function returns [SQLITE_READONLY]. 6628** 6629** This function may only modify the contents of the BLOB; it is 6630** not possible to increase the size of a BLOB using this API. 6631** ^If offset iOffset is less than N bytes from the end of the BLOB, 6632** [SQLITE_ERROR] is returned and no data is written. The size of the 6633** BLOB (and hence the maximum value of N+iOffset) can be determined 6634** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6635** than zero [SQLITE_ERROR] is returned and no data is written. 6636** 6637** ^An attempt to write to an expired [BLOB handle] fails with an 6638** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6639** before the [BLOB handle] expired are not rolled back by the 6640** expiration of the handle, though of course those changes might 6641** have been overwritten by the statement that expired the BLOB handle 6642** or by other independent statements. 6643** 6644** This routine only works on a [BLOB handle] which has been created 6645** by a prior successful call to [sqlite3_blob_open()] and which has not 6646** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6647** to this routine results in undefined and probably undesirable behavior. 6648** 6649** See also: [sqlite3_blob_read()]. 6650*/ 6651int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6652 6653/* 6654** CAPI3REF: Virtual File System Objects 6655** 6656** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6657** that SQLite uses to interact 6658** with the underlying operating system. Most SQLite builds come with a 6659** single default VFS that is appropriate for the host computer. 6660** New VFSes can be registered and existing VFSes can be unregistered. 6661** The following interfaces are provided. 6662** 6663** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6664** ^Names are case sensitive. 6665** ^Names are zero-terminated UTF-8 strings. 6666** ^If there is no match, a NULL pointer is returned. 6667** ^If zVfsName is NULL then the default VFS is returned. 6668** 6669** ^New VFSes are registered with sqlite3_vfs_register(). 6670** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6671** ^The same VFS can be registered multiple times without injury. 6672** ^To make an existing VFS into the default VFS, register it again 6673** with the makeDflt flag set. If two different VFSes with the 6674** same name are registered, the behavior is undefined. If a 6675** VFS is registered with a name that is NULL or an empty string, 6676** then the behavior is undefined. 6677** 6678** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6679** ^(If the default VFS is unregistered, another VFS is chosen as 6680** the default. The choice for the new VFS is arbitrary.)^ 6681*/ 6682sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6683int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6684int sqlite3_vfs_unregister(sqlite3_vfs*); 6685 6686/* 6687** CAPI3REF: Mutexes 6688** 6689** The SQLite core uses these routines for thread 6690** synchronization. Though they are intended for internal 6691** use by SQLite, code that links against SQLite is 6692** permitted to use any of these routines. 6693** 6694** The SQLite source code contains multiple implementations 6695** of these mutex routines. An appropriate implementation 6696** is selected automatically at compile-time. The following 6697** implementations are available in the SQLite core: 6698** 6699** <ul> 6700** <li> SQLITE_MUTEX_PTHREADS 6701** <li> SQLITE_MUTEX_W32 6702** <li> SQLITE_MUTEX_NOOP 6703** </ul> 6704** 6705** The SQLITE_MUTEX_NOOP implementation is a set of routines 6706** that does no real locking and is appropriate for use in 6707** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6708** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6709** and Windows. 6710** 6711** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6712** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6713** implementation is included with the library. In this case the 6714** application must supply a custom mutex implementation using the 6715** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6716** before calling sqlite3_initialize() or any other public sqlite3_ 6717** function that calls sqlite3_initialize(). 6718** 6719** ^The sqlite3_mutex_alloc() routine allocates a new 6720** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6721** routine returns NULL if it is unable to allocate the requested 6722** mutex. The argument to sqlite3_mutex_alloc() must one of these 6723** integer constants: 6724** 6725** <ul> 6726** <li> SQLITE_MUTEX_FAST 6727** <li> SQLITE_MUTEX_RECURSIVE 6728** <li> SQLITE_MUTEX_STATIC_MASTER 6729** <li> SQLITE_MUTEX_STATIC_MEM 6730** <li> SQLITE_MUTEX_STATIC_OPEN 6731** <li> SQLITE_MUTEX_STATIC_PRNG 6732** <li> SQLITE_MUTEX_STATIC_LRU 6733** <li> SQLITE_MUTEX_STATIC_PMEM 6734** <li> SQLITE_MUTEX_STATIC_APP1 6735** <li> SQLITE_MUTEX_STATIC_APP2 6736** <li> SQLITE_MUTEX_STATIC_APP3 6737** <li> SQLITE_MUTEX_STATIC_VFS1 6738** <li> SQLITE_MUTEX_STATIC_VFS2 6739** <li> SQLITE_MUTEX_STATIC_VFS3 6740** </ul> 6741** 6742** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6743** cause sqlite3_mutex_alloc() to create 6744** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6745** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6746** The mutex implementation does not need to make a distinction 6747** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6748** not want to. SQLite will only request a recursive mutex in 6749** cases where it really needs one. If a faster non-recursive mutex 6750** implementation is available on the host platform, the mutex subsystem 6751** might return such a mutex in response to SQLITE_MUTEX_FAST. 6752** 6753** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6754** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6755** a pointer to a static preexisting mutex. ^Nine static mutexes are 6756** used by the current version of SQLite. Future versions of SQLite 6757** may add additional static mutexes. Static mutexes are for internal 6758** use by SQLite only. Applications that use SQLite mutexes should 6759** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6760** SQLITE_MUTEX_RECURSIVE. 6761** 6762** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6763** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6764** returns a different mutex on every call. ^For the static 6765** mutex types, the same mutex is returned on every call that has 6766** the same type number. 6767** 6768** ^The sqlite3_mutex_free() routine deallocates a previously 6769** allocated dynamic mutex. Attempting to deallocate a static 6770** mutex results in undefined behavior. 6771** 6772** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6773** to enter a mutex. ^If another thread is already within the mutex, 6774** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6775** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6776** upon successful entry. ^(Mutexes created using 6777** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6778** In such cases, the 6779** mutex must be exited an equal number of times before another thread 6780** can enter.)^ If the same thread tries to enter any mutex other 6781** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6782** 6783** ^(Some systems (for example, Windows 95) do not support the operation 6784** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6785** will always return SQLITE_BUSY. The SQLite core only ever uses 6786** sqlite3_mutex_try() as an optimization so this is acceptable 6787** behavior.)^ 6788** 6789** ^The sqlite3_mutex_leave() routine exits a mutex that was 6790** previously entered by the same thread. The behavior 6791** is undefined if the mutex is not currently entered by the 6792** calling thread or is not currently allocated. 6793** 6794** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6795** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6796** behave as no-ops. 6797** 6798** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6799*/ 6800sqlite3_mutex *sqlite3_mutex_alloc(int); 6801void sqlite3_mutex_free(sqlite3_mutex*); 6802void sqlite3_mutex_enter(sqlite3_mutex*); 6803int sqlite3_mutex_try(sqlite3_mutex*); 6804void sqlite3_mutex_leave(sqlite3_mutex*); 6805 6806/* 6807** CAPI3REF: Mutex Methods Object 6808** 6809** An instance of this structure defines the low-level routines 6810** used to allocate and use mutexes. 6811** 6812** Usually, the default mutex implementations provided by SQLite are 6813** sufficient, however the application has the option of substituting a custom 6814** implementation for specialized deployments or systems for which SQLite 6815** does not provide a suitable implementation. In this case, the application 6816** creates and populates an instance of this structure to pass 6817** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6818** Additionally, an instance of this structure can be used as an 6819** output variable when querying the system for the current mutex 6820** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6821** 6822** ^The xMutexInit method defined by this structure is invoked as 6823** part of system initialization by the sqlite3_initialize() function. 6824** ^The xMutexInit routine is called by SQLite exactly once for each 6825** effective call to [sqlite3_initialize()]. 6826** 6827** ^The xMutexEnd method defined by this structure is invoked as 6828** part of system shutdown by the sqlite3_shutdown() function. The 6829** implementation of this method is expected to release all outstanding 6830** resources obtained by the mutex methods implementation, especially 6831** those obtained by the xMutexInit method. ^The xMutexEnd() 6832** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6833** 6834** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6835** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6836** xMutexNotheld) implement the following interfaces (respectively): 6837** 6838** <ul> 6839** <li> [sqlite3_mutex_alloc()] </li> 6840** <li> [sqlite3_mutex_free()] </li> 6841** <li> [sqlite3_mutex_enter()] </li> 6842** <li> [sqlite3_mutex_try()] </li> 6843** <li> [sqlite3_mutex_leave()] </li> 6844** <li> [sqlite3_mutex_held()] </li> 6845** <li> [sqlite3_mutex_notheld()] </li> 6846** </ul>)^ 6847** 6848** The only difference is that the public sqlite3_XXX functions enumerated 6849** above silently ignore any invocations that pass a NULL pointer instead 6850** of a valid mutex handle. The implementations of the methods defined 6851** by this structure are not required to handle this case, the results 6852** of passing a NULL pointer instead of a valid mutex handle are undefined 6853** (i.e. it is acceptable to provide an implementation that segfaults if 6854** it is passed a NULL pointer). 6855** 6856** The xMutexInit() method must be threadsafe. It must be harmless to 6857** invoke xMutexInit() multiple times within the same process and without 6858** intervening calls to xMutexEnd(). Second and subsequent calls to 6859** xMutexInit() must be no-ops. 6860** 6861** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6862** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6863** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6864** memory allocation for a fast or recursive mutex. 6865** 6866** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6867** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6868** If xMutexInit fails in any way, it is expected to clean up after itself 6869** prior to returning. 6870*/ 6871typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6872struct sqlite3_mutex_methods { 6873 int (*xMutexInit)(void); 6874 int (*xMutexEnd)(void); 6875 sqlite3_mutex *(*xMutexAlloc)(int); 6876 void (*xMutexFree)(sqlite3_mutex *); 6877 void (*xMutexEnter)(sqlite3_mutex *); 6878 int (*xMutexTry)(sqlite3_mutex *); 6879 void (*xMutexLeave)(sqlite3_mutex *); 6880 int (*xMutexHeld)(sqlite3_mutex *); 6881 int (*xMutexNotheld)(sqlite3_mutex *); 6882}; 6883 6884/* 6885** CAPI3REF: Mutex Verification Routines 6886** 6887** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6888** are intended for use inside assert() statements. The SQLite core 6889** never uses these routines except inside an assert() and applications 6890** are advised to follow the lead of the core. The SQLite core only 6891** provides implementations for these routines when it is compiled 6892** with the SQLITE_DEBUG flag. External mutex implementations 6893** are only required to provide these routines if SQLITE_DEBUG is 6894** defined and if NDEBUG is not defined. 6895** 6896** These routines should return true if the mutex in their argument 6897** is held or not held, respectively, by the calling thread. 