1/* 2** 2001 September 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 an SHA1 118** hash of the entire source tree. 119** 120** See also: [sqlite3_libversion()], 121** [sqlite3_libversion_number()], [sqlite3_sourceid()], 122** [sqlite_version()] and [sqlite_source_id()]. 123*/ 124#define SQLITE_VERSION "--VERS--" 125#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 126#define SQLITE_SOURCE_ID "--SOURCE-ID--" 127 128/* 129** CAPI3REF: Run-Time Library Version Numbers 130** KEYWORDS: sqlite3_version, sqlite3_sourceid 131** 132** These interfaces provide the same information as the [SQLITE_VERSION], 133** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 134** but are associated with the library instead of the header file. ^(Cautious 135** programmers might include assert() statements in their application to 136** verify that values returned by these interfaces match the macros in 137** the header, and thus ensure that the application is 138** compiled with matching library and header files. 139** 140** <blockquote><pre> 141** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 142** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 143** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 144** </pre></blockquote>)^ 145** 146** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 147** macro. ^The sqlite3_libversion() function returns a pointer to the 148** to the sqlite3_version[] string constant. The sqlite3_libversion() 149** function is provided for use in DLLs since DLL users usually do not have 150** direct access to string constants within the DLL. ^The 151** sqlite3_libversion_number() function returns an integer equal to 152** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 153** a pointer to a string constant whose value is the same as the 154** [SQLITE_SOURCE_ID] C preprocessor macro. 155** 156** See also: [sqlite_version()] and [sqlite_source_id()]. 157*/ 158SQLITE_EXTERN const char sqlite3_version[]; 159const char *sqlite3_libversion(void); 160const char *sqlite3_sourceid(void); 161int sqlite3_libversion_number(void); 162 163/* 164** CAPI3REF: Run-Time Library Compilation Options Diagnostics 165** 166** ^The sqlite3_compileoption_used() function returns 0 or 1 167** indicating whether the specified option was defined at 168** compile time. ^The SQLITE_ prefix may be omitted from the 169** option name passed to sqlite3_compileoption_used(). 170** 171** ^The sqlite3_compileoption_get() function allows iterating 172** over the list of options that were defined at compile time by 173** returning the N-th compile time option string. ^If N is out of range, 174** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 175** prefix is omitted from any strings returned by 176** sqlite3_compileoption_get(). 177** 178** ^Support for the diagnostic functions sqlite3_compileoption_used() 179** and sqlite3_compileoption_get() may be omitted by specifying the 180** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 181** 182** See also: SQL functions [sqlite_compileoption_used()] and 183** [sqlite_compileoption_get()] and the [compile_options pragma]. 184*/ 185#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 186int sqlite3_compileoption_used(const char *zOptName); 187const char *sqlite3_compileoption_get(int N); 188#endif 189 190/* 191** CAPI3REF: Test To See If The Library Is Threadsafe 192** 193** ^The sqlite3_threadsafe() function returns zero if and only if 194** SQLite was compiled with mutexing code omitted due to the 195** [SQLITE_THREADSAFE] compile-time option being set to 0. 196** 197** SQLite can be compiled with or without mutexes. When 198** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 199** are enabled and SQLite is threadsafe. When the 200** [SQLITE_THREADSAFE] macro is 0, 201** the mutexes are omitted. Without the mutexes, it is not safe 202** to use SQLite concurrently from more than one thread. 203** 204** Enabling mutexes incurs a measurable performance penalty. 205** So if speed is of utmost importance, it makes sense to disable 206** the mutexes. But for maximum safety, mutexes should be enabled. 207** ^The default behavior is for mutexes to be enabled. 208** 209** This interface can be used by an application to make sure that the 210** version of SQLite that it is linking against was compiled with 211** the desired setting of the [SQLITE_THREADSAFE] macro. 212** 213** This interface only reports on the compile-time mutex setting 214** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 215** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 216** can be fully or partially disabled using a call to [sqlite3_config()] 217** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 218** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 219** sqlite3_threadsafe() function shows only the compile-time setting of 220** thread safety, not any run-time changes to that setting made by 221** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 222** is unchanged by calls to sqlite3_config().)^ 223** 224** See the [threading mode] documentation for additional information. 225*/ 226int sqlite3_threadsafe(void); 227 228/* 229** CAPI3REF: Database Connection Handle 230** KEYWORDS: {database connection} {database connections} 231** 232** Each open SQLite database is represented by a pointer to an instance of 233** the opaque structure named "sqlite3". It is useful to think of an sqlite3 234** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 235** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 236** and [sqlite3_close_v2()] are its destructors. There are many other 237** interfaces (such as 238** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 239** [sqlite3_busy_timeout()] to name but three) that are methods on an 240** sqlite3 object. 241*/ 242typedef struct sqlite3 sqlite3; 243 244/* 245** CAPI3REF: 64-Bit Integer Types 246** KEYWORDS: sqlite_int64 sqlite_uint64 247** 248** Because there is no cross-platform way to specify 64-bit integer types 249** SQLite includes typedefs for 64-bit signed and unsigned integers. 250** 251** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 252** The sqlite_int64 and sqlite_uint64 types are supported for backwards 253** compatibility only. 254** 255** ^The sqlite3_int64 and sqlite_int64 types can store integer values 256** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 257** sqlite3_uint64 and sqlite_uint64 types can store integer values 258** between 0 and +18446744073709551615 inclusive. 259*/ 260#ifdef SQLITE_INT64_TYPE 261 typedef SQLITE_INT64_TYPE sqlite_int64; 262 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 263#elif defined(_MSC_VER) || defined(__BORLANDC__) 264 typedef __int64 sqlite_int64; 265 typedef unsigned __int64 sqlite_uint64; 266#else 267 typedef long long int sqlite_int64; 268 typedef unsigned long long int sqlite_uint64; 269#endif 270typedef sqlite_int64 sqlite3_int64; 271typedef sqlite_uint64 sqlite3_uint64; 272 273/* 274** If compiling for a processor that lacks floating point support, 275** substitute integer for floating-point. 276*/ 277#ifdef SQLITE_OMIT_FLOATING_POINT 278# define double sqlite3_int64 279#endif 280 281/* 282** CAPI3REF: Closing A Database Connection 283** DESTRUCTOR: sqlite3 284** 285** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 286** for the [sqlite3] object. 287** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 288** the [sqlite3] object is successfully destroyed and all associated 289** resources are deallocated. 290** 291** ^If the database connection is associated with unfinalized prepared 292** statements or unfinished sqlite3_backup objects then sqlite3_close() 293** will leave the database connection open and return [SQLITE_BUSY]. 294** ^If sqlite3_close_v2() is called with unfinalized prepared statements 295** and/or unfinished sqlite3_backups, then the database connection becomes 296** an unusable "zombie" which will automatically be deallocated when the 297** last prepared statement is finalized or the last sqlite3_backup is 298** finished. The sqlite3_close_v2() interface is intended for use with 299** host languages that are garbage collected, and where the order in which 300** destructors are called is arbitrary. 301** 302** Applications should [sqlite3_finalize | finalize] all [prepared statements], 303** [sqlite3_blob_close | close] all [BLOB handles], and 304** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 305** with the [sqlite3] object prior to attempting to close the object. ^If 306** sqlite3_close_v2() is called on a [database connection] that still has 307** outstanding [prepared statements], [BLOB handles], and/or 308** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 309** of resources is deferred until all [prepared statements], [BLOB handles], 310** and [sqlite3_backup] objects are also destroyed. 311** 312** ^If an [sqlite3] object is destroyed while a transaction is open, 313** the transaction is automatically rolled back. 314** 315** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 316** must be either a NULL 317** pointer or an [sqlite3] object pointer obtained 318** from [sqlite3_open()], [sqlite3_open16()], or 319** [sqlite3_open_v2()], and not previously closed. 320** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 321** argument is a harmless no-op. 322*/ 323int sqlite3_close(sqlite3*); 324int sqlite3_close_v2(sqlite3*); 325 326/* 327** The type for a callback function. 328** This is legacy and deprecated. It is included for historical 329** compatibility and is not documented. 330*/ 331typedef int (*sqlite3_callback)(void*,int,char**, char**); 332 333/* 334** CAPI3REF: One-Step Query Execution Interface 335** METHOD: sqlite3 336** 337** The sqlite3_exec() interface is a convenience wrapper around 338** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 339** that allows an application to run multiple statements of SQL 340** without having to use a lot of C code. 341** 342** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 343** semicolon-separate SQL statements passed into its 2nd argument, 344** in the context of the [database connection] passed in as its 1st 345** argument. ^If the callback function of the 3rd argument to 346** sqlite3_exec() is not NULL, then it is invoked for each result row 347** coming out of the evaluated SQL statements. ^The 4th argument to 348** sqlite3_exec() is relayed through to the 1st argument of each 349** callback invocation. ^If the callback pointer to sqlite3_exec() 350** is NULL, then no callback is ever invoked and result rows are 351** ignored. 352** 353** ^If an error occurs while evaluating the SQL statements passed into 354** sqlite3_exec(), then execution of the current statement stops and 355** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 356** is not NULL then any error message is written into memory obtained 357** from [sqlite3_malloc()] and passed back through the 5th parameter. 358** To avoid memory leaks, the application should invoke [sqlite3_free()] 359** on error message strings returned through the 5th parameter of 360** sqlite3_exec() after the error message string is no longer needed. 361** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 362** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 363** NULL before returning. 364** 365** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 366** routine returns SQLITE_ABORT without invoking the callback again and 367** without running any subsequent SQL statements. 368** 369** ^The 2nd argument to the sqlite3_exec() callback function is the 370** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 371** callback is an array of pointers to strings obtained as if from 372** [sqlite3_column_text()], one for each column. ^If an element of a 373** result row is NULL then the corresponding string pointer for the 374** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 375** sqlite3_exec() callback is an array of pointers to strings where each 376** entry represents the name of corresponding result column as obtained 377** from [sqlite3_column_name()]. 378** 379** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 380** to an empty string, or a pointer that contains only whitespace and/or 381** SQL comments, then no SQL statements are evaluated and the database 382** is not changed. 383** 384** Restrictions: 385** 386** <ul> 387** <li> The application must ensure that the 1st parameter to sqlite3_exec() 388** is a valid and open [database connection]. 389** <li> The application must not close the [database connection] specified by 390** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 391** <li> The application must not modify the SQL statement text passed into 392** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 393** </ul> 394*/ 395int sqlite3_exec( 396 sqlite3*, /* An open database */ 397 const char *sql, /* SQL to be evaluated */ 398 int (*callback)(void*,int,char**,char**), /* Callback function */ 399 void *, /* 1st argument to callback */ 400 char **errmsg /* Error msg written here */ 401); 402 403/* 404** CAPI3REF: Result Codes 405** KEYWORDS: {result code definitions} 406** 407** Many SQLite functions return an integer result code from the set shown 408** here in order to indicate success or failure. 409** 410** New error codes may be added in future versions of SQLite. 411** 412** See also: [extended result code definitions] 413*/ 414#define SQLITE_OK 0 /* Successful result */ 415/* beginning-of-error-codes */ 416#define SQLITE_ERROR 1 /* SQL error or missing database */ 417#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 418#define SQLITE_PERM 3 /* Access permission denied */ 419#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 420#define SQLITE_BUSY 5 /* The database file is locked */ 421#define SQLITE_LOCKED 6 /* A table in the database is locked */ 422#define SQLITE_NOMEM 7 /* A malloc() failed */ 423#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 424#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 425#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 426#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 427#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 428#define SQLITE_FULL 13 /* Insertion failed because database is full */ 429#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 430#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 431#define SQLITE_EMPTY 16 /* Database is empty */ 432#define SQLITE_SCHEMA 17 /* The database schema changed */ 433#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 434#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 435#define SQLITE_MISMATCH 20 /* Data type mismatch */ 436#define SQLITE_MISUSE 21 /* Library used incorrectly */ 437#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 438#define SQLITE_AUTH 23 /* Authorization denied */ 439#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 440#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 441#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 442#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 443#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 444#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 445#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 446/* end-of-error-codes */ 447 448/* 449** CAPI3REF: Extended Result Codes 450** KEYWORDS: {extended result code definitions} 451** 452** In its default configuration, SQLite API routines return one of 30 integer 453** [result codes]. However, experience has shown that many of 454** these result codes are too coarse-grained. They do not provide as 455** much information about problems as programmers might like. In an effort to 456** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 457** and later) include 458** support for additional result codes that provide more detailed information 459** about errors. These [extended result codes] are enabled or disabled 460** on a per database connection basis using the 461** [sqlite3_extended_result_codes()] API. Or, the extended code for 462** the most recent error can be obtained using 463** [sqlite3_extended_errcode()]. 464*/ 465#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 466#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 467#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 468#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 469#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 470#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 471#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 472#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 473#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 474#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 475#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 476#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 477#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 478#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 479#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 480#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 481#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 482#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 483#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 484#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 485#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 486#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 487#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 488#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 489#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 490#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 491#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 492#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 493#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 494#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 495#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 496#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 497#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 498#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 499#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 500#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 501#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 502#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 503#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 504#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 505#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 506#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 507#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 508#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 509#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 510#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 511#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 512#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 513#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 514#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 515#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 516#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 517#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 518#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 519#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 520#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 521 522/* 523** CAPI3REF: Flags For File Open Operations 524** 525** These bit values are intended for use in the 526** 3rd parameter to the [sqlite3_open_v2()] interface and 527** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 528*/ 529#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 530#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 531#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 532#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 533#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 534#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 535#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 536#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 537#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 538#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 539#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 540#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 541#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 542#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 543#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 544#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 545#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 546#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 547#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 548#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 549 550/* Reserved: 0x00F00000 */ 551 552/* 553** CAPI3REF: Device Characteristics 554** 555** The xDeviceCharacteristics method of the [sqlite3_io_methods] 556** object returns an integer which is a vector of these 557** bit values expressing I/O characteristics of the mass storage 558** device that holds the file that the [sqlite3_io_methods] 559** refers to. 560** 561** The SQLITE_IOCAP_ATOMIC property means that all writes of 562** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 563** mean that writes of blocks that are nnn bytes in size and 564** are aligned to an address which is an integer multiple of 565** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 566** that when data is appended to a file, the data is appended 567** first then the size of the file is extended, never the other 568** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 569** information is written to disk in the same order as calls 570** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 571** after reboot following a crash or power loss, the only bytes in a 572** file that were written at the application level might have changed 573** and that adjacent bytes, even bytes within the same sector are 574** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 575** flag indicate that a file cannot be deleted when open. The 576** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 577** read-only media and cannot be changed even by processes with 578** elevated privileges. 579*/ 580#define SQLITE_IOCAP_ATOMIC 0x00000001 581#define SQLITE_IOCAP_ATOMIC512 0x00000002 582#define SQLITE_IOCAP_ATOMIC1K 0x00000004 583#define SQLITE_IOCAP_ATOMIC2K 0x00000008 584#define SQLITE_IOCAP_ATOMIC4K 0x00000010 585#define SQLITE_IOCAP_ATOMIC8K 0x00000020 586#define SQLITE_IOCAP_ATOMIC16K 0x00000040 587#define SQLITE_IOCAP_ATOMIC32K 0x00000080 588#define SQLITE_IOCAP_ATOMIC64K 0x00000100 589#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 590#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 591#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 592#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 593#define SQLITE_IOCAP_IMMUTABLE 0x00002000 594 595/* 596** CAPI3REF: File Locking Levels 597** 598** SQLite uses one of these integer values as the second 599** argument to calls it makes to the xLock() and xUnlock() methods 600** of an [sqlite3_io_methods] object. 601*/ 602#define SQLITE_LOCK_NONE 0 603#define SQLITE_LOCK_SHARED 1 604#define SQLITE_LOCK_RESERVED 2 605#define SQLITE_LOCK_PENDING 3 606#define SQLITE_LOCK_EXCLUSIVE 4 607 608/* 609** CAPI3REF: Synchronization Type Flags 610** 611** When SQLite invokes the xSync() method of an 612** [sqlite3_io_methods] object it uses a combination of 613** these integer values as the second argument. 614** 615** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 616** sync operation only needs to flush data to mass storage. Inode 617** information need not be flushed. If the lower four bits of the flag 618** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 619** If the lower four bits equal SQLITE_SYNC_FULL, that means 620** to use Mac OS X style fullsync instead of fsync(). 621** 622** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 623** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 624** settings. The [synchronous pragma] determines when calls to the 625** xSync VFS method occur and applies uniformly across all platforms. 626** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 627** energetic or rigorous or forceful the sync operations are and 628** only make a difference on Mac OSX for the default SQLite code. 629** (Third-party VFS implementations might also make the distinction 630** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 631** operating systems natively supported by SQLite, only Mac OSX 632** cares about the difference.) 633*/ 634#define SQLITE_SYNC_NORMAL 0x00002 635#define SQLITE_SYNC_FULL 0x00003 636#define SQLITE_SYNC_DATAONLY 0x00010 637 638/* 639** CAPI3REF: OS Interface Open File Handle 640** 641** An [sqlite3_file] object represents an open file in the 642** [sqlite3_vfs | OS interface layer]. Individual OS interface 643** implementations will 644** want to subclass this object by appending additional fields 645** for their own use. The pMethods entry is a pointer to an 646** [sqlite3_io_methods] object that defines methods for performing 647** I/O operations on the open file. 648*/ 649typedef struct sqlite3_file sqlite3_file; 650struct sqlite3_file { 651 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 652}; 653 654/* 655** CAPI3REF: OS Interface File Virtual Methods Object 656** 657** Every file opened by the [sqlite3_vfs.xOpen] method populates an 658** [sqlite3_file] object (or, more commonly, a subclass of the 659** [sqlite3_file] object) with a pointer to an instance of this object. 660** This object defines the methods used to perform various operations 661** against the open file represented by the [sqlite3_file] object. 662** 663** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 664** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 665** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 666** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 667** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 668** to NULL. 669** 670** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 671** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 672** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 673** flag may be ORed in to indicate that only the data of the file 674** and not its inode needs to be synced. 675** 676** The integer values to xLock() and xUnlock() are one of 677** <ul> 678** <li> [SQLITE_LOCK_NONE], 679** <li> [SQLITE_LOCK_SHARED], 680** <li> [SQLITE_LOCK_RESERVED], 681** <li> [SQLITE_LOCK_PENDING], or 682** <li> [SQLITE_LOCK_EXCLUSIVE]. 683** </ul> 684** xLock() increases the lock. xUnlock() decreases the lock. 685** The xCheckReservedLock() method checks whether any database connection, 686** either in this process or in some other process, is holding a RESERVED, 687** PENDING, or EXCLUSIVE lock on the file. It returns true 688** if such a lock exists and false otherwise. 689** 690** The xFileControl() method is a generic interface that allows custom 691** VFS implementations to directly control an open file using the 692** [sqlite3_file_control()] interface. The second "op" argument is an 693** integer opcode. The third argument is a generic pointer intended to 694** point to a structure that may contain arguments or space in which to 695** write return values. Potential uses for xFileControl() might be 696** functions to enable blocking locks with timeouts, to change the 697** locking strategy (for example to use dot-file locks), to inquire 698** about the status of a lock, or to break stale locks. The SQLite 699** core reserves all opcodes less than 100 for its own use. 700** A [file control opcodes | list of opcodes] less than 100 is available. 701** Applications that define a custom xFileControl method should use opcodes 702** greater than 100 to avoid conflicts. VFS implementations should 703** return [SQLITE_NOTFOUND] for file control opcodes that they do not 704** recognize. 705** 706** The xSectorSize() method returns the sector size of the 707** device that underlies the file. The sector size is the 708** minimum write that can be performed without disturbing 709** other bytes in the file. The xDeviceCharacteristics() 710** method returns a bit vector describing behaviors of the 711** underlying device: 712** 713** <ul> 714** <li> [SQLITE_IOCAP_ATOMIC] 715** <li> [SQLITE_IOCAP_ATOMIC512] 716** <li> [SQLITE_IOCAP_ATOMIC1K] 717** <li> [SQLITE_IOCAP_ATOMIC2K] 718** <li> [SQLITE_IOCAP_ATOMIC4K] 719** <li> [SQLITE_IOCAP_ATOMIC8K] 720** <li> [SQLITE_IOCAP_ATOMIC16K] 721** <li> [SQLITE_IOCAP_ATOMIC32K] 722** <li> [SQLITE_IOCAP_ATOMIC64K] 723** <li> [SQLITE_IOCAP_SAFE_APPEND] 724** <li> [SQLITE_IOCAP_SEQUENTIAL] 725** </ul> 726** 727** The SQLITE_IOCAP_ATOMIC property means that all writes of 728** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 729** mean that writes of blocks that are nnn bytes in size and 730** are aligned to an address which is an integer multiple of 731** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 732** that when data is appended to a file, the data is appended 733** first then the size of the file is extended, never the other 734** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 735** information is written to disk in the same order as calls 736** to xWrite(). 737** 738** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 739** in the unread portions of the buffer with zeros. A VFS that 740** fails to zero-fill short reads might seem to work. However, 741** failure to zero-fill short reads will eventually lead to 742** database corruption. 743*/ 744typedef struct sqlite3_io_methods sqlite3_io_methods; 745struct sqlite3_io_methods { 746 int iVersion; 747 int (*xClose)(sqlite3_file*); 748 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 749 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 750 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 751 int (*xSync)(sqlite3_file*, int flags); 752 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 753 int (*xLock)(sqlite3_file*, int); 754 int (*xUnlock)(sqlite3_file*, int); 755 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 756 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 757 int (*xSectorSize)(sqlite3_file*); 758 int (*xDeviceCharacteristics)(sqlite3_file*); 759 /* Methods above are valid for version 1 */ 760 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 761 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 762 void (*xShmBarrier)(sqlite3_file*); 763 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 764 /* Methods above are valid for version 2 */ 765 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 766 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 767 /* Methods above are valid for version 3 */ 768 /* Additional methods may be added in future releases */ 769}; 770 771/* 772** CAPI3REF: Standard File Control Opcodes 773** KEYWORDS: {file control opcodes} {file control opcode} 774** 775** These integer constants are opcodes for the xFileControl method 776** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 777** interface. 778** 779** <ul> 780** <li>[[SQLITE_FCNTL_LOCKSTATE]] 781** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 782** opcode causes the xFileControl method to write the current state of 783** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 784** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 785** into an integer that the pArg argument points to. This capability 786** is used during testing and is only available when the SQLITE_TEST 787** compile-time option is used. 788** 789** <li>[[SQLITE_FCNTL_SIZE_HINT]] 790** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 791** layer a hint of how large the database file will grow to be during the 792** current transaction. This hint is not guaranteed to be accurate but it 793** is often close. The underlying VFS might choose to preallocate database 794** file space based on this hint in order to help writes to the database 795** file run faster. 796** 797** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 798** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 799** extends and truncates the database file in chunks of a size specified 800** by the user. The fourth argument to [sqlite3_file_control()] should 801** point to an integer (type int) containing the new chunk-size to use 802** for the nominated database. Allocating database file space in large 803** chunks (say 1MB at a time), may reduce file-system fragmentation and 804** improve performance on some systems. 805** 806** <li>[[SQLITE_FCNTL_FILE_POINTER]] 807** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 808** to the [sqlite3_file] object associated with a particular database 809** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 810** 811** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 812** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 813** to the [sqlite3_file] object associated with the journal file (either 814** the [rollback journal] or the [write-ahead log]) for a particular database 815** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 816** 817** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 818** No longer in use. 819** 820** <li>[[SQLITE_FCNTL_SYNC]] 821** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 822** sent to the VFS immediately before the xSync method is invoked on a 823** database file descriptor. Or, if the xSync method is not invoked 824** because the user has configured SQLite with 825** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 826** of the xSync method. In most cases, the pointer argument passed with 827** this file-control is NULL. However, if the database file is being synced 828** as part of a multi-database commit, the argument points to a nul-terminated 829** string containing the transactions master-journal file name. VFSes that 830** do not need this signal should silently ignore this opcode. Applications 831** should not call [sqlite3_file_control()] with this opcode as doing so may 832** disrupt the operation of the specialized VFSes that do require it. 833** 834** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 835** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 836** and sent to the VFS after a transaction has been committed immediately 837** but before the database is unlocked. VFSes that do not need this signal 838** should silently ignore this opcode. Applications should not call 839** [sqlite3_file_control()] with this opcode as doing so may disrupt the 840** operation of the specialized VFSes that do require it. 841** 842** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 843** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 844** retry counts and intervals for certain disk I/O operations for the 845** windows [VFS] in order to provide robustness in the presence of 846** anti-virus programs. By default, the windows VFS will retry file read, 847** file write, and file delete operations up to 10 times, with a delay 848** of 25 milliseconds before the first retry and with the delay increasing 849** by an additional 25 milliseconds with each subsequent retry. This 850** opcode allows these two values (10 retries and 25 milliseconds of delay) 851** to be adjusted. The values are changed for all database connections 852** within the same process. The argument is a pointer to an array of two 853** integers where the first integer i the new retry count and the second 854** integer is the delay. If either integer is negative, then the setting 855** is not changed but instead the prior value of that setting is written 856** into the array entry, allowing the current retry settings to be 857** interrogated. The zDbName parameter is ignored. 858** 859** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 860** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 861** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 862** write ahead log and shared memory files used for transaction control 863** are automatically deleted when the latest connection to the database 864** closes. Setting persistent WAL mode causes those files to persist after 865** close. Persisting the files is useful when other processes that do not 866** have write permission on the directory containing the database file want 867** to read the database file, as the WAL and shared memory files must exist 868** in order for the database to be readable. The fourth parameter to 869** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 870** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 871** WAL mode. If the integer is -1, then it is overwritten with the current 872** WAL persistence setting. 873** 874** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 875** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 876** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 877** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 878** xDeviceCharacteristics methods. The fourth parameter to 879** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 880** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 881** mode. If the integer is -1, then it is overwritten with the current 882** zero-damage mode setting. 883** 884** <li>[[SQLITE_FCNTL_OVERWRITE]] 885** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 886** a write transaction to indicate that, unless it is rolled back for some 887** reason, the entire database file will be overwritten by the current 888** transaction. This is used by VACUUM operations. 889** 890** <li>[[SQLITE_FCNTL_VFSNAME]] 891** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 892** all [VFSes] in the VFS stack. The names are of all VFS shims and the 893** final bottom-level VFS are written into memory obtained from 894** [sqlite3_malloc()] and the result is stored in the char* variable 895** that the fourth parameter of [sqlite3_file_control()] points to. 896** The caller is responsible for freeing the memory when done. As with 897** all file-control actions, there is no guarantee that this will actually 898** do anything. Callers should initialize the char* variable to a NULL 899** pointer in case this file-control is not implemented. This file-control 900** is intended for diagnostic use only. 901** 902** <li>[[SQLITE_FCNTL_VFS_POINTER]] 903** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 904** [VFSes] currently in use. ^(The argument X in 905** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 906** of type "[sqlite3_vfs] **". This opcodes will set *X 907** to a pointer to the top-level VFS.)^ 908** ^When there are multiple VFS shims in the stack, this opcode finds the 909** upper-most shim only. 910** 911** <li>[[SQLITE_FCNTL_PRAGMA]] 912** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 913** file control is sent to the open [sqlite3_file] object corresponding 914** to the database file to which the pragma statement refers. ^The argument 915** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 916** pointers to strings (char**) in which the second element of the array 917** is the name of the pragma and the third element is the argument to the 918** pragma or NULL if the pragma has no argument. ^The handler for an 919** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 920** of the char** argument point to a string obtained from [sqlite3_mprintf()] 921** or the equivalent and that string will become the result of the pragma or 922** the error message if the pragma fails. ^If the 923** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 924** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 925** file control returns [SQLITE_OK], then the parser assumes that the 926** VFS has handled the PRAGMA itself and the parser generates a no-op 927** prepared statement if result string is NULL, or that returns a copy 928** of the result string if the string is non-NULL. 929** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 930** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 931** that the VFS encountered an error while handling the [PRAGMA] and the 932** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 933** file control occurs at the beginning of pragma statement analysis and so 934** it is able to override built-in [PRAGMA] statements. 935** 936** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 937** ^The [SQLITE_FCNTL_BUSYHANDLER] 938** file-control may be invoked by SQLite on the database file handle 939** shortly after it is opened in order to provide a custom VFS with access 940** to the connections busy-handler callback. The argument is of type (void **) 941** - an array of two (void *) values. The first (void *) actually points 942** to a function of type (int (*)(void *)). In order to invoke the connections 943** busy-handler, this function should be invoked with the second (void *) in 944** the array as the only argument. If it returns non-zero, then the operation 945** should be retried. If it returns zero, the custom VFS should abandon the 946** current operation. 947** 948** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 949** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 950** to have SQLite generate a 951** temporary filename using the same algorithm that is followed to generate 952** temporary filenames for TEMP tables and other internal uses. The 953** argument should be a char** which will be filled with the filename 954** written into memory obtained from [sqlite3_malloc()]. The caller should 955** invoke [sqlite3_free()] on the result to avoid a memory leak. 956** 957** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 958** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 959** maximum number of bytes that will be used for memory-mapped I/O. 960** The argument is a pointer to a value of type sqlite3_int64 that 961** is an advisory maximum number of bytes in the file to memory map. The 962** pointer is overwritten with the old value. The limit is not changed if 963** the value originally pointed to is negative, and so the current limit 964** can be queried by passing in a pointer to a negative number. This 965** file-control is used internally to implement [PRAGMA mmap_size]. 966** 967** <li>[[SQLITE_FCNTL_TRACE]] 968** The [SQLITE_FCNTL_TRACE] file control provides advisory information 969** to the VFS about what the higher layers of the SQLite stack are doing. 970** This file control is used by some VFS activity tracing [shims]. 971** The argument is a zero-terminated string. Higher layers in the 972** SQLite stack may generate instances of this file control if 973** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 974** 975** <li>[[SQLITE_FCNTL_HAS_MOVED]] 976** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 977** pointer to an integer and it writes a boolean into that integer depending 978** on whether or not the file has been renamed, moved, or deleted since it 979** was first opened. 980** 981** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 982** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 983** underlying native file handle associated with a file handle. This file 984** control interprets its argument as a pointer to a native file handle and 985** writes the resulting value there. 986** 987** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 988** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 989** opcode causes the xFileControl method to swap the file handle with the one 990** pointed to by the pArg argument. This capability is used during testing 991** and only needs to be supported when SQLITE_TEST is defined. 992** 993** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 994** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 995** be advantageous to block on the next WAL lock if the lock is not immediately 996** available. The WAL subsystem issues this signal during rare 997** circumstances in order to fix a problem with priority inversion. 998** Applications should <em>not</em> use this file-control. 999** 1000** <li>[[SQLITE_FCNTL_ZIPVFS]] 1001** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1002** VFS should return SQLITE_NOTFOUND for this opcode. 1003** 1004** <li>[[SQLITE_FCNTL_RBU]] 1005** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1006** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1007** this opcode. 1008** </ul> 1009*/ 1010#define SQLITE_FCNTL_LOCKSTATE 1 1011#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1012#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1013#define SQLITE_FCNTL_LAST_ERRNO 4 1014#define SQLITE_FCNTL_SIZE_HINT 5 1015#define SQLITE_FCNTL_CHUNK_SIZE 6 1016#define SQLITE_FCNTL_FILE_POINTER 7 1017#define SQLITE_FCNTL_SYNC_OMITTED 8 1018#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1019#define SQLITE_FCNTL_PERSIST_WAL 10 1020#define SQLITE_FCNTL_OVERWRITE 11 1021#define SQLITE_FCNTL_VFSNAME 12 1022#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1023#define SQLITE_FCNTL_PRAGMA 14 1024#define SQLITE_FCNTL_BUSYHANDLER 15 1025#define SQLITE_FCNTL_TEMPFILENAME 16 1026#define SQLITE_FCNTL_MMAP_SIZE 18 1027#define SQLITE_FCNTL_TRACE 19 1028#define SQLITE_FCNTL_HAS_MOVED 20 1029#define SQLITE_FCNTL_SYNC 21 1030#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1031#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1032#define SQLITE_FCNTL_WAL_BLOCK 24 1033#define SQLITE_FCNTL_ZIPVFS 25 1034#define SQLITE_FCNTL_RBU 26 1035#define SQLITE_FCNTL_VFS_POINTER 27 1036#define SQLITE_FCNTL_JOURNAL_POINTER 28 1037#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1038#define SQLITE_FCNTL_PDB 30 1039 1040/* deprecated names */ 1041#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1042#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1043#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1044 1045 1046/* 1047** CAPI3REF: Mutex Handle 1048** 1049** The mutex module within SQLite defines [sqlite3_mutex] to be an 1050** abstract type for a mutex object. The SQLite core never looks 1051** at the internal representation of an [sqlite3_mutex]. It only 1052** deals with pointers to the [sqlite3_mutex] object. 1053** 1054** Mutexes are created using [sqlite3_mutex_alloc()]. 1055*/ 1056typedef struct sqlite3_mutex sqlite3_mutex; 1057 1058/* 1059** CAPI3REF: Loadable Extension Thunk 1060** 1061** A pointer to the opaque sqlite3_api_routines structure is passed as 1062** the third parameter to entry points of [loadable extensions]. This 1063** structure must be typedefed in order to work around compiler warnings 1064** on some platforms. 1065*/ 1066typedef struct sqlite3_api_routines sqlite3_api_routines; 1067 1068/* 1069** CAPI3REF: OS Interface Object 1070** 1071** An instance of the sqlite3_vfs object defines the interface between 1072** the SQLite core and the underlying operating system. The "vfs" 1073** in the name of the object stands for "virtual file system". See 1074** the [VFS | VFS documentation] for further information. 1075** 1076** The value of the iVersion field is initially 1 but may be larger in 1077** future versions of SQLite. Additional fields may be appended to this 1078** object when the iVersion value is increased. Note that the structure 1079** of the sqlite3_vfs object changes in the transaction between 1080** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 1081** modified. 1082** 1083** The szOsFile field is the size of the subclassed [sqlite3_file] 1084** structure used by this VFS. mxPathname is the maximum length of 1085** a pathname in this VFS. 1086** 1087** Registered sqlite3_vfs objects are kept on a linked list formed by 1088** the pNext pointer. The [sqlite3_vfs_register()] 1089** and [sqlite3_vfs_unregister()] interfaces manage this list 1090** in a thread-safe way. The [sqlite3_vfs_find()] interface 1091** searches the list. Neither the application code nor the VFS 1092** implementation should use the pNext pointer. 1093** 1094** The pNext field is the only field in the sqlite3_vfs 1095** structure that SQLite will ever modify. SQLite will only access 1096** or modify this field while holding a particular static mutex. 1097** The application should never modify anything within the sqlite3_vfs 1098** object once the object has been registered. 1099** 1100** The zName field holds the name of the VFS module. The name must 1101** be unique across all VFS modules. 1102** 1103** [[sqlite3_vfs.xOpen]] 1104** ^SQLite guarantees that the zFilename parameter to xOpen 1105** is either a NULL pointer or string obtained 1106** from xFullPathname() with an optional suffix added. 1107** ^If a suffix is added to the zFilename parameter, it will 1108** consist of a single "-" character followed by no more than 1109** 11 alphanumeric and/or "-" characters. 1110** ^SQLite further guarantees that 1111** the string will be valid and unchanged until xClose() is 1112** called. Because of the previous sentence, 1113** the [sqlite3_file] can safely store a pointer to the 1114** filename if it needs to remember the filename for some reason. 1115** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1116** must invent its own temporary name for the file. ^Whenever the 1117** xFilename parameter is NULL it will also be the case that the 1118** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1119** 1120** The flags argument to xOpen() includes all bits set in 1121** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1122** or [sqlite3_open16()] is used, then flags includes at least 1123** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1124** If xOpen() opens a file read-only then it sets *pOutFlags to 1125** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1126** 1127** ^(SQLite will also add one of the following flags to the xOpen() 1128** call, depending on the object being opened: 1129** 1130** <ul> 1131** <li> [SQLITE_OPEN_MAIN_DB] 1132** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1133** <li> [SQLITE_OPEN_TEMP_DB] 1134** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1135** <li> [SQLITE_OPEN_TRANSIENT_DB] 1136** <li> [SQLITE_OPEN_SUBJOURNAL] 1137** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1138** <li> [SQLITE_OPEN_WAL] 1139** </ul>)^ 1140** 1141** The file I/O implementation can use the object type flags to 1142** change the way it deals with files. For example, an application 1143** that does not care about crash recovery or rollback might make 1144** the open of a journal file a no-op. Writes to this journal would 1145** also be no-ops, and any attempt to read the journal would return 1146** SQLITE_IOERR. Or the implementation might recognize that a database 1147** file will be doing page-aligned sector reads and writes in a random 1148** order and set up its I/O subsystem accordingly. 