1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#endif 193 194/* 195** CAPI3REF: Test To See If The Library Is Threadsafe 196** 197** ^The sqlite3_threadsafe() function returns zero if and only if 198** SQLite was compiled with mutexing code omitted due to the 199** [SQLITE_THREADSAFE] compile-time option being set to 0. 200** 201** SQLite can be compiled with or without mutexes. When 202** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 203** are enabled and SQLite is threadsafe. When the 204** [SQLITE_THREADSAFE] macro is 0, 205** the mutexes are omitted. Without the mutexes, it is not safe 206** to use SQLite concurrently from more than one thread. 207** 208** Enabling mutexes incurs a measurable performance penalty. 209** So if speed is of utmost importance, it makes sense to disable 210** the mutexes. But for maximum safety, mutexes should be enabled. 211** ^The default behavior is for mutexes to be enabled. 212** 213** This interface can be used by an application to make sure that the 214** version of SQLite that it is linking against was compiled with 215** the desired setting of the [SQLITE_THREADSAFE] macro. 216** 217** This interface only reports on the compile-time mutex setting 218** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 219** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 220** can be fully or partially disabled using a call to [sqlite3_config()] 221** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 222** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 223** sqlite3_threadsafe() function shows only the compile-time setting of 224** thread safety, not any run-time changes to that setting made by 225** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 226** is unchanged by calls to sqlite3_config().)^ 227** 228** See the [threading mode] documentation for additional information. 229*/ 230int sqlite3_threadsafe(void); 231 232/* 233** CAPI3REF: Database Connection Handle 234** KEYWORDS: {database connection} {database connections} 235** 236** Each open SQLite database is represented by a pointer to an instance of 237** the opaque structure named "sqlite3". It is useful to think of an sqlite3 238** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 239** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 240** and [sqlite3_close_v2()] are its destructors. There are many other 241** interfaces (such as 242** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 243** [sqlite3_busy_timeout()] to name but three) that are methods on an 244** sqlite3 object. 245*/ 246typedef struct sqlite3 sqlite3; 247 248/* 249** CAPI3REF: 64-Bit Integer Types 250** KEYWORDS: sqlite_int64 sqlite_uint64 251** 252** Because there is no cross-platform way to specify 64-bit integer types 253** SQLite includes typedefs for 64-bit signed and unsigned integers. 254** 255** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 256** The sqlite_int64 and sqlite_uint64 types are supported for backwards 257** compatibility only. 258** 259** ^The sqlite3_int64 and sqlite_int64 types can store integer values 260** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 261** sqlite3_uint64 and sqlite_uint64 types can store integer values 262** between 0 and +18446744073709551615 inclusive. 263*/ 264#ifdef SQLITE_INT64_TYPE 265 typedef SQLITE_INT64_TYPE sqlite_int64; 266# ifdef SQLITE_UINT64_TYPE 267 typedef SQLITE_UINT64_TYPE sqlite_uint64; 268# else 269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 270# endif 271#elif defined(_MSC_VER) || defined(__BORLANDC__) 272 typedef __int64 sqlite_int64; 273 typedef unsigned __int64 sqlite_uint64; 274#else 275 typedef long long int sqlite_int64; 276 typedef unsigned long long int sqlite_uint64; 277#endif 278typedef sqlite_int64 sqlite3_int64; 279typedef sqlite_uint64 sqlite3_uint64; 280 281/* 282** If compiling for a processor that lacks floating point support, 283** substitute integer for floating-point. 284*/ 285#ifdef SQLITE_OMIT_FLOATING_POINT 286# define double sqlite3_int64 287#endif 288 289/* 290** CAPI3REF: Closing A Database Connection 291** DESTRUCTOR: sqlite3 292** 293** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 294** for the [sqlite3] object. 295** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 296** the [sqlite3] object is successfully destroyed and all associated 297** resources are deallocated. 298** 299** ^If the database connection is associated with unfinalized prepared 300** statements or unfinished sqlite3_backup objects then sqlite3_close() 301** will leave the database connection open and return [SQLITE_BUSY]. 302** ^If sqlite3_close_v2() is called with unfinalized prepared statements 303** and/or unfinished sqlite3_backups, then the database connection becomes 304** an unusable "zombie" which will automatically be deallocated when the 305** last prepared statement is finalized or the last sqlite3_backup is 306** finished. The sqlite3_close_v2() interface is intended for use with 307** host languages that are garbage collected, and where the order in which 308** destructors are called is arbitrary. 309** 310** Applications should [sqlite3_finalize | finalize] all [prepared statements], 311** [sqlite3_blob_close | close] all [BLOB handles], and 312** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 313** with the [sqlite3] object prior to attempting to close the object. ^If 314** sqlite3_close_v2() is called on a [database connection] that still has 315** outstanding [prepared statements], [BLOB handles], and/or 316** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 317** of resources is deferred until all [prepared statements], [BLOB handles], 318** and [sqlite3_backup] objects are also destroyed. 319** 320** ^If an [sqlite3] object is destroyed while a transaction is open, 321** the transaction is automatically rolled back. 322** 323** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 324** must be either a NULL 325** pointer or an [sqlite3] object pointer obtained 326** from [sqlite3_open()], [sqlite3_open16()], or 327** [sqlite3_open_v2()], and not previously closed. 328** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 329** argument is a harmless no-op. 330*/ 331int sqlite3_close(sqlite3*); 332int sqlite3_close_v2(sqlite3*); 333 334/* 335** The type for a callback function. 336** This is legacy and deprecated. It is included for historical 337** compatibility and is not documented. 338*/ 339typedef int (*sqlite3_callback)(void*,int,char**, char**); 340 341/* 342** CAPI3REF: One-Step Query Execution Interface 343** METHOD: sqlite3 344** 345** The sqlite3_exec() interface is a convenience wrapper around 346** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 347** that allows an application to run multiple statements of SQL 348** without having to use a lot of C code. 349** 350** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 351** semicolon-separate SQL statements passed into its 2nd argument, 352** in the context of the [database connection] passed in as its 1st 353** argument. ^If the callback function of the 3rd argument to 354** sqlite3_exec() is not NULL, then it is invoked for each result row 355** coming out of the evaluated SQL statements. ^The 4th argument to 356** sqlite3_exec() is relayed through to the 1st argument of each 357** callback invocation. ^If the callback pointer to sqlite3_exec() 358** is NULL, then no callback is ever invoked and result rows are 359** ignored. 360** 361** ^If an error occurs while evaluating the SQL statements passed into 362** sqlite3_exec(), then execution of the current statement stops and 363** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 364** is not NULL then any error message is written into memory obtained 365** from [sqlite3_malloc()] and passed back through the 5th parameter. 366** To avoid memory leaks, the application should invoke [sqlite3_free()] 367** on error message strings returned through the 5th parameter of 368** sqlite3_exec() after the error message string is no longer needed. 369** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 370** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 371** NULL before returning. 372** 373** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 374** routine returns SQLITE_ABORT without invoking the callback again and 375** without running any subsequent SQL statements. 376** 377** ^The 2nd argument to the sqlite3_exec() callback function is the 378** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 379** callback is an array of pointers to strings obtained as if from 380** [sqlite3_column_text()], one for each column. ^If an element of a 381** result row is NULL then the corresponding string pointer for the 382** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 383** sqlite3_exec() callback is an array of pointers to strings where each 384** entry represents the name of corresponding result column as obtained 385** from [sqlite3_column_name()]. 386** 387** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 388** to an empty string, or a pointer that contains only whitespace and/or 389** SQL comments, then no SQL statements are evaluated and the database 390** is not changed. 391** 392** Restrictions: 393** 394** <ul> 395** <li> The application must ensure that the 1st parameter to sqlite3_exec() 396** is a valid and open [database connection]. 397** <li> The application must not close the [database connection] specified by 398** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 399** <li> The application must not modify the SQL statement text passed into 400** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 401** </ul> 402*/ 403int sqlite3_exec( 404 sqlite3*, /* An open database */ 405 const char *sql, /* SQL to be evaluated */ 406 int (*callback)(void*,int,char**,char**), /* Callback function */ 407 void *, /* 1st argument to callback */ 408 char **errmsg /* Error msg written here */ 409); 410 411/* 412** CAPI3REF: Result Codes 413** KEYWORDS: {result code definitions} 414** 415** Many SQLite functions return an integer result code from the set shown 416** here in order to indicate success or failure. 417** 418** New error codes may be added in future versions of SQLite. 419** 420** See also: [extended result code definitions] 421*/ 422#define SQLITE_OK 0 /* Successful result */ 423/* beginning-of-error-codes */ 424#define SQLITE_ERROR 1 /* Generic error */ 425#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 426#define SQLITE_PERM 3 /* Access permission denied */ 427#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 428#define SQLITE_BUSY 5 /* The database file is locked */ 429#define SQLITE_LOCKED 6 /* A table in the database is locked */ 430#define SQLITE_NOMEM 7 /* A malloc() failed */ 431#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 432#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 433#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 434#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 435#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 436#define SQLITE_FULL 13 /* Insertion failed because database is full */ 437#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 438#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 439#define SQLITE_EMPTY 16 /* Internal use only */ 440#define SQLITE_SCHEMA 17 /* The database schema changed */ 441#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 442#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 443#define SQLITE_MISMATCH 20 /* Data type mismatch */ 444#define SQLITE_MISUSE 21 /* Library used incorrectly */ 445#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 446#define SQLITE_AUTH 23 /* Authorization denied */ 447#define SQLITE_FORMAT 24 /* Not used */ 448#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 449#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 450#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 451#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 452#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 453#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 454/* end-of-error-codes */ 455 456/* 457** CAPI3REF: Extended Result Codes 458** KEYWORDS: {extended result code definitions} 459** 460** In its default configuration, SQLite API routines return one of 30 integer 461** [result codes]. However, experience has shown that many of 462** these result codes are too coarse-grained. They do not provide as 463** much information about problems as programmers might like. In an effort to 464** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 465** and later) include 466** support for additional result codes that provide more detailed information 467** about errors. These [extended result codes] are enabled or disabled 468** on a per database connection basis using the 469** [sqlite3_extended_result_codes()] API. Or, the extended code for 470** the most recent error can be obtained using 471** [sqlite3_extended_errcode()]. 472*/ 473#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 474#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 475#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 476#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 477#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 478#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 479#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 480#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 481#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 482#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 483#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 484#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 485#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 486#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 487#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 488#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 489#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 490#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 491#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 492#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 493#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 494#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 495#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 496#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 497#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 498#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 499#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 500#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 501#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 502#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 503#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 504#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 505#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 506#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 507#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 508#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 509#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 510#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 511#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 512#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 513#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 514#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 515#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 516#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 517#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 518#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 519#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 520#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 521#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 522#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 523#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 524#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 525#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 526#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 527#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 528#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 529#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 530#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 531#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 532 533/* 534** CAPI3REF: Flags For File Open Operations 535** 536** These bit values are intended for use in the 537** 3rd parameter to the [sqlite3_open_v2()] interface and 538** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 539*/ 540#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 541#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 542#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 543#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 544#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 545#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 546#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 547#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 548#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 549#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 550#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 551#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 552#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 553#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 554#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 555#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 557#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 558#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 559#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 560 561/* Reserved: 0x00F00000 */ 562 563/* 564** CAPI3REF: Device Characteristics 565** 566** The xDeviceCharacteristics method of the [sqlite3_io_methods] 567** object returns an integer which is a vector of these 568** bit values expressing I/O characteristics of the mass storage 569** device that holds the file that the [sqlite3_io_methods] 570** refers to. 571** 572** The SQLITE_IOCAP_ATOMIC property means that all writes of 573** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 574** mean that writes of blocks that are nnn bytes in size and 575** are aligned to an address which is an integer multiple of 576** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 577** that when data is appended to a file, the data is appended 578** first then the size of the file is extended, never the other 579** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 580** information is written to disk in the same order as calls 581** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 582** after reboot following a crash or power loss, the only bytes in a 583** file that were written at the application level might have changed 584** and that adjacent bytes, even bytes within the same sector are 585** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 586** flag indicates that a file cannot be deleted when open. The 587** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 588** read-only media and cannot be changed even by processes with 589** elevated privileges. 590** 591** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 592** filesystem supports doing multiple write operations atomically when those 593** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 594** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 595*/ 596#define SQLITE_IOCAP_ATOMIC 0x00000001 597#define SQLITE_IOCAP_ATOMIC512 0x00000002 598#define SQLITE_IOCAP_ATOMIC1K 0x00000004 599#define SQLITE_IOCAP_ATOMIC2K 0x00000008 600#define SQLITE_IOCAP_ATOMIC4K 0x00000010 601#define SQLITE_IOCAP_ATOMIC8K 0x00000020 602#define SQLITE_IOCAP_ATOMIC16K 0x00000040 603#define SQLITE_IOCAP_ATOMIC32K 0x00000080 604#define SQLITE_IOCAP_ATOMIC64K 0x00000100 605#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 606#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 607#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 608#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 609#define SQLITE_IOCAP_IMMUTABLE 0x00002000 610#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 611 612/* 613** CAPI3REF: File Locking Levels 614** 615** SQLite uses one of these integer values as the second 616** argument to calls it makes to the xLock() and xUnlock() methods 617** of an [sqlite3_io_methods] object. 618*/ 619#define SQLITE_LOCK_NONE 0 620#define SQLITE_LOCK_SHARED 1 621#define SQLITE_LOCK_RESERVED 2 622#define SQLITE_LOCK_PENDING 3 623#define SQLITE_LOCK_EXCLUSIVE 4 624 625/* 626** CAPI3REF: Synchronization Type Flags 627** 628** When SQLite invokes the xSync() method of an 629** [sqlite3_io_methods] object it uses a combination of 630** these integer values as the second argument. 631** 632** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 633** sync operation only needs to flush data to mass storage. Inode 634** information need not be flushed. If the lower four bits of the flag 635** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 636** If the lower four bits equal SQLITE_SYNC_FULL, that means 637** to use Mac OS X style fullsync instead of fsync(). 638** 639** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 640** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 641** settings. The [synchronous pragma] determines when calls to the 642** xSync VFS method occur and applies uniformly across all platforms. 643** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 644** energetic or rigorous or forceful the sync operations are and 645** only make a difference on Mac OSX for the default SQLite code. 646** (Third-party VFS implementations might also make the distinction 647** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 648** operating systems natively supported by SQLite, only Mac OSX 649** cares about the difference.) 650*/ 651#define SQLITE_SYNC_NORMAL 0x00002 652#define SQLITE_SYNC_FULL 0x00003 653#define SQLITE_SYNC_DATAONLY 0x00010 654 655/* 656** CAPI3REF: OS Interface Open File Handle 657** 658** An [sqlite3_file] object represents an open file in the 659** [sqlite3_vfs | OS interface layer]. Individual OS interface 660** implementations will 661** want to subclass this object by appending additional fields 662** for their own use. The pMethods entry is a pointer to an 663** [sqlite3_io_methods] object that defines methods for performing 664** I/O operations on the open file. 665*/ 666typedef struct sqlite3_file sqlite3_file; 667struct sqlite3_file { 668 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 669}; 670 671/* 672** CAPI3REF: OS Interface File Virtual Methods Object 673** 674** Every file opened by the [sqlite3_vfs.xOpen] method populates an 675** [sqlite3_file] object (or, more commonly, a subclass of the 676** [sqlite3_file] object) with a pointer to an instance of this object. 677** This object defines the methods used to perform various operations 678** against the open file represented by the [sqlite3_file] object. 679** 680** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 681** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 682** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 683** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 684** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 685** to NULL. 686** 687** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 688** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 689** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 690** flag may be ORed in to indicate that only the data of the file 691** and not its inode needs to be synced. 692** 693** The integer values to xLock() and xUnlock() are one of 694** <ul> 695** <li> [SQLITE_LOCK_NONE], 696** <li> [SQLITE_LOCK_SHARED], 697** <li> [SQLITE_LOCK_RESERVED], 698** <li> [SQLITE_LOCK_PENDING], or 699** <li> [SQLITE_LOCK_EXCLUSIVE]. 700** </ul> 701** xLock() increases the lock. xUnlock() decreases the lock. 702** The xCheckReservedLock() method checks whether any database connection, 703** either in this process or in some other process, is holding a RESERVED, 704** PENDING, or EXCLUSIVE lock on the file. It returns true 705** if such a lock exists and false otherwise. 706** 707** The xFileControl() method is a generic interface that allows custom 708** VFS implementations to directly control an open file using the 709** [sqlite3_file_control()] interface. The second "op" argument is an 710** integer opcode. The third argument is a generic pointer intended to 711** point to a structure that may contain arguments or space in which to 712** write return values. Potential uses for xFileControl() might be 713** functions to enable blocking locks with timeouts, to change the 714** locking strategy (for example to use dot-file locks), to inquire 715** about the status of a lock, or to break stale locks. The SQLite 716** core reserves all opcodes less than 100 for its own use. 717** A [file control opcodes | list of opcodes] less than 100 is available. 718** Applications that define a custom xFileControl method should use opcodes 719** greater than 100 to avoid conflicts. VFS implementations should 720** return [SQLITE_NOTFOUND] for file control opcodes that they do not 721** recognize. 722** 723** The xSectorSize() method returns the sector size of the 724** device that underlies the file. The sector size is the 725** minimum write that can be performed without disturbing 726** other bytes in the file. The xDeviceCharacteristics() 727** method returns a bit vector describing behaviors of the 728** underlying device: 729** 730** <ul> 731** <li> [SQLITE_IOCAP_ATOMIC] 732** <li> [SQLITE_IOCAP_ATOMIC512] 733** <li> [SQLITE_IOCAP_ATOMIC1K] 734** <li> [SQLITE_IOCAP_ATOMIC2K] 735** <li> [SQLITE_IOCAP_ATOMIC4K] 736** <li> [SQLITE_IOCAP_ATOMIC8K] 737** <li> [SQLITE_IOCAP_ATOMIC16K] 738** <li> [SQLITE_IOCAP_ATOMIC32K] 739** <li> [SQLITE_IOCAP_ATOMIC64K] 740** <li> [SQLITE_IOCAP_SAFE_APPEND] 741** <li> [SQLITE_IOCAP_SEQUENTIAL] 742** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 743** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 744** <li> [SQLITE_IOCAP_IMMUTABLE] 745** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 746** </ul> 747** 748** The SQLITE_IOCAP_ATOMIC property means that all writes of 749** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 750** mean that writes of blocks that are nnn bytes in size and 751** are aligned to an address which is an integer multiple of 752** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 753** that when data is appended to a file, the data is appended 754** first then the size of the file is extended, never the other 755** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 756** information is written to disk in the same order as calls 757** to xWrite(). 758** 759** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 760** in the unread portions of the buffer with zeros. A VFS that 761** fails to zero-fill short reads might seem to work. However, 762** failure to zero-fill short reads will eventually lead to 763** database corruption. 