6898** 6899** The implementation is not required to provide versions of these 6900** routines that actually work. If the implementation does not provide working 6901** versions of these routines, it should at least provide stubs that always 6902** return true so that one does not get spurious assertion failures. 6903** 6904** If the argument to sqlite3_mutex_held() is a NULL pointer then 6905** the routine should return 1. This seems counter-intuitive since 6906** clearly the mutex cannot be held if it does not exist. But 6907** the reason the mutex does not exist is because the build is not 6908** using mutexes. And we do not want the assert() containing the 6909** call to sqlite3_mutex_held() to fail, so a non-zero return is 6910** the appropriate thing to do. The sqlite3_mutex_notheld() 6911** interface should also return 1 when given a NULL pointer. 6912*/ 6913#ifndef NDEBUG 6914int sqlite3_mutex_held(sqlite3_mutex*); 6915int sqlite3_mutex_notheld(sqlite3_mutex*); 6916#endif 6917 6918/* 6919** CAPI3REF: Mutex Types 6920** 6921** The [sqlite3_mutex_alloc()] interface takes a single argument 6922** which is one of these integer constants. 6923** 6924** The set of static mutexes may change from one SQLite release to the 6925** next. Applications that override the built-in mutex logic must be 6926** prepared to accommodate additional static mutexes. 6927*/ 6928#define SQLITE_MUTEX_FAST 0 6929#define SQLITE_MUTEX_RECURSIVE 1 6930#define SQLITE_MUTEX_STATIC_MASTER 2 6931#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6932#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6933#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6934#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6935#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6936#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6937#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6938#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6939#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6940#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6941#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6942#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6943#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6944 6945/* 6946** CAPI3REF: Retrieve the mutex for a database connection 6947** METHOD: sqlite3 6948** 6949** ^This interface returns a pointer the [sqlite3_mutex] object that 6950** serializes access to the [database connection] given in the argument 6951** when the [threading mode] is Serialized. 6952** ^If the [threading mode] is Single-thread or Multi-thread then this 6953** routine returns a NULL pointer. 6954*/ 6955sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6956 6957/* 6958** CAPI3REF: Low-Level Control Of Database Files 6959** METHOD: sqlite3 6960** 6961** ^The [sqlite3_file_control()] interface makes a direct call to the 6962** xFileControl method for the [sqlite3_io_methods] object associated 6963** with a particular database identified by the second argument. ^The 6964** name of the database is "main" for the main database or "temp" for the 6965** TEMP database, or the name that appears after the AS keyword for 6966** databases that are added using the [ATTACH] SQL command. 6967** ^A NULL pointer can be used in place of "main" to refer to the 6968** main database file. 6969** ^The third and fourth parameters to this routine 6970** are passed directly through to the second and third parameters of 6971** the xFileControl method. ^The return value of the xFileControl 6972** method becomes the return value of this routine. 6973** 6974** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 6975** a pointer to the underlying [sqlite3_file] object to be written into 6976** the space pointed to by the 4th parameter. ^The [SQLITE_FCNTL_FILE_POINTER] 6977** case is a short-circuit path which does not actually invoke the 6978** underlying sqlite3_io_methods.xFileControl method. 6979** 6980** ^If the second parameter (zDbName) does not match the name of any 6981** open database file, then SQLITE_ERROR is returned. ^This error 6982** code is not remembered and will not be recalled by [sqlite3_errcode()] 6983** or [sqlite3_errmsg()]. The underlying xFileControl method might 6984** also return SQLITE_ERROR. There is no way to distinguish between 6985** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6986** xFileControl method. 6987** 6988** See also: [file control opcodes] 6989*/ 6990int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6991 6992/* 6993** CAPI3REF: Testing Interface 6994** 6995** ^The sqlite3_test_control() interface is used to read out internal 6996** state of SQLite and to inject faults into SQLite for testing 6997** purposes. ^The first parameter is an operation code that determines 6998** the number, meaning, and operation of all subsequent parameters. 6999** 7000** This interface is not for use by applications. It exists solely 7001** for verifying the correct operation of the SQLite library. Depending 7002** on how the SQLite library is compiled, this interface might not exist. 7003** 7004** The details of the operation codes, their meanings, the parameters 7005** they take, and what they do are all subject to change without notice. 7006** Unlike most of the SQLite API, this function is not guaranteed to 7007** operate consistently from one release to the next. 7008*/ 7009int sqlite3_test_control(int op, ...); 7010 7011/* 7012** CAPI3REF: Testing Interface Operation Codes 7013** 7014** These constants are the valid operation code parameters used 7015** as the first argument to [sqlite3_test_control()]. 7016** 7017** These parameters and their meanings are subject to change 7018** without notice. These values are for testing purposes only. 7019** Applications should not use any of these parameters or the 7020** [sqlite3_test_control()] interface. 7021*/ 7022#define SQLITE_TESTCTRL_FIRST 5 7023#define SQLITE_TESTCTRL_PRNG_SAVE 5 7024#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7025#define SQLITE_TESTCTRL_PRNG_RESET 7 7026#define SQLITE_TESTCTRL_BITVEC_TEST 8 7027#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7028#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7029#define SQLITE_TESTCTRL_PENDING_BYTE 11 7030#define SQLITE_TESTCTRL_ASSERT 12 7031#define SQLITE_TESTCTRL_ALWAYS 13 7032#define SQLITE_TESTCTRL_RESERVE 14 7033#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7034#define SQLITE_TESTCTRL_ISKEYWORD 16 7035#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7036#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7037#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7038#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7039#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7040#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7041#define SQLITE_TESTCTRL_BYTEORDER 22 7042#define SQLITE_TESTCTRL_ISINIT 23 7043#define SQLITE_TESTCTRL_SORTER_MMAP 24 7044#define SQLITE_TESTCTRL_IMPOSTER 25 7045#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7046#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */ 7047 7048/* 7049** CAPI3REF: SQLite Runtime Status 7050** 7051** ^These interfaces are used to retrieve runtime status information 7052** about the performance of SQLite, and optionally to reset various 7053** highwater marks. ^The first argument is an integer code for 7054** the specific parameter to measure. ^(Recognized integer codes 7055** are of the form [status parameters | SQLITE_STATUS_...].)^ 7056** ^The current value of the parameter is returned into *pCurrent. 7057** ^The highest recorded value is returned in *pHighwater. ^If the 7058** resetFlag is true, then the highest record value is reset after 7059** *pHighwater is written. ^(Some parameters do not record the highest 7060** value. For those parameters 7061** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7062** ^(Other parameters record only the highwater mark and not the current 7063** value. For these latter parameters nothing is written into *pCurrent.)^ 7064** 7065** ^The sqlite3_status() and sqlite3_status64() routines return 7066** SQLITE_OK on success and a non-zero [error code] on failure. 7067** 7068** If either the current value or the highwater mark is too large to 7069** be represented by a 32-bit integer, then the values returned by 7070** sqlite3_status() are undefined. 7071** 7072** See also: [sqlite3_db_status()] 7073*/ 7074int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7075int sqlite3_status64( 7076 int op, 7077 sqlite3_int64 *pCurrent, 7078 sqlite3_int64 *pHighwater, 7079 int resetFlag 7080); 7081 7082 7083/* 7084** CAPI3REF: Status Parameters 7085** KEYWORDS: {status parameters} 7086** 7087** These integer constants designate various run-time status parameters 7088** that can be returned by [sqlite3_status()]. 7089** 7090** <dl> 7091** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7092** <dd>This parameter is the current amount of memory checked out 7093** using [sqlite3_malloc()], either directly or indirectly. The 7094** figure includes calls made to [sqlite3_malloc()] by the application 7095** and internal memory usage by the SQLite library. Auxiliary page-cache 7096** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7097** this parameter. The amount returned is the sum of the allocation 7098** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7099** 7100** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7101** <dd>This parameter records the largest memory allocation request 7102** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7103** internal equivalents). Only the value returned in the 7104** *pHighwater parameter to [sqlite3_status()] is of interest. 7105** The value written into the *pCurrent parameter is undefined.</dd>)^ 7106** 7107** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7108** <dd>This parameter records the number of separate memory allocations 7109** currently checked out.</dd>)^ 7110** 7111** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7112** <dd>This parameter returns the number of pages used out of the 7113** [pagecache memory allocator] that was configured using 7114** [SQLITE_CONFIG_PAGECACHE]. The 7115** value returned is in pages, not in bytes.</dd>)^ 7116** 7117** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7118** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7119** <dd>This parameter returns the number of bytes of page cache 7120** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7121** buffer and where forced to overflow to [sqlite3_malloc()]. The 7122** returned value includes allocations that overflowed because they 7123** where too large (they were larger than the "sz" parameter to 7124** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7125** no space was left in the page cache.</dd>)^ 7126** 7127** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7128** <dd>This parameter records the largest memory allocation request 7129** handed to [pagecache memory allocator]. Only the value returned in the 7130** *pHighwater parameter to [sqlite3_status()] is of interest. 7131** The value written into the *pCurrent parameter is undefined.</dd>)^ 7132** 7133** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7134** <dd>No longer used.</dd> 7135** 7136** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7137** <dd>No longer used.</dd> 7138** 7139** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7140** <dd>No longer used.</dd> 7141** 7142** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7143** <dd>The *pHighwater parameter records the deepest parser stack. 7144** The *pCurrent value is undefined. The *pHighwater value is only 7145** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7146** </dl> 7147** 7148** New status parameters may be added from time to time. 7149*/ 7150#define SQLITE_STATUS_MEMORY_USED 0 7151#define SQLITE_STATUS_PAGECACHE_USED 1 7152#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7153#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7154#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7155#define SQLITE_STATUS_MALLOC_SIZE 5 7156#define SQLITE_STATUS_PARSER_STACK 6 7157#define SQLITE_STATUS_PAGECACHE_SIZE 7 7158#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7159#define SQLITE_STATUS_MALLOC_COUNT 9 7160 7161/* 7162** CAPI3REF: Database Connection Status 7163** METHOD: sqlite3 7164** 7165** ^This interface is used to retrieve runtime status information 7166** about a single [database connection]. ^The first argument is the 7167** database connection object to be interrogated. ^The second argument 7168** is an integer constant, taken from the set of 7169** [SQLITE_DBSTATUS options], that 7170** determines the parameter to interrogate. The set of 7171** [SQLITE_DBSTATUS options] is likely 7172** to grow in future releases of SQLite. 7173** 7174** ^The current value of the requested parameter is written into *pCur 7175** and the highest instantaneous value is written into *pHiwtr. ^If 7176** the resetFlg is true, then the highest instantaneous value is 7177** reset back down to the current value. 