1149** 1150** SQLite might also add one of the following flags to the xOpen method: 1151** 1152** <ul> 1153** <li> [SQLITE_OPEN_DELETEONCLOSE] 1154** <li> [SQLITE_OPEN_EXCLUSIVE] 1155** </ul> 1156** 1157** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1158** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1159** will be set for TEMP databases and their journals, transient 1160** databases, and subjournals. 1161** 1162** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1163** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1164** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1165** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1166** SQLITE_OPEN_CREATE, is used to indicate that file should always 1167** be created, and that it is an error if it already exists. 1168** It is <i>not</i> used to indicate the file should be opened 1169** for exclusive access. 1170** 1171** ^At least szOsFile bytes of memory are allocated by SQLite 1172** to hold the [sqlite3_file] structure passed as the third 1173** argument to xOpen. The xOpen method does not have to 1174** allocate the structure; it should just fill it in. Note that 1175** the xOpen method must set the sqlite3_file.pMethods to either 1176** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1177** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1178** element will be valid after xOpen returns regardless of the success 1179** or failure of the xOpen call. 1180** 1181** [[sqlite3_vfs.xAccess]] 1182** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1183** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1184** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1185** to test whether a file is at least readable. The file can be a 1186** directory. 1187** 1188** ^SQLite will always allocate at least mxPathname+1 bytes for the 1189** output buffer xFullPathname. The exact size of the output buffer 1190** is also passed as a parameter to both methods. If the output buffer 1191** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1192** handled as a fatal error by SQLite, vfs implementations should endeavor 1193** to prevent this by setting mxPathname to a sufficiently large value. 1194** 1195** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1196** interfaces are not strictly a part of the filesystem, but they are 1197** included in the VFS structure for completeness. 1198** The xRandomness() function attempts to return nBytes bytes 1199** of good-quality randomness into zOut. The return value is 1200** the actual number of bytes of randomness obtained. 1201** The xSleep() method causes the calling thread to sleep for at 1202** least the number of microseconds given. ^The xCurrentTime() 1203** method returns a Julian Day Number for the current date and time as 1204** a floating point value. 1205** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1206** Day Number multiplied by 86400000 (the number of milliseconds in 1207** a 24-hour day). 1208** ^SQLite will use the xCurrentTimeInt64() method to get the current 1209** date and time if that method is available (if iVersion is 2 or 1210** greater and the function pointer is not NULL) and will fall back 1211** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1212** 1213** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1214** are not used by the SQLite core. These optional interfaces are provided 1215** by some VFSes to facilitate testing of the VFS code. By overriding 1216** system calls with functions under its control, a test program can 1217** simulate faults and error conditions that would otherwise be difficult 1218** or impossible to induce. The set of system calls that can be overridden 1219** varies from one VFS to another, and from one version of the same VFS to the 1220** next. Applications that use these interfaces must be prepared for any 1221** or all of these interfaces to be NULL or for their behavior to change 1222** from one release to the next. Applications must not attempt to access 1223** any of these methods if the iVersion of the VFS is less than 3. 1224*/ 1225typedef struct sqlite3_vfs sqlite3_vfs; 1226typedef void (*sqlite3_syscall_ptr)(void); 1227struct sqlite3_vfs { 1228 int iVersion; /* Structure version number (currently 3) */ 1229 int szOsFile; /* Size of subclassed sqlite3_file */ 1230 int mxPathname; /* Maximum file pathname length */ 1231 sqlite3_vfs *pNext; /* Next registered VFS */ 1232 const char *zName; /* Name of this virtual file system */ 1233 void *pAppData; /* Pointer to application-specific data */ 1234 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1235 int flags, int *pOutFlags); 1236 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1237 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1238 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1239 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1240 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1241 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1242 void (*xDlClose)(sqlite3_vfs*, void*); 1243 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1244 int (*xSleep)(sqlite3_vfs*, int microseconds); 1245 int (*xCurrentTime)(sqlite3_vfs*, double*); 1246 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1247 /* 1248 ** The methods above are in version 1 of the sqlite_vfs object 1249 ** definition. Those that follow are added in version 2 or later 1250 */ 1251 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1252 /* 1253 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1254 ** Those below are for version 3 and greater. 1255 */ 1256 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1257 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1258 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1259 /* 1260 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1261 ** New fields may be appended in future versions. The iVersion 1262 ** value will increment whenever this happens. 1263 */ 1264}; 1265 1266/* 1267** CAPI3REF: Flags for the xAccess VFS method 1268** 1269** These integer constants can be used as the third parameter to 1270** the xAccess method of an [sqlite3_vfs] object. They determine 1271** what kind of permissions the xAccess method is looking for. 1272** With SQLITE_ACCESS_EXISTS, the xAccess method 1273** simply checks whether the file exists. 1274** With SQLITE_ACCESS_READWRITE, the xAccess method 1275** checks whether the named directory is both readable and writable 1276** (in other words, if files can be added, removed, and renamed within 1277** the directory). 1278** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1279** [temp_store_directory pragma], though this could change in a future 1280** release of SQLite. 1281** With SQLITE_ACCESS_READ, the xAccess method 1282** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1283** currently unused, though it might be used in a future release of 1284** SQLite. 1285*/ 1286#define SQLITE_ACCESS_EXISTS 0 1287#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1288#define SQLITE_ACCESS_READ 2 /* Unused */ 1289 1290/* 1291** CAPI3REF: Flags for the xShmLock VFS method 1292** 1293** These integer constants define the various locking operations 1294** allowed by the xShmLock method of [sqlite3_io_methods]. The 1295** following are the only legal combinations of flags to the 1296** xShmLock method: 1297** 1298** <ul> 1299** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1300** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1301** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1302** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1303** </ul> 1304** 1305** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1306** was given on the corresponding lock. 1307** 1308** The xShmLock method can transition between unlocked and SHARED or 1309** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1310** and EXCLUSIVE. 1311*/ 1312#define SQLITE_SHM_UNLOCK 1 1313#define SQLITE_SHM_LOCK 2 1314#define SQLITE_SHM_SHARED 4 1315#define SQLITE_SHM_EXCLUSIVE 8 1316 1317/* 1318** CAPI3REF: Maximum xShmLock index 1319** 1320** The xShmLock method on [sqlite3_io_methods] may use values 1321** between 0 and this upper bound as its "offset" argument. 1322** The SQLite core will never attempt to acquire or release a 1323** lock outside of this range 1324*/ 1325#define SQLITE_SHM_NLOCK 8 1326 1327 1328/* 1329** CAPI3REF: Initialize The SQLite Library 1330** 1331** ^The sqlite3_initialize() routine initializes the 1332** SQLite library. ^The sqlite3_shutdown() routine 1333** deallocates any resources that were allocated by sqlite3_initialize(). 1334** These routines are designed to aid in process initialization and 1335** shutdown on embedded systems. Workstation applications using 1336** SQLite normally do not need to invoke either of these routines. 1337** 1338** A call to sqlite3_initialize() is an "effective" call if it is 1339** the first time sqlite3_initialize() is invoked during the lifetime of 1340** the process, or if it is the first time sqlite3_initialize() is invoked 1341** following a call to sqlite3_shutdown(). ^(Only an effective call 1342** of sqlite3_initialize() does any initialization. All other calls 1343** are harmless no-ops.)^ 1344** 1345** A call to sqlite3_shutdown() is an "effective" call if it is the first 1346** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1347** an effective call to sqlite3_shutdown() does any deinitialization. 1348** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1349** 1350** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1351** is not. The sqlite3_shutdown() interface must only be called from a 1352** single thread. All open [database connections] must be closed and all 1353** other SQLite resources must be deallocated prior to invoking 1354** sqlite3_shutdown(). 1355** 1356** Among other things, ^sqlite3_initialize() will invoke 1357** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1358** will invoke sqlite3_os_end(). 1359** 1360** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1361** ^If for some reason, sqlite3_initialize() is unable to initialize 1362** the library (perhaps it is unable to allocate a needed resource such 1363** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1364** 1365** ^The sqlite3_initialize() routine is called internally by many other 1366** SQLite interfaces so that an application usually does not need to 1367** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1368** calls sqlite3_initialize() so the SQLite library will be automatically 1369** initialized when [sqlite3_open()] is called if it has not be initialized 1370** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1371** compile-time option, then the automatic calls to sqlite3_initialize() 1372** are omitted and the application must call sqlite3_initialize() directly 1373** prior to using any other SQLite interface. For maximum portability, 1374** it is recommended that applications always invoke sqlite3_initialize() 1375** directly prior to using any other SQLite interface. Future releases 1376** of SQLite may require this. In other words, the behavior exhibited 1377** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1378** default behavior in some future release of SQLite. 1379** 1380** The sqlite3_os_init() routine does operating-system specific 1381** initialization of the SQLite library. The sqlite3_os_end() 1382** routine undoes the effect of sqlite3_os_init(). Typical tasks 1383** performed by these routines include allocation or deallocation 1384** of static resources, initialization of global variables, 1385** setting up a default [sqlite3_vfs] module, or setting up 1386** a default configuration using [sqlite3_config()]. 1387** 1388** The application should never invoke either sqlite3_os_init() 1389** or sqlite3_os_end() directly. The application should only invoke 1390** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1391** interface is called automatically by sqlite3_initialize() and 1392** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1393** implementations for sqlite3_os_init() and sqlite3_os_end() 1394** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1395** When [custom builds | built for other platforms] 1396** (using the [SQLITE_OS_OTHER=1] compile-time 1397** option) the application must supply a suitable implementation for 1398** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1399** implementation of sqlite3_os_init() or sqlite3_os_end() 1400** must return [SQLITE_OK] on success and some other [error code] upon 1401** failure. 1402*/ 1403int sqlite3_initialize(void); 1404int sqlite3_shutdown(void); 1405int sqlite3_os_init(void); 1406int sqlite3_os_end(void); 1407 1408/* 1409** CAPI3REF: Configuring The SQLite Library 1410** 1411** The sqlite3_config() interface is used to make global configuration 1412** changes to SQLite in order to tune SQLite to the specific needs of 1413** the application. The default configuration is recommended for most 1414** applications and so this routine is usually not necessary. It is 1415** provided to support rare applications with unusual needs. 1416** 1417** <b>The sqlite3_config() interface is not threadsafe. The application 1418** must ensure that no other SQLite interfaces are invoked by other 1419** threads while sqlite3_config() is running.</b> 1420** 1421** The sqlite3_config() interface 1422** may only be invoked prior to library initialization using 1423** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1424** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1425** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1426** Note, however, that ^sqlite3_config() can be called as part of the 1427** implementation of an application-defined [sqlite3_os_init()]. 1428** 1429** The first argument to sqlite3_config() is an integer 1430** [configuration option] that determines 1431** what property of SQLite is to be configured. Subsequent arguments 1432** vary depending on the [configuration option] 1433** in the first argument. 1434** 1435** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1436** ^If the option is unknown or SQLite is unable to set the option 1437** then this routine returns a non-zero [error code]. 1438*/ 1439int sqlite3_config(int, ...); 1440 1441/* 1442** CAPI3REF: Configure database connections 1443** METHOD: sqlite3 1444** 1445** The sqlite3_db_config() interface is used to make configuration 1446** changes to a [database connection]. The interface is similar to 1447** [sqlite3_config()] except that the changes apply to a single 1448** [database connection] (specified in the first argument). 1449** 1450** The second argument to sqlite3_db_config(D,V,...) is the 1451** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1452** that indicates what aspect of the [database connection] is being configured. 1453** Subsequent arguments vary depending on the configuration verb. 1454** 1455** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1456** the call is considered successful. 1457*/ 1458int sqlite3_db_config(sqlite3*, int op, ...); 1459 1460/* 1461** CAPI3REF: Memory Allocation Routines 1462** 1463** An instance of this object defines the interface between SQLite 1464** and low-level memory allocation routines. 1465** 1466** This object is used in only one place in the SQLite interface. 1467** A pointer to an instance of this object is the argument to 1468** [sqlite3_config()] when the configuration option is 1469** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1470** By creating an instance of this object 1471** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1472** during configuration, an application can specify an alternative 1473** memory allocation subsystem for SQLite to use for all of its 1474** dynamic memory needs. 1475** 1476** Note that SQLite comes with several [built-in memory allocators] 1477** that are perfectly adequate for the overwhelming majority of applications 1478** and that this object is only useful to a tiny minority of applications 1479** with specialized memory allocation requirements. This object is 1480** also used during testing of SQLite in order to specify an alternative 1481** memory allocator that simulates memory out-of-memory conditions in 1482** order to verify that SQLite recovers gracefully from such 1483** conditions. 1484** 1485** The xMalloc, xRealloc, and xFree methods must work like the 1486** malloc(), realloc() and free() functions from the standard C library. 1487** ^SQLite guarantees that the second argument to 1488** xRealloc is always a value returned by a prior call to xRoundup. 1489** 1490** xSize should return the allocated size of a memory allocation 1491** previously obtained from xMalloc or xRealloc. The allocated size 1492** is always at least as big as the requested size but may be larger. 1493** 1494** The xRoundup method returns what would be the allocated size of 1495** a memory allocation given a particular requested size. Most memory 1496** allocators round up memory allocations at least to the next multiple 1497** of 8. Some allocators round up to a larger multiple or to a power of 2. 1498** Every memory allocation request coming in through [sqlite3_malloc()] 1499** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1500** that causes the corresponding memory allocation to fail. 1501** 1502** The xInit method initializes the memory allocator. For example, 1503** it might allocate any require mutexes or initialize internal data 1504** structures. The xShutdown method is invoked (indirectly) by 1505** [sqlite3_shutdown()] and should deallocate any resources acquired 1506** by xInit. The pAppData pointer is used as the only parameter to 1507** xInit and xShutdown. 1508** 1509** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1510** the xInit method, so the xInit method need not be threadsafe. The 1511** xShutdown method is only called from [sqlite3_shutdown()] so it does 1512** not need to be threadsafe either. For all other methods, SQLite 1513** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1514** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1515** it is by default) and so the methods are automatically serialized. 1516** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1517** methods must be threadsafe or else make their own arrangements for 1518** serialization. 1519** 1520** SQLite will never invoke xInit() more than once without an intervening 1521** call to xShutdown(). 1522*/ 1523typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1524struct sqlite3_mem_methods { 1525 void *(*xMalloc)(int); /* Memory allocation function */ 1526 void (*xFree)(void*); /* Free a prior allocation */ 1527 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1528 int (*xSize)(void*); /* Return the size of an allocation */ 1529 int (*xRoundup)(int); /* Round up request size to allocation size */ 1530 int (*xInit)(void*); /* Initialize the memory allocator */ 1531 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1532 void *pAppData; /* Argument to xInit() and xShutdown() */ 1533}; 1534 1535/* 1536** CAPI3REF: Configuration Options 1537** KEYWORDS: {configuration option} 1538** 1539** These constants are the available integer configuration options that 1540** can be passed as the first argument to the [sqlite3_config()] interface. 1541** 1542** New configuration options may be added in future releases of SQLite. 1543** Existing configuration options might be discontinued. Applications 1544** should check the return code from [sqlite3_config()] to make sure that 1545** the call worked. The [sqlite3_config()] interface will return a 1546** non-zero [error code] if a discontinued or unsupported configuration option 1547** is invoked. 1548** 1549** <dl> 1550** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1551** <dd>There are no arguments to this option. ^This option sets the 1552** [threading mode] to Single-thread. In other words, it disables 1553** all mutexing and puts SQLite into a mode where it can only be used 1554** by a single thread. ^If SQLite is compiled with 1555** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1556** it is not possible to change the [threading mode] from its default 1557** value of Single-thread and so [sqlite3_config()] will return 1558** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1559** configuration option.</dd> 1560** 1561** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1562** <dd>There are no arguments to this option. ^This option sets the 1563** [threading mode] to Multi-thread. In other words, it disables 1564** mutexing on [database connection] and [prepared statement] objects. 1565** The application is responsible for serializing access to 1566** [database connections] and [prepared statements]. But other mutexes 1567** are enabled so that SQLite will be safe to use in a multi-threaded 1568** environment as long as no two threads attempt to use the same 1569** [database connection] at the same time. ^If SQLite is compiled with 1570** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1571** it is not possible to set the Multi-thread [threading mode] and 1572** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1573** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1574** 1575** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1576** <dd>There are no arguments to this option. ^This option sets the 1577** [threading mode] to Serialized. In other words, this option enables 1578** all mutexes including the recursive 1579** mutexes on [database connection] and [prepared statement] objects. 1580** In this mode (which is the default when SQLite is compiled with 1581** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1582** to [database connections] and [prepared statements] so that the 1583** application is free to use the same [database connection] or the 1584** same [prepared statement] in different threads at the same time. 1585** ^If SQLite is compiled with 1586** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1587** it is not possible to set the Serialized [threading mode] and 1588** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1589** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1590** 1591** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1592** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1593** a pointer to an instance of the [sqlite3_mem_methods] structure. 1594** The argument specifies 1595** alternative low-level memory allocation routines to be used in place of 1596** the memory allocation routines built into SQLite.)^ ^SQLite makes 1597** its own private copy of the content of the [sqlite3_mem_methods] structure 1598** before the [sqlite3_config()] call returns.</dd> 1599** 1600** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1601** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1602** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1603** The [sqlite3_mem_methods] 1604** structure is filled with the currently defined memory allocation routines.)^ 1605** This option can be used to overload the default memory allocation 1606** routines with a wrapper that simulations memory allocation failure or 1607** tracks memory usage, for example. </dd> 1608** 1609** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1610** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1611** interpreted as a boolean, which enables or disables the collection of 1612** memory allocation statistics. ^(When memory allocation statistics are 1613** disabled, the following SQLite interfaces become non-operational: 1614** <ul> 1615** <li> [sqlite3_memory_used()] 1616** <li> [sqlite3_memory_highwater()] 1617** <li> [sqlite3_soft_heap_limit64()] 1618** <li> [sqlite3_status64()] 1619** </ul>)^ 1620** ^Memory allocation statistics are enabled by default unless SQLite is 1621** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1622** allocation statistics are disabled by default. 1623** </dd> 1624** 1625** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1626** <dd> ^The SQLITE_CONFIG_SCRATCH option specifies a static memory buffer 1627** that SQLite can use for scratch memory. ^(There are three arguments 1628** to SQLITE_CONFIG_SCRATCH: A pointer an 8-byte 1629** aligned memory buffer from which the scratch allocations will be 1630** drawn, the size of each scratch allocation (sz), 1631** and the maximum number of scratch allocations (N).)^ 1632** The first argument must be a pointer to an 8-byte aligned buffer 1633** of at least sz*N bytes of memory. 1634** ^SQLite will not use more than one scratch buffers per thread. 1635** ^SQLite will never request a scratch buffer that is more than 6 1636** times the database page size. 1637** ^If SQLite needs needs additional 1638** scratch memory beyond what is provided by this configuration option, then 1639** [sqlite3_malloc()] will be used to obtain the memory needed.<p> 1640** ^When the application provides any amount of scratch memory using 1641** SQLITE_CONFIG_SCRATCH, SQLite avoids unnecessary large 1642** [sqlite3_malloc|heap allocations]. 1643** This can help [Robson proof|prevent memory allocation failures] due to heap 1644** fragmentation in low-memory embedded systems. 1645** </dd> 1646** 1647** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1648** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1649** that SQLite can use for the database page cache with the default page 1650** cache implementation. 1651** This configuration option is a no-op if an application-define page 1652** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1653** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1654** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1655** and the number of cache lines (N). 1656** The sz argument should be the size of the largest database page 1657** (a power of two between 512 and 65536) plus some extra bytes for each 1658** page header. ^The number of extra bytes needed by the page header 1659** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1660** ^It is harmless, apart from the wasted memory, 1661** for the sz parameter to be larger than necessary. The pMem 1662** argument must be either a NULL pointer or a pointer to an 8-byte 1663** aligned block of memory of at least sz*N bytes, otherwise 1664** subsequent behavior is undefined. 1665** ^When pMem is not NULL, SQLite will strive to use the memory provided 1666** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1667** a page cache line is larger than sz bytes or if all of the pMem buffer 1668** is exhausted. 1669** ^If pMem is NULL and N is non-zero, then each database connection 1670** does an initial bulk allocation for page cache memory 1671** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1672** of -1024*N bytes if N is negative, . ^If additional 1673** page cache memory is needed beyond what is provided by the initial 1674** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1675** additional cache line. </dd> 1676** 1677** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1678** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1679** that SQLite will use for all of its dynamic memory allocation needs 1680** beyond those provided for by [SQLITE_CONFIG_SCRATCH] and 1681** [SQLITE_CONFIG_PAGECACHE]. 1682** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1683** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1684** [SQLITE_ERROR] if invoked otherwise. 1685** ^There are three arguments to SQLITE_CONFIG_HEAP: 1686** An 8-byte aligned pointer to the memory, 1687** the number of bytes in the memory buffer, and the minimum allocation size. 1688** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1689** to using its default memory allocator (the system malloc() implementation), 1690** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1691** memory pointer is not NULL then the alternative memory 1692** allocator is engaged to handle all of SQLites memory allocation needs. 1693** The first pointer (the memory pointer) must be aligned to an 8-byte 1694** boundary or subsequent behavior of SQLite will be undefined. 1695** The minimum allocation size is capped at 2**12. Reasonable values 1696** for the minimum allocation size are 2**5 through 2**8.</dd> 1697** 1698** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1699** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1700** pointer to an instance of the [sqlite3_mutex_methods] structure. 1701** The argument specifies alternative low-level mutex routines to be used 1702** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1703** the content of the [sqlite3_mutex_methods] structure before the call to 1704** [sqlite3_config()] returns. ^If SQLite is compiled with 1705** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1706** the entire mutexing subsystem is omitted from the build and hence calls to 1707** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1708** return [SQLITE_ERROR].</dd> 1709** 1710** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1711** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1712** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1713** [sqlite3_mutex_methods] 1714** structure is filled with the currently defined mutex routines.)^ 1715** This option can be used to overload the default mutex allocation 1716** routines with a wrapper used to track mutex usage for performance 1717** profiling or testing, for example. ^If SQLite is compiled with 1718** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1719** the entire mutexing subsystem is omitted from the build and hence calls to 1720** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1721** return [SQLITE_ERROR].</dd> 1722** 1723** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1724** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1725** the default size of lookaside memory on each [database connection]. 1726** The first argument is the 1727** size of each lookaside buffer slot and the second is the number of 1728** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1729** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1730** option to [sqlite3_db_config()] can be used to change the lookaside 1731** configuration on individual connections.)^ </dd> 1732** 1733** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1734** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1735** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1736** the interface to a custom page cache implementation.)^ 1737** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1738** 1739** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1740** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1741** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1742** the current page cache implementation into that object.)^ </dd> 1743** 1744** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1745** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1746** global [error log]. 1747** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1748** function with a call signature of void(*)(void*,int,const char*), 1749** and a pointer to void. ^If the function pointer is not NULL, it is 1750** invoked by [sqlite3_log()] to process each logging event. ^If the 1751** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1752** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1753** passed through as the first parameter to the application-defined logger 1754** function whenever that function is invoked. ^The second parameter to 1755** the logger function is a copy of the first parameter to the corresponding 1756** [sqlite3_log()] call and is intended to be a [result code] or an 1757** [extended result code]. ^The third parameter passed to the logger is 1758** log message after formatting via [sqlite3_snprintf()]. 1759** The SQLite logging interface is not reentrant; the logger function 1760** supplied by the application must not invoke any SQLite interface. 1761** In a multi-threaded application, the application-defined logger 1762** function must be threadsafe. </dd> 1763** 1764** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1765** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1766** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1767** then URI handling is globally disabled.)^ ^If URI handling is globally 1768** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1769** [sqlite3_open16()] or 1770** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1771** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1772** connection is opened. ^If it is globally disabled, filenames are 1773** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1774** database connection is opened. ^(By default, URI handling is globally 1775** disabled. The default value may be changed by compiling with the 1776** [SQLITE_USE_URI] symbol defined.)^ 1777** 1778** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1779** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1780** argument which is interpreted as a boolean in order to enable or disable 1781** the use of covering indices for full table scans in the query optimizer. 1782** ^The default setting is determined 1783** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1784** if that compile-time option is omitted. 1785** The ability to disable the use of covering indices for full table scans 1786** is because some incorrectly coded legacy applications might malfunction 1787** when the optimization is enabled. Providing the ability to 1788** disable the optimization allows the older, buggy application code to work 1789** without change even with newer versions of SQLite. 1790** 1791** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1792** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1793** <dd> These options are obsolete and should not be used by new code. 1794** They are retained for backwards compatibility but are now no-ops. 1795** </dd> 1796** 1797** [[SQLITE_CONFIG_SQLLOG]] 1798** <dt>SQLITE_CONFIG_SQLLOG 1799** <dd>This option is only available if sqlite is compiled with the 1800** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1801** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1802** The second should be of type (void*). The callback is invoked by the library 1803** in three separate circumstances, identified by the value passed as the 1804** fourth parameter. If the fourth parameter is 0, then the database connection 1805** passed as the second argument has just been opened. The third argument 1806** points to a buffer containing the name of the main database file. If the 1807** fourth parameter is 1, then the SQL statement that the third parameter 1808** points to has just been executed. Or, if the fourth parameter is 2, then 1809** the connection being passed as the second parameter is being closed. The 1810** third parameter is passed NULL In this case. An example of using this 1811** configuration option can be seen in the "test_sqllog.c" source file in 1812** the canonical SQLite source tree.</dd> 1813** 1814** [[SQLITE_CONFIG_MMAP_SIZE]] 1815** <dt>SQLITE_CONFIG_MMAP_SIZE 1816** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1817** that are the default mmap size limit (the default setting for 1818** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1819** ^The default setting can be overridden by each database connection using 1820** either the [PRAGMA mmap_size] command, or by using the 1821** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1822** will be silently truncated if necessary so that it does not exceed the 1823** compile-time maximum mmap size set by the 1824** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1825** ^If either argument to this option is negative, then that argument is 1826** changed to its compile-time default. 1827** 1828** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1829** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1830** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1831** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1832** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1833** that specifies the maximum size of the created heap. 1834** 1835** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1836** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1837** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1838** is a pointer to an integer and writes into that integer the number of extra 1839** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1840** The amount of extra space required can change depending on the compiler, 1841** target platform, and SQLite version. 1842** 1843** [[SQLITE_CONFIG_PMASZ]] 1844** <dt>SQLITE_CONFIG_PMASZ 1845** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1846** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1847** sorter to that integer. The default minimum PMA Size is set by the 1848** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1849** to help with sort operations when multithreaded sorting 1850** is enabled (using the [PRAGMA threads] command) and the amount of content 1851** to be sorted exceeds the page size times the minimum of the 1852** [PRAGMA cache_size] setting and this value. 1853** 1854** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1855** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1856** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1857** becomes the [statement journal] spill-to-disk threshold. 1858** [Statement journals] are held in memory until their size (in bytes) 1859** exceeds this threshold, at which point they are written to disk. 1860** Or if the threshold is -1, statement journals are always held 1861** exclusively in memory. 1862** Since many statement journals never become large, setting the spill 1863** threshold to a value such as 64KiB can greatly reduce the amount of 1864** I/O required to support statement rollback. 1865** The default value for this setting is controlled by the 1866** [SQLITE_STMTJRNL_SPILL] compile-time option. 1867** </dl> 1868*/ 1869#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1870#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1871#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1872#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1873#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1874#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1875#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1876#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1877#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1878#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1879#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1880/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1881#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1882#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1883#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1884#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1885#define SQLITE_CONFIG_URI 17 /* int */ 1886#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1887#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1888#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1889#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1890#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1891#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1892#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1893#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1894#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1895 1896/* 1897** CAPI3REF: Database Connection Configuration Options 1898** 1899** These constants are the available integer configuration options that 1900** can be passed as the second argument to the [sqlite3_db_config()] interface. 1901** 1902** New configuration options may be added in future releases of SQLite. 1903** Existing configuration options might be discontinued. Applications 1904** should check the return code from [sqlite3_db_config()] to make sure that 1905** the call worked. ^The [sqlite3_db_config()] interface will return a 1906** non-zero [error code] if a discontinued or unsupported configuration option 1907** is invoked. 1908** 1909** <dl> 1910** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1911** <dd> ^This option takes three additional arguments that determine the 1912** [lookaside memory allocator] configuration for the [database connection]. 1913** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1914** pointer to a memory buffer to use for lookaside memory. 1915** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1916** may be NULL in which case SQLite will allocate the 1917** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1918** size of each lookaside buffer slot. ^The third argument is the number of 1919** slots. The size of the buffer in the first argument must be greater than 1920** or equal to the product of the second and third arguments. The buffer 1921** must be aligned to an 8-byte boundary. ^If the second argument to 1922** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1923** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1924** configuration for a database connection can only be changed when that 1925** connection is not currently using lookaside memory, or in other words 1926** when the "current value" returned by 1927** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1928** Any attempt to change the lookaside memory configuration when lookaside 1929** memory is in use leaves the configuration unchanged and returns 1930** [SQLITE_BUSY].)^</dd> 1931** 1932** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1933** <dd> ^This option is used to enable or disable the enforcement of 1934** [foreign key constraints]. There should be two additional arguments. 1935** The first argument is an integer which is 0 to disable FK enforcement, 1936** positive to enable FK enforcement or negative to leave FK enforcement 1937** unchanged. The second parameter is a pointer to an integer into which 1938** is written 0 or 1 to indicate whether FK enforcement is off or on 1939** following this call. The second parameter may be a NULL pointer, in 1940** which case the FK enforcement setting is not reported back. </dd> 1941** 1942** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1943** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1944** There should be two additional arguments. 1945** The first argument is an integer which is 0 to disable triggers, 1946** positive to enable triggers or negative to leave the setting unchanged. 1947** The second parameter is a pointer to an integer into which 1948** is written 0 or 1 to indicate whether triggers are disabled or enabled 1949** following this call. The second parameter may be a NULL pointer, in 1950** which case the trigger setting is not reported back. </dd> 1951** 1952** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 1953** <dd> ^This option is used to enable or disable the two-argument 1954** version of the [fts3_tokenizer()] function which is part of the 1955** [FTS3] full-text search engine extension. 1956** There should be two additional arguments. 1957** The first argument is an integer which is 0 to disable fts3_tokenizer() or 1958** positive to enable fts3_tokenizer() or negative to leave the setting 1959** unchanged. 1960** The second parameter is a pointer to an integer into which 1961** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 1962** following this call. The second parameter may be a NULL pointer, in 1963** which case the new setting is not reported back. </dd> 1964** 1965** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 1966** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 1967** interface independently of the [load_extension()] SQL function. 1968** The [sqlite3_enable_load_extension()] API enables or disables both the 1969** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 1970** There should be two additional arguments. 1971** When the first argument to this interface is 1, then only the C-API is 1972** enabled and the SQL function remains disabled. If the first argument to 1973** this interface is 0, then both the C-API and the SQL function are disabled. 1974** If the first argument is -1, then no changes are made to state of either the 1975** C-API or the SQL function. 1976** The second parameter is a pointer to an integer into which 1977** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 1978** is disabled or enabled following this call. The second parameter may 1979** be a NULL pointer, in which case the new setting is not reported back. 1980** </dd> 1981** 1982** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 1983** <dd> ^This option is used to change the name of the "main" database 1984** schema. ^The sole argument is a pointer to a constant UTF8 string 1985** which will become the new schema name in place of "main". ^SQLite 1986** does not make a copy of the new main schema name string, so the application 1987** must ensure that the argument passed into this DBCONFIG option is unchanged 1988** until after the database connection closes. 1989** </dd> 1990** 1991** </dl> 1992*/ 1993#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 1994#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1995#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1996#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1997#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 1998#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 1999 2000 2001/* 2002** CAPI3REF: Enable Or Disable Extended Result Codes 2003** METHOD: sqlite3 2004** 2005** ^The sqlite3_extended_result_codes() routine enables or disables the 2006** [extended result codes] feature of SQLite. ^The extended result 2007** codes are disabled by default for historical compatibility. 2008*/ 2009int sqlite3_extended_result_codes(sqlite3*, int onoff); 2010 2011/* 2012** CAPI3REF: Last Insert Rowid 2013** METHOD: sqlite3 2014** 2015** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2016** has a unique 64-bit signed 2017** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2018** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2019** names are not also used by explicitly declared columns. ^If 2020** the table has a column of type [INTEGER PRIMARY KEY] then that column 2021** is another alias for the rowid. 2022** 2023** ^The sqlite3_last_insert_rowid(D) interface returns the [rowid] of the 2024** most recent successful [INSERT] into a rowid table or [virtual table] 2025** on database connection D. 2026** ^Inserts into [WITHOUT ROWID] tables are not recorded. 2027** ^If no successful [INSERT]s into rowid tables 2028** have ever occurred on the database connection D, 2029** then sqlite3_last_insert_rowid(D) returns zero. 2030** 2031** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 2032** method, then this routine will return the [rowid] of the inserted 2033** row as long as the trigger or virtual table method is running. 2034** But once the trigger or virtual table method ends, the value returned 2035** by this routine reverts to what it was before the trigger or virtual 2036** table method began.)^ 2037** 2038** ^An [INSERT] that fails due to a constraint violation is not a 2039** successful [INSERT] and does not change the value returned by this 2040** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2041** and INSERT OR ABORT make no changes to the return value of this 2042** routine when their insertion fails. ^(When INSERT OR REPLACE 2043** encounters a constraint violation, it does not fail. The 2044** INSERT continues to completion after deleting rows that caused 2045** the constraint problem so INSERT OR REPLACE will always change 2046** the return value of this interface.)^ 2047** 2048** ^For the purposes of this routine, an [INSERT] is considered to 2049** be successful even if it is subsequently rolled back. 2050** 2051** This function is accessible to SQL statements via the 2052** [last_insert_rowid() SQL function]. 2053** 2054** If a separate thread performs a new [INSERT] on the same 2055** database connection while the [sqlite3_last_insert_rowid()] 2056** function is running and thus changes the last insert [rowid], 2057** then the value returned by [sqlite3_last_insert_rowid()] is 2058** unpredictable and might not equal either the old or the new 2059** last insert [rowid]. 2060*/ 2061sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2062 2063/* 2064** CAPI3REF: Count The Number Of Rows Modified 2065** METHOD: sqlite3 2066** 2067** ^This function returns the number of rows modified, inserted or 2068** deleted by the most recently completed INSERT, UPDATE or DELETE 2069** statement on the database connection specified by the only parameter. 2070** ^Executing any other type of SQL statement does not modify the value 2071** returned by this function. 2072** 2073** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2074** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2075** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2076** 2077** Changes to a view that are intercepted by 2078** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2079** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2080** DELETE statement run on a view is always zero. Only changes made to real 2081** tables are counted. 2082** 2083** Things are more complicated if the sqlite3_changes() function is 2084** executed while a trigger program is running. This may happen if the 2085** program uses the [changes() SQL function], or if some other callback 2086** function invokes sqlite3_changes() directly. Essentially: 2087** 2088** <ul> 2089** <li> ^(Before entering a trigger program the value returned by 2090** sqlite3_changes() function is saved. After the trigger program 2091** has finished, the original value is restored.)