764*/ 765typedef struct sqlite3_io_methods sqlite3_io_methods; 766struct sqlite3_io_methods { 767 int iVersion; 768 int (*xClose)(sqlite3_file*); 769 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 770 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 771 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 772 int (*xSync)(sqlite3_file*, int flags); 773 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 774 int (*xLock)(sqlite3_file*, int); 775 int (*xUnlock)(sqlite3_file*, int); 776 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 777 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 778 int (*xSectorSize)(sqlite3_file*); 779 int (*xDeviceCharacteristics)(sqlite3_file*); 780 /* Methods above are valid for version 1 */ 781 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 782 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 783 void (*xShmBarrier)(sqlite3_file*); 784 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 785 /* Methods above are valid for version 2 */ 786 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 787 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 788 /* Methods above are valid for version 3 */ 789 /* Additional methods may be added in future releases */ 790}; 791 792/* 793** CAPI3REF: Standard File Control Opcodes 794** KEYWORDS: {file control opcodes} {file control opcode} 795** 796** These integer constants are opcodes for the xFileControl method 797** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 798** interface. 799** 800** <ul> 801** <li>[[SQLITE_FCNTL_LOCKSTATE]] 802** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 803** opcode causes the xFileControl method to write the current state of 804** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 805** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 806** into an integer that the pArg argument points to. This capability 807** is used during testing and is only available when the SQLITE_TEST 808** compile-time option is used. 809** 810** <li>[[SQLITE_FCNTL_SIZE_HINT]] 811** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 812** layer a hint of how large the database file will grow to be during the 813** current transaction. This hint is not guaranteed to be accurate but it 814** is often close. The underlying VFS might choose to preallocate database 815** file space based on this hint in order to help writes to the database 816** file run faster. 817** 818** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 819** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 820** extends and truncates the database file in chunks of a size specified 821** by the user. The fourth argument to [sqlite3_file_control()] should 822** point to an integer (type int) containing the new chunk-size to use 823** for the nominated database. Allocating database file space in large 824** chunks (say 1MB at a time), may reduce file-system fragmentation and 825** improve performance on some systems. 826** 827** <li>[[SQLITE_FCNTL_FILE_POINTER]] 828** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 829** to the [sqlite3_file] object associated with a particular database 830** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 831** 832** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 833** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 834** to the [sqlite3_file] object associated with the journal file (either 835** the [rollback journal] or the [write-ahead log]) for a particular database 836** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 837** 838** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 839** No longer in use. 840** 841** <li>[[SQLITE_FCNTL_SYNC]] 842** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 843** sent to the VFS immediately before the xSync method is invoked on a 844** database file descriptor. Or, if the xSync method is not invoked 845** because the user has configured SQLite with 846** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 847** of the xSync method. In most cases, the pointer argument passed with 848** this file-control is NULL. However, if the database file is being synced 849** as part of a multi-database commit, the argument points to a nul-terminated 850** string containing the transactions master-journal file name. VFSes that 851** do not need this signal should silently ignore this opcode. Applications 852** should not call [sqlite3_file_control()] with this opcode as doing so may 853** disrupt the operation of the specialized VFSes that do require it. 854** 855** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 856** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 857** and sent to the VFS after a transaction has been committed immediately 858** but before the database is unlocked. VFSes that do not need this signal 859** should silently ignore this opcode. Applications should not call 860** [sqlite3_file_control()] with this opcode as doing so may disrupt the 861** operation of the specialized VFSes that do require it. 862** 863** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 864** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 865** retry counts and intervals for certain disk I/O operations for the 866** windows [VFS] in order to provide robustness in the presence of 867** anti-virus programs. By default, the windows VFS will retry file read, 868** file write, and file delete operations up to 10 times, with a delay 869** of 25 milliseconds before the first retry and with the delay increasing 870** by an additional 25 milliseconds with each subsequent retry. This 871** opcode allows these two values (10 retries and 25 milliseconds of delay) 872** to be adjusted. The values are changed for all database connections 873** within the same process. The argument is a pointer to an array of two 874** integers where the first integer is the new retry count and the second 875** integer is the delay. If either integer is negative, then the setting 876** is not changed but instead the prior value of that setting is written 877** into the array entry, allowing the current retry settings to be 878** interrogated. The zDbName parameter is ignored. 879** 880** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 881** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 882** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 883** write ahead log and shared memory files used for transaction control 884** are automatically deleted when the latest connection to the database 885** closes. Setting persistent WAL mode causes those files to persist after 886** close. Persisting the files is useful when other processes that do not 887** have write permission on the directory containing the database file want 888** to read the database file, as the WAL and shared memory files must exist 889** in order for the database to be readable. The fourth parameter to 890** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 891** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 892** WAL mode. If the integer is -1, then it is overwritten with the current 893** WAL persistence setting. 894** 895** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 896** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 897** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 898** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 899** xDeviceCharacteristics methods. The fourth parameter to 900** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 901** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 902** mode. If the integer is -1, then it is overwritten with the current 903** zero-damage mode setting. 904** 905** <li>[[SQLITE_FCNTL_OVERWRITE]] 906** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 907** a write transaction to indicate that, unless it is rolled back for some 908** reason, the entire database file will be overwritten by the current 909** transaction. This is used by VACUUM operations. 910** 911** <li>[[SQLITE_FCNTL_VFSNAME]] 912** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 913** all [VFSes] in the VFS stack. The names are of all VFS shims and the 914** final bottom-level VFS are written into memory obtained from 915** [sqlite3_malloc()] and the result is stored in the char* variable 916** that the fourth parameter of [sqlite3_file_control()] points to. 917** The caller is responsible for freeing the memory when done. As with 918** all file-control actions, there is no guarantee that this will actually 919** do anything. Callers should initialize the char* variable to a NULL 920** pointer in case this file-control is not implemented. This file-control 921** is intended for diagnostic use only. 922** 923** <li>[[SQLITE_FCNTL_VFS_POINTER]] 924** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 925** [VFSes] currently in use. ^(The argument X in 926** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 927** of type "[sqlite3_vfs] **". This opcodes will set *X 928** to a pointer to the top-level VFS.)^ 929** ^When there are multiple VFS shims in the stack, this opcode finds the 930** upper-most shim only. 931** 932** <li>[[SQLITE_FCNTL_PRAGMA]] 933** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 934** file control is sent to the open [sqlite3_file] object corresponding 935** to the database file to which the pragma statement refers. ^The argument 936** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 937** pointers to strings (char**) in which the second element of the array 938** is the name of the pragma and the third element is the argument to the 939** pragma or NULL if the pragma has no argument. ^The handler for an 940** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 941** of the char** argument point to a string obtained from [sqlite3_mprintf()] 942** or the equivalent and that string will become the result of the pragma or 943** the error message if the pragma fails. ^If the 944** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 945** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 946** file control returns [SQLITE_OK], then the parser assumes that the 947** VFS has handled the PRAGMA itself and the parser generates a no-op 948** prepared statement if result string is NULL, or that returns a copy 949** of the result string if the string is non-NULL. 950** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 951** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 952** that the VFS encountered an error while handling the [PRAGMA] and the 953** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 954** file control occurs at the beginning of pragma statement analysis and so 955** it is able to override built-in [PRAGMA] statements. 956** 957** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 958** ^The [SQLITE_FCNTL_BUSYHANDLER] 959** file-control may be invoked by SQLite on the database file handle 960** shortly after it is opened in order to provide a custom VFS with access 961** to the connections busy-handler callback. The argument is of type (void **) 962** - an array of two (void *) values. The first (void *) actually points 963** to a function of type (int (*)(void *)). In order to invoke the connections 964** busy-handler, this function should be invoked with the second (void *) in 965** the array as the only argument. If it returns non-zero, then the operation 966** should be retried. If it returns zero, the custom VFS should abandon the 967** current operation. 968** 969** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 970** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 971** to have SQLite generate a 972** temporary filename using the same algorithm that is followed to generate 973** temporary filenames for TEMP tables and other internal uses. The 974** argument should be a char** which will be filled with the filename 975** written into memory obtained from [sqlite3_malloc()]. The caller should 976** invoke [sqlite3_free()] on the result to avoid a memory leak. 977** 978** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 979** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 980** maximum number of bytes that will be used for memory-mapped I/O. 981** The argument is a pointer to a value of type sqlite3_int64 that 982** is an advisory maximum number of bytes in the file to memory map. The 983** pointer is overwritten with the old value. The limit is not changed if 984** the value originally pointed to is negative, and so the current limit 985** can be queried by passing in a pointer to a negative number. This 986** file-control is used internally to implement [PRAGMA mmap_size]. 987** 988** <li>[[SQLITE_FCNTL_TRACE]] 989** The [SQLITE_FCNTL_TRACE] file control provides advisory information 990** to the VFS about what the higher layers of the SQLite stack are doing. 991** This file control is used by some VFS activity tracing [shims]. 992** The argument is a zero-terminated string. Higher layers in the 993** SQLite stack may generate instances of this file control if 994** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 995** 996** <li>[[SQLITE_FCNTL_HAS_MOVED]] 997** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 998** pointer to an integer and it writes a boolean into that integer depending 999** on whether or not the file has been renamed, moved, or deleted since it 1000** was first opened. 1001** 1002** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1003** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1004** underlying native file handle associated with a file handle. This file 1005** control interprets its argument as a pointer to a native file handle and 1006** writes the resulting value there. 1007** 1008** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1009** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1010** opcode causes the xFileControl method to swap the file handle with the one 1011** pointed to by the pArg argument. This capability is used during testing 1012** and only needs to be supported when SQLITE_TEST is defined. 1013** 1014** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1015** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1016** be advantageous to block on the next WAL lock if the lock is not immediately 1017** available. The WAL subsystem issues this signal during rare 1018** circumstances in order to fix a problem with priority inversion. 1019** Applications should <em>not</em> use this file-control. 1020** 1021** <li>[[SQLITE_FCNTL_ZIPVFS]] 1022** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1023** VFS should return SQLITE_NOTFOUND for this opcode. 1024** 1025** <li>[[SQLITE_FCNTL_RBU]] 1026** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1027** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1028** this opcode. 1029** 1030** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1031** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1032** the file descriptor is placed in "batch write mode", which 1033** means all subsequent write operations will be deferred and done 1034** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1035** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1036** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1037** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1038** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1039** no VFS interface calls on the same [sqlite3_file] file descriptor 1040** except for calls to the xWrite method and the xFileControl method 1041** with [SQLITE_FCNTL_SIZE_HINT]. 1042** 1043** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1044** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1045** operations since the previous successful call to 1046** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1047** This file control returns [SQLITE_OK] if and only if the writes were 1048** all performed successfully and have been committed to persistent storage. 1049** ^Regardless of whether or not it is successful, this file control takes 1050** the file descriptor out of batch write mode so that all subsequent 1051** write operations are independent. 1052** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1053** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1054** 1055** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1056** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1057** operations since the previous successful call to 1058** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1059** ^This file control takes the file descriptor out of batch write mode 1060** so that all subsequent write operations are independent. 1061** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1062** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1063** </ul> 1064*/ 1065#define SQLITE_FCNTL_LOCKSTATE 1 1066#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1067#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1068#define SQLITE_FCNTL_LAST_ERRNO 4 1069#define SQLITE_FCNTL_SIZE_HINT 5 1070#define SQLITE_FCNTL_CHUNK_SIZE 6 1071#define SQLITE_FCNTL_FILE_POINTER 7 1072#define SQLITE_FCNTL_SYNC_OMITTED 8 1073#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1074#define SQLITE_FCNTL_PERSIST_WAL 10 1075#define SQLITE_FCNTL_OVERWRITE 11 1076#define SQLITE_FCNTL_VFSNAME 12 1077#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1078#define SQLITE_FCNTL_PRAGMA 14 1079#define SQLITE_FCNTL_BUSYHANDLER 15 1080#define SQLITE_FCNTL_TEMPFILENAME 16 1081#define SQLITE_FCNTL_MMAP_SIZE 18 1082#define SQLITE_FCNTL_TRACE 19 1083#define SQLITE_FCNTL_HAS_MOVED 20 1084#define SQLITE_FCNTL_SYNC 21 1085#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1086#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1087#define SQLITE_FCNTL_WAL_BLOCK 24 1088#define SQLITE_FCNTL_ZIPVFS 25 1089#define SQLITE_FCNTL_RBU 26 1090#define SQLITE_FCNTL_VFS_POINTER 27 1091#define SQLITE_FCNTL_JOURNAL_POINTER 28 1092#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1093#define SQLITE_FCNTL_PDB 30 1094#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1095#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1096#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1097 1098/* deprecated names */ 1099#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1100#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1101#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1102 1103 1104/* 1105** CAPI3REF: Mutex Handle 1106** 1107** The mutex module within SQLite defines [sqlite3_mutex] to be an 1108** abstract type for a mutex object. The SQLite core never looks 1109** at the internal representation of an [sqlite3_mutex]. It only 1110** deals with pointers to the [sqlite3_mutex] object. 1111** 1112** Mutexes are created using [sqlite3_mutex_alloc()]. 1113*/ 1114typedef struct sqlite3_mutex sqlite3_mutex; 1115 1116/* 1117** CAPI3REF: Loadable Extension Thunk 1118** 1119** A pointer to the opaque sqlite3_api_routines structure is passed as 1120** the third parameter to entry points of [loadable extensions]. This 1121** structure must be typedefed in order to work around compiler warnings 1122** on some platforms. 1123*/ 1124typedef struct sqlite3_api_routines sqlite3_api_routines; 1125 1126/* 1127** CAPI3REF: OS Interface Object 1128** 1129** An instance of the sqlite3_vfs object defines the interface between 1130** the SQLite core and the underlying operating system. The "vfs" 1131** in the name of the object stands for "virtual file system". See 1132** the [VFS | VFS documentation] for further information. 1133** 1134** The VFS interface is sometimes extended by adding new methods onto 1135** the end. Each time such an extension occurs, the iVersion field 1136** is incremented. The iVersion value started out as 1 in 1137** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1138** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1139** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1140** may be appended to the sqlite3_vfs object and the iVersion value 1141** may increase again in future versions of SQLite. 1142** Note that the structure 1143** of the sqlite3_vfs object changes in the transition from 1144** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1145** and yet the iVersion field was not modified. 1146** 1147** The szOsFile field is the size of the subclassed [sqlite3_file] 1148** structure used by this VFS. mxPathname is the maximum length of 1149** a pathname in this VFS. 1150** 1151** Registered sqlite3_vfs objects are kept on a linked list formed by 1152** the pNext pointer. The [sqlite3_vfs_register()] 1153** and [sqlite3_vfs_unregister()] interfaces manage this list 1154** in a thread-safe way. The [sqlite3_vfs_find()] interface 1155** searches the list. Neither the application code nor the VFS 1156** implementation should use the pNext pointer. 1157** 1158** The pNext field is the only field in the sqlite3_vfs 1159** structure that SQLite will ever modify. SQLite will only access 1160** or modify this field while holding a particular static mutex. 1161** The application should never modify anything within the sqlite3_vfs 1162** object once the object has been registered. 1163** 1164** The zName field holds the name of the VFS module. The name must 1165** be unique across all VFS modules. 1166** 1167** [[sqlite3_vfs.xOpen]] 1168** ^SQLite guarantees that the zFilename parameter to xOpen 1169** is either a NULL pointer or string obtained 1170** from xFullPathname() with an optional suffix added. 1171** ^If a suffix is added to the zFilename parameter, it will 1172** consist of a single "-" character followed by no more than 1173** 11 alphanumeric and/or "-" characters. 1174** ^SQLite further guarantees that 1175** the string will be valid and unchanged until xClose() is 1176** called. Because of the previous sentence, 1177** the [sqlite3_file] can safely store a pointer to the 1178** filename if it needs to remember the filename for some reason. 1179** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1180** must invent its own temporary name for the file. ^Whenever the 1181** xFilename parameter is NULL it will also be the case that the 1182** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1183** 1184** The flags argument to xOpen() includes all bits set in 1185** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1186** or [sqlite3_open16()] is used, then flags includes at least 1187** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1188** If xOpen() opens a file read-only then it sets *pOutFlags to 1189** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1190** 1191** ^(SQLite will also add one of the following flags to the xOpen() 1192** call, depending on the object being opened: 1193** 1194** <ul> 1195** <li> [SQLITE_OPEN_MAIN_DB] 1196** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1197** <li> [SQLITE_OPEN_TEMP_DB] 1198** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1199** <li> [SQLITE_OPEN_TRANSIENT_DB] 1200** <li> [SQLITE_OPEN_SUBJOURNAL] 1201** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1202** <li> [SQLITE_OPEN_WAL] 1203** </ul>)^ 1204** 1205** The file I/O implementation can use the object type flags to 1206** change the way it deals with files. For example, an application 1207** that does not care about crash recovery or rollback might make 1208** the open of a journal file a no-op. Writes to this journal would 1209** also be no-ops, and any attempt to read the journal would return 1210** SQLITE_IOERR. Or the implementation might recognize that a database 1211** file will be doing page-aligned sector reads and writes in a random 1212** order and set up its I/O subsystem accordingly. 1213** 1214** SQLite might also add one of the following flags to the xOpen method: 1215** 1216** <ul> 1217** <li> [SQLITE_OPEN_DELETEONCLOSE] 1218** <li> [SQLITE_OPEN_EXCLUSIVE] 1219** </ul> 1220** 1221** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1222** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1223** will be set for TEMP databases and their journals, transient 1224** databases, and subjournals. 1225** 1226** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1227** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1228** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1229** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1230** SQLITE_OPEN_CREATE, is used to indicate that file should always 1231** be created, and that it is an error if it already exists. 1232** It is <i>not</i> used to indicate the file should be opened 1233** for exclusive access. 1234** 1235** ^At least szOsFile bytes of memory are allocated by SQLite 1236** to hold the [sqlite3_file] structure passed as the third 1237** argument to xOpen. The xOpen method does not have to 1238** allocate the structure; it should just fill it in. Note that 1239** the xOpen method must set the sqlite3_file.pMethods to either 1240** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1241** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1242** element will be valid after xOpen returns regardless of the success 1243** or failure of the xOpen call. 1244** 1245** [[sqlite3_vfs.xAccess]] 1246** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1247** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1248** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1249** to test whether a file is at least readable. The file can be a 1250** directory. 1251** 1252** ^SQLite will always allocate at least mxPathname+1 bytes for the 1253** output buffer xFullPathname. The exact size of the output buffer 1254** is also passed as a parameter to both methods. If the output buffer 1255** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1256** handled as a fatal error by SQLite, vfs implementations should endeavor 1257** to prevent this by setting mxPathname to a sufficiently large value. 1258** 1259** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1260** interfaces are not strictly a part of the filesystem, but they are 1261** included in the VFS structure for completeness. 1262** The xRandomness() function attempts to return nBytes bytes 1263** of good-quality randomness into zOut. The return value is 1264** the actual number of bytes of randomness obtained. 1265** The xSleep() method causes the calling thread to sleep for at 1266** least the number of microseconds given. ^The xCurrentTime() 1267** method returns a Julian Day Number for the current date and time as 1268** a floating point value. 1269** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1270** Day Number multiplied by 86400000 (the number of milliseconds in 1271** a 24-hour day). 