7178** 7179** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7180** non-zero [error code] on failure. 7181** 7182** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7183*/ 7184int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7185 7186/* 7187** CAPI3REF: Status Parameters for database connections 7188** KEYWORDS: {SQLITE_DBSTATUS options} 7189** 7190** These constants are the available integer "verbs" that can be passed as 7191** the second argument to the [sqlite3_db_status()] interface. 7192** 7193** New verbs may be added in future releases of SQLite. Existing verbs 7194** might be discontinued. Applications should check the return code from 7195** [sqlite3_db_status()] to make sure that the call worked. 7196** The [sqlite3_db_status()] interface will return a non-zero error code 7197** if a discontinued or unsupported verb is invoked. 7198** 7199** <dl> 7200** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7201** <dd>This parameter returns the number of lookaside memory slots currently 7202** checked out.</dd>)^ 7203** 7204** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7205** <dd>This parameter returns the number malloc attempts that were 7206** satisfied using lookaside memory. Only the high-water value is meaningful; 7207** the current value is always zero.)^ 7208** 7209** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7210** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7211** <dd>This parameter returns the number malloc attempts that might have 7212** been satisfied using lookaside memory but failed due to the amount of 7213** memory requested being larger than the lookaside slot size. 7214** Only the high-water value is meaningful; 7215** the current value is always zero.)^ 7216** 7217** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7218** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7219** <dd>This parameter returns the number malloc attempts that might have 7220** been satisfied using lookaside memory but failed due to all lookaside 7221** memory already being in use. 7222** Only the high-water value is meaningful; 7223** the current value is always zero.)^ 7224** 7225** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7226** <dd>This parameter returns the approximate number of bytes of heap 7227** memory used by all pager caches associated with the database connection.)^ 7228** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7229** 7230** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7231** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7232** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7233** pager cache is shared between two or more connections the bytes of heap 7234** memory used by that pager cache is divided evenly between the attached 7235** connections.)^ In other words, if none of the pager caches associated 7236** with the database connection are shared, this request returns the same 7237** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7238** shared, the value returned by this call will be smaller than that returned 7239** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7240** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7241** 7242** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7243** <dd>This parameter returns the approximate number of bytes of heap 7244** memory used to store the schema for all databases associated 7245** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7246** ^The full amount of memory used by the schemas is reported, even if the 7247** schema memory is shared with other database connections due to 7248** [shared cache mode] being enabled. 7249** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7250** 7251** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7252** <dd>This parameter returns the approximate number of bytes of heap 7253** and lookaside memory used by all prepared statements associated with 7254** the database connection.)^ 7255** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7256** </dd> 7257** 7258** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7259** <dd>This parameter returns the number of pager cache hits that have 7260** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7261** is always 0. 7262** </dd> 7263** 7264** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7265** <dd>This parameter returns the number of pager cache misses that have 7266** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7267** is always 0. 7268** </dd> 7269** 7270** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7271** <dd>This parameter returns the number of dirty cache entries that have 7272** been written to disk. Specifically, the number of pages written to the 7273** wal file in wal mode databases, or the number of pages written to the 7274** database file in rollback mode databases. Any pages written as part of 7275** transaction rollback or database recovery operations are not included. 7276** If an IO or other error occurs while writing a page to disk, the effect 7277** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7278** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7279** </dd> 7280** 7281** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7282** <dd>This parameter returns zero for the current value if and only if 7283** all foreign key constraints (deferred or immediate) have been 7284** resolved.)^ ^The highwater mark is always 0. 7285** </dd> 7286** </dl> 7287*/ 7288#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7289#define SQLITE_DBSTATUS_CACHE_USED 1 7290#define SQLITE_DBSTATUS_SCHEMA_USED 2 7291#define SQLITE_DBSTATUS_STMT_USED 3 7292#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7293#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7294#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7295#define SQLITE_DBSTATUS_CACHE_HIT 7 7296#define SQLITE_DBSTATUS_CACHE_MISS 8 7297#define SQLITE_DBSTATUS_CACHE_WRITE 9 7298#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7299#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7300#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7301 7302 7303/* 7304** CAPI3REF: Prepared Statement Status 7305** METHOD: sqlite3_stmt 7306** 7307** ^(Each prepared statement maintains various 7308** [SQLITE_STMTSTATUS counters] that measure the number 7309** of times it has performed specific operations.)^ These counters can 7310** be used to monitor the performance characteristics of the prepared 7311** statements. For example, if the number of table steps greatly exceeds 7312** the number of table searches or result rows, that would tend to indicate 7313** that the prepared statement is using a full table scan rather than 7314** an index. 7315** 7316** ^(This interface is used to retrieve and reset counter values from 7317** a [prepared statement]. The first argument is the prepared statement 7318** object to be interrogated. The second argument 7319** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7320** to be interrogated.)^ 7321** ^The current value of the requested counter is returned. 7322** ^If the resetFlg is true, then the counter is reset to zero after this 7323** interface call returns. 7324** 7325** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7326*/ 7327int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7328 7329/* 7330** CAPI3REF: Status Parameters for prepared statements 7331** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7332** 7333** These preprocessor macros define integer codes that name counter 7334** values associated with the [sqlite3_stmt_status()] interface. 7335** The meanings of the various counters are as follows: 7336** 7337** <dl> 7338** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7339** <dd>^This is the number of times that SQLite has stepped forward in 7340** a table as part of a full table scan. Large numbers for this counter 7341** may indicate opportunities for performance improvement through 7342** careful use of indices.</dd> 7343** 7344** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7345** <dd>^This is the number of sort operations that have occurred. 7346** A non-zero value in this counter may indicate an opportunity to 7347** improvement performance through careful use of indices.</dd> 7348** 7349** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7350** <dd>^This is the number of rows inserted into transient indices that 7351** were created automatically in order to help joins run faster. 7352** A non-zero value in this counter may indicate an opportunity to 7353** improvement performance by adding permanent indices that do not 7354** need to be reinitialized each time the statement is run.</dd> 7355** 7356** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7357** <dd>^This is the number of virtual machine operations executed 7358** by the prepared statement if that number is less than or equal 7359** to 2147483647. The number of virtual machine operations can be 7360** used as a proxy for the total work done by the prepared statement. 7361** If the number of virtual machine operations exceeds 2147483647 7362** then the value returned by this statement status code is undefined. 7363** 7364** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7365** <dd>^This is the number of times that the prepare statement has been 7366** automatically regenerated due to schema changes or change to 7367** [bound parameters] that might affect the query plan. 7368** 7369** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7370** <dd>^This is the number of times that the prepared statement has 7371** been run. A single "run" for the purposes of this counter is one 7372** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7373** The counter is incremented on the first [sqlite3_step()] call of each 7374** cycle. 7375** 7376** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7377** <dd>^This is the approximate number of bytes of heap memory 7378** used to store the prepared statement. ^This value is not actually 7379** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7380** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7381** </dd> 7382** </dl> 7383*/ 7384#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7385#define SQLITE_STMTSTATUS_SORT 2 7386#define SQLITE_STMTSTATUS_AUTOINDEX 3 7387#define SQLITE_STMTSTATUS_VM_STEP 4 7388#define SQLITE_STMTSTATUS_REPREPARE 5 7389#define SQLITE_STMTSTATUS_RUN 6 7390#define SQLITE_STMTSTATUS_MEMUSED 99 7391 7392/* 7393** CAPI3REF: Custom Page Cache Object 7394** 7395** The sqlite3_pcache type is opaque. It is implemented by 7396** the pluggable module. The SQLite core has no knowledge of 7397** its size or internal structure and never deals with the 7398** sqlite3_pcache object except by holding and passing pointers 7399** to the object. 7400** 7401** See [sqlite3_pcache_methods2] for additional information. 7402*/ 7403typedef struct sqlite3_pcache sqlite3_pcache; 7404 7405/* 7406** CAPI3REF: Custom Page Cache Object 7407** 7408** The sqlite3_pcache_page object represents a single page in the 7409** page cache. The page cache will allocate instances of this 7410** object. Various methods of the page cache use pointers to instances 7411** of this object as parameters or as their return value. 7412** 7413** See [sqlite3_pcache_methods2] for additional information. 7414*/ 7415typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7416struct sqlite3_pcache_page { 7417 void *pBuf; /* The content of the page */ 7418 void *pExtra; /* Extra information associated with the page */ 7419}; 7420 7421/* 7422** CAPI3REF: Application Defined Page Cache. 7423** KEYWORDS: {page cache} 7424** 7425** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7426** register an alternative page cache implementation by passing in an 7427** instance of the sqlite3_pcache_methods2 structure.)^ 7428** In many applications, most of the heap memory allocated by 7429** SQLite is used for the page cache. 7430** By implementing a 7431** custom page cache using this API, an application can better control 7432** the amount of memory consumed by SQLite, the way in which 7433** that memory is allocated and released, and the policies used to 7434** determine exactly which parts of a database file are cached and for 7435** how long. 7436** 7437** The alternative page cache mechanism is an 7438** extreme measure that is only needed by the most demanding applications. 7439** The built-in page cache is recommended for most uses. 7440** 7441** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7442** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7443** the application may discard the parameter after the call to 7444** [sqlite3_config()] returns.)