^ 2092** 2093** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2094** statement sets the value returned by sqlite3_changes() 2095** upon completion as normal. Of course, this value will not include 2096** any changes performed by sub-triggers, as the sqlite3_changes() 2097** value will be saved and restored after each sub-trigger has run.)^ 2098** </ul> 2099** 2100** ^This means that if the changes() SQL function (or similar) is used 2101** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2102** returns the value as set when the calling statement began executing. 2103** ^If it is used by the second or subsequent such statement within a trigger 2104** program, the value returned reflects the number of rows modified by the 2105** previous INSERT, UPDATE or DELETE statement within the same trigger. 2106** 2107** See also the [sqlite3_total_changes()] interface, the 2108** [count_changes pragma], and the [changes() SQL function]. 2109** 2110** If a separate thread makes changes on the same database connection 2111** while [sqlite3_changes()] is running then the value returned 2112** is unpredictable and not meaningful. 2113*/ 2114int sqlite3_changes(sqlite3*); 2115 2116/* 2117** CAPI3REF: Total Number Of Rows Modified 2118** METHOD: sqlite3 2119** 2120** ^This function returns the total number of rows inserted, modified or 2121** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2122** since the database connection was opened, including those executed as 2123** part of trigger programs. ^Executing any other type of SQL statement 2124** does not affect the value returned by sqlite3_total_changes(). 2125** 2126** ^Changes made as part of [foreign key actions] are included in the 2127** count, but those made as part of REPLACE constraint resolution are 2128** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2129** are not counted. 2130** 2131** See also the [sqlite3_changes()] interface, the 2132** [count_changes pragma], and the [total_changes() SQL function]. 2133** 2134** If a separate thread makes changes on the same database connection 2135** while [sqlite3_total_changes()] is running then the value 2136** returned is unpredictable and not meaningful. 2137*/ 2138int sqlite3_total_changes(sqlite3*); 2139 2140/* 2141** CAPI3REF: Interrupt A Long-Running Query 2142** METHOD: sqlite3 2143** 2144** ^This function causes any pending database operation to abort and 2145** return at its earliest opportunity. This routine is typically 2146** called in response to a user action such as pressing "Cancel" 2147** or Ctrl-C where the user wants a long query operation to halt 2148** immediately. 2149** 2150** ^It is safe to call this routine from a thread different from the 2151** thread that is currently running the database operation. But it 2152** is not safe to call this routine with a [database connection] that 2153** is closed or might close before sqlite3_interrupt() returns. 2154** 2155** ^If an SQL operation is very nearly finished at the time when 2156** sqlite3_interrupt() is called, then it might not have an opportunity 2157** to be interrupted and might continue to completion. 2158** 2159** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2160** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2161** that is inside an explicit transaction, then the entire transaction 2162** will be rolled back automatically. 2163** 2164** ^The sqlite3_interrupt(D) call is in effect until all currently running 2165** SQL statements on [database connection] D complete. ^Any new SQL statements 2166** that are started after the sqlite3_interrupt() call and before the 2167** running statements reaches zero are interrupted as if they had been 2168** running prior to the sqlite3_interrupt() call. ^New SQL statements 2169** that are started after the running statement count reaches zero are 2170** not effected by the sqlite3_interrupt(). 2171** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2172** SQL statements is a no-op and has no effect on SQL statements 2173** that are started after the sqlite3_interrupt() call returns. 2174** 2175** If the database connection closes while [sqlite3_interrupt()] 2176** is running then bad things will likely happen. 2177*/ 2178void sqlite3_interrupt(sqlite3*); 2179 2180/* 2181** CAPI3REF: Determine If An SQL Statement Is Complete 2182** 2183** These routines are useful during command-line input to determine if the 2184** currently entered text seems to form a complete SQL statement or 2185** if additional input is needed before sending the text into 2186** SQLite for parsing. ^These routines return 1 if the input string 2187** appears to be a complete SQL statement. ^A statement is judged to be 2188** complete if it ends with a semicolon token and is not a prefix of a 2189** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2190** string literals or quoted identifier names or comments are not 2191** independent tokens (they are part of the token in which they are 2192** embedded) and thus do not count as a statement terminator. ^Whitespace 2193** and comments that follow the final semicolon are ignored. 2194** 2195** ^These routines return 0 if the statement is incomplete. ^If a 2196** memory allocation fails, then SQLITE_NOMEM is returned. 2197** 2198** ^These routines do not parse the SQL statements thus 2199** will not detect syntactically incorrect SQL. 2200** 2201** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2202** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2203** automatically by sqlite3_complete16(). If that initialization fails, 2204** then the return value from sqlite3_complete16() will be non-zero 2205** regardless of whether or not the input SQL is complete.)^ 2206** 2207** The input to [sqlite3_complete()] must be a zero-terminated 2208** UTF-8 string. 2209** 2210** The input to [sqlite3_complete16()] must be a zero-terminated 2211** UTF-16 string in native byte order. 2212*/ 2213int sqlite3_complete(const char *sql); 2214int sqlite3_complete16(const void *sql); 2215 2216/* 2217** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2218** KEYWORDS: {busy-handler callback} {busy handler} 2219** METHOD: sqlite3 2220** 2221** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2222** that might be invoked with argument P whenever 2223** an attempt is made to access a database table associated with 2224** [database connection] D when another thread 2225** or process has the table locked. 2226** The sqlite3_busy_handler() interface is used to implement 2227** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2228** 2229** ^If the busy callback is NULL, then [SQLITE_BUSY] 2230** is returned immediately upon encountering the lock. ^If the busy callback 2231** is not NULL, then the callback might be invoked with two arguments. 2232** 2233** ^The first argument to the busy handler is a copy of the void* pointer which 2234** is the third argument to sqlite3_busy_handler(). ^The second argument to 2235** the busy handler callback is the number of times that the busy handler has 2236** been invoked previously for the same locking event. ^If the 2237** busy callback returns 0, then no additional attempts are made to 2238** access the database and [SQLITE_BUSY] is returned 2239** to the application. 2240** ^If the callback returns non-zero, then another attempt 2241** is made to access the database and the cycle repeats. 2242** 2243** The presence of a busy handler does not guarantee that it will be invoked 2244** when there is lock contention. ^If SQLite determines that invoking the busy 2245** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2246** to the application instead of invoking the 2247** busy handler. 2248** Consider a scenario where one process is holding a read lock that 2249** it is trying to promote to a reserved lock and 2250** a second process is holding a reserved lock that it is trying 2251** to promote to an exclusive lock. The first process cannot proceed 2252** because it is blocked by the second and the second process cannot 2253** proceed because it is blocked by the first. If both processes 2254** invoke the busy handlers, neither will make any progress. Therefore, 2255** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2256** will induce the first process to release its read lock and allow 2257** the second process to proceed. 2258** 2259** ^The default busy callback is NULL. 2260** 2261** ^(There can only be a single busy handler defined for each 2262** [database connection]. Setting a new busy handler clears any 2263** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2264** or evaluating [PRAGMA busy_timeout=N] will change the 2265** busy handler and thus clear any previously set busy handler. 2266** 2267** The busy callback should not take any actions which modify the 2268** database connection that invoked the busy handler. In other words, 2269** the busy handler is not reentrant. Any such actions 2270** result in undefined behavior. 2271** 2272** A busy handler must not close the database connection 2273** or [prepared statement] that invoked the busy handler. 2274*/ 2275int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2276 2277/* 2278** CAPI3REF: Set A Busy Timeout 2279** METHOD: sqlite3 2280** 2281** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2282** for a specified amount of time when a table is locked. ^The handler 2283** will sleep multiple times until at least "ms" milliseconds of sleeping 2284** have accumulated. ^After at least "ms" milliseconds of sleeping, 2285** the handler returns 0 which causes [sqlite3_step()] to return 2286** [SQLITE_BUSY]. 2287** 2288** ^Calling this routine with an argument less than or equal to zero 2289** turns off all busy handlers. 2290** 2291** ^(There can only be a single busy handler for a particular 2292** [database connection] at any given moment. If another busy handler 2293** was defined (using [sqlite3_busy_handler()]) prior to calling 2294** this routine, that other busy handler is cleared.)^ 2295** 2296** See also: [PRAGMA busy_timeout] 2297*/ 2298int sqlite3_busy_timeout(sqlite3*, int ms); 2299 2300/* 2301** CAPI3REF: Convenience Routines For Running Queries 2302** METHOD: sqlite3 2303** 2304** This is a legacy interface that is preserved for backwards compatibility. 2305** Use of this interface is not recommended. 2306** 2307** Definition: A <b>result table</b> is memory data structure created by the 2308** [sqlite3_get_table()] interface. A result table records the 2309** complete query results from one or more queries. 2310** 2311** The table conceptually has a number of rows and columns. But 2312** these numbers are not part of the result table itself. These 2313** numbers are obtained separately. Let N be the number of rows 2314** and M be the number of columns. 2315** 2316** A result table is an array of pointers to zero-terminated UTF-8 strings. 2317** There are (N+1)*M elements in the array. The first M pointers point 2318** to zero-terminated strings that contain the names of the columns. 2319** The remaining entries all point to query results. NULL values result 2320** in NULL pointers. All other values are in their UTF-8 zero-terminated 2321** string representation as returned by [sqlite3_column_text()]. 2322** 2323** A result table might consist of one or more memory allocations. 2324** It is not safe to pass a result table directly to [sqlite3_free()]. 2325** A result table should be deallocated using [sqlite3_free_table()]. 2326** 2327** ^(As an example of the result table format, suppose a query result 2328** is as follows: 2329** 2330** <blockquote><pre> 2331** Name | Age 2332** ----------------------- 2333** Alice | 43 2334** Bob | 28 2335** Cindy | 21 2336** </pre></blockquote> 2337** 2338** There are two column (M==2) and three rows (N==3). Thus the 2339** result table has 8 entries. Suppose the result table is stored 2340** in an array names azResult. Then azResult holds this content: 2341** 2342** <blockquote><pre> 2343** azResult[0] = "Name"; 2344** azResult[1] = "Age"; 2345** azResult[2] = "Alice"; 2346** azResult[3] = "43"; 2347** azResult[4] = "Bob"; 2348** azResult[5] = "28"; 2349** azResult[6] = "Cindy"; 2350** azResult[7] = "21"; 2351** </pre></blockquote>)^ 2352** 2353** ^The sqlite3_get_table() function evaluates one or more 2354** semicolon-separated SQL statements in the zero-terminated UTF-8 2355** string of its 2nd parameter and returns a result table to the 2356** pointer given in its 3rd parameter. 2357** 2358** After the application has finished with the result from sqlite3_get_table(), 2359** it must pass the result table pointer to sqlite3_free_table() in order to 2360** release the memory that was malloced. Because of the way the 2361** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2362** function must not try to call [sqlite3_free()] directly. Only 2363** [sqlite3_free_table()] is able to release the memory properly and safely. 2364** 2365** The sqlite3_get_table() interface is implemented as a wrapper around 2366** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2367** to any internal data structures of SQLite. It uses only the public 2368** interface defined here. As a consequence, errors that occur in the 2369** wrapper layer outside of the internal [sqlite3_exec()] call are not 2370** reflected in subsequent calls to [sqlite3_errcode()] or 2371** [sqlite3_errmsg()]. 2372*/ 2373int sqlite3_get_table( 2374 sqlite3 *db, /* An open database */ 2375 const char *zSql, /* SQL to be evaluated */ 2376 char ***pazResult, /* Results of the query */ 2377 int *pnRow, /* Number of result rows written here */ 2378 int *pnColumn, /* Number of result columns written here */ 2379 char **pzErrmsg /* Error msg written here */ 2380); 2381void sqlite3_free_table(char **result); 2382 2383/* 2384** CAPI3REF: Formatted String Printing Functions 2385** 2386** These routines are work-alikes of the "printf()" family of functions 2387** from the standard C library. 2388** These routines understand most of the common K&R formatting options, 2389** plus some additional non-standard formats, detailed below. 2390** Note that some of the more obscure formatting options from recent 2391** C-library standards are omitted from this implementation. 2392** 2393** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2394** results into memory obtained from [sqlite3_malloc()]. 2395** The strings returned by these two routines should be 2396** released by [sqlite3_free()]. ^Both routines return a 2397** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2398** memory to hold the resulting string. 2399** 2400** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2401** the standard C library. The result is written into the 2402** buffer supplied as the second parameter whose size is given by 2403** the first parameter. Note that the order of the 2404** first two parameters is reversed from snprintf().)^ This is an 2405** historical accident that cannot be fixed without breaking 2406** backwards compatibility. ^(Note also that sqlite3_snprintf() 2407** returns a pointer to its buffer instead of the number of 2408** characters actually written into the buffer.)^ We admit that 2409** the number of characters written would be a more useful return 2410** value but we cannot change the implementation of sqlite3_snprintf() 2411** now without breaking compatibility. 2412** 2413** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2414** guarantees that the buffer is always zero-terminated. ^The first 2415** parameter "n" is the total size of the buffer, including space for 2416** the zero terminator. So the longest string that can be completely 2417** written will be n-1 characters. 2418** 2419** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2420** 2421** These routines all implement some additional formatting 2422** options that are useful for constructing SQL statements. 2423** All of the usual printf() formatting options apply. In addition, there 2424** is are "%q", "%Q", "%w" and "%z" options. 2425** 2426** ^(The %q option works like %s in that it substitutes a nul-terminated 2427** string from the argument list. But %q also doubles every '\'' character. 2428** %q is designed for use inside a string literal.)^ By doubling each '\'' 2429** character it escapes that character and allows it to be inserted into 2430** the string. 2431** 2432** For example, assume the string variable zText contains text as follows: 2433** 2434** <blockquote><pre> 2435** char *zText = "It's a happy day!"; 2436** </pre></blockquote> 2437** 2438** One can use this text in an SQL statement as follows: 2439** 2440** <blockquote><pre> 2441** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2442** sqlite3_exec(db, zSQL, 0, 0, 0); 2443** sqlite3_free(zSQL); 2444** </pre></blockquote> 2445** 2446** Because the %q format string is used, the '\'' character in zText 2447** is escaped and the SQL generated is as follows: 2448** 2449** <blockquote><pre> 2450** INSERT INTO table1 VALUES('It''s a happy day!') 2451** </pre></blockquote> 2452** 2453** This is correct. Had we used %s instead of %q, the generated SQL 2454** would have looked like this: 2455** 2456** <blockquote><pre> 2457** INSERT INTO table1 VALUES('It's a happy day!'); 2458** </pre></blockquote> 2459** 2460** This second example is an SQL syntax error. As a general rule you should 2461** always use %q instead of %s when inserting text into a string literal. 2462** 2463** ^(The %Q option works like %q except it also adds single quotes around 2464** the outside of the total string. Additionally, if the parameter in the 2465** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2466** single quotes).)^ So, for example, one could say: 2467** 2468** <blockquote><pre> 2469** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2470** sqlite3_exec(db, zSQL, 0, 0, 0); 2471** sqlite3_free(zSQL); 2472** </pre></blockquote> 2473** 2474** The code above will render a correct SQL statement in the zSQL 2475** variable even if the zText variable is a NULL pointer. 2476** 2477** ^(The "%w" formatting option is like "%q" except that it expects to 2478** be contained within double-quotes instead of single quotes, and it 2479** escapes the double-quote character instead of the single-quote 2480** character.)^ The "%w" formatting option is intended for safely inserting 2481** table and column names into a constructed SQL statement. 2482** 2483** ^(The "%z" formatting option works like "%s" but with the 2484** addition that after the string has been read and copied into 2485** the result, [sqlite3_free()] is called on the input string.)^ 2486*/ 2487char *sqlite3_mprintf(const char*,...); 2488char *sqlite3_vmprintf(const char*, va_list); 2489char *sqlite3_snprintf(int,char*,const char*, ...); 2490char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2491 2492/* 2493** CAPI3REF: Memory Allocation Subsystem 2494** 2495** The SQLite core uses these three routines for all of its own 2496** internal memory allocation needs. "Core" in the previous sentence 2497** does not include operating-system specific VFS implementation. The 2498** Windows VFS uses native malloc() and free() for some operations. 2499** 2500** ^The sqlite3_malloc() routine returns a pointer to a block 2501** of memory at least N bytes in length, where N is the parameter. 2502** ^If sqlite3_malloc() is unable to obtain sufficient free 2503** memory, it returns a NULL pointer. ^If the parameter N to 2504** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2505** a NULL pointer. 2506** 2507** ^The sqlite3_malloc64(N) routine works just like 2508** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2509** of a signed 32-bit integer. 2510** 2511** ^Calling sqlite3_free() with a pointer previously returned 2512** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2513** that it might be reused. ^The sqlite3_free() routine is 2514** a no-op if is called with a NULL pointer. Passing a NULL pointer 2515** to sqlite3_free() is harmless. After being freed, memory 2516** should neither be read nor written. Even reading previously freed 2517** memory might result in a segmentation fault or other severe error. 2518** Memory corruption, a segmentation fault, or other severe error 2519** might result if sqlite3_free() is called with a non-NULL pointer that 2520** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2521** 2522** ^The sqlite3_realloc(X,N) interface attempts to resize a 2523** prior memory allocation X to be at least N bytes. 2524** ^If the X parameter to sqlite3_realloc(X,N) 2525** is a NULL pointer then its behavior is identical to calling 2526** sqlite3_malloc(N). 2527** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2528** negative then the behavior is exactly the same as calling 2529** sqlite3_free(X). 2530** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2531** of at least N bytes in size or NULL if insufficient memory is available. 2532** ^If M is the size of the prior allocation, then min(N,M) bytes 2533** of the prior allocation are copied into the beginning of buffer returned 2534** by sqlite3_realloc(X,N) and the prior allocation is freed. 2535** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2536** prior allocation is not freed. 2537** 2538** ^The sqlite3_realloc64(X,N) interfaces works the same as 2539** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2540** of a 32-bit signed integer. 2541** 2542** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2543** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2544** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2545** ^The value returned by sqlite3_msize(X) might be larger than the number 2546** of bytes requested when X was allocated. ^If X is a NULL pointer then 2547** sqlite3_msize(X) returns zero. If X points to something that is not 2548** the beginning of memory allocation, or if it points to a formerly 2549** valid memory allocation that has now been freed, then the behavior 2550** of sqlite3_msize(X) is undefined and possibly harmful. 2551** 2552** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2553** sqlite3_malloc64(), and sqlite3_realloc64() 2554** is always aligned to at least an 8 byte boundary, or to a 2555** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2556** option is used. 2557** 2558** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2559** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2560** implementation of these routines to be omitted. That capability 2561** is no longer provided. Only built-in memory allocators can be used. 2562** 2563** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2564** the system malloc() and free() directly when converting 2565** filenames between the UTF-8 encoding used by SQLite 2566** and whatever filename encoding is used by the particular Windows 2567** installation. Memory allocation errors were detected, but 2568** they were reported back as [SQLITE_CANTOPEN] or 2569** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2570** 2571** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2572** must be either NULL or else pointers obtained from a prior 2573** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2574** not yet been released. 2575** 2576** The application must not read or write any part of 2577** a block of memory after it has been released using 2578** [sqlite3_free()] or [sqlite3_realloc()]. 2579*/ 2580void *sqlite3_malloc(int); 2581void *sqlite3_malloc64(sqlite3_uint64); 2582void *sqlite3_realloc(void*, int); 2583void *sqlite3_realloc64(void*, sqlite3_uint64); 2584void sqlite3_free(void*); 2585sqlite3_uint64 sqlite3_msize(void*); 2586 2587/* 2588** CAPI3REF: Memory Allocator Statistics 2589** 2590** SQLite provides these two interfaces for reporting on the status 2591** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2592** routines, which form the built-in memory allocation subsystem. 2593** 2594** ^The [sqlite3_memory_used()] routine returns the number of bytes 2595** of memory currently outstanding (malloced but not freed). 2596** ^The [sqlite3_memory_highwater()] routine returns the maximum 2597** value of [sqlite3_memory_used()] since the high-water mark 2598** was last reset. ^The values returned by [sqlite3_memory_used()] and 2599** [sqlite3_memory_highwater()] include any overhead 2600** added by SQLite in its implementation of [sqlite3_malloc()], 2601** but not overhead added by the any underlying system library 2602** routines that [sqlite3_malloc()] may call. 2603** 2604** ^The memory high-water mark is reset to the current value of 2605** [sqlite3_memory_used()] if and only if the parameter to 2606** [sqlite3_memory_highwater()] is true. ^The value returned 2607** by [sqlite3_memory_highwater(1)] is the high-water mark 2608** prior to the reset. 2609*/ 2610sqlite3_int64 sqlite3_memory_used(void); 2611sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2612 2613/* 2614** CAPI3REF: Pseudo-Random Number Generator 2615** 2616** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2617** select random [ROWID | ROWIDs] when inserting new records into a table that 2618** already uses the largest possible [ROWID]. The PRNG is also used for 2619** the build-in random() and randomblob() SQL functions. This interface allows 2620** applications to access the same PRNG for other purposes. 2621** 2622** ^A call to this routine stores N bytes of randomness into buffer P. 2623** ^The P parameter can be a NULL pointer. 2624** 2625** ^If this routine has not been previously called or if the previous 2626** call had N less than one or a NULL pointer for P, then the PRNG is 2627** seeded using randomness obtained from the xRandomness method of 2628** the default [sqlite3_vfs] object. 2629** ^If the previous call to this routine had an N of 1 or more and a 2630** non-NULL P then the pseudo-randomness is generated 2631** internally and without recourse to the [sqlite3_vfs] xRandomness 2632** method. 2633*/ 2634void sqlite3_randomness(int N, void *P); 2635 2636/* 2637** CAPI3REF: Compile-Time Authorization Callbacks 2638** METHOD: sqlite3 2639** 2640** ^This routine registers an authorizer callback with a particular 2641** [database connection], supplied in the first argument. 2642** ^The authorizer callback is invoked as SQL statements are being compiled 2643** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2644** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2645** points during the compilation process, as logic is being created 2646** to perform various actions, the authorizer callback is invoked to 2647** see if those actions are allowed. ^The authorizer callback should 2648** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2649** specific action but allow the SQL statement to continue to be 2650** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2651** rejected with an error. ^If the authorizer callback returns 2652** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2653** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2654** the authorizer will fail with an error message. 2655** 2656** When the callback returns [SQLITE_OK], that means the operation 2657** requested is ok. ^When the callback returns [SQLITE_DENY], the 2658** [sqlite3_prepare_v2()] or equivalent call that triggered the 2659** authorizer will fail with an error message explaining that 2660** access is denied. 2661** 2662** ^The first parameter to the authorizer callback is a copy of the third 2663** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2664** to the callback is an integer [SQLITE_COPY | action code] that specifies 2665** the particular action to be authorized. ^The third through sixth parameters 2666** to the callback are zero-terminated strings that contain additional 2667** details about the action to be authorized. 2668** 2669** ^If the action code is [SQLITE_READ] 2670** and the callback returns [SQLITE_IGNORE] then the 2671** [prepared statement] statement is constructed to substitute 2672** a NULL value in place of the table column that would have 2673** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2674** return can be used to deny an untrusted user access to individual 2675** columns of a table. 2676** ^If the action code is [SQLITE_DELETE] and the callback returns 2677** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2678** [truncate optimization] is disabled and all rows are deleted individually. 2679** 2680** An authorizer is used when [sqlite3_prepare | preparing] 2681** SQL statements from an untrusted source, to ensure that the SQL statements 2682** do not try to access data they are not allowed to see, or that they do not 2683** try to execute malicious statements that damage the database. For 2684** example, an application may allow a user to enter arbitrary 2685** SQL queries for evaluation by a database. But the application does 2686** not want the user to be able to make arbitrary changes to the 2687** database. An authorizer could then be put in place while the 2688** user-entered SQL is being [sqlite3_prepare | prepared] that 2689** disallows everything except [SELECT] statements. 2690** 2691** Applications that need to process SQL from untrusted sources 2692** might also consider lowering resource limits using [sqlite3_limit()] 2693** and limiting database size using the [max_page_count] [PRAGMA] 2694** in addition to using an authorizer. 2695** 2696** ^(Only a single authorizer can be in place on a database connection 2697** at a time. Each call to sqlite3_set_authorizer overrides the 2698** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2699** The authorizer is disabled by default. 2700** 2701** The authorizer callback must not do anything that will modify 2702** the database connection that invoked the authorizer callback. 2703** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2704** database connections for the meaning of "modify" in this paragraph. 2705** 2706** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2707** statement might be re-prepared during [sqlite3_step()] due to a 2708** schema change. Hence, the application should ensure that the 2709** correct authorizer callback remains in place during the [sqlite3_step()]. 2710** 2711** ^Note that the authorizer callback is invoked only during 2712** [sqlite3_prepare()] or its variants. Authorization is not 2713** performed during statement evaluation in [sqlite3_step()], unless 2714** as stated in the previous paragraph, sqlite3_step() invokes 2715** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2716*/ 2717int sqlite3_set_authorizer( 2718 sqlite3*, 2719 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2720 void *pUserData 2721); 2722 2723/* 2724** CAPI3REF: Authorizer Return Codes 2725** 2726** The [sqlite3_set_authorizer | authorizer callback function] must 2727** return either [SQLITE_OK] or one of these two constants in order 2728** to signal SQLite whether or not the action is permitted. See the 2729** [sqlite3_set_authorizer | authorizer documentation] for additional 2730** information. 2731** 2732** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2733** returned from the [sqlite3_vtab_on_conflict()] interface. 2734*/ 2735#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2736#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2737 2738/* 2739** CAPI3REF: Authorizer Action Codes 2740** 2741** The [sqlite3_set_authorizer()] interface registers a callback function 2742** that is invoked to authorize certain SQL statement actions. The 2743** second parameter to the callback is an integer code that specifies 2744** what action is being authorized. These are the integer action codes that 2745** the authorizer callback may be passed. 2746** 2747** These action code values signify what kind of operation is to be 2748** authorized. The 3rd and 4th parameters to the authorization 2749** callback function will be parameters or NULL depending on which of these 2750** codes is used as the second parameter. ^(The 5th parameter to the 2751** authorizer callback is the name of the database ("main", "temp", 2752** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2753** is the name of the inner-most trigger or view that is responsible for 2754** the access attempt or NULL if this access attempt is directly from 2755** top-level SQL code. 2756*/ 2757/******************************************* 3rd ************ 4th ***********/ 2758#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2759#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2760#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2761#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2762#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2763#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2764#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2765#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2766#define SQLITE_DELETE 9 /* Table Name NULL */ 2767#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2768#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2769#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2770#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2771#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2772#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2773#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2774#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2775#define SQLITE_INSERT 18 /* Table Name NULL */ 2776#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2777#define SQLITE_READ 20 /* Table Name Column Name */ 2778#define SQLITE_SELECT 21 /* NULL NULL */ 2779#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2780#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2781#define SQLITE_ATTACH 24 /* Filename NULL */ 2782#define SQLITE_DETACH 25 /* Database Name NULL */ 2783#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2784#define SQLITE_REINDEX 27 /* Index Name NULL */ 2785#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2786#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2787#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2788#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2789#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2790#define SQLITE_COPY 0 /* No longer used */ 2791#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2792 2793/* 2794** CAPI3REF: Tracing And Profiling Functions 2795** METHOD: sqlite3 2796** 2797** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2798** instead of the routines described here. 2799** 2800** These routines register callback functions that can be used for 2801** tracing and profiling the execution of SQL statements. 2802** 2803** ^The callback function registered by sqlite3_trace() is invoked at 2804** various times when an SQL statement is being run by [sqlite3_step()]. 2805** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2806** SQL statement text as the statement first begins executing. 2807** ^(Additional sqlite3_trace() callbacks might occur 2808** as each triggered subprogram is entered. The callbacks for triggers 2809** contain a UTF-8 SQL comment that identifies the trigger.)^ 2810** 2811** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2812** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2813** 2814** ^The callback function registered by sqlite3_profile() is invoked 2815** as each SQL statement finishes. ^The profile callback contains 2816** the original statement text and an estimate of wall-clock time 2817** of how long that statement took to run. ^The profile callback 2818** time is in units of nanoseconds, however the current implementation 2819** is only capable of millisecond resolution so the six least significant 2820** digits in the time are meaningless. Future versions of SQLite 2821** might provide greater resolution on the profiler callback. The 2822** sqlite3_profile() function is considered experimental and is 2823** subject to change in future versions of SQLite. 2824*/ 2825SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2826 void(*xTrace)(void*,const char*), void*); 2827SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2828 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2829 2830/* 2831** CAPI3REF: SQL Trace Event Codes 2832** KEYWORDS: SQLITE_TRACE 2833** 2834** These constants identify classes of events that can be monitored 2835** using the [sqlite3_trace_v2()] tracing logic. The third argument 2836** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2837** the following constants. ^The first argument to the trace callback 2838** is one of the following constants. 2839** 2840** New tracing constants may be added in future releases. 2841** 2842** ^A trace callback has four arguments: xCallback(T,C,P,X). 2843** ^The T argument is one of the integer type codes above. 2844** ^The C argument is a copy of the context pointer passed in as the 2845** fourth argument to [sqlite3_trace_v2()]. 2846** The P and X arguments are pointers whose meanings depend on T. 2847** 2848** <dl> 2849** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2850** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2851** first begins running and possibly at other times during the 2852** execution of the prepared statement, such as at the start of each 2853** trigger subprogram. ^The P argument is a pointer to the 2854** [prepared statement]. ^The X argument is a pointer to a string which 2855** is the unexpanded SQL text of the prepared statement or an SQL comment 2856** that indicates the invocation of a trigger. ^The callback can compute 2857** the same text that would have been returned by the legacy [sqlite3_trace()] 2858** interface by using the X argument when X begins with "--" and invoking 2859** [sqlite3_expanded_sql(P)] otherwise. 2860** 2861** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2862** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2863** information as is provided by the [sqlite3_profile()] callback. 2864** ^The P argument is a pointer to the [prepared statement] and the 2865** X argument points to a 64-bit integer which is the estimated of 2866** the number of nanosecond that the prepared statement took to run. 2867** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2868** 2869** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2870** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2871** statement generates a single row of result. 2872** ^The P argument is a pointer to the [prepared statement] and the 2873** X argument is unused. 2874** 2875** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2876** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2877** connection closes. 2878** ^The P argument is a pointer to the [database connection] object 2879** and the X argument is unused. 2880** </dl> 2881*/ 2882#define SQLITE_TRACE_STMT 0x01 2883#define SQLITE_TRACE_PROFILE 0x02 2884#define SQLITE_TRACE_ROW 0x04 2885#define SQLITE_TRACE_CLOSE 0x08 2886 2887/* 2888** CAPI3REF: SQL Trace Hook 2889** METHOD: sqlite3 2890** 2891** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2892** function X against [database connection] D, using property mask M 2893** and context pointer P. ^If the X callback is 2894** NULL or if the M mask is zero, then tracing is disabled. The 2895** M argument should be the bitwise OR-ed combination of 2896** zero or more [SQLITE_TRACE] constants. 2897** 2898** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2899** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2900** 2901** ^The X callback is invoked whenever any of the events identified by 2902** mask M occur. ^The integer return value from the callback is currently 2903** ignored, though this may change in future releases. Callback 2904** implementations should return zero to ensure future compatibility. 2905** 2906** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2907** ^The T argument is one of the [SQLITE_TRACE] 2908** constants to indicate why the callback was invoked. 2909** ^The C argument is a copy of the context pointer. 2910** The P and X arguments are pointers whose meanings depend on T. 2911** 2912** The sqlite3_trace_v2() interface is intended to replace the legacy 2913** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 2914** are deprecated. 2915*/ 2916int sqlite3_trace_v2( 2917 sqlite3*, 2918 unsigned uMask, 2919 int(*xCallback)(unsigned,void*,void*,void*), 2920 void *pCtx 2921); 2922 2923/* 2924** CAPI3REF: Query Progress Callbacks 2925** METHOD: sqlite3 2926** 2927** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2928** function X to be invoked periodically during long running calls to 2929** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2930** database connection D. An example use for this 2931** interface is to keep a GUI updated during a large query. 2932** 2933** ^The parameter P is passed through as the only parameter to the 2934** callback function X. ^The parameter N is the approximate number of 2935** [virtual machine instructions] that are evaluated between successive 2936** invocations of the callback X. ^If N is less than one then the progress 2937** handler is disabled. 2938** 2939** ^Only a single progress handler may be defined at one time per 2940** [database connection]; setting a new progress handler cancels the 2941** old one. ^Setting parameter X to NULL disables the progress handler. 2942** ^The progress handler is also disabled by setting N to a value less 2943** than 1. 2944** 2945** ^If the progress callback returns non-zero, the operation is 2946** interrupted. This feature can be used to implement a 2947** "Cancel" button on a GUI progress dialog box. 2948** 2949** The progress handler callback must not do anything that will modify 2950** the database connection that invoked the progress handler. 2951** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2952** database connections for the meaning of "modify" in this paragraph. 2953** 2954*/ 2955void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2956 2957/* 2958** CAPI3REF: Opening A New Database Connection 2959** CONSTRUCTOR: sqlite3 2960** 2961** ^These routines open an SQLite database file as specified by the 2962** filename argument. ^The filename argument is interpreted as UTF-8 for 2963** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2964** order for sqlite3_open16(). ^(A [database connection] handle is usually 2965** returned in *ppDb, even if an error occurs. The only exception is that 2966** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2967** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2968** object.)^ ^(If the database is opened (and/or created) successfully, then 2969** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2970** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2971** an English language description of the error following a failure of any 2972** of the sqlite3_open() routines. 2973** 2974** ^The default encoding will be UTF-8 for databases created using 2975** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 2976** created using sqlite3_open16() will be UTF-16 in the native byte order. 2977** 2978** Whether or not an error occurs when it is opened, resources 2979** associated with the [database connection] handle should be released by 2980** passing it to [sqlite3_close()] when it is no longer required. 2981** 2982** The sqlite3_open_v2() interface works like sqlite3_open() 2983** except that it accepts two additional parameters for additional control 2984** over the new database connection. ^(The flags parameter to 2985** sqlite3_open_v2() can take one of 2986** the following three values, optionally combined with the 2987** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2988** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2989** 2990** <dl> 2991** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2992** <dd>The database is opened in read-only mode. If the database does not 2993** already exist, an error is returned.</dd>)^ 2994** 2995** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2996** <dd>The database is opened for reading and writing if possible, or reading 2997** only if the file is write protected by the operating system. In either 2998** case the database must already exist, otherwise an error is returned.</dd>)^ 2999** 3000** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3001** <dd>The database is opened for reading and writing, and is created if 3002** it does not already exist. This is the behavior that is always used for 3003** sqlite3_open() and sqlite3_open16().</dd>)^ 3004** </dl> 3005** 3006** If the 3rd parameter to sqlite3_open_v2() is not one of the 3007** combinations shown above optionally combined with other 3008** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3009** then the behavior is undefined. 3010** 3011** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3012** opens in the multi-thread [threading mode] as long as the single-thread 3013** mode has not been set at compile-time or start-time. ^If the 3014** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3015** in the serialized [threading mode] unless single-thread was 3016** previously selected at compile-time or start-time. 3017** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3018** eligible to use [shared cache mode], regardless of whether or not shared 3019** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3020** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3021** participate in [shared cache mode] even if it is enabled. 3022** 3023** ^The fourth parameter to sqlite3_open_v2() is the name of the 3024** [sqlite3_vfs] object that defines the operating system interface that 3025** the new database connection should use. ^If the fourth parameter is 3026** a NULL pointer then the default [sqlite3_vfs] object is used. 3027** 3028** ^If the filename is ":memory:", then a private, temporary in-memory database 3029** is created for the connection. ^This in-memory database will vanish when 3030** the database connection is closed. Future versions of SQLite might 3031** make use of additional special filenames that begin with the ":" character. 3032** It is recommended that when a database filename actually does begin with 3033** a ":" character you should prefix the filename with a pathname such as 3034** "./" to avoid ambiguity. 3035** 3036** ^If the filename is an empty string, then a private, temporary 3037** on-disk database will be created. ^This private database will be 3038** automatically deleted as soon as the database connection is closed. 3039** 3040** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3041** 3042** ^If [URI filename] interpretation is enabled, and the filename argument 3043** begins with "file:", then the filename is interpreted as a URI. ^URI 3044** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3045** set in the fourth argument to sqlite3_open_v2(), or if it has 3046** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3047** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3048** As of SQLite version 3.7.7, URI filename interpretation is turned off 3049** by default, but future releases of SQLite might enable URI filename 3050** interpretation by default. See "[URI filenames]" for additional 3051** information. 3052** 3053** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3054** authority, then it must be either an empty string or the string 3055** "localhost". ^If the authority is not an empty string or "localhost", an 3056** error is returned to the caller. ^The fragment component of a URI, if 3057** present, is ignored. 3058** 3059** ^SQLite uses the path component of the URI as the name of the disk file 3060** which contains the database. ^If the path begins with a '/' character, 3061** then it is interpreted as an absolute path. ^If the path does not begin 3062** with a '/' (meaning that the authority section is omitted from the URI) 3063** then the path is interpreted as a relative path. 3064** ^(On windows, the first component of an absolute path 3065** is a drive specification (e.g. "C:").)^ 3066** 3067** [[core URI query parameters]] 3068** The query component of a URI may contain parameters that are interpreted 3069** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3070** SQLite and its built-in [VFSes] interpret the 3071** following query parameters: 3072** 3073** <ul> 3074** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3075** a VFS object that provides the operating system interface that should 3076** be used to access the database file on disk. ^If this option is set to 3077** an empty string the default VFS object is used. ^Specifying an unknown 3078** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3079** present, then the VFS specified by the option takes precedence over 3080** the value passed as the fourth parameter to sqlite3_open_v2(). 3081** 3082** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3083** "rwc", or "memory". Attempting to set it to any other value is 3084** an error)^. 3085** ^If "ro" is specified, then the database is opened for read-only 3086** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3087** third argument to sqlite3_open_v2(). ^If the mode option is set to 3088** "rw", then the database is opened for read-write (but not create) 3089** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3090** been set. ^Value "rwc" is equivalent to setting both 3091** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3092** set to "memory" then a pure [in-memory database] that never reads 3093** or writes from disk is used. ^It is an error to specify a value for 3094** the mode parameter that is less restrictive than that specified by 3095** the flags passed in the third parameter to sqlite3_open_v2(). 3096** 3097** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3098** "private". ^Setting it to "shared" is equivalent to setting the 3099** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3100** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3101** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3102** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3103** a URI filename, its value overrides any behavior requested by setting 3104** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3105** 3106** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3107** [powersafe overwrite] property does or does not apply to the 3108** storage media on which the database file resides. 