1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#endif 193 194/* 195** CAPI3REF: Test To See If The Library Is Threadsafe 196** 197** ^The sqlite3_threadsafe() function returns zero if and only if 198** SQLite was compiled with mutexing code omitted due to the 199** [SQLITE_THREADSAFE] compile-time option being set to 0. 200** 201** SQLite can be compiled with or without mutexes. When 202** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 203** are enabled and SQLite is threadsafe. When the 204** [SQLITE_THREADSAFE] macro is 0, 205** the mutexes are omitted. Without the mutexes, it is not safe 206** to use SQLite concurrently from more than one thread. 207** 208** Enabling mutexes incurs a measurable performance penalty. 209** So if speed is of utmost importance, it makes sense to disable 210** the mutexes. But for maximum safety, mutexes should be enabled. 211** ^The default behavior is for mutexes to be enabled. 212** 213** This interface can be used by an application to make sure that the 214** version of SQLite that it is linking against was compiled with 215** the desired setting of the [SQLITE_THREADSAFE] macro. 216** 217** This interface only reports on the compile-time mutex setting 218** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 219** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 220** can be fully or partially disabled using a call to [sqlite3_config()] 221** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 222** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 223** sqlite3_threadsafe() function shows only the compile-time setting of 224** thread safety, not any run-time changes to that setting made by 225** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 226** is unchanged by calls to sqlite3_config().)^ 227** 228** See the [threading mode] documentation for additional information. 229*/ 230int sqlite3_threadsafe(void); 231 232/* 233** CAPI3REF: Database Connection Handle 234** KEYWORDS: {database connection} {database connections} 235** 236** Each open SQLite database is represented by a pointer to an instance of 237** the opaque structure named "sqlite3". It is useful to think of an sqlite3 238** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 239** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 240** and [sqlite3_close_v2()] are its destructors. There are many other 241** interfaces (such as 242** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 243** [sqlite3_busy_timeout()] to name but three) that are methods on an 244** sqlite3 object. 245*/ 246typedef struct sqlite3 sqlite3; 247 248/* 249** CAPI3REF: 64-Bit Integer Types 250** KEYWORDS: sqlite_int64 sqlite_uint64 251** 252** Because there is no cross-platform way to specify 64-bit integer types 253** SQLite includes typedefs for 64-bit signed and unsigned integers. 254** 255** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 256** The sqlite_int64 and sqlite_uint64 types are supported for backwards 257** compatibility only. 258** 259** ^The sqlite3_int64 and sqlite_int64 types can store integer values 260** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 261** sqlite3_uint64 and sqlite_uint64 types can store integer values 262** between 0 and +18446744073709551615 inclusive. 263*/ 264#ifdef SQLITE_INT64_TYPE 265 typedef SQLITE_INT64_TYPE sqlite_int64; 266# ifdef SQLITE_UINT64_TYPE 267 typedef SQLITE_UINT64_TYPE sqlite_uint64; 268# else 269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 270# endif 271#elif defined(_MSC_VER) || defined(__BORLANDC__) 272 typedef __int64 sqlite_int64; 273 typedef unsigned __int64 sqlite_uint64; 274#else 275 typedef long long int sqlite_int64; 276 typedef unsigned long long int sqlite_uint64; 277#endif 278typedef sqlite_int64 sqlite3_int64; 279typedef sqlite_uint64 sqlite3_uint64; 280 281/* 282** If compiling for a processor that lacks floating point support, 283** substitute integer for floating-point. 284*/ 285#ifdef SQLITE_OMIT_FLOATING_POINT 286# define double sqlite3_int64 287#endif 288 289/* 290** CAPI3REF: Closing A Database Connection 291** DESTRUCTOR: sqlite3 292** 293** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 294** for the [sqlite3] object. 295** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 296** the [sqlite3] object is successfully destroyed and all associated 297** resources are deallocated. 298** 299** ^If the database connection is associated with unfinalized prepared 300** statements or unfinished sqlite3_backup objects then sqlite3_close() 301** will leave the database connection open and return [SQLITE_BUSY]. 302** ^If sqlite3_close_v2() is called with unfinalized prepared statements 303** and/or unfinished sqlite3_backups, then the database connection becomes 304** an unusable "zombie" which will automatically be deallocated when the 305** last prepared statement is finalized or the last sqlite3_backup is 306** finished. The sqlite3_close_v2() interface is intended for use with 307** host languages that are garbage collected, and where the order in which 308** destructors are called is arbitrary. 309** 310** Applications should [sqlite3_finalize | finalize] all [prepared statements], 311** [sqlite3_blob_close | close] all [BLOB handles], and 312** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 313** with the [sqlite3] object prior to attempting to close the object. ^If 314** sqlite3_close_v2() is called on a [database connection] that still has 315** outstanding [prepared statements], [BLOB handles], and/or 316** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 317** of resources is deferred until all [prepared statements], [BLOB handles], 318** and [sqlite3_backup] objects are also destroyed. 319** 320** ^If an [sqlite3] object is destroyed while a transaction is open, 321** the transaction is automatically rolled back. 322** 323** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 324** must be either a NULL 325** pointer or an [sqlite3] object pointer obtained 326** from [sqlite3_open()], [sqlite3_open16()], or 327** [sqlite3_open_v2()], and not previously closed. 328** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 329** argument is a harmless no-op. 330*/ 331int sqlite3_close(sqlite3*); 332int sqlite3_close_v2(sqlite3*); 333 334/* 335** The type for a callback function. 336** This is legacy and deprecated. It is included for historical 337** compatibility and is not documented. 338*/ 339typedef int (*sqlite3_callback)(void*,int,char**, char**); 340 341/* 342** CAPI3REF: One-Step Query Execution Interface 343** METHOD: sqlite3 344** 345** The sqlite3_exec() interface is a convenience wrapper around 346** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 347** that allows an application to run multiple statements of SQL 348** without having to use a lot of C code. 349** 350** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 351** semicolon-separate SQL statements passed into its 2nd argument, 352** in the context of the [database connection] passed in as its 1st 353** argument. ^If the callback function of the 3rd argument to 354** sqlite3_exec() is not NULL, then it is invoked for each result row 355** coming out of the evaluated SQL statements. ^The 4th argument to 356** sqlite3_exec() is relayed through to the 1st argument of each 357** callback invocation. ^If the callback pointer to sqlite3_exec() 358** is NULL, then no callback is ever invoked and result rows are 359** ignored. 360** 361** ^If an error occurs while evaluating the SQL statements passed into 362** sqlite3_exec(), then execution of the current statement stops and 363** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 364** is not NULL then any error message is written into memory obtained 365** from [sqlite3_malloc()] and passed back through the 5th parameter. 366** To avoid memory leaks, the application should invoke [sqlite3_free()] 367** on error message strings returned through the 5th parameter of 368** sqlite3_exec() after the error message string is no longer needed. 369** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 370** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 371** NULL before returning. 372** 373** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 374** routine returns SQLITE_ABORT without invoking the callback again and 375** without running any subsequent SQL statements. 376** 377** ^The 2nd argument to the sqlite3_exec() callback function is the 378** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 379** callback is an array of pointers to strings obtained as if from 380** [sqlite3_column_text()], one for each column. ^If an element of a 381** result row is NULL then the corresponding string pointer for the 382** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 383** sqlite3_exec() callback is an array of pointers to strings where each 384** entry represents the name of corresponding result column as obtained 385** from [sqlite3_column_name()]. 386** 387** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 388** to an empty string, or a pointer that contains only whitespace and/or 389** SQL comments, then no SQL statements are evaluated and the database 390** is not changed. 391** 392** Restrictions: 393** 394** <ul> 395** <li> The application must ensure that the 1st parameter to sqlite3_exec() 396** is a valid and open [database connection]. 397** <li> The application must not close the [database connection] specified by 398** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 399** <li> The application must not modify the SQL statement text passed into 400** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 401** </ul> 402*/ 403int sqlite3_exec( 404 sqlite3*, /* An open database */ 405 const char *sql, /* SQL to be evaluated */ 406 int (*callback)(void*,int,char**,char**), /* Callback function */ 407 void *, /* 1st argument to callback */ 408 char **errmsg /* Error msg written here */ 409); 410 411/* 412** CAPI3REF: Result Codes 413** KEYWORDS: {result code definitions} 414** 415** Many SQLite functions return an integer result code from the set shown 416** here in order to indicate success or failure. 417** 418** New error codes may be added in future versions of SQLite. 419** 420** See also: [extended result code definitions] 421*/ 422#define SQLITE_OK 0 /* Successful result */ 423/* beginning-of-error-codes */ 424#define SQLITE_ERROR 1 /* Generic error */ 425#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 426#define SQLITE_PERM 3 /* Access permission denied */ 427#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 428#define SQLITE_BUSY 5 /* The database file is locked */ 429#define SQLITE_LOCKED 6 /* A table in the database is locked */ 430#define SQLITE_NOMEM 7 /* A malloc() failed */ 431#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 432#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 433#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 434#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 435#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 436#define SQLITE_FULL 13 /* Insertion failed because database is full */ 437#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 438#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 439#define SQLITE_EMPTY 16 /* Internal use only */ 440#define SQLITE_SCHEMA 17 /* The database schema changed */ 441#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 442#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 443#define SQLITE_MISMATCH 20 /* Data type mismatch */ 444#define SQLITE_MISUSE 21 /* Library used incorrectly */ 445#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 446#define SQLITE_AUTH 23 /* Authorization denied */ 447#define SQLITE_FORMAT 24 /* Not used */ 448#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 449#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 450#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 451#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 452#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 453#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 454/* end-of-error-codes */ 455 456/* 457** CAPI3REF: Extended Result Codes 458** KEYWORDS: {extended result code definitions} 459** 460** In its default configuration, SQLite API routines return one of 30 integer 461** [result codes]. However, experience has shown that many of 462** these result codes are too coarse-grained. They do not provide as 463** much information about problems as programmers might like. In an effort to 464** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 465** and later) include 466** support for additional result codes that provide more detailed information 467** about errors. These [extended result codes] are enabled or disabled 468** on a per database connection basis using the 469** [sqlite3_extended_result_codes()] API. Or, the extended code for 470** the most recent error can be obtained using 471** [sqlite3_extended_errcode()]. 472*/ 473#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 474#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 475#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 476#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 477#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 478#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 479#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 480#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 481#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 482#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 483#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 484#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 485#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 486#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 487#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 488#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 489#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 490#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 491#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 492#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 493#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 494#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 495#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 496#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 497#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 498#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 499#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 500#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 501#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 502#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 503#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 504#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 505#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 506#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 507#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 508#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 509#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 510#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 511#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 512#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 513#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 514#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 515#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 516#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 517#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 518#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 519#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 520#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 521#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 522#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 523#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 524#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 525#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 526#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 527#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 528#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 529#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 530#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 531#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 532 533/* 534** CAPI3REF: Flags For File Open Operations 535** 536** These bit values are intended for use in the 537** 3rd parameter to the [sqlite3_open_v2()] interface and 538** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 539*/ 540#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 541#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 542#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 543#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 544#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 545#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 546#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 547#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 548#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 549#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 550#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 551#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 552#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 553#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 554#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 555#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 557#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 558#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 559#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 560 561/* Reserved: 0x00F00000 */ 562 563/* 564** CAPI3REF: Device Characteristics 565** 566** The xDeviceCharacteristics method of the [sqlite3_io_methods] 567** object returns an integer which is a vector of these 568** bit values expressing I/O characteristics of the mass storage 569** device that holds the file that the [sqlite3_io_methods] 570** refers to. 571** 572** The SQLITE_IOCAP_ATOMIC property means that all writes of 573** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 574** mean that writes of blocks that are nnn bytes in size and 575** are aligned to an address which is an integer multiple of 576** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 577** that when data is appended to a file, the data is appended 578** first then the size of the file is extended, never the other 579** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 580** information is written to disk in the same order as calls 581** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 582** after reboot following a crash or power loss, the only bytes in a 583** file that were written at the application level might have changed 584** and that adjacent bytes, even bytes within the same sector are 585** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 586** flag indicates that a file cannot be deleted when open. The 587** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 588** read-only media and cannot be changed even by processes with 589** elevated privileges. 590** 591** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 592** filesystem supports doing multiple write operations atomically when those 593** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 594** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 595*/ 596#define SQLITE_IOCAP_ATOMIC 0x00000001 597#define SQLITE_IOCAP_ATOMIC512 0x00000002 598#define SQLITE_IOCAP_ATOMIC1K 0x00000004 599#define SQLITE_IOCAP_ATOMIC2K 0x00000008 600#define SQLITE_IOCAP_ATOMIC4K 0x00000010 601#define SQLITE_IOCAP_ATOMIC8K 0x00000020 602#define SQLITE_IOCAP_ATOMIC16K 0x00000040 603#define SQLITE_IOCAP_ATOMIC32K 0x00000080 604#define SQLITE_IOCAP_ATOMIC64K 0x00000100 605#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 606#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 607#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 608#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 609#define SQLITE_IOCAP_IMMUTABLE 0x00002000 610#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 611 612/* 613** CAPI3REF: File Locking Levels 614** 615** SQLite uses one of these integer values as the second 616** argument to calls it makes to the xLock() and xUnlock() methods 617** of an [sqlite3_io_methods] object. 618*/ 619#define SQLITE_LOCK_NONE 0 620#define SQLITE_LOCK_SHARED 1 621#define SQLITE_LOCK_RESERVED 2 622#define SQLITE_LOCK_PENDING 3 623#define SQLITE_LOCK_EXCLUSIVE 4 624 625/* 626** CAPI3REF: Synchronization Type Flags 627** 628** When SQLite invokes the xSync() method of an 629** [sqlite3_io_methods] object it uses a combination of 630** these integer values as the second argument. 631** 632** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 633** sync operation only needs to flush data to mass storage. Inode 634** information need not be flushed. If the lower four bits of the flag 635** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 636** If the lower four bits equal SQLITE_SYNC_FULL, that means 637** to use Mac OS X style fullsync instead of fsync(). 638** 639** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 640** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 641** settings. The [synchronous pragma] determines when calls to the 642** xSync VFS method occur and applies uniformly across all platforms. 643** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 644** energetic or rigorous or forceful the sync operations are and 645** only make a difference on Mac OSX for the default SQLite code. 646** (Third-party VFS implementations might also make the distinction 647** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 648** operating systems natively supported by SQLite, only Mac OSX 649** cares about the difference.) 650*/ 651#define SQLITE_SYNC_NORMAL 0x00002 652#define SQLITE_SYNC_FULL 0x00003 653#define SQLITE_SYNC_DATAONLY 0x00010 654 655/* 656** CAPI3REF: OS Interface Open File Handle 657** 658** An [sqlite3_file] object represents an open file in the 659** [sqlite3_vfs | OS interface layer]. Individual OS interface 660** implementations will 661** want to subclass this object by appending additional fields 662** for their own use. The pMethods entry is a pointer to an 663** [sqlite3_io_methods] object that defines methods for performing 664** I/O operations on the open file. 665*/ 666typedef struct sqlite3_file sqlite3_file; 667struct sqlite3_file { 668 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 669}; 670 671/* 672** CAPI3REF: OS Interface File Virtual Methods Object 673** 674** Every file opened by the [sqlite3_vfs.xOpen] method populates an 675** [sqlite3_file] object (or, more commonly, a subclass of the 676** [sqlite3_file] object) with a pointer to an instance of this object. 677** This object defines the methods used to perform various operations 678** against the open file represented by the [sqlite3_file] object. 679** 680** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 681** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 682** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 683** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 684** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 685** to NULL. 686** 687** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 688** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 689** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 690** flag may be ORed in to indicate that only the data of the file 691** and not its inode needs to be synced. 692** 693** The integer values to xLock() and xUnlock() are one of 694** <ul> 695** <li> [SQLITE_LOCK_NONE], 696** <li> [SQLITE_LOCK_SHARED], 697** <li> [SQLITE_LOCK_RESERVED], 698** <li> [SQLITE_LOCK_PENDING], or 699** <li> [SQLITE_LOCK_EXCLUSIVE]. 700** </ul> 701** xLock() increases the lock. xUnlock() decreases the lock. 702** The xCheckReservedLock() method checks whether any database connection, 703** either in this process or in some other process, is holding a RESERVED, 704** PENDING, or EXCLUSIVE lock on the file. It returns true 705** if such a lock exists and false otherwise. 706** 707** The xFileControl() method is a generic interface that allows custom 708** VFS implementations to directly control an open file using the 709** [sqlite3_file_control()] interface. The second "op" argument is an 710** integer opcode. The third argument is a generic pointer intended to 711** point to a structure that may contain arguments or space in which to 712** write return values. Potential uses for xFileControl() might be 713** functions to enable blocking locks with timeouts, to change the 714** locking strategy (for example to use dot-file locks), to inquire 715** about the status of a lock, or to break stale locks. The SQLite 716** core reserves all opcodes less than 100 for its own use. 717** A [file control opcodes | list of opcodes] less than 100 is available. 718** Applications that define a custom xFileControl method should use opcodes 719** greater than 100 to avoid conflicts. VFS implementations should 720** return [SQLITE_NOTFOUND] for file control opcodes that they do not 721** recognize. 722** 723** The xSectorSize() method returns the sector size of the 724** device that underlies the file. The sector size is the 725** minimum write that can be performed without disturbing 726** other bytes in the file. The xDeviceCharacteristics() 727** method returns a bit vector describing behaviors of the 728** underlying device: 729** 730** <ul> 731** <li> [SQLITE_IOCAP_ATOMIC] 732** <li> [SQLITE_IOCAP_ATOMIC512] 733** <li> [SQLITE_IOCAP_ATOMIC1K] 734** <li> [SQLITE_IOCAP_ATOMIC2K] 735** <li> [SQLITE_IOCAP_ATOMIC4K] 736** <li> [SQLITE_IOCAP_ATOMIC8K] 737** <li> [SQLITE_IOCAP_ATOMIC16K] 738** <li> [SQLITE_IOCAP_ATOMIC32K] 739** <li> [SQLITE_IOCAP_ATOMIC64K] 740** <li> [SQLITE_IOCAP_SAFE_APPEND] 741** <li> [SQLITE_IOCAP_SEQUENTIAL] 742** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 743** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 744** <li> [SQLITE_IOCAP_IMMUTABLE] 745** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 746** </ul> 747** 748** The SQLITE_IOCAP_ATOMIC property means that all writes of 749** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 750** mean that writes of blocks that are nnn bytes in size and 751** are aligned to an address which is an integer multiple of 752** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 753** that when data is appended to a file, the data is appended 754** first then the size of the file is extended, never the other 755** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 756** information is written to disk in the same order as calls 757** to xWrite(). 758** 759** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 760** in the unread portions of the buffer with zeros. A VFS that 761** fails to zero-fill short reads might seem to work. However, 762** failure to zero-fill short reads will eventually lead to 763** database corruption. 764*/ 765typedef struct sqlite3_io_methods sqlite3_io_methods; 766struct sqlite3_io_methods { 767 int iVersion; 768 int (*xClose)(sqlite3_file*); 769 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 770 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 771 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 772 int (*xSync)(sqlite3_file*, int flags); 773 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 774 int (*xLock)(sqlite3_file*, int); 775 int (*xUnlock)(sqlite3_file*, int); 776 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 777 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 778 int (*xSectorSize)(sqlite3_file*); 779 int (*xDeviceCharacteristics)(sqlite3_file*); 780 /* Methods above are valid for version 1 */ 781 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 782 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 783 void (*xShmBarrier)(sqlite3_file*); 784 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 785 /* Methods above are valid for version 2 */ 786 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 787 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 788 /* Methods above are valid for version 3 */ 789 /* Additional methods may be added in future releases */ 790}; 791 792/* 793** CAPI3REF: Standard File Control Opcodes 794** KEYWORDS: {file control opcodes} {file control opcode} 795** 796** These integer constants are opcodes for the xFileControl method 797** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 798** interface. 799** 800** <ul> 801** <li>[[SQLITE_FCNTL_LOCKSTATE]] 802** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 803** opcode causes the xFileControl method to write the current state of 804** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 805** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 806** into an integer that the pArg argument points to. This capability 807** is used during testing and is only available when the SQLITE_TEST 808** compile-time option is used. 809** 810** <li>[[SQLITE_FCNTL_SIZE_HINT]] 811** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 812** layer a hint of how large the database file will grow to be during the 813** current transaction. This hint is not guaranteed to be accurate but it 814** is often close. The underlying VFS might choose to preallocate database 815** file space based on this hint in order to help writes to the database 816** file run faster. 817** 818** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 819** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 820** extends and truncates the database file in chunks of a size specified 821** by the user. The fourth argument to [sqlite3_file_control()] should 822** point to an integer (type int) containing the new chunk-size to use 823** for the nominated database. Allocating database file space in large 824** chunks (say 1MB at a time), may reduce file-system fragmentation and 825** improve performance on some systems. 826** 827** <li>[[SQLITE_FCNTL_FILE_POINTER]] 828** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 829** to the [sqlite3_file] object associated with a particular database 830** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 831** 832** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 833** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 834** to the [sqlite3_file] object associated with the journal file (either 835** the [rollback journal] or the [write-ahead log]) for a particular database 836** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 837** 838** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 839** No longer in use. 840** 841** <li>[[SQLITE_FCNTL_SYNC]] 842** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 843** sent to the VFS immediately before the xSync method is invoked on a 844** database file descriptor. Or, if the xSync method is not invoked 845** because the user has configured SQLite with 846** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 847** of the xSync method. In most cases, the pointer argument passed with 848** this file-control is NULL. However, if the database file is being synced 849** as part of a multi-database commit, the argument points to a nul-terminated 850** string containing the transactions master-journal file name. VFSes that 851** do not need this signal should silently ignore this opcode. Applications 852** should not call [sqlite3_file_control()] with this opcode as doing so may 853** disrupt the operation of the specialized VFSes that do require it. 854** 855** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 856** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 857** and sent to the VFS after a transaction has been committed immediately 858** but before the database is unlocked. VFSes that do not need this signal 859** should silently ignore this opcode. Applications should not call 860** [sqlite3_file_control()] with this opcode as doing so may disrupt the 861** operation of the specialized VFSes that do require it. 862** 863** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 864** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 865** retry counts and intervals for certain disk I/O operations for the 866** windows [VFS] in order to provide robustness in the presence of 867** anti-virus programs. By default, the windows VFS will retry file read, 868** file write, and file delete operations up to 10 times, with a delay 869** of 25 milliseconds before the first retry and with the delay increasing 870** by an additional 25 milliseconds with each subsequent retry. This 871** opcode allows these two values (10 retries and 25 milliseconds of delay) 872** to be adjusted. The values are changed for all database connections 873** within the same process. The argument is a pointer to an array of two 874** integers where the first integer is the new retry count and the second 875** integer is the delay. If either integer is negative, then the setting 876** is not changed but instead the prior value of that setting is written 877** into the array entry, allowing the current retry settings to be 878** interrogated. The zDbName parameter is ignored. 879** 880** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 881** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 882** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 883** write ahead log and shared memory files used for transaction control 884** are automatically deleted when the latest connection to the database 885** closes. Setting persistent WAL mode causes those files to persist after 886** close. Persisting the files is useful when other processes that do not 887** have write permission on the directory containing the database file want 888** to read the database file, as the WAL and shared memory files must exist 889** in order for the database to be readable. The fourth parameter to 890** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 891** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 892** WAL mode. If the integer is -1, then it is overwritten with the current 893** WAL persistence setting. 894** 895** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 896** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 897** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 898** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 899** xDeviceCharacteristics methods. The fourth parameter to 900** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 901** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 902** mode. If the integer is -1, then it is overwritten with the current 903** zero-damage mode setting. 904** 905** <li>[[SQLITE_FCNTL_OVERWRITE]] 906** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 907** a write transaction to indicate that, unless it is rolled back for some 908** reason, the entire database file will be overwritten by the current 909** transaction. This is used by VACUUM operations. 910** 911** <li>[[SQLITE_FCNTL_VFSNAME]] 912** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 913** all [VFSes] in the VFS stack. The names are of all VFS shims and the 914** final bottom-level VFS are written into memory obtained from 915** [sqlite3_malloc()] and the result is stored in the char* variable 916** that the fourth parameter of [sqlite3_file_control()] points to. 917** The caller is responsible for freeing the memory when done. As with 918** all file-control actions, there is no guarantee that this will actually 919** do anything. Callers should initialize the char* variable to a NULL 920** pointer in case this file-control is not implemented. This file-control 921** is intended for diagnostic use only. 922** 923** <li>[[SQLITE_FCNTL_VFS_POINTER]] 924** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 925** [VFSes] currently in use. ^(The argument X in 926** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 927** of type "[sqlite3_vfs] **". This opcodes will set *X 928** to a pointer to the top-level VFS.)^ 929** ^When there are multiple VFS shims in the stack, this opcode finds the 930** upper-most shim only. 931** 932** <li>[[SQLITE_FCNTL_PRAGMA]] 933** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 934** file control is sent to the open [sqlite3_file] object corresponding 935** to the database file to which the pragma statement refers. ^The argument 936** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 937** pointers to strings (char**) in which the second element of the array 938** is the name of the pragma and the third element is the argument to the 939** pragma or NULL if the pragma has no argument. ^The handler for an 940** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 941** of the char** argument point to a string obtained from [sqlite3_mprintf()] 942** or the equivalent and that string will become the result of the pragma or 943** the error message if the pragma fails. ^If the 944** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 945** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 946** file control returns [SQLITE_OK], then the parser assumes that the 947** VFS has handled the PRAGMA itself and the parser generates a no-op 948** prepared statement if result string is NULL, or that returns a copy 949** of the result string if the string is non-NULL. 950** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 951** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 952** that the VFS encountered an error while handling the [PRAGMA] and the 953** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 954** file control occurs at the beginning of pragma statement analysis and so 955** it is able to override built-in [PRAGMA] statements. 956** 957** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 958** ^The [SQLITE_FCNTL_BUSYHANDLER] 959** file-control may be invoked by SQLite on the database file handle 960** shortly after it is opened in order to provide a custom VFS with access 961** to the connections busy-handler callback. The argument is of type (void **) 962** - an array of two (void *) values. The first (void *) actually points 963** to a function of type (int (*)(void *)). In order to invoke the connections 964** busy-handler, this function should be invoked with the second (void *) in 965** the array as the only argument. If it returns non-zero, then the operation 966** should be retried. If it returns zero, the custom VFS should abandon the 967** current operation. 968** 969** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 970** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 971** to have SQLite generate a 972** temporary filename using the same algorithm that is followed to generate 973** temporary filenames for TEMP tables and other internal uses. The 974** argument should be a char** which will be filled with the filename 975** written into memory obtained from [sqlite3_malloc()]. The caller should 976** invoke [sqlite3_free()] on the result to avoid a memory leak. 977** 978** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 979** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 980** maximum number of bytes that will be used for memory-mapped I/O. 981** The argument is a pointer to a value of type sqlite3_int64 that 982** is an advisory maximum number of bytes in the file to memory map. The 983** pointer is overwritten with the old value. The limit is not changed if 984** the value originally pointed to is negative, and so the current limit 985** can be queried by passing in a pointer to a negative number. This 986** file-control is used internally to implement [PRAGMA mmap_size]. 987** 988** <li>[[SQLITE_FCNTL_TRACE]] 989** The [SQLITE_FCNTL_TRACE] file control provides advisory information 990** to the VFS about what the higher layers of the SQLite stack are doing. 991** This file control is used by some VFS activity tracing [shims]. 992** The argument is a zero-terminated string. Higher layers in the 993** SQLite stack may generate instances of this file control if 994** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 995** 996** <li>[[SQLITE_FCNTL_HAS_MOVED]] 997** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 998** pointer to an integer and it writes a boolean into that integer depending 999** on whether or not the file has been renamed, moved, or deleted since it 1000** was first opened. 1001** 1002** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1003** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1004** underlying native file handle associated with a file handle. This file 1005** control interprets its argument as a pointer to a native file handle and 1006** writes the resulting value there. 1007** 1008** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1009** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1010** opcode causes the xFileControl method to swap the file handle with the one 1011** pointed to by the pArg argument. This capability is used during testing 1012** and only needs to be supported when SQLITE_TEST is defined. 1013** 1014** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1015** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1016** be advantageous to block on the next WAL lock if the lock is not immediately 1017** available. The WAL subsystem issues this signal during rare 1018** circumstances in order to fix a problem with priority inversion. 1019** Applications should <em>not</em> use this file-control. 1020** 1021** <li>[[SQLITE_FCNTL_ZIPVFS]] 1022** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1023** VFS should return SQLITE_NOTFOUND for this opcode. 1024** 1025** <li>[[SQLITE_FCNTL_RBU]] 1026** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1027** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1028** this opcode. 1029** 1030** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1031** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1032** the file descriptor is placed in "batch write mode", which 1033** means all subsequent write operations will be deferred and done 1034** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1035** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1036** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1037** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1038** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1039** no VFS interface calls on the same [sqlite3_file] file descriptor 1040** except for calls to the xWrite method and the xFileControl method 1041** with [SQLITE_FCNTL_SIZE_HINT]. 1042** 1043** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1044** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1045** operations since the previous successful call to 1046** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1047** This file control returns [SQLITE_OK] if and only if the writes were 1048** all performed successfully and have been committed to persistent storage. 1049** ^Regardless of whether or not it is successful, this file control takes 1050** the file descriptor out of batch write mode so that all subsequent 1051** write operations are independent. 1052** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1053** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1054** 1055** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1056** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1057** operations since the previous successful call to 1058** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1059** ^This file control takes the file descriptor out of batch write mode 1060** so that all subsequent write operations are independent. 1061** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1062** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1063** </ul> 1064*/ 1065#define SQLITE_FCNTL_LOCKSTATE 1 1066#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1067#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1068#define SQLITE_FCNTL_LAST_ERRNO 4 1069#define SQLITE_FCNTL_SIZE_HINT 5 1070#define SQLITE_FCNTL_CHUNK_SIZE 6 1071#define SQLITE_FCNTL_FILE_POINTER 7 1072#define SQLITE_FCNTL_SYNC_OMITTED 8 1073#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1074#define SQLITE_FCNTL_PERSIST_WAL 10 1075#define SQLITE_FCNTL_OVERWRITE 11 1076#define SQLITE_FCNTL_VFSNAME 12 1077#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1078#define SQLITE_FCNTL_PRAGMA 14 1079#define SQLITE_FCNTL_BUSYHANDLER 15 1080#define SQLITE_FCNTL_TEMPFILENAME 16 1081#define SQLITE_FCNTL_MMAP_SIZE 18 1082#define SQLITE_FCNTL_TRACE 19 1083#define SQLITE_FCNTL_HAS_MOVED 20 1084#define SQLITE_FCNTL_SYNC 21 1085#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1086#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1087#define SQLITE_FCNTL_WAL_BLOCK 24 1088#define SQLITE_FCNTL_ZIPVFS 25 1089#define SQLITE_FCNTL_RBU 26 1090#define SQLITE_FCNTL_VFS_POINTER 27 1091#define SQLITE_FCNTL_JOURNAL_POINTER 28 1092#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1093#define SQLITE_FCNTL_PDB 30 1094#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1095#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1096#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1097 1098/* deprecated names */ 1099#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1100#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1101#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1102 1103 1104/* 1105** CAPI3REF: Mutex Handle 1106** 1107** The mutex module within SQLite defines [sqlite3_mutex] to be an 1108** abstract type for a mutex object. The SQLite core never looks 1109** at the internal representation of an [sqlite3_mutex]. It only 1110** deals with pointers to the [sqlite3_mutex] object. 1111** 1112** Mutexes are created using [sqlite3_mutex_alloc()]. 1113*/ 1114typedef struct sqlite3_mutex sqlite3_mutex; 1115 1116/* 1117** CAPI3REF: Loadable Extension Thunk 1118** 1119** A pointer to the opaque sqlite3_api_routines structure is passed as 1120** the third parameter to entry points of [loadable extensions]. This 1121** structure must be typedefed in order to work around compiler warnings 1122** on some platforms. 1123*/ 1124typedef struct sqlite3_api_routines sqlite3_api_routines; 1125 1126/* 1127** CAPI3REF: OS Interface Object 1128** 1129** An instance of the sqlite3_vfs object defines the interface between 1130** the SQLite core and the underlying operating system. The "vfs" 1131** in the name of the object stands for "virtual file system". See 1132** the [VFS | VFS documentation] for further information. 1133** 1134** The value of the iVersion field is initially 1 but may be larger in 1135** future versions of SQLite. Additional fields may be appended to this 1136** object when the iVersion value is increased. Note that the structure 1137** of the sqlite3_vfs object changes in the transaction between 1138** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1139** modified. 1140** 1141** The szOsFile field is the size of the subclassed [sqlite3_file] 1142** structure used by this VFS. mxPathname is the maximum length of 1143** a pathname in this VFS. 1144** 1145** Registered sqlite3_vfs objects are kept on a linked list formed by 1146** the pNext pointer. The [sqlite3_vfs_register()] 1147** and [sqlite3_vfs_unregister()] interfaces manage this list 1148** in a thread-safe way. The [sqlite3_vfs_find()] interface 1149** searches the list. Neither the application code nor the VFS 1150** implementation should use the pNext pointer. 1151** 1152** The pNext field is the only field in the sqlite3_vfs 1153** structure that SQLite will ever modify. SQLite will only access 1154** or modify this field while holding a particular static mutex. 1155** The application should never modify anything within the sqlite3_vfs 1156** object once the object has been registered. 1157** 1158** The zName field holds the name of the VFS module. The name must 1159** be unique across all VFS modules. 1160** 1161** [[sqlite3_vfs.xOpen]] 1162** ^SQLite guarantees that the zFilename parameter to xOpen 1163** is either a NULL pointer or string obtained 1164** from xFullPathname() with an optional suffix added. 1165** ^If a suffix is added to the zFilename parameter, it will 1166** consist of a single "-" character followed by no more than 1167** 11 alphanumeric and/or "-" characters. 1168** ^SQLite further guarantees that 1169** the string will be valid and unchanged until xClose() is 1170** called. Because of the previous sentence, 1171** the [sqlite3_file] can safely store a pointer to the 1172** filename if it needs to remember the filename for some reason. 1173** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1174** must invent its own temporary name for the file. ^Whenever the 1175** xFilename parameter is NULL it will also be the case that the 1176** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1177** 1178** The flags argument to xOpen() includes all bits set in 1179** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1180** or [sqlite3_open16()] is used, then flags includes at least 1181** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1182** If xOpen() opens a file read-only then it sets *pOutFlags to 1183** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1184** 1185** ^(SQLite will also add one of the following flags to the xOpen() 1186** call, depending on the object being opened: 1187** 1188** <ul> 1189** <li> [SQLITE_OPEN_MAIN_DB] 1190** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1191** <li> [SQLITE_OPEN_TEMP_DB] 1192** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1193** <li> [SQLITE_OPEN_TRANSIENT_DB] 1194** <li> [SQLITE_OPEN_SUBJOURNAL] 1195** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1196** <li> [SQLITE_OPEN_WAL] 1197** </ul>)^ 1198** 1199** The file I/O implementation can use the object type flags to 1200** change the way it deals with files. For example, an application 1201** that does not care about crash recovery or rollback might make 1202** the open of a journal file a no-op. Writes to this journal would 1203** also be no-ops, and any attempt to read the journal would return 1204** SQLITE_IOERR. Or the implementation might recognize that a database 1205** file will be doing page-aligned sector reads and writes in a random 1206** order and set up its I/O subsystem accordingly. 1207** 1208** SQLite might also add one of the following flags to the xOpen method: 1209** 1210** <ul> 1211** <li> [SQLITE_OPEN_DELETEONCLOSE] 1212** <li> [SQLITE_OPEN_EXCLUSIVE] 1213** </ul> 1214** 1215** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1216** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1217** will be set for TEMP databases and their journals, transient 1218** databases, and subjournals. 1219** 1220** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1221** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1222** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1223** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1224** SQLITE_OPEN_CREATE, is used to indicate that file should always 1225** be created, and that it is an error if it already exists. 1226** It is <i>not</i> used to indicate the file should be opened 1227** for exclusive access. 1228** 1229** ^At least szOsFile bytes of memory are allocated by SQLite 1230** to hold the [sqlite3_file] structure passed as the third 1231** argument to xOpen. The xOpen method does not have to 1232** allocate the structure; it should just fill it in. Note that 1233** the xOpen method must set the sqlite3_file.pMethods to either 1234** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1235** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1236** element will be valid after xOpen returns regardless of the success 1237** or failure of the xOpen call. 1238** 1239** [[sqlite3_vfs.xAccess]] 1240** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1241** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1242** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1243** to test whether a file is at least readable. The file can be a 1244** directory. 