^ 7445** 7446** [[the xInit() page cache method]] 7447** ^(The xInit() method is called once for each effective 7448** call to [sqlite3_initialize()])^ 7449** (usually only once during the lifetime of the process). ^(The xInit() 7450** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7451** The intent of the xInit() method is to set up global data structures 7452** required by the custom page cache implementation. 7453** ^(If the xInit() method is NULL, then the 7454** built-in default page cache is used instead of the application defined 7455** page cache.)^ 7456** 7457** [[the xShutdown() page cache method]] 7458** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7459** It can be used to clean up 7460** any outstanding resources before process shutdown, if required. 7461** ^The xShutdown() method may be NULL. 7462** 7463** ^SQLite automatically serializes calls to the xInit method, 7464** so the xInit method need not be threadsafe. ^The 7465** xShutdown method is only called from [sqlite3_shutdown()] so it does 7466** not need to be threadsafe either. All other methods must be threadsafe 7467** in multithreaded applications. 7468** 7469** ^SQLite will never invoke xInit() more than once without an intervening 7470** call to xShutdown(). 7471** 7472** [[the xCreate() page cache methods]] 7473** ^SQLite invokes the xCreate() method to construct a new cache instance. 7474** SQLite will typically create one cache instance for each open database file, 7475** though this is not guaranteed. ^The 7476** first parameter, szPage, is the size in bytes of the pages that must 7477** be allocated by the cache. ^szPage will always a power of two. ^The 7478** second parameter szExtra is a number of bytes of extra storage 7479** associated with each page cache entry. ^The szExtra parameter will 7480** a number less than 250. SQLite will use the 7481** extra szExtra bytes on each page to store metadata about the underlying 7482** database page on disk. The value passed into szExtra depends 7483** on the SQLite version, the target platform, and how SQLite was compiled. 7484** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7485** created will be used to cache database pages of a file stored on disk, or 7486** false if it is used for an in-memory database. The cache implementation 7487** does not have to do anything special based with the value of bPurgeable; 7488** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7489** never invoke xUnpin() except to deliberately delete a page. 7490** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7491** false will always have the "discard" flag set to true. 7492** ^Hence, a cache created with bPurgeable false will 7493** never contain any unpinned pages. 7494** 7495** [[the xCachesize() page cache method]] 7496** ^(The xCachesize() method may be called at any time by SQLite to set the 7497** suggested maximum cache-size (number of pages stored by) the cache 7498** instance passed as the first argument. This is the value configured using 7499** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7500** parameter, the implementation is not required to do anything with this 7501** value; it is advisory only. 7502** 7503** [[the xPagecount() page cache methods]] 7504** The xPagecount() method must return the number of pages currently 7505** stored in the cache, both pinned and unpinned. 7506** 7507** [[the xFetch() page cache methods]] 7508** The xFetch() method locates a page in the cache and returns a pointer to 7509** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7510** The pBuf element of the returned sqlite3_pcache_page object will be a 7511** pointer to a buffer of szPage bytes used to store the content of a 7512** single database page. The pExtra element of sqlite3_pcache_page will be 7513** a pointer to the szExtra bytes of extra storage that SQLite has requested 7514** for each entry in the page cache. 7515** 7516** The page to be fetched is determined by the key. ^The minimum key value 7517** is 1. After it has been retrieved using xFetch, the page is considered 7518** to be "pinned". 7519** 7520** If the requested page is already in the page cache, then the page cache 7521** implementation must return a pointer to the page buffer with its content 7522** intact. If the requested page is not already in the cache, then the 7523** cache implementation should use the value of the createFlag 7524** parameter to help it determined what action to take: 7525** 7526** <table border=1 width=85% align=center> 7527** <tr><th> createFlag <th> Behavior when page is not already in cache 7528** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7529** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7530** Otherwise return NULL. 7531** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7532** NULL if allocating a new page is effectively impossible. 7533** </table> 7534** 7535** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7536** will only use a createFlag of 2 after a prior call with a createFlag of 1 7537** failed.)^ In between the to xFetch() calls, SQLite may 7538** attempt to unpin one or more cache pages by spilling the content of 7539** pinned pages to disk and synching the operating system disk cache. 7540** 7541** [[the xUnpin() page cache method]] 7542** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7543** as its second argument. If the third parameter, discard, is non-zero, 7544** then the page must be evicted from the cache. 7545** ^If the discard parameter is 7546** zero, then the page may be discarded or retained at the discretion of 7547** page cache implementation. ^The page cache implementation 7548** may choose to evict unpinned pages at any time. 7549** 7550** The cache must not perform any reference counting. A single 7551** call to xUnpin() unpins the page regardless of the number of prior calls 7552** to xFetch(). 7553** 7554** [[the xRekey() page cache methods]] 7555** The xRekey() method is used to change the key value associated with the 7556** page passed as the second argument. If the cache 7557** previously contains an entry associated with newKey, it must be 7558** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7559** to be pinned. 7560** 7561** When SQLite calls the xTruncate() method, the cache must discard all 7562** existing cache entries with page numbers (keys) greater than or equal 7563** to the value of the iLimit parameter passed to xTruncate(). If any 7564** of these pages are pinned, they are implicitly unpinned, meaning that 7565** they can be safely discarded. 7566** 7567** [[the xDestroy() page cache method]] 7568** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7569** All resources associated with the specified cache should be freed. ^After 7570** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7571** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7572** functions. 7573** 7574** [[the xShrink() page cache method]] 7575** ^SQLite invokes the xShrink() method when it wants the page cache to 7576** free up as much of heap memory as possible. The page cache implementation 7577** is not obligated to free any memory, but well-behaved implementations should 7578** do their best. 7579*/ 7580typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7581struct sqlite3_pcache_methods2 { 7582 int iVersion; 7583 void *pArg; 7584 int (*xInit)(void*); 7585 void (*xShutdown)(void*); 7586 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7587 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7588 int (*xPagecount)(sqlite3_pcache*); 7589 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7590 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7591 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7592 unsigned oldKey, unsigned newKey); 7593 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7594 void (*xDestroy)(sqlite3_pcache*); 7595 void (*xShrink)(sqlite3_pcache*); 7596}; 7597 7598/* 7599** This is the obsolete pcache_methods object that has now been replaced 7600** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7601** retained in the header file for backwards compatibility only. 7602*/ 7603typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7604struct sqlite3_pcache_methods { 7605 void *pArg; 7606 int (*xInit)(void*); 7607 void (*xShutdown)(void*); 7608 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7609 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7610 int (*xPagecount)(sqlite3_pcache*); 7611 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7612 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7613 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7614 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7615 void (*xDestroy)(sqlite3_pcache*); 7616}; 7617 7618 7619/* 7620** CAPI3REF: Online Backup Object 7621** 7622** The sqlite3_backup object records state information about an ongoing 7623** online backup operation. ^The sqlite3_backup object is created by 7624** a call to [sqlite3_backup_init()] and is destroyed by a call to 7625** [sqlite3_backup_finish()]. 7626** 7627** See Also: [Using the SQLite Online Backup API] 7628*/ 7629typedef struct sqlite3_backup sqlite3_backup; 7630 7631/* 7632** CAPI3REF: Online Backup API. 7633** 7634** The backup API copies the content of one database into another. 7635** It is useful either for creating backups of databases or 7636** for copying in-memory databases to or from persistent files. 7637** 7638** See Also: [Using the SQLite Online Backup API] 7639** 7640** ^SQLite holds a write transaction open on the destination database file 7641** for the duration of the backup operation. 7642** ^The source database is read-locked only while it is being read; 7643** it is not locked continuously for the entire backup operation. 7644** ^Thus, the backup may be performed on a live source database without 7645** preventing other database connections from 7646** reading or writing to the source database while the backup is underway. 7647** 7648** ^(To perform a backup operation: 7649** <ol> 7650** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7651** backup, 7652** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7653** the data between the two databases, and finally 7654** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7655** associated with the backup operation. 7656** </ol>)^ 7657** There should be exactly one call to sqlite3_backup_finish() for each 7658** successful call to sqlite3_backup_init(). 7659** 7660** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7661** 7662** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7663** [database connection] associated with the destination database 7664** and the database name, respectively. 7665** ^The database name is "main" for the main database, "temp" for the 7666** temporary database, or the name specified after the AS keyword in 7667** an [ATTACH] statement for an attached database. 7668** ^The S and M arguments passed to 7669** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7670** and database name of the source database, respectively. 7671** ^The source and destination [database connections] (parameters S and D) 7672** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7673** an error. 7674** 7675** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7676** there is already a read or read-write transaction open on the 7677** destination database. 7678** 7679** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7680** returned and an error code and error message are stored in the 7681** destination [database connection] D. 7682** ^The error code and message for the failed call to sqlite3_backup_init() 7683** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7684** [sqlite3_errmsg16()] functions. 7685** ^A successful call to sqlite3_backup_init() returns a pointer to an 7686** [sqlite3_backup] object. 7687** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7688** sqlite3_backup_finish() functions to perform the specified backup 7689** operation. 7690** 7691** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7692** 7693** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7694** the source and destination databases specified by [sqlite3_backup] object B. 7695** ^If N is negative, all remaining source pages are copied. 7696** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7697** are still more pages to be copied, then the function returns [SQLITE_OK]. 7698** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7699** from source to destination, then it returns [SQLITE_DONE]. 7700** ^If an error occurs while running sqlite3_backup_step(B,N), 7701** then an [error code] is returned. ^As well as [SQLITE_OK] and 7702** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7703** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7704** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7705** 7706** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7707** <ol> 7708** <li> the destination database was opened read-only, or 7709** <li> the destination database is using write-ahead-log journaling 7710** and the destination and source page sizes differ, or 7711** <li> the destination database is an in-memory database and the 7712** destination and source page sizes differ. 