1272** ^SQLite will use the xCurrentTimeInt64() method to get the current 1273** date and time if that method is available (if iVersion is 2 or 1274** greater and the function pointer is not NULL) and will fall back 1275** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1276** 1277** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1278** are not used by the SQLite core. These optional interfaces are provided 1279** by some VFSes to facilitate testing of the VFS code. By overriding 1280** system calls with functions under its control, a test program can 1281** simulate faults and error conditions that would otherwise be difficult 1282** or impossible to induce. The set of system calls that can be overridden 1283** varies from one VFS to another, and from one version of the same VFS to the 1284** next. Applications that use these interfaces must be prepared for any 1285** or all of these interfaces to be NULL or for their behavior to change 1286** from one release to the next. Applications must not attempt to access 1287** any of these methods if the iVersion of the VFS is less than 3. 1288*/ 1289typedef struct sqlite3_vfs sqlite3_vfs; 1290typedef void (*sqlite3_syscall_ptr)(void); 1291struct sqlite3_vfs { 1292 int iVersion; /* Structure version number (currently 3) */ 1293 int szOsFile; /* Size of subclassed sqlite3_file */ 1294 int mxPathname; /* Maximum file pathname length */ 1295 sqlite3_vfs *pNext; /* Next registered VFS */ 1296 const char *zName; /* Name of this virtual file system */ 1297 void *pAppData; /* Pointer to application-specific data */ 1298 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1299 int flags, int *pOutFlags); 1300 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1301 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1302 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1303 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1304 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1305 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1306 void (*xDlClose)(sqlite3_vfs*, void*); 1307 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1308 int (*xSleep)(sqlite3_vfs*, int microseconds); 1309 int (*xCurrentTime)(sqlite3_vfs*, double*); 1310 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1311 /* 1312 ** The methods above are in version 1 of the sqlite_vfs object 1313 ** definition. Those that follow are added in version 2 or later 1314 */ 1315 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1316 /* 1317 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1318 ** Those below are for version 3 and greater. 1319 */ 1320 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1321 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1322 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1323 /* 1324 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1325 ** New fields may be appended in future versions. The iVersion 1326 ** value will increment whenever this happens. 1327 */ 1328}; 1329 1330/* 1331** CAPI3REF: Flags for the xAccess VFS method 1332** 1333** These integer constants can be used as the third parameter to 1334** the xAccess method of an [sqlite3_vfs] object. They determine 1335** what kind of permissions the xAccess method is looking for. 1336** With SQLITE_ACCESS_EXISTS, the xAccess method 1337** simply checks whether the file exists. 1338** With SQLITE_ACCESS_READWRITE, the xAccess method 1339** checks whether the named directory is both readable and writable 1340** (in other words, if files can be added, removed, and renamed within 1341** the directory). 1342** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1343** [temp_store_directory pragma], though this could change in a future 1344** release of SQLite. 1345** With SQLITE_ACCESS_READ, the xAccess method 1346** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1347** currently unused, though it might be used in a future release of 1348** SQLite. 1349*/ 1350#define SQLITE_ACCESS_EXISTS 0 1351#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1352#define SQLITE_ACCESS_READ 2 /* Unused */ 1353 1354/* 1355** CAPI3REF: Flags for the xShmLock VFS method 1356** 1357** These integer constants define the various locking operations 1358** allowed by the xShmLock method of [sqlite3_io_methods]. The 1359** following are the only legal combinations of flags to the 1360** xShmLock method: 1361** 1362** <ul> 1363** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1364** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1365** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1366** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1367** </ul> 1368** 1369** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1370** was given on the corresponding lock. 1371** 1372** The xShmLock method can transition between unlocked and SHARED or 1373** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1374** and EXCLUSIVE. 1375*/ 1376#define SQLITE_SHM_UNLOCK 1 1377#define SQLITE_SHM_LOCK 2 1378#define SQLITE_SHM_SHARED 4 1379#define SQLITE_SHM_EXCLUSIVE 8 1380 1381/* 1382** CAPI3REF: Maximum xShmLock index 1383** 1384** The xShmLock method on [sqlite3_io_methods] may use values 1385** between 0 and this upper bound as its "offset" argument. 1386** The SQLite core will never attempt to acquire or release a 1387** lock outside of this range 1388*/ 1389#define SQLITE_SHM_NLOCK 8 1390 1391 1392/* 1393** CAPI3REF: Initialize The SQLite Library 1394** 1395** ^The sqlite3_initialize() routine initializes the 1396** SQLite library. ^The sqlite3_shutdown() routine 1397** deallocates any resources that were allocated by sqlite3_initialize(). 1398** These routines are designed to aid in process initialization and 1399** shutdown on embedded systems. Workstation applications using 1400** SQLite normally do not need to invoke either of these routines. 1401** 1402** A call to sqlite3_initialize() is an "effective" call if it is 1403** the first time sqlite3_initialize() is invoked during the lifetime of 1404** the process, or if it is the first time sqlite3_initialize() is invoked 1405** following a call to sqlite3_shutdown(). ^(Only an effective call 1406** of sqlite3_initialize() does any initialization. All other calls 1407** are harmless no-ops.)^ 1408** 1409** A call to sqlite3_shutdown() is an "effective" call if it is the first 1410** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1411** an effective call to sqlite3_shutdown() does any deinitialization. 1412** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1413** 1414** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1415** is not. The sqlite3_shutdown() interface must only be called from a 1416** single thread. All open [database connections] must be closed and all 1417** other SQLite resources must be deallocated prior to invoking 1418** sqlite3_shutdown(). 1419** 1420** Among other things, ^sqlite3_initialize() will invoke 1421** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1422** will invoke sqlite3_os_end(). 1423** 1424** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1425** ^If for some reason, sqlite3_initialize() is unable to initialize 1426** the library (perhaps it is unable to allocate a needed resource such 1427** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1428** 1429** ^The sqlite3_initialize() routine is called internally by many other 1430** SQLite interfaces so that an application usually does not need to 1431** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1432** calls sqlite3_initialize() so the SQLite library will be automatically 1433** initialized when [sqlite3_open()] is called if it has not be initialized 1434** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1435** compile-time option, then the automatic calls to sqlite3_initialize() 1436** are omitted and the application must call sqlite3_initialize() directly 1437** prior to using any other SQLite interface. For maximum portability, 1438** it is recommended that applications always invoke sqlite3_initialize() 1439** directly prior to using any other SQLite interface. Future releases 1440** of SQLite may require this. In other words, the behavior exhibited 1441** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1442** default behavior in some future release of SQLite. 1443** 1444** The sqlite3_os_init() routine does operating-system specific 1445** initialization of the SQLite library. The sqlite3_os_end() 1446** routine undoes the effect of sqlite3_os_init(). Typical tasks 1447** performed by these routines include allocation or deallocation 1448** of static resources, initialization of global variables, 1449** setting up a default [sqlite3_vfs] module, or setting up 1450** a default configuration using [sqlite3_config()]. 1451** 1452** The application should never invoke either sqlite3_os_init() 1453** or sqlite3_os_end() directly. The application should only invoke 1454** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1455** interface is called automatically by sqlite3_initialize() and 1456** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1457** implementations for sqlite3_os_init() and sqlite3_os_end() 1458** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1459** When [custom builds | built for other platforms] 1460** (using the [SQLITE_OS_OTHER=1] compile-time 1461** option) the application must supply a suitable implementation for 1462** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1463** implementation of sqlite3_os_init() or sqlite3_os_end() 1464** must return [SQLITE_OK] on success and some other [error code] upon 1465** failure. 1466*/ 1467int sqlite3_initialize(void); 1468int sqlite3_shutdown(void); 1469int sqlite3_os_init(void); 1470int sqlite3_os_end(void); 1471 1472/* 1473** CAPI3REF: Configuring The SQLite Library 1474** 1475** The sqlite3_config() interface is used to make global configuration 1476** changes to SQLite in order to tune SQLite to the specific needs of 1477** the application. The default configuration is recommended for most 1478** applications and so this routine is usually not necessary. It is 1479** provided to support rare applications with unusual needs. 1480** 1481** <b>The sqlite3_config() interface is not threadsafe. The application 1482** must ensure that no other SQLite interfaces are invoked by other 1483** threads while sqlite3_config() is running.</b> 1484** 1485** The sqlite3_config() interface 1486** may only be invoked prior to library initialization using 1487** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1488** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1489** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1490** Note, however, that ^sqlite3_config() can be called as part of the 1491** implementation of an application-defined [sqlite3_os_init()]. 1492** 1493** The first argument to sqlite3_config() is an integer 1494** [configuration option] that determines 1495** what property of SQLite is to be configured. Subsequent arguments 1496** vary depending on the [configuration option] 1497** in the first argument. 1498** 1499** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1500** ^If the option is unknown or SQLite is unable to set the option 1501** then this routine returns a non-zero [error code]. 1502*/ 1503int sqlite3_config(int, ...); 1504 1505/* 1506** CAPI3REF: Configure database connections 1507** METHOD: sqlite3 1508** 1509** The sqlite3_db_config() interface is used to make configuration 1510** changes to a [database connection]. The interface is similar to 1511** [sqlite3_config()] except that the changes apply to a single 1512** [database connection] (specified in the first argument). 1513** 1514** The second argument to sqlite3_db_config(D,V,...) is the 1515** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1516** that indicates what aspect of the [database connection] is being configured. 1517** Subsequent arguments vary depending on the configuration verb. 1518** 1519** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1520** the call is considered successful. 1521*/ 1522int sqlite3_db_config(sqlite3*, int op, ...); 1523 1524/* 1525** CAPI3REF: Memory Allocation Routines 1526** 1527** An instance of this object defines the interface between SQLite 1528** and low-level memory allocation routines. 1529** 1530** This object is used in only one place in the SQLite interface. 1531** A pointer to an instance of this object is the argument to 1532** [sqlite3_config()] when the configuration option is 1533** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1534** By creating an instance of this object 1535** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1536** during configuration, an application can specify an alternative 1537** memory allocation subsystem for SQLite to use for all of its 1538** dynamic memory needs. 1539** 1540** Note that SQLite comes with several [built-in memory allocators] 1541** that are perfectly adequate for the overwhelming majority of applications 1542** and that this object is only useful to a tiny minority of applications 1543** with specialized memory allocation requirements. This object is 1544** also used during testing of SQLite in order to specify an alternative 1545** memory allocator that simulates memory out-of-memory conditions in 1546** order to verify that SQLite recovers gracefully from such 1547** conditions. 1548** 1549** The xMalloc, xRealloc, and xFree methods must work like the 1550** malloc(), realloc() and free() functions from the standard C library. 1551** ^SQLite guarantees that the second argument to 1552** xRealloc is always a value returned by a prior call to xRoundup. 1553** 1554** xSize should return the allocated size of a memory allocation 1555** previously obtained from xMalloc or xRealloc. The allocated size 1556** is always at least as big as the requested size but may be larger. 1557** 1558** The xRoundup method returns what would be the allocated size of 1559** a memory allocation given a particular requested size. Most memory 1560** allocators round up memory allocations at least to the next multiple 1561** of 8. Some allocators round up to a larger multiple or to a power of 2. 1562** Every memory allocation request coming in through [sqlite3_malloc()] 1563** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1564** that causes the corresponding memory allocation to fail. 1565** 1566** The xInit method initializes the memory allocator. For example, 1567** it might allocate any require mutexes or initialize internal data 1568** structures. The xShutdown method is invoked (indirectly) by 1569** [sqlite3_shutdown()] and should deallocate any resources acquired 1570** by xInit. The pAppData pointer is used as the only parameter to 1571** xInit and xShutdown. 1572** 1573** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1574** the xInit method, so the xInit method need not be threadsafe. The 1575** xShutdown method is only called from [sqlite3_shutdown()] so it does 1576** not need to be threadsafe either. For all other methods, SQLite 1577** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1578** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1579** it is by default) and so the methods are automatically serialized. 1580** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1581** methods must be threadsafe or else make their own arrangements for 1582** serialization. 1583** 1584** SQLite will never invoke xInit() more than once without an intervening 1585** call to xShutdown(). 1586*/ 1587typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1588struct sqlite3_mem_methods { 1589 void *(*xMalloc)(int); /* Memory allocation function */ 1590 void (*xFree)(void*); /* Free a prior allocation */ 1591 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1592 int (*xSize)(void*); /* Return the size of an allocation */ 1593 int (*xRoundup)(int); /* Round up request size to allocation size */ 1594 int (*xInit)(void*); /* Initialize the memory allocator */ 1595 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1596 void *pAppData; /* Argument to xInit() and xShutdown() */ 1597}; 1598 1599/* 1600** CAPI3REF: Configuration Options 1601** KEYWORDS: {configuration option} 1602** 1603** These constants are the available integer configuration options that 1604** can be passed as the first argument to the [sqlite3_config()] interface. 1605** 1606** New configuration options may be added in future releases of SQLite. 1607** Existing configuration options might be discontinued. Applications 1608** should check the return code from [sqlite3_config()] to make sure that 1609** the call worked. The [sqlite3_config()] interface will return a 1610** non-zero [error code] if a discontinued or unsupported configuration option 1611** is invoked. 1612** 1613** <dl> 1614** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1615** <dd>There are no arguments to this option. ^This option sets the 1616** [threading mode] to Single-thread. In other words, it disables 1617** all mutexing and puts SQLite into a mode where it can only be used 1618** by a single thread. ^If SQLite is compiled with 1619** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1620** it is not possible to change the [threading mode] from its default 1621** value of Single-thread and so [sqlite3_config()] will return 1622** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1623** configuration option.</dd> 1624** 1625** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1626** <dd>There are no arguments to this option. ^This option sets the 1627** [threading mode] to Multi-thread. In other words, it disables 1628** mutexing on [database connection] and [prepared statement] objects. 1629** The application is responsible for serializing access to 1630** [database connections] and [prepared statements]. But other mutexes 1631** are enabled so that SQLite will be safe to use in a multi-threaded 1632** environment as long as no two threads attempt to use the same 1633** [database connection] at the same time. ^If SQLite is compiled with 1634** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1635** it is not possible to set the Multi-thread [threading mode] and 1636** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1637** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1638** 1639** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1640** <dd>There are no arguments to this option. ^This option sets the 1641** [threading mode] to Serialized. In other words, this option enables 1642** all mutexes including the recursive 1643** mutexes on [database connection] and [prepared statement] objects. 1644** In this mode (which is the default when SQLite is compiled with 1645** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1646** to [database connections] and [prepared statements] so that the 1647** application is free to use the same [database connection] or the 1648** same [prepared statement] in different threads at the same time. 1649** ^If SQLite is compiled with 1650** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1651** it is not possible to set the Serialized [threading mode] and 1652** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1653** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1654** 1655** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1656** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1657** a pointer to an instance of the [sqlite3_mem_methods] structure. 1658** The argument specifies 1659** alternative low-level memory allocation routines to be used in place of 1660** the memory allocation routines built into SQLite.)^ ^SQLite makes 1661** its own private copy of the content of the [sqlite3_mem_methods] structure 1662** before the [sqlite3_config()] call returns.</dd> 1663** 1664** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1665** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1666** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1667** The [sqlite3_mem_methods] 1668** structure is filled with the currently defined memory allocation routines.)^ 1669** This option can be used to overload the default memory allocation 1670** routines with a wrapper that simulations memory allocation failure or 1671** tracks memory usage, for example. </dd> 1672** 1673** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1674** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1675** type int, interpreted as a boolean, which if true provides a hint to 1676** SQLite that it should avoid large memory allocations if possible. 1677** SQLite will run faster if it is free to make large memory allocations, 1678** but some application might prefer to run slower in exchange for 1679** guarantees about memory fragmentation that are possible if large 1680** allocations are avoided. This hint is normally off. 1681** </dd> 1682** 1683** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1684** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1685** interpreted as a boolean, which enables or disables the collection of 1686** memory allocation statistics. ^(When memory allocation statistics are 1687** disabled, the following SQLite interfaces become non-operational: 1688** <ul> 1689** <li> [sqlite3_memory_used()] 1690** <li> [sqlite3_memory_highwater()] 1691** <li> [sqlite3_soft_heap_limit64()] 1692** <li> [sqlite3_status64()] 1693** </ul>)^ 1694** ^Memory allocation statistics are enabled by default unless SQLite is 1695** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1696** allocation statistics are disabled by default. 1697** </dd> 1698** 1699** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1700** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1701** </dd> 1702** 1703** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1704** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1705** that SQLite can use for the database page cache with the default page 1706** cache implementation. 1707** This configuration option is a no-op if an application-define page 1708** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1709** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1710** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1711** and the number of cache lines (N). 1712** The sz argument should be the size of the largest database page 1713** (a power of two between 512 and 65536) plus some extra bytes for each 1714** page header. ^The number of extra bytes needed by the page header 1715** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1716** ^It is harmless, apart from the wasted memory, 1717** for the sz parameter to be larger than necessary. The pMem 1718** argument must be either a NULL pointer or a pointer to an 8-byte 1719** aligned block of memory of at least sz*N bytes, otherwise 1720** subsequent behavior is undefined. 1721** ^When pMem is not NULL, SQLite will strive to use the memory provided 1722** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1723** a page cache line is larger than sz bytes or if all of the pMem buffer 1724** is exhausted. 1725** ^If pMem is NULL and N is non-zero, then each database connection 1726** does an initial bulk allocation for page cache memory 1727** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1728** of -1024*N bytes if N is negative, . ^If additional 1729** page cache memory is needed beyond what is provided by the initial 1730** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1731** additional cache line. </dd> 1732** 1733** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1734** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1735** that SQLite will use for all of its dynamic memory allocation needs 1736** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1737** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1738** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1739** [SQLITE_ERROR] if invoked otherwise. 1740** ^There are three arguments to SQLITE_CONFIG_HEAP: 1741** An 8-byte aligned pointer to the memory, 1742** the number of bytes in the memory buffer, and the minimum allocation size. 1743** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1744** to using its default memory allocator (the system malloc() implementation), 1745** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1746** memory pointer is not NULL then the alternative memory 1747** allocator is engaged to handle all of SQLites memory allocation needs. 1748** The first pointer (the memory pointer) must be aligned to an 8-byte 1749** boundary or subsequent behavior of SQLite will be undefined. 1750** The minimum allocation size is capped at 2**12. Reasonable values 1751** for the minimum allocation size are 2**5 through 2**8.</dd> 1752** 1753** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1754** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1755** pointer to an instance of the [sqlite3_mutex_methods] structure. 1756** The argument specifies alternative low-level mutex routines to be used 1757** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1758** the content of the [sqlite3_mutex_methods] structure before the call to 1759** [sqlite3_config()] returns. ^If SQLite is compiled with 1760** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1761** the entire mutexing subsystem is omitted from the build and hence calls to 1762** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1763** return [SQLITE_ERROR].</dd> 1764** 1765** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1766** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1767** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1768** [sqlite3_mutex_methods] 1769** structure is filled with the currently defined mutex routines.)^ 1770** This option can be used to overload the default mutex allocation 1771** routines with a wrapper used to track mutex usage for performance 1772** profiling or testing, for example. ^If SQLite is compiled with 1773** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1774** the entire mutexing subsystem is omitted from the build and hence calls to 1775** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1776** return [SQLITE_ERROR].</dd> 1777** 1778** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1779** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1780** the default size of lookaside memory on each [database connection]. 1781** The first argument is the 1782** size of each lookaside buffer slot and the second is the number of 1783** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1784** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1785** option to [sqlite3_db_config()] can be used to change the lookaside 1786** configuration on individual connections.)^ </dd> 1787** 1788** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1789** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1790** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1791** the interface to a custom page cache implementation.)^ 1792** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1793** 1794** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1795** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1796** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1797** the current page cache implementation into that object.)^ </dd> 1798** 1799** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1800** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1801** global [error log]. 