1245** 1246** ^SQLite will always allocate at least mxPathname+1 bytes for the 1247** output buffer xFullPathname. The exact size of the output buffer 1248** is also passed as a parameter to both methods. If the output buffer 1249** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1250** handled as a fatal error by SQLite, vfs implementations should endeavor 1251** to prevent this by setting mxPathname to a sufficiently large value. 1252** 1253** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1254** interfaces are not strictly a part of the filesystem, but they are 1255** included in the VFS structure for completeness. 1256** The xRandomness() function attempts to return nBytes bytes 1257** of good-quality randomness into zOut. The return value is 1258** the actual number of bytes of randomness obtained. 1259** The xSleep() method causes the calling thread to sleep for at 1260** least the number of microseconds given. ^The xCurrentTime() 1261** method returns a Julian Day Number for the current date and time as 1262** a floating point value. 1263** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1264** Day Number multiplied by 86400000 (the number of milliseconds in 1265** a 24-hour day). 1266** ^SQLite will use the xCurrentTimeInt64() method to get the current 1267** date and time if that method is available (if iVersion is 2 or 1268** greater and the function pointer is not NULL) and will fall back 1269** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1270** 1271** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1272** are not used by the SQLite core. These optional interfaces are provided 1273** by some VFSes to facilitate testing of the VFS code. By overriding 1274** system calls with functions under its control, a test program can 1275** simulate faults and error conditions that would otherwise be difficult 1276** or impossible to induce. The set of system calls that can be overridden 1277** varies from one VFS to another, and from one version of the same VFS to the 1278** next. Applications that use these interfaces must be prepared for any 1279** or all of these interfaces to be NULL or for their behavior to change 1280** from one release to the next. Applications must not attempt to access 1281** any of these methods if the iVersion of the VFS is less than 3. 1282*/ 1283typedef struct sqlite3_vfs sqlite3_vfs; 1284typedef void (*sqlite3_syscall_ptr)(void); 1285struct sqlite3_vfs { 1286 int iVersion; /* Structure version number (currently 3) */ 1287 int szOsFile; /* Size of subclassed sqlite3_file */ 1288 int mxPathname; /* Maximum file pathname length */ 1289 sqlite3_vfs *pNext; /* Next registered VFS */ 1290 const char *zName; /* Name of this virtual file system */ 1291 void *pAppData; /* Pointer to application-specific data */ 1292 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1293 int flags, int *pOutFlags); 1294 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1295 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1296 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1297 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1298 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1299 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1300 void (*xDlClose)(sqlite3_vfs*, void*); 1301 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1302 int (*xSleep)(sqlite3_vfs*, int microseconds); 1303 int (*xCurrentTime)(sqlite3_vfs*, double*); 1304 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1305 /* 1306 ** The methods above are in version 1 of the sqlite_vfs object 1307 ** definition. Those that follow are added in version 2 or later 1308 */ 1309 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1310 /* 1311 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1312 ** Those below are for version 3 and greater. 1313 */ 1314 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1315 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1316 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1317 /* 1318 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1319 ** New fields may be appended in future versions. The iVersion 1320 ** value will increment whenever this happens. 1321 */ 1322}; 1323 1324/* 1325** CAPI3REF: Flags for the xAccess VFS method 1326** 1327** These integer constants can be used as the third parameter to 1328** the xAccess method of an [sqlite3_vfs] object. They determine 1329** what kind of permissions the xAccess method is looking for. 1330** With SQLITE_ACCESS_EXISTS, the xAccess method 1331** simply checks whether the file exists. 1332** With SQLITE_ACCESS_READWRITE, the xAccess method 1333** checks whether the named directory is both readable and writable 1334** (in other words, if files can be added, removed, and renamed within 1335** the directory). 1336** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1337** [temp_store_directory pragma], though this could change in a future 1338** release of SQLite. 1339** With SQLITE_ACCESS_READ, the xAccess method 1340** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1341** currently unused, though it might be used in a future release of 1342** SQLite. 1343*/ 1344#define SQLITE_ACCESS_EXISTS 0 1345#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1346#define SQLITE_ACCESS_READ 2 /* Unused */ 1347 1348/* 1349** CAPI3REF: Flags for the xShmLock VFS method 1350** 1351** These integer constants define the various locking operations 1352** allowed by the xShmLock method of [sqlite3_io_methods]. The 1353** following are the only legal combinations of flags to the 1354** xShmLock method: 1355** 1356** <ul> 1357** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1358** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1359** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1360** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1361** </ul> 1362** 1363** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1364** was given on the corresponding lock. 1365** 1366** The xShmLock method can transition between unlocked and SHARED or 1367** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1368** and EXCLUSIVE. 1369*/ 1370#define SQLITE_SHM_UNLOCK 1 1371#define SQLITE_SHM_LOCK 2 1372#define SQLITE_SHM_SHARED 4 1373#define SQLITE_SHM_EXCLUSIVE 8 1374 1375/* 1376** CAPI3REF: Maximum xShmLock index 1377** 1378** The xShmLock method on [sqlite3_io_methods] may use values 1379** between 0 and this upper bound as its "offset" argument. 1380** The SQLite core will never attempt to acquire or release a 1381** lock outside of this range 1382*/ 1383#define SQLITE_SHM_NLOCK 8 1384 1385 1386/* 1387** CAPI3REF: Initialize The SQLite Library 1388** 1389** ^The sqlite3_initialize() routine initializes the 1390** SQLite library. ^The sqlite3_shutdown() routine 1391** deallocates any resources that were allocated by sqlite3_initialize(). 1392** These routines are designed to aid in process initialization and 1393** shutdown on embedded systems. Workstation applications using 1394** SQLite normally do not need to invoke either of these routines. 1395** 1396** A call to sqlite3_initialize() is an "effective" call if it is 1397** the first time sqlite3_initialize() is invoked during the lifetime of 1398** the process, or if it is the first time sqlite3_initialize() is invoked 1399** following a call to sqlite3_shutdown(). ^(Only an effective call 1400** of sqlite3_initialize() does any initialization. All other calls 1401** are harmless no-ops.)^ 1402** 1403** A call to sqlite3_shutdown() is an "effective" call if it is the first 1404** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1405** an effective call to sqlite3_shutdown() does any deinitialization. 1406** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1407** 1408** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1409** is not. The sqlite3_shutdown() interface must only be called from a 1410** single thread. All open [database connections] must be closed and all 1411** other SQLite resources must be deallocated prior to invoking 1412** sqlite3_shutdown(). 1413** 1414** Among other things, ^sqlite3_initialize() will invoke 1415** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1416** will invoke sqlite3_os_end(). 1417** 1418** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1419** ^If for some reason, sqlite3_initialize() is unable to initialize 1420** the library (perhaps it is unable to allocate a needed resource such 1421** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1422** 1423** ^The sqlite3_initialize() routine is called internally by many other 1424** SQLite interfaces so that an application usually does not need to 1425** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1426** calls sqlite3_initialize() so the SQLite library will be automatically 1427** initialized when [sqlite3_open()] is called if it has not be initialized 1428** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1429** compile-time option, then the automatic calls to sqlite3_initialize() 1430** are omitted and the application must call sqlite3_initialize() directly 1431** prior to using any other SQLite interface. For maximum portability, 1432** it is recommended that applications always invoke sqlite3_initialize() 1433** directly prior to using any other SQLite interface. Future releases 1434** of SQLite may require this. In other words, the behavior exhibited 1435** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1436** default behavior in some future release of SQLite. 1437** 1438** The sqlite3_os_init() routine does operating-system specific 1439** initialization of the SQLite library. The sqlite3_os_end() 1440** routine undoes the effect of sqlite3_os_init(). Typical tasks 1441** performed by these routines include allocation or deallocation 1442** of static resources, initialization of global variables, 1443** setting up a default [sqlite3_vfs] module, or setting up 1444** a default configuration using [sqlite3_config()]. 1445** 1446** The application should never invoke either sqlite3_os_init() 1447** or sqlite3_os_end() directly. The application should only invoke 1448** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1449** interface is called automatically by sqlite3_initialize() and 1450** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1451** implementations for sqlite3_os_init() and sqlite3_os_end() 1452** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1453** When [custom builds | built for other platforms] 1454** (using the [SQLITE_OS_OTHER=1] compile-time 1455** option) the application must supply a suitable implementation for 1456** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1457** implementation of sqlite3_os_init() or sqlite3_os_end() 1458** must return [SQLITE_OK] on success and some other [error code] upon 1459** failure. 1460*/ 1461int sqlite3_initialize(void); 1462int sqlite3_shutdown(void); 1463int sqlite3_os_init(void); 1464int sqlite3_os_end(void); 1465 1466/* 1467** CAPI3REF: Configuring The SQLite Library 1468** 1469** The sqlite3_config() interface is used to make global configuration 1470** changes to SQLite in order to tune SQLite to the specific needs of 1471** the application. The default configuration is recommended for most 1472** applications and so this routine is usually not necessary. It is 1473** provided to support rare applications with unusual needs. 1474** 1475** <b>The sqlite3_config() interface is not threadsafe. The application 1476** must ensure that no other SQLite interfaces are invoked by other 1477** threads while sqlite3_config() is running.</b> 1478** 1479** The sqlite3_config() interface 1480** may only be invoked prior to library initialization using 1481** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1482** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1483** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1484** Note, however, that ^sqlite3_config() can be called as part of the 1485** implementation of an application-defined [sqlite3_os_init()]. 1486** 1487** The first argument to sqlite3_config() is an integer 1488** [configuration option] that determines 1489** what property of SQLite is to be configured. Subsequent arguments 1490** vary depending on the [configuration option] 1491** in the first argument. 1492** 1493** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1494** ^If the option is unknown or SQLite is unable to set the option 1495** then this routine returns a non-zero [error code]. 1496*/ 1497int sqlite3_config(int, ...); 1498 1499/* 1500** CAPI3REF: Configure database connections 1501** METHOD: sqlite3 1502** 1503** The sqlite3_db_config() interface is used to make configuration 1504** changes to a [database connection]. The interface is similar to 1505** [sqlite3_config()] except that the changes apply to a single 1506** [database connection] (specified in the first argument). 1507** 1508** The second argument to sqlite3_db_config(D,V,...) is the 1509** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1510** that indicates what aspect of the [database connection] is being configured. 1511** Subsequent arguments vary depending on the configuration verb. 1512** 1513** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1514** the call is considered successful. 1515*/ 1516int sqlite3_db_config(sqlite3*, int op, ...); 1517 1518/* 1519** CAPI3REF: Memory Allocation Routines 1520** 1521** An instance of this object defines the interface between SQLite 1522** and low-level memory allocation routines. 1523** 1524** This object is used in only one place in the SQLite interface. 1525** A pointer to an instance of this object is the argument to 1526** [sqlite3_config()] when the configuration option is 1527** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1528** By creating an instance of this object 1529** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1530** during configuration, an application can specify an alternative 1531** memory allocation subsystem for SQLite to use for all of its 1532** dynamic memory needs. 1533** 1534** Note that SQLite comes with several [built-in memory allocators] 1535** that are perfectly adequate for the overwhelming majority of applications 1536** and that this object is only useful to a tiny minority of applications 1537** with specialized memory allocation requirements. This object is 1538** also used during testing of SQLite in order to specify an alternative 1539** memory allocator that simulates memory out-of-memory conditions in 1540** order to verify that SQLite recovers gracefully from such 1541** conditions. 1542** 1543** The xMalloc, xRealloc, and xFree methods must work like the 1544** malloc(), realloc() and free() functions from the standard C library. 1545** ^SQLite guarantees that the second argument to 1546** xRealloc is always a value returned by a prior call to xRoundup. 1547** 1548** xSize should return the allocated size of a memory allocation 1549** previously obtained from xMalloc or xRealloc. The allocated size 1550** is always at least as big as the requested size but may be larger. 1551** 1552** The xRoundup method returns what would be the allocated size of 1553** a memory allocation given a particular requested size. Most memory 1554** allocators round up memory allocations at least to the next multiple 1555** of 8. Some allocators round up to a larger multiple or to a power of 2. 1556** Every memory allocation request coming in through [sqlite3_malloc()] 1557** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1558** that causes the corresponding memory allocation to fail. 1559** 1560** The xInit method initializes the memory allocator. For example, 1561** it might allocate any require mutexes or initialize internal data 1562** structures. The xShutdown method is invoked (indirectly) by 1563** [sqlite3_shutdown()] and should deallocate any resources acquired 1564** by xInit. The pAppData pointer is used as the only parameter to 1565** xInit and xShutdown. 1566** 1567** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1568** the xInit method, so the xInit method need not be threadsafe. The 1569** xShutdown method is only called from [sqlite3_shutdown()] so it does 1570** not need to be threadsafe either. For all other methods, SQLite 1571** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1572** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1573** it is by default) and so the methods are automatically serialized. 1574** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1575** methods must be threadsafe or else make their own arrangements for 1576** serialization. 1577** 1578** SQLite will never invoke xInit() more than once without an intervening 1579** call to xShutdown(). 1580*/ 1581typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1582struct sqlite3_mem_methods { 1583 void *(*xMalloc)(int); /* Memory allocation function */ 1584 void (*xFree)(void*); /* Free a prior allocation */ 1585 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1586 int (*xSize)(void*); /* Return the size of an allocation */ 1587 int (*xRoundup)(int); /* Round up request size to allocation size */ 1588 int (*xInit)(void*); /* Initialize the memory allocator */ 1589 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1590 void *pAppData; /* Argument to xInit() and xShutdown() */ 1591}; 1592 1593/* 1594** CAPI3REF: Configuration Options 1595** KEYWORDS: {configuration option} 1596** 1597** These constants are the available integer configuration options that 1598** can be passed as the first argument to the [sqlite3_config()] interface. 1599** 1600** New configuration options may be added in future releases of SQLite. 1601** Existing configuration options might be discontinued. Applications 1602** should check the return code from [sqlite3_config()] to make sure that 1603** the call worked. The [sqlite3_config()] interface will return a 1604** non-zero [error code] if a discontinued or unsupported configuration option 1605** is invoked. 1606** 1607** <dl> 1608** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1609** <dd>There are no arguments to this option. ^This option sets the 1610** [threading mode] to Single-thread. In other words, it disables 1611** all mutexing and puts SQLite into a mode where it can only be used 1612** by a single thread. ^If SQLite is compiled with 1613** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1614** it is not possible to change the [threading mode] from its default 1615** value of Single-thread and so [sqlite3_config()] will return 1616** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1617** configuration option.</dd> 1618** 1619** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1620** <dd>There are no arguments to this option. ^This option sets the 1621** [threading mode] to Multi-thread. In other words, it disables 1622** mutexing on [database connection] and [prepared statement] objects. 1623** The application is responsible for serializing access to 1624** [database connections] and [prepared statements]. But other mutexes 1625** are enabled so that SQLite will be safe to use in a multi-threaded 1626** environment as long as no two threads attempt to use the same 1627** [database connection] at the same time. ^If SQLite is compiled with 1628** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1629** it is not possible to set the Multi-thread [threading mode] and 1630** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1631** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1632** 1633** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1634** <dd>There are no arguments to this option. ^This option sets the 1635** [threading mode] to Serialized. In other words, this option enables 1636** all mutexes including the recursive 1637** mutexes on [database connection] and [prepared statement] objects. 1638** In this mode (which is the default when SQLite is compiled with 1639** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1640** to [database connections] and [prepared statements] so that the 1641** application is free to use the same [database connection] or the 1642** same [prepared statement] in different threads at the same time. 1643** ^If SQLite is compiled with 1644** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1645** it is not possible to set the Serialized [threading mode] and 1646** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1647** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1648** 1649** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1650** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1651** a pointer to an instance of the [sqlite3_mem_methods] structure. 1652** The argument specifies 1653** alternative low-level memory allocation routines to be used in place of 1654** the memory allocation routines built into SQLite.)^ ^SQLite makes 1655** its own private copy of the content of the [sqlite3_mem_methods] structure 1656** before the [sqlite3_config()] call returns.</dd> 1657** 1658** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1659** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1660** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1661** The [sqlite3_mem_methods] 1662** structure is filled with the currently defined memory allocation routines.)^ 1663** This option can be used to overload the default memory allocation 1664** routines with a wrapper that simulations memory allocation failure or 1665** tracks memory usage, for example. </dd> 1666** 1667** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1668** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1669** type int, interpreted as a boolean, which if true provides a hint to 1670** SQLite that it should avoid large memory allocations if possible. 1671** SQLite will run faster if it is free to make large memory allocations, 1672** but some application might prefer to run slower in exchange for 1673** guarantees about memory fragmentation that are possible if large 1674** allocations are avoided. This hint is normally off. 1675** </dd> 1676** 1677** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1678** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1679** interpreted as a boolean, which enables or disables the collection of 1680** memory allocation statistics. ^(When memory allocation statistics are 1681** disabled, the following SQLite interfaces become non-operational: 1682** <ul> 1683** <li> [sqlite3_memory_used()] 1684** <li> [sqlite3_memory_highwater()] 1685** <li> [sqlite3_soft_heap_limit64()] 1686** <li> [sqlite3_status64()] 1687** </ul>)^ 1688** ^Memory allocation statistics are enabled by default unless SQLite is 1689** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1690** allocation statistics are disabled by default. 1691** </dd> 1692** 1693** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1694** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1695** </dd> 1696** 1697** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1698** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1699** that SQLite can use for the database page cache with the default page 1700** cache implementation. 1701** This configuration option is a no-op if an application-define page 1702** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1703** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1704** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1705** and the number of cache lines (N). 1706** The sz argument should be the size of the largest database page 1707** (a power of two between 512 and 65536) plus some extra bytes for each 1708** page header. ^The number of extra bytes needed by the page header 1709** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1710** ^It is harmless, apart from the wasted memory, 1711** for the sz parameter to be larger than necessary. The pMem 1712** argument must be either a NULL pointer or a pointer to an 8-byte 1713** aligned block of memory of at least sz*N bytes, otherwise 1714** subsequent behavior is undefined. 1715** ^When pMem is not NULL, SQLite will strive to use the memory provided 1716** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1717** a page cache line is larger than sz bytes or if all of the pMem buffer 1718** is exhausted. 1719** ^If pMem is NULL and N is non-zero, then each database connection 1720** does an initial bulk allocation for page cache memory 1721** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1722** of -1024*N bytes if N is negative, . ^If additional 1723** page cache memory is needed beyond what is provided by the initial 1724** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1725** additional cache line. </dd> 1726** 1727** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1728** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1729** that SQLite will use for all of its dynamic memory allocation needs 1730** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1731** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1732** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1733** [SQLITE_ERROR] if invoked otherwise. 1734** ^There are three arguments to SQLITE_CONFIG_HEAP: 1735** An 8-byte aligned pointer to the memory, 1736** the number of bytes in the memory buffer, and the minimum allocation size. 1737** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1738** to using its default memory allocator (the system malloc() implementation), 1739** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1740** memory pointer is not NULL then the alternative memory 1741** allocator is engaged to handle all of SQLites memory allocation needs. 1742** The first pointer (the memory pointer) must be aligned to an 8-byte 1743** boundary or subsequent behavior of SQLite will be undefined. 1744** The minimum allocation size is capped at 2**12. Reasonable values 1745** for the minimum allocation size are 2**5 through 2**8.</dd> 1746** 1747** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1748** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1749** pointer to an instance of the [sqlite3_mutex_methods] structure. 1750** The argument specifies alternative low-level mutex routines to be used 1751** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1752** the content of the [sqlite3_mutex_methods] structure before the call to 1753** [sqlite3_config()] returns. ^If SQLite is compiled with 1754** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1755** the entire mutexing subsystem is omitted from the build and hence calls to 1756** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1757** return [SQLITE_ERROR].</dd> 1758** 1759** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1760** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1761** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1762** [sqlite3_mutex_methods] 1763** structure is filled with the currently defined mutex routines.)^ 1764** This option can be used to overload the default mutex allocation 1765** routines with a wrapper used to track mutex usage for performance 1766** profiling or testing, for example. ^If SQLite is compiled with 1767** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1768** the entire mutexing subsystem is omitted from the build and hence calls to 1769** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1770** return [SQLITE_ERROR].</dd> 1771** 1772** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1773** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1774** the default size of lookaside memory on each [database connection]. 1775** The first argument is the 1776** size of each lookaside buffer slot and the second is the number of 1777** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1778** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1779** option to [sqlite3_db_config()] can be used to change the lookaside 1780** configuration on individual connections.)^ </dd> 1781** 1782** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1783** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1784** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1785** the interface to a custom page cache implementation.)^ 1786** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1787** 1788** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1789** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1790** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1791** the current page cache implementation into that object.)^ </dd> 1792** 1793** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1794** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1795** global [error log]. 1796** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1797** function with a call signature of void(*)(void*,int,const char*), 1798** and a pointer to void. ^If the function pointer is not NULL, it is 1799** invoked by [sqlite3_log()] to process each logging event. ^If the 1800** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1801** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1802** passed through as the first parameter to the application-defined logger 1803** function whenever that function is invoked. ^The second parameter to 1804** the logger function is a copy of the first parameter to the corresponding 1805** [sqlite3_log()] call and is intended to be a [result code] or an 1806** [extended result code]. ^The third parameter passed to the logger is 1807** log message after formatting via [sqlite3_snprintf()]. 1808** The SQLite logging interface is not reentrant; the logger function 1809** supplied by the application must not invoke any SQLite interface. 1810** In a multi-threaded application, the application-defined logger 1811** function must be threadsafe. </dd> 1812** 1813** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1814** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1815** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1816** then URI handling is globally disabled.)^ ^If URI handling is globally 1817** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1818** [sqlite3_open16()] or 1819** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1820** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1821** connection is opened. ^If it is globally disabled, filenames are 1822** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1823** database connection is opened. ^(By default, URI handling is globally 1824** disabled. The default value may be changed by compiling with the 1825** [SQLITE_USE_URI] symbol defined.)^ 1826** 1827** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1828** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1829** argument which is interpreted as a boolean in order to enable or disable 1830** the use of covering indices for full table scans in the query optimizer. 1831** ^The default setting is determined 1832** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1833** if that compile-time option is omitted. 1834** The ability to disable the use of covering indices for full table scans 1835** is because some incorrectly coded legacy applications might malfunction 1836** when the optimization is enabled. Providing the ability to 1837** disable the optimization allows the older, buggy application code to work 1838** without change even with newer versions of SQLite. 1839** 1840** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1841** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1842** <dd> These options are obsolete and should not be used by new code. 1843** They are retained for backwards compatibility but are now no-ops. 1844** </dd> 1845** 1846** [[SQLITE_CONFIG_SQLLOG]] 1847** <dt>SQLITE_CONFIG_SQLLOG 1848** <dd>This option is only available if sqlite is compiled with the 1849** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1850** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1851** The second should be of type (void*). The callback is invoked by the library 1852** in three separate circumstances, identified by the value passed as the 1853** fourth parameter. If the fourth parameter is 0, then the database connection 1854** passed as the second argument has just been opened. The third argument 1855** points to a buffer containing the name of the main database file. If the 1856** fourth parameter is 1, then the SQL statement that the third parameter 1857** points to has just been executed. Or, if the fourth parameter is 2, then 1858** the connection being passed as the second parameter is being closed. The 1859** third parameter is passed NULL In this case. An example of using this 1860** configuration option can be seen in the "test_sqllog.c" source file in 1861** the canonical SQLite source tree.</dd> 1862** 1863** [[SQLITE_CONFIG_MMAP_SIZE]] 1864** <dt>SQLITE_CONFIG_MMAP_SIZE 1865** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1866** that are the default mmap size limit (the default setting for 1867** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1868** ^The default setting can be overridden by each database connection using 1869** either the [PRAGMA mmap_size] command, or by using the 1870** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1871** will be silently truncated if necessary so that it does not exceed the 1872** compile-time maximum mmap size set by the 1873** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1874** ^If either argument to this option is negative, then that argument is 1875** changed to its compile-time default. 1876** 1877** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1878** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1879** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1880** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1881** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1882** that specifies the maximum size of the created heap. 1883** 1884** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1885** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1886** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1887** is a pointer to an integer and writes into that integer the number of extra 1888** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1889** The amount of extra space required can change depending on the compiler, 1890** target platform, and SQLite version. 1891** 1892** [[SQLITE_CONFIG_PMASZ]] 1893** <dt>SQLITE_CONFIG_PMASZ 1894** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1895** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1896** sorter to that integer. The default minimum PMA Size is set by the 1897** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1898** to help with sort operations when multithreaded sorting 1899** is enabled (using the [PRAGMA threads] command) and the amount of content 1900** to be sorted exceeds the page size times the minimum of the 1901** [PRAGMA cache_size] setting and this value. 1902** 1903** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1904** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1905** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1906** becomes the [statement journal] spill-to-disk threshold. 1907** [Statement journals] are held in memory until their size (in bytes) 1908** exceeds this threshold, at which point they are written to disk. 1909** Or if the threshold is -1, statement journals are always held 1910** exclusively in memory. 1911** Since many statement journals never become large, setting the spill 1912** threshold to a value such as 64KiB can greatly reduce the amount of 1913** I/O required to support statement rollback. 1914** The default value for this setting is controlled by the 1915** [SQLITE_STMTJRNL_SPILL] compile-time option. 1916** </dl> 1917*/ 1918#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1919#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1920#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1921#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1922#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1923#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1924#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1925#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1926#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1927#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1928#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1929/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1930#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1931#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1932#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1933#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1934#define SQLITE_CONFIG_URI 17 /* int */ 1935#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1936#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1937#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1938#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1939#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1940#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1941#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1942#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1943#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1944#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1945 1946/* 1947** CAPI3REF: Database Connection Configuration Options 1948** 1949** These constants are the available integer configuration options that 1950** can be passed as the second argument to the [sqlite3_db_config()] interface. 1951** 1952** New configuration options may be added in future releases of SQLite. 1953** Existing configuration options might be discontinued. Applications 1954** should check the return code from [sqlite3_db_config()] to make sure that 1955** the call worked. ^The [sqlite3_db_config()] interface will return a 1956** non-zero [error code] if a discontinued or unsupported configuration option 1957** is invoked. 1958** 1959** <dl> 1960** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1961** <dd> ^This option takes three additional arguments that determine the 1962** [lookaside memory allocator] configuration for the [database connection]. 1963** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1964** pointer to a memory buffer to use for lookaside memory. 1965** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1966** may be NULL in which case SQLite will allocate the 1967** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1968** size of each lookaside buffer slot. ^The third argument is the number of 1969** slots. The size of the buffer in the first argument must be greater than 1970** or equal to the product of the second and third arguments. The buffer 1971** must be aligned to an 8-byte boundary. ^If the second argument to 1972** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1973** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1974** configuration for a database connection can only be changed when that 1975** connection is not currently using lookaside memory, or in other words 1976** when the "current value" returned by 1977** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1978** Any attempt to change the lookaside memory configuration when lookaside 1979** memory is in use leaves the configuration unchanged and returns 1980** [SQLITE_BUSY].)^</dd> 1981** 1982** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1983** <dd> ^This option is used to enable or disable the enforcement of 1984** [foreign key constraints]. There should be two additional arguments. 1985** The first argument is an integer which is 0 to disable FK enforcement, 1986** positive to enable FK enforcement or negative to leave FK enforcement 1987** unchanged. The second parameter is a pointer to an integer into which 1988** is written 0 or 1 to indicate whether FK enforcement is off or on 1989** following this call. The second parameter may be a NULL pointer, in 1990** which case the FK enforcement setting is not reported back. </dd> 1991** 1992** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1993** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1994** There should be two additional arguments. 1995** The first argument is an integer which is 0 to disable triggers, 1996** positive to enable triggers or negative to leave the setting unchanged. 1997** The second parameter is a pointer to an integer into which 1998** is written 0 or 1 to indicate whether triggers are disabled or enabled 1999** following this call. The second parameter may be a NULL pointer, in 2000** which case the trigger setting is not reported back. </dd> 2001** 2002** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2003** <dd> ^This option is used to enable or disable the two-argument 2004** version of the [fts3_tokenizer()] function which is part of the 2005** [FTS3] full-text search engine extension. 2006** There should be two additional arguments. 2007** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2008** positive to enable fts3_tokenizer() or negative to leave the setting 2009** unchanged. 2010** The second parameter is a pointer to an integer into which 2011** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2012** following this call. The second parameter may be a NULL pointer, in 2013** which case the new setting is not reported back. </dd> 2014** 2015** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2016** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2017** interface independently of the [load_extension()] SQL function. 2018** The [sqlite3_enable_load_extension()] API enables or disables both the 2019** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2020** There should be two additional arguments. 2021** When the first argument to this interface is 1, then only the C-API is 2022** enabled and the SQL function remains disabled. If the first argument to 2023** this interface is 0, then both the C-API and the SQL function are disabled. 2024** If the first argument is -1, then no changes are made to state of either the 2025** C-API or the SQL function. 2026** The second parameter is a pointer to an integer into which 2027** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2028** is disabled or enabled following this call. The second parameter may 2029** be a NULL pointer, in which case the new setting is not reported back. 2030** </dd> 2031** 2032** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2033** <dd> ^This option is used to change the name of the "main" database 2034** schema. ^The sole argument is a pointer to a constant UTF8 string 2035** which will become the new schema name in place of "main". ^SQLite 2036** does not make a copy of the new main schema name string, so the application 2037** must ensure that the argument passed into this DBCONFIG option is unchanged 2038** until after the database connection closes. 2039** </dd> 2040** 2041** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2042** <dd> Usually, when a database in wal mode is closed or detached from a 2043** database handle, SQLite checks if this will mean that there are now no 2044** connections at all to the database. If so, it performs a checkpoint 2045** operation before closing the connection. This option may be used to 2046** override this behaviour. The first parameter passed to this operation 2047** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2048** default) to enable them. The second parameter is a pointer to an integer 2049** into which is written 0 or 1 to indicate whether checkpoints-on-close 2050** have been disabled - 0 if they are not disabled, 1 if they are. 2051** </dd> 2052** 2053** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2054** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2055** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2056** a single SQL query statement will always use the same algorithm regardless 2057** of values of [bound parameters].)^ The QPSG disables some query optimizations 2058** that look at the values of bound parameters, which can make some queries 2059** slower. But the QPSG has the advantage of more predictable behavior. With 2060** the QPSG active, SQLite will always use the same query plan in the field as 2061** was used during testing in the lab. 2062** </dd> 2063** 2064** </dl> 2065*/ 2066#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2067#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2068#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2069#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2070#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2071#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2072#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2073#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2074 2075 2076/* 2077** CAPI3REF: Enable Or Disable Extended Result Codes 2078** METHOD: sqlite3 2079** 2080** ^The sqlite3_extended_result_codes() routine enables or disables the 2081** [extended result codes] feature of SQLite. ^The extended result 2082** codes are disabled by default for historical compatibility. 2083*/ 2084int sqlite3_extended_result_codes(sqlite3*, int onoff); 2085 2086/* 2087** CAPI3REF: Last Insert Rowid 2088** METHOD: sqlite3 2089** 2090** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2091** has a unique 64-bit signed 2092** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2093** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2094** names are not also used by explicitly declared columns. ^If 2095** the table has a column of type [INTEGER PRIMARY KEY] then that column 2096** is another alias for the rowid. 2097** 2098** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2099** the most recent successful [INSERT] into a rowid table or [virtual table] 2100** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2101** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2102** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2103** zero. 2104** 2105** As well as being set automatically as rows are inserted into database 2106** tables, the value returned by this function may be set explicitly by 2107** [sqlite3_set_last_insert_rowid()] 2108** 2109** Some virtual table implementations may INSERT rows into rowid tables as 2110** part of committing a transaction (e.g. to flush data accumulated in memory 2111** to disk). In this case subsequent calls to this function return the rowid 2112** associated with these internal INSERT operations, which leads to 2113** unintuitive results. Virtual table implementations that do write to rowid 2114** tables in this way can avoid this problem by restoring the original 2115** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2116** control to the user. 2117** 2118** ^(If an [INSERT] occurs within a trigger then this routine will 2119** return the [rowid] of the inserted row as long as the trigger is 2120** running. Once the trigger program ends, the value returned 2121** by this routine reverts to what it was before the trigger was fired.)^ 2122** 2123** ^An [INSERT] that fails due to a constraint violation is not a 2124** successful [INSERT] and does not change the value returned by this 2125** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2126** and INSERT OR ABORT make no changes to the return value of this 2127** routine when their insertion fails. ^(When INSERT OR REPLACE 2128** encounters a constraint violation, it does not fail. The 2129** INSERT continues to completion after deleting rows that caused 2130** the constraint problem so INSERT OR REPLACE will always change 2131** the return value of this interface.)^ 2132** 2133** ^For the purposes of this routine, an [INSERT] is considered to 2134** be successful even if it is subsequently rolled back. 2135** 2136** This function is accessible to SQL statements via the 2137** [last_insert_rowid() SQL function]. 2138** 2139** If a separate thread performs a new [INSERT] on the same 2140** database connection while the [sqlite3_last_insert_rowid()] 2141** function is running and thus changes the last insert [rowid], 2142** then the value returned by [sqlite3_last_insert_rowid()] is 2143** unpredictable and might not equal either the old or the new 2144** last insert [rowid]. 2145*/ 2146sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2147 2148/* 2149** CAPI3REF: Set the Last Insert Rowid value. 2150** METHOD: sqlite3 2151** 2152** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2153** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2154** without inserting a row into the database. 2155*/ 2156void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2157 2158/* 2159** CAPI3REF: Count The Number Of Rows Modified 2160** METHOD: sqlite3 2161** 2162** ^This function returns the number of rows modified, inserted or 2163** deleted by the most recently completed INSERT, UPDATE or DELETE 2164** statement on the database connection specified by the only parameter. 2165** ^Executing any other type of SQL statement does not modify the value 2166** returned by this function. 2167** 2168** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2169** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2170** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2171** 2172** Changes to a view that are intercepted by 2173** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2174** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2175** DELETE statement run on a view is always zero. Only changes made to real 2176** tables are counted. 2177** 2178** Things are more complicated if the sqlite3_changes() function is 2179** executed while a trigger program is running. This may happen if the 2180** program uses the [changes() SQL function], or if some other callback 2181** function invokes sqlite3_changes() directly. Essentially: 2182** 2183** <ul> 2184** <li> ^(Before entering a trigger program the value returned by 2185** sqlite3_changes() function is saved. After the trigger program 2186** has finished, the original value is restored.)^ 2187** 2188** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2189** statement sets the value returned by sqlite3_changes() 2190** upon completion as normal. Of course, this value will not include 2191** any changes performed by sub-triggers, as the sqlite3_changes() 2192** value will be saved and restored after each sub-trigger has run.)^ 2193** </ul> 2194** 2195** ^This means that if the changes() SQL function (or similar) is used 2196** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2197** returns the value as set when the calling statement began executing. 2198** ^If it is used by the second or subsequent such statement within a trigger 2199** program, the value returned reflects the number of rows modified by the 2200** previous INSERT, UPDATE or DELETE statement within the same trigger. 2201** 2202** See also the [sqlite3_total_changes()] interface, the 2203** [count_changes pragma], and the [changes() SQL function]. 2204** 2205** If a separate thread makes changes on the same database connection 2206** while [sqlite3_changes()] is running then the value returned 2207** is unpredictable and not meaningful. 2208*/ 2209int sqlite3_changes(sqlite3*); 2210 2211/* 2212** CAPI3REF: Total Number Of Rows Modified 2213** METHOD: sqlite3 2214** 2215** ^This function returns the total number of rows inserted, modified or 2216** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2217** since the database connection was opened, including those executed as 2218** part of trigger programs. ^Executing any other type of SQL statement 2219** does not affect the value returned by sqlite3_total_changes(). 2220** 2221** ^Changes made as part of [foreign key actions] are included in the 2222** count, but those made as part of REPLACE constraint resolution are 2223** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2224** are not counted. 