7713** </ol>)^ 7714** 7715** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7716** the [sqlite3_busy_handler | busy-handler function] 7717** is invoked (if one is specified). ^If the 7718** busy-handler returns non-zero before the lock is available, then 7719** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7720** sqlite3_backup_step() can be retried later. ^If the source 7721** [database connection] 7722** is being used to write to the source database when sqlite3_backup_step() 7723** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7724** case the call to sqlite3_backup_step() can be retried later on. ^(If 7725** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7726** [SQLITE_READONLY] is returned, then 7727** there is no point in retrying the call to sqlite3_backup_step(). These 7728** errors are considered fatal.)^ The application must accept 7729** that the backup operation has failed and pass the backup operation handle 7730** to the sqlite3_backup_finish() to release associated resources. 7731** 7732** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7733** on the destination file. ^The exclusive lock is not released until either 7734** sqlite3_backup_finish() is called or the backup operation is complete 7735** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7736** sqlite3_backup_step() obtains a [shared lock] on the source database that 7737** lasts for the duration of the sqlite3_backup_step() call. 7738** ^Because the source database is not locked between calls to 7739** sqlite3_backup_step(), the source database may be modified mid-way 7740** through the backup process. ^If the source database is modified by an 7741** external process or via a database connection other than the one being 7742** used by the backup operation, then the backup will be automatically 7743** restarted by the next call to sqlite3_backup_step(). ^If the source 7744** database is modified by the using the same database connection as is used 7745** by the backup operation, then the backup database is automatically 7746** updated at the same time. 7747** 7748** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7749** 7750** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7751** application wishes to abandon the backup operation, the application 7752** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7753** ^The sqlite3_backup_finish() interfaces releases all 7754** resources associated with the [sqlite3_backup] object. 7755** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7756** active write-transaction on the destination database is rolled back. 7757** The [sqlite3_backup] object is invalid 7758** and may not be used following a call to sqlite3_backup_finish(). 7759** 7760** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7761** sqlite3_backup_step() errors occurred, regardless or whether or not 7762** sqlite3_backup_step() completed. 7763** ^If an out-of-memory condition or IO error occurred during any prior 7764** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7765** sqlite3_backup_finish() returns the corresponding [error code]. 7766** 7767** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7768** is not a permanent error and does not affect the return value of 7769** sqlite3_backup_finish(). 7770** 7771** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7772** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7773** 7774** ^The sqlite3_backup_remaining() routine returns the number of pages still 7775** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7776** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7777** in the source database at the conclusion of the most recent 7778** sqlite3_backup_step(). 7779** ^(The values returned by these functions are only updated by 7780** sqlite3_backup_step(). If the source database is modified in a way that 7781** changes the size of the source database or the number of pages remaining, 7782** those changes are not reflected in the output of sqlite3_backup_pagecount() 7783** and sqlite3_backup_remaining() until after the next 7784** sqlite3_backup_step().)^ 7785** 7786** <b>Concurrent Usage of Database Handles</b> 7787** 7788** ^The source [database connection] may be used by the application for other 7789** purposes while a backup operation is underway or being initialized. 7790** ^If SQLite is compiled and configured to support threadsafe database 7791** connections, then the source database connection may be used concurrently 7792** from within other threads. 7793** 7794** However, the application must guarantee that the destination 7795** [database connection] is not passed to any other API (by any thread) after 7796** sqlite3_backup_init() is called and before the corresponding call to 7797** sqlite3_backup_finish(). SQLite does not currently check to see 7798** if the application incorrectly accesses the destination [database connection] 7799** and so no error code is reported, but the operations may malfunction 7800** nevertheless. Use of the destination database connection while a 7801** backup is in progress might also also cause a mutex deadlock. 7802** 7803** If running in [shared cache mode], the application must 7804** guarantee that the shared cache used by the destination database 7805** is not accessed while the backup is running. In practice this means 7806** that the application must guarantee that the disk file being 7807** backed up to is not accessed by any connection within the process, 7808** not just the specific connection that was passed to sqlite3_backup_init(). 7809** 7810** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7811** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7812** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7813** APIs are not strictly speaking threadsafe. If they are invoked at the 7814** same time as another thread is invoking sqlite3_backup_step() it is 7815** possible that they return invalid values. 7816*/ 7817sqlite3_backup *sqlite3_backup_init( 7818 sqlite3 *pDest, /* Destination database handle */ 7819 const char *zDestName, /* Destination database name */ 7820 sqlite3 *pSource, /* Source database handle */ 7821 const char *zSourceName /* Source database name */ 7822); 7823int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7824int sqlite3_backup_finish(sqlite3_backup *p); 7825int sqlite3_backup_remaining(sqlite3_backup *p); 7826int sqlite3_backup_pagecount(sqlite3_backup *p); 7827 7828/* 7829** CAPI3REF: Unlock Notification 7830** METHOD: sqlite3 7831** 7832** ^When running in shared-cache mode, a database operation may fail with 7833** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7834** individual tables within the shared-cache cannot be obtained. See 7835** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7836** ^This API may be used to register a callback that SQLite will invoke 7837** when the connection currently holding the required lock relinquishes it. 7838** ^This API is only available if the library was compiled with the 7839** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7840** 7841** See Also: [Using the SQLite Unlock Notification Feature]. 7842** 7843** ^Shared-cache locks are released when a database connection concludes 7844** its current transaction, either by committing it or rolling it back. 7845** 7846** ^When a connection (known as the blocked connection) fails to obtain a 7847** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7848** identity of the database connection (the blocking connection) that 7849** has locked the required resource is stored internally. ^After an 7850** application receives an SQLITE_LOCKED error, it may call the 7851** sqlite3_unlock_notify() method with the blocked connection handle as 7852** the first argument to register for a callback that will be invoked 7853** when the blocking connections current transaction is concluded. ^The 7854** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7855** call that concludes the blocking connections transaction. 7856** 7857** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7858** there is a chance that the blocking connection will have already 7859** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7860** If this happens, then the specified callback is invoked immediately, 7861** from within the call to sqlite3_unlock_notify().)^ 7862** 7863** ^If the blocked connection is attempting to obtain a write-lock on a 7864** shared-cache table, and more than one other connection currently holds 7865** a read-lock on the same table, then SQLite arbitrarily selects one of 7866** the other connections to use as the blocking connection. 7867** 7868** ^(There may be at most one unlock-notify callback registered by a 7869** blocked connection. If sqlite3_unlock_notify() is called when the 7870** blocked connection already has a registered unlock-notify callback, 7871** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7872** called with a NULL pointer as its second argument, then any existing 7873** unlock-notify callback is canceled. ^The blocked connections 7874** unlock-notify callback may also be canceled by closing the blocked 7875** connection using [sqlite3_close()]. 7876** 7877** The unlock-notify callback is not reentrant. If an application invokes 7878** any sqlite3_xxx API functions from within an unlock-notify callback, a 7879** crash or deadlock may be the result. 7880** 7881** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7882** returns SQLITE_OK. 7883** 7884** <b>Callback Invocation Details</b> 7885** 7886** When an unlock-notify callback is registered, the application provides a 7887** single void* pointer that is passed to the callback when it is invoked. 7888** However, the signature of the callback function allows SQLite to pass 7889** it an array of void* context pointers. The first argument passed to 7890** an unlock-notify callback is a pointer to an array of void* pointers, 7891** and the second is the number of entries in the array. 7892** 7893** When a blocking connections transaction is concluded, there may be 7894** more than one blocked connection that has registered for an unlock-notify 7895** callback. ^If two or more such blocked connections have specified the 7896** same callback function, then instead of invoking the callback function 7897** multiple times, it is invoked once with the set of void* context pointers 7898** specified by the blocked connections bundled together into an array. 7899** This gives the application an opportunity to prioritize any actions 7900** related to the set of unblocked database connections. 7901** 7902** <b>Deadlock Detection</b> 7903** 7904** Assuming that after registering for an unlock-notify callback a 7905** database waits for the callback to be issued before taking any further 7906** action (a reasonable assumption), then using this API may cause the 7907** application to deadlock. For example, if connection X is waiting for 7908** connection Y's transaction to be concluded, and similarly connection 7909** Y is waiting on connection X's transaction, then neither connection 7910** will proceed and the system may remain deadlocked indefinitely. 7911** 7912** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7913** detection. ^If a given call to sqlite3_unlock_notify() would put the 7914** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7915** unlock-notify callback is registered. The system is said to be in 7916** a deadlocked state if connection A has registered for an unlock-notify 7917** callback on the conclusion of connection B's transaction, and connection 7918** B has itself registered for an unlock-notify callback when connection 7919** A's transaction is concluded. ^Indirect deadlock is also detected, so 7920** the system is also considered to be deadlocked if connection B has 7921** registered for an unlock-notify callback on the conclusion of connection 7922** C's transaction, where connection C is waiting on connection A. ^Any 7923** number of levels of indirection are allowed. 7924** 7925** <b>The "DROP TABLE" Exception</b> 7926** 7927** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7928** always appropriate to call sqlite3_unlock_notify(). There is however, 7929** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7930** SQLite checks if there are any currently executing SELECT statements 7931** that belong to the same connection. If there are, SQLITE_LOCKED is 7932** returned. In this case there is no "blocking connection", so invoking 7933** sqlite3_unlock_notify() results in the unlock-notify callback being 7934** invoked immediately. If the application then re-attempts the "DROP TABLE" 7935** or "DROP INDEX" query, an infinite loop might be the result. 