3109** 3110** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3111** which if set disables file locking in rollback journal modes. This 3112** is useful for accessing a database on a filesystem that does not 3113** support locking. Caution: Database corruption might result if two 3114** or more processes write to the same database and any one of those 3115** processes uses nolock=1. 3116** 3117** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3118** parameter that indicates that the database file is stored on 3119** read-only media. ^When immutable is set, SQLite assumes that the 3120** database file cannot be changed, even by a process with higher 3121** privilege, and so the database is opened read-only and all locking 3122** and change detection is disabled. Caution: Setting the immutable 3123** property on a database file that does in fact change can result 3124** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3125** See also: [SQLITE_IOCAP_IMMUTABLE]. 3126** 3127** </ul> 3128** 3129** ^Specifying an unknown parameter in the query component of a URI is not an 3130** error. Future versions of SQLite might understand additional query 3131** parameters. See "[query parameters with special meaning to SQLite]" for 3132** additional information. 3133** 3134** [[URI filename examples]] <h3>URI filename examples</h3> 3135** 3136** <table border="1" align=center cellpadding=5> 3137** <tr><th> URI filenames <th> Results 3138** <tr><td> file:data.db <td> 3139** Open the file "data.db" in the current directory. 3140** <tr><td> file:/home/fred/data.db<br> 3141** file:///home/fred/data.db <br> 3142** file://localhost/home/fred/data.db <br> <td> 3143** Open the database file "/home/fred/data.db". 3144** <tr><td> file://darkstar/home/fred/data.db <td> 3145** An error. "darkstar" is not a recognized authority. 3146** <tr><td style="white-space:nowrap"> 3147** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3148** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3149** C:. Note that the %20 escaping in this example is not strictly 3150** necessary - space characters can be used literally 3151** in URI filenames. 3152** <tr><td> file:data.db?mode=ro&cache=private <td> 3153** Open file "data.db" in the current directory for read-only access. 3154** Regardless of whether or not shared-cache mode is enabled by 3155** default, use a private cache. 3156** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3157** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3158** that uses dot-files in place of posix advisory locking. 3159** <tr><td> file:data.db?mode=readonly <td> 3160** An error. "readonly" is not a valid option for the "mode" parameter. 3161** </table> 3162** 3163** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3164** query components of a URI. A hexadecimal escape sequence consists of a 3165** percent sign - "%" - followed by exactly two hexadecimal digits 3166** specifying an octet value. ^Before the path or query components of a 3167** URI filename are interpreted, they are encoded using UTF-8 and all 3168** hexadecimal escape sequences replaced by a single byte containing the 3169** corresponding octet. If this process generates an invalid UTF-8 encoding, 3170** the results are undefined. 3171** 3172** <b>Note to Windows users:</b> The encoding used for the filename argument 3173** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3174** codepage is currently defined. Filenames containing international 3175** characters must be converted to UTF-8 prior to passing them into 3176** sqlite3_open() or sqlite3_open_v2(). 3177** 3178** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3179** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3180** features that require the use of temporary files may fail. 3181** 3182** See also: [sqlite3_temp_directory] 3183*/ 3184int sqlite3_open( 3185 const char *filename, /* Database filename (UTF-8) */ 3186 sqlite3 **ppDb /* OUT: SQLite db handle */ 3187); 3188int sqlite3_open16( 3189 const void *filename, /* Database filename (UTF-16) */ 3190 sqlite3 **ppDb /* OUT: SQLite db handle */ 3191); 3192int sqlite3_open_v2( 3193 const char *filename, /* Database filename (UTF-8) */ 3194 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3195 int flags, /* Flags */ 3196 const char *zVfs /* Name of VFS module to use */ 3197); 3198 3199/* 3200** CAPI3REF: Obtain Values For URI Parameters 3201** 3202** These are utility routines, useful to VFS implementations, that check 3203** to see if a database file was a URI that contained a specific query 3204** parameter, and if so obtains the value of that query parameter. 3205** 3206** If F is the database filename pointer passed into the xOpen() method of 3207** a VFS implementation when the flags parameter to xOpen() has one or 3208** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3209** P is the name of the query parameter, then 3210** sqlite3_uri_parameter(F,P) returns the value of the P 3211** parameter if it exists or a NULL pointer if P does not appear as a 3212** query parameter on F. If P is a query parameter of F 3213** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3214** a pointer to an empty string. 3215** 3216** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3217** parameter and returns true (1) or false (0) according to the value 3218** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3219** value of query parameter P is one of "yes", "true", or "on" in any 3220** case or if the value begins with a non-zero number. The 3221** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3222** query parameter P is one of "no", "false", or "off" in any case or 3223** if the value begins with a numeric zero. If P is not a query 3224** parameter on F or if the value of P is does not match any of the 3225** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3226** 3227** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3228** 64-bit signed integer and returns that integer, or D if P does not 3229** exist. If the value of P is something other than an integer, then 3230** zero is returned. 3231** 3232** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3233** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3234** is not a database file pathname pointer that SQLite passed into the xOpen 3235** VFS method, then the behavior of this routine is undefined and probably 3236** undesirable. 3237*/ 3238const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3239int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3240sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3241 3242 3243/* 3244** CAPI3REF: Error Codes And Messages 3245** METHOD: sqlite3 3246** 3247** ^If the most recent sqlite3_* API call associated with 3248** [database connection] D failed, then the sqlite3_errcode(D) interface 3249** returns the numeric [result code] or [extended result code] for that 3250** API call. 3251** If the most recent API call was successful, 3252** then the return value from sqlite3_errcode() is undefined. 3253** ^The sqlite3_extended_errcode() 3254** interface is the same except that it always returns the 3255** [extended result code] even when extended result codes are 3256** disabled. 3257** 3258** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3259** text that describes the error, as either UTF-8 or UTF-16 respectively. 3260** ^(Memory to hold the error message string is managed internally. 3261** The application does not need to worry about freeing the result. 3262** However, the error string might be overwritten or deallocated by 3263** subsequent calls to other SQLite interface functions.)^ 3264** 3265** ^The sqlite3_errstr() interface returns the English-language text 3266** that describes the [result code], as UTF-8. 3267** ^(Memory to hold the error message string is managed internally 3268** and must not be freed by the application)^. 3269** 3270** When the serialized [threading mode] is in use, it might be the 3271** case that a second error occurs on a separate thread in between 3272** the time of the first error and the call to these interfaces. 3273** When that happens, the second error will be reported since these 3274** interfaces always report the most recent result. To avoid 3275** this, each thread can obtain exclusive use of the [database connection] D 3276** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3277** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3278** all calls to the interfaces listed here are completed. 3279** 3280** If an interface fails with SQLITE_MISUSE, that means the interface 3281** was invoked incorrectly by the application. In that case, the 3282** error code and message may or may not be set. 3283*/ 3284int sqlite3_errcode(sqlite3 *db); 3285int sqlite3_extended_errcode(sqlite3 *db); 3286const char *sqlite3_errmsg(sqlite3*); 3287const void *sqlite3_errmsg16(sqlite3*); 3288const char *sqlite3_errstr(int); 3289 3290/* 3291** CAPI3REF: Prepared Statement Object 3292** KEYWORDS: {prepared statement} {prepared statements} 3293** 3294** An instance of this object represents a single SQL statement that 3295** has been compiled into binary form and is ready to be evaluated. 3296** 3297** Think of each SQL statement as a separate computer program. The 3298** original SQL text is source code. A prepared statement object 3299** is the compiled object code. All SQL must be converted into a 3300** prepared statement before it can be run. 3301** 3302** The life-cycle of a prepared statement object usually goes like this: 3303** 3304** <ol> 3305** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3306** <li> Bind values to [parameters] using the sqlite3_bind_*() 3307** interfaces. 3308** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3309** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3310** to step 2. Do this zero or more times. 3311** <li> Destroy the object using [sqlite3_finalize()]. 3312** </ol> 3313*/ 3314typedef struct sqlite3_stmt sqlite3_stmt; 3315 3316/* 3317** CAPI3REF: Run-time Limits 3318** METHOD: sqlite3 3319** 3320** ^(This interface allows the size of various constructs to be limited 3321** on a connection by connection basis. The first parameter is the 3322** [database connection] whose limit is to be set or queried. The 3323** second parameter is one of the [limit categories] that define a 3324** class of constructs to be size limited. The third parameter is the 3325** new limit for that construct.)^ 3326** 3327** ^If the new limit is a negative number, the limit is unchanged. 3328** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3329** [limits | hard upper bound] 3330** set at compile-time by a C preprocessor macro called 3331** [limits | SQLITE_MAX_<i>NAME</i>]. 3332** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3333** ^Attempts to increase a limit above its hard upper bound are 3334** silently truncated to the hard upper bound. 3335** 3336** ^Regardless of whether or not the limit was changed, the 3337** [sqlite3_limit()] interface returns the prior value of the limit. 3338** ^Hence, to find the current value of a limit without changing it, 3339** simply invoke this interface with the third parameter set to -1. 3340** 3341** Run-time limits are intended for use in applications that manage 3342** both their own internal database and also databases that are controlled 3343** by untrusted external sources. An example application might be a 3344** web browser that has its own databases for storing history and 3345** separate databases controlled by JavaScript applications downloaded 3346** off the Internet. The internal databases can be given the 3347** large, default limits. Databases managed by external sources can 3348** be given much smaller limits designed to prevent a denial of service 3349** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3350** interface to further control untrusted SQL. The size of the database 3351** created by an untrusted script can be contained using the 3352** [max_page_count] [PRAGMA]. 3353** 3354** New run-time limit categories may be added in future releases. 3355*/ 3356int sqlite3_limit(sqlite3*, int id, int newVal); 3357 3358/* 3359** CAPI3REF: Run-Time Limit Categories 3360** KEYWORDS: {limit category} {*limit categories} 3361** 3362** These constants define various performance limits 3363** that can be lowered at run-time using [sqlite3_limit()]. 3364** The synopsis of the meanings of the various limits is shown below. 3365** Additional information is available at [limits | Limits in SQLite]. 3366** 3367** <dl> 3368** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3369** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3370** 3371** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3372** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3373** 3374** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3375** <dd>The maximum number of columns in a table definition or in the 3376** result set of a [SELECT] or the maximum number of columns in an index 3377** or in an ORDER BY or GROUP BY clause.</dd>)^ 3378** 3379** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3380** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3381** 3382** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3383** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3384** 3385** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3386** <dd>The maximum number of instructions in a virtual machine program 3387** used to implement an SQL statement. This limit is not currently 3388** enforced, though that might be added in some future release of 3389** SQLite.</dd>)^ 3390** 3391** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3392** <dd>The maximum number of arguments on a function.</dd>)^ 3393** 3394** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3395** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3396** 3397** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3398** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3399** <dd>The maximum length of the pattern argument to the [LIKE] or 3400** [GLOB] operators.</dd>)^ 3401** 3402** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3403** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3404** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3405** 3406** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3407** <dd>The maximum depth of recursion for triggers.</dd>)^ 3408** 3409** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3410** <dd>The maximum number of auxiliary worker threads that a single 3411** [prepared statement] may start.</dd>)^ 3412** </dl> 3413*/ 3414#define SQLITE_LIMIT_LENGTH 0 3415#define SQLITE_LIMIT_SQL_LENGTH 1 3416#define SQLITE_LIMIT_COLUMN 2 3417#define SQLITE_LIMIT_EXPR_DEPTH 3 3418#define SQLITE_LIMIT_COMPOUND_SELECT 4 3419#define SQLITE_LIMIT_VDBE_OP 5 3420#define SQLITE_LIMIT_FUNCTION_ARG 6 3421#define SQLITE_LIMIT_ATTACHED 7 3422#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3423#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3424#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3425#define SQLITE_LIMIT_WORKER_THREADS 11 3426 3427/* 3428** CAPI3REF: Compiling An SQL Statement 3429** KEYWORDS: {SQL statement compiler} 3430** METHOD: sqlite3 3431** CONSTRUCTOR: sqlite3_stmt 3432** 3433** To execute an SQL query, it must first be compiled into a byte-code 3434** program using one of these routines. 3435** 3436** The first argument, "db", is a [database connection] obtained from a 3437** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3438** [sqlite3_open16()]. The database connection must not have been closed. 3439** 3440** The second argument, "zSql", is the statement to be compiled, encoded 3441** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 3442** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 3443** use UTF-16. 3444** 3445** ^If the nByte argument is negative, then zSql is read up to the 3446** first zero terminator. ^If nByte is positive, then it is the 3447** number of bytes read from zSql. ^If nByte is zero, then no prepared 3448** statement is generated. 3449** If the caller knows that the supplied string is nul-terminated, then 3450** there is a small performance advantage to passing an nByte parameter that 3451** is the number of bytes in the input string <i>including</i> 3452** the nul-terminator. 3453** 3454** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3455** past the end of the first SQL statement in zSql. These routines only 3456** compile the first statement in zSql, so *pzTail is left pointing to 3457** what remains uncompiled. 3458** 3459** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3460** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3461** to NULL. ^If the input text contains no SQL (if the input is an empty 3462** string or a comment) then *ppStmt is set to NULL. 3463** The calling procedure is responsible for deleting the compiled 3464** SQL statement using [sqlite3_finalize()] after it has finished with it. 3465** ppStmt may not be NULL. 3466** 3467** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3468** otherwise an [error code] is returned. 3469** 3470** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 3471** recommended for all new programs. The two older interfaces are retained 3472** for backwards compatibility, but their use is discouraged. 3473** ^In the "v2" interfaces, the prepared statement 3474** that is returned (the [sqlite3_stmt] object) contains a copy of the 3475** original SQL text. This causes the [sqlite3_step()] interface to 3476** behave differently in three ways: 3477** 3478** <ol> 3479** <li> 3480** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3481** always used to do, [sqlite3_step()] will automatically recompile the SQL 3482** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3483** retries will occur before sqlite3_step() gives up and returns an error. 3484** </li> 3485** 3486** <li> 3487** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3488** [error codes] or [extended error codes]. ^The legacy behavior was that 3489** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3490** and the application would have to make a second call to [sqlite3_reset()] 3491** in order to find the underlying cause of the problem. With the "v2" prepare 3492** interfaces, the underlying reason for the error is returned immediately. 3493** </li> 3494** 3495** <li> 3496** ^If the specific value bound to [parameter | host parameter] in the 3497** WHERE clause might influence the choice of query plan for a statement, 3498** then the statement will be automatically recompiled, as if there had been 3499** a schema change, on the first [sqlite3_step()] call following any change 3500** to the [sqlite3_bind_text | bindings] of that [parameter]. 3501** ^The specific value of WHERE-clause [parameter] might influence the 3502** choice of query plan if the parameter is the left-hand side of a [LIKE] 3503** or [GLOB] operator or if the parameter is compared to an indexed column 3504** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3505** </li> 3506** </ol> 3507*/ 3508int sqlite3_prepare( 3509 sqlite3 *db, /* Database handle */ 3510 const char *zSql, /* SQL statement, UTF-8 encoded */ 3511 int nByte, /* Maximum length of zSql in bytes. */ 3512 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3513 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3514); 3515int sqlite3_prepare_v2( 3516 sqlite3 *db, /* Database handle */ 3517 const char *zSql, /* SQL statement, UTF-8 encoded */ 3518 int nByte, /* Maximum length of zSql in bytes. */ 3519 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3520 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3521); 3522int sqlite3_prepare16( 3523 sqlite3 *db, /* Database handle */ 3524 const void *zSql, /* SQL statement, UTF-16 encoded */ 3525 int nByte, /* Maximum length of zSql in bytes. */ 3526 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3527 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3528); 3529int sqlite3_prepare16_v2( 3530 sqlite3 *db, /* Database handle */ 3531 const void *zSql, /* SQL statement, UTF-16 encoded */ 3532 int nByte, /* Maximum length of zSql in bytes. */ 3533 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3534 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3535); 3536 3537/* 3538** CAPI3REF: Retrieving Statement SQL 3539** METHOD: sqlite3_stmt 3540** 3541** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3542** SQL text used to create [prepared statement] P if P was 3543** created by either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 3544** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3545** string containing the SQL text of prepared statement P with 3546** [bound parameters] expanded. 3547** 3548** ^(For example, if a prepared statement is created using the SQL 3549** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3550** and parameter :xyz is unbound, then sqlite3_sql() will return 3551** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3552** will return "SELECT 2345,NULL".)^ 3553** 3554** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3555** is available to hold the result, or if the result would exceed the 3556** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3557** 3558** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3559** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3560** option causes sqlite3_expanded_sql() to always return NULL. 3561** 3562** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3563** automatically freed when the prepared statement is finalized. 3564** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3565** is obtained from [sqlite3_malloc()] and must be free by the application 3566** by passing it to [sqlite3_free()]. 3567*/ 3568const char *sqlite3_sql(sqlite3_stmt *pStmt); 3569char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3570 3571/* 3572** CAPI3REF: Determine If An SQL Statement Writes The Database 3573** METHOD: sqlite3_stmt 3574** 3575** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3576** and only if the [prepared statement] X makes no direct changes to 3577** the content of the database file. 3578** 3579** Note that [application-defined SQL functions] or 3580** [virtual tables] might change the database indirectly as a side effect. 3581** ^(For example, if an application defines a function "eval()" that 3582** calls [sqlite3_exec()], then the following SQL statement would 3583** change the database file through side-effects: 3584** 3585** <blockquote><pre> 3586** SELECT eval('DELETE FROM t1') FROM t2; 3587** </pre></blockquote> 3588** 3589** But because the [SELECT] statement does not change the database file 3590** directly, sqlite3_stmt_readonly() would still return true.)^ 3591** 3592** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3593** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3594** since the statements themselves do not actually modify the database but 3595** rather they control the timing of when other statements modify the 3596** database. ^The [ATTACH] and [DETACH] statements also cause 3597** sqlite3_stmt_readonly() to return true since, while those statements 3598** change the configuration of a database connection, they do not make 3599** changes to the content of the database files on disk. 3600*/ 3601int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3602 3603/* 3604** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3605** METHOD: sqlite3_stmt 3606** 3607** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3608** [prepared statement] S has been stepped at least once using 3609** [sqlite3_step(S)] but has neither run to completion (returned 3610** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3611** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3612** interface returns false if S is a NULL pointer. If S is not a 3613** NULL pointer and is not a pointer to a valid [prepared statement] 3614** object, then the behavior is undefined and probably undesirable. 3615** 3616** This interface can be used in combination [sqlite3_next_stmt()] 3617** to locate all prepared statements associated with a database 3618** connection that are in need of being reset. This can be used, 3619** for example, in diagnostic routines to search for prepared 3620** statements that are holding a transaction open. 3621*/ 3622int sqlite3_stmt_busy(sqlite3_stmt*); 3623 3624/* 3625** CAPI3REF: Dynamically Typed Value Object 3626** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3627** 3628** SQLite uses the sqlite3_value object to represent all values 3629** that can be stored in a database table. SQLite uses dynamic typing 3630** for the values it stores. ^Values stored in sqlite3_value objects 3631** can be integers, floating point values, strings, BLOBs, or NULL. 3632** 3633** An sqlite3_value object may be either "protected" or "unprotected". 3634** Some interfaces require a protected sqlite3_value. Other interfaces 3635** will accept either a protected or an unprotected sqlite3_value. 3636** Every interface that accepts sqlite3_value arguments specifies 3637** whether or not it requires a protected sqlite3_value. The 3638** [sqlite3_value_dup()] interface can be used to construct a new 3639** protected sqlite3_value from an unprotected sqlite3_value. 3640** 3641** The terms "protected" and "unprotected" refer to whether or not 3642** a mutex is held. An internal mutex is held for a protected 3643** sqlite3_value object but no mutex is held for an unprotected 3644** sqlite3_value object. If SQLite is compiled to be single-threaded 3645** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3646** or if SQLite is run in one of reduced mutex modes 3647** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3648** then there is no distinction between protected and unprotected 3649** sqlite3_value objects and they can be used interchangeably. However, 3650** for maximum code portability it is recommended that applications 3651** still make the distinction between protected and unprotected 3652** sqlite3_value objects even when not strictly required. 3653** 3654** ^The sqlite3_value objects that are passed as parameters into the 3655** implementation of [application-defined SQL functions] are protected. 3656** ^The sqlite3_value object returned by 3657** [sqlite3_column_value()] is unprotected. 3658** Unprotected sqlite3_value objects may only be used with 3659** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3660** The [sqlite3_value_blob | sqlite3_value_type()] family of 3661** interfaces require protected sqlite3_value objects. 3662*/ 3663typedef struct Mem sqlite3_value; 3664 3665/* 3666** CAPI3REF: SQL Function Context Object 3667** 3668** The context in which an SQL function executes is stored in an 3669** sqlite3_context object. ^A pointer to an sqlite3_context object 3670** is always first parameter to [application-defined SQL functions]. 3671** The application-defined SQL function implementation will pass this 3672** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3673** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3674** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3675** and/or [sqlite3_set_auxdata()]. 3676*/ 3677typedef struct sqlite3_context sqlite3_context; 3678 3679/* 3680** CAPI3REF: Binding Values To Prepared Statements 3681** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3682** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3683** METHOD: sqlite3_stmt 3684** 3685** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3686** literals may be replaced by a [parameter] that matches one of following 3687** templates: 3688** 3689** <ul> 3690** <li> ? 3691** <li> ?NNN 3692** <li> :VVV 3693** <li> @VVV 3694** <li> $VVV 3695** </ul> 3696** 3697** In the templates above, NNN represents an integer literal, 3698** and VVV represents an alphanumeric identifier.)^ ^The values of these 3699** parameters (also called "host parameter names" or "SQL parameters") 3700** can be set using the sqlite3_bind_*() routines defined here. 3701** 3702** ^The first argument to the sqlite3_bind_*() routines is always 3703** a pointer to the [sqlite3_stmt] object returned from 3704** [sqlite3_prepare_v2()] or its variants. 3705** 3706** ^The second argument is the index of the SQL parameter to be set. 3707** ^The leftmost SQL parameter has an index of 1. ^When the same named 3708** SQL parameter is used more than once, second and subsequent 3709** occurrences have the same index as the first occurrence. 3710** ^The index for named parameters can be looked up using the 3711** [sqlite3_bind_parameter_index()] API if desired. ^The index 3712** for "?NNN" parameters is the value of NNN. 3713** ^The NNN value must be between 1 and the [sqlite3_limit()] 3714** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3715** 3716** ^The third argument is the value to bind to the parameter. 3717** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3718** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3719** is ignored and the end result is the same as sqlite3_bind_null(). 3720** 3721** ^(In those routines that have a fourth argument, its value is the 3722** number of bytes in the parameter. To be clear: the value is the 3723** number of <u>bytes</u> in the value, not the number of characters.)^ 3724** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3725** is negative, then the length of the string is 3726** the number of bytes up to the first zero terminator. 3727** If the fourth parameter to sqlite3_bind_blob() is negative, then 3728** the behavior is undefined. 3729** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3730** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3731** that parameter must be the byte offset 3732** where the NUL terminator would occur assuming the string were NUL 3733** terminated. If any NUL characters occur at byte offsets less than 3734** the value of the fourth parameter then the resulting string value will 3735** contain embedded NULs. The result of expressions involving strings 3736** with embedded NULs is undefined. 3737** 3738** ^The fifth argument to the BLOB and string binding interfaces 3739** is a destructor used to dispose of the BLOB or 3740** string after SQLite has finished with it. ^The destructor is called 3741** to dispose of the BLOB or string even if the call to bind API fails. 3742** ^If the fifth argument is 3743** the special value [SQLITE_STATIC], then SQLite assumes that the 3744** information is in static, unmanaged space and does not need to be freed. 3745** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3746** SQLite makes its own private copy of the data immediately, before 3747** the sqlite3_bind_*() routine returns. 3748** 3749** ^The sixth argument to sqlite3_bind_text64() must be one of 3750** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3751** to specify the encoding of the text in the third parameter. If 3752** the sixth argument to sqlite3_bind_text64() is not one of the 3753** allowed values shown above, or if the text encoding is different 3754** from the encoding specified by the sixth parameter, then the behavior 3755** is undefined. 3756** 3757** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3758** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3759** (just an integer to hold its size) while it is being processed. 3760** Zeroblobs are intended to serve as placeholders for BLOBs whose 3761** content is later written using 3762** [sqlite3_blob_open | incremental BLOB I/O] routines. 3763** ^A negative value for the zeroblob results in a zero-length BLOB. 3764** 3765** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3766** for the [prepared statement] or with a prepared statement for which 3767** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3768** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3769** routine is passed a [prepared statement] that has been finalized, the 3770** result is undefined and probably harmful. 3771** 3772** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3773** ^Unbound parameters are interpreted as NULL. 3774** 3775** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3776** [error code] if anything goes wrong. 3777** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3778** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3779** [SQLITE_MAX_LENGTH]. 3780** ^[SQLITE_RANGE] is returned if the parameter 3781** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3782** 3783** See also: [sqlite3_bind_parameter_count()], 3784** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3785*/ 3786int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3787int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3788 void(*)(void*)); 3789int sqlite3_bind_double(sqlite3_stmt*, int, double); 3790int sqlite3_bind_int(sqlite3_stmt*, int, int); 3791int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3792int sqlite3_bind_null(sqlite3_stmt*, int); 3793int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3794int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3795int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3796 void(*)(void*), unsigned char encoding); 3797int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3798int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3799int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3800 3801/* 3802** CAPI3REF: Number Of SQL Parameters 3803** METHOD: sqlite3_stmt 3804** 3805** ^This routine can be used to find the number of [SQL parameters] 3806** in a [prepared statement]. SQL parameters are tokens of the 3807** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3808** placeholders for values that are [sqlite3_bind_blob | bound] 3809** to the parameters at a later time. 3810** 3811** ^(This routine actually returns the index of the largest (rightmost) 3812** parameter. For all forms except ?NNN, this will correspond to the 3813** number of unique parameters. If parameters of the ?NNN form are used, 3814** there may be gaps in the list.)^ 3815** 3816** See also: [sqlite3_bind_blob|sqlite3_bind()], 3817** [sqlite3_bind_parameter_name()], and 3818** [sqlite3_bind_parameter_index()]. 3819*/ 3820int sqlite3_bind_parameter_count(sqlite3_stmt*); 3821 3822/* 3823** CAPI3REF: Name Of A Host Parameter 3824** METHOD: sqlite3_stmt 3825** 3826** ^The sqlite3_bind_parameter_name(P,N) interface returns 3827** the name of the N-th [SQL parameter] in the [prepared statement] P. 3828** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3829** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3830** respectively. 3831** In other words, the initial ":" or "$" or "@" or "?" 3832** is included as part of the name.)^ 3833** ^Parameters of the form "?" without a following integer have no name 3834** and are referred to as "nameless" or "anonymous parameters". 3835** 3836** ^The first host parameter has an index of 1, not 0. 3837** 3838** ^If the value N is out of range or if the N-th parameter is 3839** nameless, then NULL is returned. ^The returned string is 3840** always in UTF-8 encoding even if the named parameter was 3841** originally specified as UTF-16 in [sqlite3_prepare16()] or 3842** [sqlite3_prepare16_v2()]. 3843** 3844** See also: [sqlite3_bind_blob|sqlite3_bind()], 3845** [sqlite3_bind_parameter_count()], and 3846** [sqlite3_bind_parameter_index()]. 3847*/ 3848const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3849 3850/* 3851** CAPI3REF: Index Of A Parameter With A Given Name 3852** METHOD: sqlite3_stmt 3853** 3854** ^Return the index of an SQL parameter given its name. ^The 3855** index value returned is suitable for use as the second 3856** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3857** is returned if no matching parameter is found. ^The parameter 3858** name must be given in UTF-8 even if the original statement 3859** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3860** 3861** See also: [sqlite3_bind_blob|sqlite3_bind()], 3862** [sqlite3_bind_parameter_count()], and 3863** [sqlite3_bind_parameter_name()]. 3864*/ 3865int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3866 3867/* 3868** CAPI3REF: Reset All Bindings On A Prepared Statement 3869** METHOD: sqlite3_stmt 3870** 3871** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3872** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3873** ^Use this routine to reset all host parameters to NULL. 3874*/ 3875int sqlite3_clear_bindings(sqlite3_stmt*); 3876 3877/* 3878** CAPI3REF: Number Of Columns In A Result Set 3879** METHOD: sqlite3_stmt 3880** 3881** ^Return the number of columns in the result set returned by the 3882** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3883** statement that does not return data (for example an [UPDATE]). 3884** 3885** See also: [sqlite3_data_count()] 3886*/ 3887int sqlite3_column_count(sqlite3_stmt *pStmt); 3888 3889/* 3890** CAPI3REF: Column Names In A Result Set 3891** METHOD: sqlite3_stmt 3892** 3893** ^These routines return the name assigned to a particular column 3894** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3895** interface returns a pointer to a zero-terminated UTF-8 string 3896** and sqlite3_column_name16() returns a pointer to a zero-terminated 3897** UTF-16 string. ^The first parameter is the [prepared statement] 3898** that implements the [SELECT] statement. ^The second parameter is the 3899** column number. ^The leftmost column is number 0. 3900** 3901** ^The returned string pointer is valid until either the [prepared statement] 3902** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3903** reprepared by the first call to [sqlite3_step()] for a particular run 3904** or until the next call to 3905** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3906** 3907** ^If sqlite3_malloc() fails during the processing of either routine 3908** (for example during a conversion from UTF-8 to UTF-16) then a 3909** NULL pointer is returned. 3910** 3911** ^The name of a result column is the value of the "AS" clause for 3912** that column, if there is an AS clause. If there is no AS clause 3913** then the name of the column is unspecified and may change from 3914** one release of SQLite to the next. 3915*/ 3916const char *sqlite3_column_name(sqlite3_stmt*, int N); 3917const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3918 3919/* 3920** CAPI3REF: Source Of Data In A Query Result 3921** METHOD: sqlite3_stmt 3922** 3923** ^These routines provide a means to determine the database, table, and 3924** table column that is the origin of a particular result column in 3925** [SELECT] statement. 3926** ^The name of the database or table or column can be returned as 3927** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3928** the database name, the _table_ routines return the table name, and 3929** the origin_ routines return the column name. 3930** ^The returned string is valid until the [prepared statement] is destroyed 3931** using [sqlite3_finalize()] or until the statement is automatically 3932** reprepared by the first call to [sqlite3_step()] for a particular run 3933** or until the same information is requested 3934** again in a different encoding. 3935** 3936** ^The names returned are the original un-aliased names of the 3937** database, table, and column. 3938** 3939** ^The first argument to these interfaces is a [prepared statement]. 3940** ^These functions return information about the Nth result column returned by 3941** the statement, where N is the second function argument. 3942** ^The left-most column is column 0 for these routines. 3943** 3944** ^If the Nth column returned by the statement is an expression or 3945** subquery and is not a column value, then all of these functions return 3946** NULL. ^These routine might also return NULL if a memory allocation error 3947** occurs. ^Otherwise, they return the name of the attached database, table, 3948** or column that query result column was extracted from. 3949** 3950** ^As with all other SQLite APIs, those whose names end with "16" return 3951** UTF-16 encoded strings and the other functions return UTF-8. 3952** 3953** ^These APIs are only available if the library was compiled with the 3954** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3955** 3956** If two or more threads call one or more of these routines against the same 3957** prepared statement and column at the same time then the results are 3958** undefined. 3959** 3960** If two or more threads call one or more 3961** [sqlite3_column_database_name | column metadata interfaces] 3962** for the same [prepared statement] and result column 3963** at the same time then the results are undefined. 3964*/ 3965const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3966const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3967const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3968const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3969const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3970const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3971 3972/* 3973** CAPI3REF: Declared Datatype Of A Query Result 3974** METHOD: sqlite3_stmt 3975** 3976** ^(The first parameter is a [prepared statement]. 3977** If this statement is a [SELECT] statement and the Nth column of the 3978** returned result set of that [SELECT] is a table column (not an 3979** expression or subquery) then the declared type of the table 3980** column is returned.)^ ^If the Nth column of the result set is an 3981** expression or subquery, then a NULL pointer is returned. 3982** ^The returned string is always UTF-8 encoded. 3983** 3984** ^(For example, given the database schema: 3985** 3986** CREATE TABLE t1(c1 VARIANT); 3987** 3988** and the following statement to be compiled: 3989** 3990** SELECT c1 + 1, c1 FROM t1; 3991** 3992** this routine would return the string "VARIANT" for the second result 3993** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3994** 3995** ^SQLite uses dynamic run-time typing. ^So just because a column 3996** is declared to contain a particular type does not mean that the 3997** data stored in that column is of the declared type. SQLite is 3998** strongly typed, but the typing is dynamic not static. ^Type 3999** is associated with individual values, not with the containers 4000** used to hold those values. 4001*/ 4002const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4003const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4004 4005/* 4006** CAPI3REF: Evaluate An SQL Statement 4007** METHOD: sqlite3_stmt 4008** 4009** After a [prepared statement] has been prepared using either 4010** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 4011** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4012** must be called one or more times to evaluate the statement. 4013** 4014** The details of the behavior of the sqlite3_step() interface depend 4015** on whether the statement was prepared using the newer "v2" interface 4016** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 4017** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4018** new "v2" interface is recommended for new applications but the legacy 4019** interface will continue to be supported. 4020** 4021** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4022** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4023** ^With the "v2" interface, any of the other [result codes] or 4024** [extended result codes] might be returned as well. 4025** 4026** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4027** database locks it needs to do its job. ^If the statement is a [COMMIT] 4028** or occurs outside of an explicit transaction, then you can retry the 4029** statement. If the statement is not a [COMMIT] and occurs within an 4030** explicit transaction then you should rollback the transaction before 4031** continuing. 4032** 4033** ^[SQLITE_DONE] means that the statement has finished executing 4034** successfully. sqlite3_step() should not be called again on this virtual 4035** machine without first calling [sqlite3_reset()] to reset the virtual 4036** machine back to its initial state. 4037** 4038** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4039** is returned each time a new row of data is ready for processing by the 4040** caller. The values may be accessed using the [column access functions]. 4041** sqlite3_step() is called again to retrieve the next row of data. 4042** 4043** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4044** violation) has occurred. sqlite3_step() should not be called again on 4045** the VM. More information may be found by calling [sqlite3_errmsg()]. 4046** ^With the legacy interface, a more specific error code (for example, 4047** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4048** can be obtained by calling [sqlite3_reset()] on the 4049** [prepared statement]. ^In the "v2" interface, 4050** the more specific error code is returned directly by sqlite3_step(). 4051** 4052** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4053** Perhaps it was called on a [prepared statement] that has 4054** already been [sqlite3_finalize | finalized] or on one that had 4055** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4056** be the case that the same database connection is being used by two or 4057** more threads at the same moment in time. 4058** 4059** For all versions of SQLite up to and including 3.6.23.1, a call to 4060** [sqlite3_reset()] was required after sqlite3_step() returned anything 4061** other than [SQLITE_ROW] before any subsequent invocation of 4062** sqlite3_step(). Failure to reset the prepared statement using 4063** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4064** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4065** sqlite3_step() began 4066** calling [sqlite3_reset()] automatically in this circumstance rather 4067** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4068** break because any application that ever receives an SQLITE_MISUSE error 4069** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4070** can be used to restore the legacy behavior. 4071** 4072** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4073** API always returns a generic error code, [SQLITE_ERROR], following any 4074** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4075** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4076** specific [error codes] that better describes the error. 4077** We admit that this is a goofy design. The problem has been fixed 4078** with the "v2" interface. If you prepare all of your SQL statements 4079** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 4080** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4081** then the more specific [error codes] are returned directly 4082** by sqlite3_step(). The use of the "v2" interface is recommended. 4083*/ 4084int sqlite3_step(sqlite3_stmt*); 4085 4086/* 4087** CAPI3REF: Number of columns in a result set 4088** METHOD: sqlite3_stmt 4089** 4090** ^The sqlite3_data_count(P) interface returns the number of columns in the 4091** current row of the result set of [prepared statement] P. 4092** ^If prepared statement P does not have results ready to return 4093** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4094** interfaces) then sqlite3_data_count(P) returns 0. 4095** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4096** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4097** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4098** will return non-zero if previous call to [sqlite3_step](P) returned 4099** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4100** where it always returns zero since each step of that multi-step 4101** pragma returns 0 columns of data. 4102** 4103** See also: [sqlite3_column_count()] 4104*/ 4105int sqlite3_data_count(sqlite3_stmt *pStmt); 4106 4107/* 4108** CAPI3REF: Fundamental Datatypes 4109** KEYWORDS: SQLITE_TEXT 4110** 4111** ^(Every value in SQLite has one of five fundamental datatypes: 4112** 4113** <ul> 4114** <li> 64-bit signed integer 4115** <li> 64-bit IEEE floating point number 4116** <li> string 4117** <li> BLOB 4118** <li> NULL 4119** </ul>)^ 4120** 4121** These constants are codes for each of those types. 4122** 4123** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4124** for a completely different meaning. Software that links against both 4125** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4126** SQLITE_TEXT. 4127*/ 4128#define SQLITE_INTEGER 1 4129#define SQLITE_FLOAT 2 4130#define SQLITE_BLOB 4 4131#define SQLITE_NULL 5 4132#ifdef SQLITE_TEXT 4133# undef SQLITE_TEXT 4134#else 4135# define SQLITE_TEXT 3 4136#endif 4137#define SQLITE3_TEXT 3 4138 4139/* 4140** CAPI3REF: Result Values From A Query 4141** KEYWORDS: {column access functions} 4142** METHOD: sqlite3_stmt 4143** 4144** ^These routines return information about a single column of the current 4145** result row of a query. ^In every case the first argument is a pointer 4146** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4147** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4148** and the second argument is the index of the column for which information 4149** should be returned. ^The leftmost column of the result set has the index 0. 4150** ^The number of columns in the result can be determined using 4151** [sqlite3_column_count()]. 4152** 4153** If the SQL statement does not currently point to a valid row, or if the 4154** column index is out of range, the result is undefined. 4155** These routines may only be called when the most recent call to 4156** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4157** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4158** If any of these routines are called after [sqlite3_reset()] or 4159** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4160** something other than [SQLITE_ROW], the results are undefined. 4161** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4162** are called from a different thread while any of these routines 4163** are pending, then the results are undefined. 