1802** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1803** function with a call signature of void(*)(void*,int,const char*), 1804** and a pointer to void. ^If the function pointer is not NULL, it is 1805** invoked by [sqlite3_log()] to process each logging event. ^If the 1806** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1807** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1808** passed through as the first parameter to the application-defined logger 1809** function whenever that function is invoked. ^The second parameter to 1810** the logger function is a copy of the first parameter to the corresponding 1811** [sqlite3_log()] call and is intended to be a [result code] or an 1812** [extended result code]. ^The third parameter passed to the logger is 1813** log message after formatting via [sqlite3_snprintf()]. 1814** The SQLite logging interface is not reentrant; the logger function 1815** supplied by the application must not invoke any SQLite interface. 1816** In a multi-threaded application, the application-defined logger 1817** function must be threadsafe. </dd> 1818** 1819** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1820** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1821** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1822** then URI handling is globally disabled.)^ ^If URI handling is globally 1823** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1824** [sqlite3_open16()] or 1825** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1826** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1827** connection is opened. ^If it is globally disabled, filenames are 1828** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1829** database connection is opened. ^(By default, URI handling is globally 1830** disabled. The default value may be changed by compiling with the 1831** [SQLITE_USE_URI] symbol defined.)^ 1832** 1833** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1834** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1835** argument which is interpreted as a boolean in order to enable or disable 1836** the use of covering indices for full table scans in the query optimizer. 1837** ^The default setting is determined 1838** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1839** if that compile-time option is omitted. 1840** The ability to disable the use of covering indices for full table scans 1841** is because some incorrectly coded legacy applications might malfunction 1842** when the optimization is enabled. Providing the ability to 1843** disable the optimization allows the older, buggy application code to work 1844** without change even with newer versions of SQLite. 1845** 1846** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1847** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1848** <dd> These options are obsolete and should not be used by new code. 1849** They are retained for backwards compatibility but are now no-ops. 1850** </dd> 1851** 1852** [[SQLITE_CONFIG_SQLLOG]] 1853** <dt>SQLITE_CONFIG_SQLLOG 1854** <dd>This option is only available if sqlite is compiled with the 1855** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1856** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1857** The second should be of type (void*). The callback is invoked by the library 1858** in three separate circumstances, identified by the value passed as the 1859** fourth parameter. If the fourth parameter is 0, then the database connection 1860** passed as the second argument has just been opened. The third argument 1861** points to a buffer containing the name of the main database file. If the 1862** fourth parameter is 1, then the SQL statement that the third parameter 1863** points to has just been executed. Or, if the fourth parameter is 2, then 1864** the connection being passed as the second parameter is being closed. The 1865** third parameter is passed NULL In this case. An example of using this 1866** configuration option can be seen in the "test_sqllog.c" source file in 1867** the canonical SQLite source tree.</dd> 1868** 1869** [[SQLITE_CONFIG_MMAP_SIZE]] 1870** <dt>SQLITE_CONFIG_MMAP_SIZE 1871** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1872** that are the default mmap size limit (the default setting for 1873** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1874** ^The default setting can be overridden by each database connection using 1875** either the [PRAGMA mmap_size] command, or by using the 1876** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1877** will be silently truncated if necessary so that it does not exceed the 1878** compile-time maximum mmap size set by the 1879** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1880** ^If either argument to this option is negative, then that argument is 1881** changed to its compile-time default. 1882** 1883** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1884** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1885** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1886** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1887** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1888** that specifies the maximum size of the created heap. 1889** 1890** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1891** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1892** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1893** is a pointer to an integer and writes into that integer the number of extra 1894** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1895** The amount of extra space required can change depending on the compiler, 1896** target platform, and SQLite version. 1897** 1898** [[SQLITE_CONFIG_PMASZ]] 1899** <dt>SQLITE_CONFIG_PMASZ 1900** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1901** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1902** sorter to that integer. The default minimum PMA Size is set by the 1903** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1904** to help with sort operations when multithreaded sorting 1905** is enabled (using the [PRAGMA threads] command) and the amount of content 1906** to be sorted exceeds the page size times the minimum of the 1907** [PRAGMA cache_size] setting and this value. 1908** 1909** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1910** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1911** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1912** becomes the [statement journal] spill-to-disk threshold. 1913** [Statement journals] are held in memory until their size (in bytes) 1914** exceeds this threshold, at which point they are written to disk. 1915** Or if the threshold is -1, statement journals are always held 1916** exclusively in memory. 1917** Since many statement journals never become large, setting the spill 1918** threshold to a value such as 64KiB can greatly reduce the amount of 1919** I/O required to support statement rollback. 1920** The default value for this setting is controlled by the 1921** [SQLITE_STMTJRNL_SPILL] compile-time option. 1922** </dl> 1923*/ 1924#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1925#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1926#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1927#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1928#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1929#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1930#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1931#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1932#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1933#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1934#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1935/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1936#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1937#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1938#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1939#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1940#define SQLITE_CONFIG_URI 17 /* int */ 1941#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1942#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1943#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1944#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1945#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1946#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1947#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1948#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1949#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1950#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1951 1952/* 1953** CAPI3REF: Database Connection Configuration Options 1954** 1955** These constants are the available integer configuration options that 1956** can be passed as the second argument to the [sqlite3_db_config()] interface. 1957** 1958** New configuration options may be added in future releases of SQLite. 1959** Existing configuration options might be discontinued. Applications 1960** should check the return code from [sqlite3_db_config()] to make sure that 1961** the call worked. ^The [sqlite3_db_config()] interface will return a 1962** non-zero [error code] if a discontinued or unsupported configuration option 1963** is invoked. 1964** 1965** <dl> 1966** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1967** <dd> ^This option takes three additional arguments that determine the 1968** [lookaside memory allocator] configuration for the [database connection]. 1969** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1970** pointer to a memory buffer to use for lookaside memory. 1971** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1972** may be NULL in which case SQLite will allocate the 1973** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1974** size of each lookaside buffer slot. ^The third argument is the number of 1975** slots. The size of the buffer in the first argument must be greater than 1976** or equal to the product of the second and third arguments. The buffer 1977** must be aligned to an 8-byte boundary. ^If the second argument to 1978** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1979** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1980** configuration for a database connection can only be changed when that 1981** connection is not currently using lookaside memory, or in other words 1982** when the "current value" returned by 1983** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1984** Any attempt to change the lookaside memory configuration when lookaside 1985** memory is in use leaves the configuration unchanged and returns 1986** [SQLITE_BUSY].)^</dd> 1987** 1988** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1989** <dd> ^This option is used to enable or disable the enforcement of 1990** [foreign key constraints]. There should be two additional arguments. 1991** The first argument is an integer which is 0 to disable FK enforcement, 1992** positive to enable FK enforcement or negative to leave FK enforcement 1993** unchanged. The second parameter is a pointer to an integer into which 1994** is written 0 or 1 to indicate whether FK enforcement is off or on 1995** following this call. The second parameter may be a NULL pointer, in 1996** which case the FK enforcement setting is not reported back. </dd> 1997** 1998** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1999** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2000** There should be two additional arguments. 2001** The first argument is an integer which is 0 to disable triggers, 2002** positive to enable triggers or negative to leave the setting unchanged. 2003** The second parameter is a pointer to an integer into which 2004** is written 0 or 1 to indicate whether triggers are disabled or enabled 2005** following this call. The second parameter may be a NULL pointer, in 2006** which case the trigger setting is not reported back. </dd> 2007** 2008** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2009** <dd> ^This option is used to enable or disable the two-argument 2010** version of the [fts3_tokenizer()] function which is part of the 2011** [FTS3] full-text search engine extension. 2012** There should be two additional arguments. 2013** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2014** positive to enable fts3_tokenizer() or negative to leave the setting 2015** unchanged. 2016** The second parameter is a pointer to an integer into which 2017** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2018** following this call. The second parameter may be a NULL pointer, in 2019** which case the new setting is not reported back. </dd> 2020** 2021** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2022** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2023** interface independently of the [load_extension()] SQL function. 2024** The [sqlite3_enable_load_extension()] API enables or disables both the 2025** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2026** There should be two additional arguments. 2027** When the first argument to this interface is 1, then only the C-API is 2028** enabled and the SQL function remains disabled. If the first argument to 2029** this interface is 0, then both the C-API and the SQL function are disabled. 2030** If the first argument is -1, then no changes are made to state of either the 2031** C-API or the SQL function. 2032** The second parameter is a pointer to an integer into which 2033** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2034** is disabled or enabled following this call. The second parameter may 2035** be a NULL pointer, in which case the new setting is not reported back. 2036** </dd> 2037** 2038** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2039** <dd> ^This option is used to change the name of the "main" database 2040** schema. ^The sole argument is a pointer to a constant UTF8 string 2041** which will become the new schema name in place of "main". ^SQLite 2042** does not make a copy of the new main schema name string, so the application 2043** must ensure that the argument passed into this DBCONFIG option is unchanged 2044** until after the database connection closes. 2045** </dd> 2046** 2047** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2048** <dd> Usually, when a database in wal mode is closed or detached from a 2049** database handle, SQLite checks if this will mean that there are now no 2050** connections at all to the database. If so, it performs a checkpoint 2051** operation before closing the connection. This option may be used to 2052** override this behaviour. The first parameter passed to this operation 2053** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2054** default) to enable them. The second parameter is a pointer to an integer 2055** into which is written 0 or 1 to indicate whether checkpoints-on-close 2056** have been disabled - 0 if they are not disabled, 1 if they are. 2057** </dd> 2058** 2059** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2060** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2061** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2062** a single SQL query statement will always use the same algorithm regardless 2063** of values of [bound parameters].)^ The QPSG disables some query optimizations 2064** that look at the values of bound parameters, which can make some queries 2065** slower. But the QPSG has the advantage of more predictable behavior. With 2066** the QPSG active, SQLite will always use the same query plan in the field as 2067** was used during testing in the lab. 2068** </dd> 2069** 2070** </dl> 2071*/ 2072#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2073#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2074#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2075#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2076#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2077#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2078#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2079#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2080 2081 2082/* 2083** CAPI3REF: Enable Or Disable Extended Result Codes 2084** METHOD: sqlite3 2085** 2086** ^The sqlite3_extended_result_codes() routine enables or disables the 2087** [extended result codes] feature of SQLite. ^The extended result 2088** codes are disabled by default for historical compatibility. 2089*/ 2090int sqlite3_extended_result_codes(sqlite3*, int onoff); 2091 2092/* 2093** CAPI3REF: Last Insert Rowid 2094** METHOD: sqlite3 2095** 2096** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2097** has a unique 64-bit signed 2098** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2099** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2100** names are not also used by explicitly declared columns. ^If 2101** the table has a column of type [INTEGER PRIMARY KEY] then that column 2102** is another alias for the rowid. 2103** 2104** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2105** the most recent successful [INSERT] into a rowid table or [virtual table] 2106** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2107** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2108** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2109** zero. 2110** 2111** As well as being set automatically as rows are inserted into database 2112** tables, the value returned by this function may be set explicitly by 2113** [sqlite3_set_last_insert_rowid()] 2114** 2115** Some virtual table implementations may INSERT rows into rowid tables as 2116** part of committing a transaction (e.g. to flush data accumulated in memory 2117** to disk). In this case subsequent calls to this function return the rowid 2118** associated with these internal INSERT operations, which leads to 2119** unintuitive results. Virtual table implementations that do write to rowid 2120** tables in this way can avoid this problem by restoring the original 2121** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2122** control to the user. 2123** 2124** ^(If an [INSERT] occurs within a trigger then this routine will 2125** return the [rowid] of the inserted row as long as the trigger is 2126** running. Once the trigger program ends, the value returned 2127** by this routine reverts to what it was before the trigger was fired.)^ 2128** 2129** ^An [INSERT] that fails due to a constraint violation is not a 2130** successful [INSERT] and does not change the value returned by this 2131** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2132** and INSERT OR ABORT make no changes to the return value of this 2133** routine when their insertion fails. ^(When INSERT OR REPLACE 2134** encounters a constraint violation, it does not fail. The 2135** INSERT continues to completion after deleting rows that caused 2136** the constraint problem so INSERT OR REPLACE will always change 2137** the return value of this interface.)^ 2138** 2139** ^For the purposes of this routine, an [INSERT] is considered to 2140** be successful even if it is subsequently rolled back. 2141** 2142** This function is accessible to SQL statements via the 2143** [last_insert_rowid() SQL function]. 2144** 2145** If a separate thread performs a new [INSERT] on the same 2146** database connection while the [sqlite3_last_insert_rowid()] 2147** function is running and thus changes the last insert [rowid], 2148** then the value returned by [sqlite3_last_insert_rowid()] is 2149** unpredictable and might not equal either the old or the new 2150** last insert [rowid]. 2151*/ 2152sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2153 2154/* 2155** CAPI3REF: Set the Last Insert Rowid value. 2156** METHOD: sqlite3 2157** 2158** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2159** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2160** without inserting a row into the database. 2161*/ 2162void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2163 2164/* 2165** CAPI3REF: Count The Number Of Rows Modified 2166** METHOD: sqlite3 2167** 2168** ^This function returns the number of rows modified, inserted or 2169** deleted by the most recently completed INSERT, UPDATE or DELETE 2170** statement on the database connection specified by the only parameter. 2171** ^Executing any other type of SQL statement does not modify the value 2172** returned by this function. 2173** 2174** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2175** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2176** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2177** 2178** Changes to a view that are intercepted by 2179** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2180** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2181** DELETE statement run on a view is always zero. Only changes made to real 2182** tables are counted. 2183** 2184** Things are more complicated if the sqlite3_changes() function is 2185** executed while a trigger program is running. This may happen if the 2186** program uses the [changes() SQL function], or if some other callback 2187** function invokes sqlite3_changes() directly. Essentially: 2188** 2189** <ul> 2190** <li> ^(Before entering a trigger program the value returned by 2191** sqlite3_changes() function is saved. After the trigger program 2192** has finished, the original value is restored.)^ 2193** 2194** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2195** statement sets the value returned by sqlite3_changes() 2196** upon completion as normal. Of course, this value will not include 2197** any changes performed by sub-triggers, as the sqlite3_changes() 2198** value will be saved and restored after each sub-trigger has run.)^ 2199** </ul> 2200** 2201** ^This means that if the changes() SQL function (or similar) is used 2202** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2203** returns the value as set when the calling statement began executing. 2204** ^If it is used by the second or subsequent such statement within a trigger 2205** program, the value returned reflects the number of rows modified by the 2206** previous INSERT, UPDATE or DELETE statement within the same trigger. 2207** 2208** See also the [sqlite3_total_changes()] interface, the 2209** [count_changes pragma], and the [changes() SQL function]. 2210** 2211** If a separate thread makes changes on the same database connection 2212** while [sqlite3_changes()] is running then the value returned 2213** is unpredictable and not meaningful. 2214*/ 2215int sqlite3_changes(sqlite3*); 2216 2217/* 2218** CAPI3REF: Total Number Of Rows Modified 2219** METHOD: sqlite3 2220** 2221** ^This function returns the total number of rows inserted, modified or 2222** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2223** since the database connection was opened, including those executed as 2224** part of trigger programs. ^Executing any other type of SQL statement 2225** does not affect the value returned by sqlite3_total_changes(). 2226** 2227** ^Changes made as part of [foreign key actions] are included in the 2228** count, but those made as part of REPLACE constraint resolution are 2229** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2230** are not counted. 2231** 2232** See also the [sqlite3_changes()] interface, the 2233** [count_changes pragma], and the [total_changes() SQL function]. 2234** 2235** If a separate thread makes changes on the same database connection 2236** while [sqlite3_total_changes()] is running then the value 2237** returned is unpredictable and not meaningful. 2238*/ 2239int sqlite3_total_changes(sqlite3*); 2240 2241/* 2242** CAPI3REF: Interrupt A Long-Running Query 2243** METHOD: sqlite3 2244** 2245** ^This function causes any pending database operation to abort and 2246** return at its earliest opportunity. This routine is typically 2247** called in response to a user action such as pressing "Cancel" 2248** or Ctrl-C where the user wants a long query operation to halt 2249** immediately. 2250** 2251** ^It is safe to call this routine from a thread different from the 2252** thread that is currently running the database operation. But it 2253** is not safe to call this routine with a [database connection] that 2254** is closed or might close before sqlite3_interrupt() returns. 2255** 2256** ^If an SQL operation is very nearly finished at the time when 2257** sqlite3_interrupt() is called, then it might not have an opportunity 2258** to be interrupted and might continue to completion. 2259** 2260** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2261** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2262** that is inside an explicit transaction, then the entire transaction 2263** will be rolled back automatically. 2264** 2265** ^The sqlite3_interrupt(D) call is in effect until all currently running 2266** SQL statements on [database connection] D complete. ^Any new SQL statements 2267** that are started after the sqlite3_interrupt() call and before the 2268** running statements reaches zero are interrupted as if they had been 2269** running prior to the sqlite3_interrupt() call. ^New SQL statements 2270** that are started after the running statement count reaches zero are 2271** not effected by the sqlite3_interrupt(). 2272** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2273** SQL statements is a no-op and has no effect on SQL statements 2274** that are started after the sqlite3_interrupt() call returns. 2275*/ 2276void sqlite3_interrupt(sqlite3*); 2277 2278/* 2279** CAPI3REF: Determine If An SQL Statement Is Complete 2280** 2281** These routines are useful during command-line input to determine if the 2282** currently entered text seems to form a complete SQL statement or 2283** if additional input is needed before sending the text into 2284** SQLite for parsing. ^These routines return 1 if the input string 2285** appears to be a complete SQL statement. ^A statement is judged to be 2286** complete if it ends with a semicolon token and is not a prefix of a 2287** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2288** string literals or quoted identifier names or comments are not 2289** independent tokens (they are part of the token in which they are 2290** embedded) and thus do not count as a statement terminator. ^Whitespace 2291** and comments that follow the final semicolon are ignored. 2292** 2293** ^These routines return 0 if the statement is incomplete. ^If a 2294** memory allocation fails, then SQLITE_NOMEM is returned. 2295** 2296** ^These routines do not parse the SQL statements thus 2297** will not detect syntactically incorrect SQL. 2298** 2299** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2300** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2301** automatically by sqlite3_complete16(). If that initialization fails, 2302** then the return value from sqlite3_complete16() will be non-zero 2303** regardless of whether or not the input SQL is complete.)^ 2304** 2305** The input to [sqlite3_complete()] must be a zero-terminated 2306** UTF-8 string. 2307** 2308** The input to [sqlite3_complete16()] must be a zero-terminated 2309** UTF-16 string in native byte order. 