2225** 2226** See also the [sqlite3_changes()] interface, the 2227** [count_changes pragma], and the [total_changes() SQL function]. 2228** 2229** If a separate thread makes changes on the same database connection 2230** while [sqlite3_total_changes()] is running then the value 2231** returned is unpredictable and not meaningful. 2232*/ 2233int sqlite3_total_changes(sqlite3*); 2234 2235/* 2236** CAPI3REF: Interrupt A Long-Running Query 2237** METHOD: sqlite3 2238** 2239** ^This function causes any pending database operation to abort and 2240** return at its earliest opportunity. This routine is typically 2241** called in response to a user action such as pressing "Cancel" 2242** or Ctrl-C where the user wants a long query operation to halt 2243** immediately. 2244** 2245** ^It is safe to call this routine from a thread different from the 2246** thread that is currently running the database operation. But it 2247** is not safe to call this routine with a [database connection] that 2248** is closed or might close before sqlite3_interrupt() returns. 2249** 2250** ^If an SQL operation is very nearly finished at the time when 2251** sqlite3_interrupt() is called, then it might not have an opportunity 2252** to be interrupted and might continue to completion. 2253** 2254** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2255** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2256** that is inside an explicit transaction, then the entire transaction 2257** will be rolled back automatically. 2258** 2259** ^The sqlite3_interrupt(D) call is in effect until all currently running 2260** SQL statements on [database connection] D complete. ^Any new SQL statements 2261** that are started after the sqlite3_interrupt() call and before the 2262** running statements reaches zero are interrupted as if they had been 2263** running prior to the sqlite3_interrupt() call. ^New SQL statements 2264** that are started after the running statement count reaches zero are 2265** not effected by the sqlite3_interrupt(). 2266** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2267** SQL statements is a no-op and has no effect on SQL statements 2268** that are started after the sqlite3_interrupt() call returns. 2269*/ 2270void sqlite3_interrupt(sqlite3*); 2271 2272/* 2273** CAPI3REF: Determine If An SQL Statement Is Complete 2274** 2275** These routines are useful during command-line input to determine if the 2276** currently entered text seems to form a complete SQL statement or 2277** if additional input is needed before sending the text into 2278** SQLite for parsing. ^These routines return 1 if the input string 2279** appears to be a complete SQL statement. ^A statement is judged to be 2280** complete if it ends with a semicolon token and is not a prefix of a 2281** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2282** string literals or quoted identifier names or comments are not 2283** independent tokens (they are part of the token in which they are 2284** embedded) and thus do not count as a statement terminator. ^Whitespace 2285** and comments that follow the final semicolon are ignored. 2286** 2287** ^These routines return 0 if the statement is incomplete. ^If a 2288** memory allocation fails, then SQLITE_NOMEM is returned. 2289** 2290** ^These routines do not parse the SQL statements thus 2291** will not detect syntactically incorrect SQL. 2292** 2293** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2294** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2295** automatically by sqlite3_complete16(). If that initialization fails, 2296** then the return value from sqlite3_complete16() will be non-zero 2297** regardless of whether or not the input SQL is complete.)^ 2298** 2299** The input to [sqlite3_complete()] must be a zero-terminated 2300** UTF-8 string. 2301** 2302** The input to [sqlite3_complete16()] must be a zero-terminated 2303** UTF-16 string in native byte order. 2304*/ 2305int sqlite3_complete(const char *sql); 2306int sqlite3_complete16(const void *sql); 2307 2308/* 2309** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2310** KEYWORDS: {busy-handler callback} {busy handler} 2311** METHOD: sqlite3 2312** 2313** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2314** that might be invoked with argument P whenever 2315** an attempt is made to access a database table associated with 2316** [database connection] D when another thread 2317** or process has the table locked. 2318** The sqlite3_busy_handler() interface is used to implement 2319** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2320** 2321** ^If the busy callback is NULL, then [SQLITE_BUSY] 2322** is returned immediately upon encountering the lock. ^If the busy callback 2323** is not NULL, then the callback might be invoked with two arguments. 2324** 2325** ^The first argument to the busy handler is a copy of the void* pointer which 2326** is the third argument to sqlite3_busy_handler(). ^The second argument to 2327** the busy handler callback is the number of times that the busy handler has 2328** been invoked previously for the same locking event. ^If the 2329** busy callback returns 0, then no additional attempts are made to 2330** access the database and [SQLITE_BUSY] is returned 2331** to the application. 2332** ^If the callback returns non-zero, then another attempt 2333** is made to access the database and the cycle repeats. 2334** 2335** The presence of a busy handler does not guarantee that it will be invoked 2336** when there is lock contention. ^If SQLite determines that invoking the busy 2337** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2338** to the application instead of invoking the 2339** busy handler. 2340** Consider a scenario where one process is holding a read lock that 2341** it is trying to promote to a reserved lock and 2342** a second process is holding a reserved lock that it is trying 2343** to promote to an exclusive lock. The first process cannot proceed 2344** because it is blocked by the second and the second process cannot 2345** proceed because it is blocked by the first. If both processes 2346** invoke the busy handlers, neither will make any progress. Therefore, 2347** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2348** will induce the first process to release its read lock and allow 2349** the second process to proceed. 2350** 2351** ^The default busy callback is NULL. 2352** 2353** ^(There can only be a single busy handler defined for each 2354** [database connection]. Setting a new busy handler clears any 2355** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2356** or evaluating [PRAGMA busy_timeout=N] will change the 2357** busy handler and thus clear any previously set busy handler. 2358** 2359** The busy callback should not take any actions which modify the 2360** database connection that invoked the busy handler. In other words, 2361** the busy handler is not reentrant. Any such actions 2362** result in undefined behavior. 2363** 2364** A busy handler must not close the database connection 2365** or [prepared statement] that invoked the busy handler. 2366*/ 2367int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2368 2369/* 2370** CAPI3REF: Set A Busy Timeout 2371** METHOD: sqlite3 2372** 2373** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2374** for a specified amount of time when a table is locked. ^The handler 2375** will sleep multiple times until at least "ms" milliseconds of sleeping 2376** have accumulated. ^After at least "ms" milliseconds of sleeping, 2377** the handler returns 0 which causes [sqlite3_step()] to return 2378** [SQLITE_BUSY]. 2379** 2380** ^Calling this routine with an argument less than or equal to zero 2381** turns off all busy handlers. 2382** 2383** ^(There can only be a single busy handler for a particular 2384** [database connection] at any given moment. If another busy handler 2385** was defined (using [sqlite3_busy_handler()]) prior to calling 2386** this routine, that other busy handler is cleared.)^ 2387** 2388** See also: [PRAGMA busy_timeout] 2389*/ 2390int sqlite3_busy_timeout(sqlite3*, int ms); 2391 2392/* 2393** CAPI3REF: Convenience Routines For Running Queries 2394** METHOD: sqlite3 2395** 2396** This is a legacy interface that is preserved for backwards compatibility. 2397** Use of this interface is not recommended. 2398** 2399** Definition: A <b>result table</b> is memory data structure created by the 2400** [sqlite3_get_table()] interface. A result table records the 2401** complete query results from one or more queries. 2402** 2403** The table conceptually has a number of rows and columns. But 2404** these numbers are not part of the result table itself. These 2405** numbers are obtained separately. Let N be the number of rows 2406** and M be the number of columns. 2407** 2408** A result table is an array of pointers to zero-terminated UTF-8 strings. 2409** There are (N+1)*M elements in the array. The first M pointers point 2410** to zero-terminated strings that contain the names of the columns. 2411** The remaining entries all point to query results. NULL values result 2412** in NULL pointers. All other values are in their UTF-8 zero-terminated 2413** string representation as returned by [sqlite3_column_text()]. 2414** 2415** A result table might consist of one or more memory allocations. 2416** It is not safe to pass a result table directly to [sqlite3_free()]. 2417** A result table should be deallocated using [sqlite3_free_table()]. 2418** 2419** ^(As an example of the result table format, suppose a query result 2420** is as follows: 2421** 2422** <blockquote><pre> 2423** Name | Age 2424** ----------------------- 2425** Alice | 43 2426** Bob | 28 2427** Cindy | 21 2428** </pre></blockquote> 2429** 2430** There are two column (M==2) and three rows (N==3). Thus the 2431** result table has 8 entries. Suppose the result table is stored 2432** in an array names azResult. Then azResult holds this content: 2433** 2434** <blockquote><pre> 2435** azResult[0] = "Name"; 2436** azResult[1] = "Age"; 2437** azResult[2] = "Alice"; 2438** azResult[3] = "43"; 2439** azResult[4] = "Bob"; 2440** azResult[5] = "28"; 2441** azResult[6] = "Cindy"; 2442** azResult[7] = "21"; 2443** </pre></blockquote>)^ 2444** 2445** ^The sqlite3_get_table() function evaluates one or more 2446** semicolon-separated SQL statements in the zero-terminated UTF-8 2447** string of its 2nd parameter and returns a result table to the 2448** pointer given in its 3rd parameter. 2449** 2450** After the application has finished with the result from sqlite3_get_table(), 2451** it must pass the result table pointer to sqlite3_free_table() in order to 2452** release the memory that was malloced. Because of the way the 2453** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2454** function must not try to call [sqlite3_free()] directly. Only 2455** [sqlite3_free_table()] is able to release the memory properly and safely. 2456** 2457** The sqlite3_get_table() interface is implemented as a wrapper around 2458** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2459** to any internal data structures of SQLite. It uses only the public 2460** interface defined here. As a consequence, errors that occur in the 2461** wrapper layer outside of the internal [sqlite3_exec()] call are not 2462** reflected in subsequent calls to [sqlite3_errcode()] or 2463** [sqlite3_errmsg()]. 2464*/ 2465int sqlite3_get_table( 2466 sqlite3 *db, /* An open database */ 2467 const char *zSql, /* SQL to be evaluated */ 2468 char ***pazResult, /* Results of the query */ 2469 int *pnRow, /* Number of result rows written here */ 2470 int *pnColumn, /* Number of result columns written here */ 2471 char **pzErrmsg /* Error msg written here */ 2472); 2473void sqlite3_free_table(char **result); 2474 2475/* 2476** CAPI3REF: Formatted String Printing Functions 2477** 2478** These routines are work-alikes of the "printf()" family of functions 2479** from the standard C library. 2480** These routines understand most of the common K&R formatting options, 2481** plus some additional non-standard formats, detailed below. 2482** Note that some of the more obscure formatting options from recent 2483** C-library standards are omitted from this implementation. 2484** 2485** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2486** results into memory obtained from [sqlite3_malloc()]. 2487** The strings returned by these two routines should be 2488** released by [sqlite3_free()]. ^Both routines return a 2489** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2490** memory to hold the resulting string. 2491** 2492** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2493** the standard C library. The result is written into the 2494** buffer supplied as the second parameter whose size is given by 2495** the first parameter. Note that the order of the 2496** first two parameters is reversed from snprintf().)^ This is an 2497** historical accident that cannot be fixed without breaking 2498** backwards compatibility. ^(Note also that sqlite3_snprintf() 2499** returns a pointer to its buffer instead of the number of 2500** characters actually written into the buffer.)^ We admit that 2501** the number of characters written would be a more useful return 2502** value but we cannot change the implementation of sqlite3_snprintf() 2503** now without breaking compatibility. 2504** 2505** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2506** guarantees that the buffer is always zero-terminated. ^The first 2507** parameter "n" is the total size of the buffer, including space for 2508** the zero terminator. So the longest string that can be completely 2509** written will be n-1 characters. 2510** 2511** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2512** 2513** These routines all implement some additional formatting 2514** options that are useful for constructing SQL statements. 2515** All of the usual printf() formatting options apply. In addition, there 2516** is are "%q", "%Q", "%w" and "%z" options. 2517** 2518** ^(The %q option works like %s in that it substitutes a nul-terminated 2519** string from the argument list. But %q also doubles every '\'' character. 2520** %q is designed for use inside a string literal.)^ By doubling each '\'' 2521** character it escapes that character and allows it to be inserted into 2522** the string. 2523** 2524** For example, assume the string variable zText contains text as follows: 2525** 2526** <blockquote><pre> 2527** char *zText = "It's a happy day!"; 2528** </pre></blockquote> 2529** 2530** One can use this text in an SQL statement as follows: 2531** 2532** <blockquote><pre> 2533** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2534** sqlite3_exec(db, zSQL, 0, 0, 0); 2535** sqlite3_free(zSQL); 2536** </pre></blockquote> 2537** 2538** Because the %q format string is used, the '\'' character in zText 2539** is escaped and the SQL generated is as follows: 2540** 2541** <blockquote><pre> 2542** INSERT INTO table1 VALUES('It''s a happy day!') 2543** </pre></blockquote> 2544** 2545** This is correct. Had we used %s instead of %q, the generated SQL 2546** would have looked like this: 2547** 2548** <blockquote><pre> 2549** INSERT INTO table1 VALUES('It's a happy day!'); 2550** </pre></blockquote> 2551** 2552** This second example is an SQL syntax error. As a general rule you should 2553** always use %q instead of %s when inserting text into a string literal. 2554** 2555** ^(The %Q option works like %q except it also adds single quotes around 2556** the outside of the total string. Additionally, if the parameter in the 2557** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2558** single quotes).)^ So, for example, one could say: 2559** 2560** <blockquote><pre> 2561** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2562** sqlite3_exec(db, zSQL, 0, 0, 0); 2563** sqlite3_free(zSQL); 2564** </pre></blockquote> 2565** 2566** The code above will render a correct SQL statement in the zSQL 2567** variable even if the zText variable is a NULL pointer. 2568** 2569** ^(The "%w" formatting option is like "%q" except that it expects to 2570** be contained within double-quotes instead of single quotes, and it 2571** escapes the double-quote character instead of the single-quote 2572** character.)^ The "%w" formatting option is intended for safely inserting 2573** table and column names into a constructed SQL statement. 2574** 2575** ^(The "%z" formatting option works like "%s" but with the 2576** addition that after the string has been read and copied into 2577** the result, [sqlite3_free()] is called on the input string.)^ 2578*/ 2579char *sqlite3_mprintf(const char*,...); 2580char *sqlite3_vmprintf(const char*, va_list); 2581char *sqlite3_snprintf(int,char*,const char*, ...); 2582char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2583 2584/* 2585** CAPI3REF: Memory Allocation Subsystem 2586** 2587** The SQLite core uses these three routines for all of its own 2588** internal memory allocation needs. "Core" in the previous sentence 2589** does not include operating-system specific VFS implementation. The 2590** Windows VFS uses native malloc() and free() for some operations. 2591** 2592** ^The sqlite3_malloc() routine returns a pointer to a block 2593** of memory at least N bytes in length, where N is the parameter. 2594** ^If sqlite3_malloc() is unable to obtain sufficient free 2595** memory, it returns a NULL pointer. ^If the parameter N to 2596** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2597** a NULL pointer. 2598** 2599** ^The sqlite3_malloc64(N) routine works just like 2600** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2601** of a signed 32-bit integer. 2602** 2603** ^Calling sqlite3_free() with a pointer previously returned 2604** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2605** that it might be reused. ^The sqlite3_free() routine is 2606** a no-op if is called with a NULL pointer. Passing a NULL pointer 2607** to sqlite3_free() is harmless. After being freed, memory 2608** should neither be read nor written. Even reading previously freed 2609** memory might result in a segmentation fault or other severe error. 2610** Memory corruption, a segmentation fault, or other severe error 2611** might result if sqlite3_free() is called with a non-NULL pointer that 2612** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2613** 2614** ^The sqlite3_realloc(X,N) interface attempts to resize a 2615** prior memory allocation X to be at least N bytes. 2616** ^If the X parameter to sqlite3_realloc(X,N) 2617** is a NULL pointer then its behavior is identical to calling 2618** sqlite3_malloc(N). 2619** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2620** negative then the behavior is exactly the same as calling 2621** sqlite3_free(X). 2622** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2623** of at least N bytes in size or NULL if insufficient memory is available. 2624** ^If M is the size of the prior allocation, then min(N,M) bytes 2625** of the prior allocation are copied into the beginning of buffer returned 2626** by sqlite3_realloc(X,N) and the prior allocation is freed. 2627** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2628** prior allocation is not freed. 2629** 2630** ^The sqlite3_realloc64(X,N) interfaces works the same as 2631** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2632** of a 32-bit signed integer. 2633** 2634** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2635** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2636** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2637** ^The value returned by sqlite3_msize(X) might be larger than the number 2638** of bytes requested when X was allocated. ^If X is a NULL pointer then 2639** sqlite3_msize(X) returns zero. If X points to something that is not 2640** the beginning of memory allocation, or if it points to a formerly 2641** valid memory allocation that has now been freed, then the behavior 2642** of sqlite3_msize(X) is undefined and possibly harmful. 2643** 2644** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2645** sqlite3_malloc64(), and sqlite3_realloc64() 2646** is always aligned to at least an 8 byte boundary, or to a 2647** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2648** option is used. 2649** 2650** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2651** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2652** implementation of these routines to be omitted. That capability 2653** is no longer provided. Only built-in memory allocators can be used. 2654** 2655** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2656** the system malloc() and free() directly when converting 2657** filenames between the UTF-8 encoding used by SQLite 2658** and whatever filename encoding is used by the particular Windows 2659** installation. Memory allocation errors were detected, but 2660** they were reported back as [SQLITE_CANTOPEN] or 2661** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2662** 2663** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2664** must be either NULL or else pointers obtained from a prior 2665** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2666** not yet been released. 2667** 2668** The application must not read or write any part of 2669** a block of memory after it has been released using 2670** [sqlite3_free()] or [sqlite3_realloc()]. 2671*/ 2672void *sqlite3_malloc(int); 2673void *sqlite3_malloc64(sqlite3_uint64); 2674void *sqlite3_realloc(void*, int); 2675void *sqlite3_realloc64(void*, sqlite3_uint64); 2676void sqlite3_free(void*); 2677sqlite3_uint64 sqlite3_msize(void*); 2678 2679/* 2680** CAPI3REF: Memory Allocator Statistics 2681** 2682** SQLite provides these two interfaces for reporting on the status 2683** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2684** routines, which form the built-in memory allocation subsystem. 2685** 2686** ^The [sqlite3_memory_used()] routine returns the number of bytes 2687** of memory currently outstanding (malloced but not freed). 2688** ^The [sqlite3_memory_highwater()] routine returns the maximum 2689** value of [sqlite3_memory_used()] since the high-water mark 2690** was last reset. ^The values returned by [sqlite3_memory_used()] and 2691** [sqlite3_memory_highwater()] include any overhead 2692** added by SQLite in its implementation of [sqlite3_malloc()], 2693** but not overhead added by the any underlying system library 2694** routines that [sqlite3_malloc()] may call. 2695** 2696** ^The memory high-water mark is reset to the current value of 2697** [sqlite3_memory_used()] if and only if the parameter to 2698** [sqlite3_memory_highwater()] is true. ^The value returned 2699** by [sqlite3_memory_highwater(1)] is the high-water mark 2700** prior to the reset. 2701*/ 2702sqlite3_int64 sqlite3_memory_used(void); 2703sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2704 2705/* 2706** CAPI3REF: Pseudo-Random Number Generator 2707** 2708** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2709** select random [ROWID | ROWIDs] when inserting new records into a table that 2710** already uses the largest possible [ROWID]. The PRNG is also used for 2711** the build-in random() and randomblob() SQL functions. This interface allows 2712** applications to access the same PRNG for other purposes. 2713** 2714** ^A call to this routine stores N bytes of randomness into buffer P. 2715** ^The P parameter can be a NULL pointer. 2716** 2717** ^If this routine has not been previously called or if the previous 2718** call had N less than one or a NULL pointer for P, then the PRNG is 2719** seeded using randomness obtained from the xRandomness method of 2720** the default [sqlite3_vfs] object. 2721** ^If the previous call to this routine had an N of 1 or more and a 2722** non-NULL P then the pseudo-randomness is generated 2723** internally and without recourse to the [sqlite3_vfs] xRandomness 2724** method. 2725*/ 2726void sqlite3_randomness(int N, void *P); 2727 2728/* 2729** CAPI3REF: Compile-Time Authorization Callbacks 2730** METHOD: sqlite3 2731** KEYWORDS: {authorizer callback} 2732** 2733** ^This routine registers an authorizer callback with a particular 2734** [database connection], supplied in the first argument. 2735** ^The authorizer callback is invoked as SQL statements are being compiled 2736** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2737** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2738** and [sqlite3_prepare16_v3()]. ^At various 2739** points during the compilation process, as logic is being created 2740** to perform various actions, the authorizer callback is invoked to 2741** see if those actions are allowed. ^The authorizer callback should 2742** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2743** specific action but allow the SQL statement to continue to be 2744** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2745** rejected with an error. ^If the authorizer callback returns 2746** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2747** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2748** the authorizer will fail with an error message. 2749** 2750** When the callback returns [SQLITE_OK], that means the operation 2751** requested is ok. ^When the callback returns [SQLITE_DENY], the 2752** [sqlite3_prepare_v2()] or equivalent call that triggered the 2753** authorizer will fail with an error message explaining that 2754** access is denied. 2755** 2756** ^The first parameter to the authorizer callback is a copy of the third 2757** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2758** to the callback is an integer [SQLITE_COPY | action code] that specifies 2759** the particular action to be authorized. ^The third through sixth parameters 2760** to the callback are either NULL pointers or zero-terminated strings 2761** that contain additional details about the action to be authorized. 2762** Applications must always be prepared to encounter a NULL pointer in any 2763** of the third through the sixth parameters of the authorization callback. 2764** 2765** ^If the action code is [SQLITE_READ] 2766** and the callback returns [SQLITE_IGNORE] then the 2767** [prepared statement] statement is constructed to substitute 2768** a NULL value in place of the table column that would have 2769** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2770** return can be used to deny an untrusted user access to individual 2771** columns of a table. 2772** ^When a table is referenced by a [SELECT] but no column values are 2773** extracted from that table (for example in a query like 2774** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2775** is invoked once for that table with a column name that is an empty string. 2776** ^If the action code is [SQLITE_DELETE] and the callback returns 2777** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2778** [truncate optimization] is disabled and all rows are deleted individually. 2779** 2780** An authorizer is used when [sqlite3_prepare | preparing] 2781** SQL statements from an untrusted source, to ensure that the SQL statements 2782** do not try to access data they are not allowed to see, or that they do not 2783** try to execute malicious statements that damage the database. For 2784** example, an application may allow a user to enter arbitrary 2785** SQL queries for evaluation by a database. But the application does 2786** not want the user to be able to make arbitrary changes to the 2787** database. An authorizer could then be put in place while the 2788** user-entered SQL is being [sqlite3_prepare | prepared] that 2789** disallows everything except [SELECT] statements. 2790** 2791** Applications that need to process SQL from untrusted sources 2792** might also consider lowering resource limits using [sqlite3_limit()] 2793** and limiting database size using the [max_page_count] [PRAGMA] 2794** in addition to using an authorizer. 2795** 2796** ^(Only a single authorizer can be in place on a database connection 2797** at a time. Each call to sqlite3_set_authorizer overrides the 2798** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2799** The authorizer is disabled by default. 2800** 2801** The authorizer callback must not do anything that will modify 2802** the database connection that invoked the authorizer callback. 2803** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2804** database connections for the meaning of "modify" in this paragraph. 2805** 2806** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2807** statement might be re-prepared during [sqlite3_step()] due to a 2808** schema change. Hence, the application should ensure that the 2809** correct authorizer callback remains in place during the [sqlite3_step()]. 2810** 2811** ^Note that the authorizer callback is invoked only during 2812** [sqlite3_prepare()] or its variants. Authorization is not 2813** performed during statement evaluation in [sqlite3_step()], unless 2814** as stated in the previous paragraph, sqlite3_step() invokes 2815** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2816*/ 2817int sqlite3_set_authorizer( 2818 sqlite3*, 2819 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2820 void *pUserData 2821); 2822 2823/* 2824** CAPI3REF: Authorizer Return Codes 2825** 2826** The [sqlite3_set_authorizer | authorizer callback function] must 2827** return either [SQLITE_OK] or one of these two constants in order 2828** to signal SQLite whether or not the action is permitted. See the 2829** [sqlite3_set_authorizer | authorizer documentation] for additional 2830** information. 2831** 2832** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2833** returned from the [sqlite3_vtab_on_conflict()] interface. 2834*/ 2835#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2836#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2837 2838/* 2839** CAPI3REF: Authorizer Action Codes 2840** 2841** The [sqlite3_set_authorizer()] interface registers a callback function 2842** that is invoked to authorize certain SQL statement actions. The 2843** second parameter to the callback is an integer code that specifies 2844** what action is being authorized. These are the integer action codes that 2845** the authorizer callback may be passed. 2846** 2847** These action code values signify what kind of operation is to be 2848** authorized. The 3rd and 4th parameters to the authorization 2849** callback function will be parameters or NULL depending on which of these 2850** codes is used as the second parameter. ^(The 5th parameter to the 2851** authorizer callback is the name of the database ("main", "temp", 2852** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2853** is the name of the inner-most trigger or view that is responsible for 2854** the access attempt or NULL if this access attempt is directly from 2855** top-level SQL code. 2856*/ 2857/******************************************* 3rd ************ 4th ***********/ 2858#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2859#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2860#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2861#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2862#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2863#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2864#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2865#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2866#define SQLITE_DELETE 9 /* Table Name NULL */ 2867#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2868#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2869#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2870#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2871#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2872#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2873#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2874#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2875#define SQLITE_INSERT 18 /* Table Name NULL */ 2876#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2877#define SQLITE_READ 20 /* Table Name Column Name */ 2878#define SQLITE_SELECT 21 /* NULL NULL */ 2879#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2880#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2881#define SQLITE_ATTACH 24 /* Filename NULL */ 2882#define SQLITE_DETACH 25 /* Database Name NULL */ 2883#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2884#define SQLITE_REINDEX 27 /* Index Name NULL */ 2885#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2886#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2887#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2888#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2889#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2890#define SQLITE_COPY 0 /* No longer used */ 2891#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2892 2893/* 2894** CAPI3REF: Tracing And Profiling Functions 2895** METHOD: sqlite3 2896** 2897** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2898** instead of the routines described here. 2899** 2900** These routines register callback functions that can be used for 2901** tracing and profiling the execution of SQL statements. 2902** 2903** ^The callback function registered by sqlite3_trace() is invoked at 2904** various times when an SQL statement is being run by [sqlite3_step()]. 2905** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2906** SQL statement text as the statement first begins executing. 2907** ^(Additional sqlite3_trace() callbacks might occur 2908** as each triggered subprogram is entered. The callbacks for triggers 2909** contain a UTF-8 SQL comment that identifies the trigger.)^ 2910** 2911** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2912** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2913** 2914** ^The callback function registered by sqlite3_profile() is invoked 2915** as each SQL statement finishes. ^The profile callback contains 2916** the original statement text and an estimate of wall-clock time 2917** of how long that statement took to run. ^The profile callback 2918** time is in units of nanoseconds, however the current implementation 2919** is only capable of millisecond resolution so the six least significant 2920** digits in the time are meaningless. Future versions of SQLite 2921** might provide greater resolution on the profiler callback. The 2922** sqlite3_profile() function is considered experimental and is 2923** subject to change in future versions of SQLite. 2924*/ 2925SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2926 void(*xTrace)(void*,const char*), void*); 2927SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2928 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2929 2930/* 2931** CAPI3REF: SQL Trace Event Codes 2932** KEYWORDS: SQLITE_TRACE 2933** 2934** These constants identify classes of events that can be monitored 2935** using the [sqlite3_trace_v2()] tracing logic. The third argument 2936** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2937** the following constants. ^The first argument to the trace callback 2938** is one of the following constants. 2939** 2940** New tracing constants may be added in future releases. 2941** 2942** ^A trace callback has four arguments: xCallback(T,C,P,X). 2943** ^The T argument is one of the integer type codes above. 2944** ^The C argument is a copy of the context pointer passed in as the 2945** fourth argument to [sqlite3_trace_v2()]. 2946** The P and X arguments are pointers whose meanings depend on T. 2947** 2948** <dl> 2949** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2950** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2951** first begins running and possibly at other times during the 2952** execution of the prepared statement, such as at the start of each 2953** trigger subprogram. ^The P argument is a pointer to the 2954** [prepared statement]. ^The X argument is a pointer to a string which 2955** is the unexpanded SQL text of the prepared statement or an SQL comment 2956** that indicates the invocation of a trigger. ^The callback can compute 2957** the same text that would have been returned by the legacy [sqlite3_trace()] 2958** interface by using the X argument when X begins with "--" and invoking 2959** [sqlite3_expanded_sql(P)] otherwise. 2960** 2961** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2962** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2963** information as is provided by the [sqlite3_profile()] callback. 2964** ^The P argument is a pointer to the [prepared statement] and the 2965** X argument points to a 64-bit integer which is the estimated of 2966** the number of nanosecond that the prepared statement took to run. 2967** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2968** 2969** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2970** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2971** statement generates a single row of result. 2972** ^The P argument is a pointer to the [prepared statement] and the 2973** X argument is unused. 2974** 2975** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2976** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2977** connection closes. 2978** ^The P argument is a pointer to the [database connection] object 2979** and the X argument is unused. 2980** </dl> 2981*/ 2982#define SQLITE_TRACE_STMT 0x01 2983#define SQLITE_TRACE_PROFILE 0x02 2984#define SQLITE_TRACE_ROW 0x04 2985#define SQLITE_TRACE_CLOSE 0x08 2986 2987/* 2988** CAPI3REF: SQL Trace Hook 2989** METHOD: sqlite3 2990** 2991** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2992** function X against [database connection] D, using property mask M 2993** and context pointer P. ^If the X callback is 2994** NULL or if the M mask is zero, then tracing is disabled. The 2995** M argument should be the bitwise OR-ed combination of 2996** zero or more [SQLITE_TRACE] constants. 2997** 2998** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2999** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3000** 3001** ^The X callback is invoked whenever any of the events identified by 3002** mask M occur. ^The integer return value from the callback is currently 3003** ignored, though this may change in future releases. Callback 3004** implementations should return zero to ensure future compatibility. 3005** 3006** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3007** ^The T argument is one of the [SQLITE_TRACE] 3008** constants to indicate why the callback was invoked. 3009** ^The C argument is a copy of the context pointer. 3010** The P and X arguments are pointers whose meanings depend on T. 3011** 3012** The sqlite3_trace_v2() interface is intended to replace the legacy 3013** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3014** are deprecated. 3015*/ 3016int sqlite3_trace_v2( 3017 sqlite3*, 3018 unsigned uMask, 3019 int(*xCallback)(unsigned,void*,void*,void*), 3020 void *pCtx 3021); 3022 3023/* 3024** CAPI3REF: Query Progress Callbacks 3025** METHOD: sqlite3 3026** 3027** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3028** function X to be invoked periodically during long running calls to 3029** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3030** database connection D. An example use for this 3031** interface is to keep a GUI updated during a large query. 3032** 3033** ^The parameter P is passed through as the only parameter to the 3034** callback function X. ^The parameter N is the approximate number of 3035** [virtual machine instructions] that are evaluated between successive 3036** invocations of the callback X. ^If N is less than one then the progress 3037** handler is disabled. 3038** 3039** ^Only a single progress handler may be defined at one time per 3040** [database connection]; setting a new progress handler cancels the 3041** old one. ^Setting parameter X to NULL disables the progress handler. 3042** ^The progress handler is also disabled by setting N to a value less 3043** than 1. 3044** 3045** ^If the progress callback returns non-zero, the operation is 3046** interrupted. This feature can be used to implement a 3047** "Cancel" button on a GUI progress dialog box. 3048** 3049** The progress handler callback must not do anything that will modify 3050** the database connection that invoked the progress handler. 3051** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3052** database connections for the meaning of "modify" in this paragraph. 3053** 3054*/ 3055void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3056 3057/* 3058** CAPI3REF: Opening A New Database Connection 3059** CONSTRUCTOR: sqlite3 3060** 3061** ^These routines open an SQLite database file as specified by the 3062** filename argument. ^The filename argument is interpreted as UTF-8 for 3063** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3064** order for sqlite3_open16(). ^(A [database connection] handle is usually 3065** returned in *ppDb, even if an error occurs. The only exception is that 3066** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3067** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3068** object.)^ ^(If the database is opened (and/or created) successfully, then 3069** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3070** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3071** an English language description of the error following a failure of any 3072** of the sqlite3_open() routines. 3073** 3074** ^The default encoding will be UTF-8 for databases created using 3075** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3076** created using sqlite3_open16() will be UTF-16 in the native byte order. 3077** 3078** Whether or not an error occurs when it is opened, resources 3079** associated with the [database connection] handle should be released by 3080** passing it to [sqlite3_close()] when it is no longer required. 3081** 3082** The sqlite3_open_v2() interface works like sqlite3_open() 3083** except that it accepts two additional parameters for additional control 3084** over the new database connection. ^(The flags parameter to 3085** sqlite3_open_v2() can take one of 3086** the following three values, optionally combined with the 3087** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3088** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3089** 3090** <dl> 3091** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3092** <dd>The database is opened in read-only mode. If the database does not 3093** already exist, an error is returned.</dd>)^ 3094** 3095** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3096** <dd>The database is opened for reading and writing if possible, or reading 3097** only if the file is write protected by the operating system. In either 3098** case the database must already exist, otherwise an error is returned.</dd>)^ 3099** 3100** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3101** <dd>The database is opened for reading and writing, and is created if 3102** it does not already exist. This is the behavior that is always used for 3103** sqlite3_open() and sqlite3_open16().</dd>)^ 3104** </dl> 3105** 3106** If the 3rd parameter to sqlite3_open_v2() is not one of the 3107** combinations shown above optionally combined with other 3108** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3109** then the behavior is undefined. 3110** 3111** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3112** opens in the multi-thread [threading mode] as long as the single-thread 3113** mode has not been set at compile-time or start-time. ^If the 3114** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3115** in the serialized [threading mode] unless single-thread was 3116** previously selected at compile-time or start-time. 3117** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3118** eligible to use [shared cache mode], regardless of whether or not shared 3119** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3120** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3121** participate in [shared cache mode] even if it is enabled. 3122** 3123** ^The fourth parameter to sqlite3_open_v2() is the name of the 3124** [sqlite3_vfs] object that defines the operating system interface that 3125** the new database connection should use. ^If the fourth parameter is 3126** a NULL pointer then the default [sqlite3_vfs] object is used. 3127** 3128** ^If the filename is ":memory:", then a private, temporary in-memory database 3129** is created for the connection. ^This in-memory database will vanish when 3130** the database connection is closed. Future versions of SQLite might 3131** make use of additional special filenames that begin with the ":" character. 3132** It is recommended that when a database filename actually does begin with 3133** a ":" character you should prefix the filename with a pathname such as 3134** "./" to avoid ambiguity. 3135** 3136** ^If the filename is an empty string, then a private, temporary 3137** on-disk database will be created. ^This private database will be 3138** automatically deleted as soon as the database connection is closed. 3139** 3140** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3141** 3142** ^If [URI filename] interpretation is enabled, and the filename argument 3143** begins with "file:", then the filename is interpreted as a URI. ^URI 3144** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3145** set in the third argument to sqlite3_open_v2(), or if it has 3146** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3147** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3148** URI filename interpretation is turned off 3149** by default, but future releases of SQLite might enable URI filename 3150** interpretation by default. See "[URI filenames]" for additional 3151** information. 3152** 3153** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3154** authority, then it must be either an empty string or the string 3155** "localhost". ^If the authority is not an empty string or "localhost", an 3156** error is returned to the caller. ^The fragment component of a URI, if 3157** present, is ignored. 3158** 3159** ^SQLite uses the path component of the URI as the name of the disk file 3160** which contains the database. ^If the path begins with a '/' character, 3161** then it is interpreted as an absolute path. ^If the path does not begin 3162** with a '/' (meaning that the authority section is omitted from the URI) 3163** then the path is interpreted as a relative path. 3164** ^(On windows, the first component of an absolute path 3165** is a drive specification (e.g. "C:").)^ 3166** 3167** [[core URI query parameters]] 3168** The query component of a URI may contain parameters that are interpreted 3169** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3170** SQLite and its built-in [VFSes] interpret the 3171** following query parameters: 3172** 3173** <ul> 3174** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3175** a VFS object that provides the operating system interface that should 3176** be used to access the database file on disk. ^If this option is set to 3177** an empty string the default VFS object is used. ^Specifying an unknown 3178** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3179** present, then the VFS specified by the option takes precedence over 3180** the value passed as the fourth parameter to sqlite3_open_v2(). 3181** 3182** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3183** "rwc", or "memory". Attempting to set it to any other value is 3184** an error)^. 3185** ^If "ro" is specified, then the database is opened for read-only 3186** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3187** third argument to sqlite3_open_v2(). ^If the mode option is set to 3188** "rw", then the database is opened for read-write (but not create) 3189** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3190** been set. ^Value "rwc" is equivalent to setting both 3191** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3192** set to "memory" then a pure [in-memory database] that never reads 3193** or writes from disk is used. ^It is an error to specify a value for 3194** the mode parameter that is less restrictive than that specified by 3195** the flags passed in the third parameter to sqlite3_open_v2(). 3196** 3197** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3198** "private". ^Setting it to "shared" is equivalent to setting the 3199** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3200** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3201** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3202** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3203** a URI filename, its value overrides any behavior requested by setting 3204** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3205** 3206** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3207** [powersafe overwrite] property does or does not apply to the 3208** storage media on which the database file resides. 3209** 3210** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3211** which if set disables file locking in rollback journal modes. This 3212** is useful for accessing a database on a filesystem that does not 3213** support locking. Caution: Database corruption might result if two 3214** or more processes write to the same database and any one of those 3215** processes uses nolock=1. 3216** 3217** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3218** parameter that indicates that the database file is stored on 3219** read-only media. ^When immutable is set, SQLite assumes that the 3220** database file cannot be changed, even by a process with higher 3221** privilege, and so the database is opened read-only and all locking 3222** and change detection is disabled. Caution: Setting the immutable 3223** property on a database file that does in fact change can result 3224** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3225** See also: [SQLITE_IOCAP_IMMUTABLE]. 3226** 3227** </ul> 3228** 3229** ^Specifying an unknown parameter in the query component of a URI is not an 3230** error. Future versions of SQLite might understand additional query 3231** parameters. See "[query parameters with special meaning to SQLite]" for 3232** additional information. 3233** 3234** [[URI filename examples]] <h3>URI filename examples</h3> 3235** 3236** <table border="1" align=center cellpadding=5> 3237** <tr><th> URI filenames <th> Results 3238** <tr><td> file:data.db <td> 3239** Open the file "data.db" in the current directory. 3240** <tr><td> file:/home/fred/data.db<br> 3241** file:///home/fred/data.db <br> 3242** file://localhost/home/fred/data.db <br> <td> 3243** Open the database file "/home/fred/data.db". 3244** <tr><td> file://darkstar/home/fred/data.db <td> 3245** An error. "darkstar" is not a recognized authority. 3246** <tr><td style="white-space:nowrap"> 3247** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3248** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3249** C:. Note that the %20 escaping in this example is not strictly 3250** necessary - space characters can be used literally 3251** in URI filenames. 3252** <tr><td> file:data.db?mode=ro&cache=private <td> 3253** Open file "data.db" in the current directory for read-only access. 3254** Regardless of whether or not shared-cache mode is enabled by 3255** default, use a private cache. 3256** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3257** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3258** that uses dot-files in place of posix advisory locking. 3259** <tr><td> file:data.db?mode=readonly <td> 3260** An error. "readonly" is not a valid option for the "mode" parameter. 3261** </table> 3262** 3263** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3264** query components of a URI. A hexadecimal escape sequence consists of a 3265** percent sign - "%" - followed by exactly two hexadecimal digits 3266** specifying an octet value. ^Before the path or query components of a 3267** URI filename are interpreted, they are encoded using UTF-8 and all 3268** hexadecimal escape sequences replaced by a single byte containing the 3269** corresponding octet. If this process generates an invalid UTF-8 encoding, 3270** the results are undefined. 