4164** 4165** ^The sqlite3_column_type() routine returns the 4166** [SQLITE_INTEGER | datatype code] for the initial data type 4167** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4168** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 4169** returned by sqlite3_column_type() is only meaningful if no type 4170** conversions have occurred as described below. After a type conversion, 4171** the value returned by sqlite3_column_type() is undefined. Future 4172** versions of SQLite may change the behavior of sqlite3_column_type() 4173** following a type conversion. 4174** 4175** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4176** routine returns the number of bytes in that BLOB or string. 4177** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4178** the string to UTF-8 and then returns the number of bytes. 4179** ^If the result is a numeric value then sqlite3_column_bytes() uses 4180** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4181** the number of bytes in that string. 4182** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4183** 4184** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4185** routine returns the number of bytes in that BLOB or string. 4186** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4187** the string to UTF-16 and then returns the number of bytes. 4188** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4189** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4190** the number of bytes in that string. 4191** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4192** 4193** ^The values returned by [sqlite3_column_bytes()] and 4194** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4195** of the string. ^For clarity: the values returned by 4196** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4197** bytes in the string, not the number of characters. 4198** 4199** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4200** even empty strings, are always zero-terminated. ^The return 4201** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4202** 4203** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4204** [unprotected sqlite3_value] object. In a multithreaded environment, 4205** an unprotected sqlite3_value object may only be used safely with 4206** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4207** If the [unprotected sqlite3_value] object returned by 4208** [sqlite3_column_value()] is used in any other way, including calls 4209** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4210** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4211** 4212** These routines attempt to convert the value where appropriate. ^For 4213** example, if the internal representation is FLOAT and a text result 4214** is requested, [sqlite3_snprintf()] is used internally to perform the 4215** conversion automatically. ^(The following table details the conversions 4216** that are applied: 4217** 4218** <blockquote> 4219** <table border="1"> 4220** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4221** 4222** <tr><td> NULL <td> INTEGER <td> Result is 0 4223** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4224** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4225** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4226** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4227** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4228** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4229** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4230** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4231** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4232** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4233** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4234** <tr><td> TEXT <td> BLOB <td> No change 4235** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4236** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4237** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4238** </table> 4239** </blockquote>)^ 4240** 4241** Note that when type conversions occur, pointers returned by prior 4242** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4243** sqlite3_column_text16() may be invalidated. 4244** Type conversions and pointer invalidations might occur 4245** in the following cases: 4246** 4247** <ul> 4248** <li> The initial content is a BLOB and sqlite3_column_text() or 4249** sqlite3_column_text16() is called. A zero-terminator might 4250** need to be added to the string.</li> 4251** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4252** sqlite3_column_text16() is called. The content must be converted 4253** to UTF-16.</li> 4254** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4255** sqlite3_column_text() is called. The content must be converted 4256** to UTF-8.</li> 4257** </ul> 4258** 4259** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4260** not invalidate a prior pointer, though of course the content of the buffer 4261** that the prior pointer references will have been modified. Other kinds 4262** of conversion are done in place when it is possible, but sometimes they 4263** are not possible and in those cases prior pointers are invalidated. 4264** 4265** The safest policy is to invoke these routines 4266** in one of the following ways: 4267** 4268** <ul> 4269** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4270** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4271** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4272** </ul> 4273** 4274** In other words, you should call sqlite3_column_text(), 4275** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4276** into the desired format, then invoke sqlite3_column_bytes() or 4277** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4278** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4279** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4280** with calls to sqlite3_column_bytes(). 4281** 4282** ^The pointers returned are valid until a type conversion occurs as 4283** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4284** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4285** and BLOBs is freed automatically. Do <em>not</em> pass the pointers returned 4286** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4287** [sqlite3_free()]. 4288** 4289** ^(If a memory allocation error occurs during the evaluation of any 4290** of these routines, a default value is returned. The default value 4291** is either the integer 0, the floating point number 0.0, or a NULL 4292** pointer. Subsequent calls to [sqlite3_errcode()] will return 4293** [SQLITE_NOMEM].)^ 4294*/ 4295const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4296int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4297int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4298double sqlite3_column_double(sqlite3_stmt*, int iCol); 4299int sqlite3_column_int(sqlite3_stmt*, int iCol); 4300sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4301const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4302const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4303int sqlite3_column_type(sqlite3_stmt*, int iCol); 4304sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4305 4306/* 4307** CAPI3REF: Destroy A Prepared Statement Object 4308** DESTRUCTOR: sqlite3_stmt 4309** 4310** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4311** ^If the most recent evaluation of the statement encountered no errors 4312** or if the statement is never been evaluated, then sqlite3_finalize() returns 4313** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4314** sqlite3_finalize(S) returns the appropriate [error code] or 4315** [extended error code]. 4316** 4317** ^The sqlite3_finalize(S) routine can be called at any point during 4318** the life cycle of [prepared statement] S: 4319** before statement S is ever evaluated, after 4320** one or more calls to [sqlite3_reset()], or after any call 4321** to [sqlite3_step()] regardless of whether or not the statement has 4322** completed execution. 4323** 4324** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4325** 4326** The application must finalize every [prepared statement] in order to avoid 4327** resource leaks. It is a grievous error for the application to try to use 4328** a prepared statement after it has been finalized. Any use of a prepared 4329** statement after it has been finalized can result in undefined and 4330** undesirable behavior such as segfaults and heap corruption. 4331*/ 4332int sqlite3_finalize(sqlite3_stmt *pStmt); 4333 4334/* 4335** CAPI3REF: Reset A Prepared Statement Object 4336** METHOD: sqlite3_stmt 4337** 4338** The sqlite3_reset() function is called to reset a [prepared statement] 4339** object back to its initial state, ready to be re-executed. 4340** ^Any SQL statement variables that had values bound to them using 4341** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4342** Use [sqlite3_clear_bindings()] to reset the bindings. 4343** 4344** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4345** back to the beginning of its program. 4346** 4347** ^If the most recent call to [sqlite3_step(S)] for the 4348** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4349** or if [sqlite3_step(S)] has never before been called on S, 4350** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4351** 4352** ^If the most recent call to [sqlite3_step(S)] for the 4353** [prepared statement] S indicated an error, then 4354** [sqlite3_reset(S)] returns an appropriate [error code]. 4355** 4356** ^The [sqlite3_reset(S)] interface does not change the values 4357** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4358*/ 4359int sqlite3_reset(sqlite3_stmt *pStmt); 4360 4361/* 4362** CAPI3REF: Create Or Redefine SQL Functions 4363** KEYWORDS: {function creation routines} 4364** KEYWORDS: {application-defined SQL function} 4365** KEYWORDS: {application-defined SQL functions} 4366** METHOD: sqlite3 4367** 4368** ^These functions (collectively known as "function creation routines") 4369** are used to add SQL functions or aggregates or to redefine the behavior 4370** of existing SQL functions or aggregates. The only differences between 4371** these routines are the text encoding expected for 4372** the second parameter (the name of the function being created) 4373** and the presence or absence of a destructor callback for 4374** the application data pointer. 4375** 4376** ^The first parameter is the [database connection] to which the SQL 4377** function is to be added. ^If an application uses more than one database 4378** connection then application-defined SQL functions must be added 4379** to each database connection separately. 4380** 4381** ^The second parameter is the name of the SQL function to be created or 4382** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4383** representation, exclusive of the zero-terminator. ^Note that the name 4384** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4385** ^Any attempt to create a function with a longer name 4386** will result in [SQLITE_MISUSE] being returned. 4387** 4388** ^The third parameter (nArg) 4389** is the number of arguments that the SQL function or 4390** aggregate takes. ^If this parameter is -1, then the SQL function or 4391** aggregate may take any number of arguments between 0 and the limit 4392** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4393** parameter is less than -1 or greater than 127 then the behavior is 4394** undefined. 4395** 4396** ^The fourth parameter, eTextRep, specifies what 4397** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4398** its parameters. The application should set this parameter to 4399** [SQLITE_UTF16LE] if the function implementation invokes 4400** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4401** implementation invokes [sqlite3_value_text16be()] on an input, or 4402** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4403** otherwise. ^The same SQL function may be registered multiple times using 4404** different preferred text encodings, with different implementations for 4405** each encoding. 4406** ^When multiple implementations of the same function are available, SQLite 4407** will pick the one that involves the least amount of data conversion. 4408** 4409** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4410** to signal that the function will always return the same result given 4411** the same inputs within a single SQL statement. Most SQL functions are 4412** deterministic. The built-in [random()] SQL function is an example of a 4413** function that is not deterministic. The SQLite query planner is able to 4414** perform additional optimizations on deterministic functions, so use 4415** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4416** 4417** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4418** function can gain access to this pointer using [sqlite3_user_data()].)^ 4419** 4420** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4421** pointers to C-language functions that implement the SQL function or 4422** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4423** callback only; NULL pointers must be passed as the xStep and xFinal 4424** parameters. ^An aggregate SQL function requires an implementation of xStep 4425** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4426** SQL function or aggregate, pass NULL pointers for all three function 4427** callbacks. 4428** 4429** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4430** then it is destructor for the application data pointer. 4431** The destructor is invoked when the function is deleted, either by being 4432** overloaded or when the database connection closes.)^ 4433** ^The destructor is also invoked if the call to 4434** sqlite3_create_function_v2() fails. 4435** ^When the destructor callback of the tenth parameter is invoked, it 4436** is passed a single argument which is a copy of the application data 4437** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4438** 4439** ^It is permitted to register multiple implementations of the same 4440** functions with the same name but with either differing numbers of 4441** arguments or differing preferred text encodings. ^SQLite will use 4442** the implementation that most closely matches the way in which the 4443** SQL function is used. ^A function implementation with a non-negative 4444** nArg parameter is a better match than a function implementation with 4445** a negative nArg. ^A function where the preferred text encoding 4446** matches the database encoding is a better 4447** match than a function where the encoding is different. 4448** ^A function where the encoding difference is between UTF16le and UTF16be 4449** is a closer match than a function where the encoding difference is 4450** between UTF8 and UTF16. 4451** 4452** ^Built-in functions may be overloaded by new application-defined functions. 4453** 4454** ^An application-defined function is permitted to call other 4455** SQLite interfaces. However, such calls must not 4456** close the database connection nor finalize or reset the prepared 4457** statement in which the function is running. 4458*/ 4459int sqlite3_create_function( 4460 sqlite3 *db, 4461 const char *zFunctionName, 4462 int nArg, 4463 int eTextRep, 4464 void *pApp, 4465 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4466 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4467 void (*xFinal)(sqlite3_context*) 4468); 4469int sqlite3_create_function16( 4470 sqlite3 *db, 4471 const void *zFunctionName, 4472 int nArg, 4473 int eTextRep, 4474 void *pApp, 4475 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4476 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4477 void (*xFinal)(sqlite3_context*) 4478); 4479int sqlite3_create_function_v2( 4480 sqlite3 *db, 4481 const char *zFunctionName, 4482 int nArg, 4483 int eTextRep, 4484 void *pApp, 4485 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4486 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4487 void (*xFinal)(sqlite3_context*), 4488 void(*xDestroy)(void*) 4489); 4490 4491/* 4492** CAPI3REF: Text Encodings 4493** 4494** These constant define integer codes that represent the various 4495** text encodings supported by SQLite. 4496*/ 4497#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4498#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4499#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4500#define SQLITE_UTF16 4 /* Use native byte order */ 4501#define SQLITE_ANY 5 /* Deprecated */ 4502#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4503 4504/* 4505** CAPI3REF: Function Flags 4506** 4507** These constants may be ORed together with the 4508** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4509** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4510** [sqlite3_create_function_v2()]. 4511*/ 4512#define SQLITE_DETERMINISTIC 0x800 4513 4514/* 4515** CAPI3REF: Deprecated Functions 4516** DEPRECATED 4517** 4518** These functions are [deprecated]. In order to maintain 4519** backwards compatibility with older code, these functions continue 4520** to be supported. However, new applications should avoid 4521** the use of these functions. To encourage programmers to avoid 4522** these functions, we will not explain what they do. 4523*/ 4524#ifndef SQLITE_OMIT_DEPRECATED 4525SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4526SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4527SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4528SQLITE_DEPRECATED int sqlite3_global_recover(void); 4529SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4530SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4531 void*,sqlite3_int64); 4532#endif 4533 4534/* 4535** CAPI3REF: Obtaining SQL Values 4536** METHOD: sqlite3_value 4537** 4538** The C-language implementation of SQL functions and aggregates uses 4539** this set of interface routines to access the parameter values on 4540** the function or aggregate. 4541** 4542** The xFunc (for scalar functions) or xStep (for aggregates) parameters 4543** to [sqlite3_create_function()] and [sqlite3_create_function16()] 4544** define callbacks that implement the SQL functions and aggregates. 4545** The 3rd parameter to these callbacks is an array of pointers to 4546** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 4547** each parameter to the SQL function. These routines are used to 4548** extract values from the [sqlite3_value] objects. 4549** 4550** These routines work only with [protected sqlite3_value] objects. 4551** Any attempt to use these routines on an [unprotected sqlite3_value] 4552** object results in undefined behavior. 4553** 4554** ^These routines work just like the corresponding [column access functions] 4555** except that these routines take a single [protected sqlite3_value] object 4556** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4557** 4558** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4559** in the native byte-order of the host machine. ^The 4560** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4561** extract UTF-16 strings as big-endian and little-endian respectively. 4562** 4563** ^(The sqlite3_value_numeric_type() interface attempts to apply 4564** numeric affinity to the value. This means that an attempt is 4565** made to convert the value to an integer or floating point. If 4566** such a conversion is possible without loss of information (in other 4567** words, if the value is a string that looks like a number) 4568** then the conversion is performed. Otherwise no conversion occurs. 4569** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4570** 4571** Please pay particular attention to the fact that the pointer returned 4572** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4573** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4574** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4575** or [sqlite3_value_text16()]. 4576** 4577** These routines must be called from the same thread as 4578** the SQL function that supplied the [sqlite3_value*] parameters. 4579*/ 4580const void *sqlite3_value_blob(sqlite3_value*); 4581int sqlite3_value_bytes(sqlite3_value*); 4582int sqlite3_value_bytes16(sqlite3_value*); 4583double sqlite3_value_double(sqlite3_value*); 4584int sqlite3_value_int(sqlite3_value*); 4585sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4586const unsigned char *sqlite3_value_text(sqlite3_value*); 4587const void *sqlite3_value_text16(sqlite3_value*); 4588const void *sqlite3_value_text16le(sqlite3_value*); 4589const void *sqlite3_value_text16be(sqlite3_value*); 4590int sqlite3_value_type(sqlite3_value*); 4591int sqlite3_value_numeric_type(sqlite3_value*); 4592 4593/* 4594** CAPI3REF: Finding The Subtype Of SQL Values 4595** METHOD: sqlite3_value 4596** 4597** The sqlite3_value_subtype(V) function returns the subtype for 4598** an [application-defined SQL function] argument V. The subtype 4599** information can be used to pass a limited amount of context from 4600** one SQL function to another. Use the [sqlite3_result_subtype()] 4601** routine to set the subtype for the return value of an SQL function. 4602** 4603** SQLite makes no use of subtype itself. It merely passes the subtype 4604** from the result of one [application-defined SQL function] into the 4605** input of another. 4606*/ 4607unsigned int sqlite3_value_subtype(sqlite3_value*); 4608 4609/* 4610** CAPI3REF: Copy And Free SQL Values 4611** METHOD: sqlite3_value 4612** 4613** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4614** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4615** is a [protected sqlite3_value] object even if the input is not. 4616** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4617** memory allocation fails. 4618** 4619** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4620** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4621** then sqlite3_value_free(V) is a harmless no-op. 4622*/ 4623sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4624void sqlite3_value_free(sqlite3_value*); 4625 4626/* 4627** CAPI3REF: Obtain Aggregate Function Context 4628** METHOD: sqlite3_context 4629** 4630** Implementations of aggregate SQL functions use this 4631** routine to allocate memory for storing their state. 4632** 4633** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4634** for a particular aggregate function, SQLite 4635** allocates N of memory, zeroes out that memory, and returns a pointer 4636** to the new memory. ^On second and subsequent calls to 4637** sqlite3_aggregate_context() for the same aggregate function instance, 4638** the same buffer is returned. Sqlite3_aggregate_context() is normally 4639** called once for each invocation of the xStep callback and then one 4640** last time when the xFinal callback is invoked. ^(When no rows match 4641** an aggregate query, the xStep() callback of the aggregate function 4642** implementation is never called and xFinal() is called exactly once. 4643** In those cases, sqlite3_aggregate_context() might be called for the 4644** first time from within xFinal().)^ 4645** 4646** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4647** when first called if N is less than or equal to zero or if a memory 4648** allocate error occurs. 4649** 4650** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4651** determined by the N parameter on first successful call. Changing the 4652** value of N in subsequent call to sqlite3_aggregate_context() within 4653** the same aggregate function instance will not resize the memory 4654** allocation.)^ Within the xFinal callback, it is customary to set 4655** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4656** pointless memory allocations occur. 4657** 4658** ^SQLite automatically frees the memory allocated by 4659** sqlite3_aggregate_context() when the aggregate query concludes. 4660** 4661** The first parameter must be a copy of the 4662** [sqlite3_context | SQL function context] that is the first parameter 4663** to the xStep or xFinal callback routine that implements the aggregate 4664** function. 4665** 4666** This routine must be called from the same thread in which 4667** the aggregate SQL function is running. 4668*/ 4669void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4670 4671/* 4672** CAPI3REF: User Data For Functions 4673** METHOD: sqlite3_context 4674** 4675** ^The sqlite3_user_data() interface returns a copy of 4676** the pointer that was the pUserData parameter (the 5th parameter) 4677** of the [sqlite3_create_function()] 4678** and [sqlite3_create_function16()] routines that originally 4679** registered the application defined function. 4680** 4681** This routine must be called from the same thread in which 4682** the application-defined function is running. 4683*/ 4684void *sqlite3_user_data(sqlite3_context*); 4685 4686/* 4687** CAPI3REF: Database Connection For Functions 4688** METHOD: sqlite3_context 4689** 4690** ^The sqlite3_context_db_handle() interface returns a copy of 4691** the pointer to the [database connection] (the 1st parameter) 4692** of the [sqlite3_create_function()] 4693** and [sqlite3_create_function16()] routines that originally 4694** registered the application defined function. 4695*/ 4696sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4697 4698/* 4699** CAPI3REF: Function Auxiliary Data 4700** METHOD: sqlite3_context 4701** 4702** These functions may be used by (non-aggregate) SQL functions to 4703** associate metadata with argument values. If the same value is passed to 4704** multiple invocations of the same SQL function during query execution, under 4705** some circumstances the associated metadata may be preserved. An example 4706** of where this might be useful is in a regular-expression matching 4707** function. The compiled version of the regular expression can be stored as 4708** metadata associated with the pattern string. 4709** Then as long as the pattern string remains the same, 4710** the compiled regular expression can be reused on multiple 4711** invocations of the same function. 4712** 4713** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4714** associated by the sqlite3_set_auxdata() function with the Nth argument 4715** value to the application-defined function. ^If there is no metadata 4716** associated with the function argument, this sqlite3_get_auxdata() interface 4717** returns a NULL pointer. 4718** 4719** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4720** argument of the application-defined function. ^Subsequent 4721** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4722** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4723** NULL if the metadata has been discarded. 4724** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4725** SQLite will invoke the destructor function X with parameter P exactly 4726** once, when the metadata is discarded. 4727** SQLite is free to discard the metadata at any time, including: <ul> 4728** <li> ^(when the corresponding function parameter changes)^, or 4729** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4730** SQL statement)^, or 4731** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4732** parameter)^, or 4733** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4734** allocation error occurs.)^ </ul> 4735** 4736** Note the last bullet in particular. The destructor X in 4737** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4738** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4739** should be called near the end of the function implementation and the 4740** function implementation should not make any use of P after 4741** sqlite3_set_auxdata() has been called. 4742** 4743** ^(In practice, metadata is preserved between function calls for 4744** function parameters that are compile-time constants, including literal 4745** values and [parameters] and expressions composed from the same.)^ 4746** 4747** These routines must be called from the same thread in which 4748** the SQL function is running. 4749*/ 4750void *sqlite3_get_auxdata(sqlite3_context*, int N); 4751void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4752 4753 4754/* 4755** CAPI3REF: Constants Defining Special Destructor Behavior 4756** 4757** These are special values for the destructor that is passed in as the 4758** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4759** argument is SQLITE_STATIC, it means that the content pointer is constant 4760** and will never change. It does not need to be destroyed. ^The 4761** SQLITE_TRANSIENT value means that the content will likely change in 4762** the near future and that SQLite should make its own private copy of 4763** the content before returning. 4764** 4765** The typedef is necessary to work around problems in certain 4766** C++ compilers. 4767*/ 4768typedef void (*sqlite3_destructor_type)(void*); 4769#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4770#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4771 4772/* 4773** CAPI3REF: Setting The Result Of An SQL Function 4774** METHOD: sqlite3_context 4775** 4776** These routines are used by the xFunc or xFinal callbacks that 4777** implement SQL functions and aggregates. See 4778** [sqlite3_create_function()] and [sqlite3_create_function16()] 4779** for additional information. 4780** 4781** These functions work very much like the [parameter binding] family of 4782** functions used to bind values to host parameters in prepared statements. 4783** Refer to the [SQL parameter] documentation for additional information. 4784** 4785** ^The sqlite3_result_blob() interface sets the result from 4786** an application-defined function to be the BLOB whose content is pointed 4787** to by the second parameter and which is N bytes long where N is the 4788** third parameter. 4789** 4790** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 4791** interfaces set the result of the application-defined function to be 4792** a BLOB containing all zero bytes and N bytes in size. 4793** 4794** ^The sqlite3_result_double() interface sets the result from 4795** an application-defined function to be a floating point value specified 4796** by its 2nd argument. 4797** 4798** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4799** cause the implemented SQL function to throw an exception. 4800** ^SQLite uses the string pointed to by the 4801** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4802** as the text of an error message. ^SQLite interprets the error 4803** message string from sqlite3_result_error() as UTF-8. ^SQLite 4804** interprets the string from sqlite3_result_error16() as UTF-16 in native 4805** byte order. ^If the third parameter to sqlite3_result_error() 4806** or sqlite3_result_error16() is negative then SQLite takes as the error 4807** message all text up through the first zero character. 4808** ^If the third parameter to sqlite3_result_error() or 4809** sqlite3_result_error16() is non-negative then SQLite takes that many 4810** bytes (not characters) from the 2nd parameter as the error message. 4811** ^The sqlite3_result_error() and sqlite3_result_error16() 4812** routines make a private copy of the error message text before 4813** they return. Hence, the calling function can deallocate or 4814** modify the text after they return without harm. 4815** ^The sqlite3_result_error_code() function changes the error code 4816** returned by SQLite as a result of an error in a function. ^By default, 4817** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4818** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4819** 4820** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 4821** error indicating that a string or BLOB is too long to represent. 4822** 4823** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 4824** error indicating that a memory allocation failed. 4825** 4826** ^The sqlite3_result_int() interface sets the return value 4827** of the application-defined function to be the 32-bit signed integer 4828** value given in the 2nd argument. 4829** ^The sqlite3_result_int64() interface sets the return value 4830** of the application-defined function to be the 64-bit signed integer 4831** value given in the 2nd argument. 4832** 4833** ^The sqlite3_result_null() interface sets the return value 4834** of the application-defined function to be NULL. 4835** 4836** ^The sqlite3_result_text(), sqlite3_result_text16(), 4837** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4838** set the return value of the application-defined function to be 4839** a text string which is represented as UTF-8, UTF-16 native byte order, 4840** UTF-16 little endian, or UTF-16 big endian, respectively. 4841** ^The sqlite3_result_text64() interface sets the return value of an 4842** application-defined function to be a text string in an encoding 4843** specified by the fifth (and last) parameter, which must be one 4844** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 4845** ^SQLite takes the text result from the application from 4846** the 2nd parameter of the sqlite3_result_text* interfaces. 4847** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4848** is negative, then SQLite takes result text from the 2nd parameter 4849** through the first zero character. 4850** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4851** is non-negative, then as many bytes (not characters) of the text 4852** pointed to by the 2nd parameter are taken as the application-defined 4853** function result. If the 3rd parameter is non-negative, then it 4854** must be the byte offset into the string where the NUL terminator would 4855** appear if the string where NUL terminated. If any NUL characters occur 4856** in the string at a byte offset that is less than the value of the 3rd 4857** parameter, then the resulting string will contain embedded NULs and the 4858** result of expressions operating on strings with embedded NULs is undefined. 4859** ^If the 4th parameter to the sqlite3_result_text* interfaces 4860** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4861** function as the destructor on the text or BLOB result when it has 4862** finished using that result. 4863** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4864** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4865** assumes that the text or BLOB result is in constant space and does not 4866** copy the content of the parameter nor call a destructor on the content 4867** when it has finished using that result. 4868** ^If the 4th parameter to the sqlite3_result_text* interfaces 4869** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4870** then SQLite makes a copy of the result into space obtained from 4871** from [sqlite3_malloc()] before it returns. 4872** 4873** ^The sqlite3_result_value() interface sets the result of 4874** the application-defined function to be a copy of the 4875** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4876** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4877** so that the [sqlite3_value] specified in the parameter may change or 4878** be deallocated after sqlite3_result_value() returns without harm. 4879** ^A [protected sqlite3_value] object may always be used where an 4880** [unprotected sqlite3_value] object is required, so either 4881** kind of [sqlite3_value] object can be used with this interface. 4882** 4883** If these routines are called from within the different thread 4884** than the one containing the application-defined function that received 4885** the [sqlite3_context] pointer, the results are undefined. 4886*/ 4887void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4888void sqlite3_result_blob64(sqlite3_context*,const void*, 4889 sqlite3_uint64,void(*)(void*)); 4890void sqlite3_result_double(sqlite3_context*, double); 4891void sqlite3_result_error(sqlite3_context*, const char*, int); 4892void sqlite3_result_error16(sqlite3_context*, const void*, int); 4893void sqlite3_result_error_toobig(sqlite3_context*); 4894void sqlite3_result_error_nomem(sqlite3_context*); 4895void sqlite3_result_error_code(sqlite3_context*, int); 4896void sqlite3_result_int(sqlite3_context*, int); 4897void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4898void sqlite3_result_null(sqlite3_context*); 4899void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4900void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 4901 void(*)(void*), unsigned char encoding); 4902void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4903void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4904void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4905void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4906void sqlite3_result_zeroblob(sqlite3_context*, int n); 4907int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 4908 4909 4910/* 4911** CAPI3REF: Setting The Subtype Of An SQL Function 4912** METHOD: sqlite3_context 4913** 4914** The sqlite3_result_subtype(C,T) function causes the subtype of 4915** the result from the [application-defined SQL function] with 4916** [sqlite3_context] C to be the value T. Only the lower 8 bits 4917** of the subtype T are preserved in current versions of SQLite; 4918** higher order bits are discarded. 4919** The number of subtype bytes preserved by SQLite might increase 4920** in future releases of SQLite. 4921*/ 4922void sqlite3_result_subtype(sqlite3_context*,unsigned int); 4923 4924/* 4925** CAPI3REF: Define New Collating Sequences 4926** METHOD: sqlite3 4927** 4928** ^These functions add, remove, or modify a [collation] associated 4929** with the [database connection] specified as the first argument. 4930** 4931** ^The name of the collation is a UTF-8 string 4932** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4933** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4934** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4935** considered to be the same name. 4936** 4937** ^(The third argument (eTextRep) must be one of the constants: 4938** <ul> 4939** <li> [SQLITE_UTF8], 4940** <li> [SQLITE_UTF16LE], 4941** <li> [SQLITE_UTF16BE], 4942** <li> [SQLITE_UTF16], or 4943** <li> [SQLITE_UTF16_ALIGNED]. 4944** </ul>)^ 4945** ^The eTextRep argument determines the encoding of strings passed 4946** to the collating function callback, xCallback. 4947** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4948** force strings to be UTF16 with native byte order. 4949** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4950** on an even byte address. 4951** 4952** ^The fourth argument, pArg, is an application data pointer that is passed 4953** through as the first argument to the collating function callback. 4954** 4955** ^The fifth argument, xCallback, is a pointer to the collating function. 4956** ^Multiple collating functions can be registered using the same name but 4957** with different eTextRep parameters and SQLite will use whichever 4958** function requires the least amount of data transformation. 4959** ^If the xCallback argument is NULL then the collating function is 4960** deleted. ^When all collating functions having the same name are deleted, 4961** that collation is no longer usable. 4962** 4963** ^The collating function callback is invoked with a copy of the pArg 4964** application data pointer and with two strings in the encoding specified 4965** by the eTextRep argument. The collating function must return an 4966** integer that is negative, zero, or positive 4967** if the first string is less than, equal to, or greater than the second, 4968** respectively. A collating function must always return the same answer 4969** given the same inputs. If two or more collating functions are registered 4970** to the same collation name (using different eTextRep values) then all 4971** must give an equivalent answer when invoked with equivalent strings. 4972** The collating function must obey the following properties for all 4973** strings A, B, and C: 4974** 4975** <ol> 4976** <li> If A==B then B==A. 4977** <li> If A==B and B==C then A==C. 4978** <li> If A<B THEN B>A. 4979** <li> If A<B and B<C then A<C. 4980** </ol> 4981** 4982** If a collating function fails any of the above constraints and that 4983** collating function is registered and used, then the behavior of SQLite 4984** is undefined. 4985** 4986** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4987** with the addition that the xDestroy callback is invoked on pArg when 4988** the collating function is deleted. 4989** ^Collating functions are deleted when they are overridden by later 4990** calls to the collation creation functions or when the 4991** [database connection] is closed using [sqlite3_close()]. 4992** 4993** ^The xDestroy callback is <u>not</u> called if the 4994** sqlite3_create_collation_v2() function fails. Applications that invoke 4995** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4996** check the return code and dispose of the application data pointer 4997** themselves rather than expecting SQLite to deal with it for them. 4998** This is different from every other SQLite interface. The inconsistency 4999** is unfortunate but cannot be changed without breaking backwards 5000** compatibility. 5001** 5002** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5003*/ 5004int sqlite3_create_collation( 5005 sqlite3*, 5006 const char *zName, 5007 int eTextRep, 5008 void *pArg, 5009 int(*xCompare)(void*,int,const void*,int,const void*) 5010); 5011int sqlite3_create_collation_v2( 5012 sqlite3*, 5013 const char *zName, 5014 int eTextRep, 5015 void *pArg, 5016 int(*xCompare)(void*,int,const void*,int,const void*), 5017 void(*xDestroy)(void*) 5018); 5019int sqlite3_create_collation16( 5020 sqlite3*, 5021 const void *zName, 5022 int eTextRep, 5023 void *pArg, 5024 int(*xCompare)(void*,int,const void*,int,const void*) 5025); 5026 5027/* 5028** CAPI3REF: Collation Needed Callbacks 5029** METHOD: sqlite3 5030** 5031** ^To avoid having to register all collation sequences before a database 5032** can be used, a single callback function may be registered with the 5033** [database connection] to be invoked whenever an undefined collation 5034** sequence is required. 5035** 5036** ^If the function is registered using the sqlite3_collation_needed() API, 5037** then it is passed the names of undefined collation sequences as strings 5038** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5039** the names are passed as UTF-16 in machine native byte order. 5040** ^A call to either function replaces the existing collation-needed callback. 5041** 5042** ^(When the callback is invoked, the first argument passed is a copy 5043** of the second argument to sqlite3_collation_needed() or 5044** sqlite3_collation_needed16(). The second argument is the database 5045** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5046** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5047** sequence function required. The fourth parameter is the name of the 5048** required collation sequence.)^ 5049** 5050** The callback function should register the desired collation using 5051** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5052** [sqlite3_create_collation_v2()]. 5053*/ 5054int sqlite3_collation_needed( 5055 sqlite3*, 5056 void*, 5057 void(*)(void*,sqlite3*,int eTextRep,const char*) 5058); 5059int sqlite3_collation_needed16( 5060 sqlite3*, 5061 void*, 5062 void(*)(void*,sqlite3*,int eTextRep,const void*) 5063); 5064 5065#ifdef SQLITE_HAS_CODEC 5066/* 5067** Specify the key for an encrypted database. This routine should be 5068** called right after sqlite3_open(). 5069** 5070** The code to implement this API is not available in the public release 5071** of SQLite. 5072*/ 5073int sqlite3_key( 5074 sqlite3 *db, /* Database to be rekeyed */ 5075 const void *pKey, int nKey /* The key */ 5076); 5077int sqlite3_key_v2( 5078 sqlite3 *db, /* Database to be rekeyed */ 5079 const char *zDbName, /* Name of the database */ 5080 const void *pKey, int nKey /* The key */ 5081); 5082 5083/* 5084** Change the key on an open database. If the current database is not 5085** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5086** database is decrypted. 5087** 5088** The code to implement this API is not available in the public release 5089** of SQLite. 5090*/ 5091int sqlite3_rekey( 5092 sqlite3 *db, /* Database to be rekeyed */ 5093 const void *pKey, int nKey /* The new key */ 5094); 5095int sqlite3_rekey_v2( 5096 sqlite3 *db, /* Database to be rekeyed */ 5097 const char *zDbName, /* Name of the database */ 5098 const void *pKey, int nKey /* The new key */ 5099); 5100 5101/* 5102** Specify the activation key for a SEE database. Unless 5103** activated, none of the SEE routines will work. 5104*/ 5105void sqlite3_activate_see( 5106 const char *zPassPhrase /* Activation phrase */ 5107); 5108#endif 5109 5110#ifdef SQLITE_ENABLE_CEROD 5111/* 5112** Specify the activation key for a CEROD database. Unless 5113** activated, none of the CEROD routines will work. 5114*/ 5115void sqlite3_activate_cerod( 5116 const char *zPassPhrase /* Activation phrase */ 5117); 5118#endif 5119 5120/* 5121** CAPI3REF: Suspend Execution For A Short Time 5122** 5123** The sqlite3_sleep() function causes the current thread to suspend execution 5124** for at least a number of milliseconds specified in its parameter. 5125** 5126** If the operating system does not support sleep requests with 5127** millisecond time resolution, then the time will be rounded up to 5128** the nearest second. The number of milliseconds of sleep actually 5129** requested from the operating system is returned. 5130** 5131** ^SQLite implements this interface by calling the xSleep() 5132** method of the default [sqlite3_vfs] object. If the xSleep() method 5133** of the default VFS is not implemented correctly, or not implemented at 5134** all, then the behavior of sqlite3_sleep() may deviate from the description 5135** in the previous paragraphs. 5136*/ 5137int sqlite3_sleep(int); 5138 5139/* 5140** CAPI3REF: Name Of The Folder Holding Temporary Files 5141** 5142** ^(If this global variable is made to point to a string which is 5143** the name of a folder (a.k.a. directory), then all temporary files 5144** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5145** will be placed in that directory.)^ ^If this variable 5146** is a NULL pointer, then SQLite performs a search for an appropriate 5147** temporary file directory. 5148** 5149** Applications are strongly discouraged from using this global variable. 5150** It is required to set a temporary folder on Windows Runtime (WinRT). 5151** But for all other platforms, it is highly recommended that applications 5152** neither read nor write this variable. This global variable is a relic 5153** that exists for backwards compatibility of legacy applications and should 5154** be avoided in new projects. 5155** 5156** It is not safe to read or modify this variable in more than one 5157** thread at a time. It is not safe to read or modify this variable 5158** if a [database connection] is being used at the same time in a separate 5159** thread. 5160** It is intended that this variable be set once 5161** as part of process initialization and before any SQLite interface 5162** routines have been called and that this variable remain unchanged 5163** thereafter. 5164** 5165** ^The [temp_store_directory pragma] may modify this variable and cause 5166** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5167** the [temp_store_directory pragma] always assumes that any string 5168** that this variable points to is held in memory obtained from 5169** [sqlite3_malloc] and the pragma may attempt to free that memory 5170** using [sqlite3_free]. 5171** Hence, if this variable is modified directly, either it should be 5172** made NULL or made to point to memory obtained from [sqlite3_malloc] 5173** or else the use of the [temp_store_directory pragma] should be avoided. 5174** Except when requested by the [temp_store_directory pragma], SQLite 5175** does not free the memory that sqlite3_temp_directory points to. If 5176** the application wants that memory to be freed, it must do 5177** so itself, taking care to only do so after all [database connection] 5178** objects have been destroyed. 5179** 5180** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5181** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5182** features that require the use of temporary files may fail. Here is an 5183** example of how to do this using C++ with the Windows Runtime: 5184** 5185** <blockquote><pre> 5186** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5187** TemporaryFolder->Path->Data(); 5188** char zPathBuf[MAX_PATH + 1]; 5189** memset(zPathBuf, 0, sizeof(zPathBuf)); 5190** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5191** NULL, NULL); 5192** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5193** </pre></blockquote> 5194*/ 5195SQLITE_EXTERN char *sqlite3_temp_directory; 5196 5197/* 5198** CAPI3REF: Name Of The Folder Holding Database Files 5199** 5200** ^(If this global variable is made to point to a string which is 5201** the name of a folder (a.k.a. directory), then all database files 5202** specified with a relative pathname and created or accessed by 5203** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5204** to be relative to that directory.)^ ^If this variable is a NULL 5205** pointer, then SQLite assumes that all database files specified 5206** with a relative pathname are relative to the current directory 5207** for the process. Only the windows VFS makes use of this global 5208** variable; it is ignored by the unix VFS. 5209** 5210** Changing the value of this variable while a database connection is 5211** open can result in a corrupt database. 5212** 5213** It is not safe to read or modify this variable in more than one 5214** thread at a time. It is not safe to read or modify this variable 5215** if a [database connection] is being used at the same time in a separate 5216** thread. 5217** It is intended that this variable be set once 5218** as part of process initialization and before any SQLite interface 5219** routines have been called and that this variable remain unchanged 5220** thereafter. 