2310*/ 2311int sqlite3_complete(const char *sql); 2312int sqlite3_complete16(const void *sql); 2313 2314/* 2315** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2316** KEYWORDS: {busy-handler callback} {busy handler} 2317** METHOD: sqlite3 2318** 2319** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2320** that might be invoked with argument P whenever 2321** an attempt is made to access a database table associated with 2322** [database connection] D when another thread 2323** or process has the table locked. 2324** The sqlite3_busy_handler() interface is used to implement 2325** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2326** 2327** ^If the busy callback is NULL, then [SQLITE_BUSY] 2328** is returned immediately upon encountering the lock. ^If the busy callback 2329** is not NULL, then the callback might be invoked with two arguments. 2330** 2331** ^The first argument to the busy handler is a copy of the void* pointer which 2332** is the third argument to sqlite3_busy_handler(). ^The second argument to 2333** the busy handler callback is the number of times that the busy handler has 2334** been invoked previously for the same locking event. ^If the 2335** busy callback returns 0, then no additional attempts are made to 2336** access the database and [SQLITE_BUSY] is returned 2337** to the application. 2338** ^If the callback returns non-zero, then another attempt 2339** is made to access the database and the cycle repeats. 2340** 2341** The presence of a busy handler does not guarantee that it will be invoked 2342** when there is lock contention. ^If SQLite determines that invoking the busy 2343** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2344** to the application instead of invoking the 2345** busy handler. 2346** Consider a scenario where one process is holding a read lock that 2347** it is trying to promote to a reserved lock and 2348** a second process is holding a reserved lock that it is trying 2349** to promote to an exclusive lock. The first process cannot proceed 2350** because it is blocked by the second and the second process cannot 2351** proceed because it is blocked by the first. If both processes 2352** invoke the busy handlers, neither will make any progress. Therefore, 2353** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2354** will induce the first process to release its read lock and allow 2355** the second process to proceed. 2356** 2357** ^The default busy callback is NULL. 2358** 2359** ^(There can only be a single busy handler defined for each 2360** [database connection]. Setting a new busy handler clears any 2361** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2362** or evaluating [PRAGMA busy_timeout=N] will change the 2363** busy handler and thus clear any previously set busy handler. 2364** 2365** The busy callback should not take any actions which modify the 2366** database connection that invoked the busy handler. In other words, 2367** the busy handler is not reentrant. Any such actions 2368** result in undefined behavior. 2369** 2370** A busy handler must not close the database connection 2371** or [prepared statement] that invoked the busy handler. 2372*/ 2373int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2374 2375/* 2376** CAPI3REF: Set A Busy Timeout 2377** METHOD: sqlite3 2378** 2379** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2380** for a specified amount of time when a table is locked. ^The handler 2381** will sleep multiple times until at least "ms" milliseconds of sleeping 2382** have accumulated. ^After at least "ms" milliseconds of sleeping, 2383** the handler returns 0 which causes [sqlite3_step()] to return 2384** [SQLITE_BUSY]. 2385** 2386** ^Calling this routine with an argument less than or equal to zero 2387** turns off all busy handlers. 2388** 2389** ^(There can only be a single busy handler for a particular 2390** [database connection] at any given moment. If another busy handler 2391** was defined (using [sqlite3_busy_handler()]) prior to calling 2392** this routine, that other busy handler is cleared.)^ 2393** 2394** See also: [PRAGMA busy_timeout] 2395*/ 2396int sqlite3_busy_timeout(sqlite3*, int ms); 2397 2398/* 2399** CAPI3REF: Convenience Routines For Running Queries 2400** METHOD: sqlite3 2401** 2402** This is a legacy interface that is preserved for backwards compatibility. 2403** Use of this interface is not recommended. 2404** 2405** Definition: A <b>result table</b> is memory data structure created by the 2406** [sqlite3_get_table()] interface. A result table records the 2407** complete query results from one or more queries. 2408** 2409** The table conceptually has a number of rows and columns. But 2410** these numbers are not part of the result table itself. These 2411** numbers are obtained separately. Let N be the number of rows 2412** and M be the number of columns. 2413** 2414** A result table is an array of pointers to zero-terminated UTF-8 strings. 2415** There are (N+1)*M elements in the array. The first M pointers point 2416** to zero-terminated strings that contain the names of the columns. 2417** The remaining entries all point to query results. NULL values result 2418** in NULL pointers. All other values are in their UTF-8 zero-terminated 2419** string representation as returned by [sqlite3_column_text()]. 2420** 2421** A result table might consist of one or more memory allocations. 2422** It is not safe to pass a result table directly to [sqlite3_free()]. 2423** A result table should be deallocated using [sqlite3_free_table()]. 2424** 2425** ^(As an example of the result table format, suppose a query result 2426** is as follows: 2427** 2428** <blockquote><pre> 2429** Name | Age 2430** ----------------------- 2431** Alice | 43 2432** Bob | 28 2433** Cindy | 21 2434** </pre></blockquote> 2435** 2436** There are two column (M==2) and three rows (N==3). Thus the 2437** result table has 8 entries. Suppose the result table is stored 2438** in an array names azResult. Then azResult holds this content: 2439** 2440** <blockquote><pre> 2441** azResult[0] = "Name"; 2442** azResult[1] = "Age"; 2443** azResult[2] = "Alice"; 2444** azResult[3] = "43"; 2445** azResult[4] = "Bob"; 2446** azResult[5] = "28"; 2447** azResult[6] = "Cindy"; 2448** azResult[7] = "21"; 2449** </pre></blockquote>)^ 2450** 2451** ^The sqlite3_get_table() function evaluates one or more 2452** semicolon-separated SQL statements in the zero-terminated UTF-8 2453** string of its 2nd parameter and returns a result table to the 2454** pointer given in its 3rd parameter. 2455** 2456** After the application has finished with the result from sqlite3_get_table(), 2457** it must pass the result table pointer to sqlite3_free_table() in order to 2458** release the memory that was malloced. Because of the way the 2459** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2460** function must not try to call [sqlite3_free()] directly. Only 2461** [sqlite3_free_table()] is able to release the memory properly and safely. 2462** 2463** The sqlite3_get_table() interface is implemented as a wrapper around 2464** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2465** to any internal data structures of SQLite. It uses only the public 2466** interface defined here. As a consequence, errors that occur in the 2467** wrapper layer outside of the internal [sqlite3_exec()] call are not 2468** reflected in subsequent calls to [sqlite3_errcode()] or 2469** [sqlite3_errmsg()]. 2470*/ 2471int sqlite3_get_table( 2472 sqlite3 *db, /* An open database */ 2473 const char *zSql, /* SQL to be evaluated */ 2474 char ***pazResult, /* Results of the query */ 2475 int *pnRow, /* Number of result rows written here */ 2476 int *pnColumn, /* Number of result columns written here */ 2477 char **pzErrmsg /* Error msg written here */ 2478); 2479void sqlite3_free_table(char **result); 2480 2481/* 2482** CAPI3REF: Formatted String Printing Functions 2483** 2484** These routines are work-alikes of the "printf()" family of functions 2485** from the standard C library. 2486** These routines understand most of the common K&R formatting options, 2487** plus some additional non-standard formats, detailed below. 2488** Note that some of the more obscure formatting options from recent 2489** C-library standards are omitted from this implementation. 2490** 2491** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2492** results into memory obtained from [sqlite3_malloc()]. 2493** The strings returned by these two routines should be 2494** released by [sqlite3_free()]. ^Both routines return a 2495** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2496** memory to hold the resulting string. 2497** 2498** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2499** the standard C library. The result is written into the 2500** buffer supplied as the second parameter whose size is given by 2501** the first parameter. Note that the order of the 2502** first two parameters is reversed from snprintf().)^ This is an 2503** historical accident that cannot be fixed without breaking 2504** backwards compatibility. ^(Note also that sqlite3_snprintf() 2505** returns a pointer to its buffer instead of the number of 2506** characters actually written into the buffer.)^ We admit that 2507** the number of characters written would be a more useful return 2508** value but we cannot change the implementation of sqlite3_snprintf() 2509** now without breaking compatibility. 2510** 2511** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2512** guarantees that the buffer is always zero-terminated. ^The first 2513** parameter "n" is the total size of the buffer, including space for 2514** the zero terminator. So the longest string that can be completely 2515** written will be n-1 characters. 2516** 2517** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2518** 2519** These routines all implement some additional formatting 2520** options that are useful for constructing SQL statements. 2521** All of the usual printf() formatting options apply. In addition, there 2522** is are "%q", "%Q", "%w" and "%z" options. 2523** 2524** ^(The %q option works like %s in that it substitutes a nul-terminated 2525** string from the argument list. But %q also doubles every '\'' character. 2526** %q is designed for use inside a string literal.)^ By doubling each '\'' 2527** character it escapes that character and allows it to be inserted into 2528** the string. 2529** 2530** For example, assume the string variable zText contains text as follows: 2531** 2532** <blockquote><pre> 2533** char *zText = "It's a happy day!"; 2534** </pre></blockquote> 2535** 2536** One can use this text in an SQL statement as follows: 2537** 2538** <blockquote><pre> 2539** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2540** sqlite3_exec(db, zSQL, 0, 0, 0); 2541** sqlite3_free(zSQL); 2542** </pre></blockquote> 2543** 2544** Because the %q format string is used, the '\'' character in zText 2545** is escaped and the SQL generated is as follows: 2546** 2547** <blockquote><pre> 2548** INSERT INTO table1 VALUES('It''s a happy day!') 2549** </pre></blockquote> 2550** 2551** This is correct. Had we used %s instead of %q, the generated SQL 2552** would have looked like this: 2553** 2554** <blockquote><pre> 2555** INSERT INTO table1 VALUES('It's a happy day!'); 2556** </pre></blockquote> 2557** 2558** This second example is an SQL syntax error. As a general rule you should 2559** always use %q instead of %s when inserting text into a string literal. 2560** 2561** ^(The %Q option works like %q except it also adds single quotes around 2562** the outside of the total string. Additionally, if the parameter in the 2563** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2564** single quotes).)^ So, for example, one could say: 2565** 2566** <blockquote><pre> 2567** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2568** sqlite3_exec(db, zSQL, 0, 0, 0); 2569** sqlite3_free(zSQL); 2570** </pre></blockquote> 2571** 2572** The code above will render a correct SQL statement in the zSQL 2573** variable even if the zText variable is a NULL pointer. 2574** 2575** ^(The "%w" formatting option is like "%q" except that it expects to 2576** be contained within double-quotes instead of single quotes, and it 2577** escapes the double-quote character instead of the single-quote 2578** character.)^ The "%w" formatting option is intended for safely inserting 2579** table and column names into a constructed SQL statement. 2580** 2581** ^(The "%z" formatting option works like "%s" but with the 2582** addition that after the string has been read and copied into 2583** the result, [sqlite3_free()] is called on the input string.)^ 2584*/ 2585char *sqlite3_mprintf(const char*,...); 2586char *sqlite3_vmprintf(const char*, va_list); 2587char *sqlite3_snprintf(int,char*,const char*, ...); 2588char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2589 2590/* 2591** CAPI3REF: Memory Allocation Subsystem 2592** 2593** The SQLite core uses these three routines for all of its own 2594** internal memory allocation needs. "Core" in the previous sentence 2595** does not include operating-system specific VFS implementation. The 2596** Windows VFS uses native malloc() and free() for some operations. 2597** 2598** ^The sqlite3_malloc() routine returns a pointer to a block 2599** of memory at least N bytes in length, where N is the parameter. 2600** ^If sqlite3_malloc() is unable to obtain sufficient free 2601** memory, it returns a NULL pointer. ^If the parameter N to 2602** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2603** a NULL pointer. 2604** 2605** ^The sqlite3_malloc64(N) routine works just like 2606** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2607** of a signed 32-bit integer. 2608** 2609** ^Calling sqlite3_free() with a pointer previously returned 2610** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2611** that it might be reused. ^The sqlite3_free() routine is 2612** a no-op if is called with a NULL pointer. Passing a NULL pointer 2613** to sqlite3_free() is harmless. After being freed, memory 2614** should neither be read nor written. Even reading previously freed 2615** memory might result in a segmentation fault or other severe error. 2616** Memory corruption, a segmentation fault, or other severe error 2617** might result if sqlite3_free() is called with a non-NULL pointer that 2618** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2619** 2620** ^The sqlite3_realloc(X,N) interface attempts to resize a 2621** prior memory allocation X to be at least N bytes. 2622** ^If the X parameter to sqlite3_realloc(X,N) 2623** is a NULL pointer then its behavior is identical to calling 2624** sqlite3_malloc(N). 2625** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2626** negative then the behavior is exactly the same as calling 2627** sqlite3_free(X). 2628** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2629** of at least N bytes in size or NULL if insufficient memory is available. 2630** ^If M is the size of the prior allocation, then min(N,M) bytes 2631** of the prior allocation are copied into the beginning of buffer returned 2632** by sqlite3_realloc(X,N) and the prior allocation is freed. 2633** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2634** prior allocation is not freed. 2635** 2636** ^The sqlite3_realloc64(X,N) interfaces works the same as 2637** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2638** of a 32-bit signed integer. 2639** 2640** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2641** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2642** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2643** ^The value returned by sqlite3_msize(X) might be larger than the number 2644** of bytes requested when X was allocated. ^If X is a NULL pointer then 2645** sqlite3_msize(X) returns zero. If X points to something that is not 2646** the beginning of memory allocation, or if it points to a formerly 2647** valid memory allocation that has now been freed, then the behavior 2648** of sqlite3_msize(X) is undefined and possibly harmful. 2649** 2650** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2651** sqlite3_malloc64(), and sqlite3_realloc64() 2652** is always aligned to at least an 8 byte boundary, or to a 2653** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2654** option is used. 2655** 2656** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2657** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2658** implementation of these routines to be omitted. That capability 2659** is no longer provided. Only built-in memory allocators can be used. 2660** 2661** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2662** the system malloc() and free() directly when converting 2663** filenames between the UTF-8 encoding used by SQLite 2664** and whatever filename encoding is used by the particular Windows 2665** installation. Memory allocation errors were detected, but 2666** they were reported back as [SQLITE_CANTOPEN] or 2667** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2668** 2669** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2670** must be either NULL or else pointers obtained from a prior 2671** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2672** not yet been released. 2673** 2674** The application must not read or write any part of 2675** a block of memory after it has been released using 2676** [sqlite3_free()] or [sqlite3_realloc()]. 2677*/ 2678void *sqlite3_malloc(int); 2679void *sqlite3_malloc64(sqlite3_uint64); 2680void *sqlite3_realloc(void*, int); 2681void *sqlite3_realloc64(void*, sqlite3_uint64); 2682void sqlite3_free(void*); 2683sqlite3_uint64 sqlite3_msize(void*); 2684 2685/* 2686** CAPI3REF: Memory Allocator Statistics 2687** 2688** SQLite provides these two interfaces for reporting on the status 2689** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2690** routines, which form the built-in memory allocation subsystem. 2691** 2692** ^The [sqlite3_memory_used()] routine returns the number of bytes 2693** of memory currently outstanding (malloced but not freed). 2694** ^The [sqlite3_memory_highwater()] routine returns the maximum 2695** value of [sqlite3_memory_used()] since the high-water mark 2696** was last reset. ^The values returned by [sqlite3_memory_used()] and 2697** [sqlite3_memory_highwater()] include any overhead 2698** added by SQLite in its implementation of [sqlite3_malloc()], 2699** but not overhead added by the any underlying system library 2700** routines that [sqlite3_malloc()] may call. 2701** 2702** ^The memory high-water mark is reset to the current value of 2703** [sqlite3_memory_used()] if and only if the parameter to 2704** [sqlite3_memory_highwater()] is true. ^The value returned 2705** by [sqlite3_memory_highwater(1)] is the high-water mark 2706** prior to the reset. 2707*/ 2708sqlite3_int64 sqlite3_memory_used(void); 2709sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2710 2711/* 2712** CAPI3REF: Pseudo-Random Number Generator 2713** 2714** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2715** select random [ROWID | ROWIDs] when inserting new records into a table that 2716** already uses the largest possible [ROWID]. The PRNG is also used for 2717** the build-in random() and randomblob() SQL functions. This interface allows 2718** applications to access the same PRNG for other purposes. 2719** 2720** ^A call to this routine stores N bytes of randomness into buffer P. 2721** ^The P parameter can be a NULL pointer. 2722** 2723** ^If this routine has not been previously called or if the previous 2724** call had N less than one or a NULL pointer for P, then the PRNG is 2725** seeded using randomness obtained from the xRandomness method of 2726** the default [sqlite3_vfs] object. 2727** ^If the previous call to this routine had an N of 1 or more and a 2728** non-NULL P then the pseudo-randomness is generated 2729** internally and without recourse to the [sqlite3_vfs] xRandomness 2730** method. 2731*/ 2732void sqlite3_randomness(int N, void *P); 2733 2734/* 2735** CAPI3REF: Compile-Time Authorization Callbacks 2736** METHOD: sqlite3 2737** KEYWORDS: {authorizer callback} 2738** 2739** ^This routine registers an authorizer callback with a particular 2740** [database connection], supplied in the first argument. 2741** ^The authorizer callback is invoked as SQL statements are being compiled 2742** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2743** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2744** and [sqlite3_prepare16_v3()]. ^At various 2745** points during the compilation process, as logic is being created 2746** to perform various actions, the authorizer callback is invoked to 2747** see if those actions are allowed. ^The authorizer callback should 2748** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2749** specific action but allow the SQL statement to continue to be 2750** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2751** rejected with an error. ^If the authorizer callback returns 2752** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2753** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2754** the authorizer will fail with an error message. 2755** 2756** When the callback returns [SQLITE_OK], that means the operation 2757** requested is ok. ^When the callback returns [SQLITE_DENY], the 2758** [sqlite3_prepare_v2()] or equivalent call that triggered the 2759** authorizer will fail with an error message explaining that 2760** access is denied. 2761** 2762** ^The first parameter to the authorizer callback is a copy of the third 2763** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2764** to the callback is an integer [SQLITE_COPY | action code] that specifies 2765** the particular action to be authorized. ^The third through sixth parameters 2766** to the callback are either NULL pointers or zero-terminated strings 2767** that contain additional details about the action to be authorized. 2768** Applications must always be prepared to encounter a NULL pointer in any 2769** of the third through the sixth parameters of the authorization callback. 2770** 2771** ^If the action code is [SQLITE_READ] 2772** and the callback returns [SQLITE_IGNORE] then the 2773** [prepared statement] statement is constructed to substitute 2774** a NULL value in place of the table column that would have 2775** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2776** return can be used to deny an untrusted user access to individual 2777** columns of a table. 2778** ^When a table is referenced by a [SELECT] but no column values are 2779** extracted from that table (for example in a query like 2780** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2781** is invoked once for that table with a column name that is an empty string. 2782** ^If the action code is [SQLITE_DELETE] and the callback returns 2783** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2784** [truncate optimization] is disabled and all rows are deleted individually. 2785** 2786** An authorizer is used when [sqlite3_prepare | preparing] 2787** SQL statements from an untrusted source, to ensure that the SQL statements 2788** do not try to access data they are not allowed to see, or that they do not 2789** try to execute malicious statements that damage the database. For 2790** example, an application may allow a user to enter arbitrary 2791** SQL queries for evaluation by a database. But the application does 2792** not want the user to be able to make arbitrary changes to the 2793** database. An authorizer could then be put in place while the 2794** user-entered SQL is being [sqlite3_prepare | prepared] that 2795** disallows everything except [SELECT] statements. 2796** 2797** Applications that need to process SQL from untrusted sources 2798** might also consider lowering resource limits using [sqlite3_limit()] 2799** and limiting database size using the [max_page_count] [PRAGMA] 2800** in addition to using an authorizer. 2801** 2802** ^(Only a single authorizer can be in place on a database connection 2803** at a time. Each call to sqlite3_set_authorizer overrides the 2804** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2805** The authorizer is disabled by default. 2806** 2807** The authorizer callback must not do anything that will modify 2808** the database connection that invoked the authorizer callback. 2809** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2810** database connections for the meaning of "modify" in this paragraph. 2811** 2812** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2813** statement might be re-prepared during [sqlite3_step()] due to a 2814** schema change. Hence, the application should ensure that the 2815** correct authorizer callback remains in place during the [sqlite3_step()]. 2816** 2817** ^Note that the authorizer callback is invoked only during 2818** [sqlite3_prepare()] or its variants. Authorization is not 2819** performed during statement evaluation in [sqlite3_step()], unless 2820** as stated in the previous paragraph, sqlite3_step() invokes 2821** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2822*/ 2823int sqlite3_set_authorizer( 2824 sqlite3*, 2825 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2826 void *pUserData 2827); 2828 2829/* 2830** CAPI3REF: Authorizer Return Codes 2831** 2832** The [sqlite3_set_authorizer | authorizer callback function] must 2833** return either [SQLITE_OK] or one of these two constants in order 2834** to signal SQLite whether or not the action is permitted. See the 2835** [sqlite3_set_authorizer | authorizer documentation] for additional 2836** information. 2837** 2838** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2839** returned from the [sqlite3_vtab_on_conflict()] interface. 2840*/ 2841#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2842#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2843 2844/* 2845** CAPI3REF: Authorizer Action Codes 2846** 2847** The [sqlite3_set_authorizer()] interface registers a callback function 2848** that is invoked to authorize certain SQL statement actions. The 2849** second parameter to the callback is an integer code that specifies 2850** what action is being authorized. These are the integer action codes that 2851** the authorizer callback may be passed. 