7936** 7937** One way around this problem is to check the extended error code returned 7938** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7939** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7940** the special "DROP TABLE/INDEX" case, the extended error code is just 7941** SQLITE_LOCKED.)^ 7942*/ 7943int sqlite3_unlock_notify( 7944 sqlite3 *pBlocked, /* Waiting connection */ 7945 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7946 void *pNotifyArg /* Argument to pass to xNotify */ 7947); 7948 7949 7950/* 7951** CAPI3REF: String Comparison 7952** 7953** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7954** and extensions to compare the contents of two buffers containing UTF-8 7955** strings in a case-independent fashion, using the same definition of "case 7956** independence" that SQLite uses internally when comparing identifiers. 7957*/ 7958int sqlite3_stricmp(const char *, const char *); 7959int sqlite3_strnicmp(const char *, const char *, int); 7960 7961/* 7962** CAPI3REF: String Globbing 7963* 7964** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7965** string X matches the [GLOB] pattern P. 7966** ^The definition of [GLOB] pattern matching used in 7967** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7968** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7969** is case sensitive. 7970** 7971** Note that this routine returns zero on a match and non-zero if the strings 7972** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7973** 7974** See also: [sqlite3_strlike()]. 7975*/ 7976int sqlite3_strglob(const char *zGlob, const char *zStr); 7977 7978/* 7979** CAPI3REF: String LIKE Matching 7980* 7981** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7982** string X matches the [LIKE] pattern P with escape character E. 7983** ^The definition of [LIKE] pattern matching used in 7984** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7985** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7986** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7987** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7988** insensitive - equivalent upper and lower case ASCII characters match 7989** one another. 7990** 7991** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7992** only ASCII characters are case folded. 7993** 7994** Note that this routine returns zero on a match and non-zero if the strings 7995** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7996** 7997** See also: [sqlite3_strglob()]. 7998*/ 7999int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8000 8001/* 8002** CAPI3REF: Error Logging Interface 8003** 8004** ^The [sqlite3_log()] interface writes a message into the [error log] 8005** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8006** ^If logging is enabled, the zFormat string and subsequent arguments are 8007** used with [sqlite3_snprintf()] to generate the final output string. 8008** 8009** The sqlite3_log() interface is intended for use by extensions such as 8010** virtual tables, collating functions, and SQL functions. While there is 8011** nothing to prevent an application from calling sqlite3_log(), doing so 8012** is considered bad form. 8013** 8014** The zFormat string must not be NULL. 8015** 8016** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8017** will not use dynamically allocated memory. The log message is stored in 8018** a fixed-length buffer on the stack. If the log message is longer than 8019** a few hundred characters, it will be truncated to the length of the 8020** buffer. 8021*/ 8022void sqlite3_log(int iErrCode, const char *zFormat, ...); 8023 8024/* 8025** CAPI3REF: Write-Ahead Log Commit Hook 8026** METHOD: sqlite3 8027** 8028** ^The [sqlite3_wal_hook()] function is used to register a callback that 8029** is invoked each time data is committed to a database in wal mode. 8030** 8031** ^(The callback is invoked by SQLite after the commit has taken place and 8032** the associated write-lock on the database released)^, so the implementation 8033** may read, write or [checkpoint] the database as required. 8034** 8035** ^The first parameter passed to the callback function when it is invoked 8036** is a copy of the third parameter passed to sqlite3_wal_hook() when 8037** registering the callback. ^The second is a copy of the database handle. 8038** ^The third parameter is the name of the database that was written to - 8039** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8040** is the number of pages currently in the write-ahead log file, 8041** including those that were just committed. 8042** 8043** The callback function should normally return [SQLITE_OK]. ^If an error 8044** code is returned, that error will propagate back up through the 8045** SQLite code base to cause the statement that provoked the callback 8046** to report an error, though the commit will have still occurred. If the 8047** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8048** that does not correspond to any valid SQLite error code, the results 8049** are undefined. 8050** 8051** A single database handle may have at most a single write-ahead log callback 8052** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8053** previously registered write-ahead log callback. ^Note that the 8054** [sqlite3_wal_autocheckpoint()] interface and the 8055** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8056** overwrite any prior [sqlite3_wal_hook()] settings. 8057*/ 8058void *sqlite3_wal_hook( 8059 sqlite3*, 8060 int(*)(void *,sqlite3*,const char*,int), 8061 void* 8062); 8063 8064/* 8065** CAPI3REF: Configure an auto-checkpoint 8066** METHOD: sqlite3 8067** 8068** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8069** [sqlite3_wal_hook()] that causes any database on [database connection] D 8070** to automatically [checkpoint] 8071** after committing a transaction if there are N or 8072** more frames in the [write-ahead log] file. ^Passing zero or 8073** a negative value as the nFrame parameter disables automatic 8074** checkpoints entirely. 8075** 8076** ^The callback registered by this function replaces any existing callback 8077** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8078** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8079** configured by this function. 8080** 8081** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8082** from SQL. 8083** 8084** ^Checkpoints initiated by this mechanism are 8085** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8086** 8087** ^Every new [database connection] defaults to having the auto-checkpoint 8088** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8089** pages. The use of this interface 8090** is only necessary if the default setting is found to be suboptimal 8091** for a particular application. 8092*/ 8093int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8094 8095/* 8096** CAPI3REF: Checkpoint a database 8097** METHOD: sqlite3 8098** 8099** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8100** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8101** 8102** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8103** [write-ahead log] for database X on [database connection] D to be 8104** transferred into the database file and for the write-ahead log to 8105** be reset. See the [checkpointing] documentation for addition 8106** information. 8107** 8108** This interface used to be the only way to cause a checkpoint to 8109** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8110** interface was added. This interface is retained for backwards 8111** compatibility and as a convenience for applications that need to manually 8112** start a callback but which do not need the full power (and corresponding 8113** complication) of [sqlite3_wal_checkpoint_v2()]. 8114*/ 8115int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8116 8117/* 8118** CAPI3REF: Checkpoint a database 8119** METHOD: sqlite3 8120** 8121** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8122** operation on database X of [database connection] D in mode M. Status 8123** information is written back into integers pointed to by L and C.)^ 8124** ^(The M parameter must be a valid [checkpoint mode]:)^ 8125** 8126** <dl> 8127** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8128** ^Checkpoint as many frames as possible without waiting for any database 8129** readers or writers to finish, then sync the database file if all frames 8130** in the log were checkpointed. ^The [busy-handler callback] 8131** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8132** ^On the other hand, passive mode might leave the checkpoint unfinished 8133** if there are concurrent readers or writers. 8134** 8135** <dt>SQLITE_CHECKPOINT_FULL<dd> 8136** ^This mode blocks (it invokes the 8137** [sqlite3_busy_handler|busy-handler callback]) until there is no 8138** database writer and all readers are reading from the most recent database 8139** snapshot. ^It then checkpoints all frames in the log file and syncs the 8140** database file. ^This mode blocks new database writers while it is pending, 8141** but new database readers are allowed to continue unimpeded. 8142** 8143** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8144** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8145** that after checkpointing the log file it blocks (calls the 8146** [busy-handler callback]) 8147** until all readers are reading from the database file only. ^This ensures 8148** that the next writer will restart the log file from the beginning. 8149** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8150** database writer attempts while it is pending, but does not impede readers. 8151** 8152** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8153** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8154** addition that it also truncates the log file to zero bytes just prior 8155** to a successful return. 8156** </dl> 8157** 8158** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8159** the log file or to -1 if the checkpoint could not run because 8160** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8161** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8162** log file (including any that were already checkpointed before the function 8163** was called) or to -1 if the checkpoint could not run due to an error or 8164** because the database is not in WAL mode. ^Note that upon successful 8165** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8166** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8167** 8168** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8169** any other process is running a checkpoint operation at the same time, the 8170** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8171** busy-handler configured, it will not be invoked in this case. 8172** 8173** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8174** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8175** obtained immediately, and a busy-handler is configured, it is invoked and 8176** the writer lock retried until either the busy-handler returns 0 or the lock 8177** is successfully obtained. ^The busy-handler is also invoked while waiting for 8178** database readers as described above. ^If the busy-handler returns 0 before 8179** the writer lock is obtained or while waiting for database readers, the 8180** checkpoint operation proceeds from that point in the same way as 8181** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8182** without blocking any further. ^SQLITE_BUSY is returned in this case. 8183** 8184** ^If parameter zDb is NULL or points to a zero length string, then the 8185** specified operation is attempted on all WAL databases [attached] to 8186** [database connection] db. In this case the 8187** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8188** an SQLITE_BUSY error is encountered when processing one or more of the 8189** attached WAL databases, the operation is still attempted on any remaining 8190** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8191** error occurs while processing an attached database, processing is abandoned 8192** and the error code is returned to the caller immediately. ^If no error 8193** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8194** databases, SQLITE_OK is returned. 8195** 8196** ^If database zDb is the name of an attached database that is not in WAL 8197** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8198** zDb is not NULL (or a zero length string) and is not the name of any 8199** attached database, SQLITE_ERROR is returned to the caller. 