5221** 5222** ^The [data_store_directory pragma] may modify this variable and cause 5223** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5224** the [data_store_directory pragma] always assumes that any string 5225** that this variable points to is held in memory obtained from 5226** [sqlite3_malloc] and the pragma may attempt to free that memory 5227** using [sqlite3_free]. 5228** Hence, if this variable is modified directly, either it should be 5229** made NULL or made to point to memory obtained from [sqlite3_malloc] 5230** or else the use of the [data_store_directory pragma] should be avoided. 5231*/ 5232SQLITE_EXTERN char *sqlite3_data_directory; 5233 5234/* 5235** CAPI3REF: Test For Auto-Commit Mode 5236** KEYWORDS: {autocommit mode} 5237** METHOD: sqlite3 5238** 5239** ^The sqlite3_get_autocommit() interface returns non-zero or 5240** zero if the given database connection is or is not in autocommit mode, 5241** respectively. ^Autocommit mode is on by default. 5242** ^Autocommit mode is disabled by a [BEGIN] statement. 5243** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5244** 5245** If certain kinds of errors occur on a statement within a multi-statement 5246** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5247** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5248** transaction might be rolled back automatically. The only way to 5249** find out whether SQLite automatically rolled back the transaction after 5250** an error is to use this function. 5251** 5252** If another thread changes the autocommit status of the database 5253** connection while this routine is running, then the return value 5254** is undefined. 5255*/ 5256int sqlite3_get_autocommit(sqlite3*); 5257 5258/* 5259** CAPI3REF: Find The Database Handle Of A Prepared Statement 5260** METHOD: sqlite3_stmt 5261** 5262** ^The sqlite3_db_handle interface returns the [database connection] handle 5263** to which a [prepared statement] belongs. ^The [database connection] 5264** returned by sqlite3_db_handle is the same [database connection] 5265** that was the first argument 5266** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5267** create the statement in the first place. 5268*/ 5269sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5270 5271/* 5272** CAPI3REF: Return The Filename For A Database Connection 5273** METHOD: sqlite3 5274** 5275** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5276** associated with database N of connection D. ^The main database file 5277** has the name "main". If there is no attached database N on the database 5278** connection D, or if database N is a temporary or in-memory database, then 5279** a NULL pointer is returned. 5280** 5281** ^The filename returned by this function is the output of the 5282** xFullPathname method of the [VFS]. ^In other words, the filename 5283** will be an absolute pathname, even if the filename used 5284** to open the database originally was a URI or relative pathname. 5285*/ 5286const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5287 5288/* 5289** CAPI3REF: Determine if a database is read-only 5290** METHOD: sqlite3 5291** 5292** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5293** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5294** the name of a database on connection D. 5295*/ 5296int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5297 5298/* 5299** CAPI3REF: Find the next prepared statement 5300** METHOD: sqlite3 5301** 5302** ^This interface returns a pointer to the next [prepared statement] after 5303** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5304** then this interface returns a pointer to the first prepared statement 5305** associated with the database connection pDb. ^If no prepared statement 5306** satisfies the conditions of this routine, it returns NULL. 5307** 5308** The [database connection] pointer D in a call to 5309** [sqlite3_next_stmt(D,S)] must refer to an open database 5310** connection and in particular must not be a NULL pointer. 5311*/ 5312sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5313 5314/* 5315** CAPI3REF: Commit And Rollback Notification Callbacks 5316** METHOD: sqlite3 5317** 5318** ^The sqlite3_commit_hook() interface registers a callback 5319** function to be invoked whenever a transaction is [COMMIT | committed]. 5320** ^Any callback set by a previous call to sqlite3_commit_hook() 5321** for the same database connection is overridden. 5322** ^The sqlite3_rollback_hook() interface registers a callback 5323** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5324** ^Any callback set by a previous call to sqlite3_rollback_hook() 5325** for the same database connection is overridden. 5326** ^The pArg argument is passed through to the callback. 5327** ^If the callback on a commit hook function returns non-zero, 5328** then the commit is converted into a rollback. 5329** 5330** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5331** return the P argument from the previous call of the same function 5332** on the same [database connection] D, or NULL for 5333** the first call for each function on D. 5334** 5335** The commit and rollback hook callbacks are not reentrant. 5336** The callback implementation must not do anything that will modify 5337** the database connection that invoked the callback. Any actions 5338** to modify the database connection must be deferred until after the 5339** completion of the [sqlite3_step()] call that triggered the commit 5340** or rollback hook in the first place. 5341** Note that running any other SQL statements, including SELECT statements, 5342** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5343** the database connections for the meaning of "modify" in this paragraph. 5344** 5345** ^Registering a NULL function disables the callback. 5346** 5347** ^When the commit hook callback routine returns zero, the [COMMIT] 5348** operation is allowed to continue normally. ^If the commit hook 5349** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5350** ^The rollback hook is invoked on a rollback that results from a commit 5351** hook returning non-zero, just as it would be with any other rollback. 5352** 5353** ^For the purposes of this API, a transaction is said to have been 5354** rolled back if an explicit "ROLLBACK" statement is executed, or 5355** an error or constraint causes an implicit rollback to occur. 5356** ^The rollback callback is not invoked if a transaction is 5357** automatically rolled back because the database connection is closed. 5358** 5359** See also the [sqlite3_update_hook()] interface. 5360*/ 5361void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5362void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5363 5364/* 5365** CAPI3REF: Data Change Notification Callbacks 5366** METHOD: sqlite3 5367** 5368** ^The sqlite3_update_hook() interface registers a callback function 5369** with the [database connection] identified by the first argument 5370** to be invoked whenever a row is updated, inserted or deleted in 5371** a [rowid table]. 5372** ^Any callback set by a previous call to this function 5373** for the same database connection is overridden. 5374** 5375** ^The second argument is a pointer to the function to invoke when a 5376** row is updated, inserted or deleted in a rowid table. 5377** ^The first argument to the callback is a copy of the third argument 5378** to sqlite3_update_hook(). 5379** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5380** or [SQLITE_UPDATE], depending on the operation that caused the callback 5381** to be invoked. 5382** ^The third and fourth arguments to the callback contain pointers to the 5383** database and table name containing the affected row. 5384** ^The final callback parameter is the [rowid] of the row. 5385** ^In the case of an update, this is the [rowid] after the update takes place. 5386** 5387** ^(The update hook is not invoked when internal system tables are 5388** modified (i.e. sqlite_master and sqlite_sequence).)^ 5389** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5390** 5391** ^In the current implementation, the update hook 5392** is not invoked when duplication rows are deleted because of an 5393** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5394** invoked when rows are deleted using the [truncate optimization]. 5395** The exceptions defined in this paragraph might change in a future 5396** release of SQLite. 5397** 5398** The update hook implementation must not do anything that will modify 5399** the database connection that invoked the update hook. Any actions 5400** to modify the database connection must be deferred until after the 5401** completion of the [sqlite3_step()] call that triggered the update hook. 5402** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5403** database connections for the meaning of "modify" in this paragraph. 5404** 5405** ^The sqlite3_update_hook(D,C,P) function 5406** returns the P argument from the previous call 5407** on the same [database connection] D, or NULL for 5408** the first call on D. 5409** 5410** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5411** and [sqlite3_preupdate_hook()] interfaces. 5412*/ 5413void *sqlite3_update_hook( 5414 sqlite3*, 5415 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5416 void* 5417); 5418 5419/* 5420** CAPI3REF: Enable Or Disable Shared Pager Cache 5421** 5422** ^(This routine enables or disables the sharing of the database cache 5423** and schema data structures between [database connection | connections] 5424** to the same database. Sharing is enabled if the argument is true 5425** and disabled if the argument is false.)^ 5426** 5427** ^Cache sharing is enabled and disabled for an entire process. 5428** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5429** In prior versions of SQLite, 5430** sharing was enabled or disabled for each thread separately. 5431** 5432** ^(The cache sharing mode set by this interface effects all subsequent 5433** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5434** Existing database connections continue use the sharing mode 5435** that was in effect at the time they were opened.)^ 5436** 5437** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5438** successfully. An [error code] is returned otherwise.)^ 5439** 5440** ^Shared cache is disabled by default. But this might change in 5441** future releases of SQLite. Applications that care about shared 5442** cache setting should set it explicitly. 5443** 5444** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5445** and will always return SQLITE_MISUSE. On those systems, 5446** shared cache mode should be enabled per-database connection via 5447** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5448** 5449** This interface is threadsafe on processors where writing a 5450** 32-bit integer is atomic. 5451** 5452** See Also: [SQLite Shared-Cache Mode] 5453*/ 5454int sqlite3_enable_shared_cache(int); 5455 5456/* 5457** CAPI3REF: Attempt To Free Heap Memory 5458** 5459** ^The sqlite3_release_memory() interface attempts to free N bytes 5460** of heap memory by deallocating non-essential memory allocations 5461** held by the database library. Memory used to cache database 5462** pages to improve performance is an example of non-essential memory. 5463** ^sqlite3_release_memory() returns the number of bytes actually freed, 5464** which might be more or less than the amount requested. 5465** ^The sqlite3_release_memory() routine is a no-op returning zero 5466** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5467** 5468** See also: [sqlite3_db_release_memory()] 5469*/ 5470int sqlite3_release_memory(int); 5471 5472/* 5473** CAPI3REF: Free Memory Used By A Database Connection 5474** METHOD: sqlite3 5475** 5476** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5477** memory as possible from database connection D. Unlike the 5478** [sqlite3_release_memory()] interface, this interface is in effect even 5479** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5480** omitted. 5481** 5482** See also: [sqlite3_release_memory()] 5483*/ 5484int sqlite3_db_release_memory(sqlite3*); 5485 5486/* 5487** CAPI3REF: Impose A Limit On Heap Size 5488** 5489** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5490** soft limit on the amount of heap memory that may be allocated by SQLite. 5491** ^SQLite strives to keep heap memory utilization below the soft heap 5492** limit by reducing the number of pages held in the page cache 5493** as heap memory usages approaches the limit. 5494** ^The soft heap limit is "soft" because even though SQLite strives to stay 5495** below the limit, it will exceed the limit rather than generate 5496** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5497** is advisory only. 5498** 5499** ^The return value from sqlite3_soft_heap_limit64() is the size of 5500** the soft heap limit prior to the call, or negative in the case of an 5501** error. ^If the argument N is negative 5502** then no change is made to the soft heap limit. Hence, the current 5503** size of the soft heap limit can be determined by invoking 5504** sqlite3_soft_heap_limit64() with a negative argument. 5505** 5506** ^If the argument N is zero then the soft heap limit is disabled. 5507** 5508** ^(The soft heap limit is not enforced in the current implementation 5509** if one or more of following conditions are true: 5510** 5511** <ul> 5512** <li> The soft heap limit is set to zero. 5513** <li> Memory accounting is disabled using a combination of the 5514** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5515** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5516** <li> An alternative page cache implementation is specified using 5517** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5518** <li> The page cache allocates from its own memory pool supplied 5519** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5520** from the heap. 5521** </ul>)^ 5522** 5523** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5524** the soft heap limit is enforced 5525** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5526** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5527** the soft heap limit is enforced on every memory allocation. Without 5528** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5529** when memory is allocated by the page cache. Testing suggests that because 5530** the page cache is the predominate memory user in SQLite, most 5531** applications will achieve adequate soft heap limit enforcement without 5532** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5533** 5534** The circumstances under which SQLite will enforce the soft heap limit may 5535** changes in future releases of SQLite. 5536*/ 5537sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5538 5539/* 5540** CAPI3REF: Deprecated Soft Heap Limit Interface 5541** DEPRECATED 5542** 5543** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5544** interface. This routine is provided for historical compatibility 5545** only. All new applications should use the 5546** [sqlite3_soft_heap_limit64()] interface rather than this one. 5547*/ 5548SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5549 5550 5551/* 5552** CAPI3REF: Extract Metadata About A Column Of A Table 5553** METHOD: sqlite3 5554** 5555** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5556** information about column C of table T in database D 5557** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5558** interface returns SQLITE_OK and fills in the non-NULL pointers in 5559** the final five arguments with appropriate values if the specified 5560** column exists. ^The sqlite3_table_column_metadata() interface returns 5561** SQLITE_ERROR and if the specified column does not exist. 5562** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5563** NULL pointer, then this routine simply checks for the existence of the 5564** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5565** does not. 5566** 5567** ^The column is identified by the second, third and fourth parameters to 5568** this function. ^(The second parameter is either the name of the database 5569** (i.e. "main", "temp", or an attached database) containing the specified 5570** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5571** for the table using the same algorithm used by the database engine to 5572** resolve unqualified table references. 5573** 5574** ^The third and fourth parameters to this function are the table and column 5575** name of the desired column, respectively. 5576** 5577** ^Metadata is returned by writing to the memory locations passed as the 5th 5578** and subsequent parameters to this function. ^Any of these arguments may be 5579** NULL, in which case the corresponding element of metadata is omitted. 5580** 5581** ^(<blockquote> 5582** <table border="1"> 5583** <tr><th> Parameter <th> Output<br>Type <th> Description 5584** 5585** <tr><td> 5th <td> const char* <td> Data type 5586** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5587** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5588** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5589** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5590** </table> 5591** </blockquote>)^ 5592** 5593** ^The memory pointed to by the character pointers returned for the 5594** declaration type and collation sequence is valid until the next 5595** call to any SQLite API function. 5596** 5597** ^If the specified table is actually a view, an [error code] is returned. 5598** 5599** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5600** is not a [WITHOUT ROWID] table and an 5601** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5602** parameters are set for the explicitly declared column. ^(If there is no 5603** [INTEGER PRIMARY KEY] column, then the outputs 5604** for the [rowid] are set as follows: 5605** 5606** <pre> 5607** data type: "INTEGER" 5608** collation sequence: "BINARY" 5609** not null: 0 5610** primary key: 1 5611** auto increment: 0 5612** </pre>)^ 5613** 5614** ^This function causes all database schemas to be read from disk and 5615** parsed, if that has not already been done, and returns an error if 5616** any errors are encountered while loading the schema. 5617*/ 5618int sqlite3_table_column_metadata( 5619 sqlite3 *db, /* Connection handle */ 5620 const char *zDbName, /* Database name or NULL */ 5621 const char *zTableName, /* Table name */ 5622 const char *zColumnName, /* Column name */ 5623 char const **pzDataType, /* OUTPUT: Declared data type */ 5624 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5625 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5626 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5627 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5628); 5629 5630/* 5631** CAPI3REF: Load An Extension 5632** METHOD: sqlite3 5633** 5634** ^This interface loads an SQLite extension library from the named file. 5635** 5636** ^The sqlite3_load_extension() interface attempts to load an 5637** [SQLite extension] library contained in the file zFile. If 5638** the file cannot be loaded directly, attempts are made to load 5639** with various operating-system specific extensions added. 5640** So for example, if "samplelib" cannot be loaded, then names like 5641** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5642** be tried also. 5643** 5644** ^The entry point is zProc. 5645** ^(zProc may be 0, in which case SQLite will try to come up with an 5646** entry point name on its own. It first tries "sqlite3_extension_init". 5647** If that does not work, it constructs a name "sqlite3_X_init" where the 5648** X is consists of the lower-case equivalent of all ASCII alphabetic 5649** characters in the filename from the last "/" to the first following 5650** "." and omitting any initial "lib".)^ 5651** ^The sqlite3_load_extension() interface returns 5652** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5653** ^If an error occurs and pzErrMsg is not 0, then the 5654** [sqlite3_load_extension()] interface shall attempt to 5655** fill *pzErrMsg with error message text stored in memory 5656** obtained from [sqlite3_malloc()]. The calling function 5657** should free this memory by calling [sqlite3_free()]. 5658** 5659** ^Extension loading must be enabled using 5660** [sqlite3_enable_load_extension()] or 5661** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5662** prior to calling this API, 5663** otherwise an error will be returned. 5664** 5665** <b>Security warning:</b> It is recommended that the 5666** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5667** interface. The use of the [sqlite3_enable_load_extension()] interface 5668** should be avoided. This will keep the SQL function [load_extension()] 5669** disabled and prevent SQL injections from giving attackers 5670** access to extension loading capabilities. 5671** 5672** See also the [load_extension() SQL function]. 5673*/ 5674int sqlite3_load_extension( 5675 sqlite3 *db, /* Load the extension into this database connection */ 5676 const char *zFile, /* Name of the shared library containing extension */ 5677 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5678 char **pzErrMsg /* Put error message here if not 0 */ 5679); 5680 5681/* 5682** CAPI3REF: Enable Or Disable Extension Loading 5683** METHOD: sqlite3 5684** 5685** ^So as not to open security holes in older applications that are 5686** unprepared to deal with [extension loading], and as a means of disabling 5687** [extension loading] while evaluating user-entered SQL, the following API 5688** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5689** 5690** ^Extension loading is off by default. 5691** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5692** to turn extension loading on and call it with onoff==0 to turn 5693** it back off again. 5694** 5695** ^This interface enables or disables both the C-API 5696** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5697** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5698** to enable or disable only the C-API.)^ 5699** 5700** <b>Security warning:</b> It is recommended that extension loading 5701** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5702** rather than this interface, so the [load_extension()] SQL function 5703** remains disabled. This will prevent SQL injections from giving attackers 5704** access to extension loading capabilities. 5705*/ 5706int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5707 5708/* 5709** CAPI3REF: Automatically Load Statically Linked Extensions 5710** 5711** ^This interface causes the xEntryPoint() function to be invoked for 5712** each new [database connection] that is created. The idea here is that 5713** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5714** that is to be automatically loaded into all new database connections. 5715** 5716** ^(Even though the function prototype shows that xEntryPoint() takes 5717** no arguments and returns void, SQLite invokes xEntryPoint() with three 5718** arguments and expects an integer result as if the signature of the 5719** entry point where as follows: 5720** 5721** <blockquote><pre> 5722** int xEntryPoint( 5723** sqlite3 *db, 5724** const char **pzErrMsg, 5725** const struct sqlite3_api_routines *pThunk 5726** ); 5727** </pre></blockquote>)^ 5728** 5729** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5730** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5731** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5732** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5733** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5734** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5735** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 5736** 5737** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 5738** on the list of automatic extensions is a harmless no-op. ^No entry point 5739** will be called more than once for each database connection that is opened. 5740** 5741** See also: [sqlite3_reset_auto_extension()] 5742** and [sqlite3_cancel_auto_extension()] 5743*/ 5744int sqlite3_auto_extension(void(*xEntryPoint)(void)); 5745 5746/* 5747** CAPI3REF: Cancel Automatic Extension Loading 5748** 5749** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 5750** initialization routine X that was registered using a prior call to 5751** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 5752** routine returns 1 if initialization routine X was successfully 5753** unregistered and it returns 0 if X was not on the list of initialization 5754** routines. 5755*/ 5756int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 5757 5758/* 5759** CAPI3REF: Reset Automatic Extension Loading 5760** 5761** ^This interface disables all automatic extensions previously 5762** registered using [sqlite3_auto_extension()]. 5763*/ 5764void sqlite3_reset_auto_extension(void); 5765 5766/* 5767** The interface to the virtual-table mechanism is currently considered 5768** to be experimental. The interface might change in incompatible ways. 5769** If this is a problem for you, do not use the interface at this time. 5770** 5771** When the virtual-table mechanism stabilizes, we will declare the 5772** interface fixed, support it indefinitely, and remove this comment. 5773*/ 5774 5775/* 5776** Structures used by the virtual table interface 5777*/ 5778typedef struct sqlite3_vtab sqlite3_vtab; 5779typedef struct sqlite3_index_info sqlite3_index_info; 5780typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 5781typedef struct sqlite3_module sqlite3_module; 5782 5783/* 5784** CAPI3REF: Virtual Table Object 5785** KEYWORDS: sqlite3_module {virtual table module} 5786** 5787** This structure, sometimes called a "virtual table module", 5788** defines the implementation of a [virtual tables]. 5789** This structure consists mostly of methods for the module. 5790** 5791** ^A virtual table module is created by filling in a persistent 5792** instance of this structure and passing a pointer to that instance 5793** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 5794** ^The registration remains valid until it is replaced by a different 5795** module or until the [database connection] closes. The content 5796** of this structure must not change while it is registered with 5797** any database connection. 5798*/ 5799struct sqlite3_module { 5800 int iVersion; 5801 int (*xCreate)(sqlite3*, void *pAux, 5802 int argc, const char *const*argv, 5803 sqlite3_vtab **ppVTab, char**); 5804 int (*xConnect)(sqlite3*, void *pAux, 5805 int argc, const char *const*argv, 5806 sqlite3_vtab **ppVTab, char**); 5807 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 5808 int (*xDisconnect)(sqlite3_vtab *pVTab); 5809 int (*xDestroy)(sqlite3_vtab *pVTab); 5810 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 5811 int (*xClose)(sqlite3_vtab_cursor*); 5812 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 5813 int argc, sqlite3_value **argv); 5814 int (*xNext)(sqlite3_vtab_cursor*); 5815 int (*xEof)(sqlite3_vtab_cursor*); 5816 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 5817 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 5818 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 5819 int (*xBegin)(sqlite3_vtab *pVTab); 5820 int (*xSync)(sqlite3_vtab *pVTab); 5821 int (*xCommit)(sqlite3_vtab *pVTab); 5822 int (*xRollback)(sqlite3_vtab *pVTab); 5823 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 5824 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 5825 void **ppArg); 5826 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 5827 /* The methods above are in version 1 of the sqlite_module object. Those 5828 ** below are for version 2 and greater. */ 5829 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 5830 int (*xRelease)(sqlite3_vtab *pVTab, int); 5831 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 5832}; 5833 5834/* 5835** CAPI3REF: Virtual Table Indexing Information 5836** KEYWORDS: sqlite3_index_info 5837** 5838** The sqlite3_index_info structure and its substructures is used as part 5839** of the [virtual table] interface to 5840** pass information into and receive the reply from the [xBestIndex] 5841** method of a [virtual table module]. The fields under **Inputs** are the 5842** inputs to xBestIndex and are read-only. xBestIndex inserts its 5843** results into the **Outputs** fields. 5844** 5845** ^(The aConstraint[] array records WHERE clause constraints of the form: 5846** 5847** <blockquote>column OP expr</blockquote> 5848** 5849** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 5850** stored in aConstraint[].op using one of the 5851** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5852** ^(The index of the column is stored in 5853** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5854** expr on the right-hand side can be evaluated (and thus the constraint 5855** is usable) and false if it cannot.)^ 5856** 5857** ^The optimizer automatically inverts terms of the form "expr OP column" 5858** and makes other simplifications to the WHERE clause in an attempt to 5859** get as many WHERE clause terms into the form shown above as possible. 5860** ^The aConstraint[] array only reports WHERE clause terms that are 5861** relevant to the particular virtual table being queried. 5862** 5863** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5864** ^Each term of aOrderBy records a column of the ORDER BY clause. 5865** 5866** The colUsed field indicates which columns of the virtual table may be 5867** required by the current scan. Virtual table columns are numbered from 5868** zero in the order in which they appear within the CREATE TABLE statement 5869** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 5870** the corresponding bit is set within the colUsed mask if the column may be 5871** required by SQLite. If the table has at least 64 columns and any column 5872** to the right of the first 63 is required, then bit 63 of colUsed is also 5873** set. In other words, column iCol may be required if the expression 5874** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 5875** non-zero. 5876** 5877** The [xBestIndex] method must fill aConstraintUsage[] with information 5878** about what parameters to pass to xFilter. ^If argvIndex>0 then 5879** the right-hand side of the corresponding aConstraint[] is evaluated 5880** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5881** is true, then the constraint is assumed to be fully handled by the 5882** virtual table and is not checked again by SQLite.)^ 5883** 5884** ^The idxNum and idxPtr values are recorded and passed into the 5885** [xFilter] method. 5886** ^[sqlite3_free()] is used to free idxPtr if and only if 5887** needToFreeIdxPtr is true. 5888** 5889** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5890** the correct order to satisfy the ORDER BY clause so that no separate 5891** sorting step is required. 5892** 5893** ^The estimatedCost value is an estimate of the cost of a particular 5894** strategy. A cost of N indicates that the cost of the strategy is similar 5895** to a linear scan of an SQLite table with N rows. A cost of log(N) 5896** indicates that the expense of the operation is similar to that of a 5897** binary search on a unique indexed field of an SQLite table with N rows. 5898** 5899** ^The estimatedRows value is an estimate of the number of rows that 5900** will be returned by the strategy. 5901** 5902** The xBestIndex method may optionally populate the idxFlags field with a 5903** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 5904** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 5905** assumes that the strategy may visit at most one row. 5906** 5907** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 5908** SQLite also assumes that if a call to the xUpdate() method is made as 5909** part of the same statement to delete or update a virtual table row and the 5910** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 5911** any database changes. In other words, if the xUpdate() returns 5912** SQLITE_CONSTRAINT, the database contents must be exactly as they were 5913** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 5914** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 5915** the xUpdate method are automatically rolled back by SQLite. 5916** 5917** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 5918** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 5919** If a virtual table extension is 5920** used with an SQLite version earlier than 3.8.2, the results of attempting 5921** to read or write the estimatedRows field are undefined (but are likely 5922** to included crashing the application). The estimatedRows field should 5923** therefore only be used if [sqlite3_libversion_number()] returns a 5924** value greater than or equal to 3008002. Similarly, the idxFlags field 5925** was added for [version 3.9.0] ([dateof:3.9.0]). 5926** It may therefore only be used if 5927** sqlite3_libversion_number() returns a value greater than or equal to 5928** 3009000. 5929*/ 5930struct sqlite3_index_info { 5931 /* Inputs */ 5932 int nConstraint; /* Number of entries in aConstraint */ 5933 struct sqlite3_index_constraint { 5934 int iColumn; /* Column constrained. -1 for ROWID */ 5935 unsigned char op; /* Constraint operator */ 5936 unsigned char usable; /* True if this constraint is usable */ 5937 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5938 } *aConstraint; /* Table of WHERE clause constraints */ 5939 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5940 struct sqlite3_index_orderby { 5941 int iColumn; /* Column number */ 5942 unsigned char desc; /* True for DESC. False for ASC. */ 5943 } *aOrderBy; /* The ORDER BY clause */ 5944 /* Outputs */ 5945 struct sqlite3_index_constraint_usage { 5946 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5947 unsigned char omit; /* Do not code a test for this constraint */ 5948 } *aConstraintUsage; 5949 int idxNum; /* Number used to identify the index */ 5950 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5951 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5952 int orderByConsumed; /* True if output is already ordered */ 5953 double estimatedCost; /* Estimated cost of using this index */ 5954 /* Fields below are only available in SQLite 3.8.2 and later */ 5955 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 5956 /* Fields below are only available in SQLite 3.9.0 and later */ 5957 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 5958 /* Fields below are only available in SQLite 3.10.0 and later */ 5959 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 5960}; 5961 5962/* 5963** CAPI3REF: Virtual Table Scan Flags 5964*/ 5965#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 5966 5967/* 5968** CAPI3REF: Virtual Table Constraint Operator Codes 5969** 5970** These macros defined the allowed values for the 5971** [sqlite3_index_info].aConstraint[].op field. Each value represents 5972** an operator that is part of a constraint term in the wHERE clause of 5973** a query that uses a [virtual table]. 5974*/ 5975#define SQLITE_INDEX_CONSTRAINT_EQ 2 5976#define SQLITE_INDEX_CONSTRAINT_GT 4 5977#define SQLITE_INDEX_CONSTRAINT_LE 8 5978#define SQLITE_INDEX_CONSTRAINT_LT 16 5979#define SQLITE_INDEX_CONSTRAINT_GE 32 5980#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5981#define SQLITE_INDEX_CONSTRAINT_LIKE 65 5982#define SQLITE_INDEX_CONSTRAINT_GLOB 66 5983#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 5984 5985/* 5986** CAPI3REF: Register A Virtual Table Implementation 5987** METHOD: sqlite3 5988** 5989** ^These routines are used to register a new [virtual table module] name. 5990** ^Module names must be registered before 5991** creating a new [virtual table] using the module and before using a 5992** preexisting [virtual table] for the module. 5993** 5994** ^The module name is registered on the [database connection] specified 5995** by the first parameter. ^The name of the module is given by the 5996** second parameter. ^The third parameter is a pointer to 5997** the implementation of the [virtual table module]. ^The fourth 5998** parameter is an arbitrary client data pointer that is passed through 5999** into the [xCreate] and [xConnect] methods of the virtual table module 6000** when a new virtual table is be being created or reinitialized. 6001** 6002** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6003** is a pointer to a destructor for the pClientData. ^SQLite will 6004** invoke the destructor function (if it is not NULL) when SQLite 6005** no longer needs the pClientData pointer. ^The destructor will also 6006** be invoked if the call to sqlite3_create_module_v2() fails. 6007** ^The sqlite3_create_module() 6008** interface is equivalent to sqlite3_create_module_v2() with a NULL 6009** destructor. 6010*/ 6011int sqlite3_create_module( 6012 sqlite3 *db, /* SQLite connection to register module with */ 6013 const char *zName, /* Name of the module */ 6014 const sqlite3_module *p, /* Methods for the module */ 6015 void *pClientData /* Client data for xCreate/xConnect */ 6016); 6017int sqlite3_create_module_v2( 6018 sqlite3 *db, /* SQLite connection to register module with */ 6019 const char *zName, /* Name of the module */ 6020 const sqlite3_module *p, /* Methods for the module */ 6021 void *pClientData, /* Client data for xCreate/xConnect */ 6022 void(*xDestroy)(void*) /* Module destructor function */ 6023); 6024 6025/* 6026** CAPI3REF: Virtual Table Instance Object 6027** KEYWORDS: sqlite3_vtab 6028** 6029** Every [virtual table module] implementation uses a subclass 6030** of this object to describe a particular instance 6031** of the [virtual table]. Each subclass will 6032** be tailored to the specific needs of the module implementation. 6033** The purpose of this superclass is to define certain fields that are 6034** common to all module implementations. 6035** 6036** ^Virtual tables methods can set an error message by assigning a 6037** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6038** take care that any prior string is freed by a call to [sqlite3_free()] 6039** prior to assigning a new string to zErrMsg. ^After the error message 6040** is delivered up to the client application, the string will be automatically 6041** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6042*/ 6043struct sqlite3_vtab { 6044 const sqlite3_module *pModule; /* The module for this virtual table */ 6045 int nRef; /* Number of open cursors */ 6046 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6047 /* Virtual table implementations will typically add additional fields */ 6048}; 6049 6050/* 6051** CAPI3REF: Virtual Table Cursor Object 6052** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6053** 6054** Every [virtual table module] implementation uses a subclass of the 6055** following structure to describe cursors that point into the 6056** [virtual table] and are used 6057** to loop through the virtual table. Cursors are created using the 6058** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6059** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6060** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6061** of the module. Each module implementation will define 6062** the content of a cursor structure to suit its own needs. 6063** 6064** This superclass exists in order to define fields of the cursor that 6065** are common to all implementations. 6066*/ 6067struct sqlite3_vtab_cursor { 6068 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6069 /* Virtual table implementations will typically add additional fields */ 6070}; 6071 6072/* 6073** CAPI3REF: Declare The Schema Of A Virtual Table 6074** 6075** ^The [xCreate] and [xConnect] methods of a 6076** [virtual table module] call this interface 6077** to declare the format (the names and datatypes of the columns) of 6078** the virtual tables they implement. 6079*/ 6080int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6081 6082/* 6083** CAPI3REF: Overload A Function For A Virtual Table 6084** METHOD: sqlite3 6085** 6086** ^(Virtual tables can provide alternative implementations of functions 6087** using the [xFindFunction] method of the [virtual table module]. 6088** But global versions of those functions 6089** must exist in order to be overloaded.)^ 6090** 6091** ^(This API makes sure a global version of a function with a particular 6092** name and number of parameters exists. If no such function exists 6093** before this API is called, a new function is created.)^ ^The implementation 6094** of the new function always causes an exception to be thrown. So 6095** the new function is not good for anything by itself. Its only 6096** purpose is to be a placeholder function that can be overloaded 6097** by a [virtual table]. 6098*/ 6099int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6100 6101/* 6102** The interface to the virtual-table mechanism defined above (back up 6103** to a comment remarkably similar to this one) is currently considered 6104** to be experimental. The interface might change in incompatible ways. 6105** If this is a problem for you, do not use the interface at this time. 6106** 6107** When the virtual-table mechanism stabilizes, we will declare the 6108** interface fixed, support it indefinitely, and remove this comment. 6109*/ 6110 6111/* 6112** CAPI3REF: A Handle To An Open BLOB 6113** KEYWORDS: {BLOB handle} {BLOB handles} 6114** 6115** An instance of this object represents an open BLOB on which 6116** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6117** ^Objects of this type are created by [sqlite3_blob_open()] 6118** and destroyed by [sqlite3_blob_close()]. 6119** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6120** can be used to read or write small subsections of the BLOB. 6121** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6122*/ 6123typedef struct sqlite3_blob sqlite3_blob; 6124 6125/* 6126** CAPI3REF: Open A BLOB For Incremental I/O 6127** METHOD: sqlite3 6128** CONSTRUCTOR: sqlite3_blob 6129** 6130** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6131** in row iRow, column zColumn, table zTable in database zDb; 6132** in other words, the same BLOB that would be selected by: 6133** 6134** <pre> 6135** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6136** </pre>)^ 6137** 6138** ^(Parameter zDb is not the filename that contains the database, but 6139** rather the symbolic name of the database. For attached databases, this is 6140** the name that appears after the AS keyword in the [ATTACH] statement. 6141** For the main database file, the database name is "main". For TEMP 6142** tables, the database name is "temp".)^ 6143** 6144** ^If the flags parameter is non-zero, then the BLOB is opened for read 6145** and write access. ^If the flags parameter is zero, the BLOB is opened for 6146** read-only access. 6147** 6148** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6149** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6150** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6151** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6152** on *ppBlob after this function it returns. 6153** 6154** This function fails with SQLITE_ERROR if any of the following are true: 6155** <ul> 6156** <li> ^(Database zDb does not exist)^, 6157** <li> ^(Table zTable does not exist within database zDb)^, 6158** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6159** <li> ^(Column zColumn does not exist)^, 6160** <li> ^(Row iRow is not present in the table)^, 6161** <li> ^(The specified column of row iRow contains a value that is not 6162** a TEXT or BLOB value)^, 6163** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6164** constraint and the blob is being opened for read/write access)^, 6165** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6166** column zColumn is part of a [child key] definition and the blob is 6167** being opened for read/write access)^. 6168** </ul> 6169** 6170** ^Unless it returns SQLITE_MISUSE, this function sets the 6171** [database connection] error code and message accessible via 6172** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6173** 6174** 6175** ^(If the row that a BLOB handle points to is modified by an 6176** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6177** then the BLOB handle is marked as "expired". 6178** This is true if any column of the row is changed, even a column 6179** other than the one the BLOB handle is open on.)^ 6180** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6181** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6182** ^(Changes written into a BLOB prior to the BLOB expiring are not 6183** rolled back by the expiration of the BLOB. Such changes will eventually 6184** commit if the transaction continues to completion.)^ 6185** 6186** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6187** the opened blob. ^The size of a blob may not be changed by this 6188** interface. Use the [UPDATE] SQL command to change the size of a 6189** blob. 6190** 6191** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6192** and the built-in [zeroblob] SQL function may be used to create a 6193** zero-filled blob to read or write using the incremental-blob interface. 6194** 6195** To avoid a resource leak, every open [BLOB handle] should eventually 6196** be released by a call to [sqlite3_blob_close()]. 6197*/ 6198int sqlite3_blob_open( 6199 sqlite3*, 6200 const char *zDb, 6201 const char *zTable, 6202 const char *zColumn, 6203 sqlite3_int64 iRow, 6204 int flags, 6205 sqlite3_blob **ppBlob 6206); 6207 6208/* 6209** CAPI3REF: Move a BLOB Handle to a New Row 6210** METHOD: sqlite3_blob 6211** 6212** ^This function is used to move an existing blob handle so that it points 6213** to a different row of the same database table. ^The new row is identified 6214** by the rowid value passed as the second argument. Only the row can be 6215** changed. ^The database, table and column on which the blob handle is open 6216** remain the same. Moving an existing blob handle to a new row can be 6217** faster than closing the existing handle and opening a new one. 6218** 6219** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6220** it must exist and there must be either a blob or text value stored in 6221** the nominated column.)^ ^If the new row is not present in the table, or if 6222** it does not contain a blob or text value, or if another error occurs, an 6223** SQLite error code is returned and the blob handle is considered aborted. 6224** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6225** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6226** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6227** always returns zero. 6228** 6229** ^This function sets the database handle error code and message. 6230*/ 6231int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6232 6233/* 6234** CAPI3REF: Close A BLOB Handle 6235** DESTRUCTOR: sqlite3_blob 6236** 6237** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6238** unconditionally. Even if this routine returns an error code, the 6239** handle is still closed.)^ 6240** 6241** ^If the blob handle being closed was opened for read-write access, and if 6242** the database is in auto-commit mode and there are no other open read-write 6243** blob handles or active write statements, the current transaction is 6244** committed. ^If an error occurs while committing the transaction, an error 6245** code is returned and the transaction rolled back. 6246** 6247** Calling this function with an argument that is not a NULL pointer or an 6248** open blob handle results in undefined behaviour. ^Calling this routine 6249** with a null pointer (such as would be returned by a failed call to 6250** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6251** is passed a valid open blob handle, the values returned by the 6252** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6253*/ 6254int sqlite3_blob_close(sqlite3_blob *); 6255 6256/* 6257** CAPI3REF: Return The Size Of An Open BLOB 6258** METHOD: sqlite3_blob 6259** 6260** ^Returns the size in bytes of the BLOB accessible via the 6261** successfully opened [BLOB handle] in its only argument. ^The 6262** incremental blob I/O routines can only read or overwriting existing 6263** blob content; they cannot change the size of a blob. 6264** 6265** This routine only works on a [BLOB handle] which has been created 6266** by a prior successful call to [sqlite3_blob_open()] and which has not 6267** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6268** to this routine results in undefined and probably undesirable behavior. 6269*/ 6270int sqlite3_blob_bytes(sqlite3_blob *); 6271 6272/* 6273** CAPI3REF: Read Data From A BLOB Incrementally 6274** METHOD: sqlite3_blob 6275** 6276** ^(This function is used to read data from an open [BLOB handle] into a 6277** caller-supplied buffer. N bytes of data are copied into buffer Z 6278** from the open BLOB, starting at offset iOffset.)^ 6279** 6280** ^If offset iOffset is less than N bytes from the end of the BLOB, 6281** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6282** less than zero, [SQLITE_ERROR] is returned and no data is read. 6283** ^The size of the blob (and hence the maximum value of N+iOffset) 6284** can be determined using the [sqlite3_blob_bytes()] interface. 6285** 6286** ^An attempt to read from an expired [BLOB handle] fails with an 6287** error code of [SQLITE_ABORT]. 6288** 6289** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6290** Otherwise, an [error code] or an [extended error code] is returned.)^ 6291** 6292** This routine only works on a [BLOB handle] which has been created 6293** by a prior successful call to [sqlite3_blob_open()] and which has not 6294** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6295** to this routine results in undefined and probably undesirable behavior. 6296** 6297** See also: [sqlite3_blob_write()]. 6298*/ 6299int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6300 6301/* 6302** CAPI3REF: Write Data Into A BLOB Incrementally 6303** METHOD: sqlite3_blob 6304** 6305** ^(This function is used to write data into an open [BLOB handle] from a 6306** caller-supplied buffer. N bytes of data are copied from the buffer Z 6307** into the open BLOB, starting at offset iOffset.)^ 6308** 6309** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6310** Otherwise, an [error code] or an [extended error code] is returned.)