2852** 2853** These action code values signify what kind of operation is to be 2854** authorized. The 3rd and 4th parameters to the authorization 2855** callback function will be parameters or NULL depending on which of these 2856** codes is used as the second parameter. ^(The 5th parameter to the 2857** authorizer callback is the name of the database ("main", "temp", 2858** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2859** is the name of the inner-most trigger or view that is responsible for 2860** the access attempt or NULL if this access attempt is directly from 2861** top-level SQL code. 2862*/ 2863/******************************************* 3rd ************ 4th ***********/ 2864#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2865#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2866#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2867#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2868#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2869#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2870#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2871#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2872#define SQLITE_DELETE 9 /* Table Name NULL */ 2873#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2874#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2875#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2876#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2877#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2878#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2879#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2880#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2881#define SQLITE_INSERT 18 /* Table Name NULL */ 2882#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2883#define SQLITE_READ 20 /* Table Name Column Name */ 2884#define SQLITE_SELECT 21 /* NULL NULL */ 2885#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2886#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2887#define SQLITE_ATTACH 24 /* Filename NULL */ 2888#define SQLITE_DETACH 25 /* Database Name NULL */ 2889#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2890#define SQLITE_REINDEX 27 /* Index Name NULL */ 2891#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2892#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2893#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2894#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2895#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2896#define SQLITE_COPY 0 /* No longer used */ 2897#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2898 2899/* 2900** CAPI3REF: Tracing And Profiling Functions 2901** METHOD: sqlite3 2902** 2903** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2904** instead of the routines described here. 2905** 2906** These routines register callback functions that can be used for 2907** tracing and profiling the execution of SQL statements. 2908** 2909** ^The callback function registered by sqlite3_trace() is invoked at 2910** various times when an SQL statement is being run by [sqlite3_step()]. 2911** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2912** SQL statement text as the statement first begins executing. 2913** ^(Additional sqlite3_trace() callbacks might occur 2914** as each triggered subprogram is entered. The callbacks for triggers 2915** contain a UTF-8 SQL comment that identifies the trigger.)^ 2916** 2917** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2918** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2919** 2920** ^The callback function registered by sqlite3_profile() is invoked 2921** as each SQL statement finishes. ^The profile callback contains 2922** the original statement text and an estimate of wall-clock time 2923** of how long that statement took to run. ^The profile callback 2924** time is in units of nanoseconds, however the current implementation 2925** is only capable of millisecond resolution so the six least significant 2926** digits in the time are meaningless. Future versions of SQLite 2927** might provide greater resolution on the profiler callback. The 2928** sqlite3_profile() function is considered experimental and is 2929** subject to change in future versions of SQLite. 2930*/ 2931SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2932 void(*xTrace)(void*,const char*), void*); 2933SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2934 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2935 2936/* 2937** CAPI3REF: SQL Trace Event Codes 2938** KEYWORDS: SQLITE_TRACE 2939** 2940** These constants identify classes of events that can be monitored 2941** using the [sqlite3_trace_v2()] tracing logic. The third argument 2942** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2943** the following constants. ^The first argument to the trace callback 2944** is one of the following constants. 2945** 2946** New tracing constants may be added in future releases. 2947** 2948** ^A trace callback has four arguments: xCallback(T,C,P,X). 2949** ^The T argument is one of the integer type codes above. 2950** ^The C argument is a copy of the context pointer passed in as the 2951** fourth argument to [sqlite3_trace_v2()]. 2952** The P and X arguments are pointers whose meanings depend on T. 2953** 2954** <dl> 2955** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2956** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2957** first begins running and possibly at other times during the 2958** execution of the prepared statement, such as at the start of each 2959** trigger subprogram. ^The P argument is a pointer to the 2960** [prepared statement]. ^The X argument is a pointer to a string which 2961** is the unexpanded SQL text of the prepared statement or an SQL comment 2962** that indicates the invocation of a trigger. ^The callback can compute 2963** the same text that would have been returned by the legacy [sqlite3_trace()] 2964** interface by using the X argument when X begins with "--" and invoking 2965** [sqlite3_expanded_sql(P)] otherwise. 2966** 2967** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2968** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2969** information as is provided by the [sqlite3_profile()] callback. 2970** ^The P argument is a pointer to the [prepared statement] and the 2971** X argument points to a 64-bit integer which is the estimated of 2972** the number of nanosecond that the prepared statement took to run. 2973** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2974** 2975** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2976** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2977** statement generates a single row of result. 2978** ^The P argument is a pointer to the [prepared statement] and the 2979** X argument is unused. 2980** 2981** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2982** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2983** connection closes. 2984** ^The P argument is a pointer to the [database connection] object 2985** and the X argument is unused. 2986** </dl> 2987*/ 2988#define SQLITE_TRACE_STMT 0x01 2989#define SQLITE_TRACE_PROFILE 0x02 2990#define SQLITE_TRACE_ROW 0x04 2991#define SQLITE_TRACE_CLOSE 0x08 2992 2993/* 2994** CAPI3REF: SQL Trace Hook 2995** METHOD: sqlite3 2996** 2997** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2998** function X against [database connection] D, using property mask M 2999** and context pointer P. ^If the X callback is 3000** NULL or if the M mask is zero, then tracing is disabled. The 3001** M argument should be the bitwise OR-ed combination of 3002** zero or more [SQLITE_TRACE] constants. 3003** 3004** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3005** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3006** 3007** ^The X callback is invoked whenever any of the events identified by 3008** mask M occur. ^The integer return value from the callback is currently 3009** ignored, though this may change in future releases. Callback 3010** implementations should return zero to ensure future compatibility. 3011** 3012** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3013** ^The T argument is one of the [SQLITE_TRACE] 3014** constants to indicate why the callback was invoked. 3015** ^The C argument is a copy of the context pointer. 3016** The P and X arguments are pointers whose meanings depend on T. 3017** 3018** The sqlite3_trace_v2() interface is intended to replace the legacy 3019** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3020** are deprecated. 3021*/ 3022int sqlite3_trace_v2( 3023 sqlite3*, 3024 unsigned uMask, 3025 int(*xCallback)(unsigned,void*,void*,void*), 3026 void *pCtx 3027); 3028 3029/* 3030** CAPI3REF: Query Progress Callbacks 3031** METHOD: sqlite3 3032** 3033** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3034** function X to be invoked periodically during long running calls to 3035** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3036** database connection D. An example use for this 3037** interface is to keep a GUI updated during a large query. 3038** 3039** ^The parameter P is passed through as the only parameter to the 3040** callback function X. ^The parameter N is the approximate number of 3041** [virtual machine instructions] that are evaluated between successive 3042** invocations of the callback X. ^If N is less than one then the progress 3043** handler is disabled. 3044** 3045** ^Only a single progress handler may be defined at one time per 3046** [database connection]; setting a new progress handler cancels the 3047** old one. ^Setting parameter X to NULL disables the progress handler. 3048** ^The progress handler is also disabled by setting N to a value less 3049** than 1. 3050** 3051** ^If the progress callback returns non-zero, the operation is 3052** interrupted. This feature can be used to implement a 3053** "Cancel" button on a GUI progress dialog box. 3054** 3055** The progress handler callback must not do anything that will modify 3056** the database connection that invoked the progress handler. 3057** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3058** database connections for the meaning of "modify" in this paragraph. 3059** 3060*/ 3061void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3062 3063/* 3064** CAPI3REF: Opening A New Database Connection 3065** CONSTRUCTOR: sqlite3 3066** 3067** ^These routines open an SQLite database file as specified by the 3068** filename argument. ^The filename argument is interpreted as UTF-8 for 3069** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3070** order for sqlite3_open16(). ^(A [database connection] handle is usually 3071** returned in *ppDb, even if an error occurs. The only exception is that 3072** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3073** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3074** object.)^ ^(If the database is opened (and/or created) successfully, then 3075** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3076** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3077** an English language description of the error following a failure of any 3078** of the sqlite3_open() routines. 3079** 3080** ^The default encoding will be UTF-8 for databases created using 3081** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3082** created using sqlite3_open16() will be UTF-16 in the native byte order. 3083** 3084** Whether or not an error occurs when it is opened, resources 3085** associated with the [database connection] handle should be released by 3086** passing it to [sqlite3_close()] when it is no longer required. 3087** 3088** The sqlite3_open_v2() interface works like sqlite3_open() 3089** except that it accepts two additional parameters for additional control 3090** over the new database connection. ^(The flags parameter to 3091** sqlite3_open_v2() can take one of 3092** the following three values, optionally combined with the 3093** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3094** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3095** 3096** <dl> 3097** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3098** <dd>The database is opened in read-only mode. If the database does not 3099** already exist, an error is returned.</dd>)^ 3100** 3101** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3102** <dd>The database is opened for reading and writing if possible, or reading 3103** only if the file is write protected by the operating system. In either 3104** case the database must already exist, otherwise an error is returned.</dd>)^ 3105** 3106** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3107** <dd>The database is opened for reading and writing, and is created if 3108** it does not already exist. This is the behavior that is always used for 3109** sqlite3_open() and sqlite3_open16().</dd>)^ 3110** </dl> 3111** 3112** If the 3rd parameter to sqlite3_open_v2() is not one of the 3113** combinations shown above optionally combined with other 3114** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3115** then the behavior is undefined. 3116** 3117** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3118** opens in the multi-thread [threading mode] as long as the single-thread 3119** mode has not been set at compile-time or start-time. ^If the 3120** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3121** in the serialized [threading mode] unless single-thread was 3122** previously selected at compile-time or start-time. 3123** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3124** eligible to use [shared cache mode], regardless of whether or not shared 3125** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3126** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3127** participate in [shared cache mode] even if it is enabled. 3128** 3129** ^The fourth parameter to sqlite3_open_v2() is the name of the 3130** [sqlite3_vfs] object that defines the operating system interface that 3131** the new database connection should use. ^If the fourth parameter is 3132** a NULL pointer then the default [sqlite3_vfs] object is used. 3133** 3134** ^If the filename is ":memory:", then a private, temporary in-memory database 3135** is created for the connection. ^This in-memory database will vanish when 3136** the database connection is closed. Future versions of SQLite might 3137** make use of additional special filenames that begin with the ":" character. 3138** It is recommended that when a database filename actually does begin with 3139** a ":" character you should prefix the filename with a pathname such as 3140** "./" to avoid ambiguity. 3141** 3142** ^If the filename is an empty string, then a private, temporary 3143** on-disk database will be created. ^This private database will be 3144** automatically deleted as soon as the database connection is closed. 3145** 3146** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3147** 3148** ^If [URI filename] interpretation is enabled, and the filename argument 3149** begins with "file:", then the filename is interpreted as a URI. ^URI 3150** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3151** set in the third argument to sqlite3_open_v2(), or if it has 3152** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3153** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3154** URI filename interpretation is turned off 3155** by default, but future releases of SQLite might enable URI filename 3156** interpretation by default. See "[URI filenames]" for additional 3157** information. 3158** 3159** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3160** authority, then it must be either an empty string or the string 3161** "localhost". ^If the authority is not an empty string or "localhost", an 3162** error is returned to the caller. ^The fragment component of a URI, if 3163** present, is ignored. 3164** 3165** ^SQLite uses the path component of the URI as the name of the disk file 3166** which contains the database. ^If the path begins with a '/' character, 3167** then it is interpreted as an absolute path. ^If the path does not begin 3168** with a '/' (meaning that the authority section is omitted from the URI) 3169** then the path is interpreted as a relative path. 3170** ^(On windows, the first component of an absolute path 3171** is a drive specification (e.g. "C:").)^ 3172** 3173** [[core URI query parameters]] 3174** The query component of a URI may contain parameters that are interpreted 3175** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3176** SQLite and its built-in [VFSes] interpret the 3177** following query parameters: 3178** 3179** <ul> 3180** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3181** a VFS object that provides the operating system interface that should 3182** be used to access the database file on disk. ^If this option is set to 3183** an empty string the default VFS object is used. ^Specifying an unknown 3184** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3185** present, then the VFS specified by the option takes precedence over 3186** the value passed as the fourth parameter to sqlite3_open_v2(). 3187** 3188** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3189** "rwc", or "memory". Attempting to set it to any other value is 3190** an error)^. 3191** ^If "ro" is specified, then the database is opened for read-only 3192** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3193** third argument to sqlite3_open_v2(). ^If the mode option is set to 3194** "rw", then the database is opened for read-write (but not create) 3195** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3196** been set. ^Value "rwc" is equivalent to setting both 3197** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3198** set to "memory" then a pure [in-memory database] that never reads 3199** or writes from disk is used. ^It is an error to specify a value for 3200** the mode parameter that is less restrictive than that specified by 3201** the flags passed in the third parameter to sqlite3_open_v2(). 3202** 3203** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3204** "private". ^Setting it to "shared" is equivalent to setting the 3205** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3206** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3207** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3208** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3209** a URI filename, its value overrides any behavior requested by setting 3210** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3211** 3212** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3213** [powersafe overwrite] property does or does not apply to the 3214** storage media on which the database file resides. 3215** 3216** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3217** which if set disables file locking in rollback journal modes. This 3218** is useful for accessing a database on a filesystem that does not 3219** support locking. Caution: Database corruption might result if two 3220** or more processes write to the same database and any one of those 3221** processes uses nolock=1. 3222** 3223** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3224** parameter that indicates that the database file is stored on 3225** read-only media. ^When immutable is set, SQLite assumes that the 3226** database file cannot be changed, even by a process with higher 3227** privilege, and so the database is opened read-only and all locking 3228** and change detection is disabled. Caution: Setting the immutable 3229** property on a database file that does in fact change can result 3230** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3231** See also: [SQLITE_IOCAP_IMMUTABLE]. 3232** 3233** </ul> 3234** 3235** ^Specifying an unknown parameter in the query component of a URI is not an 3236** error. Future versions of SQLite might understand additional query 3237** parameters. See "[query parameters with special meaning to SQLite]" for 3238** additional information. 3239** 3240** [[URI filename examples]] <h3>URI filename examples</h3> 3241** 3242** <table border="1" align=center cellpadding=5> 3243** <tr><th> URI filenames <th> Results 3244** <tr><td> file:data.db <td> 3245** Open the file "data.db" in the current directory. 3246** <tr><td> file:/home/fred/data.db<br> 3247** file:///home/fred/data.db <br> 3248** file://localhost/home/fred/data.db <br> <td> 3249** Open the database file "/home/fred/data.db". 3250** <tr><td> file://darkstar/home/fred/data.db <td> 3251** An error. "darkstar" is not a recognized authority. 3252** <tr><td style="white-space:nowrap"> 3253** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3254** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3255** C:. Note that the %20 escaping in this example is not strictly 3256** necessary - space characters can be used literally 3257** in URI filenames. 3258** <tr><td> file:data.db?mode=ro&cache=private <td> 3259** Open file "data.db" in the current directory for read-only access. 3260** Regardless of whether or not shared-cache mode is enabled by 3261** default, use a private cache. 3262** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3263** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3264** that uses dot-files in place of posix advisory locking. 3265** <tr><td> file:data.db?mode=readonly <td> 3266** An error. "readonly" is not a valid option for the "mode" parameter. 3267** </table> 3268** 3269** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3270** query components of a URI. A hexadecimal escape sequence consists of a 3271** percent sign - "%" - followed by exactly two hexadecimal digits 3272** specifying an octet value. ^Before the path or query components of a 3273** URI filename are interpreted, they are encoded using UTF-8 and all 3274** hexadecimal escape sequences replaced by a single byte containing the 3275** corresponding octet. If this process generates an invalid UTF-8 encoding, 3276** the results are undefined. 3277** 3278** <b>Note to Windows users:</b> The encoding used for the filename argument 3279** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3280** codepage is currently defined. Filenames containing international 3281** characters must be converted to UTF-8 prior to passing them into 3282** sqlite3_open() or sqlite3_open_v2(). 3283** 3284** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3285** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3286** features that require the use of temporary files may fail. 3287** 3288** See also: [sqlite3_temp_directory] 3289*/ 3290int sqlite3_open( 3291 const char *filename, /* Database filename (UTF-8) */ 3292 sqlite3 **ppDb /* OUT: SQLite db handle */ 3293); 3294int sqlite3_open16( 3295 const void *filename, /* Database filename (UTF-16) */ 3296 sqlite3 **ppDb /* OUT: SQLite db handle */ 3297); 3298int sqlite3_open_v2( 3299 const char *filename, /* Database filename (UTF-8) */ 3300 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3301 int flags, /* Flags */ 3302 const char *zVfs /* Name of VFS module to use */ 3303); 3304 3305/* 3306** CAPI3REF: Obtain Values For URI Parameters 3307** 3308** These are utility routines, useful to VFS implementations, that check 3309** to see if a database file was a URI that contained a specific query 3310** parameter, and if so obtains the value of that query parameter. 3311** 3312** If F is the database filename pointer passed into the xOpen() method of 3313** a VFS implementation when the flags parameter to xOpen() has one or 3314** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3315** P is the name of the query parameter, then 3316** sqlite3_uri_parameter(F,P) returns the value of the P 3317** parameter if it exists or a NULL pointer if P does not appear as a 3318** query parameter on F. If P is a query parameter of F 3319** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3320** a pointer to an empty string. 3321** 3322** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3323** parameter and returns true (1) or false (0) according to the value 3324** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3325** value of query parameter P is one of "yes", "true", or "on" in any 3326** case or if the value begins with a non-zero number. The 3327** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3328** query parameter P is one of "no", "false", or "off" in any case or 3329** if the value begins with a numeric zero. If P is not a query 3330** parameter on F or if the value of P is does not match any of the 3331** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3332** 3333** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3334** 64-bit signed integer and returns that integer, or D if P does not 3335** exist. If the value of P is something other than an integer, then 3336** zero is returned. 3337** 3338** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3339** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3340** is not a database file pathname pointer that SQLite passed into the xOpen 3341** VFS method, then the behavior of this routine is undefined and probably 3342** undesirable. 3343*/ 3344const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3345int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3346sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3347 3348 3349/* 3350** CAPI3REF: Error Codes And Messages 3351** METHOD: sqlite3 3352** 3353** ^If the most recent sqlite3_* API call associated with 3354** [database connection] D failed, then the sqlite3_errcode(D) interface 3355** returns the numeric [result code] or [extended result code] for that 3356** API call. 3357** If the most recent API call was successful, 3358** then the return value from sqlite3_errcode() is undefined. 3359** ^The sqlite3_extended_errcode() 3360** interface is the same except that it always returns the 3361** [extended result code] even when extended result codes are 3362** disabled. 3363** 3364** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3365** text that describes the error, as either UTF-8 or UTF-16 respectively. 3366** ^(Memory to hold the error message string is managed internally. 3367** The application does not need to worry about freeing the result. 3368** However, the error string might be overwritten or deallocated by 3369** subsequent calls to other SQLite interface functions.)^ 3370** 3371** ^The sqlite3_errstr() interface returns the English-language text 3372** that describes the [result code], as UTF-8. 3373** ^(Memory to hold the error message string is managed internally 3374** and must not be freed by the application)^. 3375** 3376** When the serialized [threading mode] is in use, it might be the 3377** case that a second error occurs on a separate thread in between 3378** the time of the first error and the call to these interfaces. 3379** When that happens, the second error will be reported since these 3380** interfaces always report the most recent result. To avoid 3381** this, each thread can obtain exclusive use of the [database connection] D 3382** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3383** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3384** all calls to the interfaces listed here are completed. 3385** 3386** If an interface fails with SQLITE_MISUSE, that means the interface 3387** was invoked incorrectly by the application. In that case, the 3388** error code and message may or may not be set. 3389*/ 3390int sqlite3_errcode(sqlite3 *db); 3391int sqlite3_extended_errcode(sqlite3 *db); 3392const char *sqlite3_errmsg(sqlite3*); 3393const void *sqlite3_errmsg16(sqlite3*); 3394const char *sqlite3_errstr(int); 3395 3396/* 3397** CAPI3REF: Prepared Statement Object 3398** KEYWORDS: {prepared statement} {prepared statements} 3399** 3400** An instance of this object represents a single SQL statement that 3401** has been compiled into binary form and is ready to be evaluated. 