8200** 8201** ^Unless it returns SQLITE_MISUSE, 8202** the sqlite3_wal_checkpoint_v2() interface 8203** sets the error information that is queried by 8204** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8205** 8206** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8207** from SQL. 8208*/ 8209int sqlite3_wal_checkpoint_v2( 8210 sqlite3 *db, /* Database handle */ 8211 const char *zDb, /* Name of attached database (or NULL) */ 8212 int eMode, /* SQLITE_CHECKPOINT_* value */ 8213 int *pnLog, /* OUT: Size of WAL log in frames */ 8214 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8215); 8216 8217/* 8218** CAPI3REF: Checkpoint Mode Values 8219** KEYWORDS: {checkpoint mode} 8220** 8221** These constants define all valid values for the "checkpoint mode" passed 8222** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8223** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8224** meaning of each of these checkpoint modes. 8225*/ 8226#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8227#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8228#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8229#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8230 8231/* 8232** CAPI3REF: Virtual Table Interface Configuration 8233** 8234** This function may be called by either the [xConnect] or [xCreate] method 8235** of a [virtual table] implementation to configure 8236** various facets of the virtual table interface. 8237** 8238** If this interface is invoked outside the context of an xConnect or 8239** xCreate virtual table method then the behavior is undefined. 8240** 8241** At present, there is only one option that may be configured using 8242** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8243** may be added in the future. 8244*/ 8245int sqlite3_vtab_config(sqlite3*, int op, ...); 8246 8247/* 8248** CAPI3REF: Virtual Table Configuration Options 8249** 8250** These macros define the various options to the 8251** [sqlite3_vtab_config()] interface that [virtual table] implementations 8252** can use to customize and optimize their behavior. 8253** 8254** <dl> 8255** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8256** <dd>Calls of the form 8257** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8258** where X is an integer. If X is zero, then the [virtual table] whose 8259** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8260** support constraints. In this configuration (which is the default) if 8261** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8262** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8263** specified as part of the users SQL statement, regardless of the actual 8264** ON CONFLICT mode specified. 8265** 8266** If X is non-zero, then the virtual table implementation guarantees 8267** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8268** any modifications to internal or persistent data structures have been made. 8269** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8270** is able to roll back a statement or database transaction, and abandon 8271** or continue processing the current SQL statement as appropriate. 8272** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8273** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8274** had been ABORT. 8275** 8276** Virtual table implementations that are required to handle OR REPLACE 8277** must do so within the [xUpdate] method. If a call to the 8278** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8279** CONFLICT policy is REPLACE, the virtual table implementation should 8280** silently replace the appropriate rows within the xUpdate callback and 8281** return SQLITE_OK. Or, if this is not possible, it may return 8282** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8283** constraint handling. 8284** </dl> 8285*/ 8286#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8287 8288/* 8289** CAPI3REF: Determine The Virtual Table Conflict Policy 8290** 8291** This function may only be called from within a call to the [xUpdate] method 8292** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8293** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8294** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8295** of the SQL statement that triggered the call to the [xUpdate] method of the 8296** [virtual table]. 8297*/ 8298int sqlite3_vtab_on_conflict(sqlite3 *); 8299 8300/* 8301** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8302** 8303** This function may only be called from within a call to the [xBestIndex] 8304** method of a [virtual table]. 8305** 8306** The first argument must be the sqlite3_index_info object that is the 8307** first parameter to the xBestIndex() method. The second argument must be 8308** an index into the aConstraint[] array belonging to the sqlite3_index_info 8309** structure passed to xBestIndex. This function returns a pointer to a buffer 8310** containing the name of the collation sequence for the corresponding 8311** constraint. 8312*/ 8313SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8314 8315/* 8316** CAPI3REF: Conflict resolution modes 8317** KEYWORDS: {conflict resolution mode} 8318** 8319** These constants are returned by [sqlite3_vtab_on_conflict()] to 8320** inform a [virtual table] implementation what the [ON CONFLICT] mode 8321** is for the SQL statement being evaluated. 8322** 8323** Note that the [SQLITE_IGNORE] constant is also used as a potential 8324** return value from the [sqlite3_set_authorizer()] callback and that 8325** [SQLITE_ABORT] is also a [result code]. 8326*/ 8327#define SQLITE_ROLLBACK 1 8328/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8329#define SQLITE_FAIL 3 8330/* #define SQLITE_ABORT 4 // Also an error code */ 8331#define SQLITE_REPLACE 5 8332 8333/* 8334** CAPI3REF: Prepared Statement Scan Status Opcodes 8335** KEYWORDS: {scanstatus options} 8336** 8337** The following constants can be used for the T parameter to the 8338** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8339** different metric for sqlite3_stmt_scanstatus() to return. 8340** 8341** When the value returned to V is a string, space to hold that string is 8342** managed by the prepared statement S and will be automatically freed when 8343** S is finalized. 8344** 8345** <dl> 8346** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8347** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8348** set to the total number of times that the X-th loop has run.</dd> 8349** 8350** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8351** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8352** to the total number of rows examined by all iterations of the X-th loop.</dd> 8353** 8354** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8355** <dd>^The "double" variable pointed to by the T parameter will be set to the 8356** query planner's estimate for the average number of rows output from each 8357** iteration of the X-th loop. If the query planner's estimates was accurate, 8358** then this value will approximate the quotient NVISIT/NLOOP and the 8359** product of this value for all prior loops with the same SELECTID will 8360** be the NLOOP value for the current loop. 8361** 8362** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8363** <dd>^The "const char *" variable pointed to by the T parameter will be set 8364** to a zero-terminated UTF-8 string containing the name of the index or table 8365** used for the X-th loop. 8366** 8367** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8368** <dd>^The "const char *" variable pointed to by the T parameter will be set 8369** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8370** description for the X-th loop. 8371** 8372** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8373** <dd>^The "int" variable pointed to by the T parameter will be set to the 8374** "select-id" for the X-th loop. The select-id identifies which query or 8375** subquery the loop is part of. The main query has a select-id of zero. 8376** The select-id is the same value as is output in the first column 8377** of an [EXPLAIN QUERY PLAN] query. 8378** </dl> 8379*/ 8380#define SQLITE_SCANSTAT_NLOOP 0 8381#define SQLITE_SCANSTAT_NVISIT 1 8382#define SQLITE_SCANSTAT_EST 2 8383#define SQLITE_SCANSTAT_NAME 3 8384#define SQLITE_SCANSTAT_EXPLAIN 4 8385#define SQLITE_SCANSTAT_SELECTID 5 8386 8387/* 8388** CAPI3REF: Prepared Statement Scan Status 8389** METHOD: sqlite3_stmt 8390** 8391** This interface returns information about the predicted and measured 8392** performance for pStmt. Advanced applications can use this 8393** interface to compare the predicted and the measured performance and 8394** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8395** 8396** Since this interface is expected to be rarely used, it is only 8397** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8398** compile-time option. 8399** 8400** The "iScanStatusOp" parameter determines which status information to return. 8401** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8402** of this interface is undefined. 8403** ^The requested measurement is written into a variable pointed to by 8404** the "pOut" parameter. 8405** Parameter "idx" identifies the specific loop to retrieve statistics for. 8406** Loops are numbered starting from zero. ^If idx is out of range - less than 8407** zero or greater than or equal to the total number of loops used to implement 8408** the statement - a non-zero value is returned and the variable that pOut 8409** points to is unchanged. 8410** 8411** ^Statistics might not be available for all loops in all statements. ^In cases 8412** where there exist loops with no available statistics, this function behaves 8413** as if the loop did not exist - it returns non-zero and leave the variable 8414** that pOut points to unchanged. 8415** 8416** See also: [sqlite3_stmt_scanstatus_reset()] 8417*/ 8418int sqlite3_stmt_scanstatus( 8419 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8420 int idx, /* Index of loop to report on */ 8421 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8422 void *pOut /* Result written here */ 8423); 8424 8425/* 8426** CAPI3REF: Zero Scan-Status Counters 8427** METHOD: sqlite3_stmt 8428** 8429** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8430** 8431** This API is only available if the library is built with pre-processor 8432** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8433*/ 8434void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8435 8436/* 8437** CAPI3REF: Flush caches to disk mid-transaction 8438** 8439** ^If a write-transaction is open on [database connection] D when the 8440** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8441** pages in the pager-cache that are not currently in use are written out 8442** to disk. A dirty page may be in use if a database cursor created by an 8443** active SQL statement is reading from it, or if it is page 1 of a database 8444** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8445** interface flushes caches for all schemas - "main", "temp", and 8446** any [attached] databases. 8447** 8448** ^If this function needs to obtain extra database locks before dirty pages 8449** can be flushed to disk, it does so. ^If those locks cannot be obtained 8450** immediately and there is a busy-handler callback configured, it is invoked 8451** in the usual manner. ^If the required lock still cannot be obtained, then 8452** the database is skipped and an attempt made to flush any dirty pages 8453** belonging to the next (if any) database. ^If any databases are skipped 8454** because locks cannot be obtained, but no other error occurs, this 8455** function returns SQLITE_BUSY. 8456** 8457** ^If any other error occurs while flushing dirty pages to disk (for 8458** example an IO error or out-of-memory condition), then processing is 8459** abandoned and an SQLite [error code] is returned to the caller immediately. 8460** 8461** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8462** 8463** ^This function does not set the database handle error code or message 8464** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8465*/ 8466int sqlite3_db_cacheflush(sqlite3*); 8467 8468/* 8469** CAPI3REF: The pre-update hook. 8470** 8471** ^These interfaces are only available if SQLite is compiled using the 8472** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8473** 8474** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8475** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8476** on a database table. 8477** ^At most one preupdate hook may be registered at a time on a single 8478** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8479** the previous setting. 8480** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8481** with a NULL pointer as the second parameter. 8482** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8483** the first parameter to callbacks. 8484** 8485** ^The preupdate hook only fires for changes to real database tables; the 8486** preupdate hook is not invoked for changes to [virtual tables] or to 8487** system tables like sqlite_master or sqlite_stat1. 8488** 8489** ^The second parameter to the preupdate callback is a pointer to 8490** the [database connection] that registered the preupdate hook. 8491** ^The third parameter to the preupdate callback is one of the constants 8492** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8493** kind of update operation that is about to occur. 