3271** 3272** <b>Note to Windows users:</b> The encoding used for the filename argument 3273** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3274** codepage is currently defined. Filenames containing international 3275** characters must be converted to UTF-8 prior to passing them into 3276** sqlite3_open() or sqlite3_open_v2(). 3277** 3278** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3279** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3280** features that require the use of temporary files may fail. 3281** 3282** See also: [sqlite3_temp_directory] 3283*/ 3284int sqlite3_open( 3285 const char *filename, /* Database filename (UTF-8) */ 3286 sqlite3 **ppDb /* OUT: SQLite db handle */ 3287); 3288int sqlite3_open16( 3289 const void *filename, /* Database filename (UTF-16) */ 3290 sqlite3 **ppDb /* OUT: SQLite db handle */ 3291); 3292int sqlite3_open_v2( 3293 const char *filename, /* Database filename (UTF-8) */ 3294 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3295 int flags, /* Flags */ 3296 const char *zVfs /* Name of VFS module to use */ 3297); 3298 3299/* 3300** CAPI3REF: Obtain Values For URI Parameters 3301** 3302** These are utility routines, useful to VFS implementations, that check 3303** to see if a database file was a URI that contained a specific query 3304** parameter, and if so obtains the value of that query parameter. 3305** 3306** If F is the database filename pointer passed into the xOpen() method of 3307** a VFS implementation when the flags parameter to xOpen() has one or 3308** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3309** P is the name of the query parameter, then 3310** sqlite3_uri_parameter(F,P) returns the value of the P 3311** parameter if it exists or a NULL pointer if P does not appear as a 3312** query parameter on F. If P is a query parameter of F 3313** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3314** a pointer to an empty string. 3315** 3316** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3317** parameter and returns true (1) or false (0) according to the value 3318** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3319** value of query parameter P is one of "yes", "true", or "on" in any 3320** case or if the value begins with a non-zero number. The 3321** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3322** query parameter P is one of "no", "false", or "off" in any case or 3323** if the value begins with a numeric zero. If P is not a query 3324** parameter on F or if the value of P is does not match any of the 3325** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3326** 3327** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3328** 64-bit signed integer and returns that integer, or D if P does not 3329** exist. If the value of P is something other than an integer, then 3330** zero is returned. 3331** 3332** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3333** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3334** is not a database file pathname pointer that SQLite passed into the xOpen 3335** VFS method, then the behavior of this routine is undefined and probably 3336** undesirable. 3337*/ 3338const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3339int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3340sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3341 3342 3343/* 3344** CAPI3REF: Error Codes And Messages 3345** METHOD: sqlite3 3346** 3347** ^If the most recent sqlite3_* API call associated with 3348** [database connection] D failed, then the sqlite3_errcode(D) interface 3349** returns the numeric [result code] or [extended result code] for that 3350** API call. 3351** If the most recent API call was successful, 3352** then the return value from sqlite3_errcode() is undefined. 3353** ^The sqlite3_extended_errcode() 3354** interface is the same except that it always returns the 3355** [extended result code] even when extended result codes are 3356** disabled. 3357** 3358** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3359** text that describes the error, as either UTF-8 or UTF-16 respectively. 3360** ^(Memory to hold the error message string is managed internally. 3361** The application does not need to worry about freeing the result. 3362** However, the error string might be overwritten or deallocated by 3363** subsequent calls to other SQLite interface functions.)^ 3364** 3365** ^The sqlite3_errstr() interface returns the English-language text 3366** that describes the [result code], as UTF-8. 3367** ^(Memory to hold the error message string is managed internally 3368** and must not be freed by the application)^. 3369** 3370** When the serialized [threading mode] is in use, it might be the 3371** case that a second error occurs on a separate thread in between 3372** the time of the first error and the call to these interfaces. 3373** When that happens, the second error will be reported since these 3374** interfaces always report the most recent result. To avoid 3375** this, each thread can obtain exclusive use of the [database connection] D 3376** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3377** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3378** all calls to the interfaces listed here are completed. 3379** 3380** If an interface fails with SQLITE_MISUSE, that means the interface 3381** was invoked incorrectly by the application. In that case, the 3382** error code and message may or may not be set. 3383*/ 3384int sqlite3_errcode(sqlite3 *db); 3385int sqlite3_extended_errcode(sqlite3 *db); 3386const char *sqlite3_errmsg(sqlite3*); 3387const void *sqlite3_errmsg16(sqlite3*); 3388const char *sqlite3_errstr(int); 3389 3390/* 3391** CAPI3REF: Prepared Statement Object 3392** KEYWORDS: {prepared statement} {prepared statements} 3393** 3394** An instance of this object represents a single SQL statement that 3395** has been compiled into binary form and is ready to be evaluated. 3396** 3397** Think of each SQL statement as a separate computer program. The 3398** original SQL text is source code. A prepared statement object 3399** is the compiled object code. All SQL must be converted into a 3400** prepared statement before it can be run. 3401** 3402** The life-cycle of a prepared statement object usually goes like this: 3403** 3404** <ol> 3405** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3406** <li> Bind values to [parameters] using the sqlite3_bind_*() 3407** interfaces. 3408** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3409** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3410** to step 2. Do this zero or more times. 3411** <li> Destroy the object using [sqlite3_finalize()]. 3412** </ol> 3413*/ 3414typedef struct sqlite3_stmt sqlite3_stmt; 3415 3416/* 3417** CAPI3REF: Run-time Limits 3418** METHOD: sqlite3 3419** 3420** ^(This interface allows the size of various constructs to be limited 3421** on a connection by connection basis. The first parameter is the 3422** [database connection] whose limit is to be set or queried. The 3423** second parameter is one of the [limit categories] that define a 3424** class of constructs to be size limited. The third parameter is the 3425** new limit for that construct.)^ 3426** 3427** ^If the new limit is a negative number, the limit is unchanged. 3428** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3429** [limits | hard upper bound] 3430** set at compile-time by a C preprocessor macro called 3431** [limits | SQLITE_MAX_<i>NAME</i>]. 3432** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3433** ^Attempts to increase a limit above its hard upper bound are 3434** silently truncated to the hard upper bound. 3435** 3436** ^Regardless of whether or not the limit was changed, the 3437** [sqlite3_limit()] interface returns the prior value of the limit. 3438** ^Hence, to find the current value of a limit without changing it, 3439** simply invoke this interface with the third parameter set to -1. 3440** 3441** Run-time limits are intended for use in applications that manage 3442** both their own internal database and also databases that are controlled 3443** by untrusted external sources. An example application might be a 3444** web browser that has its own databases for storing history and 3445** separate databases controlled by JavaScript applications downloaded 3446** off the Internet. The internal databases can be given the 3447** large, default limits. Databases managed by external sources can 3448** be given much smaller limits designed to prevent a denial of service 3449** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3450** interface to further control untrusted SQL. The size of the database 3451** created by an untrusted script can be contained using the 3452** [max_page_count] [PRAGMA]. 3453** 3454** New run-time limit categories may be added in future releases. 3455*/ 3456int sqlite3_limit(sqlite3*, int id, int newVal); 3457 3458/* 3459** CAPI3REF: Run-Time Limit Categories 3460** KEYWORDS: {limit category} {*limit categories} 3461** 3462** These constants define various performance limits 3463** that can be lowered at run-time using [sqlite3_limit()]. 3464** The synopsis of the meanings of the various limits is shown below. 3465** Additional information is available at [limits | Limits in SQLite]. 3466** 3467** <dl> 3468** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3469** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3470** 3471** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3472** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3473** 3474** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3475** <dd>The maximum number of columns in a table definition or in the 3476** result set of a [SELECT] or the maximum number of columns in an index 3477** or in an ORDER BY or GROUP BY clause.</dd>)^ 3478** 3479** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3480** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3481** 3482** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3483** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3484** 3485** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3486** <dd>The maximum number of instructions in a virtual machine program 3487** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3488** the equivalent tries to allocate space for more than this many opcodes 3489** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3490** 3491** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3492** <dd>The maximum number of arguments on a function.</dd>)^ 3493** 3494** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3495** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3496** 3497** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3498** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3499** <dd>The maximum length of the pattern argument to the [LIKE] or 3500** [GLOB] operators.</dd>)^ 3501** 3502** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3503** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3504** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3505** 3506** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3507** <dd>The maximum depth of recursion for triggers.</dd>)^ 3508** 3509** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3510** <dd>The maximum number of auxiliary worker threads that a single 3511** [prepared statement] may start.</dd>)^ 3512** </dl> 3513*/ 3514#define SQLITE_LIMIT_LENGTH 0 3515#define SQLITE_LIMIT_SQL_LENGTH 1 3516#define SQLITE_LIMIT_COLUMN 2 3517#define SQLITE_LIMIT_EXPR_DEPTH 3 3518#define SQLITE_LIMIT_COMPOUND_SELECT 4 3519#define SQLITE_LIMIT_VDBE_OP 5 3520#define SQLITE_LIMIT_FUNCTION_ARG 6 3521#define SQLITE_LIMIT_ATTACHED 7 3522#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3523#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3524#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3525#define SQLITE_LIMIT_WORKER_THREADS 11 3526 3527/* 3528** CAPI3REF: Prepare Flags 3529** 3530** These constants define various flags that can be passed into 3531** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3532** [sqlite3_prepare16_v3()] interfaces. 3533** 3534** New flags may be added in future releases of SQLite. 3535** 3536** <dl> 3537** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3538** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3539** that the prepared statement will be retained for a long time and 3540** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3541** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3542** be used just once or at most a few times and then destroyed using 3543** [sqlite3_finalize()] relatively soon. The current implementation acts 3544** on this hint by avoiding the use of [lookaside memory] so as not to 3545** deplete the limited store of lookaside memory. Future versions of 3546** SQLite may act on this hint differently. 3547** </dl> 3548*/ 3549#define SQLITE_PREPARE_PERSISTENT 0x01 3550 3551/* 3552** CAPI3REF: Compiling An SQL Statement 3553** KEYWORDS: {SQL statement compiler} 3554** METHOD: sqlite3 3555** CONSTRUCTOR: sqlite3_stmt 3556** 3557** To execute an SQL statement, it must first be compiled into a byte-code 3558** program using one of these routines. Or, in other words, these routines 3559** are constructors for the [prepared statement] object. 3560** 3561** The preferred routine to use is [sqlite3_prepare_v2()]. The 3562** [sqlite3_prepare()] interface is legacy and should be avoided. 3563** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3564** for special purposes. 3565** 3566** The use of the UTF-8 interfaces is preferred, as SQLite currently 3567** does all parsing using UTF-8. The UTF-16 interfaces are provided 3568** as a convenience. The UTF-16 interfaces work by converting the 3569** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3570** 3571** The first argument, "db", is a [database connection] obtained from a 3572** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3573** [sqlite3_open16()]. The database connection must not have been closed. 3574** 3575** The second argument, "zSql", is the statement to be compiled, encoded 3576** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3577** and sqlite3_prepare_v3() 3578** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3579** and sqlite3_prepare16_v3() use UTF-16. 3580** 3581** ^If the nByte argument is negative, then zSql is read up to the 3582** first zero terminator. ^If nByte is positive, then it is the 3583** number of bytes read from zSql. ^If nByte is zero, then no prepared 3584** statement is generated. 3585** If the caller knows that the supplied string is nul-terminated, then 3586** there is a small performance advantage to passing an nByte parameter that 3587** is the number of bytes in the input string <i>including</i> 3588** the nul-terminator. 3589** 3590** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3591** past the end of the first SQL statement in zSql. These routines only 3592** compile the first statement in zSql, so *pzTail is left pointing to 3593** what remains uncompiled. 3594** 3595** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3596** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3597** to NULL. ^If the input text contains no SQL (if the input is an empty 3598** string or a comment) then *ppStmt is set to NULL. 3599** The calling procedure is responsible for deleting the compiled 3600** SQL statement using [sqlite3_finalize()] after it has finished with it. 3601** ppStmt may not be NULL. 3602** 3603** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3604** otherwise an [error code] is returned. 3605** 3606** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3607** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3608** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3609** are retained for backwards compatibility, but their use is discouraged. 3610** ^In the "vX" interfaces, the prepared statement 3611** that is returned (the [sqlite3_stmt] object) contains a copy of the 3612** original SQL text. This causes the [sqlite3_step()] interface to 3613** behave differently in three ways: 3614** 3615** <ol> 3616** <li> 3617** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3618** always used to do, [sqlite3_step()] will automatically recompile the SQL 3619** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3620** retries will occur before sqlite3_step() gives up and returns an error. 3621** </li> 3622** 3623** <li> 3624** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3625** [error codes] or [extended error codes]. ^The legacy behavior was that 3626** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3627** and the application would have to make a second call to [sqlite3_reset()] 3628** in order to find the underlying cause of the problem. With the "v2" prepare 3629** interfaces, the underlying reason for the error is returned immediately. 3630** </li> 3631** 3632** <li> 3633** ^If the specific value bound to [parameter | host parameter] in the 3634** WHERE clause might influence the choice of query plan for a statement, 3635** then the statement will be automatically recompiled, as if there had been 3636** a schema change, on the first [sqlite3_step()] call following any change 3637** to the [sqlite3_bind_text | bindings] of that [parameter]. 3638** ^The specific value of WHERE-clause [parameter] might influence the 3639** choice of query plan if the parameter is the left-hand side of a [LIKE] 3640** or [GLOB] operator or if the parameter is compared to an indexed column 3641** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3642** </li> 3643** 3644** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3645** the extra prepFlags parameter, which is a bit array consisting of zero or 3646** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3647** sqlite3_prepare_v2() interface works exactly the same as 3648** sqlite3_prepare_v3() with a zero prepFlags parameter. 3649** </ol> 3650*/ 3651int sqlite3_prepare( 3652 sqlite3 *db, /* Database handle */ 3653 const char *zSql, /* SQL statement, UTF-8 encoded */ 3654 int nByte, /* Maximum length of zSql in bytes. */ 3655 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3656 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3657); 3658int sqlite3_prepare_v2( 3659 sqlite3 *db, /* Database handle */ 3660 const char *zSql, /* SQL statement, UTF-8 encoded */ 3661 int nByte, /* Maximum length of zSql in bytes. */ 3662 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3663 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3664); 3665int sqlite3_prepare_v3( 3666 sqlite3 *db, /* Database handle */ 3667 const char *zSql, /* SQL statement, UTF-8 encoded */ 3668 int nByte, /* Maximum length of zSql in bytes. */ 3669 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3670 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3671 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3672); 3673int sqlite3_prepare16( 3674 sqlite3 *db, /* Database handle */ 3675 const void *zSql, /* SQL statement, UTF-16 encoded */ 3676 int nByte, /* Maximum length of zSql in bytes. */ 3677 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3678 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3679); 3680int sqlite3_prepare16_v2( 3681 sqlite3 *db, /* Database handle */ 3682 const void *zSql, /* SQL statement, UTF-16 encoded */ 3683 int nByte, /* Maximum length of zSql in bytes. */ 3684 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3685 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3686); 3687int sqlite3_prepare16_v3( 3688 sqlite3 *db, /* Database handle */ 3689 const void *zSql, /* SQL statement, UTF-16 encoded */ 3690 int nByte, /* Maximum length of zSql in bytes. */ 3691 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3692 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3693 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3694); 3695 3696/* 3697** CAPI3REF: Retrieving Statement SQL 3698** METHOD: sqlite3_stmt 3699** 3700** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3701** SQL text used to create [prepared statement] P if P was 3702** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3703** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3704** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3705** string containing the SQL text of prepared statement P with 3706** [bound parameters] expanded. 3707** 3708** ^(For example, if a prepared statement is created using the SQL 3709** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3710** and parameter :xyz is unbound, then sqlite3_sql() will return 3711** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3712** will return "SELECT 2345,NULL".)^ 3713** 3714** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3715** is available to hold the result, or if the result would exceed the 3716** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3717** 3718** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3719** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3720** option causes sqlite3_expanded_sql() to always return NULL. 3721** 3722** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3723** automatically freed when the prepared statement is finalized. 3724** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3725** is obtained from [sqlite3_malloc()] and must be free by the application 3726** by passing it to [sqlite3_free()]. 3727*/ 3728const char *sqlite3_sql(sqlite3_stmt *pStmt); 3729char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3730 3731/* 3732** CAPI3REF: Determine If An SQL Statement Writes The Database 3733** METHOD: sqlite3_stmt 3734** 3735** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3736** and only if the [prepared statement] X makes no direct changes to 3737** the content of the database file. 3738** 3739** Note that [application-defined SQL functions] or 3740** [virtual tables] might change the database indirectly as a side effect. 3741** ^(For example, if an application defines a function "eval()" that 3742** calls [sqlite3_exec()], then the following SQL statement would 3743** change the database file through side-effects: 3744** 3745** <blockquote><pre> 3746** SELECT eval('DELETE FROM t1') FROM t2; 3747** </pre></blockquote> 3748** 3749** But because the [SELECT] statement does not change the database file 3750** directly, sqlite3_stmt_readonly() would still return true.)^ 3751** 3752** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3753** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3754** since the statements themselves do not actually modify the database but 3755** rather they control the timing of when other statements modify the 3756** database. ^The [ATTACH] and [DETACH] statements also cause 3757** sqlite3_stmt_readonly() to return true since, while those statements 3758** change the configuration of a database connection, they do not make 3759** changes to the content of the database files on disk. 3760** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3761** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3762** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3763** sqlite3_stmt_readonly() returns false for those commands. 3764*/ 3765int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3766 3767/* 3768** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3769** METHOD: sqlite3_stmt 3770** 3771** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3772** [prepared statement] S has been stepped at least once using 3773** [sqlite3_step(S)] but has neither run to completion (returned 3774** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3775** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3776** interface returns false if S is a NULL pointer. If S is not a 3777** NULL pointer and is not a pointer to a valid [prepared statement] 3778** object, then the behavior is undefined and probably undesirable. 3779** 3780** This interface can be used in combination [sqlite3_next_stmt()] 3781** to locate all prepared statements associated with a database 3782** connection that are in need of being reset. This can be used, 3783** for example, in diagnostic routines to search for prepared 3784** statements that are holding a transaction open. 3785*/ 3786int sqlite3_stmt_busy(sqlite3_stmt*); 3787 3788/* 3789** CAPI3REF: Dynamically Typed Value Object 3790** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3791** 3792** SQLite uses the sqlite3_value object to represent all values 3793** that can be stored in a database table. SQLite uses dynamic typing 3794** for the values it stores. ^Values stored in sqlite3_value objects 3795** can be integers, floating point values, strings, BLOBs, or NULL. 3796** 3797** An sqlite3_value object may be either "protected" or "unprotected". 3798** Some interfaces require a protected sqlite3_value. Other interfaces 3799** will accept either a protected or an unprotected sqlite3_value. 3800** Every interface that accepts sqlite3_value arguments specifies 3801** whether or not it requires a protected sqlite3_value. The 3802** [sqlite3_value_dup()] interface can be used to construct a new 3803** protected sqlite3_value from an unprotected sqlite3_value. 3804** 3805** The terms "protected" and "unprotected" refer to whether or not 3806** a mutex is held. An internal mutex is held for a protected 3807** sqlite3_value object but no mutex is held for an unprotected 3808** sqlite3_value object. If SQLite is compiled to be single-threaded 3809** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3810** or if SQLite is run in one of reduced mutex modes 3811** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3812** then there is no distinction between protected and unprotected 3813** sqlite3_value objects and they can be used interchangeably. However, 3814** for maximum code portability it is recommended that applications 3815** still make the distinction between protected and unprotected 3816** sqlite3_value objects even when not strictly required. 3817** 3818** ^The sqlite3_value objects that are passed as parameters into the 3819** implementation of [application-defined SQL functions] are protected. 3820** ^The sqlite3_value object returned by 3821** [sqlite3_column_value()] is unprotected. 3822** Unprotected sqlite3_value objects may only be used as arguments 3823** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3824** [sqlite3_value_dup()]. 3825** The [sqlite3_value_blob | sqlite3_value_type()] family of 3826** interfaces require protected sqlite3_value objects. 3827*/ 3828typedef struct sqlite3_value sqlite3_value; 3829 3830/* 3831** CAPI3REF: SQL Function Context Object 3832** 3833** The context in which an SQL function executes is stored in an 3834** sqlite3_context object. ^A pointer to an sqlite3_context object 3835** is always first parameter to [application-defined SQL functions]. 3836** The application-defined SQL function implementation will pass this 3837** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3838** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3839** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3840** and/or [sqlite3_set_auxdata()]. 3841*/ 3842typedef struct sqlite3_context sqlite3_context; 3843 3844/* 3845** CAPI3REF: Binding Values To Prepared Statements 3846** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3847** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3848** METHOD: sqlite3_stmt 3849** 3850** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3851** literals may be replaced by a [parameter] that matches one of following 3852** templates: 3853** 3854** <ul> 3855** <li> ? 3856** <li> ?NNN 3857** <li> :VVV 3858** <li> @VVV 3859** <li> $VVV 3860** </ul> 3861** 3862** In the templates above, NNN represents an integer literal, 3863** and VVV represents an alphanumeric identifier.)^ ^The values of these 3864** parameters (also called "host parameter names" or "SQL parameters") 3865** can be set using the sqlite3_bind_*() routines defined here. 3866** 3867** ^The first argument to the sqlite3_bind_*() routines is always 3868** a pointer to the [sqlite3_stmt] object returned from 3869** [sqlite3_prepare_v2()] or its variants. 3870** 3871** ^The second argument is the index of the SQL parameter to be set. 3872** ^The leftmost SQL parameter has an index of 1. ^When the same named 3873** SQL parameter is used more than once, second and subsequent 3874** occurrences have the same index as the first occurrence. 3875** ^The index for named parameters can be looked up using the 3876** [sqlite3_bind_parameter_index()] API if desired. ^The index 3877** for "?NNN" parameters is the value of NNN. 3878** ^The NNN value must be between 1 and the [sqlite3_limit()] 3879** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3880** 3881** ^The third argument is the value to bind to the parameter. 3882** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3883** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3884** is ignored and the end result is the same as sqlite3_bind_null(). 3885** 3886** ^(In those routines that have a fourth argument, its value is the 3887** number of bytes in the parameter. To be clear: the value is the 3888** number of <u>bytes</u> in the value, not the number of characters.)^ 3889** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3890** is negative, then the length of the string is 3891** the number of bytes up to the first zero terminator. 3892** If the fourth parameter to sqlite3_bind_blob() is negative, then 3893** the behavior is undefined. 3894** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3895** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3896** that parameter must be the byte offset 3897** where the NUL terminator would occur assuming the string were NUL 3898** terminated. If any NUL characters occur at byte offsets less than 3899** the value of the fourth parameter then the resulting string value will 3900** contain embedded NULs. The result of expressions involving strings 3901** with embedded NULs is undefined. 3902** 3903** ^The fifth argument to the BLOB and string binding interfaces 3904** is a destructor used to dispose of the BLOB or 3905** string after SQLite has finished with it. ^The destructor is called 3906** to dispose of the BLOB or string even if the call to bind API fails. 3907** ^If the fifth argument is 3908** the special value [SQLITE_STATIC], then SQLite assumes that the 3909** information is in static, unmanaged space and does not need to be freed. 3910** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3911** SQLite makes its own private copy of the data immediately, before 3912** the sqlite3_bind_*() routine returns. 3913** 3914** ^The sixth argument to sqlite3_bind_text64() must be one of 3915** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3916** to specify the encoding of the text in the third parameter. If 3917** the sixth argument to sqlite3_bind_text64() is not one of the 3918** allowed values shown above, or if the text encoding is different 3919** from the encoding specified by the sixth parameter, then the behavior 3920** is undefined. 3921** 3922** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3923** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3924** (just an integer to hold its size) while it is being processed. 3925** Zeroblobs are intended to serve as placeholders for BLOBs whose 3926** content is later written using 3927** [sqlite3_blob_open | incremental BLOB I/O] routines. 3928** ^A negative value for the zeroblob results in a zero-length BLOB. 3929** 3930** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3931** [prepared statement] S to have an SQL value of NULL, but to also be 3932** associated with the pointer P of type T. ^D is either a NULL pointer or 3933** a pointer to a destructor function for P. ^SQLite will invoke the 3934** destructor D with a single argument of P when it is finished using 3935** P. The T parameter should be a static string, preferably a string 3936** literal. The sqlite3_bind_pointer() routine is part of the 3937** [pointer passing interface] added for SQLite 3.20.0. 3938** 3939** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3940** for the [prepared statement] or with a prepared statement for which 3941** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3942** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3943** routine is passed a [prepared statement] that has been finalized, the 3944** result is undefined and probably harmful. 3945** 3946** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3947** ^Unbound parameters are interpreted as NULL. 3948** 3949** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3950** [error code] if anything goes wrong. 3951** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3952** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3953** [SQLITE_MAX_LENGTH]. 3954** ^[SQLITE_RANGE] is returned if the parameter 3955** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3956** 3957** See also: [sqlite3_bind_parameter_count()], 3958** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3959*/ 3960int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3961int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3962 void(*)(void*)); 3963int sqlite3_bind_double(sqlite3_stmt*, int, double); 3964int sqlite3_bind_int(sqlite3_stmt*, int, int); 3965int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3966int sqlite3_bind_null(sqlite3_stmt*, int); 3967int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3968int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3969int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3970 void(*)(void*), unsigned char encoding); 3971int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3972int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3973int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3974int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3975 3976/* 3977** CAPI3REF: Number Of SQL Parameters 3978** METHOD: sqlite3_stmt 3979** 3980** ^This routine can be used to find the number of [SQL parameters] 3981** in a [prepared statement]. SQL parameters are tokens of the 3982** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3983** placeholders for values that are [sqlite3_bind_blob | bound] 3984** to the parameters at a later time. 3985** 3986** ^(This routine actually returns the index of the largest (rightmost) 3987** parameter. For all forms except ?NNN, this will correspond to the 3988** number of unique parameters. If parameters of the ?NNN form are used, 3989** there may be gaps in the list.)^ 3990** 3991** See also: [sqlite3_bind_blob|sqlite3_bind()], 3992** [sqlite3_bind_parameter_name()], and 3993** [sqlite3_bind_parameter_index()]. 3994*/ 3995int sqlite3_bind_parameter_count(sqlite3_stmt*); 3996 3997/* 3998** CAPI3REF: Name Of A Host Parameter 3999** METHOD: sqlite3_stmt 4000** 4001** ^The sqlite3_bind_parameter_name(P,N) interface returns 4002** the name of the N-th [SQL parameter] in the [prepared statement] P. 4003** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4004** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4005** respectively. 4006** In other words, the initial ":" or "$" or "@" or "?" 4007** is included as part of the name.)^ 4008** ^Parameters of the form "?" without a following integer have no name 4009** and are referred to as "nameless" or "anonymous parameters". 4010** 4011** ^The first host parameter has an index of 1, not 0. 4012** 4013** ^If the value N is out of range or if the N-th parameter is 4014** nameless, then NULL is returned. ^The returned string is 4015** always in UTF-8 encoding even if the named parameter was 4016** originally specified as UTF-16 in [sqlite3_prepare16()], 4017** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4018** 4019** See also: [sqlite3_bind_blob|sqlite3_bind()], 4020** [sqlite3_bind_parameter_count()], and 4021** [sqlite3_bind_parameter_index()]. 4022*/ 4023const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4024 4025/* 4026** CAPI3REF: Index Of A Parameter With A Given Name 4027** METHOD: sqlite3_stmt 4028** 4029** ^Return the index of an SQL parameter given its name. ^The 4030** index value returned is suitable for use as the second 4031** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4032** is returned if no matching parameter is found. ^The parameter 4033** name must be given in UTF-8 even if the original statement 4034** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4035** [sqlite3_prepare16_v3()]. 4036** 4037** See also: [sqlite3_bind_blob|sqlite3_bind()], 4038** [sqlite3_bind_parameter_count()], and 4039** [sqlite3_bind_parameter_name()]. 4040*/ 4041int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4042 4043/* 4044** CAPI3REF: Reset All Bindings On A Prepared Statement 4045** METHOD: sqlite3_stmt 4046** 4047** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4048** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4049** ^Use this routine to reset all host parameters to NULL. 4050*/ 4051int sqlite3_clear_bindings(sqlite3_stmt*); 4052 4053/* 4054** CAPI3REF: Number Of Columns In A Result Set 4055** METHOD: sqlite3_stmt 4056** 4057** ^Return the number of columns in the result set returned by the 4058** [prepared statement]. ^If this routine returns 0, that means the 4059** [prepared statement] returns no data (for example an [UPDATE]). 4060** ^However, just because this routine returns a positive number does not 4061** mean that one or more rows of data will be returned. ^A SELECT statement 4062** will always have a positive sqlite3_column_count() but depending on the 4063** WHERE clause constraints and the table content, it might return no rows. 4064** 4065** See also: [sqlite3_data_count()] 4066*/ 4067int sqlite3_column_count(sqlite3_stmt *pStmt); 4068 4069/* 4070** CAPI3REF: Column Names In A Result Set 4071** METHOD: sqlite3_stmt 4072** 4073** ^These routines return the name assigned to a particular column 4074** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4075** interface returns a pointer to a zero-terminated UTF-8 string 4076** and sqlite3_column_name16() returns a pointer to a zero-terminated 4077** UTF-16 string. ^The first parameter is the [prepared statement] 4078** that implements the [SELECT] statement. ^The second parameter is the 4079** column number. ^The leftmost column is number 0. 4080** 4081** ^The returned string pointer is valid until either the [prepared statement] 4082** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4083** reprepared by the first call to [sqlite3_step()] for a particular run 4084** or until the next call to 4085** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4086** 4087** ^If sqlite3_malloc() fails during the processing of either routine 4088** (for example during a conversion from UTF-8 to UTF-16) then a 4089** NULL pointer is returned. 4090** 4091** ^The name of a result column is the value of the "AS" clause for 4092** that column, if there is an AS clause. If there is no AS clause 4093** then the name of the column is unspecified and may change from 4094** one release of SQLite to the next. 4095*/ 4096const char *sqlite3_column_name(sqlite3_stmt*, int N); 4097const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4098 4099/* 4100** CAPI3REF: Source Of Data In A Query Result 4101** METHOD: sqlite3_stmt 4102** 4103** ^These routines provide a means to determine the database, table, and 4104** table column that is the origin of a particular result column in 4105** [SELECT] statement. 4106** ^The name of the database or table or column can be returned as 4107** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4108** the database name, the _table_ routines return the table name, and 4109** the origin_ routines return the column name. 4110** ^The returned string is valid until the [prepared statement] is destroyed 4111** using [sqlite3_finalize()] or until the statement is automatically 4112** reprepared by the first call to [sqlite3_step()] for a particular run 4113** or until the same information is requested 4114** again in a different encoding. 4115** 4116** ^The names returned are the original un-aliased names of the 4117** database, table, and column. 4118** 4119** ^The first argument to these interfaces is a [prepared statement]. 4120** ^These functions return information about the Nth result column returned by 4121** the statement, where N is the second function argument. 4122** ^The left-most column is column 0 for these routines. 4123** 4124** ^If the Nth column returned by the statement is an expression or 4125** subquery and is not a column value, then all of these functions return 4126** NULL. ^These routine might also return NULL if a memory allocation error 4127** occurs. ^Otherwise, they return the name of the attached database, table, 4128** or column that query result column was extracted from. 4129** 4130** ^As with all other SQLite APIs, those whose names end with "16" return 4131** UTF-16 encoded strings and the other functions return UTF-8. 4132** 4133** ^These APIs are only available if the library was compiled with the 4134** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4135** 4136** If two or more threads call one or more of these routines against the same 4137** prepared statement and column at the same time then the results are 4138** undefined. 4139** 4140** If two or more threads call one or more 4141** [sqlite3_column_database_name | column metadata interfaces] 4142** for the same [prepared statement] and result column 4143** at the same time then the results are undefined. 4144*/ 4145const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4146const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4147const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4148const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4149const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4150const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4151 4152/* 4153** CAPI3REF: Declared Datatype Of A Query Result 4154** METHOD: sqlite3_stmt 4155** 4156** ^(The first parameter is a [prepared statement]. 4157** If this statement is a [SELECT] statement and the Nth column of the 4158** returned result set of that [SELECT] is a table column (not an 4159** expression or subquery) then the declared type of the table 4160** column is returned.)^ ^If the Nth column of the result set is an 4161** expression or subquery, then a NULL pointer is returned. 4162** ^The returned string is always UTF-8 encoded. 4163** 4164** ^(For example, given the database schema: 4165** 4166** CREATE TABLE t1(c1 VARIANT); 4167** 4168** and the following statement to be compiled: 4169** 4170** SELECT c1 + 1, c1 FROM t1; 4171** 4172** this routine would return the string "VARIANT" for the second result 4173** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4174** 4175** ^SQLite uses dynamic run-time typing. ^So just because a column 4176** is declared to contain a particular type does not mean that the 4177** data stored in that column is of the declared type. SQLite is 4178** strongly typed, but the typing is dynamic not static. ^Type 4179** is associated with individual values, not with the containers 4180** used to hold those values. 4181*/ 4182const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4183const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4184 4185/* 4186** CAPI3REF: Evaluate An SQL Statement 4187** METHOD: sqlite3_stmt 4188** 4189** After a [prepared statement] has been prepared using any of 4190** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4191** or [sqlite3_prepare16_v3()] or one of the legacy 4192** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4193** must be called one or more times to evaluate the statement. 4194** 4195** The details of the behavior of the sqlite3_step() interface depend 4196** on whether the statement was prepared using the newer "vX" interfaces 4197** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4198** [sqlite3_prepare16_v2()] or the older legacy 4199** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4200** new "vX" interface is recommended for new applications but the legacy 4201** interface will continue to be supported. 4202** 4203** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4204** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4205** ^With the "v2" interface, any of the other [result codes] or 4206** [extended result codes] might be returned as well. 4207** 4208** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4209** database locks it needs to do its job. ^If the statement is a [COMMIT] 4210** or occurs outside of an explicit transaction, then you can retry the 4211** statement. If the statement is not a [COMMIT] and occurs within an 4212** explicit transaction then you should rollback the transaction before 4213** continuing. 4214** 4215** ^[SQLITE_DONE] means that the statement has finished executing 4216** successfully. sqlite3_step() should not be called again on this virtual 4217** machine without first calling [sqlite3_reset()] to reset the virtual 4218** machine back to its initial state. 4219** 4220** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4221** is returned each time a new row of data is ready for processing by the 4222** caller. The values may be accessed using the [column access functions]. 4223** sqlite3_step() is called again to retrieve the next row of data. 4224** 4225** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4226** violation) has occurred. sqlite3_step() should not be called again on 4227** the VM. More information may be found by calling [sqlite3_errmsg()]. 4228** ^With the legacy interface, a more specific error code (for example, 4229** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4230** can be obtained by calling [sqlite3_reset()] on the 4231** [prepared statement]. ^In the "v2" interface, 4232** the more specific error code is returned directly by sqlite3_step(). 4233** 4234** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4235** Perhaps it was called on a [prepared statement] that has 4236** already been [sqlite3_finalize | finalized] or on one that had 4237** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4238** be the case that the same database connection is being used by two or 4239** more threads at the same moment in time. 4240** 4241** For all versions of SQLite up to and including 3.6.23.1, a call to 4242** [sqlite3_reset()] was required after sqlite3_step() returned anything 4243** other than [SQLITE_ROW] before any subsequent invocation of 4244** sqlite3_step(). Failure to reset the prepared statement using 4245** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4246** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4247** sqlite3_step() began 4248** calling [sqlite3_reset()] automatically in this circumstance rather 4249** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4250** break because any application that ever receives an SQLITE_MISUSE error 4251** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4252** can be used to restore the legacy behavior. 4253** 4254** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4255** API always returns a generic error code, [SQLITE_ERROR], following any 4256** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4257** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4258** specific [error codes] that better describes the error. 4259** We admit that this is a goofy design. The problem has been fixed 4260** with the "v2" interface. If you prepare all of your SQL statements 4261** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4262** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4263** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4264** then the more specific [error codes] are returned directly 4265** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4266*/ 4267int sqlite3_step(sqlite3_stmt*); 4268 4269/* 4270** CAPI3REF: Number of columns in a result set 4271** METHOD: sqlite3_stmt 4272** 4273** ^The sqlite3_data_count(P) interface returns the number of columns in the 4274** current row of the result set of [prepared statement] P. 4275** ^If prepared statement P does not have results ready to return 4276** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4277** interfaces) then sqlite3_data_count(P) returns 0. 4278** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4279** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4280** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4281** will return non-zero if previous call to [sqlite3_step](P) returned 4282** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4283** where it always returns zero since each step of that multi-step 4284** pragma returns 0 columns of data. 4285** 4286** See also: [sqlite3_column_count()] 4287*/ 4288int sqlite3_data_count(sqlite3_stmt *pStmt); 4289 4290/* 4291** CAPI3REF: Fundamental Datatypes 4292** KEYWORDS: SQLITE_TEXT 4293** 4294** ^(Every value in SQLite has one of five fundamental datatypes: 4295** 4296** <ul> 4297** <li> 64-bit signed integer 4298** <li> 64-bit IEEE floating point number 4299** <li> string 4300** <li> BLOB 4301** <li> NULL 4302** </ul>)^ 4303** 4304** These constants are codes for each of those types. 4305** 4306** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4307** for a completely different meaning. Software that links against both 4308** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4309** SQLITE_TEXT. 4310*/ 4311#define SQLITE_INTEGER 1 4312#define SQLITE_FLOAT 2 4313#define SQLITE_BLOB 4 4314#define SQLITE_NULL 5 4315#ifdef SQLITE_TEXT 4316# undef SQLITE_TEXT 4317#else 4318# define SQLITE_TEXT 3 4319#endif 4320#define SQLITE3_TEXT 3 4321 4322/* 4323** CAPI3REF: Result Values From A Query 4324** KEYWORDS: {column access functions} 4325** METHOD: sqlite3_stmt 4326** 4327** <b>Summary:</b> 4328** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4329** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4330** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4331** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4332** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4333** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4334** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4335** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4336** [sqlite3_value|unprotected sqlite3_value] object. 4337** <tr><td> <td> <td> 4338** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4339** or a UTF-8 TEXT result in bytes 4340** <tr><td><b>sqlite3_column_bytes16 </b> 4341** <td>→ <td>Size of UTF-16 4342** TEXT in bytes 4343** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4344** datatype of the result 4345** </table></blockquote> 4346** 4347** <b>Details:</b> 4348** 4349** ^These routines return information about a single column of the current 4350** result row of a query. ^In every case the first argument is a pointer 4351** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4352** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4353** and the second argument is the index of the column for which information 4354** should be returned. ^The leftmost column of the result set has the index 0. 4355** ^The number of columns in the result can be determined using 4356** [sqlite3_column_count()]. 4357** 4358** If the SQL statement does not currently point to a valid row, or if the 4359** column index is out of range, the result is undefined. 4360** These routines may only be called when the most recent call to 4361** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4362** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4363** If any of these routines are called after [sqlite3_reset()] or 4364** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4365** something other than [SQLITE_ROW], the results are undefined. 