3402** 3403** Think of each SQL statement as a separate computer program. The 3404** original SQL text is source code. A prepared statement object 3405** is the compiled object code. All SQL must be converted into a 3406** prepared statement before it can be run. 3407** 3408** The life-cycle of a prepared statement object usually goes like this: 3409** 3410** <ol> 3411** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3412** <li> Bind values to [parameters] using the sqlite3_bind_*() 3413** interfaces. 3414** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3415** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3416** to step 2. Do this zero or more times. 3417** <li> Destroy the object using [sqlite3_finalize()]. 3418** </ol> 3419*/ 3420typedef struct sqlite3_stmt sqlite3_stmt; 3421 3422/* 3423** CAPI3REF: Run-time Limits 3424** METHOD: sqlite3 3425** 3426** ^(This interface allows the size of various constructs to be limited 3427** on a connection by connection basis. The first parameter is the 3428** [database connection] whose limit is to be set or queried. The 3429** second parameter is one of the [limit categories] that define a 3430** class of constructs to be size limited. The third parameter is the 3431** new limit for that construct.)^ 3432** 3433** ^If the new limit is a negative number, the limit is unchanged. 3434** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3435** [limits | hard upper bound] 3436** set at compile-time by a C preprocessor macro called 3437** [limits | SQLITE_MAX_<i>NAME</i>]. 3438** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3439** ^Attempts to increase a limit above its hard upper bound are 3440** silently truncated to the hard upper bound. 3441** 3442** ^Regardless of whether or not the limit was changed, the 3443** [sqlite3_limit()] interface returns the prior value of the limit. 3444** ^Hence, to find the current value of a limit without changing it, 3445** simply invoke this interface with the third parameter set to -1. 3446** 3447** Run-time limits are intended for use in applications that manage 3448** both their own internal database and also databases that are controlled 3449** by untrusted external sources. An example application might be a 3450** web browser that has its own databases for storing history and 3451** separate databases controlled by JavaScript applications downloaded 3452** off the Internet. The internal databases can be given the 3453** large, default limits. Databases managed by external sources can 3454** be given much smaller limits designed to prevent a denial of service 3455** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3456** interface to further control untrusted SQL. The size of the database 3457** created by an untrusted script can be contained using the 3458** [max_page_count] [PRAGMA]. 3459** 3460** New run-time limit categories may be added in future releases. 3461*/ 3462int sqlite3_limit(sqlite3*, int id, int newVal); 3463 3464/* 3465** CAPI3REF: Run-Time Limit Categories 3466** KEYWORDS: {limit category} {*limit categories} 3467** 3468** These constants define various performance limits 3469** that can be lowered at run-time using [sqlite3_limit()]. 3470** The synopsis of the meanings of the various limits is shown below. 3471** Additional information is available at [limits | Limits in SQLite]. 3472** 3473** <dl> 3474** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3475** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3476** 3477** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3478** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3479** 3480** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3481** <dd>The maximum number of columns in a table definition or in the 3482** result set of a [SELECT] or the maximum number of columns in an index 3483** or in an ORDER BY or GROUP BY clause.</dd>)^ 3484** 3485** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3486** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3487** 3488** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3489** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3490** 3491** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3492** <dd>The maximum number of instructions in a virtual machine program 3493** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3494** the equivalent tries to allocate space for more than this many opcodes 3495** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3496** 3497** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3498** <dd>The maximum number of arguments on a function.</dd>)^ 3499** 3500** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3501** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3502** 3503** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3504** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3505** <dd>The maximum length of the pattern argument to the [LIKE] or 3506** [GLOB] operators.</dd>)^ 3507** 3508** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3509** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3510** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3511** 3512** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3513** <dd>The maximum depth of recursion for triggers.</dd>)^ 3514** 3515** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3516** <dd>The maximum number of auxiliary worker threads that a single 3517** [prepared statement] may start.</dd>)^ 3518** </dl> 3519*/ 3520#define SQLITE_LIMIT_LENGTH 0 3521#define SQLITE_LIMIT_SQL_LENGTH 1 3522#define SQLITE_LIMIT_COLUMN 2 3523#define SQLITE_LIMIT_EXPR_DEPTH 3 3524#define SQLITE_LIMIT_COMPOUND_SELECT 4 3525#define SQLITE_LIMIT_VDBE_OP 5 3526#define SQLITE_LIMIT_FUNCTION_ARG 6 3527#define SQLITE_LIMIT_ATTACHED 7 3528#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3529#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3530#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3531#define SQLITE_LIMIT_WORKER_THREADS 11 3532 3533/* 3534** CAPI3REF: Prepare Flags 3535** 3536** These constants define various flags that can be passed into 3537** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3538** [sqlite3_prepare16_v3()] interfaces. 3539** 3540** New flags may be added in future releases of SQLite. 3541** 3542** <dl> 3543** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3544** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3545** that the prepared statement will be retained for a long time and 3546** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3547** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3548** be used just once or at most a few times and then destroyed using 3549** [sqlite3_finalize()] relatively soon. The current implementation acts 3550** on this hint by avoiding the use of [lookaside memory] so as not to 3551** deplete the limited store of lookaside memory. Future versions of 3552** SQLite may act on this hint differently. 3553** </dl> 3554*/ 3555#define SQLITE_PREPARE_PERSISTENT 0x01 3556 3557/* 3558** CAPI3REF: Compiling An SQL Statement 3559** KEYWORDS: {SQL statement compiler} 3560** METHOD: sqlite3 3561** CONSTRUCTOR: sqlite3_stmt 3562** 3563** To execute an SQL statement, it must first be compiled into a byte-code 3564** program using one of these routines. Or, in other words, these routines 3565** are constructors for the [prepared statement] object. 3566** 3567** The preferred routine to use is [sqlite3_prepare_v2()]. The 3568** [sqlite3_prepare()] interface is legacy and should be avoided. 3569** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3570** for special purposes. 3571** 3572** The use of the UTF-8 interfaces is preferred, as SQLite currently 3573** does all parsing using UTF-8. The UTF-16 interfaces are provided 3574** as a convenience. The UTF-16 interfaces work by converting the 3575** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3576** 3577** The first argument, "db", is a [database connection] obtained from a 3578** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3579** [sqlite3_open16()]. The database connection must not have been closed. 3580** 3581** The second argument, "zSql", is the statement to be compiled, encoded 3582** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3583** and sqlite3_prepare_v3() 3584** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3585** and sqlite3_prepare16_v3() use UTF-16. 3586** 3587** ^If the nByte argument is negative, then zSql is read up to the 3588** first zero terminator. ^If nByte is positive, then it is the 3589** number of bytes read from zSql. ^If nByte is zero, then no prepared 3590** statement is generated. 3591** If the caller knows that the supplied string is nul-terminated, then 3592** there is a small performance advantage to passing an nByte parameter that 3593** is the number of bytes in the input string <i>including</i> 3594** the nul-terminator. 3595** 3596** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3597** past the end of the first SQL statement in zSql. These routines only 3598** compile the first statement in zSql, so *pzTail is left pointing to 3599** what remains uncompiled. 3600** 3601** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3602** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3603** to NULL. ^If the input text contains no SQL (if the input is an empty 3604** string or a comment) then *ppStmt is set to NULL. 3605** The calling procedure is responsible for deleting the compiled 3606** SQL statement using [sqlite3_finalize()] after it has finished with it. 3607** ppStmt may not be NULL. 3608** 3609** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3610** otherwise an [error code] is returned. 3611** 3612** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3613** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3614** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3615** are retained for backwards compatibility, but their use is discouraged. 3616** ^In the "vX" interfaces, the prepared statement 3617** that is returned (the [sqlite3_stmt] object) contains a copy of the 3618** original SQL text. This causes the [sqlite3_step()] interface to 3619** behave differently in three ways: 3620** 3621** <ol> 3622** <li> 3623** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3624** always used to do, [sqlite3_step()] will automatically recompile the SQL 3625** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3626** retries will occur before sqlite3_step() gives up and returns an error. 3627** </li> 3628** 3629** <li> 3630** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3631** [error codes] or [extended error codes]. ^The legacy behavior was that 3632** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3633** and the application would have to make a second call to [sqlite3_reset()] 3634** in order to find the underlying cause of the problem. With the "v2" prepare 3635** interfaces, the underlying reason for the error is returned immediately. 3636** </li> 3637** 3638** <li> 3639** ^If the specific value bound to [parameter | host parameter] in the 3640** WHERE clause might influence the choice of query plan for a statement, 3641** then the statement will be automatically recompiled, as if there had been 3642** a schema change, on the first [sqlite3_step()] call following any change 3643** to the [sqlite3_bind_text | bindings] of that [parameter]. 3644** ^The specific value of WHERE-clause [parameter] might influence the 3645** choice of query plan if the parameter is the left-hand side of a [LIKE] 3646** or [GLOB] operator or if the parameter is compared to an indexed column 3647** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3648** </li> 3649** 3650** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3651** the extra prepFlags parameter, which is a bit array consisting of zero or 3652** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3653** sqlite3_prepare_v2() interface works exactly the same as 3654** sqlite3_prepare_v3() with a zero prepFlags parameter. 3655** </ol> 3656*/ 3657int sqlite3_prepare( 3658 sqlite3 *db, /* Database handle */ 3659 const char *zSql, /* SQL statement, UTF-8 encoded */ 3660 int nByte, /* Maximum length of zSql in bytes. */ 3661 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3662 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3663); 3664int sqlite3_prepare_v2( 3665 sqlite3 *db, /* Database handle */ 3666 const char *zSql, /* SQL statement, UTF-8 encoded */ 3667 int nByte, /* Maximum length of zSql in bytes. */ 3668 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3669 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3670); 3671int sqlite3_prepare_v3( 3672 sqlite3 *db, /* Database handle */ 3673 const char *zSql, /* SQL statement, UTF-8 encoded */ 3674 int nByte, /* Maximum length of zSql in bytes. */ 3675 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3676 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3677 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3678); 3679int sqlite3_prepare16( 3680 sqlite3 *db, /* Database handle */ 3681 const void *zSql, /* SQL statement, UTF-16 encoded */ 3682 int nByte, /* Maximum length of zSql in bytes. */ 3683 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3684 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3685); 3686int sqlite3_prepare16_v2( 3687 sqlite3 *db, /* Database handle */ 3688 const void *zSql, /* SQL statement, UTF-16 encoded */ 3689 int nByte, /* Maximum length of zSql in bytes. */ 3690 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3691 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3692); 3693int sqlite3_prepare16_v3( 3694 sqlite3 *db, /* Database handle */ 3695 const void *zSql, /* SQL statement, UTF-16 encoded */ 3696 int nByte, /* Maximum length of zSql in bytes. */ 3697 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3698 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3699 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3700); 3701 3702/* 3703** CAPI3REF: Retrieving Statement SQL 3704** METHOD: sqlite3_stmt 3705** 3706** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3707** SQL text used to create [prepared statement] P if P was 3708** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3709** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3710** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3711** string containing the SQL text of prepared statement P with 3712** [bound parameters] expanded. 3713** 3714** ^(For example, if a prepared statement is created using the SQL 3715** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3716** and parameter :xyz is unbound, then sqlite3_sql() will return 3717** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3718** will return "SELECT 2345,NULL".)^ 3719** 3720** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3721** is available to hold the result, or if the result would exceed the 3722** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3723** 3724** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3725** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3726** option causes sqlite3_expanded_sql() to always return NULL. 3727** 3728** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3729** automatically freed when the prepared statement is finalized. 3730** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3731** is obtained from [sqlite3_malloc()] and must be free by the application 3732** by passing it to [sqlite3_free()]. 3733*/ 3734const char *sqlite3_sql(sqlite3_stmt *pStmt); 3735char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3736 3737/* 3738** CAPI3REF: Determine If An SQL Statement Writes The Database 3739** METHOD: sqlite3_stmt 3740** 3741** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3742** and only if the [prepared statement] X makes no direct changes to 3743** the content of the database file. 3744** 3745** Note that [application-defined SQL functions] or 3746** [virtual tables] might change the database indirectly as a side effect. 3747** ^(For example, if an application defines a function "eval()" that 3748** calls [sqlite3_exec()], then the following SQL statement would 3749** change the database file through side-effects: 3750** 3751** <blockquote><pre> 3752** SELECT eval('DELETE FROM t1') FROM t2; 3753** </pre></blockquote> 3754** 3755** But because the [SELECT] statement does not change the database file 3756** directly, sqlite3_stmt_readonly() would still return true.)^ 3757** 3758** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3759** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3760** since the statements themselves do not actually modify the database but 3761** rather they control the timing of when other statements modify the 3762** database. ^The [ATTACH] and [DETACH] statements also cause 3763** sqlite3_stmt_readonly() to return true since, while those statements 3764** change the configuration of a database connection, they do not make 3765** changes to the content of the database files on disk. 3766** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3767** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3768** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3769** sqlite3_stmt_readonly() returns false for those commands. 3770*/ 3771int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3772 3773/* 3774** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3775** METHOD: sqlite3_stmt 3776** 3777** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3778** [prepared statement] S has been stepped at least once using 3779** [sqlite3_step(S)] but has neither run to completion (returned 3780** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3781** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3782** interface returns false if S is a NULL pointer. If S is not a 3783** NULL pointer and is not a pointer to a valid [prepared statement] 3784** object, then the behavior is undefined and probably undesirable. 3785** 3786** This interface can be used in combination [sqlite3_next_stmt()] 3787** to locate all prepared statements associated with a database 3788** connection that are in need of being reset. This can be used, 3789** for example, in diagnostic routines to search for prepared 3790** statements that are holding a transaction open. 3791*/ 3792int sqlite3_stmt_busy(sqlite3_stmt*); 3793 3794/* 3795** CAPI3REF: Dynamically Typed Value Object 3796** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3797** 3798** SQLite uses the sqlite3_value object to represent all values 3799** that can be stored in a database table. SQLite uses dynamic typing 3800** for the values it stores. ^Values stored in sqlite3_value objects 3801** can be integers, floating point values, strings, BLOBs, or NULL. 3802** 3803** An sqlite3_value object may be either "protected" or "unprotected". 3804** Some interfaces require a protected sqlite3_value. Other interfaces 3805** will accept either a protected or an unprotected sqlite3_value. 3806** Every interface that accepts sqlite3_value arguments specifies 3807** whether or not it requires a protected sqlite3_value. The 3808** [sqlite3_value_dup()] interface can be used to construct a new 3809** protected sqlite3_value from an unprotected sqlite3_value. 3810** 3811** The terms "protected" and "unprotected" refer to whether or not 3812** a mutex is held. An internal mutex is held for a protected 3813** sqlite3_value object but no mutex is held for an unprotected 3814** sqlite3_value object. If SQLite is compiled to be single-threaded 3815** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3816** or if SQLite is run in one of reduced mutex modes 3817** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3818** then there is no distinction between protected and unprotected 3819** sqlite3_value objects and they can be used interchangeably. However, 3820** for maximum code portability it is recommended that applications 3821** still make the distinction between protected and unprotected 3822** sqlite3_value objects even when not strictly required. 3823** 3824** ^The sqlite3_value objects that are passed as parameters into the 3825** implementation of [application-defined SQL functions] are protected. 3826** ^The sqlite3_value object returned by 3827** [sqlite3_column_value()] is unprotected. 3828** Unprotected sqlite3_value objects may only be used as arguments 3829** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3830** [sqlite3_value_dup()]. 3831** The [sqlite3_value_blob | sqlite3_value_type()] family of 3832** interfaces require protected sqlite3_value objects. 3833*/ 3834typedef struct sqlite3_value sqlite3_value; 3835 3836/* 3837** CAPI3REF: SQL Function Context Object 3838** 3839** The context in which an SQL function executes is stored in an 3840** sqlite3_context object. ^A pointer to an sqlite3_context object 3841** is always first parameter to [application-defined SQL functions]. 3842** The application-defined SQL function implementation will pass this 3843** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3844** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3845** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3846** and/or [sqlite3_set_auxdata()]. 3847*/ 3848typedef struct sqlite3_context sqlite3_context; 3849 3850/* 3851** CAPI3REF: Binding Values To Prepared Statements 3852** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3853** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3854** METHOD: sqlite3_stmt 3855** 3856** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3857** literals may be replaced by a [parameter] that matches one of following 3858** templates: 3859** 3860** <ul> 3861** <li> ? 3862** <li> ?NNN 3863** <li> :VVV 3864** <li> @VVV 3865** <li> $VVV 3866** </ul> 3867** 3868** In the templates above, NNN represents an integer literal, 3869** and VVV represents an alphanumeric identifier.)^ ^The values of these 3870** parameters (also called "host parameter names" or "SQL parameters") 3871** can be set using the sqlite3_bind_*() routines defined here. 3872** 3873** ^The first argument to the sqlite3_bind_*() routines is always 3874** a pointer to the [sqlite3_stmt] object returned from 3875** [sqlite3_prepare_v2()] or its variants. 3876** 3877** ^The second argument is the index of the SQL parameter to be set. 3878** ^The leftmost SQL parameter has an index of 1. ^When the same named 3879** SQL parameter is used more than once, second and subsequent 3880** occurrences have the same index as the first occurrence. 3881** ^The index for named parameters can be looked up using the 3882** [sqlite3_bind_parameter_index()] API if desired. ^The index 3883** for "?NNN" parameters is the value of NNN. 3884** ^The NNN value must be between 1 and the [sqlite3_limit()] 3885** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3886** 3887** ^The third argument is the value to bind to the parameter. 3888** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3889** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3890** is ignored and the end result is the same as sqlite3_bind_null(). 3891** 3892** ^(In those routines that have a fourth argument, its value is the 3893** number of bytes in the parameter. To be clear: the value is the 3894** number of <u>bytes</u> in the value, not the number of characters.)^ 3895** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3896** is negative, then the length of the string is 3897** the number of bytes up to the first zero terminator. 3898** If the fourth parameter to sqlite3_bind_blob() is negative, then 3899** the behavior is undefined. 3900** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3901** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3902** that parameter must be the byte offset 3903** where the NUL terminator would occur assuming the string were NUL 3904** terminated. If any NUL characters occur at byte offsets less than 3905** the value of the fourth parameter then the resulting string value will 3906** contain embedded NULs. The result of expressions involving strings 3907** with embedded NULs is undefined. 3908** 3909** ^The fifth argument to the BLOB and string binding interfaces 3910** is a destructor used to dispose of the BLOB or 3911** string after SQLite has finished with it. ^The destructor is called 3912** to dispose of the BLOB or string even if the call to bind API fails. 3913** ^If the fifth argument is 3914** the special value [SQLITE_STATIC], then SQLite assumes that the 3915** information is in static, unmanaged space and does not need to be freed. 3916** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3917** SQLite makes its own private copy of the data immediately, before 3918** the sqlite3_bind_*() routine returns. 3919** 3920** ^The sixth argument to sqlite3_bind_text64() must be one of 3921** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3922** to specify the encoding of the text in the third parameter. If 3923** the sixth argument to sqlite3_bind_text64() is not one of the 3924** allowed values shown above, or if the text encoding is different 3925** from the encoding specified by the sixth parameter, then the behavior 3926** is undefined. 3927** 3928** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3929** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3930** (just an integer to hold its size) while it is being processed. 3931** Zeroblobs are intended to serve as placeholders for BLOBs whose 3932** content is later written using 3933** [sqlite3_blob_open | incremental BLOB I/O] routines. 3934** ^A negative value for the zeroblob results in a zero-length BLOB. 3935** 3936** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3937** [prepared statement] S to have an SQL value of NULL, but to also be 3938** associated with the pointer P of type T. ^D is either a NULL pointer or 3939** a pointer to a destructor function for P. ^SQLite will invoke the 3940** destructor D with a single argument of P when it is finished using 3941** P. The T parameter should be a static string, preferably a string 3942** literal. The sqlite3_bind_pointer() routine is part of the 3943** [pointer passing interface] added for SQLite 3.20.0. 3944** 3945** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3946** for the [prepared statement] or with a prepared statement for which 3947** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3948** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3949** routine is passed a [prepared statement] that has been finalized, the 3950** result is undefined and probably harmful. 3951** 3952** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3953** ^Unbound parameters are interpreted as NULL. 3954** 3955** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3956** [error code] if anything goes wrong. 3957** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3958** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3959** [SQLITE_MAX_LENGTH]. 