8494** ^(The fourth parameter to the preupdate callback is the name of the 8495** database within the database connection that is being modified. This 8496** will be "main" for the main database or "temp" for TEMP tables or 8497** the name given after the AS keyword in the [ATTACH] statement for attached 8498** databases.)^ 8499** ^The fifth parameter to the preupdate callback is the name of the 8500** table that is being modified. 8501** 8502** For an UPDATE or DELETE operation on a [rowid table], the sixth 8503** parameter passed to the preupdate callback is the initial [rowid] of the 8504** row being modified or deleted. For an INSERT operation on a rowid table, 8505** or any operation on a WITHOUT ROWID table, the value of the sixth 8506** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8507** seventh parameter is the final rowid value of the row being inserted 8508** or updated. The value of the seventh parameter passed to the callback 8509** function is not defined for operations on WITHOUT ROWID tables, or for 8510** INSERT operations on rowid tables. 8511** 8512** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8513** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8514** provide additional information about a preupdate event. These routines 8515** may only be called from within a preupdate callback. Invoking any of 8516** these routines from outside of a preupdate callback or with a 8517** [database connection] pointer that is different from the one supplied 8518** to the preupdate callback results in undefined and probably undesirable 8519** behavior. 8520** 8521** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8522** in the row that is being inserted, updated, or deleted. 8523** 8524** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8525** a [protected sqlite3_value] that contains the value of the Nth column of 8526** the table row before it is updated. The N parameter must be between 0 8527** and one less than the number of columns or the behavior will be 8528** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8529** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8530** behavior is undefined. The [sqlite3_value] that P points to 8531** will be destroyed when the preupdate callback returns. 8532** 8533** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8534** a [protected sqlite3_value] that contains the value of the Nth column of 8535** the table row after it is updated. The N parameter must be between 0 8536** and one less than the number of columns or the behavior will be 8537** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8538** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8539** behavior is undefined. The [sqlite3_value] that P points to 8540** will be destroyed when the preupdate callback returns. 8541** 8542** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8543** callback was invoked as a result of a direct insert, update, or delete 8544** operation; or 1 for inserts, updates, or deletes invoked by top-level 8545** triggers; or 2 for changes resulting from triggers called by top-level 8546** triggers; and so forth. 8547** 8548** See also: [sqlite3_update_hook()] 8549*/ 8550#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8551void *sqlite3_preupdate_hook( 8552 sqlite3 *db, 8553 void(*xPreUpdate)( 8554 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8555 sqlite3 *db, /* Database handle */ 8556 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8557 char const *zDb, /* Database name */ 8558 char const *zName, /* Table name */ 8559 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8560 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8561 ), 8562 void* 8563); 8564int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8565int sqlite3_preupdate_count(sqlite3 *); 8566int sqlite3_preupdate_depth(sqlite3 *); 8567int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8568#endif 8569 8570/* 8571** CAPI3REF: Low-level system error code 8572** 8573** ^Attempt to return the underlying operating system error code or error 8574** number that caused the most recent I/O error or failure to open a file. 8575** The return value is OS-dependent. For example, on unix systems, after 8576** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8577** called to get back the underlying "errno" that caused the problem, such 8578** as ENOSPC, EAUTH, EISDIR, and so forth. 8579*/ 8580int sqlite3_system_errno(sqlite3*); 8581 8582/* 8583** CAPI3REF: Database Snapshot 8584** KEYWORDS: {snapshot} {sqlite3_snapshot} 8585** EXPERIMENTAL 8586** 8587** An instance of the snapshot object records the state of a [WAL mode] 8588** database for some specific point in history. 8589** 8590** In [WAL mode], multiple [database connections] that are open on the 8591** same database file can each be reading a different historical version 8592** of the database file. When a [database connection] begins a read 8593** transaction, that connection sees an unchanging copy of the database 8594** as it existed for the point in time when the transaction first started. 8595** Subsequent changes to the database from other connections are not seen 8596** by the reader until a new read transaction is started. 8597** 8598** The sqlite3_snapshot object records state information about an historical 8599** version of the database file so that it is possible to later open a new read 8600** transaction that sees that historical version of the database rather than 8601** the most recent version. 8602** 8603** The constructor for this object is [sqlite3_snapshot_get()]. The 8604** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8605** to an historical snapshot (if possible). The destructor for 8606** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8607*/ 8608typedef struct sqlite3_snapshot { 8609 unsigned char hidden[48]; 8610} sqlite3_snapshot; 8611 8612/* 8613** CAPI3REF: Record A Database Snapshot 8614** EXPERIMENTAL 8615** 8616** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8617** new [sqlite3_snapshot] object that records the current state of 8618** schema S in database connection D. ^On success, the 8619** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8620** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8621** If there is not already a read-transaction open on schema S when 8622** this function is called, one is opened automatically. 8623** 8624** The following must be true for this function to succeed. If any of 8625** the following statements are false when sqlite3_snapshot_get() is 8626** called, SQLITE_ERROR is returned. The final value of *P is undefined 8627** in this case. 8628** 8629** <ul> 8630** <li> The database handle must be in [autocommit mode]. 8631** 8632** <li> Schema S of [database connection] D must be a [WAL mode] database. 8633** 8634** <li> There must not be a write transaction open on schema S of database 8635** connection D. 8636** 8637** <li> One or more transactions must have been written to the current wal 8638** file since it was created on disk (by any connection). This means 8639** that a snapshot cannot be taken on a wal mode database with no wal 8640** file immediately after it is first opened. At least one transaction 8641** must be written to it first. 8642** </ul> 8643** 8644** This function may also return SQLITE_NOMEM. If it is called with the 8645** database handle in autocommit mode but fails for some other reason, 8646** whether or not a read transaction is opened on schema S is undefined. 8647** 8648** The [sqlite3_snapshot] object returned from a successful call to 8649** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8650** to avoid a memory leak. 8651** 8652** The [sqlite3_snapshot_get()] interface is only available when the 8653** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8654*/ 8655SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8656 sqlite3 *db, 8657 const char *zSchema, 8658 sqlite3_snapshot **ppSnapshot 8659); 8660 8661/* 8662** CAPI3REF: Start a read transaction on an historical snapshot 8663** EXPERIMENTAL 8664** 8665** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8666** read transaction for schema S of 8667** [database connection] D such that the read transaction 8668** refers to historical [snapshot] P, rather than the most 8669** recent change to the database. 8670** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8671** or an appropriate [error code] if it fails. 8672** 8673** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8674** the first operation following the [BEGIN] that takes the schema S 8675** out of [autocommit mode]. 8676** ^In other words, schema S must not currently be in 8677** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8678** database connection D must be out of [autocommit mode]. 8679** ^A [snapshot] will fail to open if it has been overwritten by a 8680** [checkpoint]. 8681** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8682** database connection D does not know that the database file for 8683** schema S is in [WAL mode]. A database connection might not know 8684** that the database file is in [WAL mode] if there has been no prior 8685** I/O on that database connection, or if the database entered [WAL mode] 8686** after the most recent I/O on the database connection.)^ 8687** (Hint: Run "[PRAGMA application_id]" against a newly opened 8688** database connection in order to make it ready to use snapshots.) 8689** 8690** The [sqlite3_snapshot_open()] interface is only available when the 8691** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8692*/ 8693SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8694 sqlite3 *db, 8695 const char *zSchema, 8696 sqlite3_snapshot *pSnapshot 8697); 8698 8699/* 8700** CAPI3REF: Destroy a snapshot 8701** EXPERIMENTAL 8702** 8703** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8704** The application must eventually free every [sqlite3_snapshot] object 8705** using this routine to avoid a memory leak. 8706** 8707** The [sqlite3_snapshot_free()] interface is only available when the 8708** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8709*/ 8710SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8711 8712/* 8713** CAPI3REF: Compare the ages of two snapshot handles. 8714** EXPERIMENTAL 8715** 8716** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8717** of two valid snapshot handles. 8718** 8719** If the two snapshot handles are not associated with the same database 8720** file, the result of the comparison is undefined. 8721** 8722** Additionally, the result of the comparison is only valid if both of the 8723** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8724** last time the wal file was deleted. The wal file is deleted when the 8725** database is changed back to rollback mode or when the number of database 8726** clients drops to zero. If either snapshot handle was obtained before the 8727** wal file was last deleted, the value returned by this function 8728** is undefined. 8729** 8730** Otherwise, this API returns a negative value if P1 refers to an older 8731** snapshot than P2, zero if the two handles refer to the same database 8732** snapshot, and a positive value if P1 is a newer snapshot than P2. 8733*/ 8734SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8735 sqlite3_snapshot *p1, 8736 sqlite3_snapshot *p2 8737); 8738 8739/* 8740** CAPI3REF: Recover snapshots from a wal file 8741** EXPERIMENTAL 8742** 8743** If all connections disconnect from a database file but do not perform 8744** a checkpoint, the existing wal file is opened along with the database 8745** file the next time the database is opened. At this point it is only 8746** possible to successfully call sqlite3_snapshot_open() to open the most 8747** recent snapshot of the database (the one at the head of the wal file), 8748** even though the wal file may contain other valid snapshots for which 8749** clients have sqlite3_snapshot handles. 8750** 8751** This function attempts to scan the wal file associated with database zDb 8752** of database handle db and make all valid snapshots available to 8753** sqlite3_snapshot_open(). It is an error if there is already a read 8754** transaction open on the database, or if the database is not a wal mode 8755** database. 8756** 8757** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8758*/ 8759SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8760 8761/* 8762** Undo the hack that converts floating point types to integer for 8763** builds on processors without floating point support. 8764*/ 8765#ifdef SQLITE_OMIT_FLOATING_POINT 8766# undef double 8767#endif 8768 8769#ifdef __cplusplus 8770} /* End of the 'extern "C"' block */ 8771#endif 8772#endif /* SQLITE3_H */ 8773