4366** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4367** are called from a different thread while any of these routines 4368** are pending, then the results are undefined. 4369** 4370** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4371** each return the value of a result column in a specific data format. If 4372** the result column is not initially in the requested format (for example, 4373** if the query returns an integer but the sqlite3_column_text() interface 4374** is used to extract the value) then an automatic type conversion is performed. 4375** 4376** ^The sqlite3_column_type() routine returns the 4377** [SQLITE_INTEGER | datatype code] for the initial data type 4378** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4379** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4380** The return value of sqlite3_column_type() can be used to decide which 4381** of the first six interface should be used to extract the column value. 4382** The value returned by sqlite3_column_type() is only meaningful if no 4383** automatic type conversions have occurred for the value in question. 4384** After a type conversion, the result of calling sqlite3_column_type() 4385** is undefined, though harmless. Future 4386** versions of SQLite may change the behavior of sqlite3_column_type() 4387** following a type conversion. 4388** 4389** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4390** or sqlite3_column_bytes16() interfaces can be used to determine the size 4391** of that BLOB or string. 4392** 4393** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4394** routine returns the number of bytes in that BLOB or string. 4395** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4396** the string to UTF-8 and then returns the number of bytes. 4397** ^If the result is a numeric value then sqlite3_column_bytes() uses 4398** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4399** the number of bytes in that string. 4400** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4401** 4402** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4403** routine returns the number of bytes in that BLOB or string. 4404** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4405** the string to UTF-16 and then returns the number of bytes. 4406** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4407** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4408** the number of bytes in that string. 4409** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4410** 4411** ^The values returned by [sqlite3_column_bytes()] and 4412** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4413** of the string. ^For clarity: the values returned by 4414** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4415** bytes in the string, not the number of characters. 4416** 4417** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4418** even empty strings, are always zero-terminated. ^The return 4419** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4420** 4421** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4422** [unprotected sqlite3_value] object. In a multithreaded environment, 4423** an unprotected sqlite3_value object may only be used safely with 4424** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4425** If the [unprotected sqlite3_value] object returned by 4426** [sqlite3_column_value()] is used in any other way, including calls 4427** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4428** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4429** Hence, the sqlite3_column_value() interface 4430** is normally only useful within the implementation of 4431** [application-defined SQL functions] or [virtual tables], not within 4432** top-level application code. 4433** 4434** The these routines may attempt to convert the datatype of the result. 4435** ^For example, if the internal representation is FLOAT and a text result 4436** is requested, [sqlite3_snprintf()] is used internally to perform the 4437** conversion automatically. ^(The following table details the conversions 4438** that are applied: 4439** 4440** <blockquote> 4441** <table border="1"> 4442** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4443** 4444** <tr><td> NULL <td> INTEGER <td> Result is 0 4445** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4446** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4447** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4448** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4449** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4450** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4451** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4452** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4453** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4454** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4455** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4456** <tr><td> TEXT <td> BLOB <td> No change 4457** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4458** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4459** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4460** </table> 4461** </blockquote>)^ 4462** 4463** Note that when type conversions occur, pointers returned by prior 4464** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4465** sqlite3_column_text16() may be invalidated. 4466** Type conversions and pointer invalidations might occur 4467** in the following cases: 4468** 4469** <ul> 4470** <li> The initial content is a BLOB and sqlite3_column_text() or 4471** sqlite3_column_text16() is called. A zero-terminator might 4472** need to be added to the string.</li> 4473** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4474** sqlite3_column_text16() is called. The content must be converted 4475** to UTF-16.</li> 4476** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4477** sqlite3_column_text() is called. The content must be converted 4478** to UTF-8.</li> 4479** </ul> 4480** 4481** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4482** not invalidate a prior pointer, though of course the content of the buffer 4483** that the prior pointer references will have been modified. Other kinds 4484** of conversion are done in place when it is possible, but sometimes they 4485** are not possible and in those cases prior pointers are invalidated. 4486** 4487** The safest policy is to invoke these routines 4488** in one of the following ways: 4489** 4490** <ul> 4491** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4492** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4493** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4494** </ul> 4495** 4496** In other words, you should call sqlite3_column_text(), 4497** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4498** into the desired format, then invoke sqlite3_column_bytes() or 4499** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4500** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4501** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4502** with calls to sqlite3_column_bytes(). 4503** 4504** ^The pointers returned are valid until a type conversion occurs as 4505** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4506** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4507** and BLOBs is freed automatically. Do not pass the pointers returned 4508** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4509** [sqlite3_free()]. 4510** 4511** ^(If a memory allocation error occurs during the evaluation of any 4512** of these routines, a default value is returned. The default value 4513** is either the integer 0, the floating point number 0.0, or a NULL 4514** pointer. Subsequent calls to [sqlite3_errcode()] will return 4515** [SQLITE_NOMEM].)^ 4516*/ 4517const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4518double sqlite3_column_double(sqlite3_stmt*, int iCol); 4519int sqlite3_column_int(sqlite3_stmt*, int iCol); 4520sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4521const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4522const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4523sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4524int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4525int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4526int sqlite3_column_type(sqlite3_stmt*, int iCol); 4527 4528/* 4529** CAPI3REF: Destroy A Prepared Statement Object 4530** DESTRUCTOR: sqlite3_stmt 4531** 4532** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4533** ^If the most recent evaluation of the statement encountered no errors 4534** or if the statement is never been evaluated, then sqlite3_finalize() returns 4535** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4536** sqlite3_finalize(S) returns the appropriate [error code] or 4537** [extended error code]. 4538** 4539** ^The sqlite3_finalize(S) routine can be called at any point during 4540** the life cycle of [prepared statement] S: 4541** before statement S is ever evaluated, after 4542** one or more calls to [sqlite3_reset()], or after any call 4543** to [sqlite3_step()] regardless of whether or not the statement has 4544** completed execution. 4545** 4546** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4547** 4548** The application must finalize every [prepared statement] in order to avoid 4549** resource leaks. It is a grievous error for the application to try to use 4550** a prepared statement after it has been finalized. Any use of a prepared 4551** statement after it has been finalized can result in undefined and 4552** undesirable behavior such as segfaults and heap corruption. 4553*/ 4554int sqlite3_finalize(sqlite3_stmt *pStmt); 4555 4556/* 4557** CAPI3REF: Reset A Prepared Statement Object 4558** METHOD: sqlite3_stmt 4559** 4560** The sqlite3_reset() function is called to reset a [prepared statement] 4561** object back to its initial state, ready to be re-executed. 4562** ^Any SQL statement variables that had values bound to them using 4563** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4564** Use [sqlite3_clear_bindings()] to reset the bindings. 4565** 4566** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4567** back to the beginning of its program. 4568** 4569** ^If the most recent call to [sqlite3_step(S)] for the 4570** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4571** or if [sqlite3_step(S)] has never before been called on S, 4572** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4573** 4574** ^If the most recent call to [sqlite3_step(S)] for the 4575** [prepared statement] S indicated an error, then 4576** [sqlite3_reset(S)] returns an appropriate [error code]. 4577** 4578** ^The [sqlite3_reset(S)] interface does not change the values 4579** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4580*/ 4581int sqlite3_reset(sqlite3_stmt *pStmt); 4582 4583/* 4584** CAPI3REF: Create Or Redefine SQL Functions 4585** KEYWORDS: {function creation routines} 4586** KEYWORDS: {application-defined SQL function} 4587** KEYWORDS: {application-defined SQL functions} 4588** METHOD: sqlite3 4589** 4590** ^These functions (collectively known as "function creation routines") 4591** are used to add SQL functions or aggregates or to redefine the behavior 4592** of existing SQL functions or aggregates. The only differences between 4593** these routines are the text encoding expected for 4594** the second parameter (the name of the function being created) 4595** and the presence or absence of a destructor callback for 4596** the application data pointer. 4597** 4598** ^The first parameter is the [database connection] to which the SQL 4599** function is to be added. ^If an application uses more than one database 4600** connection then application-defined SQL functions must be added 4601** to each database connection separately. 4602** 4603** ^The second parameter is the name of the SQL function to be created or 4604** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4605** representation, exclusive of the zero-terminator. ^Note that the name 4606** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4607** ^Any attempt to create a function with a longer name 4608** will result in [SQLITE_MISUSE] being returned. 4609** 4610** ^The third parameter (nArg) 4611** is the number of arguments that the SQL function or 4612** aggregate takes. ^If this parameter is -1, then the SQL function or 4613** aggregate may take any number of arguments between 0 and the limit 4614** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4615** parameter is less than -1 or greater than 127 then the behavior is 4616** undefined. 4617** 4618** ^The fourth parameter, eTextRep, specifies what 4619** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4620** its parameters. The application should set this parameter to 4621** [SQLITE_UTF16LE] if the function implementation invokes 4622** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4623** implementation invokes [sqlite3_value_text16be()] on an input, or 4624** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4625** otherwise. ^The same SQL function may be registered multiple times using 4626** different preferred text encodings, with different implementations for 4627** each encoding. 4628** ^When multiple implementations of the same function are available, SQLite 4629** will pick the one that involves the least amount of data conversion. 4630** 4631** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4632** to signal that the function will always return the same result given 4633** the same inputs within a single SQL statement. Most SQL functions are 4634** deterministic. The built-in [random()] SQL function is an example of a 4635** function that is not deterministic. The SQLite query planner is able to 4636** perform additional optimizations on deterministic functions, so use 4637** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4638** 4639** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4640** function can gain access to this pointer using [sqlite3_user_data()].)^ 4641** 4642** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4643** pointers to C-language functions that implement the SQL function or 4644** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4645** callback only; NULL pointers must be passed as the xStep and xFinal 4646** parameters. ^An aggregate SQL function requires an implementation of xStep 4647** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4648** SQL function or aggregate, pass NULL pointers for all three function 4649** callbacks. 4650** 4651** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4652** then it is destructor for the application data pointer. 4653** The destructor is invoked when the function is deleted, either by being 4654** overloaded or when the database connection closes.)^ 4655** ^The destructor is also invoked if the call to 4656** sqlite3_create_function_v2() fails. 4657** ^When the destructor callback of the tenth parameter is invoked, it 4658** is passed a single argument which is a copy of the application data 4659** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4660** 4661** ^It is permitted to register multiple implementations of the same 4662** functions with the same name but with either differing numbers of 4663** arguments or differing preferred text encodings. ^SQLite will use 4664** the implementation that most closely matches the way in which the 4665** SQL function is used. ^A function implementation with a non-negative 4666** nArg parameter is a better match than a function implementation with 4667** a negative nArg. ^A function where the preferred text encoding 4668** matches the database encoding is a better 4669** match than a function where the encoding is different. 4670** ^A function where the encoding difference is between UTF16le and UTF16be 4671** is a closer match than a function where the encoding difference is 4672** between UTF8 and UTF16. 4673** 4674** ^Built-in functions may be overloaded by new application-defined functions. 4675** 4676** ^An application-defined function is permitted to call other 4677** SQLite interfaces. However, such calls must not 4678** close the database connection nor finalize or reset the prepared 4679** statement in which the function is running. 4680*/ 4681int sqlite3_create_function( 4682 sqlite3 *db, 4683 const char *zFunctionName, 4684 int nArg, 4685 int eTextRep, 4686 void *pApp, 4687 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4688 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4689 void (*xFinal)(sqlite3_context*) 4690); 4691int sqlite3_create_function16( 4692 sqlite3 *db, 4693 const void *zFunctionName, 4694 int nArg, 4695 int eTextRep, 4696 void *pApp, 4697 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4698 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4699 void (*xFinal)(sqlite3_context*) 4700); 4701int sqlite3_create_function_v2( 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 void(*xDestroy)(void*) 4711); 4712 4713/* 4714** CAPI3REF: Text Encodings 4715** 4716** These constant define integer codes that represent the various 4717** text encodings supported by SQLite. 4718*/ 4719#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4720#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4721#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4722#define SQLITE_UTF16 4 /* Use native byte order */ 4723#define SQLITE_ANY 5 /* Deprecated */ 4724#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4725 4726/* 4727** CAPI3REF: Function Flags 4728** 4729** These constants may be ORed together with the 4730** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4731** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4732** [sqlite3_create_function_v2()]. 4733*/ 4734#define SQLITE_DETERMINISTIC 0x800 4735 4736/* 4737** CAPI3REF: Deprecated Functions 4738** DEPRECATED 4739** 4740** These functions are [deprecated]. In order to maintain 4741** backwards compatibility with older code, these functions continue 4742** to be supported. However, new applications should avoid 4743** the use of these functions. To encourage programmers to avoid 4744** these functions, we will not explain what they do. 4745*/ 4746#ifndef SQLITE_OMIT_DEPRECATED 4747SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4748SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4749SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4750SQLITE_DEPRECATED int sqlite3_global_recover(void); 4751SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4752SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4753 void*,sqlite3_int64); 4754#endif 4755 4756/* 4757** CAPI3REF: Obtaining SQL Values 4758** METHOD: sqlite3_value 4759** 4760** <b>Summary:</b> 4761** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4762** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4763** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4764** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4765** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4766** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4767** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4768** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4769** the native byteorder 4770** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4771** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4772** <tr><td> <td> <td> 4773** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4774** or a UTF-8 TEXT in bytes 4775** <tr><td><b>sqlite3_value_bytes16 </b> 4776** <td>→ <td>Size of UTF-16 4777** TEXT in bytes 4778** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4779** datatype of the value 4780** <tr><td><b>sqlite3_value_numeric_type </b> 4781** <td>→ <td>Best numeric datatype of the value 4782** </table></blockquote> 4783** 4784** <b>Details:</b> 4785** 4786** These routines extract type, size, and content information from 4787** [protected sqlite3_value] objects. Protected sqlite3_value objects 4788** are used to pass parameter information into implementation of 4789** [application-defined SQL functions] and [virtual tables]. 4790** 4791** These routines work only with [protected sqlite3_value] objects. 4792** Any attempt to use these routines on an [unprotected sqlite3_value] 4793** is not threadsafe. 4794** 4795** ^These routines work just like the corresponding [column access functions] 4796** except that these routines take a single [protected sqlite3_value] object 4797** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4798** 4799** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4800** in the native byte-order of the host machine. ^The 4801** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4802** extract UTF-16 strings as big-endian and little-endian respectively. 4803** 4804** ^If [sqlite3_value] object V was initialized 4805** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4806** and if X and Y are strings that compare equal according to strcmp(X,Y), 4807** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4808** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4809** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4810** 4811** ^(The sqlite3_value_type(V) interface returns the 4812** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4813** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4814** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4815** Other interfaces might change the datatype for an sqlite3_value object. 4816** For example, if the datatype is initially SQLITE_INTEGER and 4817** sqlite3_value_text(V) is called to extract a text value for that 4818** integer, then subsequent calls to sqlite3_value_type(V) might return 4819** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4820** occurs is undefined and may change from one release of SQLite to the next. 4821** 4822** ^(The sqlite3_value_numeric_type() interface attempts to apply 4823** numeric affinity to the value. This means that an attempt is 4824** made to convert the value to an integer or floating point. If 4825** such a conversion is possible without loss of information (in other 4826** words, if the value is a string that looks like a number) 4827** then the conversion is performed. Otherwise no conversion occurs. 4828** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4829** 4830** Please pay particular attention to the fact that the pointer returned 4831** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4832** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4833** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4834** or [sqlite3_value_text16()]. 4835** 4836** These routines must be called from the same thread as 4837** the SQL function that supplied the [sqlite3_value*] parameters. 4838*/ 4839const void *sqlite3_value_blob(sqlite3_value*); 4840double sqlite3_value_double(sqlite3_value*); 4841int sqlite3_value_int(sqlite3_value*); 4842sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4843void *sqlite3_value_pointer(sqlite3_value*, const char*); 4844const unsigned char *sqlite3_value_text(sqlite3_value*); 4845const void *sqlite3_value_text16(sqlite3_value*); 4846const void *sqlite3_value_text16le(sqlite3_value*); 4847const void *sqlite3_value_text16be(sqlite3_value*); 4848int sqlite3_value_bytes(sqlite3_value*); 4849int sqlite3_value_bytes16(sqlite3_value*); 4850int sqlite3_value_type(sqlite3_value*); 4851int sqlite3_value_numeric_type(sqlite3_value*); 4852 4853/* 4854** CAPI3REF: Finding The Subtype Of SQL Values 4855** METHOD: sqlite3_value 4856** 4857** The sqlite3_value_subtype(V) function returns the subtype for 4858** an [application-defined SQL function] argument V. The subtype 4859** information can be used to pass a limited amount of context from 4860** one SQL function to another. Use the [sqlite3_result_subtype()] 4861** routine to set the subtype for the return value of an SQL function. 4862*/ 4863unsigned int sqlite3_value_subtype(sqlite3_value*); 4864 4865/* 4866** CAPI3REF: Copy And Free SQL Values 4867** METHOD: sqlite3_value 4868** 4869** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4870** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4871** is a [protected sqlite3_value] object even if the input is not. 4872** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4873** memory allocation fails. 4874** 4875** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4876** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4877** then sqlite3_value_free(V) is a harmless no-op. 4878*/ 4879sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4880void sqlite3_value_free(sqlite3_value*); 4881 4882/* 4883** CAPI3REF: Obtain Aggregate Function Context 4884** METHOD: sqlite3_context 4885** 4886** Implementations of aggregate SQL functions use this 4887** routine to allocate memory for storing their state. 4888** 4889** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4890** for a particular aggregate function, SQLite 4891** allocates N of memory, zeroes out that memory, and returns a pointer 4892** to the new memory. ^On second and subsequent calls to 4893** sqlite3_aggregate_context() for the same aggregate function instance, 4894** the same buffer is returned. Sqlite3_aggregate_context() is normally 4895** called once for each invocation of the xStep callback and then one 4896** last time when the xFinal callback is invoked. ^(When no rows match 4897** an aggregate query, the xStep() callback of the aggregate function 4898** implementation is never called and xFinal() is called exactly once. 4899** In those cases, sqlite3_aggregate_context() might be called for the 4900** first time from within xFinal().)^ 4901** 4902** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4903** when first called if N is less than or equal to zero or if a memory 4904** allocate error occurs. 4905** 4906** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4907** determined by the N parameter on first successful call. Changing the 4908** value of N in subsequent call to sqlite3_aggregate_context() within 4909** the same aggregate function instance will not resize the memory 4910** allocation.)^ Within the xFinal callback, it is customary to set 4911** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4912** pointless memory allocations occur. 4913** 4914** ^SQLite automatically frees the memory allocated by 4915** sqlite3_aggregate_context() when the aggregate query concludes. 4916** 4917** The first parameter must be a copy of the 4918** [sqlite3_context | SQL function context] that is the first parameter 4919** to the xStep or xFinal callback routine that implements the aggregate 4920** function. 4921** 4922** This routine must be called from the same thread in which 4923** the aggregate SQL function is running. 4924*/ 4925void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4926 4927/* 4928** CAPI3REF: User Data For Functions 4929** METHOD: sqlite3_context 4930** 4931** ^The sqlite3_user_data() interface returns a copy of 4932** the pointer that was the pUserData parameter (the 5th parameter) 4933** of the [sqlite3_create_function()] 4934** and [sqlite3_create_function16()] routines that originally 4935** registered the application defined function. 4936** 4937** This routine must be called from the same thread in which 4938** the application-defined function is running. 4939*/ 4940void *sqlite3_user_data(sqlite3_context*); 4941 4942/* 4943** CAPI3REF: Database Connection For Functions 4944** METHOD: sqlite3_context 4945** 4946** ^The sqlite3_context_db_handle() interface returns a copy of 4947** the pointer to the [database connection] (the 1st parameter) 4948** of the [sqlite3_create_function()] 4949** and [sqlite3_create_function16()] routines that originally 4950** registered the application defined function. 4951*/ 4952sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4953 4954/* 4955** CAPI3REF: Function Auxiliary Data 4956** METHOD: sqlite3_context 4957** 4958** These functions may be used by (non-aggregate) SQL functions to 4959** associate metadata with argument values. If the same value is passed to 4960** multiple invocations of the same SQL function during query execution, under 4961** some circumstances the associated metadata may be preserved. An example 4962** of where this might be useful is in a regular-expression matching 4963** function. The compiled version of the regular expression can be stored as 4964** metadata associated with the pattern string. 4965** Then as long as the pattern string remains the same, 4966** the compiled regular expression can be reused on multiple 4967** invocations of the same function. 4968** 4969** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4970** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4971** value to the application-defined function. ^N is zero for the left-most 4972** function argument. ^If there is no metadata 4973** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4974** returns a NULL pointer. 4975** 4976** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4977** argument of the application-defined function. ^Subsequent 4978** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4979** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4980** NULL if the metadata has been discarded. 4981** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4982** SQLite will invoke the destructor function X with parameter P exactly 4983** once, when the metadata is discarded. 4984** SQLite is free to discard the metadata at any time, including: <ul> 4985** <li> ^(when the corresponding function parameter changes)^, or 4986** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4987** SQL statement)^, or 4988** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4989** parameter)^, or 4990** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4991** allocation error occurs.)^ </ul> 4992** 4993** Note the last bullet in particular. The destructor X in 4994** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4995** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4996** should be called near the end of the function implementation and the 4997** function implementation should not make any use of P after 4998** sqlite3_set_auxdata() has been called. 4999** 5000** ^(In practice, metadata is preserved between function calls for 5001** function parameters that are compile-time constants, including literal 5002** values and [parameters] and expressions composed from the same.)^ 5003** 5004** The value of the N parameter to these interfaces should be non-negative. 5005** Future enhancements may make use of negative N values to define new 5006** kinds of function caching behavior. 5007** 5008** These routines must be called from the same thread in which 5009** the SQL function is running. 5010*/ 5011void *sqlite3_get_auxdata(sqlite3_context*, int N); 5012void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5013 5014 5015/* 5016** CAPI3REF: Constants Defining Special Destructor Behavior 5017** 5018** These are special values for the destructor that is passed in as the 5019** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5020** argument is SQLITE_STATIC, it means that the content pointer is constant 5021** and will never change. It does not need to be destroyed. ^The 5022** SQLITE_TRANSIENT value means that the content will likely change in 5023** the near future and that SQLite should make its own private copy of 5024** the content before returning. 5025** 5026** The typedef is necessary to work around problems in certain 5027** C++ compilers. 5028*/ 5029typedef void (*sqlite3_destructor_type)(void*); 5030#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5031#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5032 5033/* 5034** CAPI3REF: Setting The Result Of An SQL Function 5035** METHOD: sqlite3_context 5036** 5037** These routines are used by the xFunc or xFinal callbacks that 5038** implement SQL functions and aggregates. See 5039** [sqlite3_create_function()] and [sqlite3_create_function16()] 5040** for additional information. 5041** 5042** These functions work very much like the [parameter binding] family of 5043** functions used to bind values to host parameters in prepared statements. 5044** Refer to the [SQL parameter] documentation for additional information. 5045** 5046** ^The sqlite3_result_blob() interface sets the result from 5047** an application-defined function to be the BLOB whose content is pointed 5048** to by the second parameter and which is N bytes long where N is the 5049** third parameter. 5050** 5051** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5052** interfaces set the result of the application-defined function to be 5053** a BLOB containing all zero bytes and N bytes in size. 5054** 5055** ^The sqlite3_result_double() interface sets the result from 5056** an application-defined function to be a floating point value specified 5057** by its 2nd argument. 5058** 5059** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5060** cause the implemented SQL function to throw an exception. 5061** ^SQLite uses the string pointed to by the 5062** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5063** as the text of an error message. ^SQLite interprets the error 5064** message string from sqlite3_result_error() as UTF-8. ^SQLite 5065** interprets the string from sqlite3_result_error16() as UTF-16 in native 5066** byte order. ^If the third parameter to sqlite3_result_error() 5067** or sqlite3_result_error16() is negative then SQLite takes as the error 5068** message all text up through the first zero character. 5069** ^If the third parameter to sqlite3_result_error() or 5070** sqlite3_result_error16() is non-negative then SQLite takes that many 5071** bytes (not characters) from the 2nd parameter as the error message. 5072** ^The sqlite3_result_error() and sqlite3_result_error16() 5073** routines make a private copy of the error message text before 5074** they return. Hence, the calling function can deallocate or 5075** modify the text after they return without harm. 5076** ^The sqlite3_result_error_code() function changes the error code 5077** returned by SQLite as a result of an error in a function. ^By default, 5078** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5079** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5080** 5081** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5082** error indicating that a string or BLOB is too long to represent. 5083** 5084** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5085** error indicating that a memory allocation failed. 5086** 5087** ^The sqlite3_result_int() interface sets the return value 5088** of the application-defined function to be the 32-bit signed integer 5089** value given in the 2nd argument. 5090** ^The sqlite3_result_int64() interface sets the return value 5091** of the application-defined function to be the 64-bit signed integer 5092** value given in the 2nd argument. 5093** 5094** ^The sqlite3_result_null() interface sets the return value 5095** of the application-defined function to be NULL. 5096** 5097** ^The sqlite3_result_text(), sqlite3_result_text16(), 5098** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5099** set the return value of the application-defined function to be 5100** a text string which is represented as UTF-8, UTF-16 native byte order, 5101** UTF-16 little endian, or UTF-16 big endian, respectively. 5102** ^The sqlite3_result_text64() interface sets the return value of an 5103** application-defined function to be a text string in an encoding 5104** specified by the fifth (and last) parameter, which must be one 5105** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5106** ^SQLite takes the text result from the application from 5107** the 2nd parameter of the sqlite3_result_text* interfaces. 5108** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5109** is negative, then SQLite takes result text from the 2nd parameter 5110** through the first zero character. 5111** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5112** is non-negative, then as many bytes (not characters) of the text 5113** pointed to by the 2nd parameter are taken as the application-defined 5114** function result. If the 3rd parameter is non-negative, then it 5115** must be the byte offset into the string where the NUL terminator would 5116** appear if the string where NUL terminated. If any NUL characters occur 5117** in the string at a byte offset that is less than the value of the 3rd 5118** parameter, then the resulting string will contain embedded NULs and the 5119** result of expressions operating on strings with embedded NULs is undefined. 5120** ^If the 4th parameter to the sqlite3_result_text* interfaces 5121** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5122** function as the destructor on the text or BLOB result when it has 5123** finished using that result. 5124** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5125** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5126** assumes that the text or BLOB result is in constant space and does not 5127** copy the content of the parameter nor call a destructor on the content 5128** when it has finished using that result. 5129** ^If the 4th parameter to the sqlite3_result_text* interfaces 5130** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5131** then SQLite makes a copy of the result into space obtained 5132** from [sqlite3_malloc()] before it returns. 5133** 5134** ^The sqlite3_result_value() interface sets the result of 5135** the application-defined function to be a copy of the 5136** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5137** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5138** so that the [sqlite3_value] specified in the parameter may change or 5139** be deallocated after sqlite3_result_value() returns without harm. 5140** ^A [protected sqlite3_value] object may always be used where an 5141** [unprotected sqlite3_value] object is required, so either 5142** kind of [sqlite3_value] object can be used with this interface. 5143** 5144** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5145** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5146** also associates the host-language pointer P or type T with that 5147** NULL value such that the pointer can be retrieved within an 5148** [application-defined SQL function] using [sqlite3_value_pointer()]. 5149** ^If the D parameter is not NULL, then it is a pointer to a destructor 5150** for the P parameter. ^SQLite invokes D with P as its only argument 5151** when SQLite is finished with P. The T parameter should be a static 5152** string and preferably a string literal. The sqlite3_result_pointer() 5153** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5154** 5155** If these routines are called from within the different thread 5156** than the one containing the application-defined function that received 5157** the [sqlite3_context] pointer, the results are undefined. 5158*/ 5159void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5160void sqlite3_result_blob64(sqlite3_context*,const void*, 5161 sqlite3_uint64,void(*)(void*)); 5162void sqlite3_result_double(sqlite3_context*, double); 5163void sqlite3_result_error(sqlite3_context*, const char*, int); 5164void sqlite3_result_error16(sqlite3_context*, const void*, int); 5165void sqlite3_result_error_toobig(sqlite3_context*); 5166void sqlite3_result_error_nomem(sqlite3_context*); 5167void sqlite3_result_error_code(sqlite3_context*, int); 5168void sqlite3_result_int(sqlite3_context*, int); 5169void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5170void sqlite3_result_null(sqlite3_context*); 5171void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5172void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5173 void(*)(void*), unsigned char encoding); 5174void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5175void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5176void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5177void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5178void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5179void sqlite3_result_zeroblob(sqlite3_context*, int n); 5180int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5181 5182 5183/* 5184** CAPI3REF: Setting The Subtype Of An SQL Function 5185** METHOD: sqlite3_context 5186** 5187** The sqlite3_result_subtype(C,T) function causes the subtype of 5188** the result from the [application-defined SQL function] with 5189** [sqlite3_context] C to be the value T. Only the lower 8 bits 5190** of the subtype T are preserved in current versions of SQLite; 5191** higher order bits are discarded. 5192** The number of subtype bytes preserved by SQLite might increase 5193** in future releases of SQLite. 5194*/ 5195void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5196 5197/* 5198** CAPI3REF: Define New Collating Sequences 5199** METHOD: sqlite3 5200** 5201** ^These functions add, remove, or modify a [collation] associated 5202** with the [database connection] specified as the first argument. 5203** 5204** ^The name of the collation is a UTF-8 string 5205** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5206** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5207** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5208** considered to be the same name. 5209** 5210** ^(The third argument (eTextRep) must be one of the constants: 5211** <ul> 5212** <li> [SQLITE_UTF8], 5213** <li> [SQLITE_UTF16LE], 5214** <li> [SQLITE_UTF16BE], 5215** <li> [SQLITE_UTF16], or 5216** <li> [SQLITE_UTF16_ALIGNED]. 5217** </ul>)^ 5218** ^The eTextRep argument determines the encoding of strings passed 5219** to the collating function callback, xCallback. 5220** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5221** force strings to be UTF16 with native byte order. 5222** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5223** on an even byte address. 5224** 5225** ^The fourth argument, pArg, is an application data pointer that is passed 5226** through as the first argument to the collating function callback. 5227** 5228** ^The fifth argument, xCallback, is a pointer to the collating function. 5229** ^Multiple collating functions can be registered using the same name but 5230** with different eTextRep parameters and SQLite will use whichever 5231** function requires the least amount of data transformation. 5232** ^If the xCallback argument is NULL then the collating function is 5233** deleted. ^When all collating functions having the same name are deleted, 5234** that collation is no longer usable. 5235** 5236** ^The collating function callback is invoked with a copy of the pArg 5237** application data pointer and with two strings in the encoding specified 5238** by the eTextRep argument. The collating function must return an 5239** integer that is negative, zero, or positive 5240** if the first string is less than, equal to, or greater than the second, 5241** respectively. A collating function must always return the same answer 5242** given the same inputs. If two or more collating functions are registered 5243** to the same collation name (using different eTextRep values) then all 5244** must give an equivalent answer when invoked with equivalent strings. 5245** The collating function must obey the following properties for all 5246** strings A, B, and C: 5247** 5248** <ol> 5249** <li> If A==B then B==A. 5250** <li> If A==B and B==C then A==C. 5251** <li> If A<B THEN B>A. 5252** <li> If A<B and B<C then A<C. 5253** </ol> 5254** 5255** If a collating function fails any of the above constraints and that 5256** collating function is registered and used, then the behavior of SQLite 5257** is undefined. 5258** 5259** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5260** with the addition that the xDestroy callback is invoked on pArg when 5261** the collating function is deleted. 5262** ^Collating functions are deleted when they are overridden by later 5263** calls to the collation creation functions or when the 5264** [database connection] is closed using [sqlite3_close()]. 5265** 5266** ^The xDestroy callback is <u>not</u> called if the 5267** sqlite3_create_collation_v2() function fails. Applications that invoke 5268** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5269** check the return code and dispose of the application data pointer 5270** themselves rather than expecting SQLite to deal with it for them. 5271** This is different from every other SQLite interface. The inconsistency 5272** is unfortunate but cannot be changed without breaking backwards 5273** compatibility. 5274** 5275** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5276*/ 5277int sqlite3_create_collation( 5278 sqlite3*, 5279 const char *zName, 5280 int eTextRep, 5281 void *pArg, 5282 int(*xCompare)(void*,int,const void*,int,const void*) 5283); 5284int sqlite3_create_collation_v2( 5285 sqlite3*, 5286 const char *zName, 5287 int eTextRep, 5288 void *pArg, 5289 int(*xCompare)(void*,int,const void*,int,const void*), 5290 void(*xDestroy)(void*) 5291); 5292int sqlite3_create_collation16( 5293 sqlite3*, 5294 const void *zName, 5295 int eTextRep, 5296 void *pArg, 5297 int(*xCompare)(void*,int,const void*,int,const void*) 5298); 5299 5300/* 5301** CAPI3REF: Collation Needed Callbacks 5302** METHOD: sqlite3 5303** 5304** ^To avoid having to register all collation sequences before a database 5305** can be used, a single callback function may be registered with the 5306** [database connection] to be invoked whenever an undefined collation 5307** sequence is required. 5308** 5309** ^If the function is registered using the sqlite3_collation_needed() API, 5310** then it is passed the names of undefined collation sequences as strings 5311** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5312** the names are passed as UTF-16 in machine native byte order. 5313** ^A call to either function replaces the existing collation-needed callback. 5314** 5315** ^(When the callback is invoked, the first argument passed is a copy 5316** of the second argument to sqlite3_collation_needed() or 5317** sqlite3_collation_needed16(). The second argument is the database 5318** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5319** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5320** sequence function required. The fourth parameter is the name of the 5321** required collation sequence.)^ 5322** 5323** The callback function should register the desired collation using 5324** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5325** [sqlite3_create_collation_v2()]. 5326*/ 5327int sqlite3_collation_needed( 5328 sqlite3*, 5329 void*, 5330 void(*)(void*,sqlite3*,int eTextRep,const char*) 5331); 5332int sqlite3_collation_needed16( 5333 sqlite3*, 5334 void*, 5335 void(*)(void*,sqlite3*,int eTextRep,const void*) 5336); 5337 5338#ifdef SQLITE_HAS_CODEC 5339/* 5340** Specify the key for an encrypted database. This routine should be 5341** called right after sqlite3_open(). 5342** 5343** The code to implement this API is not available in the public release 5344** of SQLite. 5345*/ 5346int sqlite3_key( 5347 sqlite3 *db, /* Database to be rekeyed */ 5348 const void *pKey, int nKey /* The key */ 5349); 5350int sqlite3_key_v2( 5351 sqlite3 *db, /* Database to be rekeyed */ 5352 const char *zDbName, /* Name of the database */ 5353 const void *pKey, int nKey /* The key */ 5354); 5355 5356/* 5357** Change the key on an open database. If the current database is not 5358** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5359** database is decrypted. 5360** 5361** The code to implement this API is not available in the public release 5362** of SQLite. 5363*/ 5364int sqlite3_rekey( 5365 sqlite3 *db, /* Database to be rekeyed */ 5366 const void *pKey, int nKey /* The new key */ 5367); 5368int sqlite3_rekey_v2( 5369 sqlite3 *db, /* Database to be rekeyed */ 5370 const char *zDbName, /* Name of the database */ 5371 const void *pKey, int nKey /* The new key */ 5372); 5373 5374/* 5375** Specify the activation key for a SEE database. Unless 5376** activated, none of the SEE routines will work. 5377*/ 5378void sqlite3_activate_see( 5379 const char *zPassPhrase /* Activation phrase */ 5380); 5381#endif 5382 5383#ifdef SQLITE_ENABLE_CEROD 5384/* 5385** Specify the activation key for a CEROD database. Unless 5386** activated, none of the CEROD routines will work. 5387*/ 5388void sqlite3_activate_cerod( 5389 const char *zPassPhrase /* Activation phrase */ 5390); 5391#endif 5392 5393/* 5394** CAPI3REF: Suspend Execution For A Short Time 5395** 5396** The sqlite3_sleep() function causes the current thread to suspend execution 5397** for at least a number of milliseconds specified in its parameter. 5398** 5399** If the operating system does not support sleep requests with 5400** millisecond time resolution, then the time will be rounded up to 5401** the nearest second. The number of milliseconds of sleep actually 5402** requested from the operating system is returned. 5403** 5404** ^SQLite implements this interface by calling the xSleep() 5405** method of the default [sqlite3_vfs] object. If the xSleep() method 5406** of the default VFS is not implemented correctly, or not implemented at 5407** all, then the behavior of sqlite3_sleep() may deviate from the description 5408** in the previous paragraphs. 5409*/ 5410int sqlite3_sleep(int); 5411 5412/* 5413** CAPI3REF: Name Of The Folder Holding Temporary Files 5414** 5415** ^(If this global variable is made to point to a string which is 5416** the name of a folder (a.k.a. directory), then all temporary files 5417** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5418** will be placed in that directory.)^ ^If this variable 5419** is a NULL pointer, then SQLite performs a search for an appropriate 5420** temporary file directory. 5421** 5422** Applications are strongly discouraged from using this global variable. 5423** It is required to set a temporary folder on Windows Runtime (WinRT). 5424** But for all other platforms, it is highly recommended that applications 5425** neither read nor write this variable. This global variable is a relic 5426** that exists for backwards compatibility of legacy applications and should 5427** be avoided in new projects. 5428** 5429** It is not safe to read or modify this variable in more than one 5430** thread at a time. It is not safe to read or modify this variable 5431** if a [database connection] is being used at the same time in a separate 5432** thread. 5433** It is intended that this variable be set once 5434** as part of process initialization and before any SQLite interface 5435** routines have been called and that this variable remain unchanged 5436** thereafter. 5437** 5438** ^The [temp_store_directory pragma] may modify this variable and cause 5439** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5440** the [temp_store_directory pragma] always assumes that any string 5441** that this variable points to is held in memory obtained from 5442** [sqlite3_malloc] and the pragma may attempt to free that memory 5443** using [sqlite3_free]. 5444** Hence, if this variable is modified directly, either it should be 5445** made NULL or made to point to memory obtained from [sqlite3_malloc] 5446** or else the use of the [temp_store_directory pragma] should be avoided. 5447** Except when requested by the [temp_store_directory pragma], SQLite 5448** does not free the memory that sqlite3_temp_directory points to. If 5449** the application wants that memory to be freed, it must do 5450** so itself, taking care to only do so after all [database connection] 5451** objects have been destroyed. 