^ 6311** ^Unless SQLITE_MISUSE is returned, this function sets the 6312** [database connection] error code and message accessible via 6313** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6314** 6315** ^If the [BLOB handle] passed as the first argument was not opened for 6316** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6317** this function returns [SQLITE_READONLY]. 6318** 6319** This function may only modify the contents of the BLOB; it is 6320** not possible to increase the size of a BLOB using this API. 6321** ^If offset iOffset is less than N bytes from the end of the BLOB, 6322** [SQLITE_ERROR] is returned and no data is written. The size of the 6323** BLOB (and hence the maximum value of N+iOffset) can be determined 6324** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6325** than zero [SQLITE_ERROR] is returned and no data is written. 6326** 6327** ^An attempt to write to an expired [BLOB handle] fails with an 6328** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6329** before the [BLOB handle] expired are not rolled back by the 6330** expiration of the handle, though of course those changes might 6331** have been overwritten by the statement that expired the BLOB handle 6332** or by other independent statements. 6333** 6334** This routine only works on a [BLOB handle] which has been created 6335** by a prior successful call to [sqlite3_blob_open()] and which has not 6336** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6337** to this routine results in undefined and probably undesirable behavior. 6338** 6339** See also: [sqlite3_blob_read()]. 6340*/ 6341int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6342 6343/* 6344** CAPI3REF: Virtual File System Objects 6345** 6346** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6347** that SQLite uses to interact 6348** with the underlying operating system. Most SQLite builds come with a 6349** single default VFS that is appropriate for the host computer. 6350** New VFSes can be registered and existing VFSes can be unregistered. 6351** The following interfaces are provided. 6352** 6353** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6354** ^Names are case sensitive. 6355** ^Names are zero-terminated UTF-8 strings. 6356** ^If there is no match, a NULL pointer is returned. 6357** ^If zVfsName is NULL then the default VFS is returned. 6358** 6359** ^New VFSes are registered with sqlite3_vfs_register(). 6360** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6361** ^The same VFS can be registered multiple times without injury. 6362** ^To make an existing VFS into the default VFS, register it again 6363** with the makeDflt flag set. If two different VFSes with the 6364** same name are registered, the behavior is undefined. If a 6365** VFS is registered with a name that is NULL or an empty string, 6366** then the behavior is undefined. 6367** 6368** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6369** ^(If the default VFS is unregistered, another VFS is chosen as 6370** the default. The choice for the new VFS is arbitrary.)^ 6371*/ 6372sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6373int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6374int sqlite3_vfs_unregister(sqlite3_vfs*); 6375 6376/* 6377** CAPI3REF: Mutexes 6378** 6379** The SQLite core uses these routines for thread 6380** synchronization. Though they are intended for internal 6381** use by SQLite, code that links against SQLite is 6382** permitted to use any of these routines. 6383** 6384** The SQLite source code contains multiple implementations 6385** of these mutex routines. An appropriate implementation 6386** is selected automatically at compile-time. The following 6387** implementations are available in the SQLite core: 6388** 6389** <ul> 6390** <li> SQLITE_MUTEX_PTHREADS 6391** <li> SQLITE_MUTEX_W32 6392** <li> SQLITE_MUTEX_NOOP 6393** </ul> 6394** 6395** The SQLITE_MUTEX_NOOP implementation is a set of routines 6396** that does no real locking and is appropriate for use in 6397** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6398** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6399** and Windows. 6400** 6401** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6402** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6403** implementation is included with the library. In this case the 6404** application must supply a custom mutex implementation using the 6405** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6406** before calling sqlite3_initialize() or any other public sqlite3_ 6407** function that calls sqlite3_initialize(). 6408** 6409** ^The sqlite3_mutex_alloc() routine allocates a new 6410** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6411** routine returns NULL if it is unable to allocate the requested 6412** mutex. The argument to sqlite3_mutex_alloc() must one of these 6413** integer constants: 6414** 6415** <ul> 6416** <li> SQLITE_MUTEX_FAST 6417** <li> SQLITE_MUTEX_RECURSIVE 6418** <li> SQLITE_MUTEX_STATIC_MASTER 6419** <li> SQLITE_MUTEX_STATIC_MEM 6420** <li> SQLITE_MUTEX_STATIC_OPEN 6421** <li> SQLITE_MUTEX_STATIC_PRNG 6422** <li> SQLITE_MUTEX_STATIC_LRU 6423** <li> SQLITE_MUTEX_STATIC_PMEM 6424** <li> SQLITE_MUTEX_STATIC_APP1 6425** <li> SQLITE_MUTEX_STATIC_APP2 6426** <li> SQLITE_MUTEX_STATIC_APP3 6427** <li> SQLITE_MUTEX_STATIC_VFS1 6428** <li> SQLITE_MUTEX_STATIC_VFS2 6429** <li> SQLITE_MUTEX_STATIC_VFS3 6430** </ul> 6431** 6432** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6433** cause sqlite3_mutex_alloc() to create 6434** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6435** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6436** The mutex implementation does not need to make a distinction 6437** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6438** not want to. SQLite will only request a recursive mutex in 6439** cases where it really needs one. If a faster non-recursive mutex 6440** implementation is available on the host platform, the mutex subsystem 6441** might return such a mutex in response to SQLITE_MUTEX_FAST. 6442** 6443** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6444** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6445** a pointer to a static preexisting mutex. ^Nine static mutexes are 6446** used by the current version of SQLite. Future versions of SQLite 6447** may add additional static mutexes. Static mutexes are for internal 6448** use by SQLite only. Applications that use SQLite mutexes should 6449** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6450** SQLITE_MUTEX_RECURSIVE. 6451** 6452** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6453** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6454** returns a different mutex on every call. ^For the static 6455** mutex types, the same mutex is returned on every call that has 6456** the same type number. 6457** 6458** ^The sqlite3_mutex_free() routine deallocates a previously 6459** allocated dynamic mutex. Attempting to deallocate a static 6460** mutex results in undefined behavior. 6461** 6462** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6463** to enter a mutex. ^If another thread is already within the mutex, 6464** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6465** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6466** upon successful entry. ^(Mutexes created using 6467** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6468** In such cases, the 6469** mutex must be exited an equal number of times before another thread 6470** can enter.)^ If the same thread tries to enter any mutex other 6471** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6472** 6473** ^(Some systems (for example, Windows 95) do not support the operation 6474** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6475** will always return SQLITE_BUSY. The SQLite core only ever uses 6476** sqlite3_mutex_try() as an optimization so this is acceptable 6477** behavior.)^ 6478** 6479** ^The sqlite3_mutex_leave() routine exits a mutex that was 6480** previously entered by the same thread. The behavior 6481** is undefined if the mutex is not currently entered by the 6482** calling thread or is not currently allocated. 6483** 6484** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6485** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6486** behave as no-ops. 6487** 6488** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6489*/ 6490sqlite3_mutex *sqlite3_mutex_alloc(int); 6491void sqlite3_mutex_free(sqlite3_mutex*); 6492void sqlite3_mutex_enter(sqlite3_mutex*); 6493int sqlite3_mutex_try(sqlite3_mutex*); 6494void sqlite3_mutex_leave(sqlite3_mutex*); 6495 6496/* 6497** CAPI3REF: Mutex Methods Object 6498** 6499** An instance of this structure defines the low-level routines 6500** used to allocate and use mutexes. 6501** 6502** Usually, the default mutex implementations provided by SQLite are 6503** sufficient, however the application has the option of substituting a custom 6504** implementation for specialized deployments or systems for which SQLite 6505** does not provide a suitable implementation. In this case, the application 6506** creates and populates an instance of this structure to pass 6507** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6508** Additionally, an instance of this structure can be used as an 6509** output variable when querying the system for the current mutex 6510** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6511** 6512** ^The xMutexInit method defined by this structure is invoked as 6513** part of system initialization by the sqlite3_initialize() function. 6514** ^The xMutexInit routine is called by SQLite exactly once for each 6515** effective call to [sqlite3_initialize()]. 6516** 6517** ^The xMutexEnd method defined by this structure is invoked as 6518** part of system shutdown by the sqlite3_shutdown() function. The 6519** implementation of this method is expected to release all outstanding 6520** resources obtained by the mutex methods implementation, especially 6521** those obtained by the xMutexInit method. ^The xMutexEnd() 6522** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6523** 6524** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6525** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6526** xMutexNotheld) implement the following interfaces (respectively): 6527** 6528** <ul> 6529** <li> [sqlite3_mutex_alloc()] </li> 6530** <li> [sqlite3_mutex_free()] </li> 6531** <li> [sqlite3_mutex_enter()] </li> 6532** <li> [sqlite3_mutex_try()] </li> 6533** <li> [sqlite3_mutex_leave()] </li> 6534** <li> [sqlite3_mutex_held()] </li> 6535** <li> [sqlite3_mutex_notheld()] </li> 6536** </ul>)^ 6537** 6538** The only difference is that the public sqlite3_XXX functions enumerated 6539** above silently ignore any invocations that pass a NULL pointer instead 6540** of a valid mutex handle. The implementations of the methods defined 6541** by this structure are not required to handle this case, the results 6542** of passing a NULL pointer instead of a valid mutex handle are undefined 6543** (i.e. it is acceptable to provide an implementation that segfaults if 6544** it is passed a NULL pointer). 6545** 6546** The xMutexInit() method must be threadsafe. It must be harmless to 6547** invoke xMutexInit() multiple times within the same process and without 6548** intervening calls to xMutexEnd(). Second and subsequent calls to 6549** xMutexInit() must be no-ops. 6550** 6551** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6552** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6553** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6554** memory allocation for a fast or recursive mutex. 6555** 6556** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6557** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6558** If xMutexInit fails in any way, it is expected to clean up after itself 6559** prior to returning. 6560*/ 6561typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6562struct sqlite3_mutex_methods { 6563 int (*xMutexInit)(void); 6564 int (*xMutexEnd)(void); 6565 sqlite3_mutex *(*xMutexAlloc)(int); 6566 void (*xMutexFree)(sqlite3_mutex *); 6567 void (*xMutexEnter)(sqlite3_mutex *); 6568 int (*xMutexTry)(sqlite3_mutex *); 6569 void (*xMutexLeave)(sqlite3_mutex *); 6570 int (*xMutexHeld)(sqlite3_mutex *); 6571 int (*xMutexNotheld)(sqlite3_mutex *); 6572}; 6573 6574/* 6575** CAPI3REF: Mutex Verification Routines 6576** 6577** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6578** are intended for use inside assert() statements. The SQLite core 6579** never uses these routines except inside an assert() and applications 6580** are advised to follow the lead of the core. The SQLite core only 6581** provides implementations for these routines when it is compiled 6582** with the SQLITE_DEBUG flag. External mutex implementations 6583** are only required to provide these routines if SQLITE_DEBUG is 6584** defined and if NDEBUG is not defined. 6585** 6586** These routines should return true if the mutex in their argument 6587** is held or not held, respectively, by the calling thread. 6588** 6589** The implementation is not required to provide versions of these 6590** routines that actually work. If the implementation does not provide working 6591** versions of these routines, it should at least provide stubs that always 6592** return true so that one does not get spurious assertion failures. 6593** 6594** If the argument to sqlite3_mutex_held() is a NULL pointer then 6595** the routine should return 1. This seems counter-intuitive since 6596** clearly the mutex cannot be held if it does not exist. But 6597** the reason the mutex does not exist is because the build is not 6598** using mutexes. And we do not want the assert() containing the 6599** call to sqlite3_mutex_held() to fail, so a non-zero return is 6600** the appropriate thing to do. The sqlite3_mutex_notheld() 6601** interface should also return 1 when given a NULL pointer. 6602*/ 6603#ifndef NDEBUG 6604int sqlite3_mutex_held(sqlite3_mutex*); 6605int sqlite3_mutex_notheld(sqlite3_mutex*); 6606#endif 6607 6608/* 6609** CAPI3REF: Mutex Types 6610** 6611** The [sqlite3_mutex_alloc()] interface takes a single argument 6612** which is one of these integer constants. 6613** 6614** The set of static mutexes may change from one SQLite release to the 6615** next. Applications that override the built-in mutex logic must be 6616** prepared to accommodate additional static mutexes. 6617*/ 6618#define SQLITE_MUTEX_FAST 0 6619#define SQLITE_MUTEX_RECURSIVE 1 6620#define SQLITE_MUTEX_STATIC_MASTER 2 6621#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6622#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6623#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6624#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6625#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6626#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6627#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6628#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6629#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6630#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6631#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6632#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6633#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6634 6635/* 6636** CAPI3REF: Retrieve the mutex for a database connection 6637** METHOD: sqlite3 6638** 6639** ^This interface returns a pointer the [sqlite3_mutex] object that 6640** serializes access to the [database connection] given in the argument 6641** when the [threading mode] is Serialized. 6642** ^If the [threading mode] is Single-thread or Multi-thread then this 6643** routine returns a NULL pointer. 6644*/ 6645sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6646 6647/* 6648** CAPI3REF: Low-Level Control Of Database Files 6649** METHOD: sqlite3 6650** 6651** ^The [sqlite3_file_control()] interface makes a direct call to the 6652** xFileControl method for the [sqlite3_io_methods] object associated 6653** with a particular database identified by the second argument. ^The 6654** name of the database is "main" for the main database or "temp" for the 6655** TEMP database, or the name that appears after the AS keyword for 6656** databases that are added using the [ATTACH] SQL command. 6657** ^A NULL pointer can be used in place of "main" to refer to the 6658** main database file. 6659** ^The third and fourth parameters to this routine 6660** are passed directly through to the second and third parameters of 6661** the xFileControl method. ^The return value of the xFileControl 6662** method becomes the return value of this routine. 6663** 6664** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6665** a pointer to the underlying [sqlite3_file] object to be written into 6666** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6667** case is a short-circuit path which does not actually invoke the 6668** underlying sqlite3_io_methods.xFileControl method. 6669** 6670** ^If the second parameter (zDbName) does not match the name of any 6671** open database file, then SQLITE_ERROR is returned. ^This error 6672** code is not remembered and will not be recalled by [sqlite3_errcode()] 6673** or [sqlite3_errmsg()]. The underlying xFileControl method might 6674** also return SQLITE_ERROR. There is no way to distinguish between 6675** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6676** xFileControl method. 6677** 6678** See also: [SQLITE_FCNTL_LOCKSTATE] 6679*/ 6680int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6681 6682/* 6683** CAPI3REF: Testing Interface 6684** 6685** ^The sqlite3_test_control() interface is used to read out internal 6686** state of SQLite and to inject faults into SQLite for testing 6687** purposes. ^The first parameter is an operation code that determines 6688** the number, meaning, and operation of all subsequent parameters. 6689** 6690** This interface is not for use by applications. It exists solely 6691** for verifying the correct operation of the SQLite library. Depending 6692** on how the SQLite library is compiled, this interface might not exist. 6693** 6694** The details of the operation codes, their meanings, the parameters 6695** they take, and what they do are all subject to change without notice. 6696** Unlike most of the SQLite API, this function is not guaranteed to 6697** operate consistently from one release to the next. 6698*/ 6699int sqlite3_test_control(int op, ...); 6700 6701/* 6702** CAPI3REF: Testing Interface Operation Codes 6703** 6704** These constants are the valid operation code parameters used 6705** as the first argument to [sqlite3_test_control()]. 6706** 6707** These parameters and their meanings are subject to change 6708** without notice. These values are for testing purposes only. 6709** Applications should not use any of these parameters or the 6710** [sqlite3_test_control()] interface. 6711*/ 6712#define SQLITE_TESTCTRL_FIRST 5 6713#define SQLITE_TESTCTRL_PRNG_SAVE 5 6714#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6715#define SQLITE_TESTCTRL_PRNG_RESET 7 6716#define SQLITE_TESTCTRL_BITVEC_TEST 8 6717#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6718#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6719#define SQLITE_TESTCTRL_PENDING_BYTE 11 6720#define SQLITE_TESTCTRL_ASSERT 12 6721#define SQLITE_TESTCTRL_ALWAYS 13 6722#define SQLITE_TESTCTRL_RESERVE 14 6723#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 6724#define SQLITE_TESTCTRL_ISKEYWORD 16 6725#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 6726#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 6727#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 6728#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 6729#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 6730#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 6731#define SQLITE_TESTCTRL_BYTEORDER 22 6732#define SQLITE_TESTCTRL_ISINIT 23 6733#define SQLITE_TESTCTRL_SORTER_MMAP 24 6734#define SQLITE_TESTCTRL_IMPOSTER 25 6735#define SQLITE_TESTCTRL_LAST 25 6736 6737/* 6738** CAPI3REF: SQLite Runtime Status 6739** 6740** ^These interfaces are used to retrieve runtime status information 6741** about the performance of SQLite, and optionally to reset various 6742** highwater marks. ^The first argument is an integer code for 6743** the specific parameter to measure. ^(Recognized integer codes 6744** are of the form [status parameters | SQLITE_STATUS_...].)^ 6745** ^The current value of the parameter is returned into *pCurrent. 6746** ^The highest recorded value is returned in *pHighwater. ^If the 6747** resetFlag is true, then the highest record value is reset after 6748** *pHighwater is written. ^(Some parameters do not record the highest 6749** value. For those parameters 6750** nothing is written into *pHighwater and the resetFlag is ignored.)^ 6751** ^(Other parameters record only the highwater mark and not the current 6752** value. For these latter parameters nothing is written into *pCurrent.)^ 6753** 6754** ^The sqlite3_status() and sqlite3_status64() routines return 6755** SQLITE_OK on success and a non-zero [error code] on failure. 6756** 6757** If either the current value or the highwater mark is too large to 6758** be represented by a 32-bit integer, then the values returned by 6759** sqlite3_status() are undefined. 6760** 6761** See also: [sqlite3_db_status()] 6762*/ 6763int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 6764int sqlite3_status64( 6765 int op, 6766 sqlite3_int64 *pCurrent, 6767 sqlite3_int64 *pHighwater, 6768 int resetFlag 6769); 6770 6771 6772/* 6773** CAPI3REF: Status Parameters 6774** KEYWORDS: {status parameters} 6775** 6776** These integer constants designate various run-time status parameters 6777** that can be returned by [sqlite3_status()]. 6778** 6779** <dl> 6780** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 6781** <dd>This parameter is the current amount of memory checked out 6782** using [sqlite3_malloc()], either directly or indirectly. The 6783** figure includes calls made to [sqlite3_malloc()] by the application 6784** and internal memory usage by the SQLite library. Scratch memory 6785** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 6786** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 6787** this parameter. The amount returned is the sum of the allocation 6788** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 6789** 6790** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 6791** <dd>This parameter records the largest memory allocation request 6792** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 6793** internal equivalents). Only the value returned in the 6794** *pHighwater parameter to [sqlite3_status()] is of interest. 6795** The value written into the *pCurrent parameter is undefined.</dd>)^ 6796** 6797** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 6798** <dd>This parameter records the number of separate memory allocations 6799** currently checked out.</dd>)^ 6800** 6801** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 6802** <dd>This parameter returns the number of pages used out of the 6803** [pagecache memory allocator] that was configured using 6804** [SQLITE_CONFIG_PAGECACHE]. The 6805** value returned is in pages, not in bytes.</dd>)^ 6806** 6807** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 6808** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 6809** <dd>This parameter returns the number of bytes of page cache 6810** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 6811** buffer and where forced to overflow to [sqlite3_malloc()]. The 6812** returned value includes allocations that overflowed because they 6813** where too large (they were larger than the "sz" parameter to 6814** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 6815** no space was left in the page cache.</dd>)^ 6816** 6817** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 6818** <dd>This parameter records the largest memory allocation request 6819** handed to [pagecache memory allocator]. Only the value returned in the 6820** *pHighwater parameter to [sqlite3_status()] is of interest. 6821** The value written into the *pCurrent parameter is undefined.</dd>)^ 6822** 6823** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 6824** <dd>This parameter returns the number of allocations used out of the 6825** [scratch memory allocator] configured using 6826** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 6827** in bytes. Since a single thread may only have one scratch allocation 6828** outstanding at time, this parameter also reports the number of threads 6829** using scratch memory at the same time.</dd>)^ 6830** 6831** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 6832** <dd>This parameter returns the number of bytes of scratch memory 6833** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 6834** buffer and where forced to overflow to [sqlite3_malloc()]. The values 6835** returned include overflows because the requested allocation was too 6836** larger (that is, because the requested allocation was larger than the 6837** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 6838** slots were available. 6839** </dd>)^ 6840** 6841** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 6842** <dd>This parameter records the largest memory allocation request 6843** handed to [scratch memory allocator]. Only the value returned in the 6844** *pHighwater parameter to [sqlite3_status()] is of interest. 6845** The value written into the *pCurrent parameter is undefined.</dd>)^ 6846** 6847** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 6848** <dd>The *pHighwater parameter records the deepest parser stack. 6849** The *pCurrent value is undefined. The *pHighwater value is only 6850** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 6851** </dl> 6852** 6853** New status parameters may be added from time to time. 6854*/ 6855#define SQLITE_STATUS_MEMORY_USED 0 6856#define SQLITE_STATUS_PAGECACHE_USED 1 6857#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 6858#define SQLITE_STATUS_SCRATCH_USED 3 6859#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 6860#define SQLITE_STATUS_MALLOC_SIZE 5 6861#define SQLITE_STATUS_PARSER_STACK 6 6862#define SQLITE_STATUS_PAGECACHE_SIZE 7 6863#define SQLITE_STATUS_SCRATCH_SIZE 8 6864#define SQLITE_STATUS_MALLOC_COUNT 9 6865 6866/* 6867** CAPI3REF: Database Connection Status 6868** METHOD: sqlite3 6869** 6870** ^This interface is used to retrieve runtime status information 6871** about a single [database connection]. ^The first argument is the 6872** database connection object to be interrogated. ^The second argument 6873** is an integer constant, taken from the set of 6874** [SQLITE_DBSTATUS options], that 6875** determines the parameter to interrogate. The set of 6876** [SQLITE_DBSTATUS options] is likely 6877** to grow in future releases of SQLite. 6878** 6879** ^The current value of the requested parameter is written into *pCur 6880** and the highest instantaneous value is written into *pHiwtr. ^If 6881** the resetFlg is true, then the highest instantaneous value is 6882** reset back down to the current value. 6883** 6884** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 6885** non-zero [error code] on failure. 6886** 6887** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 6888*/ 6889int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 6890 6891/* 6892** CAPI3REF: Status Parameters for database connections 6893** KEYWORDS: {SQLITE_DBSTATUS options} 6894** 6895** These constants are the available integer "verbs" that can be passed as 6896** the second argument to the [sqlite3_db_status()] interface. 6897** 6898** New verbs may be added in future releases of SQLite. Existing verbs 6899** might be discontinued. Applications should check the return code from 6900** [sqlite3_db_status()] to make sure that the call worked. 6901** The [sqlite3_db_status()] interface will return a non-zero error code 6902** if a discontinued or unsupported verb is invoked. 6903** 6904** <dl> 6905** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 6906** <dd>This parameter returns the number of lookaside memory slots currently 6907** checked out.</dd>)^ 6908** 6909** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 6910** <dd>This parameter returns the number malloc attempts that were 6911** satisfied using lookaside memory. Only the high-water value is meaningful; 6912** the current value is always zero.)^ 6913** 6914** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 6915** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 6916** <dd>This parameter returns the number malloc attempts that might have 6917** been satisfied using lookaside memory but failed due to the amount of 6918** memory requested being larger than the lookaside slot size. 6919** Only the high-water value is meaningful; 6920** the current value is always zero.)^ 6921** 6922** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 6923** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 6924** <dd>This parameter returns the number malloc attempts that might have 6925** been satisfied using lookaside memory but failed due to all lookaside 6926** memory already being in use. 6927** Only the high-water value is meaningful; 6928** the current value is always zero.)^ 6929** 6930** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 6931** <dd>This parameter returns the approximate number of bytes of heap 6932** memory used by all pager caches associated with the database connection.)^ 6933** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 6934** 6935** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 6936** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 6937** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 6938** pager cache is shared between two or more connections the bytes of heap 6939** memory used by that pager cache is divided evenly between the attached 6940** connections.)^ In other words, if none of the pager caches associated 6941** with the database connection are shared, this request returns the same 6942** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 6943** shared, the value returned by this call will be smaller than that returned 6944** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 6945** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 6946** 6947** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 6948** <dd>This parameter returns the approximate number of bytes of heap 6949** memory used to store the schema for all databases associated 6950** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 6951** ^The full amount of memory used by the schemas is reported, even if the 6952** schema memory is shared with other database connections due to 6953** [shared cache mode] being enabled. 6954** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 6955** 6956** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 6957** <dd>This parameter returns the approximate number of bytes of heap 6958** and lookaside memory used by all prepared statements associated with 6959** the database connection.)^ 6960** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 6961** </dd> 6962** 6963** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 6964** <dd>This parameter returns the number of pager cache hits that have 6965** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6966** is always 0. 6967** </dd> 6968** 6969** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6970** <dd>This parameter returns the number of pager cache misses that have 6971** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6972** is always 0. 6973** </dd> 6974** 6975** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 6976** <dd>This parameter returns the number of dirty cache entries that have 6977** been written to disk. Specifically, the number of pages written to the 6978** wal file in wal mode databases, or the number of pages written to the 6979** database file in rollback mode databases. Any pages written as part of 6980** transaction rollback or database recovery operations are not included. 6981** If an IO or other error occurs while writing a page to disk, the effect 6982** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 6983** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 6984** </dd> 6985** 6986** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 6987** <dd>This parameter returns zero for the current value if and only if 6988** all foreign key constraints (deferred or immediate) have been 6989** resolved.)^ ^The highwater mark is always 0. 6990** </dd> 6991** </dl> 6992*/ 6993#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6994#define SQLITE_DBSTATUS_CACHE_USED 1 6995#define SQLITE_DBSTATUS_SCHEMA_USED 2 6996#define SQLITE_DBSTATUS_STMT_USED 3 6997#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6998#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6999#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7000#define SQLITE_DBSTATUS_CACHE_HIT 7 7001#define SQLITE_DBSTATUS_CACHE_MISS 8 7002#define SQLITE_DBSTATUS_CACHE_WRITE 9 7003#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7004#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7005#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7006 7007 7008/* 7009** CAPI3REF: Prepared Statement Status 7010** METHOD: sqlite3_stmt 7011** 7012** ^(Each prepared statement maintains various 7013** [SQLITE_STMTSTATUS counters] that measure the number 7014** of times it has performed specific operations.)^ These counters can 7015** be used to monitor the performance characteristics of the prepared 7016** statements. For example, if the number of table steps greatly exceeds 7017** the number of table searches or result rows, that would tend to indicate 7018** that the prepared statement is using a full table scan rather than 7019** an index. 7020** 7021** ^(This interface is used to retrieve and reset counter values from 7022** a [prepared statement]. The first argument is the prepared statement 7023** object to be interrogated. The second argument 7024** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7025** to be interrogated.)^ 7026** ^The current value of the requested counter is returned. 7027** ^If the resetFlg is true, then the counter is reset to zero after this 7028** interface call returns. 7029** 7030** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7031*/ 7032int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7033 7034/* 7035** CAPI3REF: Status Parameters for prepared statements 7036** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7037** 7038** These preprocessor macros define integer codes that name counter 7039** values associated with the [sqlite3_stmt_status()] interface. 7040** The meanings of the various counters are as follows: 7041** 7042** <dl> 7043** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7044** <dd>^This is the number of times that SQLite has stepped forward in 7045** a table as part of a full table scan. Large numbers for this counter 7046** may indicate opportunities for performance improvement through 7047** careful use of indices.</dd> 7048** 7049** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7050** <dd>^This is the number of sort operations that have occurred. 7051** A non-zero value in this counter may indicate an opportunity to 7052** improvement performance through careful use of indices.</dd> 7053** 7054** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7055** <dd>^This is the number of rows inserted into transient indices that 7056** were created automatically in order to help joins run faster. 7057** A non-zero value in this counter may indicate an opportunity to 7058** improvement performance by adding permanent indices that do not 7059** need to be reinitialized each time the statement is run.</dd> 7060** 7061** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7062** <dd>^This is the number of virtual machine operations executed 7063** by the prepared statement if that number is less than or equal 7064** to 2147483647. The number of virtual machine operations can be 7065** used as a proxy for the total work done by the prepared statement. 7066** If the number of virtual machine operations exceeds 2147483647 7067** then the value returned by this statement status code is undefined. 7068** </dd> 7069** </dl> 7070*/ 7071#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7072#define SQLITE_STMTSTATUS_SORT 2 7073#define SQLITE_STMTSTATUS_AUTOINDEX 3 7074#define SQLITE_STMTSTATUS_VM_STEP 4 7075 7076/* 7077** CAPI3REF: Custom Page Cache Object 7078** 7079** The sqlite3_pcache type is opaque. It is implemented by 7080** the pluggable module. The SQLite core has no knowledge of 7081** its size or internal structure and never deals with the 7082** sqlite3_pcache object except by holding and passing pointers 7083** to the object. 7084** 7085** See [sqlite3_pcache_methods2] for additional information. 7086*/ 7087typedef struct sqlite3_pcache sqlite3_pcache; 7088 7089/* 7090** CAPI3REF: Custom Page Cache Object 7091** 7092** The sqlite3_pcache_page object represents a single page in the 7093** page cache. The page cache will allocate instances of this 7094** object. Various methods of the page cache use pointers to instances 7095** of this object as parameters or as their return value. 7096** 7097** See [sqlite3_pcache_methods2] for additional information. 7098*/ 7099typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7100struct sqlite3_pcache_page { 7101 void *pBuf; /* The content of the page */ 7102 void *pExtra; /* Extra information associated with the page */ 7103}; 7104 7105/* 7106** CAPI3REF: Application Defined Page Cache. 7107** KEYWORDS: {page cache} 7108** 7109** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7110** register an alternative page cache implementation by passing in an 7111** instance of the sqlite3_pcache_methods2 structure.)^ 7112** In many applications, most of the heap memory allocated by 7113** SQLite is used for the page cache. 7114** By implementing a 7115** custom page cache using this API, an application can better control 7116** the amount of memory consumed by SQLite, the way in which 7117** that memory is allocated and released, and the policies used to 7118** determine exactly which parts of a database file are cached and for 7119** how long. 7120** 7121** The alternative page cache mechanism is an 7122** extreme measure that is only needed by the most demanding applications. 7123** The built-in page cache is recommended for most uses. 7124** 7125** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7126** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7127** the application may discard the parameter after the call to 7128** [sqlite3_config()] returns.)^ 7129** 7130** [[the xInit() page cache method]] 7131** ^(The xInit() method is called once for each effective 7132** call to [sqlite3_initialize()])^ 7133** (usually only once during the lifetime of the process). ^(The xInit() 7134** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7135** The intent of the xInit() method is to set up global data structures 7136** required by the custom page cache implementation. 7137** ^(If the xInit() method is NULL, then the 7138** built-in default page cache is used instead of the application defined 7139** page cache.)^ 7140** 7141** [[the xShutdown() page cache method]] 7142** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7143** It can be used to clean up 7144** any outstanding resources before process shutdown, if required. 7145** ^The xShutdown() method may be NULL. 7146** 7147** ^SQLite automatically serializes calls to the xInit method, 7148** so the xInit method need not be threadsafe. ^The 7149** xShutdown method is only called from [sqlite3_shutdown()] so it does 7150** not need to be threadsafe either. All other methods must be threadsafe 7151** in multithreaded applications. 7152** 7153** ^SQLite will never invoke xInit() more than once without an intervening 7154** call to xShutdown(). 7155** 7156** [[the xCreate() page cache methods]] 7157** ^SQLite invokes the xCreate() method to construct a new cache instance. 7158** SQLite will typically create one cache instance for each open database file, 7159** though this is not guaranteed. ^The 7160** first parameter, szPage, is the size in bytes of the pages that must 7161** be allocated by the cache. ^szPage will always a power of two. ^The 7162** second parameter szExtra is a number of bytes of extra storage 7163** associated with each page cache entry. ^The szExtra parameter will 7164** a number less than 250. SQLite will use the 7165** extra szExtra bytes on each page to store metadata about the underlying 7166** database page on disk. The value passed into szExtra depends 7167** on the SQLite version, the target platform, and how SQLite was compiled. 7168** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7169** created will be used to cache database pages of a file stored on disk, or 7170** false if it is used for an in-memory database. The cache implementation 7171** does not have to do anything special based with the value of bPurgeable; 7172** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7173** never invoke xUnpin() except to deliberately delete a page. 7174** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7175** false will always have the "discard" flag set to true. 7176** ^Hence, a cache created with bPurgeable false will 7177** never contain any unpinned pages. 7178** 7179** [[the xCachesize() page cache method]] 7180** ^(The xCachesize() method may be called at any time by SQLite to set the 7181** suggested maximum cache-size (number of pages stored by) the cache 7182** instance passed as the first argument. This is the value configured using 7183** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7184** parameter, the implementation is not required to do anything with this 7185** value; it is advisory only. 7186** 7187** [[the xPagecount() page cache methods]] 7188** The xPagecount() method must return the number of pages currently 7189** stored in the cache, both pinned and unpinned. 7190** 7191** [[the xFetch() page cache methods]] 7192** The xFetch() method locates a page in the cache and returns a pointer to 7193** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7194** The pBuf element of the returned sqlite3_pcache_page object will be a 7195** pointer to a buffer of szPage bytes used to store the content of a 7196** single database page. The pExtra element of sqlite3_pcache_page will be 7197** a pointer to the szExtra bytes of extra storage that SQLite has requested 7198** for each entry in the page cache. 7199** 7200** The page to be fetched is determined by the key. ^The minimum key value 7201** is 1. After it has been retrieved using xFetch, the page is considered 7202** to be "pinned". 7203** 7204** If the requested page is already in the page cache, then the page cache 7205** implementation must return a pointer to the page buffer with its content 7206** intact. If the requested page is not already in the cache, then the 7207** cache implementation should use the value of the createFlag 7208** parameter to help it determined what action to take: 7209** 7210** <table border=1 width=85% align=center> 7211** <tr><th> createFlag <th> Behavior when page is not already in cache 7212** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7213** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7214** Otherwise return NULL. 7215** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7216** NULL if allocating a new page is effectively impossible. 7217** </table> 7218** 7219** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7220** will only use a createFlag of 2 after a prior call with a createFlag of 1 7221** failed.)^ In between the to xFetch() calls, SQLite may 7222** attempt to unpin one or more cache pages by spilling the content of 7223** pinned pages to disk and synching the operating system disk cache. 7224** 7225** [[the xUnpin() page cache method]] 7226** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7227** as its second argument. If the third parameter, discard, is non-zero, 7228** then the page must be evicted from the cache. 7229** ^If the discard parameter is 7230** zero, then the page may be discarded or retained at the discretion of 7231** page cache implementation. ^The page cache implementation 7232** may choose to evict unpinned pages at any time. 7233** 7234** The cache must not perform any reference counting. A single 7235** call to xUnpin() unpins the page regardless of the number of prior calls 7236** to xFetch(). 7237** 7238** [[the xRekey() page cache methods]] 7239** The xRekey() method is used to change the key value associated with the 7240** page passed as the second argument. If the cache 7241** previously contains an entry associated with newKey, it must be 7242** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7243** to be pinned. 7244** 7245** When SQLite calls the xTruncate() method, the cache must discard all 7246** existing cache entries with page numbers (keys) greater than or equal 7247** to the value of the iLimit parameter passed to xTruncate(). If any 7248** of these pages are pinned, they are implicitly unpinned, meaning that 7249** they can be safely discarded. 7250** 7251** [[the xDestroy() page cache method]] 7252** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7253** All resources associated with the specified cache should be freed. ^After 7254** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7255** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7256** functions. 7257** 7258** [[the xShrink() page cache method]] 7259** ^SQLite invokes the xShrink() method when it wants the page cache to 7260** free up as much of heap memory as possible. The page cache implementation 7261** is not obligated to free any memory, but well-behaved implementations should 7262** do their best. 7263*/ 7264typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7265struct sqlite3_pcache_methods2 { 7266 int iVersion; 7267 void *pArg; 7268 int (*xInit)(void*); 7269 void (*xShutdown)(void*); 7270 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7271 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7272 int (*xPagecount)(sqlite3_pcache*); 7273 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7274 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7275 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7276 unsigned oldKey, unsigned newKey); 7277 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7278 void (*xDestroy)(sqlite3_pcache*); 7279 void (*xShrink)(sqlite3_pcache*); 7280}; 7281 7282/* 7283** This is the obsolete pcache_methods object that has now been replaced 7284** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7285** retained in the header file for backwards compatibility only. 7286*/ 7287typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7288struct sqlite3_pcache_methods { 7289 void *pArg; 7290 int (*xInit)(void*); 7291 void (*xShutdown)(void*); 7292 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7293 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7294 int (*xPagecount)(sqlite3_pcache*); 7295 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7296 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7297 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7298 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7299 void (*xDestroy)(sqlite3_pcache*); 7300}; 7301 7302 7303/* 7304** CAPI3REF: Online Backup Object 7305** 7306** The sqlite3_backup object records state information about an ongoing 7307** online backup operation. ^The sqlite3_backup object is created by 7308** a call to [sqlite3_backup_init()] and is destroyed by a call to 7309** [sqlite3_backup_finish()]. 7310** 7311** See Also: [Using the SQLite Online Backup API] 7312*/ 7313typedef struct sqlite3_backup sqlite3_backup; 7314 7315/* 7316** CAPI3REF: Online Backup API. 7317** 7318** The backup API copies the content of one database into another. 7319** It is useful either for creating backups of databases or 7320** for copying in-memory databases to or from persistent files. 7321** 7322** See Also: [Using the SQLite Online Backup API] 7323** 7324** ^SQLite holds a write transaction open on the destination database file 7325** for the duration of the backup operation. 7326** ^The source database is read-locked only while it is being read; 7327** it is not locked continuously for the entire backup operation. 7328** ^Thus, the backup may be performed on a live source database without 7329** preventing other database connections from 7330** reading or writing to the source database while the backup is underway. 7331** 7332** ^(To perform a backup operation: 7333** <ol> 7334** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7335** backup, 7336** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7337** the data between the two databases, and finally 7338** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7339** associated with the backup operation. 7340** </ol>)^ 7341** There should be exactly one call to sqlite3_backup_finish() for each 7342** successful call to sqlite3_backup_init(). 7343** 7344** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7345** 7346** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7347** [database connection] associated with the destination database 7348** and the database name, respectively. 7349** ^The database name is "main" for the main database, "temp" for the 7350** temporary database, or the name specified after the AS keyword in 7351** an [ATTACH] statement for an attached database. 7352** ^The S and M arguments passed to 7353** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7354** and database name of the source database, respectively. 7355** ^The source and destination [database connections] (parameters S and D) 7356** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7357** an error. 7358** 7359** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7360** there is already a read or read-write transaction open on the 7361** destination database. 