5452** 5453** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5454** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5455** features that require the use of temporary files may fail. Here is an 5456** example of how to do this using C++ with the Windows Runtime: 5457** 5458** <blockquote><pre> 5459** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5460** TemporaryFolder->Path->Data(); 5461** char zPathBuf[MAX_PATH + 1]; 5462** memset(zPathBuf, 0, sizeof(zPathBuf)); 5463** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5464** NULL, NULL); 5465** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5466** </pre></blockquote> 5467*/ 5468SQLITE_EXTERN char *sqlite3_temp_directory; 5469 5470/* 5471** CAPI3REF: Name Of The Folder Holding Database Files 5472** 5473** ^(If this global variable is made to point to a string which is 5474** the name of a folder (a.k.a. directory), then all database files 5475** specified with a relative pathname and created or accessed by 5476** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5477** to be relative to that directory.)^ ^If this variable is a NULL 5478** pointer, then SQLite assumes that all database files specified 5479** with a relative pathname are relative to the current directory 5480** for the process. Only the windows VFS makes use of this global 5481** variable; it is ignored by the unix VFS. 5482** 5483** Changing the value of this variable while a database connection is 5484** open can result in a corrupt database. 5485** 5486** It is not safe to read or modify this variable in more than one 5487** thread at a time. It is not safe to read or modify this variable 5488** if a [database connection] is being used at the same time in a separate 5489** thread. 5490** It is intended that this variable be set once 5491** as part of process initialization and before any SQLite interface 5492** routines have been called and that this variable remain unchanged 5493** thereafter. 5494** 5495** ^The [data_store_directory pragma] may modify this variable and cause 5496** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5497** the [data_store_directory pragma] always assumes that any string 5498** that this variable points to is held in memory obtained from 5499** [sqlite3_malloc] and the pragma may attempt to free that memory 5500** using [sqlite3_free]. 5501** Hence, if this variable is modified directly, either it should be 5502** made NULL or made to point to memory obtained from [sqlite3_malloc] 5503** or else the use of the [data_store_directory pragma] should be avoided. 5504*/ 5505SQLITE_EXTERN char *sqlite3_data_directory; 5506 5507/* 5508** CAPI3REF: Test For Auto-Commit Mode 5509** KEYWORDS: {autocommit mode} 5510** METHOD: sqlite3 5511** 5512** ^The sqlite3_get_autocommit() interface returns non-zero or 5513** zero if the given database connection is or is not in autocommit mode, 5514** respectively. ^Autocommit mode is on by default. 5515** ^Autocommit mode is disabled by a [BEGIN] statement. 5516** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5517** 5518** If certain kinds of errors occur on a statement within a multi-statement 5519** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5520** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5521** transaction might be rolled back automatically. The only way to 5522** find out whether SQLite automatically rolled back the transaction after 5523** an error is to use this function. 5524** 5525** If another thread changes the autocommit status of the database 5526** connection while this routine is running, then the return value 5527** is undefined. 5528*/ 5529int sqlite3_get_autocommit(sqlite3*); 5530 5531/* 5532** CAPI3REF: Find The Database Handle Of A Prepared Statement 5533** METHOD: sqlite3_stmt 5534** 5535** ^The sqlite3_db_handle interface returns the [database connection] handle 5536** to which a [prepared statement] belongs. ^The [database connection] 5537** returned by sqlite3_db_handle is the same [database connection] 5538** that was the first argument 5539** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5540** create the statement in the first place. 5541*/ 5542sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5543 5544/* 5545** CAPI3REF: Return The Filename For A Database Connection 5546** METHOD: sqlite3 5547** 5548** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5549** associated with database N of connection D. ^The main database file 5550** has the name "main". If there is no attached database N on the database 5551** connection D, or if database N is a temporary or in-memory database, then 5552** a NULL pointer is returned. 5553** 5554** ^The filename returned by this function is the output of the 5555** xFullPathname method of the [VFS]. ^In other words, the filename 5556** will be an absolute pathname, even if the filename used 5557** to open the database originally was a URI or relative pathname. 5558*/ 5559const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5560 5561/* 5562** CAPI3REF: Determine if a database is read-only 5563** METHOD: sqlite3 5564** 5565** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5566** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5567** the name of a database on connection D. 5568*/ 5569int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5570 5571/* 5572** CAPI3REF: Find the next prepared statement 5573** METHOD: sqlite3 5574** 5575** ^This interface returns a pointer to the next [prepared statement] after 5576** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5577** then this interface returns a pointer to the first prepared statement 5578** associated with the database connection pDb. ^If no prepared statement 5579** satisfies the conditions of this routine, it returns NULL. 5580** 5581** The [database connection] pointer D in a call to 5582** [sqlite3_next_stmt(D,S)] must refer to an open database 5583** connection and in particular must not be a NULL pointer. 5584*/ 5585sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5586 5587/* 5588** CAPI3REF: Commit And Rollback Notification Callbacks 5589** METHOD: sqlite3 5590** 5591** ^The sqlite3_commit_hook() interface registers a callback 5592** function to be invoked whenever a transaction is [COMMIT | committed]. 5593** ^Any callback set by a previous call to sqlite3_commit_hook() 5594** for the same database connection is overridden. 5595** ^The sqlite3_rollback_hook() interface registers a callback 5596** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5597** ^Any callback set by a previous call to sqlite3_rollback_hook() 5598** for the same database connection is overridden. 5599** ^The pArg argument is passed through to the callback. 5600** ^If the callback on a commit hook function returns non-zero, 5601** then the commit is converted into a rollback. 5602** 5603** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5604** return the P argument from the previous call of the same function 5605** on the same [database connection] D, or NULL for 5606** the first call for each function on D. 5607** 5608** The commit and rollback hook callbacks are not reentrant. 5609** The callback implementation must not do anything that will modify 5610** the database connection that invoked the callback. Any actions 5611** to modify the database connection must be deferred until after the 5612** completion of the [sqlite3_step()] call that triggered the commit 5613** or rollback hook in the first place. 5614** Note that running any other SQL statements, including SELECT statements, 5615** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5616** the database connections for the meaning of "modify" in this paragraph. 5617** 5618** ^Registering a NULL function disables the callback. 5619** 5620** ^When the commit hook callback routine returns zero, the [COMMIT] 5621** operation is allowed to continue normally. ^If the commit hook 5622** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5623** ^The rollback hook is invoked on a rollback that results from a commit 5624** hook returning non-zero, just as it would be with any other rollback. 5625** 5626** ^For the purposes of this API, a transaction is said to have been 5627** rolled back if an explicit "ROLLBACK" statement is executed, or 5628** an error or constraint causes an implicit rollback to occur. 5629** ^The rollback callback is not invoked if a transaction is 5630** automatically rolled back because the database connection is closed. 5631** 5632** See also the [sqlite3_update_hook()] interface. 5633*/ 5634void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5635void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5636 5637/* 5638** CAPI3REF: Data Change Notification Callbacks 5639** METHOD: sqlite3 5640** 5641** ^The sqlite3_update_hook() interface registers a callback function 5642** with the [database connection] identified by the first argument 5643** to be invoked whenever a row is updated, inserted or deleted in 5644** a [rowid table]. 5645** ^Any callback set by a previous call to this function 5646** for the same database connection is overridden. 5647** 5648** ^The second argument is a pointer to the function to invoke when a 5649** row is updated, inserted or deleted in a rowid table. 5650** ^The first argument to the callback is a copy of the third argument 5651** to sqlite3_update_hook(). 5652** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5653** or [SQLITE_UPDATE], depending on the operation that caused the callback 5654** to be invoked. 5655** ^The third and fourth arguments to the callback contain pointers to the 5656** database and table name containing the affected row. 5657** ^The final callback parameter is the [rowid] of the row. 5658** ^In the case of an update, this is the [rowid] after the update takes place. 5659** 5660** ^(The update hook is not invoked when internal system tables are 5661** modified (i.e. sqlite_master and sqlite_sequence).)^ 5662** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5663** 5664** ^In the current implementation, the update hook 5665** is not invoked when conflicting rows are deleted because of an 5666** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5667** invoked when rows are deleted using the [truncate optimization]. 5668** The exceptions defined in this paragraph might change in a future 5669** release of SQLite. 5670** 5671** The update hook implementation must not do anything that will modify 5672** the database connection that invoked the update hook. Any actions 5673** to modify the database connection must be deferred until after the 5674** completion of the [sqlite3_step()] call that triggered the update hook. 5675** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5676** database connections for the meaning of "modify" in this paragraph. 5677** 5678** ^The sqlite3_update_hook(D,C,P) function 5679** returns the P argument from the previous call 5680** on the same [database connection] D, or NULL for 5681** the first call on D. 5682** 5683** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5684** and [sqlite3_preupdate_hook()] interfaces. 5685*/ 5686void *sqlite3_update_hook( 5687 sqlite3*, 5688 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5689 void* 5690); 5691 5692/* 5693** CAPI3REF: Enable Or Disable Shared Pager Cache 5694** 5695** ^(This routine enables or disables the sharing of the database cache 5696** and schema data structures between [database connection | connections] 5697** to the same database. Sharing is enabled if the argument is true 5698** and disabled if the argument is false.)^ 5699** 5700** ^Cache sharing is enabled and disabled for an entire process. 5701** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5702** In prior versions of SQLite, 5703** sharing was enabled or disabled for each thread separately. 5704** 5705** ^(The cache sharing mode set by this interface effects all subsequent 5706** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5707** Existing database connections continue use the sharing mode 5708** that was in effect at the time they were opened.)^ 5709** 5710** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5711** successfully. An [error code] is returned otherwise.)^ 5712** 5713** ^Shared cache is disabled by default. But this might change in 5714** future releases of SQLite. Applications that care about shared 5715** cache setting should set it explicitly. 5716** 5717** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5718** and will always return SQLITE_MISUSE. On those systems, 5719** shared cache mode should be enabled per-database connection via 5720** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5721** 5722** This interface is threadsafe on processors where writing a 5723** 32-bit integer is atomic. 5724** 5725** See Also: [SQLite Shared-Cache Mode] 5726*/ 5727int sqlite3_enable_shared_cache(int); 5728 5729/* 5730** CAPI3REF: Attempt To Free Heap Memory 5731** 5732** ^The sqlite3_release_memory() interface attempts to free N bytes 5733** of heap memory by deallocating non-essential memory allocations 5734** held by the database library. Memory used to cache database 5735** pages to improve performance is an example of non-essential memory. 5736** ^sqlite3_release_memory() returns the number of bytes actually freed, 5737** which might be more or less than the amount requested. 5738** ^The sqlite3_release_memory() routine is a no-op returning zero 5739** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5740** 5741** See also: [sqlite3_db_release_memory()] 5742*/ 5743int sqlite3_release_memory(int); 5744 5745/* 5746** CAPI3REF: Free Memory Used By A Database Connection 5747** METHOD: sqlite3 5748** 5749** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5750** memory as possible from database connection D. Unlike the 5751** [sqlite3_release_memory()] interface, this interface is in effect even 5752** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5753** omitted. 5754** 5755** See also: [sqlite3_release_memory()] 5756*/ 5757int sqlite3_db_release_memory(sqlite3*); 5758 5759/* 5760** CAPI3REF: Impose A Limit On Heap Size 5761** 5762** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5763** soft limit on the amount of heap memory that may be allocated by SQLite. 5764** ^SQLite strives to keep heap memory utilization below the soft heap 5765** limit by reducing the number of pages held in the page cache 5766** as heap memory usages approaches the limit. 5767** ^The soft heap limit is "soft" because even though SQLite strives to stay 5768** below the limit, it will exceed the limit rather than generate 5769** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5770** is advisory only. 5771** 5772** ^The return value from sqlite3_soft_heap_limit64() is the size of 5773** the soft heap limit prior to the call, or negative in the case of an 5774** error. ^If the argument N is negative 5775** then no change is made to the soft heap limit. Hence, the current 5776** size of the soft heap limit can be determined by invoking 5777** sqlite3_soft_heap_limit64() with a negative argument. 5778** 5779** ^If the argument N is zero then the soft heap limit is disabled. 5780** 5781** ^(The soft heap limit is not enforced in the current implementation 5782** if one or more of following conditions are true: 5783** 5784** <ul> 5785** <li> The soft heap limit is set to zero. 5786** <li> Memory accounting is disabled using a combination of the 5787** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5788** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5789** <li> An alternative page cache implementation is specified using 5790** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5791** <li> The page cache allocates from its own memory pool supplied 5792** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5793** from the heap. 5794** </ul>)^ 5795** 5796** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5797** the soft heap limit is enforced 5798** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5799** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5800** the soft heap limit is enforced on every memory allocation. Without 5801** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5802** when memory is allocated by the page cache. Testing suggests that because 5803** the page cache is the predominate memory user in SQLite, most 5804** applications will achieve adequate soft heap limit enforcement without 5805** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5806** 5807** The circumstances under which SQLite will enforce the soft heap limit may 5808** changes in future releases of SQLite. 5809*/ 5810sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5811 5812/* 5813** CAPI3REF: Deprecated Soft Heap Limit Interface 5814** DEPRECATED 5815** 5816** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5817** interface. This routine is provided for historical compatibility 5818** only. All new applications should use the 5819** [sqlite3_soft_heap_limit64()] interface rather than this one. 5820*/ 5821SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5822 5823 5824/* 5825** CAPI3REF: Extract Metadata About A Column Of A Table 5826** METHOD: sqlite3 5827** 5828** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5829** information about column C of table T in database D 5830** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5831** interface returns SQLITE_OK and fills in the non-NULL pointers in 5832** the final five arguments with appropriate values if the specified 5833** column exists. ^The sqlite3_table_column_metadata() interface returns 5834** SQLITE_ERROR and if the specified column does not exist. 5835** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5836** NULL pointer, then this routine simply checks for the existence of the 5837** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5838** does not. If the table name parameter T in a call to 5839** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5840** undefined behavior. 5841** 5842** ^The column is identified by the second, third and fourth parameters to 5843** this function. ^(The second parameter is either the name of the database 5844** (i.e. "main", "temp", or an attached database) containing the specified 5845** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5846** for the table using the same algorithm used by the database engine to 5847** resolve unqualified table references. 5848** 5849** ^The third and fourth parameters to this function are the table and column 5850** name of the desired column, respectively. 5851** 5852** ^Metadata is returned by writing to the memory locations passed as the 5th 5853** and subsequent parameters to this function. ^Any of these arguments may be 5854** NULL, in which case the corresponding element of metadata is omitted. 5855** 5856** ^(<blockquote> 5857** <table border="1"> 5858** <tr><th> Parameter <th> Output<br>Type <th> Description 5859** 5860** <tr><td> 5th <td> const char* <td> Data type 5861** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5862** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5863** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5864** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5865** </table> 5866** </blockquote>)^ 5867** 5868** ^The memory pointed to by the character pointers returned for the 5869** declaration type and collation sequence is valid until the next 5870** call to any SQLite API function. 5871** 5872** ^If the specified table is actually a view, an [error code] is returned. 5873** 5874** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5875** is not a [WITHOUT ROWID] table and an 5876** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5877** parameters are set for the explicitly declared column. ^(If there is no 5878** [INTEGER PRIMARY KEY] column, then the outputs 5879** for the [rowid] are set as follows: 5880** 5881** <pre> 5882** data type: "INTEGER" 5883** collation sequence: "BINARY" 5884** not null: 0 5885** primary key: 1 5886** auto increment: 0 5887** </pre>)^ 5888** 5889** ^This function causes all database schemas to be read from disk and 5890** parsed, if that has not already been done, and returns an error if 5891** any errors are encountered while loading the schema. 5892*/ 5893int sqlite3_table_column_metadata( 5894 sqlite3 *db, /* Connection handle */ 5895 const char *zDbName, /* Database name or NULL */ 5896 const char *zTableName, /* Table name */ 5897 const char *zColumnName, /* Column name */ 5898 char const **pzDataType, /* OUTPUT: Declared data type */ 5899 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5900 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5901 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5902 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5903); 5904 5905/* 5906** CAPI3REF: Load An Extension 5907** METHOD: sqlite3 5908** 5909** ^This interface loads an SQLite extension library from the named file. 5910** 5911** ^The sqlite3_load_extension() interface attempts to load an 5912** [SQLite extension] library contained in the file zFile. If 5913** the file cannot be loaded directly, attempts are made to load 5914** with various operating-system specific extensions added. 5915** So for example, if "samplelib" cannot be loaded, then names like 5916** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5917** be tried also. 5918** 5919** ^The entry point is zProc. 5920** ^(zProc may be 0, in which case SQLite will try to come up with an 5921** entry point name on its own. It first tries "sqlite3_extension_init". 5922** If that does not work, it constructs a name "sqlite3_X_init" where the 5923** X is consists of the lower-case equivalent of all ASCII alphabetic 5924** characters in the filename from the last "/" to the first following 5925** "." and omitting any initial "lib".)^ 5926** ^The sqlite3_load_extension() interface returns 5927** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5928** ^If an error occurs and pzErrMsg is not 0, then the 5929** [sqlite3_load_extension()] interface shall attempt to 5930** fill *pzErrMsg with error message text stored in memory 5931** obtained from [sqlite3_malloc()]. The calling function 5932** should free this memory by calling [sqlite3_free()]. 5933** 5934** ^Extension loading must be enabled using 5935** [sqlite3_enable_load_extension()] or 5936** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5937** prior to calling this API, 5938** otherwise an error will be returned. 5939** 5940** <b>Security warning:</b> It is recommended that the 5941** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5942** interface. The use of the [sqlite3_enable_load_extension()] interface 5943** should be avoided. This will keep the SQL function [load_extension()] 5944** disabled and prevent SQL injections from giving attackers 5945** access to extension loading capabilities. 5946** 5947** See also the [load_extension() SQL function]. 5948*/ 5949int sqlite3_load_extension( 5950 sqlite3 *db, /* Load the extension into this database connection */ 5951 const char *zFile, /* Name of the shared library containing extension */ 5952 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5953 char **pzErrMsg /* Put error message here if not 0 */ 5954); 5955 5956/* 5957** CAPI3REF: Enable Or Disable Extension Loading 5958** METHOD: sqlite3 5959** 5960** ^So as not to open security holes in older applications that are 5961** unprepared to deal with [extension loading], and as a means of disabling 5962** [extension loading] while evaluating user-entered SQL, the following API 5963** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5964** 5965** ^Extension loading is off by default. 5966** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5967** to turn extension loading on and call it with onoff==0 to turn 5968** it back off again. 5969** 5970** ^This interface enables or disables both the C-API 5971** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5972** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5973** to enable or disable only the C-API.)^ 5974** 5975** <b>Security warning:</b> It is recommended that extension loading 5976** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5977** rather than this interface, so the [load_extension()] SQL function 5978** remains disabled. This will prevent SQL injections from giving attackers 5979** access to extension loading capabilities. 5980*/ 5981int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5982 5983/* 5984** CAPI3REF: Automatically Load Statically Linked Extensions 5985** 5986** ^This interface causes the xEntryPoint() function to be invoked for 5987** each new [database connection] that is created. The idea here is that 5988** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5989** that is to be automatically loaded into all new database connections. 5990** 5991** ^(Even though the function prototype shows that xEntryPoint() takes 5992** no arguments and returns void, SQLite invokes xEntryPoint() with three 5993** arguments and expects an integer result as if the signature of the 5994** entry point where as follows: 5995** 5996** <blockquote><pre> 5997** int xEntryPoint( 5998** sqlite3 *db, 5999** const char **pzErrMsg, 6000** const struct sqlite3_api_routines *pThunk 6001** ); 6002** </pre></blockquote>)^ 6003** 6004** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6005** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6006** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6007** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6008** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6009** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6010** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6011** 6012** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6013** on the list of automatic extensions is a harmless no-op. ^No entry point 6014** will be called more than once for each database connection that is opened. 6015** 6016** See also: [sqlite3_reset_auto_extension()] 6017** and [sqlite3_cancel_auto_extension()] 6018*/ 6019int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6020 6021/* 6022** CAPI3REF: Cancel Automatic Extension Loading 6023** 6024** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6025** initialization routine X that was registered using a prior call to 6026** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6027** routine returns 1 if initialization routine X was successfully 6028** unregistered and it returns 0 if X was not on the list of initialization 6029** routines. 6030*/ 6031int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6032 6033/* 6034** CAPI3REF: Reset Automatic Extension Loading 6035** 6036** ^This interface disables all automatic extensions previously 6037** registered using [sqlite3_auto_extension()]. 6038*/ 6039void sqlite3_reset_auto_extension(void); 6040 6041/* 6042** The interface to the virtual-table mechanism is currently considered 6043** to be experimental. The interface might change in incompatible ways. 6044** If this is a problem for you, do not use the interface at this time. 6045** 6046** When the virtual-table mechanism stabilizes, we will declare the 6047** interface fixed, support it indefinitely, and remove this comment. 6048*/ 6049 6050/* 6051** Structures used by the virtual table interface 6052*/ 6053typedef struct sqlite3_vtab sqlite3_vtab; 6054typedef struct sqlite3_index_info sqlite3_index_info; 6055typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6056typedef struct sqlite3_module sqlite3_module; 6057 6058/* 6059** CAPI3REF: Virtual Table Object 6060** KEYWORDS: sqlite3_module {virtual table module} 6061** 6062** This structure, sometimes called a "virtual table module", 6063** defines the implementation of a [virtual tables]. 6064** This structure consists mostly of methods for the module. 6065** 6066** ^A virtual table module is created by filling in a persistent 6067** instance of this structure and passing a pointer to that instance 6068** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6069** ^The registration remains valid until it is replaced by a different 6070** module or until the [database connection] closes. The content 6071** of this structure must not change while it is registered with 6072** any database connection. 6073*/ 6074struct sqlite3_module { 6075 int iVersion; 6076 int (*xCreate)(sqlite3*, void *pAux, 6077 int argc, const char *const*argv, 6078 sqlite3_vtab **ppVTab, char**); 6079 int (*xConnect)(sqlite3*, void *pAux, 6080 int argc, const char *const*argv, 6081 sqlite3_vtab **ppVTab, char**); 6082 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6083 int (*xDisconnect)(sqlite3_vtab *pVTab); 6084 int (*xDestroy)(sqlite3_vtab *pVTab); 6085 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6086 int (*xClose)(sqlite3_vtab_cursor*); 6087 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6088 int argc, sqlite3_value **argv); 6089 int (*xNext)(sqlite3_vtab_cursor*); 6090 int (*xEof)(sqlite3_vtab_cursor*); 6091 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6092 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6093 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6094 int (*xBegin)(sqlite3_vtab *pVTab); 6095 int (*xSync)(sqlite3_vtab *pVTab); 6096 int (*xCommit)(sqlite3_vtab *pVTab); 6097 int (*xRollback)(sqlite3_vtab *pVTab); 6098 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6099 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6100 void **ppArg); 6101 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6102 /* The methods above are in version 1 of the sqlite_module object. Those 6103 ** below are for version 2 and greater. */ 6104 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6105 int (*xRelease)(sqlite3_vtab *pVTab, int); 6106 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6107}; 6108 6109/* 6110** CAPI3REF: Virtual Table Indexing Information 6111** KEYWORDS: sqlite3_index_info 6112** 6113** The sqlite3_index_info structure and its substructures is used as part 6114** of the [virtual table] interface to 6115** pass information into and receive the reply from the [xBestIndex] 6116** method of a [virtual table module]. The fields under **Inputs** are the 6117** inputs to xBestIndex and are read-only. xBestIndex inserts its 6118** results into the **Outputs** fields. 6119** 6120** ^(The aConstraint[] array records WHERE clause constraints of the form: 6121** 6122** <blockquote>column OP expr</blockquote> 6123** 6124** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6125** stored in aConstraint[].op using one of the 6126** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6127** ^(The index of the column is stored in 6128** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6129** expr on the right-hand side can be evaluated (and thus the constraint 6130** is usable) and false if it cannot.)^ 6131** 6132** ^The optimizer automatically inverts terms of the form "expr OP column" 6133** and makes other simplifications to the WHERE clause in an attempt to 6134** get as many WHERE clause terms into the form shown above as possible. 6135** ^The aConstraint[] array only reports WHERE clause terms that are 6136** relevant to the particular virtual table being queried. 6137** 6138** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6139** ^Each term of aOrderBy records a column of the ORDER BY clause. 6140** 6141** The colUsed field indicates which columns of the virtual table may be 6142** required by the current scan. Virtual table columns are numbered from 6143** zero in the order in which they appear within the CREATE TABLE statement 6144** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6145** the corresponding bit is set within the colUsed mask if the column may be 6146** required by SQLite. If the table has at least 64 columns and any column 6147** to the right of the first 63 is required, then bit 63 of colUsed is also 6148** set. In other words, column iCol may be required if the expression 6149** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6150** non-zero. 6151** 6152** The [xBestIndex] method must fill aConstraintUsage[] with information 6153** about what parameters to pass to xFilter. ^If argvIndex>0 then 6154** the right-hand side of the corresponding aConstraint[] is evaluated 6155** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6156** is true, then the constraint is assumed to be fully handled by the 6157** virtual table and is not checked again by SQLite.)^ 6158** 6159** ^The idxNum and idxPtr values are recorded and passed into the 6160** [xFilter] method. 6161** ^[sqlite3_free()] is used to free idxPtr if and only if 6162** needToFreeIdxPtr is true. 6163** 6164** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6165** the correct order to satisfy the ORDER BY clause so that no separate 6166** sorting step is required. 6167** 6168** ^The estimatedCost value is an estimate of the cost of a particular 6169** strategy. A cost of N indicates that the cost of the strategy is similar 6170** to a linear scan of an SQLite table with N rows. A cost of log(N) 6171** indicates that the expense of the operation is similar to that of a 6172** binary search on a unique indexed field of an SQLite table with N rows. 6173** 6174** ^The estimatedRows value is an estimate of the number of rows that 6175** will be returned by the strategy. 6176** 6177** The xBestIndex method may optionally populate the idxFlags field with a 6178** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6179** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6180** assumes that the strategy may visit at most one row. 6181** 6182** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6183** SQLite also assumes that if a call to the xUpdate() method is made as 6184** part of the same statement to delete or update a virtual table row and the 6185** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6186** any database changes. In other words, if the xUpdate() returns 6187** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6188** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6189** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6190** the xUpdate method are automatically rolled back by SQLite. 6191** 6192** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6193** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6194** If a virtual table extension is 6195** used with an SQLite version earlier than 3.8.2, the results of attempting 6196** to read or write the estimatedRows field are undefined (but are likely 6197** to included crashing the application). The estimatedRows field should 6198** therefore only be used if [sqlite3_libversion_number()] returns a 6199** value greater than or equal to 3008002. Similarly, the idxFlags field 6200** was added for [version 3.9.0] ([dateof:3.9.0]). 6201** It may therefore only be used if 6202** sqlite3_libversion_number() returns a value greater than or equal to 6203** 3009000. 6204*/ 6205struct sqlite3_index_info { 6206 /* Inputs */ 6207 int nConstraint; /* Number of entries in aConstraint */ 6208 struct sqlite3_index_constraint { 6209 int iColumn; /* Column constrained. -1 for ROWID */ 6210 unsigned char op; /* Constraint operator */ 6211 unsigned char usable; /* True if this constraint is usable */ 6212 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6213 } *aConstraint; /* Table of WHERE clause constraints */ 6214 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6215 struct sqlite3_index_orderby { 6216 int iColumn; /* Column number */ 6217 unsigned char desc; /* True for DESC. False for ASC. */ 6218 } *aOrderBy; /* The ORDER BY clause */ 6219 /* Outputs */ 6220 struct sqlite3_index_constraint_usage { 6221 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6222 unsigned char omit; /* Do not code a test for this constraint */ 6223 } *aConstraintUsage; 6224 int idxNum; /* Number used to identify the index */ 6225 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6226 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6227 int orderByConsumed; /* True if output is already ordered */ 6228 double estimatedCost; /* Estimated cost of using this index */ 6229 /* Fields below are only available in SQLite 3.8.2 and later */ 6230 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6231 /* Fields below are only available in SQLite 3.9.0 and later */ 6232 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6233 /* Fields below are only available in SQLite 3.10.0 and later */ 6234 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6235}; 6236 6237/* 6238** CAPI3REF: Virtual Table Scan Flags 6239*/ 6240#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6241 6242/* 6243** CAPI3REF: Virtual Table Constraint Operator Codes 6244** 6245** These macros defined the allowed values for the 6246** [sqlite3_index_info].aConstraint[].op field. Each value represents 6247** an operator that is part of a constraint term in the wHERE clause of 6248** a query that uses a [virtual table]. 6249*/ 6250#define SQLITE_INDEX_CONSTRAINT_EQ 2 6251#define SQLITE_INDEX_CONSTRAINT_GT 4 6252#define SQLITE_INDEX_CONSTRAINT_LE 8 6253#define SQLITE_INDEX_CONSTRAINT_LT 16 6254#define SQLITE_INDEX_CONSTRAINT_GE 32 6255#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6256#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6257#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6258#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6259#define SQLITE_INDEX_CONSTRAINT_NE 68 6260#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6261#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6262#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6263#define SQLITE_INDEX_CONSTRAINT_IS 72 6264 6265/* 6266** CAPI3REF: Register A Virtual Table Implementation 6267** METHOD: sqlite3 6268** 6269** ^These routines are used to register a new [virtual table module] name. 6270** ^Module names must be registered before 6271** creating a new [virtual table] using the module and before using a 6272** preexisting [virtual table] for the module. 6273** 6274** ^The module name is registered on the [database connection] specified 6275** by the first parameter. ^The name of the module is given by the 6276** second parameter. ^The third parameter is a pointer to 6277** the implementation of the [virtual table module]. ^The fourth 6278** parameter is an arbitrary client data pointer that is passed through 6279** into the [xCreate] and [xConnect] methods of the virtual table module 6280** when a new virtual table is be being created or reinitialized. 6281** 6282** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6283** is a pointer to a destructor for the pClientData. ^SQLite will 6284** invoke the destructor function (if it is not NULL) when SQLite 6285** no longer needs the pClientData pointer. ^The destructor will also 6286** be invoked if the call to sqlite3_create_module_v2() fails. 6287** ^The sqlite3_create_module() 6288** interface is equivalent to sqlite3_create_module_v2() with a NULL 6289** destructor. 6290*/ 6291int sqlite3_create_module( 6292 sqlite3 *db, /* SQLite connection to register module with */ 6293 const char *zName, /* Name of the module */ 6294 const sqlite3_module *p, /* Methods for the module */ 6295 void *pClientData /* Client data for xCreate/xConnect */ 6296); 6297int sqlite3_create_module_v2( 6298 sqlite3 *db, /* SQLite connection to register module with */ 6299 const char *zName, /* Name of the module */ 6300 const sqlite3_module *p, /* Methods for the module */ 6301 void *pClientData, /* Client data for xCreate/xConnect */ 6302 void(*xDestroy)(void*) /* Module destructor function */ 6303); 6304 6305/* 6306** CAPI3REF: Virtual Table Instance Object 6307** KEYWORDS: sqlite3_vtab 6308** 6309** Every [virtual table module] implementation uses a subclass 6310** of this object to describe a particular instance 6311** of the [virtual table]. Each subclass will 6312** be tailored to the specific needs of the module implementation. 6313** The purpose of this superclass is to define certain fields that are 6314** common to all module implementations. 6315** 6316** ^Virtual tables methods can set an error message by assigning a 6317** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6318** take care that any prior string is freed by a call to [sqlite3_free()] 6319** prior to assigning a new string to zErrMsg. ^After the error message 6320** is delivered up to the client application, the string will be automatically 6321** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6322*/ 6323struct sqlite3_vtab { 6324 const sqlite3_module *pModule; /* The module for this virtual table */ 6325 int nRef; /* Number of open cursors */ 6326 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6327 /* Virtual table implementations will typically add additional fields */ 6328}; 6329 6330/* 6331** CAPI3REF: Virtual Table Cursor Object 6332** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6333** 6334** Every [virtual table module] implementation uses a subclass of the 6335** following structure to describe cursors that point into the 6336** [virtual table] and are used 6337** to loop through the virtual table. Cursors are created using the 6338** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6339** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6340** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6341** of the module. Each module implementation will define 6342** the content of a cursor structure to suit its own needs. 6343** 6344** This superclass exists in order to define fields of the cursor that 6345** are common to all implementations. 6346*/ 6347struct sqlite3_vtab_cursor { 6348 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6349 /* Virtual table implementations will typically add additional fields */ 6350}; 6351 6352/* 6353** CAPI3REF: Declare The Schema Of A Virtual Table 6354** 6355** ^The [xCreate] and [xConnect] methods of a 6356** [virtual table module] call this interface 6357** to declare the format (the names and datatypes of the columns) of 6358** the virtual tables they implement. 6359*/ 6360int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6361 6362/* 6363** CAPI3REF: Overload A Function For A Virtual Table 6364** METHOD: sqlite3 6365** 6366** ^(Virtual tables can provide alternative implementations of functions 6367** using the [xFindFunction] method of the [virtual table module]. 6368** But global versions of those functions 6369** must exist in order to be overloaded.)^ 6370** 6371** ^(This API makes sure a global version of a function with a particular 6372** name and number of parameters exists. If no such function exists 6373** before this API is called, a new function is created.)^ ^The implementation 6374** of the new function always causes an exception to be thrown. So 6375** the new function is not good for anything by itself. Its only 6376** purpose is to be a placeholder function that can be overloaded 6377** by a [virtual table]. 6378*/ 6379int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6380 6381/* 6382** The interface to the virtual-table mechanism defined above (back up 6383** to a comment remarkably similar to this one) is currently considered 6384** to be experimental. The interface might change in incompatible ways. 6385** If this is a problem for you, do not use the interface at this time. 6386** 6387** When the virtual-table mechanism stabilizes, we will declare the 6388** interface fixed, support it indefinitely, and remove this comment. 6389*/ 6390 6391/* 6392** CAPI3REF: A Handle To An Open BLOB 6393** KEYWORDS: {BLOB handle} {BLOB handles} 6394** 6395** An instance of this object represents an open BLOB on which 6396** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6397** ^Objects of this type are created by [sqlite3_blob_open()] 6398** and destroyed by [sqlite3_blob_close()]. 6399** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6400** can be used to read or write small subsections of the BLOB. 6401** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6402*/ 6403typedef struct sqlite3_blob sqlite3_blob; 6404 6405/* 6406** CAPI3REF: Open A BLOB For Incremental I/O 6407** METHOD: sqlite3 6408** CONSTRUCTOR: sqlite3_blob 6409** 6410** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6411** in row iRow, column zColumn, table zTable in database zDb; 6412** in other words, the same BLOB that would be selected by: 6413** 6414** <pre> 6415** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6416** </pre>)^ 6417** 6418** ^(Parameter zDb is not the filename that contains the database, but 6419** rather the symbolic name of the database. For attached databases, this is 6420** the name that appears after the AS keyword in the [ATTACH] statement. 6421** For the main database file, the database name is "main". For TEMP 6422** tables, the database name is "temp".)^ 6423** 6424** ^If the flags parameter is non-zero, then the BLOB is opened for read 6425** and write access. ^If the flags parameter is zero, the BLOB is opened for 6426** read-only access. 6427** 6428** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6429** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6430** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6431** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6432** on *ppBlob after this function it returns. 6433** 6434** This function fails with SQLITE_ERROR if any of the following are true: 6435** <ul> 6436** <li> ^(Database zDb does not exist)^, 6437** <li> ^(Table zTable does not exist within database zDb)^, 6438** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6439** <li> ^(Column zColumn does not exist)^, 6440** <li> ^(Row iRow is not present in the table)^, 6441** <li> ^(The specified column of row iRow contains a value that is not 6442** a TEXT or BLOB value)^, 6443** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6444** constraint and the blob is being opened for read/write access)^, 6445** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6446** column zColumn is part of a [child key] definition and the blob is 6447** being opened for read/write access)^. 6448** </ul> 6449** 6450** ^Unless it returns SQLITE_MISUSE, this function sets the 6451** [database connection] error code and message accessible via 6452** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6453** 6454** A BLOB referenced by sqlite3_blob_open() may be read using the 6455** [sqlite3_blob_read()] interface and modified by using 6456** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6457** different row of the same table using the [sqlite3_blob_reopen()] 6458** interface. However, the column, table, or database of a [BLOB handle] 6459** cannot be changed after the [BLOB handle] is opened. 6460** 6461** ^(If the row that a BLOB handle points to is modified by an 6462** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6463** then the BLOB handle is marked as "expired". 6464** This is true if any column of the row is changed, even a column 6465** other than the one the BLOB handle is open on.)^ 6466** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6467** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6468** ^(Changes written into a BLOB prior to the BLOB expiring are not 6469** rolled back by the expiration of the BLOB. Such changes will eventually 6470** commit if the transaction continues to completion.)^ 6471** 6472** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6473** the opened blob. ^The size of a blob may not be changed by this 6474** interface. Use the [UPDATE] SQL command to change the size of a 6475** blob. 6476** 6477** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6478** and the built-in [zeroblob] SQL function may be used to create a 6479** zero-filled blob to read or write using the incremental-blob interface. 6480** 6481** To avoid a resource leak, every open [BLOB handle] should eventually 6482** be released by a call to [sqlite3_blob_close()]. 6483** 6484** See also: [sqlite3_blob_close()], 6485** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6486** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6487*/ 6488int sqlite3_blob_open( 6489 sqlite3*, 6490 const char *zDb, 6491 const char *zTable, 6492 const char *zColumn, 6493 sqlite3_int64 iRow, 6494 int flags, 6495 sqlite3_blob **ppBlob 6496); 6497 6498/* 6499** CAPI3REF: Move a BLOB Handle to a New Row 6500** METHOD: sqlite3_blob 6501** 6502** ^This function is used to move an existing [BLOB handle] so that it points 6503** to a different row of the same database table. ^The new row is identified 6504** by the rowid value passed as the second argument. Only the row can be 6505** changed. ^The database, table and column on which the blob handle is open 6506** remain the same. Moving an existing [BLOB handle] to a new row is 6507** faster than closing the existing handle and opening a new one. 6508** 6509** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6510** it must exist and there must be either a blob or text value stored in 6511** the nominated column.)^ ^If the new row is not present in the table, or if 6512** it does not contain a blob or text value, or if another error occurs, an 6513** SQLite error code is returned and the blob handle is considered aborted. 6514** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6515** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6516** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6517** always returns zero. 6518** 6519** ^This function sets the database handle error code and message. 6520*/ 6521int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6522 6523/* 6524** CAPI3REF: Close A BLOB Handle 6525** DESTRUCTOR: sqlite3_blob 6526** 6527** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6528** unconditionally. Even if this routine returns an error code, the 6529** handle is still closed.)^ 6530** 6531** ^If the blob handle being closed was opened for read-write access, and if 6532** the database is in auto-commit mode and there are no other open read-write 6533** blob handles or active write statements, the current transaction is 6534** committed. ^If an error occurs while committing the transaction, an error 6535** code is returned and the transaction rolled back. 6536** 6537** Calling this function with an argument that is not a NULL pointer or an 6538** open blob handle results in undefined behaviour. ^Calling this routine 6539** with a null pointer (such as would be returned by a failed call to 6540** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6541** is passed a valid open blob handle, the values returned by the 6542** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6543*/ 6544int sqlite3_blob_close(sqlite3_blob *); 6545 6546/* 6547** CAPI3REF: Return The Size Of An Open BLOB 6548** METHOD: sqlite3_blob 6549** 6550** ^Returns the size in bytes of the BLOB accessible via the 6551** successfully opened [BLOB handle] in its only argument. ^The 6552** incremental blob I/O routines can only read or overwriting existing 6553** blob content; they cannot change the size of a blob. 6554** 6555** This routine only works on a [BLOB handle] which has been created 6556** by a prior successful call to [sqlite3_blob_open()] and which has not 6557** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6558** to this routine results in undefined and probably undesirable behavior. 6559*/ 6560int sqlite3_blob_bytes(sqlite3_blob *); 6561 6562/* 6563** CAPI3REF: Read Data From A BLOB Incrementally 6564** METHOD: sqlite3_blob 6565** 6566** ^(This function is used to read data from an open [BLOB handle] into a 6567** caller-supplied buffer. N bytes of data are copied into buffer Z 6568** from the open BLOB, starting at offset iOffset.)^ 6569** 6570** ^If offset iOffset is less than N bytes from the end of the BLOB, 6571** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6572** less than zero, [SQLITE_ERROR] is returned and no data is read. 6573** ^The size of the blob (and hence the maximum value of N+iOffset) 6574** can be determined using the [sqlite3_blob_bytes()] interface. 6575** 6576** ^An attempt to read from an expired [BLOB handle] fails with an 6577** error code of [SQLITE_ABORT]. 6578** 6579** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6580** Otherwise, an [error code] or an [extended error code] is returned.)^ 6581** 6582** This routine only works on a [BLOB handle] which has been created 6583** by a prior successful call to [sqlite3_blob_open()] and which has not 6584** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6585** to this routine results in undefined and probably undesirable behavior. 6586** 6587** See also: [sqlite3_blob_write()]. 6588*/ 6589int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6590 6591/* 6592** CAPI3REF: Write Data Into A BLOB Incrementally 6593** METHOD: sqlite3_blob 6594** 6595** ^(This function is used to write data into an open [BLOB handle] from a 6596** caller-supplied buffer. N bytes of data are copied from the buffer Z 6597** into the open BLOB, starting at offset iOffset.)^ 6598** 6599** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6600** Otherwise, an [error code] or an [extended error code] is returned.)^ 6601** ^Unless SQLITE_MISUSE is returned, this function sets the 6602** [database connection] error code and message accessible via 6603** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6604** 6605** ^If the [BLOB handle] passed as the first argument was not opened for 6606** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6607** this function returns [SQLITE_READONLY]. 6608** 6609** This function may only modify the contents of the BLOB; it is 6610** not possible to increase the size of a BLOB using this API. 6611** ^If offset iOffset is less than N bytes from the end of the BLOB, 6612** [SQLITE_ERROR] is returned and no data is written. The size of the 6613** BLOB (and hence the maximum value of N+iOffset) can be determined 6614** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6615** than zero [SQLITE_ERROR] is returned and no data is written. 6616** 6617** ^An attempt to write to an expired [BLOB handle] fails with an 6618** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6619** before the [BLOB handle] expired are not rolled back by the 6620** expiration of the handle, though of course those changes might 6621** have been overwritten by the statement that expired the BLOB handle 6622** or by other independent statements. 6623** 6624** This routine only works on a [BLOB handle] which has been created 6625** by a prior successful call to [sqlite3_blob_open()] and which has not 6626** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6627** to this routine results in undefined and probably undesirable behavior. 6628** 6629** See also: [sqlite3_blob_read()]. 6630*/ 6631int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6632 6633/* 6634** CAPI3REF: Virtual File System Objects 6635** 6636** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6637** that SQLite uses to interact 6638** with the underlying operating system. Most SQLite builds come with a 6639** single default VFS that is appropriate for the host computer. 6640** New VFSes can be registered and existing VFSes can be unregistered. 6641** The following interfaces are provided. 6642** 6643** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6644** ^Names are case sensitive. 6645** ^Names are zero-terminated UTF-8 strings. 6646** ^If there is no match, a NULL pointer is returned. 6647** ^If zVfsName is NULL then the default VFS is returned. 6648** 6649** ^New VFSes are registered with sqlite3_vfs_register(). 6650** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6651** ^The same VFS can be registered multiple times without injury. 6652** ^To make an existing VFS into the default VFS, register it again 6653** with the makeDflt flag set. If two different VFSes with the 6654** same name are registered, the behavior is undefined. If a 6655** VFS is registered with a name that is NULL or an empty string, 6656** then the behavior is undefined. 6657** 6658** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6659** ^(If the default VFS is unregistered, another VFS is chosen as 6660** the default. The choice for the new VFS is arbitrary.)^ 6661*/ 6662sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6663int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6664int sqlite3_vfs_unregister(sqlite3_vfs*); 6665 6666/* 6667** CAPI3REF: Mutexes 6668** 6669** The SQLite core uses these routines for thread 6670** synchronization. Though they are intended for internal 6671** use by SQLite, code that links against SQLite is 6672** permitted to use any of these routines. 6673** 6674** The SQLite source code contains multiple implementations 6675** of these mutex routines. An appropriate implementation 6676** is selected automatically at compile-time. The following 6677** implementations are available in the SQLite core: 6678** 6679** <ul> 6680** <li> SQLITE_MUTEX_PTHREADS 6681** <li> SQLITE_MUTEX_W32 6682** <li> SQLITE_MUTEX_NOOP 6683** </ul> 6684** 6685** The SQLITE_MUTEX_NOOP implementation is a set of routines 6686** that does no real locking and is appropriate for use in 6687** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6688** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6689** and Windows. 6690** 6691** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6692** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6693** implementation is included with the library. In this case the 6694** application must supply a custom mutex implementation using the 6695** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6696** before calling sqlite3_initialize() or any other public sqlite3_ 6697** function that calls sqlite3_initialize(). 6698** 6699** ^The sqlite3_mutex_alloc() routine allocates a new 6700** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6701** routine returns NULL if it is unable to allocate the requested 6702** mutex. The argument to sqlite3_mutex_alloc() must one of these 6703** integer constants: 6704** 6705** <ul> 6706** <li> SQLITE_MUTEX_FAST 6707** <li> SQLITE_MUTEX_RECURSIVE 6708** <li> SQLITE_MUTEX_STATIC_MASTER 6709** <li> SQLITE_MUTEX_STATIC_MEM 6710** <li> SQLITE_MUTEX_STATIC_OPEN 6711** <li> SQLITE_MUTEX_STATIC_PRNG 6712** <li> SQLITE_MUTEX_STATIC_LRU 6713** <li> SQLITE_MUTEX_STATIC_PMEM 6714** <li> SQLITE_MUTEX_STATIC_APP1 6715** <li> SQLITE_MUTEX_STATIC_APP2 6716** <li> SQLITE_MUTEX_STATIC_APP3 6717** <li> SQLITE_MUTEX_STATIC_VFS1 6718** <li> SQLITE_MUTEX_STATIC_VFS2 6719** <li> SQLITE_MUTEX_STATIC_VFS3 6720** </ul> 6721** 6722** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6723** cause sqlite3_mutex_alloc() to create 6724** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6725** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6726** The mutex implementation does not need to make a distinction 6727** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6728** not want to. SQLite will only request a recursive mutex in 6729** cases where it really needs one. If a faster non-recursive mutex 6730** implementation is available on the host platform, the mutex subsystem 6731** might return such a mutex in response to SQLITE_MUTEX_FAST. 6732** 6733** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6734** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6735** a pointer to a static preexisting mutex. ^Nine static mutexes are 6736** used by the current version of SQLite. Future versions of SQLite 6737** may add additional static mutexes. Static mutexes are for internal 6738** use by SQLite only. Applications that use SQLite mutexes should 6739** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6740** SQLITE_MUTEX_RECURSIVE. 6741** 6742** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6743** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6744** returns a different mutex on every call. ^For the static 6745** mutex types, the same mutex is returned on every call that has 6746** the same type number. 6747** 6748** ^The sqlite3_mutex_free() routine deallocates a previously 6749** allocated dynamic mutex. Attempting to deallocate a static 6750** mutex results in undefined behavior. 6751** 6752** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6753** to enter a mutex. ^If another thread is already within the mutex, 6754** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6755** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6756** upon successful entry. ^(Mutexes created using 6757** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6758** In such cases, the 6759** mutex must be exited an equal number of times before another thread 6760** can enter.)^ If the same thread tries to enter any mutex other 6761** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6762** 6763** ^(Some systems (for example, Windows 95) do not support the operation 6764** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6765** will always return SQLITE_BUSY. The SQLite core only ever uses 6766** sqlite3_mutex_try() as an optimization so this is acceptable 6767** behavior.)^ 6768** 6769** ^The sqlite3_mutex_leave() routine exits a mutex that was 6770** previously entered by the same thread. The behavior 6771** is undefined if the mutex is not currently entered by the 6772** calling thread or is not currently allocated. 6773** 6774** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6775** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6776** behave as no-ops. 6777** 6778** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6779*/ 6780sqlite3_mutex *sqlite3_mutex_alloc(int); 6781void sqlite3_mutex_free(sqlite3_mutex*); 6782void sqlite3_mutex_enter(sqlite3_mutex*); 6783int sqlite3_mutex_try(sqlite3_mutex*); 6784void sqlite3_mutex_leave(sqlite3_mutex*); 6785 6786/* 6787** CAPI3REF: Mutex Methods Object 6788** 6789** An instance of this structure defines the low-level routines 6790** used to allocate and use mutexes. 6791** 6792** Usually, the default mutex implementations provided by SQLite are 6793** sufficient, however the application has the option of substituting a custom 6794** implementation for specialized deployments or systems for which SQLite 6795** does not provide a suitable implementation. In this case, the application 6796** creates and populates an instance of this structure to pass 6797** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6798** Additionally, an instance of this structure can be used as an 6799** output variable when querying the system for the current mutex 6800** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6801** 6802** ^The xMutexInit method defined by this structure is invoked as 6803** part of system initialization by the sqlite3_initialize() function. 6804** ^The xMutexInit routine is called by SQLite exactly once for each 6805** effective call to [sqlite3_initialize()]. 6806** 6807** ^The xMutexEnd method defined by this structure is invoked as 6808** part of system shutdown by the sqlite3_shutdown() function. The 6809** implementation of this method is expected to release all outstanding 6810** resources obtained by the mutex methods implementation, especially 6811** those obtained by the xMutexInit method. ^The xMutexEnd() 6812** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6813** 6814** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6815** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6816** xMutexNotheld) implement the following interfaces (respectively): 6817** 6818** <ul> 6819** <li> [sqlite3_mutex_alloc()] </li> 6820** <li> [sqlite3_mutex_free()] </li> 6821** <li> [sqlite3_mutex_enter()] </li> 6822** <li> [sqlite3_mutex_try()] </li> 6823** <li> [sqlite3_mutex_leave()] </li> 6824** <li> [sqlite3_mutex_held()] </li> 6825** <li> [sqlite3_mutex_notheld()] </li> 6826** </ul>)^ 6827** 6828** The only difference is that the public sqlite3_XXX functions enumerated 6829** above silently ignore any invocations that pass a NULL pointer instead 6830** of a valid mutex handle. The implementations of the methods defined 6831** by this structure are not required to handle this case, the results 6832** of passing a NULL pointer instead of a valid mutex handle are undefined 6833** (i.e. it is acceptable to provide an implementation that segfaults if 6834** it is passed a NULL pointer). 6835** 6836** The xMutexInit() method must be threadsafe. It must be harmless to 6837** invoke xMutexInit() multiple times within the same process and without 6838** intervening calls to xMutexEnd(). Second and subsequent calls to 6839** xMutexInit() must be no-ops. 6840** 6841** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6842** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6843** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6844** memory allocation for a fast or recursive mutex. 6845** 6846** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6847** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6848** If xMutexInit fails in any way, it is expected to clean up after itself 6849** prior to returning. 6850*/ 6851typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6852struct sqlite3_mutex_methods { 6853 int (*xMutexInit)(void); 6854 int (*xMutexEnd)(void); 6855 sqlite3_mutex *(*xMutexAlloc)(int); 6856 void (*xMutexFree)(sqlite3_mutex *); 6857 void (*xMutexEnter)(sqlite3_mutex *); 6858 int (*xMutexTry)(sqlite3_mutex *); 6859 void (*xMutexLeave)(sqlite3_mutex *); 6860 int (*xMutexHeld)(sqlite3_mutex *); 6861 int (*xMutexNotheld)(sqlite3_mutex *); 6862}; 6863 6864/* 6865** CAPI3REF: Mutex Verification Routines 6866** 6867** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6868** are intended for use inside assert() statements. The SQLite core 6869** never uses these routines except inside an assert() and applications 6870** are advised to follow the lead of the core. The SQLite core only 6871** provides implementations for these routines when it is compiled 6872** with the SQLITE_DEBUG flag. External mutex implementations 6873** are only required to provide these routines if SQLITE_DEBUG is 6874** defined and if NDEBUG is not defined. 6875** 6876** These routines should return true if the mutex in their argument 6877** is held or not held, respectively, by the calling thread. 6878** 6879** The implementation is not required to provide versions of these 6880** routines that actually work. If the implementation does not provide working 6881** versions of these routines, it should at least provide stubs that always 6882** return true so that one does not get spurious assertion failures. 6883** 6884** If the argument to sqlite3_mutex_held() is a NULL pointer then 6885** the routine should return 1. This seems counter-intuitive since 6886** clearly the mutex cannot be held if it does not exist. But 6887** the reason the mutex does not exist is because the build is not 6888** using mutexes. And we do not want the assert() containing the 6889** call to sqlite3_mutex_held() to fail, so a non-zero return is 6890** the appropriate thing to do. The sqlite3_mutex_notheld() 6891** interface should also return 1 when given a NULL pointer. 6892*/ 6893#ifndef NDEBUG 6894int sqlite3_mutex_held(sqlite3_mutex*); 6895int sqlite3_mutex_notheld(sqlite3_mutex*); 6896#endif 6897 6898/* 6899** CAPI3REF: Mutex Types 6900** 6901** The [sqlite3_mutex_alloc()] interface takes a single argument 6902** which is one of these integer constants. 6903** 6904** The set of static mutexes may change from one SQLite release to the 6905** next. Applications that override the built-in mutex logic must be 6906** prepared to accommodate additional static mutexes. 6907*/ 6908#define SQLITE_MUTEX_FAST 0 6909#define SQLITE_MUTEX_RECURSIVE 1 6910#define SQLITE_MUTEX_STATIC_MASTER 2 6911#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6912#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6913#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6914#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6915#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6916#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6917#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6918#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6919#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6920#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6921#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6922#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6923#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6924 6925/* 6926** CAPI3REF: Retrieve the mutex for a database connection 6927** METHOD: sqlite3 6928** 6929** ^This interface returns a pointer the [sqlite3_mutex] object that 6930** serializes access to the [database connection] given in the argument 6931** when the [threading mode] is Serialized. 6932** ^If the [threading mode] is Single-thread or Multi-thread then this 6933** routine returns a NULL pointer. 6934*/ 6935sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6936 6937/* 6938** CAPI3REF: Low-Level Control Of Database Files 6939** METHOD: sqlite3 6940** 6941** ^The [sqlite3_file_control()] interface makes a direct call to the 6942** xFileControl method for the [sqlite3_io_methods] object associated 6943** with a particular database identified by the second argument. ^The 6944** name of the database is "main" for the main database or "temp" for the 6945** TEMP database, or the name that appears after the AS keyword for 6946** databases that are added using the [ATTACH] SQL command. 6947** ^A NULL pointer can be used in place of "main" to refer to the 6948** main database file. 6949** ^The third and fourth parameters to this routine 6950** are passed directly through to the second and third parameters of 6951** the xFileControl method. ^The return value of the xFileControl 6952** method becomes the return value of this routine. 6953** 6954** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6955** a pointer to the underlying [sqlite3_file] object to be written into 6956** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6957** case is a short-circuit path which does not actually invoke the 6958** underlying sqlite3_io_methods.xFileControl method. 6959** 6960** ^If the second parameter (zDbName) does not match the name of any 6961** open database file, then SQLITE_ERROR is returned. ^This error 6962** code is not remembered and will not be recalled by [sqlite3_errcode()] 6963** or [sqlite3_errmsg()]. The underlying xFileControl method might 6964** also return SQLITE_ERROR. There is no way to distinguish between 6965** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6966** xFileControl method. 6967** 6968** See also: [SQLITE_FCNTL_LOCKSTATE] 6969*/ 6970int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6971 6972/* 6973** CAPI3REF: Testing Interface 6974** 6975** ^The sqlite3_test_control() interface is used to read out internal 6976** state of SQLite and to inject faults into SQLite for testing 6977** purposes. ^The first parameter is an operation code that determines 6978** the number, meaning, and operation of all subsequent parameters. 6979** 6980** This interface is not for use by applications. It exists solely 6981** for verifying the correct operation of the SQLite library. Depending 6982** on how the SQLite library is compiled, this interface might not exist. 6983** 6984** The details of the operation codes, their meanings, the parameters 6985** they take, and what they do are all subject to change without notice. 6986** Unlike most of the SQLite API, this function is not guaranteed to 6987** operate consistently from one release to the next. 6988*/ 6989int sqlite3_test_control(int op, ...); 6990 6991/* 6992** CAPI3REF: Testing Interface Operation Codes 6993** 6994** These constants are the valid operation code parameters used 6995** as the first argument to [sqlite3_test_control()]. 6996** 6997** These parameters and their meanings are subject to change 6998** without notice. These values are for testing purposes only. 6999** Applications should not use any of these parameters or the 7000** [sqlite3_test_control()] interface. 7001*/ 7002#define SQLITE_TESTCTRL_FIRST 5 7003#define SQLITE_TESTCTRL_PRNG_SAVE 5 7004#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7005#define SQLITE_TESTCTRL_PRNG_RESET 7 7006#define SQLITE_TESTCTRL_BITVEC_TEST 8 7007#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7008#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7009#define SQLITE_TESTCTRL_PENDING_BYTE 11 7010#define SQLITE_TESTCTRL_ASSERT 12 7011#define SQLITE_TESTCTRL_ALWAYS 13 7012#define SQLITE_TESTCTRL_RESERVE 14 7013#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7014#define SQLITE_TESTCTRL_ISKEYWORD 16 7015#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7016#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7017#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7018#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7019#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7020#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7021#define SQLITE_TESTCTRL_BYTEORDER 22 7022#define SQLITE_TESTCTRL_ISINIT 23 7023#define SQLITE_TESTCTRL_SORTER_MMAP 24 7024#define SQLITE_TESTCTRL_IMPOSTER 25 7025#define SQLITE_TESTCTRL_LAST 25 7026 7027/* 7028** CAPI3REF: SQLite Runtime Status 7029** 7030** ^These interfaces are used to retrieve runtime status information 7031** about the performance of SQLite, and optionally to reset various 7032** highwater marks. ^The first argument is an integer code for 7033** the specific parameter to measure. ^(Recognized integer codes 7034** are of the form [status parameters | SQLITE_STATUS_...].)^ 7035** ^The current value of the parameter is returned into *pCurrent. 7036** ^The highest recorded value is returned in *pHighwater. ^If the 7037** resetFlag is true, then the highest record value is reset after 7038** *pHighwater is written. ^(Some parameters do not record the highest 7039** value. For those parameters 7040** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7041** ^(Other parameters record only the highwater mark and not the current 7042** value. For these latter parameters nothing is written into *pCurrent.)^ 7043** 7044** ^The sqlite3_status() and sqlite3_status64() routines return 7045** SQLITE_OK on success and a non-zero [error code] on failure. 7046** 7047** If either the current value or the highwater mark is too large to 7048** be represented by a 32-bit integer, then the values returned by 7049** sqlite3_status() are undefined. 7050** 7051** See also: [sqlite3_db_status()] 7052*/ 7053int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7054int sqlite3_status64( 7055 int op, 7056 sqlite3_int64 *pCurrent, 7057 sqlite3_int64 *pHighwater, 7058 int resetFlag 7059); 7060 7061 7062/* 7063** CAPI3REF: Status Parameters 7064** KEYWORDS: {status parameters} 7065** 7066** These integer constants designate various run-time status parameters 7067** that can be returned by [sqlite3_status()]. 7068** 7069** <dl> 7070** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7071** <dd>This parameter is the current amount of memory checked out 7072** using [sqlite3_malloc()], either directly or indirectly. The 7073** figure includes calls made to [sqlite3_malloc()] by the application 7074** and internal memory usage by the SQLite library. Auxiliary page-cache 7075** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7076** this parameter. The amount returned is the sum of the allocation 7077** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7078** 7079** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7080** <dd>This parameter records the largest memory allocation request 7081** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7082** internal equivalents). Only the value returned in the 7083** *pHighwater parameter to [sqlite3_status()] is of interest. 7084** The value written into the *pCurrent parameter is undefined.</dd>)^ 7085** 7086** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7087** <dd>This parameter records the number of separate memory allocations 7088** currently checked out.</dd>)^ 7089** 7090** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7091** <dd>This parameter returns the number of pages used out of the 7092** [pagecache memory allocator] that was configured using 7093** [SQLITE_CONFIG_PAGECACHE]. The 7094** value returned is in pages, not in bytes.</dd>)^ 7095** 7096** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7097** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7098** <dd>This parameter returns the number of bytes of page cache 7099** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7100** buffer and where forced to overflow to [sqlite3_malloc()]. The 7101** returned value includes allocations that overflowed because they 7102** where too large (they were larger than the "sz" parameter to 7103** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7104** no space was left in the page cache.</dd>)^ 7105** 7106** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7107** <dd>This parameter records the largest memory allocation request 7108** handed to [pagecache memory allocator]. Only the value returned in the 7109** *pHighwater parameter to [sqlite3_status()] is of interest. 7110** The value written into the *pCurrent parameter is undefined.</dd>)^ 7111** 7112** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7113** <dd>No longer used.</dd> 7114** 7115** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7116** <dd>No longer used.</dd> 7117** 7118** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7119** <dd>No longer used.</dd> 7120** 7121** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7122** <dd>The *pHighwater parameter records the deepest parser stack. 7123** The *pCurrent value is undefined. The *pHighwater value is only 7124** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7125** </dl> 7126** 7127** New status parameters may be added from time to time. 7128*/ 7129#define SQLITE_STATUS_MEMORY_USED 0 7130#define SQLITE_STATUS_PAGECACHE_USED 1 7131#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7132#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7133#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7134#define SQLITE_STATUS_MALLOC_SIZE 5 7135#define SQLITE_STATUS_PARSER_STACK 6 7136#define SQLITE_STATUS_PAGECACHE_SIZE 7 7137#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7138#define SQLITE_STATUS_MALLOC_COUNT 9 7139 7140/* 7141** CAPI3REF: Database Connection Status 7142** METHOD: sqlite3 7143** 7144** ^This interface is used to retrieve runtime status information 7145** about a single [database connection]. ^The first argument is the 7146** database connection object to be interrogated. ^The second argument 7147** is an integer constant, taken from the set of 7148** [SQLITE_DBSTATUS options], that 7149** determines the parameter to interrogate. The set of 7150** [SQLITE_DBSTATUS options] is likely 7151** to grow in future releases of SQLite. 7152** 7153** ^The current value of the requested parameter is written into *pCur 7154** and the highest instantaneous value is written into *pHiwtr. ^If 7155** the resetFlg is true, then the highest instantaneous value is 7156** reset back down to the current value. 7157** 7158** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7159** non-zero [error code] on failure. 7160** 7161** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7162*/ 7163int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7164 7165/* 7166** CAPI3REF: Status Parameters for database connections 7167** KEYWORDS: {SQLITE_DBSTATUS options} 7168** 7169** These constants are the available integer "verbs" that can be passed as 7170** the second argument to the [sqlite3_db_status()] interface. 7171** 7172** New verbs may be added in future releases of SQLite. Existing verbs 7173** might be discontinued. Applications should check the return code from 7174** [sqlite3_db_status()] to make sure that the call worked. 7175** The [sqlite3_db_status()] interface will return a non-zero error code 7176** if a discontinued or unsupported verb is invoked. 7177** 7178** <dl> 7179** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7180** <dd>This parameter returns the number of lookaside memory slots currently 7181** checked out.</dd>)^ 7182** 7183** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7184** <dd>This parameter returns the number malloc attempts that were 7185** satisfied using lookaside memory. Only the high-water value is meaningful; 7186** the current value is always zero.)^ 7187** 7188** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7189** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7190** <dd>This parameter returns the number malloc attempts that might have 7191** been satisfied using lookaside memory but failed due to the amount of 7192** memory requested being larger than the lookaside slot size. 7193** Only the high-water value is meaningful; 7194** the current value is always zero.)^ 7195** 7196** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7197** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7198** <dd>This parameter returns the number malloc attempts that might have 7199** been satisfied using lookaside memory but failed due to all lookaside 7200** memory already being in use. 7201** Only the high-water value is meaningful; 7202** the current value is always zero.)^ 7203** 7204** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7205** <dd>This parameter returns the approximate number of bytes of heap 7206** memory used by all pager caches associated with the database connection.)^ 7207** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7208** 7209** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7210** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7211** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7212** pager cache is shared between two or more connections the bytes of heap 7213** memory used by that pager cache is divided evenly between the attached 7214** connections.)^ In other words, if none of the pager caches associated 7215** with the database connection are shared, this request returns the same 7216** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7217** shared, the value returned by this call will be smaller than that returned 7218** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7219** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7220** 7221** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7222** <dd>This parameter returns the approximate number of bytes of heap 7223** memory used to store the schema for all databases associated 7224** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7225** ^The full amount of memory used by the schemas is reported, even if the 7226** schema memory is shared with other database connections due to 7227** [shared cache mode] being enabled. 7228** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7229** 7230** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7231** <dd>This parameter returns the approximate number of bytes of heap 7232** and lookaside memory used by all prepared statements associated with 7233** the database connection.)^ 7234** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7235** </dd> 7236** 7237** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7238** <dd>This parameter returns the number of pager cache hits that have 7239** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7240** is always 0. 7241** </dd> 7242** 7243** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7244** <dd>This parameter returns the number of pager cache misses that have 7245** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7246** is always 0. 7247** </dd> 7248** 7249** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7250** <dd>This parameter returns the number of dirty cache entries that have 7251** been written to disk. Specifically, the number of pages written to the 7252** wal file in wal mode databases, or the number of pages written to the 7253** database file in rollback mode databases. Any pages written as part of 7254** transaction rollback or database recovery operations are not included. 7255** If an IO or other error occurs while writing a page to disk, the effect 7256** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7257** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7258** </dd> 7259** 7260** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7261** <dd>This parameter returns zero for the current value if and only if 7262** all foreign key constraints (deferred or immediate) have been 7263** resolved.)^ ^The highwater mark is always 0. 7264** </dd> 7265** </dl> 7266*/ 7267#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7268#define SQLITE_DBSTATUS_CACHE_USED 1 7269#define SQLITE_DBSTATUS_SCHEMA_USED 2 7270#define SQLITE_DBSTATUS_STMT_USED 3 7271#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7272#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7273#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7274#define SQLITE_DBSTATUS_CACHE_HIT 7 7275#define SQLITE_DBSTATUS_CACHE_MISS 8 7276#define SQLITE_DBSTATUS_CACHE_WRITE 9 7277#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7278#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7279#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7280 7281 7282/* 7283** CAPI3REF: Prepared Statement Status 7284** METHOD: sqlite3_stmt 7285** 7286** ^(Each prepared statement maintains various 7287** [SQLITE_STMTSTATUS counters] that measure the number 7288** of times it has performed specific operations.)^ These counters can 7289** be used to monitor the performance characteristics of the prepared 7290** statements. For example, if the number of table steps greatly exceeds 7291** the number of table searches or result rows, that would tend to indicate 7292** that the prepared statement is using a full table scan rather than 7293** an index. 7294** 7295** ^(This interface is used to retrieve and reset counter values from 7296** a [prepared statement]. The first argument is the prepared statement 7297** object to be interrogated. The second argument 7298** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7299** to be interrogated.)^ 7300** ^The current value of the requested counter is returned. 7301** ^If the resetFlg is true, then the counter is reset to zero after this 7302** interface call returns. 7303** 7304** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7305*/ 7306int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7307 7308/* 7309** CAPI3REF: Status Parameters for prepared statements 7310** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7311** 7312** These preprocessor macros define integer codes that name counter 7313** values associated with the [sqlite3_stmt_status()] interface. 7314** The meanings of the various counters are as follows: 7315** 7316** <dl> 7317** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7318** <dd>^This is the number of times that SQLite has stepped forward in 7319** a table as part of a full table scan. Large numbers for this counter 7320** may indicate opportunities for performance improvement through 7321** careful use of indices.</dd> 7322** 7323** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7324** <dd>^This is the number of sort operations that have occurred. 7325** A non-zero value in this counter may indicate an opportunity to 7326** improvement performance through careful use of indices.</dd> 7327** 7328** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7329** <dd>^This is the number of rows inserted into transient indices that 7330** were created automatically in order to help joins run faster. 7331** A non-zero value in this counter may indicate an opportunity to 7332** improvement performance by adding permanent indices that do not 7333** need to be reinitialized each time the statement is run.</dd> 7334** 7335** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7336** <dd>^This is the number of virtual machine operations executed 7337** by the prepared statement if that number is less than or equal 7338** to 2147483647. The number of virtual machine operations can be 7339** used as a proxy for the total work done by the prepared statement. 7340** If the number of virtual machine operations exceeds 2147483647 7341** then the value returned by this statement status code is undefined. 7342** 7343** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7344** <dd>^This is the number of times that the prepare statement has been 7345** automatically regenerated due to schema changes or change to 7346** [bound parameters] that might affect the query plan. 7347** 7348** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7349** <dd>^This is the number of times that the prepared statement has 7350** been run. A single "run" for the purposes of this counter is one 7351** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7352** The counter is incremented on the first [sqlite3_step()] call of each 7353** cycle. 7354** 7355** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7356** <dd>^This is the approximate number of bytes of heap memory 7357** used to store the prepared statement. ^This value is not actually 7358** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7359** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7360** </dd> 7361** </dl> 7362*/ 7363#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7364#define SQLITE_STMTSTATUS_SORT 2 7365#define SQLITE_STMTSTATUS_AUTOINDEX 3 7366#define SQLITE_STMTSTATUS_VM_STEP 4 7367#define SQLITE_STMTSTATUS_REPREPARE 5 7368#define SQLITE_STMTSTATUS_RUN 6 7369#define SQLITE_STMTSTATUS_MEMUSED 99 7370 7371/* 7372** CAPI3REF: Custom Page Cache Object 7373** 7374** The sqlite3_pcache type is opaque. It is implemented by 7375** the pluggable module. The SQLite core has no knowledge of 7376** its size or internal structure and never deals with the 7377** sqlite3_pcache object except by holding and passing pointers 7378** to the object. 7379** 7380** See [sqlite3_pcache_methods2] for additional information. 7381*/ 7382typedef struct sqlite3_pcache sqlite3_pcache; 7383 7384/* 7385** CAPI3REF: Custom Page Cache Object 7386** 7387** The sqlite3_pcache_page object represents a single page in the 7388** page cache. The page cache will allocate instances of this 7389** object. Various methods of the page cache use pointers to instances 7390** of this object as parameters or as their return value. 7391** 7392** See [sqlite3_pcache_methods2] for additional information. 7393*/ 7394typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7395struct sqlite3_pcache_page { 7396 void *pBuf; /* The content of the page */ 7397 void *pExtra; /* Extra information associated with the page */ 7398}; 7399 7400/* 7401** CAPI3REF: Application Defined Page Cache. 7402** KEYWORDS: {page cache} 7403** 7404** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7405** register an alternative page cache implementation by passing in an 7406** instance of the sqlite3_pcache_methods2 structure.)^ 7407** In many applications, most of the heap memory allocated by 7408** SQLite is used for the page cache. 7409** By implementing a 7410** custom page cache using this API, an application can better control 7411** the amount of memory consumed by SQLite, the way in which 7412** that memory is allocated and released, and the policies used to 7413** determine exactly which parts of a database file are cached and for 7414** how long. 7415** 7416** The alternative page cache mechanism is an 7417** extreme measure that is only needed by the most demanding applications. 7418** The built-in page cache is recommended for most uses. 7419** 7420** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7421** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7422** the application may discard the parameter after the call to 7423** [sqlite3_config()] returns.)^ 7424** 7425** [[the xInit() page cache method]] 7426** ^(The xInit() method is called once for each effective 7427** call to [sqlite3_initialize()])^ 7428** (usually only once during the lifetime of the process). ^(The xInit() 7429** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7430** The intent of the xInit() method is to set up global data structures 7431** required by the custom page cache implementation. 7432** ^(If the xInit() method is NULL, then the 7433** built-in default page cache is used instead of the application defined 7434** page cache.)^ 7435** 7436** [[the xShutdown() page cache method]] 7437** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7438** It can be used to clean up 7439** any outstanding resources before process shutdown, if required. 7440** ^The xShutdown() method may be NULL. 7441** 7442** ^SQLite automatically serializes calls to the xInit method, 7443** so the xInit method need not be threadsafe. ^The 7444** xShutdown method is only called from [sqlite3_shutdown()] so it does 7445** not need to be threadsafe either. All other methods must be threadsafe 7446** in multithreaded applications. 7447** 7448** ^SQLite will never invoke xInit() more than once without an intervening 7449** call to xShutdown(). 7450** 7451** [[the xCreate() page cache methods]] 7452** ^SQLite invokes the xCreate() method to construct a new cache instance. 7453** SQLite will typically create one cache instance for each open database file, 7454** though this is not guaranteed. ^The 7455** first parameter, szPage, is the size in bytes of the pages that must 7456** be allocated by the cache. ^szPage will always a power of two. ^The 7457** second parameter szExtra is a number of bytes of extra storage 7458** associated with each page cache entry. ^The szExtra parameter will 7459** a number less than 250. SQLite will use the 7460** extra szExtra bytes on each page to store metadata about the underlying 7461** database page on disk. The value passed into szExtra depends 7462** on the SQLite version, the target platform, and how SQLite was compiled. 7463** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7464** created will be used to cache database pages of a file stored on disk, or 7465** false if it is used for an in-memory database. The cache implementation 7466** does not have to do anything special based with the value of bPurgeable; 7467** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7468** never invoke xUnpin() except to deliberately delete a page. 7469** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7470** false will always have the "discard" flag set to true. 7471** ^Hence, a cache created with bPurgeable false will 7472** never contain any unpinned pages. 7473** 7474** [[the xCachesize() page cache method]] 7475** ^(The xCachesize() method may be called at any time by SQLite to set the 7476** suggested maximum cache-size (number of pages stored by) the cache 7477** instance passed as the first argument. This is the value configured using 7478** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7479** parameter, the implementation is not required to do anything with this 7480** value; it is advisory only. 7481** 7482** [[the xPagecount() page cache methods]] 7483** The xPagecount() method must return the number of pages currently 7484** stored in the cache, both pinned and unpinned. 7485** 7486** [[the xFetch() page cache methods]] 7487** The xFetch() method locates a page in the cache and returns a pointer to 7488** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7489** The pBuf element of the returned sqlite3_pcache_page object will be a 7490** pointer to a buffer of szPage bytes used to store the content of a 7491** single database page. The pExtra element of sqlite3_pcache_page will be 7492** a pointer to the szExtra bytes of extra storage that SQLite has requested 7493** for each entry in the page cache. 7494** 7495** The page to be fetched is determined by the key. ^The minimum key value 7496** is 1. After it has been retrieved using xFetch, the page is considered 7497** to be "pinned". 7498** 7499** If the requested page is already in the page cache, then the page cache 7500** implementation must return a pointer to the page buffer with its content 7501** intact. If the requested page is not already in the cache, then the 7502** cache implementation should use the value of the createFlag 7503** parameter to help it determined what action to take: 7504** 7505** <table border=1 width=85% align=center> 7506** <tr><th> createFlag <th> Behavior when page is not already in cache 7507** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7508** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7509** Otherwise return NULL. 7510** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7511** NULL if allocating a new page is effectively impossible. 7512** </table> 7513** 7514** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7515** will only use a createFlag of 2 after a prior call with a createFlag of 1 7516** failed.)^ In between the to xFetch() calls, SQLite may 7517** attempt to unpin one or more cache pages by spilling the content of 7518** pinned pages to disk and synching the operating system disk cache. 7519** 7520** [[the xUnpin() page cache method]] 7521** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7522** as its second argument. If the third parameter, discard, is non-zero, 7523** then the page must be evicted from the cache. 7524** ^If the discard parameter is 7525** zero, then the page may be discarded or retained at the discretion of 7526** page cache implementation. ^The page cache implementation 7527** may choose to evict unpinned pages at any time. 7528** 7529** The cache must not perform any reference counting. A single 7530** call to xUnpin() unpins the page regardless of the number of prior calls 7531** to xFetch(). 7532** 7533** [[the xRekey() page cache methods]] 7534** The xRekey() method is used to change the key value associated with the 7535** page passed as the second argument. If the cache 7536** previously contains an entry associated with newKey, it must be 7537** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7538** to be pinned. 7539** 7540** When SQLite calls the xTruncate() method, the cache must discard all 7541** existing cache entries with page numbers (keys) greater than or equal 7542** to the value of the iLimit parameter passed to xTruncate(). If any 7543** of these pages are pinned, they are implicitly unpinned, meaning that 7544** they can be safely discarded. 7545** 7546** [[the xDestroy() page cache method]] 7547** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7548** All resources associated with the specified cache should be freed. ^After 7549** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7550** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7551** functions. 7552** 7553** [[the xShrink() page cache method]] 7554** ^SQLite invokes the xShrink() method when it wants the page cache to 7555** free up as much of heap memory as possible. The page cache implementation 7556** is not obligated to free any memory, but well-behaved implementations should 7557** do their best. 7558*/ 7559typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7560struct sqlite3_pcache_methods2 { 7561 int iVersion; 7562 void *pArg; 7563 int (*xInit)(void*); 7564 void (*xShutdown)(void*); 7565 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7566 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7567 int (*xPagecount)(sqlite3_pcache*); 7568 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7569 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7570 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7571 unsigned oldKey, unsigned newKey); 7572 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7573 void (*xDestroy)(sqlite3_pcache*); 7574 void (*xShrink)(sqlite3_pcache*); 7575}; 7576 7577/* 7578** This is the obsolete pcache_methods object that has now been replaced 7579** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7580** retained in the header file for backwards compatibility only. 7581*/ 7582typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7583struct sqlite3_pcache_methods { 7584 void *pArg; 7585 int (*xInit)(void*); 7586 void (*xShutdown)(void*); 7587 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7588 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7589 int (*xPagecount)(sqlite3_pcache*); 7590 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7591 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7592 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7593 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7594 void (*xDestroy)(sqlite3_pcache*); 7595}; 7596 7597 7598/* 7599** CAPI3REF: Online Backup Object 7600** 7601** The sqlite3_backup object records state information about an ongoing 7602** online backup operation. ^The sqlite3_backup object is created by 7603** a call to [sqlite3_backup_init()] and is destroyed by a call to 7604** [sqlite3_backup_finish()]. 7605** 7606** See Also: [Using the SQLite Online Backup API] 7607*/ 7608typedef struct sqlite3_backup sqlite3_backup; 7609 7610/* 7611** CAPI3REF: Online Backup API. 7612** 7613** The backup API copies the content of one database into another. 7614** It is useful either for creating backups of databases or 7615** for copying in-memory databases to or from persistent files. 7616** 7617** See Also: [Using the SQLite Online Backup API] 7618** 7619** ^SQLite holds a write transaction open on the destination database file 7620** for the duration of the backup operation. 7621** ^The source database is read-locked only while it is being read; 7622** it is not locked continuously for the entire backup operation. 7623** ^Thus, the backup may be performed on a live source database without 7624** preventing other database connections from 7625** reading or writing to the source database while the backup is underway. 7626** 7627** ^(To perform a backup operation: 7628** <ol> 7629** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7630** backup, 7631** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7632** the data between the two databases, and finally 7633** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7634** associated with the backup operation. 7635** </ol>)^ 7636** There should be exactly one call to sqlite3_backup_finish() for each 7637** successful call to sqlite3_backup_init(). 7638** 7639** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7640** 7641** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7642** [database connection] associated with the destination database 7643** and the database name, respectively. 7644** ^The database name is "main" for the main database, "temp" for the 7645** temporary database, or the name specified after the AS keyword in 7646** an [ATTACH] statement for an attached database. 7647** ^The S and M arguments passed to 7648** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7649** and database name of the source database, respectively. 7650** ^The source and destination [database connections] (parameters S and D) 7651** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7652** an error. 7653** 7654** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7655** there is already a read or read-write transaction open on the 7656** destination database. 7657** 7658** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7659** returned and an error code and error message are stored in the 7660** destination [database connection] D. 7661** ^The error code and message for the failed call to sqlite3_backup_init() 7662** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7663** [sqlite3_errmsg16()] functions. 7664** ^A successful call to sqlite3_backup_init() returns a pointer to an 7665** [sqlite3_backup] object. 7666** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7667** sqlite3_backup_finish() functions to perform the specified backup 7668** operation. 