7362** 7363** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7364** returned and an error code and error message are stored in the 7365** destination [database connection] D. 7366** ^The error code and message for the failed call to sqlite3_backup_init() 7367** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7368** [sqlite3_errmsg16()] functions. 7369** ^A successful call to sqlite3_backup_init() returns a pointer to an 7370** [sqlite3_backup] object. 7371** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7372** sqlite3_backup_finish() functions to perform the specified backup 7373** operation. 7374** 7375** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7376** 7377** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7378** the source and destination databases specified by [sqlite3_backup] object B. 7379** ^If N is negative, all remaining source pages are copied. 7380** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7381** are still more pages to be copied, then the function returns [SQLITE_OK]. 7382** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7383** from source to destination, then it returns [SQLITE_DONE]. 7384** ^If an error occurs while running sqlite3_backup_step(B,N), 7385** then an [error code] is returned. ^As well as [SQLITE_OK] and 7386** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7387** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7388** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7389** 7390** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7391** <ol> 7392** <li> the destination database was opened read-only, or 7393** <li> the destination database is using write-ahead-log journaling 7394** and the destination and source page sizes differ, or 7395** <li> the destination database is an in-memory database and the 7396** destination and source page sizes differ. 7397** </ol>)^ 7398** 7399** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7400** the [sqlite3_busy_handler | busy-handler function] 7401** is invoked (if one is specified). ^If the 7402** busy-handler returns non-zero before the lock is available, then 7403** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7404** sqlite3_backup_step() can be retried later. ^If the source 7405** [database connection] 7406** is being used to write to the source database when sqlite3_backup_step() 7407** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7408** case the call to sqlite3_backup_step() can be retried later on. ^(If 7409** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7410** [SQLITE_READONLY] is returned, then 7411** there is no point in retrying the call to sqlite3_backup_step(). These 7412** errors are considered fatal.)^ The application must accept 7413** that the backup operation has failed and pass the backup operation handle 7414** to the sqlite3_backup_finish() to release associated resources. 7415** 7416** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7417** on the destination file. ^The exclusive lock is not released until either 7418** sqlite3_backup_finish() is called or the backup operation is complete 7419** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7420** sqlite3_backup_step() obtains a [shared lock] on the source database that 7421** lasts for the duration of the sqlite3_backup_step() call. 7422** ^Because the source database is not locked between calls to 7423** sqlite3_backup_step(), the source database may be modified mid-way 7424** through the backup process. ^If the source database is modified by an 7425** external process or via a database connection other than the one being 7426** used by the backup operation, then the backup will be automatically 7427** restarted by the next call to sqlite3_backup_step(). ^If the source 7428** database is modified by the using the same database connection as is used 7429** by the backup operation, then the backup database is automatically 7430** updated at the same time. 7431** 7432** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7433** 7434** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7435** application wishes to abandon the backup operation, the application 7436** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7437** ^The sqlite3_backup_finish() interfaces releases all 7438** resources associated with the [sqlite3_backup] object. 7439** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7440** active write-transaction on the destination database is rolled back. 7441** The [sqlite3_backup] object is invalid 7442** and may not be used following a call to sqlite3_backup_finish(). 7443** 7444** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7445** sqlite3_backup_step() errors occurred, regardless or whether or not 7446** sqlite3_backup_step() completed. 7447** ^If an out-of-memory condition or IO error occurred during any prior 7448** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7449** sqlite3_backup_finish() returns the corresponding [error code]. 7450** 7451** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7452** is not a permanent error and does not affect the return value of 7453** sqlite3_backup_finish(). 7454** 7455** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7456** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7457** 7458** ^The sqlite3_backup_remaining() routine returns the number of pages still 7459** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7460** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7461** in the source database at the conclusion of the most recent 7462** sqlite3_backup_step(). 7463** ^(The values returned by these functions are only updated by 7464** sqlite3_backup_step(). If the source database is modified in a way that 7465** changes the size of the source database or the number of pages remaining, 7466** those changes are not reflected in the output of sqlite3_backup_pagecount() 7467** and sqlite3_backup_remaining() until after the next 7468** sqlite3_backup_step().)^ 7469** 7470** <b>Concurrent Usage of Database Handles</b> 7471** 7472** ^The source [database connection] may be used by the application for other 7473** purposes while a backup operation is underway or being initialized. 7474** ^If SQLite is compiled and configured to support threadsafe database 7475** connections, then the source database connection may be used concurrently 7476** from within other threads. 7477** 7478** However, the application must guarantee that the destination 7479** [database connection] is not passed to any other API (by any thread) after 7480** sqlite3_backup_init() is called and before the corresponding call to 7481** sqlite3_backup_finish(). SQLite does not currently check to see 7482** if the application incorrectly accesses the destination [database connection] 7483** and so no error code is reported, but the operations may malfunction 7484** nevertheless. Use of the destination database connection while a 7485** backup is in progress might also also cause a mutex deadlock. 7486** 7487** If running in [shared cache mode], the application must 7488** guarantee that the shared cache used by the destination database 7489** is not accessed while the backup is running. In practice this means 7490** that the application must guarantee that the disk file being 7491** backed up to is not accessed by any connection within the process, 7492** not just the specific connection that was passed to sqlite3_backup_init(). 7493** 7494** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7495** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7496** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7497** APIs are not strictly speaking threadsafe. If they are invoked at the 7498** same time as another thread is invoking sqlite3_backup_step() it is 7499** possible that they return invalid values. 7500*/ 7501sqlite3_backup *sqlite3_backup_init( 7502 sqlite3 *pDest, /* Destination database handle */ 7503 const char *zDestName, /* Destination database name */ 7504 sqlite3 *pSource, /* Source database handle */ 7505 const char *zSourceName /* Source database name */ 7506); 7507int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7508int sqlite3_backup_finish(sqlite3_backup *p); 7509int sqlite3_backup_remaining(sqlite3_backup *p); 7510int sqlite3_backup_pagecount(sqlite3_backup *p); 7511 7512/* 7513** CAPI3REF: Unlock Notification 7514** METHOD: sqlite3 7515** 7516** ^When running in shared-cache mode, a database operation may fail with 7517** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7518** individual tables within the shared-cache cannot be obtained. See 7519** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7520** ^This API may be used to register a callback that SQLite will invoke 7521** when the connection currently holding the required lock relinquishes it. 7522** ^This API is only available if the library was compiled with the 7523** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7524** 7525** See Also: [Using the SQLite Unlock Notification Feature]. 7526** 7527** ^Shared-cache locks are released when a database connection concludes 7528** its current transaction, either by committing it or rolling it back. 7529** 7530** ^When a connection (known as the blocked connection) fails to obtain a 7531** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7532** identity of the database connection (the blocking connection) that 7533** has locked the required resource is stored internally. ^After an 7534** application receives an SQLITE_LOCKED error, it may call the 7535** sqlite3_unlock_notify() method with the blocked connection handle as 7536** the first argument to register for a callback that will be invoked 7537** when the blocking connections current transaction is concluded. ^The 7538** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7539** call that concludes the blocking connections transaction. 7540** 7541** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7542** there is a chance that the blocking connection will have already 7543** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7544** If this happens, then the specified callback is invoked immediately, 7545** from within the call to sqlite3_unlock_notify().)^ 7546** 7547** ^If the blocked connection is attempting to obtain a write-lock on a 7548** shared-cache table, and more than one other connection currently holds 7549** a read-lock on the same table, then SQLite arbitrarily selects one of 7550** the other connections to use as the blocking connection. 7551** 7552** ^(There may be at most one unlock-notify callback registered by a 7553** blocked connection. If sqlite3_unlock_notify() is called when the 7554** blocked connection already has a registered unlock-notify callback, 7555** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7556** called with a NULL pointer as its second argument, then any existing 7557** unlock-notify callback is canceled. ^The blocked connections 7558** unlock-notify callback may also be canceled by closing the blocked 7559** connection using [sqlite3_close()]. 7560** 7561** The unlock-notify callback is not reentrant. If an application invokes 7562** any sqlite3_xxx API functions from within an unlock-notify callback, a 7563** crash or deadlock may be the result. 7564** 7565** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7566** returns SQLITE_OK. 7567** 7568** <b>Callback Invocation Details</b> 7569** 7570** When an unlock-notify callback is registered, the application provides a 7571** single void* pointer that is passed to the callback when it is invoked. 7572** However, the signature of the callback function allows SQLite to pass 7573** it an array of void* context pointers. The first argument passed to 7574** an unlock-notify callback is a pointer to an array of void* pointers, 7575** and the second is the number of entries in the array. 7576** 7577** When a blocking connections transaction is concluded, there may be 7578** more than one blocked connection that has registered for an unlock-notify 7579** callback. ^If two or more such blocked connections have specified the 7580** same callback function, then instead of invoking the callback function 7581** multiple times, it is invoked once with the set of void* context pointers 7582** specified by the blocked connections bundled together into an array. 7583** This gives the application an opportunity to prioritize any actions 7584** related to the set of unblocked database connections. 7585** 7586** <b>Deadlock Detection</b> 7587** 7588** Assuming that after registering for an unlock-notify callback a 7589** database waits for the callback to be issued before taking any further 7590** action (a reasonable assumption), then using this API may cause the 7591** application to deadlock. For example, if connection X is waiting for 7592** connection Y's transaction to be concluded, and similarly connection 7593** Y is waiting on connection X's transaction, then neither connection 7594** will proceed and the system may remain deadlocked indefinitely. 7595** 7596** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7597** detection. ^If a given call to sqlite3_unlock_notify() would put the 7598** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7599** unlock-notify callback is registered. The system is said to be in 7600** a deadlocked state if connection A has registered for an unlock-notify 7601** callback on the conclusion of connection B's transaction, and connection 7602** B has itself registered for an unlock-notify callback when connection 7603** A's transaction is concluded. ^Indirect deadlock is also detected, so 7604** the system is also considered to be deadlocked if connection B has 7605** registered for an unlock-notify callback on the conclusion of connection 7606** C's transaction, where connection C is waiting on connection A. ^Any 7607** number of levels of indirection are allowed. 7608** 7609** <b>The "DROP TABLE" Exception</b> 7610** 7611** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7612** always appropriate to call sqlite3_unlock_notify(). There is however, 7613** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7614** SQLite checks if there are any currently executing SELECT statements 7615** that belong to the same connection. If there are, SQLITE_LOCKED is 7616** returned. In this case there is no "blocking connection", so invoking 7617** sqlite3_unlock_notify() results in the unlock-notify callback being 7618** invoked immediately. If the application then re-attempts the "DROP TABLE" 7619** or "DROP INDEX" query, an infinite loop might be the result. 7620** 7621** One way around this problem is to check the extended error code returned 7622** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7623** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7624** the special "DROP TABLE/INDEX" case, the extended error code is just 7625** SQLITE_LOCKED.)^ 7626*/ 7627int sqlite3_unlock_notify( 7628 sqlite3 *pBlocked, /* Waiting connection */ 7629 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7630 void *pNotifyArg /* Argument to pass to xNotify */ 7631); 7632 7633 7634/* 7635** CAPI3REF: String Comparison 7636** 7637** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7638** and extensions to compare the contents of two buffers containing UTF-8 7639** strings in a case-independent fashion, using the same definition of "case 7640** independence" that SQLite uses internally when comparing identifiers. 7641*/ 7642int sqlite3_stricmp(const char *, const char *); 7643int sqlite3_strnicmp(const char *, const char *, int); 7644 7645/* 7646** CAPI3REF: String Globbing 7647* 7648** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7649** string X matches the [GLOB] pattern P. 7650** ^The definition of [GLOB] pattern matching used in 7651** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7652** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7653** is case sensitive. 7654** 7655** Note that this routine returns zero on a match and non-zero if the strings 7656** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7657** 7658** See also: [sqlite3_strlike()]. 7659*/ 7660int sqlite3_strglob(const char *zGlob, const char *zStr); 7661 7662/* 7663** CAPI3REF: String LIKE Matching 7664* 7665** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7666** string X matches the [LIKE] pattern P with escape character E. 7667** ^The definition of [LIKE] pattern matching used in 7668** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7669** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7670** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7671** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7672** insensitive - equivalent upper and lower case ASCII characters match 7673** one another. 7674** 7675** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7676** only ASCII characters are case folded. 7677** 7678** Note that this routine returns zero on a match and non-zero if the strings 7679** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7680** 7681** See also: [sqlite3_strglob()]. 7682*/ 7683int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7684 7685/* 7686** CAPI3REF: Error Logging Interface 7687** 7688** ^The [sqlite3_log()] interface writes a message into the [error log] 7689** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7690** ^If logging is enabled, the zFormat string and subsequent arguments are 7691** used with [sqlite3_snprintf()] to generate the final output string. 7692** 7693** The sqlite3_log() interface is intended for use by extensions such as 7694** virtual tables, collating functions, and SQL functions. While there is 7695** nothing to prevent an application from calling sqlite3_log(), doing so 7696** is considered bad form. 7697** 7698** The zFormat string must not be NULL. 7699** 7700** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7701** will not use dynamically allocated memory. The log message is stored in 7702** a fixed-length buffer on the stack. If the log message is longer than 7703** a few hundred characters, it will be truncated to the length of the 7704** buffer. 7705*/ 7706void sqlite3_log(int iErrCode, const char *zFormat, ...); 7707 7708/* 7709** CAPI3REF: Write-Ahead Log Commit Hook 7710** METHOD: sqlite3 7711** 7712** ^The [sqlite3_wal_hook()] function is used to register a callback that 7713** is invoked each time data is committed to a database in wal mode. 7714** 7715** ^(The callback is invoked by SQLite after the commit has taken place and 7716** the associated write-lock on the database released)^, so the implementation 7717** may read, write or [checkpoint] the database as required. 7718** 7719** ^The first parameter passed to the callback function when it is invoked 7720** is a copy of the third parameter passed to sqlite3_wal_hook() when 7721** registering the callback. ^The second is a copy of the database handle. 7722** ^The third parameter is the name of the database that was written to - 7723** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 7724** is the number of pages currently in the write-ahead log file, 7725** including those that were just committed. 7726** 7727** The callback function should normally return [SQLITE_OK]. ^If an error 7728** code is returned, that error will propagate back up through the 7729** SQLite code base to cause the statement that provoked the callback 7730** to report an error, though the commit will have still occurred. If the 7731** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 7732** that does not correspond to any valid SQLite error code, the results 7733** are undefined. 7734** 7735** A single database handle may have at most a single write-ahead log callback 7736** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 7737** previously registered write-ahead log callback. ^Note that the 7738** [sqlite3_wal_autocheckpoint()] interface and the 7739** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 7740** overwrite any prior [sqlite3_wal_hook()] settings. 7741*/ 7742void *sqlite3_wal_hook( 7743 sqlite3*, 7744 int(*)(void *,sqlite3*,const char*,int), 7745 void* 7746); 7747 7748/* 7749** CAPI3REF: Configure an auto-checkpoint 7750** METHOD: sqlite3 7751** 7752** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 7753** [sqlite3_wal_hook()] that causes any database on [database connection] D 7754** to automatically [checkpoint] 7755** after committing a transaction if there are N or 7756** more frames in the [write-ahead log] file. ^Passing zero or 7757** a negative value as the nFrame parameter disables automatic 7758** checkpoints entirely. 7759** 7760** ^The callback registered by this function replaces any existing callback 7761** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 7762** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 7763** configured by this function. 7764** 7765** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 7766** from SQL. 7767** 7768** ^Checkpoints initiated by this mechanism are 7769** [sqlite3_wal_checkpoint_v2|PASSIVE]. 7770** 7771** ^Every new [database connection] defaults to having the auto-checkpoint 7772** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 7773** pages. The use of this interface 7774** is only necessary if the default setting is found to be suboptimal 7775** for a particular application. 7776*/ 7777int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 7778 7779/* 7780** CAPI3REF: Checkpoint a database 7781** METHOD: sqlite3 7782** 7783** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 7784** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 7785** 7786** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 7787** [write-ahead log] for database X on [database connection] D to be 7788** transferred into the database file and for the write-ahead log to 7789** be reset. See the [checkpointing] documentation for addition 7790** information. 7791** 7792** This interface used to be the only way to cause a checkpoint to 7793** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 7794** interface was added. This interface is retained for backwards 7795** compatibility and as a convenience for applications that need to manually 7796** start a callback but which do not need the full power (and corresponding 7797** complication) of [sqlite3_wal_checkpoint_v2()]. 7798*/ 7799int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 7800 7801/* 7802** CAPI3REF: Checkpoint a database 7803** METHOD: sqlite3 7804** 7805** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 7806** operation on database X of [database connection] D in mode M. Status 7807** information is written back into integers pointed to by L and C.)^ 7808** ^(The M parameter must be a valid [checkpoint mode]:)^ 7809** 7810** <dl> 7811** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 7812** ^Checkpoint as many frames as possible without waiting for any database 7813** readers or writers to finish, then sync the database file if all frames 7814** in the log were checkpointed. ^The [busy-handler callback] 7815** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 7816** ^On the other hand, passive mode might leave the checkpoint unfinished 7817** if there are concurrent readers or writers. 7818** 7819** <dt>SQLITE_CHECKPOINT_FULL<dd> 7820** ^This mode blocks (it invokes the 7821** [sqlite3_busy_handler|busy-handler callback]) until there is no 7822** database writer and all readers are reading from the most recent database 7823** snapshot. ^It then checkpoints all frames in the log file and syncs the 7824** database file. ^This mode blocks new database writers while it is pending, 7825** but new database readers are allowed to continue unimpeded. 7826** 7827** <dt>SQLITE_CHECKPOINT_RESTART<dd> 7828** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 7829** that after checkpointing the log file it blocks (calls the 7830** [busy-handler callback]) 7831** until all readers are reading from the database file only. ^This ensures 7832** that the next writer will restart the log file from the beginning. 7833** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 7834** database writer attempts while it is pending, but does not impede readers. 7835** 7836** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 7837** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 7838** addition that it also truncates the log file to zero bytes just prior 7839** to a successful return. 7840** </dl> 7841** 7842** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 7843** the log file or to -1 if the checkpoint could not run because 7844** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 7845** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 7846** log file (including any that were already checkpointed before the function 7847** was called) or to -1 if the checkpoint could not run due to an error or 7848** because the database is not in WAL mode. ^Note that upon successful 7849** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 7850** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 7851** 7852** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 7853** any other process is running a checkpoint operation at the same time, the 7854** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 7855** busy-handler configured, it will not be invoked in this case. 7856** 7857** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 7858** exclusive "writer" lock on the database file. ^If the writer lock cannot be 7859** obtained immediately, and a busy-handler is configured, it is invoked and 7860** the writer lock retried until either the busy-handler returns 0 or the lock 7861** is successfully obtained. ^The busy-handler is also invoked while waiting for 7862** database readers as described above. ^If the busy-handler returns 0 before 7863** the writer lock is obtained or while waiting for database readers, the 7864** checkpoint operation proceeds from that point in the same way as 7865** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 7866** without blocking any further. ^SQLITE_BUSY is returned in this case. 7867** 7868** ^If parameter zDb is NULL or points to a zero length string, then the 7869** specified operation is attempted on all WAL databases [attached] to 7870** [database connection] db. In this case the 7871** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 7872** an SQLITE_BUSY error is encountered when processing one or more of the 7873** attached WAL databases, the operation is still attempted on any remaining 7874** attached databases and SQLITE_BUSY is returned at the end. ^If any other 7875** error occurs while processing an attached database, processing is abandoned 7876** and the error code is returned to the caller immediately. ^If no error 7877** (SQLITE_BUSY or otherwise) is encountered while processing the attached 7878** databases, SQLITE_OK is returned. 7879** 7880** ^If database zDb is the name of an attached database that is not in WAL 7881** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 7882** zDb is not NULL (or a zero length string) and is not the name of any 7883** attached database, SQLITE_ERROR is returned to the caller. 7884** 7885** ^Unless it returns SQLITE_MISUSE, 7886** the sqlite3_wal_checkpoint_v2() interface 7887** sets the error information that is queried by 7888** [sqlite3_errcode()] and [sqlite3_errmsg()]. 7889** 7890** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 7891** from SQL. 7892*/ 7893int sqlite3_wal_checkpoint_v2( 7894 sqlite3 *db, /* Database handle */ 7895 const char *zDb, /* Name of attached database (or NULL) */ 7896 int eMode, /* SQLITE_CHECKPOINT_* value */ 7897 int *pnLog, /* OUT: Size of WAL log in frames */ 7898 int *pnCkpt /* OUT: Total number of frames checkpointed */ 7899); 7900 7901/* 7902** CAPI3REF: Checkpoint Mode Values 7903** KEYWORDS: {checkpoint mode} 7904** 7905** These constants define all valid values for the "checkpoint mode" passed 7906** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 7907** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 7908** meaning of each of these checkpoint modes. 7909*/ 7910#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 7911#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 7912#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 7913#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 7914 7915/* 7916** CAPI3REF: Virtual Table Interface Configuration 7917** 7918** This function may be called by either the [xConnect] or [xCreate] method 7919** of a [virtual table] implementation to configure 7920** various facets of the virtual table interface. 7921** 7922** If this interface is invoked outside the context of an xConnect or 7923** xCreate virtual table method then the behavior is undefined. 7924** 7925** At present, there is only one option that may be configured using 7926** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 7927** may be added in the future. 7928*/ 7929int sqlite3_vtab_config(sqlite3*, int op, ...); 7930 7931/* 7932** CAPI3REF: Virtual Table Configuration Options 7933** 7934** These macros define the various options to the 7935** [sqlite3_vtab_config()] interface that [virtual table] implementations 7936** can use to customize and optimize their behavior. 7937** 7938** <dl> 7939** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 7940** <dd>Calls of the form 7941** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 7942** where X is an integer. If X is zero, then the [virtual table] whose 7943** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 7944** support constraints. In this configuration (which is the default) if 7945** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 7946** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 7947** specified as part of the users SQL statement, regardless of the actual 7948** ON CONFLICT mode specified. 7949** 7950** If X is non-zero, then the virtual table implementation guarantees 7951** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 7952** any modifications to internal or persistent data structures have been made. 7953** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 7954** is able to roll back a statement or database transaction, and abandon 7955** or continue processing the current SQL statement as appropriate. 7956** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 7957** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 7958** had been ABORT. 7959** 7960** Virtual table implementations that are required to handle OR REPLACE 7961** must do so within the [xUpdate] method. If a call to the 7962** [sqlite3_vtab_on_conflict()] function indicates that the current ON 7963** CONFLICT policy is REPLACE, the virtual table implementation should 7964** silently replace the appropriate rows within the xUpdate callback and 7965** return SQLITE_OK. Or, if this is not possible, it may return 7966** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 7967** constraint handling. 7968** </dl> 7969*/ 7970#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 7971 7972/* 7973** CAPI3REF: Determine The Virtual Table Conflict Policy 7974** 7975** This function may only be called from within a call to the [xUpdate] method 7976** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 7977** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 7978** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 7979** of the SQL statement that triggered the call to the [xUpdate] method of the 7980** [virtual table]. 7981*/ 7982int sqlite3_vtab_on_conflict(sqlite3 *); 7983 7984/* 7985** CAPI3REF: Conflict resolution modes 7986** KEYWORDS: {conflict resolution mode} 7987** 7988** These constants are returned by [sqlite3_vtab_on_conflict()] to 7989** inform a [virtual table] implementation what the [ON CONFLICT] mode 7990** is for the SQL statement being evaluated. 7991** 7992** Note that the [SQLITE_IGNORE] constant is also used as a potential 7993** return value from the [sqlite3_set_authorizer()] callback and that 7994** [SQLITE_ABORT] is also a [result code]. 7995*/ 7996#define SQLITE_ROLLBACK 1 7997/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 7998#define SQLITE_FAIL 3 7999/* #define SQLITE_ABORT 4 // Also an error code */ 8000#define SQLITE_REPLACE 5 8001 8002/* 8003** CAPI3REF: Prepared Statement Scan Status Opcodes 8004** KEYWORDS: {scanstatus options} 8005** 8006** The following constants can be used for the T parameter to the 8007** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8008** different metric for sqlite3_stmt_scanstatus() to return. 8009** 8010** When the value returned to V is a string, space to hold that string is 8011** managed by the prepared statement S and will be automatically freed when 8012** S is finalized. 8013** 8014** <dl> 8015** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8016** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8017** set to the total number of times that the X-th loop has run.</dd> 8018** 8019** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8020** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8021** to the total number of rows examined by all iterations of the X-th loop.</dd> 8022** 8023** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8024** <dd>^The "double" variable pointed to by the T parameter will be set to the 8025** query planner's estimate for the average number of rows output from each 8026** iteration of the X-th loop. If the query planner's estimates was accurate, 8027** then this value will approximate the quotient NVISIT/NLOOP and the 8028** product of this value for all prior loops with the same SELECTID will 8029** be the NLOOP value for the current loop. 8030** 8031** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8032** <dd>^The "const char *" variable pointed to by the T parameter will be set 8033** to a zero-terminated UTF-8 string containing the name of the index or table 8034** used for the X-th loop. 8035** 8036** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8037** <dd>^The "const char *" variable pointed to by the T parameter will be set 8038** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8039** description for the X-th loop. 8040** 8041** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8042** <dd>^The "int" variable pointed to by the T parameter will be set to the 8043** "select-id" for the X-th loop. The select-id identifies which query or 8044** subquery the loop is part of. The main query has a select-id of zero. 8045** The select-id is the same value as is output in the first column 8046** of an [EXPLAIN QUERY PLAN] query. 8047** </dl> 8048*/ 8049#define SQLITE_SCANSTAT_NLOOP 0 8050#define SQLITE_SCANSTAT_NVISIT 1 8051#define SQLITE_SCANSTAT_EST 2 8052#define SQLITE_SCANSTAT_NAME 3 8053#define SQLITE_SCANSTAT_EXPLAIN 4 8054#define SQLITE_SCANSTAT_SELECTID 5 8055 8056/* 8057** CAPI3REF: Prepared Statement Scan Status 8058** METHOD: sqlite3_stmt 8059** 8060** This interface returns information about the predicted and measured 8061** performance for pStmt. Advanced applications can use this 8062** interface to compare the predicted and the measured performance and 8063** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8064** 8065** Since this interface is expected to be rarely used, it is only 8066** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8067** compile-time option. 8068** 8069** The "iScanStatusOp" parameter determines which status information to return. 8070** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8071** of this interface is undefined. 8072** ^The requested measurement is written into a variable pointed to by 8073** the "pOut" parameter. 8074** Parameter "idx" identifies the specific loop to retrieve statistics for. 8075** Loops are numbered starting from zero. ^If idx is out of range - less than 8076** zero or greater than or equal to the total number of loops used to implement 8077** the statement - a non-zero value is returned and the variable that pOut 8078** points to is unchanged. 8079** 8080** ^Statistics might not be available for all loops in all statements. ^In cases 8081** where there exist loops with no available statistics, this function behaves 8082** as if the loop did not exist - it returns non-zero and leave the variable 8083** that pOut points to unchanged. 8084** 8085** See also: [sqlite3_stmt_scanstatus_reset()] 8086*/ 8087int sqlite3_stmt_scanstatus( 8088 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8089 int idx, /* Index of loop to report on */ 8090 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8091 void *pOut /* Result written here */ 8092); 8093 8094/* 8095** CAPI3REF: Zero Scan-Status Counters 8096** METHOD: sqlite3_stmt 8097** 8098** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8099** 8100** This API is only available if the library is built with pre-processor 8101** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8102*/ 8103void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8104 8105/* 8106** CAPI3REF: Flush caches to disk mid-transaction 8107** 8108** ^If a write-transaction is open on [database connection] D when the 8109** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8110** pages in the pager-cache that are not currently in use are written out 8111** to disk. A dirty page may be in use if a database cursor created by an 8112** active SQL statement is reading from it, or if it is page 1 of a database 8113** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8114** interface flushes caches for all schemas - "main", "temp", and 8115** any [attached] databases. 8116** 8117** ^If this function needs to obtain extra database locks before dirty pages 8118** can be flushed to disk, it does so. ^If those locks cannot be obtained 8119** immediately and there is a busy-handler callback configured, it is invoked 8120** in the usual manner. ^If the required lock still cannot be obtained, then 8121** the database is skipped and an attempt made to flush any dirty pages 8122** belonging to the next (if any) database. ^If any databases are skipped 8123** because locks cannot be obtained, but no other error occurs, this 8124** function returns SQLITE_BUSY. 8125** 8126** ^If any other error occurs while flushing dirty pages to disk (for 8127** example an IO error or out-of-memory condition), then processing is 8128** abandoned and an SQLite [error code] is returned to the caller immediately. 8129** 8130** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8131** 8132** ^This function does not set the database handle error code or message 8133** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8134*/ 8135int sqlite3_db_cacheflush(sqlite3*); 8136 8137/* 8138** CAPI3REF: The pre-update hook. 8139** 8140** ^These interfaces are only available if SQLite is compiled using the 8141** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8142** 8143** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8144** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8145** on a [rowid table]. 8146** ^At most one preupdate hook may be registered at a time on a single 8147** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8148** the previous setting. 8149** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8150** with a NULL pointer as the second parameter. 8151** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8152** the first parameter to callbacks. 8153** 8154** ^The preupdate hook only fires for changes to [rowid tables]; the preupdate 8155** hook is not invoked for changes to [virtual tables] or [WITHOUT ROWID] 8156** tables. 8157** 8158** ^The second parameter to the preupdate callback is a pointer to 8159** the [database connection] that registered the preupdate hook. 8160** ^The third parameter to the preupdate callback is one of the constants 8161** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8162** kind of update operation that is about to occur. 8163** ^(The fourth parameter to the preupdate callback is the name of the 8164** database within the database connection that is being modified. This 8165** will be "main" for the main database or "temp" for TEMP tables or 8166** the name given after the AS keyword in the [ATTACH] statement for attached 8167** databases.)^ 8168** ^The fifth parameter to the preupdate callback is the name of the 8169** table that is being modified. 8170** ^The sixth parameter to the preupdate callback is the initial [rowid] of the 8171** row being changes for SQLITE_UPDATE and SQLITE_DELETE changes and is 8172** undefined for SQLITE_INSERT changes. 8173** ^The seventh parameter to the preupdate callback is the final [rowid] of 8174** the row being changed for SQLITE_UPDATE and SQLITE_INSERT changes and is 8175** undefined for SQLITE_DELETE changes. 8176** 8177** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8178** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8179** provide additional information about a preupdate event. These routines 8180** may only be called from within a preupdate callback. Invoking any of 8181** these routines from outside of a preupdate callback or with a 8182** [database connection] pointer that is different from the one supplied 8183** to the preupdate callback results in undefined and probably undesirable 8184** behavior. 8185** 8186** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8187** in the row that is being inserted, updated, or deleted. 8188** 8189** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8190** a [protected sqlite3_value] that contains the value of the Nth column of 8191** the table row before it is updated. The N parameter must be between 0 8192** and one less than the number of columns or the behavior will be 8193** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8194** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8195** behavior is undefined. The [sqlite3_value] that P points to 8196** will be destroyed when the preupdate callback returns. 8197** 8198** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8199** a [protected sqlite3_value] that contains the value of the Nth column of 8200** the table row after it is updated. The N parameter must be between 0 8201** and one less than the number of columns or the behavior will be 8202** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8203** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8204** behavior is undefined. The [sqlite3_value] that P points to 8205** will be destroyed when the preupdate callback returns. 8206** 8207** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8208** callback was invoked as a result of a direct insert, update, or delete 8209** operation; or 1 for inserts, updates, or deletes invoked by top-level 8210** triggers; or 2 for changes resulting from triggers called by top-level 8211** triggers; and so forth. 8212** 8213** See also: [sqlite3_update_hook()] 8214*/ 8215SQLITE_EXPERIMENTAL void *sqlite3_preupdate_hook( 8216 sqlite3 *db, 8217 void(*xPreUpdate)( 8218 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8219 sqlite3 *db, /* Database handle */ 8220 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8221 char const *zDb, /* Database name */ 8222 char const *zName, /* Table name */ 8223 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8224 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8225 ), 8226 void* 8227); 8228SQLITE_EXPERIMENTAL int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8229SQLITE_EXPERIMENTAL int sqlite3_preupdate_count(sqlite3 *); 8230SQLITE_EXPERIMENTAL int sqlite3_preupdate_depth(sqlite3 *); 8231SQLITE_EXPERIMENTAL int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8232 8233/* 8234** CAPI3REF: Low-level system error code 8235** 8236** ^Attempt to return the underlying operating system error code or error 8237** number that caused the most recent I/O error or failure to open a file. 8238** The return value is OS-dependent. For example, on unix systems, after 8239** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8240** called to get back the underlying "errno" that caused the problem, such 8241** as ENOSPC, EAUTH, EISDIR, and so forth. 8242*/ 8243int sqlite3_system_errno(sqlite3*); 8244 8245/* 8246** CAPI3REF: Database Snapshot 8247** KEYWORDS: {snapshot} 8248** EXPERIMENTAL 8249** 8250** An instance of the snapshot object records the state of a [WAL mode] 8251** database for some specific point in history. 8252** 8253** In [WAL mode], multiple [database connections] that are open on the 8254** same database file can each be reading a different historical version 8255** of the database file. When a [database connection] begins a read 8256** transaction, that connection sees an unchanging copy of the database 8257** as it existed for the point in time when the transaction first started. 8258** Subsequent changes to the database from other connections are not seen 8259** by the reader until a new read transaction is started. 8260** 8261** The sqlite3_snapshot object records state information about an historical 8262** version of the database file so that it is possible to later open a new read 8263** transaction that sees that historical version of the database rather than 8264** the most recent version. 8265** 8266** The constructor for this object is [sqlite3_snapshot_get()]. The 8267** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8268** to an historical snapshot (if possible). The destructor for 8269** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8270*/ 8271typedef struct sqlite3_snapshot sqlite3_snapshot; 8272 8273/* 8274** CAPI3REF: Record A Database Snapshot 8275** EXPERIMENTAL 8276** 8277** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8278** new [sqlite3_snapshot] object that records the current state of 8279** schema S in database connection D. ^On success, the 8280** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8281** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8282** ^If schema S of [database connection] D is not a [WAL mode] database 8283** that is in a read transaction, then [sqlite3_snapshot_get(D,S,P)] 8284** leaves the *P value unchanged and returns an appropriate [error code]. 8285** 8286** The [sqlite3_snapshot] object returned from a successful call to 8287** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8288** to avoid a memory leak. 8289** 8290** The [sqlite3_snapshot_get()] interface is only available when the 8291** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8292*/ 8293SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8294 sqlite3 *db, 8295 const char *zSchema, 8296 sqlite3_snapshot **ppSnapshot 8297); 8298 8299/* 8300** CAPI3REF: Start a read transaction on an historical snapshot 8301** EXPERIMENTAL 8302** 8303** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8304** read transaction for schema S of 8305** [database connection] D such that the read transaction 8306** refers to historical [snapshot] P, rather than the most 8307** recent change to the database. 8308** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8309** or an appropriate [error code] if it fails. 8310** 8311** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8312** the first operation following the [BEGIN] that takes the schema S 8313** out of [autocommit mode]. 8314** ^In other words, schema S must not currently be in 8315** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8316** database connection D must be out of [autocommit mode]. 8317** ^A [snapshot] will fail to open if it has been overwritten by a 8318** [checkpoint]. 8319** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8320** database connection D does not know that the database file for 8321** schema S is in [WAL mode]. A database connection might not know 8322** that the database file is in [WAL mode] if there has been no prior 8323** I/O on that database connection, or if the database entered [WAL mode] 8324** after the most recent I/O on the database connection.)^ 8325** (Hint: Run "[PRAGMA application_id]" against a newly opened 8326** database connection in order to make it ready to use snapshots.) 8327** 8328** The [sqlite3_snapshot_open()] interface is only available when the 8329** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8330*/ 8331SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8332 sqlite3 *db, 8333 const char *zSchema, 8334 sqlite3_snapshot *pSnapshot 8335); 8336 8337/* 8338** CAPI3REF: Destroy a snapshot 8339** EXPERIMENTAL 8340** 8341** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8342** The application must eventually free every [sqlite3_snapshot] object 8343** using this routine to avoid a memory leak. 8344** 8345** The [sqlite3_snapshot_free()] interface is only available when the 8346** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8347*/ 8348SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8349 8350/* 8351** CAPI3REF: Compare the ages of two snapshot handles. 8352** EXPERIMENTAL 8353** 8354** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8355** of two valid snapshot handles. 8356** 8357** If the two snapshot handles are not associated with the same database 8358** file, the result of the comparison is undefined. 8359** 8360** Additionally, the result of the comparison is only valid if both of the 8361** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8362** last time the wal file was deleted. The wal file is deleted when the 8363** database is changed back to rollback mode or when the number of database 8364** clients drops to zero. If either snapshot handle was obtained before the 8365** wal file was last deleted, the value returned by this function 8366** is undefined. 8367** 8368** Otherwise, this API returns a negative value if P1 refers to an older 8369** snapshot than P2, zero if the two handles refer to the same database 8370** snapshot, and a positive value if P1 is a newer snapshot than P2. 8371*/ 8372SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8373 sqlite3_snapshot *p1, 8374 sqlite3_snapshot *p2 8375); 8376 8377/* 8378** Undo the hack that converts floating point types to integer for 8379** builds on processors without floating point support. 8380*/ 8381#ifdef SQLITE_OMIT_FLOATING_POINT 8382# undef double 8383#endif 8384 8385#ifdef __cplusplus 8386} /* End of the 'extern "C"' block */ 8387#endif 8388#endif /* SQLITE3_H */ 8389