7669** 7670** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7671** 7672** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7673** the source and destination databases specified by [sqlite3_backup] object B. 7674** ^If N is negative, all remaining source pages are copied. 7675** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7676** are still more pages to be copied, then the function returns [SQLITE_OK]. 7677** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7678** from source to destination, then it returns [SQLITE_DONE]. 7679** ^If an error occurs while running sqlite3_backup_step(B,N), 7680** then an [error code] is returned. ^As well as [SQLITE_OK] and 7681** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7682** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7683** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7684** 7685** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7686** <ol> 7687** <li> the destination database was opened read-only, or 7688** <li> the destination database is using write-ahead-log journaling 7689** and the destination and source page sizes differ, or 7690** <li> the destination database is an in-memory database and the 7691** destination and source page sizes differ. 7692** </ol>)^ 7693** 7694** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7695** the [sqlite3_busy_handler | busy-handler function] 7696** is invoked (if one is specified). ^If the 7697** busy-handler returns non-zero before the lock is available, then 7698** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7699** sqlite3_backup_step() can be retried later. ^If the source 7700** [database connection] 7701** is being used to write to the source database when sqlite3_backup_step() 7702** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7703** case the call to sqlite3_backup_step() can be retried later on. ^(If 7704** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7705** [SQLITE_READONLY] is returned, then 7706** there is no point in retrying the call to sqlite3_backup_step(). These 7707** errors are considered fatal.)^ The application must accept 7708** that the backup operation has failed and pass the backup operation handle 7709** to the sqlite3_backup_finish() to release associated resources. 7710** 7711** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7712** on the destination file. ^The exclusive lock is not released until either 7713** sqlite3_backup_finish() is called or the backup operation is complete 7714** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7715** sqlite3_backup_step() obtains a [shared lock] on the source database that 7716** lasts for the duration of the sqlite3_backup_step() call. 7717** ^Because the source database is not locked between calls to 7718** sqlite3_backup_step(), the source database may be modified mid-way 7719** through the backup process. ^If the source database is modified by an 7720** external process or via a database connection other than the one being 7721** used by the backup operation, then the backup will be automatically 7722** restarted by the next call to sqlite3_backup_step(). ^If the source 7723** database is modified by the using the same database connection as is used 7724** by the backup operation, then the backup database is automatically 7725** updated at the same time. 7726** 7727** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7728** 7729** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7730** application wishes to abandon the backup operation, the application 7731** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7732** ^The sqlite3_backup_finish() interfaces releases all 7733** resources associated with the [sqlite3_backup] object. 7734** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7735** active write-transaction on the destination database is rolled back. 7736** The [sqlite3_backup] object is invalid 7737** and may not be used following a call to sqlite3_backup_finish(). 7738** 7739** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7740** sqlite3_backup_step() errors occurred, regardless or whether or not 7741** sqlite3_backup_step() completed. 7742** ^If an out-of-memory condition or IO error occurred during any prior 7743** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7744** sqlite3_backup_finish() returns the corresponding [error code]. 7745** 7746** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7747** is not a permanent error and does not affect the return value of 7748** sqlite3_backup_finish(). 7749** 7750** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7751** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7752** 7753** ^The sqlite3_backup_remaining() routine returns the number of pages still 7754** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7755** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7756** in the source database at the conclusion of the most recent 7757** sqlite3_backup_step(). 7758** ^(The values returned by these functions are only updated by 7759** sqlite3_backup_step(). If the source database is modified in a way that 7760** changes the size of the source database or the number of pages remaining, 7761** those changes are not reflected in the output of sqlite3_backup_pagecount() 7762** and sqlite3_backup_remaining() until after the next 7763** sqlite3_backup_step().)^ 7764** 7765** <b>Concurrent Usage of Database Handles</b> 7766** 7767** ^The source [database connection] may be used by the application for other 7768** purposes while a backup operation is underway or being initialized. 7769** ^If SQLite is compiled and configured to support threadsafe database 7770** connections, then the source database connection may be used concurrently 7771** from within other threads. 7772** 7773** However, the application must guarantee that the destination 7774** [database connection] is not passed to any other API (by any thread) after 7775** sqlite3_backup_init() is called and before the corresponding call to 7776** sqlite3_backup_finish(). SQLite does not currently check to see 7777** if the application incorrectly accesses the destination [database connection] 7778** and so no error code is reported, but the operations may malfunction 7779** nevertheless. Use of the destination database connection while a 7780** backup is in progress might also also cause a mutex deadlock. 7781** 7782** If running in [shared cache mode], the application must 7783** guarantee that the shared cache used by the destination database 7784** is not accessed while the backup is running. In practice this means 7785** that the application must guarantee that the disk file being 7786** backed up to is not accessed by any connection within the process, 7787** not just the specific connection that was passed to sqlite3_backup_init(). 7788** 7789** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7790** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7791** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7792** APIs are not strictly speaking threadsafe. If they are invoked at the 7793** same time as another thread is invoking sqlite3_backup_step() it is 7794** possible that they return invalid values. 7795*/ 7796sqlite3_backup *sqlite3_backup_init( 7797 sqlite3 *pDest, /* Destination database handle */ 7798 const char *zDestName, /* Destination database name */ 7799 sqlite3 *pSource, /* Source database handle */ 7800 const char *zSourceName /* Source database name */ 7801); 7802int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7803int sqlite3_backup_finish(sqlite3_backup *p); 7804int sqlite3_backup_remaining(sqlite3_backup *p); 7805int sqlite3_backup_pagecount(sqlite3_backup *p); 7806 7807/* 7808** CAPI3REF: Unlock Notification 7809** METHOD: sqlite3 7810** 7811** ^When running in shared-cache mode, a database operation may fail with 7812** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7813** individual tables within the shared-cache cannot be obtained. See 7814** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7815** ^This API may be used to register a callback that SQLite will invoke 7816** when the connection currently holding the required lock relinquishes it. 7817** ^This API is only available if the library was compiled with the 7818** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7819** 7820** See Also: [Using the SQLite Unlock Notification Feature]. 7821** 7822** ^Shared-cache locks are released when a database connection concludes 7823** its current transaction, either by committing it or rolling it back. 7824** 7825** ^When a connection (known as the blocked connection) fails to obtain a 7826** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7827** identity of the database connection (the blocking connection) that 7828** has locked the required resource is stored internally. ^After an 7829** application receives an SQLITE_LOCKED error, it may call the 7830** sqlite3_unlock_notify() method with the blocked connection handle as 7831** the first argument to register for a callback that will be invoked 7832** when the blocking connections current transaction is concluded. ^The 7833** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7834** call that concludes the blocking connections transaction. 7835** 7836** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7837** there is a chance that the blocking connection will have already 7838** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7839** If this happens, then the specified callback is invoked immediately, 7840** from within the call to sqlite3_unlock_notify().)^ 7841** 7842** ^If the blocked connection is attempting to obtain a write-lock on a 7843** shared-cache table, and more than one other connection currently holds 7844** a read-lock on the same table, then SQLite arbitrarily selects one of 7845** the other connections to use as the blocking connection. 7846** 7847** ^(There may be at most one unlock-notify callback registered by a 7848** blocked connection. If sqlite3_unlock_notify() is called when the 7849** blocked connection already has a registered unlock-notify callback, 7850** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7851** called with a NULL pointer as its second argument, then any existing 7852** unlock-notify callback is canceled. ^The blocked connections 7853** unlock-notify callback may also be canceled by closing the blocked 7854** connection using [sqlite3_close()]. 7855** 7856** The unlock-notify callback is not reentrant. If an application invokes 7857** any sqlite3_xxx API functions from within an unlock-notify callback, a 7858** crash or deadlock may be the result. 7859** 7860** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7861** returns SQLITE_OK. 7862** 7863** <b>Callback Invocation Details</b> 7864** 7865** When an unlock-notify callback is registered, the application provides a 7866** single void* pointer that is passed to the callback when it is invoked. 7867** However, the signature of the callback function allows SQLite to pass 7868** it an array of void* context pointers. The first argument passed to 7869** an unlock-notify callback is a pointer to an array of void* pointers, 7870** and the second is the number of entries in the array. 7871** 7872** When a blocking connections transaction is concluded, there may be 7873** more than one blocked connection that has registered for an unlock-notify 7874** callback. ^If two or more such blocked connections have specified the 7875** same callback function, then instead of invoking the callback function 7876** multiple times, it is invoked once with the set of void* context pointers 7877** specified by the blocked connections bundled together into an array. 7878** This gives the application an opportunity to prioritize any actions 7879** related to the set of unblocked database connections. 7880** 7881** <b>Deadlock Detection</b> 7882** 7883** Assuming that after registering for an unlock-notify callback a 7884** database waits for the callback to be issued before taking any further 7885** action (a reasonable assumption), then using this API may cause the 7886** application to deadlock. For example, if connection X is waiting for 7887** connection Y's transaction to be concluded, and similarly connection 7888** Y is waiting on connection X's transaction, then neither connection 7889** will proceed and the system may remain deadlocked indefinitely. 7890** 7891** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7892** detection. ^If a given call to sqlite3_unlock_notify() would put the 7893** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7894** unlock-notify callback is registered. The system is said to be in 7895** a deadlocked state if connection A has registered for an unlock-notify 7896** callback on the conclusion of connection B's transaction, and connection 7897** B has itself registered for an unlock-notify callback when connection 7898** A's transaction is concluded. ^Indirect deadlock is also detected, so 7899** the system is also considered to be deadlocked if connection B has 7900** registered for an unlock-notify callback on the conclusion of connection 7901** C's transaction, where connection C is waiting on connection A. ^Any 7902** number of levels of indirection are allowed. 7903** 7904** <b>The "DROP TABLE" Exception</b> 7905** 7906** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7907** always appropriate to call sqlite3_unlock_notify(). There is however, 7908** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7909** SQLite checks if there are any currently executing SELECT statements 7910** that belong to the same connection. If there are, SQLITE_LOCKED is 7911** returned. In this case there is no "blocking connection", so invoking 7912** sqlite3_unlock_notify() results in the unlock-notify callback being 7913** invoked immediately. If the application then re-attempts the "DROP TABLE" 7914** or "DROP INDEX" query, an infinite loop might be the result. 7915** 7916** One way around this problem is to check the extended error code returned 7917** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7918** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7919** the special "DROP TABLE/INDEX" case, the extended error code is just 7920** SQLITE_LOCKED.)^ 7921*/ 7922int sqlite3_unlock_notify( 7923 sqlite3 *pBlocked, /* Waiting connection */ 7924 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7925 void *pNotifyArg /* Argument to pass to xNotify */ 7926); 7927 7928 7929/* 7930** CAPI3REF: String Comparison 7931** 7932** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7933** and extensions to compare the contents of two buffers containing UTF-8 7934** strings in a case-independent fashion, using the same definition of "case 7935** independence" that SQLite uses internally when comparing identifiers. 7936*/ 7937int sqlite3_stricmp(const char *, const char *); 7938int sqlite3_strnicmp(const char *, const char *, int); 7939 7940/* 7941** CAPI3REF: String Globbing 7942* 7943** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7944** string X matches the [GLOB] pattern P. 7945** ^The definition of [GLOB] pattern matching used in 7946** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7947** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7948** is case sensitive. 7949** 7950** Note that this routine returns zero on a match and non-zero if the strings 7951** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7952** 7953** See also: [sqlite3_strlike()]. 7954*/ 7955int sqlite3_strglob(const char *zGlob, const char *zStr); 7956 7957/* 7958** CAPI3REF: String LIKE Matching 7959* 7960** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7961** string X matches the [LIKE] pattern P with escape character E. 7962** ^The definition of [LIKE] pattern matching used in 7963** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7964** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7965** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7966** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7967** insensitive - equivalent upper and lower case ASCII characters match 7968** one another. 7969** 7970** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7971** only ASCII characters are case folded. 7972** 7973** Note that this routine returns zero on a match and non-zero if the strings 7974** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7975** 7976** See also: [sqlite3_strglob()]. 7977*/ 7978int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7979 7980/* 7981** CAPI3REF: Error Logging Interface 7982** 7983** ^The [sqlite3_log()] interface writes a message into the [error log] 7984** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7985** ^If logging is enabled, the zFormat string and subsequent arguments are 7986** used with [sqlite3_snprintf()] to generate the final output string. 7987** 7988** The sqlite3_log() interface is intended for use by extensions such as 7989** virtual tables, collating functions, and SQL functions. While there is 7990** nothing to prevent an application from calling sqlite3_log(), doing so 7991** is considered bad form. 7992** 7993** The zFormat string must not be NULL. 7994** 7995** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7996** will not use dynamically allocated memory. The log message is stored in 7997** a fixed-length buffer on the stack. If the log message is longer than 7998** a few hundred characters, it will be truncated to the length of the 7999** buffer. 8000*/ 8001void sqlite3_log(int iErrCode, const char *zFormat, ...); 8002 8003/* 8004** CAPI3REF: Write-Ahead Log Commit Hook 8005** METHOD: sqlite3 8006** 8007** ^The [sqlite3_wal_hook()] function is used to register a callback that 8008** is invoked each time data is committed to a database in wal mode. 8009** 8010** ^(The callback is invoked by SQLite after the commit has taken place and 8011** the associated write-lock on the database released)^, so the implementation 8012** may read, write or [checkpoint] the database as required. 8013** 8014** ^The first parameter passed to the callback function when it is invoked 8015** is a copy of the third parameter passed to sqlite3_wal_hook() when 8016** registering the callback. ^The second is a copy of the database handle. 8017** ^The third parameter is the name of the database that was written to - 8018** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8019** is the number of pages currently in the write-ahead log file, 8020** including those that were just committed. 8021** 8022** The callback function should normally return [SQLITE_OK]. ^If an error 8023** code is returned, that error will propagate back up through the 8024** SQLite code base to cause the statement that provoked the callback 8025** to report an error, though the commit will have still occurred. If the 8026** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8027** that does not correspond to any valid SQLite error code, the results 8028** are undefined. 8029** 8030** A single database handle may have at most a single write-ahead log callback 8031** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8032** previously registered write-ahead log callback. ^Note that the 8033** [sqlite3_wal_autocheckpoint()] interface and the 8034** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8035** overwrite any prior [sqlite3_wal_hook()] settings. 8036*/ 8037void *sqlite3_wal_hook( 8038 sqlite3*, 8039 int(*)(void *,sqlite3*,const char*,int), 8040 void* 8041); 8042 8043/* 8044** CAPI3REF: Configure an auto-checkpoint 8045** METHOD: sqlite3 8046** 8047** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8048** [sqlite3_wal_hook()] that causes any database on [database connection] D 8049** to automatically [checkpoint] 8050** after committing a transaction if there are N or 8051** more frames in the [write-ahead log] file. ^Passing zero or 8052** a negative value as the nFrame parameter disables automatic 8053** checkpoints entirely. 8054** 8055** ^The callback registered by this function replaces any existing callback 8056** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8057** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8058** configured by this function. 8059** 8060** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8061** from SQL. 8062** 8063** ^Checkpoints initiated by this mechanism are 8064** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8065** 8066** ^Every new [database connection] defaults to having the auto-checkpoint 8067** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8068** pages. The use of this interface 8069** is only necessary if the default setting is found to be suboptimal 8070** for a particular application. 8071*/ 8072int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8073 8074/* 8075** CAPI3REF: Checkpoint a database 8076** METHOD: sqlite3 8077** 8078** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8079** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8080** 8081** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8082** [write-ahead log] for database X on [database connection] D to be 8083** transferred into the database file and for the write-ahead log to 8084** be reset. See the [checkpointing] documentation for addition 8085** information. 8086** 8087** This interface used to be the only way to cause a checkpoint to 8088** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8089** interface was added. This interface is retained for backwards 8090** compatibility and as a convenience for applications that need to manually 8091** start a callback but which do not need the full power (and corresponding 8092** complication) of [sqlite3_wal_checkpoint_v2()]. 8093*/ 8094int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8095 8096/* 8097** CAPI3REF: Checkpoint a database 8098** METHOD: sqlite3 8099** 8100** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8101** operation on database X of [database connection] D in mode M. Status 8102** information is written back into integers pointed to by L and C.)^ 8103** ^(The M parameter must be a valid [checkpoint mode]:)^ 8104** 8105** <dl> 8106** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8107** ^Checkpoint as many frames as possible without waiting for any database 8108** readers or writers to finish, then sync the database file if all frames 8109** in the log were checkpointed. ^The [busy-handler callback] 8110** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8111** ^On the other hand, passive mode might leave the checkpoint unfinished 8112** if there are concurrent readers or writers. 8113** 8114** <dt>SQLITE_CHECKPOINT_FULL<dd> 8115** ^This mode blocks (it invokes the 8116** [sqlite3_busy_handler|busy-handler callback]) until there is no 8117** database writer and all readers are reading from the most recent database 8118** snapshot. ^It then checkpoints all frames in the log file and syncs the 8119** database file. ^This mode blocks new database writers while it is pending, 8120** but new database readers are allowed to continue unimpeded. 8121** 8122** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8123** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8124** that after checkpointing the log file it blocks (calls the 8125** [busy-handler callback]) 8126** until all readers are reading from the database file only. ^This ensures 8127** that the next writer will restart the log file from the beginning. 8128** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8129** database writer attempts while it is pending, but does not impede readers. 8130** 8131** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8132** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8133** addition that it also truncates the log file to zero bytes just prior 8134** to a successful return. 8135** </dl> 8136** 8137** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8138** the log file or to -1 if the checkpoint could not run because 8139** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8140** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8141** log file (including any that were already checkpointed before the function 8142** was called) or to -1 if the checkpoint could not run due to an error or 8143** because the database is not in WAL mode. ^Note that upon successful 8144** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8145** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8146** 8147** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8148** any other process is running a checkpoint operation at the same time, the 8149** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8150** busy-handler configured, it will not be invoked in this case. 8151** 8152** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8153** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8154** obtained immediately, and a busy-handler is configured, it is invoked and 8155** the writer lock retried until either the busy-handler returns 0 or the lock 8156** is successfully obtained. ^The busy-handler is also invoked while waiting for 8157** database readers as described above. ^If the busy-handler returns 0 before 8158** the writer lock is obtained or while waiting for database readers, the 8159** checkpoint operation proceeds from that point in the same way as 8160** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8161** without blocking any further. ^SQLITE_BUSY is returned in this case. 8162** 8163** ^If parameter zDb is NULL or points to a zero length string, then the 8164** specified operation is attempted on all WAL databases [attached] to 8165** [database connection] db. In this case the 8166** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8167** an SQLITE_BUSY error is encountered when processing one or more of the 8168** attached WAL databases, the operation is still attempted on any remaining 8169** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8170** error occurs while processing an attached database, processing is abandoned 8171** and the error code is returned to the caller immediately. ^If no error 8172** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8173** databases, SQLITE_OK is returned. 8174** 8175** ^If database zDb is the name of an attached database that is not in WAL 8176** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8177** zDb is not NULL (or a zero length string) and is not the name of any 8178** attached database, SQLITE_ERROR is returned to the caller. 8179** 8180** ^Unless it returns SQLITE_MISUSE, 8181** the sqlite3_wal_checkpoint_v2() interface 8182** sets the error information that is queried by 8183** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8184** 8185** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8186** from SQL. 8187*/ 8188int sqlite3_wal_checkpoint_v2( 8189 sqlite3 *db, /* Database handle */ 8190 const char *zDb, /* Name of attached database (or NULL) */ 8191 int eMode, /* SQLITE_CHECKPOINT_* value */ 8192 int *pnLog, /* OUT: Size of WAL log in frames */ 8193 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8194); 8195 8196/* 8197** CAPI3REF: Checkpoint Mode Values 8198** KEYWORDS: {checkpoint mode} 8199** 8200** These constants define all valid values for the "checkpoint mode" passed 8201** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8202** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8203** meaning of each of these checkpoint modes. 8204*/ 8205#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8206#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8207#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8208#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8209 8210/* 8211** CAPI3REF: Virtual Table Interface Configuration 8212** 8213** This function may be called by either the [xConnect] or [xCreate] method 8214** of a [virtual table] implementation to configure 8215** various facets of the virtual table interface. 8216** 8217** If this interface is invoked outside the context of an xConnect or 8218** xCreate virtual table method then the behavior is undefined. 8219** 8220** At present, there is only one option that may be configured using 8221** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8222** may be added in the future. 8223*/ 8224int sqlite3_vtab_config(sqlite3*, int op, ...); 8225 8226/* 8227** CAPI3REF: Virtual Table Configuration Options 8228** 8229** These macros define the various options to the 8230** [sqlite3_vtab_config()] interface that [virtual table] implementations 8231** can use to customize and optimize their behavior. 8232** 8233** <dl> 8234** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8235** <dd>Calls of the form 8236** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8237** where X is an integer. If X is zero, then the [virtual table] whose 8238** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8239** support constraints. In this configuration (which is the default) if 8240** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8241** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8242** specified as part of the users SQL statement, regardless of the actual 8243** ON CONFLICT mode specified. 8244** 8245** If X is non-zero, then the virtual table implementation guarantees 8246** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8247** any modifications to internal or persistent data structures have been made. 8248** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8249** is able to roll back a statement or database transaction, and abandon 8250** or continue processing the current SQL statement as appropriate. 8251** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8252** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8253** had been ABORT. 8254** 8255** Virtual table implementations that are required to handle OR REPLACE 8256** must do so within the [xUpdate] method. If a call to the 8257** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8258** CONFLICT policy is REPLACE, the virtual table implementation should 8259** silently replace the appropriate rows within the xUpdate callback and 8260** return SQLITE_OK. Or, if this is not possible, it may return 8261** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8262** constraint handling. 8263** </dl> 8264*/ 8265#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8266 8267/* 8268** CAPI3REF: Determine The Virtual Table Conflict Policy 8269** 8270** This function may only be called from within a call to the [xUpdate] method 8271** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8272** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8273** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8274** of the SQL statement that triggered the call to the [xUpdate] method of the 8275** [virtual table]. 8276*/ 8277int sqlite3_vtab_on_conflict(sqlite3 *); 8278 8279/* 8280** CAPI3REF: Conflict resolution modes 8281** KEYWORDS: {conflict resolution mode} 8282** 8283** These constants are returned by [sqlite3_vtab_on_conflict()] to 8284** inform a [virtual table] implementation what the [ON CONFLICT] mode 8285** is for the SQL statement being evaluated. 8286** 8287** Note that the [SQLITE_IGNORE] constant is also used as a potential 8288** return value from the [sqlite3_set_authorizer()] callback and that 8289** [SQLITE_ABORT] is also a [result code]. 8290*/ 8291#define SQLITE_ROLLBACK 1 8292/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8293#define SQLITE_FAIL 3 8294/* #define SQLITE_ABORT 4 // Also an error code */ 8295#define SQLITE_REPLACE 5 8296 8297/* 8298** CAPI3REF: Prepared Statement Scan Status Opcodes 8299** KEYWORDS: {scanstatus options} 8300** 8301** The following constants can be used for the T parameter to the 8302** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8303** different metric for sqlite3_stmt_scanstatus() to return. 8304** 8305** When the value returned to V is a string, space to hold that string is 8306** managed by the prepared statement S and will be automatically freed when 8307** S is finalized. 8308** 8309** <dl> 8310** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8311** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8312** set to the total number of times that the X-th loop has run.</dd> 8313** 8314** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8315** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8316** to the total number of rows examined by all iterations of the X-th loop.</dd> 8317** 8318** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8319** <dd>^The "double" variable pointed to by the T parameter will be set to the 8320** query planner's estimate for the average number of rows output from each 8321** iteration of the X-th loop. If the query planner's estimates was accurate, 8322** then this value will approximate the quotient NVISIT/NLOOP and the 8323** product of this value for all prior loops with the same SELECTID will 8324** be the NLOOP value for the current loop. 8325** 8326** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8327** <dd>^The "const char *" variable pointed to by the T parameter will be set 8328** to a zero-terminated UTF-8 string containing the name of the index or table 8329** used for the X-th loop. 8330** 8331** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8332** <dd>^The "const char *" variable pointed to by the T parameter will be set 8333** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8334** description for the X-th loop. 8335** 8336** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8337** <dd>^The "int" variable pointed to by the T parameter will be set to the 8338** "select-id" for the X-th loop. The select-id identifies which query or 8339** subquery the loop is part of. The main query has a select-id of zero. 8340** The select-id is the same value as is output in the first column 8341** of an [EXPLAIN QUERY PLAN] query. 8342** </dl> 8343*/ 8344#define SQLITE_SCANSTAT_NLOOP 0 8345#define SQLITE_SCANSTAT_NVISIT 1 8346#define SQLITE_SCANSTAT_EST 2 8347#define SQLITE_SCANSTAT_NAME 3 8348#define SQLITE_SCANSTAT_EXPLAIN 4 8349#define SQLITE_SCANSTAT_SELECTID 5 8350 8351/* 8352** CAPI3REF: Prepared Statement Scan Status 8353** METHOD: sqlite3_stmt 8354** 8355** This interface returns information about the predicted and measured 8356** performance for pStmt. Advanced applications can use this 8357** interface to compare the predicted and the measured performance and 8358** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8359** 8360** Since this interface is expected to be rarely used, it is only 8361** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8362** compile-time option. 8363** 8364** The "iScanStatusOp" parameter determines which status information to return. 8365** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8366** of this interface is undefined. 8367** ^The requested measurement is written into a variable pointed to by 8368** the "pOut" parameter. 8369** Parameter "idx" identifies the specific loop to retrieve statistics for. 8370** Loops are numbered starting from zero. ^If idx is out of range - less than 8371** zero or greater than or equal to the total number of loops used to implement 8372** the statement - a non-zero value is returned and the variable that pOut 8373** points to is unchanged. 8374** 8375** ^Statistics might not be available for all loops in all statements. ^In cases 8376** where there exist loops with no available statistics, this function behaves 8377** as if the loop did not exist - it returns non-zero and leave the variable 8378** that pOut points to unchanged. 8379** 8380** See also: [sqlite3_stmt_scanstatus_reset()] 8381*/ 8382int sqlite3_stmt_scanstatus( 8383 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8384 int idx, /* Index of loop to report on */ 8385 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8386 void *pOut /* Result written here */ 8387); 8388 8389/* 8390** CAPI3REF: Zero Scan-Status Counters 8391** METHOD: sqlite3_stmt 8392** 8393** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8394** 8395** This API is only available if the library is built with pre-processor 8396** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8397*/ 8398void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8399 8400/* 8401** CAPI3REF: Flush caches to disk mid-transaction 8402** 8403** ^If a write-transaction is open on [database connection] D when the 8404** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8405** pages in the pager-cache that are not currently in use are written out 8406** to disk. A dirty page may be in use if a database cursor created by an 8407** active SQL statement is reading from it, or if it is page 1 of a database 8408** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8409** interface flushes caches for all schemas - "main", "temp", and 8410** any [attached] databases. 8411** 8412** ^If this function needs to obtain extra database locks before dirty pages 8413** can be flushed to disk, it does so. ^If those locks cannot be obtained 8414** immediately and there is a busy-handler callback configured, it is invoked 8415** in the usual manner. ^If the required lock still cannot be obtained, then 8416** the database is skipped and an attempt made to flush any dirty pages 8417** belonging to the next (if any) database. ^If any databases are skipped 8418** because locks cannot be obtained, but no other error occurs, this 8419** function returns SQLITE_BUSY. 8420** 8421** ^If any other error occurs while flushing dirty pages to disk (for 8422** example an IO error or out-of-memory condition), then processing is 8423** abandoned and an SQLite [error code] is returned to the caller immediately. 8424** 8425** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8426** 8427** ^This function does not set the database handle error code or message 8428** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8429*/ 8430int sqlite3_db_cacheflush(sqlite3*); 8431 8432/* 8433** CAPI3REF: The pre-update hook. 8434** 8435** ^These interfaces are only available if SQLite is compiled using the 8436** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8437** 8438** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8439** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8440** on a database table. 8441** ^At most one preupdate hook may be registered at a time on a single 8442** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8443** the previous setting. 8444** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8445** with a NULL pointer as the second parameter. 8446** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8447** the first parameter to callbacks. 8448** 8449** ^The preupdate hook only fires for changes to real database tables; the 8450** preupdate hook is not invoked for changes to [virtual tables] or to 8451** system tables like sqlite_master or sqlite_stat1. 8452** 8453** ^The second parameter to the preupdate callback is a pointer to 8454** the [database connection] that registered the preupdate hook. 8455** ^The third parameter to the preupdate callback is one of the constants 8456** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8457** kind of update operation that is about to occur. 8458** ^(The fourth parameter to the preupdate callback is the name of the 8459** database within the database connection that is being modified. This 8460** will be "main" for the main database or "temp" for TEMP tables or 8461** the name given after the AS keyword in the [ATTACH] statement for attached 8462** databases.)^ 8463** ^The fifth parameter to the preupdate callback is the name of the 8464** table that is being modified. 8465** 8466** For an UPDATE or DELETE operation on a [rowid table], the sixth 8467** parameter passed to the preupdate callback is the initial [rowid] of the 8468** row being modified or deleted. For an INSERT operation on a rowid table, 8469** or any operation on a WITHOUT ROWID table, the value of the sixth 8470** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8471** seventh parameter is the final rowid value of the row being inserted 8472** or updated. The value of the seventh parameter passed to the callback 8473** function is not defined for operations on WITHOUT ROWID tables, or for 8474** INSERT operations on rowid tables. 8475** 8476** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8477** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8478** provide additional information about a preupdate event. These routines 8479** may only be called from within a preupdate callback. Invoking any of 8480** these routines from outside of a preupdate callback or with a 8481** [database connection] pointer that is different from the one supplied 8482** to the preupdate callback results in undefined and probably undesirable 8483** behavior. 8484** 8485** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8486** in the row that is being inserted, updated, or deleted. 8487** 8488** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8489** a [protected sqlite3_value] that contains the value of the Nth column of 8490** the table row before it is updated. The N parameter must be between 0 8491** and one less than the number of columns or the behavior will be 8492** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8493** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8494** behavior is undefined. The [sqlite3_value] that P points to 8495** will be destroyed when the preupdate callback returns. 8496** 8497** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8498** a [protected sqlite3_value] that contains the value of the Nth column of 8499** the table row after it is updated. The N parameter must be between 0 8500** and one less than the number of columns or the behavior will be 8501** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8502** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8503** behavior is undefined. The [sqlite3_value] that P points to 8504** will be destroyed when the preupdate callback returns. 8505** 8506** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8507** callback was invoked as a result of a direct insert, update, or delete 8508** operation; or 1 for inserts, updates, or deletes invoked by top-level 8509** triggers; or 2 for changes resulting from triggers called by top-level 8510** triggers; and so forth. 8511** 8512** See also: [sqlite3_update_hook()] 8513*/ 8514#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8515void *sqlite3_preupdate_hook( 8516 sqlite3 *db, 8517 void(*xPreUpdate)( 8518 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8519 sqlite3 *db, /* Database handle */ 8520 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8521 char const *zDb, /* Database name */ 8522 char const *zName, /* Table name */ 8523 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8524 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8525 ), 8526 void* 8527); 8528int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8529int sqlite3_preupdate_count(sqlite3 *); 8530int sqlite3_preupdate_depth(sqlite3 *); 8531int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8532#endif 8533 8534/* 8535** CAPI3REF: Low-level system error code 8536** 8537** ^Attempt to return the underlying operating system error code or error 8538** number that caused the most recent I/O error or failure to open a file. 8539** The return value is OS-dependent. For example, on unix systems, after 8540** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8541** called to get back the underlying "errno" that caused the problem, such 8542** as ENOSPC, EAUTH, EISDIR, and so forth. 8543*/ 8544int sqlite3_system_errno(sqlite3*); 8545 8546/* 8547** CAPI3REF: Database Snapshot 8548** KEYWORDS: {snapshot} {sqlite3_snapshot} 8549** EXPERIMENTAL 8550** 8551** An instance of the snapshot object records the state of a [WAL mode] 8552** database for some specific point in history. 8553** 8554** In [WAL mode], multiple [database connections] that are open on the 8555** same database file can each be reading a different historical version 8556** of the database file. When a [database connection] begins a read 8557** transaction, that connection sees an unchanging copy of the database 8558** as it existed for the point in time when the transaction first started. 8559** Subsequent changes to the database from other connections are not seen 8560** by the reader until a new read transaction is started. 8561** 8562** The sqlite3_snapshot object records state information about an historical 8563** version of the database file so that it is possible to later open a new read 8564** transaction that sees that historical version of the database rather than 8565** the most recent version. 8566** 8567** The constructor for this object is [sqlite3_snapshot_get()]. The 8568** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8569** to an historical snapshot (if possible). The destructor for 8570** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8571*/ 8572typedef struct sqlite3_snapshot { 8573 unsigned char hidden[48]; 8574} sqlite3_snapshot; 8575 8576/* 8577** CAPI3REF: Record A Database Snapshot 8578** EXPERIMENTAL 8579** 8580** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8581** new [sqlite3_snapshot] object that records the current state of 8582** schema S in database connection D. ^On success, the 8583** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8584** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8585** If there is not already a read-transaction open on schema S when 8586** this function is called, one is opened automatically. 8587** 8588** The following must be true for this function to succeed. If any of 8589** the following statements are false when sqlite3_snapshot_get() is 8590** called, SQLITE_ERROR is returned. The final value of *P is undefined 8591** in this case. 8592** 8593** <ul> 8594** <li> The database handle must be in [autocommit mode]. 8595** 8596** <li> Schema S of [database connection] D must be a [WAL mode] database. 8597** 8598** <li> There must not be a write transaction open on schema S of database 8599** connection D. 8600** 8601** <li> One or more transactions must have been written to the current wal 8602** file since it was created on disk (by any connection). This means 8603** that a snapshot cannot be taken on a wal mode database with no wal 8604** file immediately after it is first opened. At least one transaction 8605** must be written to it first. 8606** </ul> 8607** 8608** This function may also return SQLITE_NOMEM. If it is called with the 8609** database handle in autocommit mode but fails for some other reason, 8610** whether or not a read transaction is opened on schema S is undefined. 8611** 8612** The [sqlite3_snapshot] object returned from a successful call to 8613** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8614** to avoid a memory leak. 8615** 8616** The [sqlite3_snapshot_get()] interface is only available when the 8617** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8618*/ 8619SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8620 sqlite3 *db, 8621 const char *zSchema, 8622 sqlite3_snapshot **ppSnapshot 8623); 8624 8625/* 8626** CAPI3REF: Start a read transaction on an historical snapshot 8627** EXPERIMENTAL 8628** 8629** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8630** read transaction for schema S of 8631** [database connection] D such that the read transaction 8632** refers to historical [snapshot] P, rather than the most 8633** recent change to the database. 8634** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8635** or an appropriate [error code] if it fails. 8636** 8637** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8638** the first operation following the [BEGIN] that takes the schema S 8639** out of [autocommit mode]. 8640** ^In other words, schema S must not currently be in 8641** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8642** database connection D must be out of [autocommit mode]. 8643** ^A [snapshot] will fail to open if it has been overwritten by a 8644** [checkpoint]. 8645** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8646** database connection D does not know that the database file for 8647** schema S is in [WAL mode]. A database connection might not know 8648** that the database file is in [WAL mode] if there has been no prior 8649** I/O on that database connection, or if the database entered [WAL mode] 8650** after the most recent I/O on the database connection.)^ 8651** (Hint: Run "[PRAGMA application_id]" against a newly opened 8652** database connection in order to make it ready to use snapshots.) 8653** 8654** The [sqlite3_snapshot_open()] interface is only available when the 8655** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8656*/ 8657SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8658 sqlite3 *db, 8659 const char *zSchema, 8660 sqlite3_snapshot *pSnapshot 8661); 8662 8663/* 8664** CAPI3REF: Destroy a snapshot 8665** EXPERIMENTAL 8666** 8667** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8668** The application must eventually free every [sqlite3_snapshot] object 8669** using this routine to avoid a memory leak. 8670** 8671** The [sqlite3_snapshot_free()] interface is only available when the 8672** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8673*/ 8674SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8675 8676/* 8677** CAPI3REF: Compare the ages of two snapshot handles. 8678** EXPERIMENTAL 8679** 8680** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8681** of two valid snapshot handles. 8682** 8683** If the two snapshot handles are not associated with the same database 8684** file, the result of the comparison is undefined. 8685** 8686** Additionally, the result of the comparison is only valid if both of the 8687** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8688** last time the wal file was deleted. The wal file is deleted when the 8689** database is changed back to rollback mode or when the number of database 8690** clients drops to zero. If either snapshot handle was obtained before the 8691** wal file was last deleted, the value returned by this function 8692** is undefined. 8693** 8694** Otherwise, this API returns a negative value if P1 refers to an older 8695** snapshot than P2, zero if the two handles refer to the same database 8696** snapshot, and a positive value if P1 is a newer snapshot than P2. 8697*/ 8698SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8699 sqlite3_snapshot *p1, 8700 sqlite3_snapshot *p2 8701); 8702 8703/* 8704** CAPI3REF: Recover snapshots from a wal file 8705** EXPERIMENTAL 8706** 8707** If all connections disconnect from a database file but do not perform 8708** a checkpoint, the existing wal file is opened along with the database 8709** file the next time the database is opened. At this point it is only 8710** possible to successfully call sqlite3_snapshot_open() to open the most 8711** recent snapshot of the database (the one at the head of the wal file), 8712** even though the wal file may contain other valid snapshots for which 8713** clients have sqlite3_snapshot handles. 8714** 8715** This function attempts to scan the wal file associated with database zDb 8716** of database handle db and make all valid snapshots available to 8717** sqlite3_snapshot_open(). It is an error if there is already a read 8718** transaction open on the database, or if the database is not a wal mode 8719** database. 8720** 8721** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8722*/ 8723SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8724 8725/* 8726** Undo the hack that converts floating point types to integer for 8727** builds on processors without floating point support. 8728*/ 8729#ifdef SQLITE_OMIT_FLOATING_POINT 8730# undef double 8731#endif 8732 8733#ifdef __cplusplus 8734} /* End of the 'extern "C"' block */ 8735#endif 8736#endif /* SQLITE3_H */ 8737