3960** ^[SQLITE_RANGE] is returned if the parameter 3961** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3962** 3963** See also: [sqlite3_bind_parameter_count()], 3964** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3965*/ 3966int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3967int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3968 void(*)(void*)); 3969int sqlite3_bind_double(sqlite3_stmt*, int, double); 3970int sqlite3_bind_int(sqlite3_stmt*, int, int); 3971int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3972int sqlite3_bind_null(sqlite3_stmt*, int); 3973int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3974int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3975int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3976 void(*)(void*), unsigned char encoding); 3977int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3978int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3979int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3980int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3981 3982/* 3983** CAPI3REF: Number Of SQL Parameters 3984** METHOD: sqlite3_stmt 3985** 3986** ^This routine can be used to find the number of [SQL parameters] 3987** in a [prepared statement]. SQL parameters are tokens of the 3988** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3989** placeholders for values that are [sqlite3_bind_blob | bound] 3990** to the parameters at a later time. 3991** 3992** ^(This routine actually returns the index of the largest (rightmost) 3993** parameter. For all forms except ?NNN, this will correspond to the 3994** number of unique parameters. If parameters of the ?NNN form are used, 3995** there may be gaps in the list.)^ 3996** 3997** See also: [sqlite3_bind_blob|sqlite3_bind()], 3998** [sqlite3_bind_parameter_name()], and 3999** [sqlite3_bind_parameter_index()]. 4000*/ 4001int sqlite3_bind_parameter_count(sqlite3_stmt*); 4002 4003/* 4004** CAPI3REF: Name Of A Host Parameter 4005** METHOD: sqlite3_stmt 4006** 4007** ^The sqlite3_bind_parameter_name(P,N) interface returns 4008** the name of the N-th [SQL parameter] in the [prepared statement] P. 4009** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4010** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4011** respectively. 4012** In other words, the initial ":" or "$" or "@" or "?" 4013** is included as part of the name.)^ 4014** ^Parameters of the form "?" without a following integer have no name 4015** and are referred to as "nameless" or "anonymous parameters". 4016** 4017** ^The first host parameter has an index of 1, not 0. 4018** 4019** ^If the value N is out of range or if the N-th parameter is 4020** nameless, then NULL is returned. ^The returned string is 4021** always in UTF-8 encoding even if the named parameter was 4022** originally specified as UTF-16 in [sqlite3_prepare16()], 4023** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4024** 4025** See also: [sqlite3_bind_blob|sqlite3_bind()], 4026** [sqlite3_bind_parameter_count()], and 4027** [sqlite3_bind_parameter_index()]. 4028*/ 4029const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4030 4031/* 4032** CAPI3REF: Index Of A Parameter With A Given Name 4033** METHOD: sqlite3_stmt 4034** 4035** ^Return the index of an SQL parameter given its name. ^The 4036** index value returned is suitable for use as the second 4037** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4038** is returned if no matching parameter is found. ^The parameter 4039** name must be given in UTF-8 even if the original statement 4040** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4041** [sqlite3_prepare16_v3()]. 4042** 4043** See also: [sqlite3_bind_blob|sqlite3_bind()], 4044** [sqlite3_bind_parameter_count()], and 4045** [sqlite3_bind_parameter_name()]. 4046*/ 4047int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4048 4049/* 4050** CAPI3REF: Reset All Bindings On A Prepared Statement 4051** METHOD: sqlite3_stmt 4052** 4053** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4054** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4055** ^Use this routine to reset all host parameters to NULL. 4056*/ 4057int sqlite3_clear_bindings(sqlite3_stmt*); 4058 4059/* 4060** CAPI3REF: Number Of Columns In A Result Set 4061** METHOD: sqlite3_stmt 4062** 4063** ^Return the number of columns in the result set returned by the 4064** [prepared statement]. ^If this routine returns 0, that means the 4065** [prepared statement] returns no data (for example an [UPDATE]). 4066** ^However, just because this routine returns a positive number does not 4067** mean that one or more rows of data will be returned. ^A SELECT statement 4068** will always have a positive sqlite3_column_count() but depending on the 4069** WHERE clause constraints and the table content, it might return no rows. 4070** 4071** See also: [sqlite3_data_count()] 4072*/ 4073int sqlite3_column_count(sqlite3_stmt *pStmt); 4074 4075/* 4076** CAPI3REF: Column Names In A Result Set 4077** METHOD: sqlite3_stmt 4078** 4079** ^These routines return the name assigned to a particular column 4080** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4081** interface returns a pointer to a zero-terminated UTF-8 string 4082** and sqlite3_column_name16() returns a pointer to a zero-terminated 4083** UTF-16 string. ^The first parameter is the [prepared statement] 4084** that implements the [SELECT] statement. ^The second parameter is the 4085** column number. ^The leftmost column is number 0. 4086** 4087** ^The returned string pointer is valid until either the [prepared statement] 4088** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4089** reprepared by the first call to [sqlite3_step()] for a particular run 4090** or until the next call to 4091** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4092** 4093** ^If sqlite3_malloc() fails during the processing of either routine 4094** (for example during a conversion from UTF-8 to UTF-16) then a 4095** NULL pointer is returned. 4096** 4097** ^The name of a result column is the value of the "AS" clause for 4098** that column, if there is an AS clause. If there is no AS clause 4099** then the name of the column is unspecified and may change from 4100** one release of SQLite to the next. 4101*/ 4102const char *sqlite3_column_name(sqlite3_stmt*, int N); 4103const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4104 4105/* 4106** CAPI3REF: Source Of Data In A Query Result 4107** METHOD: sqlite3_stmt 4108** 4109** ^These routines provide a means to determine the database, table, and 4110** table column that is the origin of a particular result column in 4111** [SELECT] statement. 4112** ^The name of the database or table or column can be returned as 4113** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4114** the database name, the _table_ routines return the table name, and 4115** the origin_ routines return the column name. 4116** ^The returned string is valid until the [prepared statement] is destroyed 4117** using [sqlite3_finalize()] or until the statement is automatically 4118** reprepared by the first call to [sqlite3_step()] for a particular run 4119** or until the same information is requested 4120** again in a different encoding. 4121** 4122** ^The names returned are the original un-aliased names of the 4123** database, table, and column. 4124** 4125** ^The first argument to these interfaces is a [prepared statement]. 4126** ^These functions return information about the Nth result column returned by 4127** the statement, where N is the second function argument. 4128** ^The left-most column is column 0 for these routines. 4129** 4130** ^If the Nth column returned by the statement is an expression or 4131** subquery and is not a column value, then all of these functions return 4132** NULL. ^These routine might also return NULL if a memory allocation error 4133** occurs. ^Otherwise, they return the name of the attached database, table, 4134** or column that query result column was extracted from. 4135** 4136** ^As with all other SQLite APIs, those whose names end with "16" return 4137** UTF-16 encoded strings and the other functions return UTF-8. 4138** 4139** ^These APIs are only available if the library was compiled with the 4140** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4141** 4142** If two or more threads call one or more of these routines against the same 4143** prepared statement and column at the same time then the results are 4144** undefined. 4145** 4146** If two or more threads call one or more 4147** [sqlite3_column_database_name | column metadata interfaces] 4148** for the same [prepared statement] and result column 4149** at the same time then the results are undefined. 4150*/ 4151const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4152const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4153const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4154const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4155const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4156const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4157 4158/* 4159** CAPI3REF: Declared Datatype Of A Query Result 4160** METHOD: sqlite3_stmt 4161** 4162** ^(The first parameter is a [prepared statement]. 4163** If this statement is a [SELECT] statement and the Nth column of the 4164** returned result set of that [SELECT] is a table column (not an 4165** expression or subquery) then the declared type of the table 4166** column is returned.)^ ^If the Nth column of the result set is an 4167** expression or subquery, then a NULL pointer is returned. 4168** ^The returned string is always UTF-8 encoded. 4169** 4170** ^(For example, given the database schema: 4171** 4172** CREATE TABLE t1(c1 VARIANT); 4173** 4174** and the following statement to be compiled: 4175** 4176** SELECT c1 + 1, c1 FROM t1; 4177** 4178** this routine would return the string "VARIANT" for the second result 4179** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4180** 4181** ^SQLite uses dynamic run-time typing. ^So just because a column 4182** is declared to contain a particular type does not mean that the 4183** data stored in that column is of the declared type. SQLite is 4184** strongly typed, but the typing is dynamic not static. ^Type 4185** is associated with individual values, not with the containers 4186** used to hold those values. 4187*/ 4188const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4189const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4190 4191/* 4192** CAPI3REF: Evaluate An SQL Statement 4193** METHOD: sqlite3_stmt 4194** 4195** After a [prepared statement] has been prepared using any of 4196** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4197** or [sqlite3_prepare16_v3()] or one of the legacy 4198** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4199** must be called one or more times to evaluate the statement. 4200** 4201** The details of the behavior of the sqlite3_step() interface depend 4202** on whether the statement was prepared using the newer "vX" interfaces 4203** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4204** [sqlite3_prepare16_v2()] or the older legacy 4205** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4206** new "vX" interface is recommended for new applications but the legacy 4207** interface will continue to be supported. 4208** 4209** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4210** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4211** ^With the "v2" interface, any of the other [result codes] or 4212** [extended result codes] might be returned as well. 4213** 4214** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4215** database locks it needs to do its job. ^If the statement is a [COMMIT] 4216** or occurs outside of an explicit transaction, then you can retry the 4217** statement. If the statement is not a [COMMIT] and occurs within an 4218** explicit transaction then you should rollback the transaction before 4219** continuing. 4220** 4221** ^[SQLITE_DONE] means that the statement has finished executing 4222** successfully. sqlite3_step() should not be called again on this virtual 4223** machine without first calling [sqlite3_reset()] to reset the virtual 4224** machine back to its initial state. 4225** 4226** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4227** is returned each time a new row of data is ready for processing by the 4228** caller. The values may be accessed using the [column access functions]. 4229** sqlite3_step() is called again to retrieve the next row of data. 4230** 4231** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4232** violation) has occurred. sqlite3_step() should not be called again on 4233** the VM. More information may be found by calling [sqlite3_errmsg()]. 4234** ^With the legacy interface, a more specific error code (for example, 4235** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4236** can be obtained by calling [sqlite3_reset()] on the 4237** [prepared statement]. ^In the "v2" interface, 4238** the more specific error code is returned directly by sqlite3_step(). 4239** 4240** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4241** Perhaps it was called on a [prepared statement] that has 4242** already been [sqlite3_finalize | finalized] or on one that had 4243** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4244** be the case that the same database connection is being used by two or 4245** more threads at the same moment in time. 4246** 4247** For all versions of SQLite up to and including 3.6.23.1, a call to 4248** [sqlite3_reset()] was required after sqlite3_step() returned anything 4249** other than [SQLITE_ROW] before any subsequent invocation of 4250** sqlite3_step(). Failure to reset the prepared statement using 4251** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4252** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4253** sqlite3_step() began 4254** calling [sqlite3_reset()] automatically in this circumstance rather 4255** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4256** break because any application that ever receives an SQLITE_MISUSE error 4257** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4258** can be used to restore the legacy behavior. 4259** 4260** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4261** API always returns a generic error code, [SQLITE_ERROR], following any 4262** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4263** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4264** specific [error codes] that better describes the error. 4265** We admit that this is a goofy design. The problem has been fixed 4266** with the "v2" interface. If you prepare all of your SQL statements 4267** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4268** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4269** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4270** then the more specific [error codes] are returned directly 4271** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4272*/ 4273int sqlite3_step(sqlite3_stmt*); 4274 4275/* 4276** CAPI3REF: Number of columns in a result set 4277** METHOD: sqlite3_stmt 4278** 4279** ^The sqlite3_data_count(P) interface returns the number of columns in the 4280** current row of the result set of [prepared statement] P. 4281** ^If prepared statement P does not have results ready to return 4282** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4283** interfaces) then sqlite3_data_count(P) returns 0. 4284** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4285** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4286** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4287** will return non-zero if previous call to [sqlite3_step](P) returned 4288** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4289** where it always returns zero since each step of that multi-step 4290** pragma returns 0 columns of data. 4291** 4292** See also: [sqlite3_column_count()] 4293*/ 4294int sqlite3_data_count(sqlite3_stmt *pStmt); 4295 4296/* 4297** CAPI3REF: Fundamental Datatypes 4298** KEYWORDS: SQLITE_TEXT 4299** 4300** ^(Every value in SQLite has one of five fundamental datatypes: 4301** 4302** <ul> 4303** <li> 64-bit signed integer 4304** <li> 64-bit IEEE floating point number 4305** <li> string 4306** <li> BLOB 4307** <li> NULL 4308** </ul>)^ 4309** 4310** These constants are codes for each of those types. 4311** 4312** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4313** for a completely different meaning. Software that links against both 4314** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4315** SQLITE_TEXT. 4316*/ 4317#define SQLITE_INTEGER 1 4318#define SQLITE_FLOAT 2 4319#define SQLITE_BLOB 4 4320#define SQLITE_NULL 5 4321#ifdef SQLITE_TEXT 4322# undef SQLITE_TEXT 4323#else 4324# define SQLITE_TEXT 3 4325#endif 4326#define SQLITE3_TEXT 3 4327 4328/* 4329** CAPI3REF: Result Values From A Query 4330** KEYWORDS: {column access functions} 4331** METHOD: sqlite3_stmt 4332** 4333** <b>Summary:</b> 4334** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4335** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4336** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4337** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4338** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4339** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4340** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4341** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4342** [sqlite3_value|unprotected sqlite3_value] object. 4343** <tr><td> <td> <td> 4344** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4345** or a UTF-8 TEXT result in bytes 4346** <tr><td><b>sqlite3_column_bytes16 </b> 4347** <td>→ <td>Size of UTF-16 4348** TEXT in bytes 4349** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4350** datatype of the result 4351** </table></blockquote> 4352** 4353** <b>Details:</b> 4354** 4355** ^These routines return information about a single column of the current 4356** result row of a query. ^In every case the first argument is a pointer 4357** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4358** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4359** and the second argument is the index of the column for which information 4360** should be returned. ^The leftmost column of the result set has the index 0. 4361** ^The number of columns in the result can be determined using 4362** [sqlite3_column_count()]. 4363** 4364** If the SQL statement does not currently point to a valid row, or if the 4365** column index is out of range, the result is undefined. 4366** These routines may only be called when the most recent call to 4367** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4368** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4369** If any of these routines are called after [sqlite3_reset()] or 4370** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4371** something other than [SQLITE_ROW], the results are undefined. 4372** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4373** are called from a different thread while any of these routines 4374** are pending, then the results are undefined. 4375** 4376** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4377** each return the value of a result column in a specific data format. If 4378** the result column is not initially in the requested format (for example, 4379** if the query returns an integer but the sqlite3_column_text() interface 4380** is used to extract the value) then an automatic type conversion is performed. 4381** 4382** ^The sqlite3_column_type() routine returns the 4383** [SQLITE_INTEGER | datatype code] for the initial data type 4384** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4385** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4386** The return value of sqlite3_column_type() can be used to decide which 4387** of the first six interface should be used to extract the column value. 4388** The value returned by sqlite3_column_type() is only meaningful if no 4389** automatic type conversions have occurred for the value in question. 4390** After a type conversion, the result of calling sqlite3_column_type() 4391** is undefined, though harmless. Future 4392** versions of SQLite may change the behavior of sqlite3_column_type() 4393** following a type conversion. 4394** 4395** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4396** or sqlite3_column_bytes16() interfaces can be used to determine the size 4397** of that BLOB or string. 4398** 4399** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4400** routine returns the number of bytes in that BLOB or string. 4401** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4402** the string to UTF-8 and then returns the number of bytes. 4403** ^If the result is a numeric value then sqlite3_column_bytes() uses 4404** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4405** the number of bytes in that string. 4406** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4407** 4408** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4409** routine returns the number of bytes in that BLOB or string. 4410** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4411** the string to UTF-16 and then returns the number of bytes. 4412** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4413** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4414** the number of bytes in that string. 4415** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4416** 4417** ^The values returned by [sqlite3_column_bytes()] and 4418** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4419** of the string. ^For clarity: the values returned by 4420** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4421** bytes in the string, not the number of characters. 4422** 4423** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4424** even empty strings, are always zero-terminated. ^The return 4425** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4426** 4427** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4428** [unprotected sqlite3_value] object. In a multithreaded environment, 4429** an unprotected sqlite3_value object may only be used safely with 4430** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4431** If the [unprotected sqlite3_value] object returned by 4432** [sqlite3_column_value()] is used in any other way, including calls 4433** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4434** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4435** Hence, the sqlite3_column_value() interface 4436** is normally only useful within the implementation of 4437** [application-defined SQL functions] or [virtual tables], not within 4438** top-level application code. 4439** 4440** The these routines may attempt to convert the datatype of the result. 4441** ^For example, if the internal representation is FLOAT and a text result 4442** is requested, [sqlite3_snprintf()] is used internally to perform the 4443** conversion automatically. ^(The following table details the conversions 4444** that are applied: 4445** 4446** <blockquote> 4447** <table border="1"> 4448** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4449** 4450** <tr><td> NULL <td> INTEGER <td> Result is 0 4451** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4452** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4453** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4454** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4455** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4456** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4457** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4458** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4459** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4460** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4461** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4462** <tr><td> TEXT <td> BLOB <td> No change 4463** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4464** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4465** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4466** </table> 4467** </blockquote>)^ 4468** 4469** Note that when type conversions occur, pointers returned by prior 4470** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4471** sqlite3_column_text16() may be invalidated. 4472** Type conversions and pointer invalidations might occur 4473** in the following cases: 4474** 4475** <ul> 4476** <li> The initial content is a BLOB and sqlite3_column_text() or 4477** sqlite3_column_text16() is called. A zero-terminator might 4478** need to be added to the string.</li> 4479** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4480** sqlite3_column_text16() is called. The content must be converted 4481** to UTF-16.</li> 4482** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4483** sqlite3_column_text() is called. The content must be converted 4484** to UTF-8.</li> 4485** </ul> 4486** 4487** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4488** not invalidate a prior pointer, though of course the content of the buffer 4489** that the prior pointer references will have been modified. Other kinds 4490** of conversion are done in place when it is possible, but sometimes they 4491** are not possible and in those cases prior pointers are invalidated. 4492** 4493** The safest policy is to invoke these routines 4494** in one of the following ways: 4495** 4496** <ul> 4497** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4498** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4499** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4500** </ul> 4501** 4502** In other words, you should call sqlite3_column_text(), 4503** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4504** into the desired format, then invoke sqlite3_column_bytes() or 4505** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4506** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4507** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4508** with calls to sqlite3_column_bytes(). 4509** 4510** ^The pointers returned are valid until a type conversion occurs as 4511** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4512** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4513** and BLOBs is freed automatically. Do not pass the pointers returned 4514** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4515** [sqlite3_free()]. 4516** 4517** ^(If a memory allocation error occurs during the evaluation of any 4518** of these routines, a default value is returned. The default value 4519** is either the integer 0, the floating point number 0.0, or a NULL 4520** pointer. Subsequent calls to [sqlite3_errcode()] will return 4521** [SQLITE_NOMEM].)^ 4522*/ 4523const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4524double sqlite3_column_double(sqlite3_stmt*, int iCol); 4525int sqlite3_column_int(sqlite3_stmt*, int iCol); 4526sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4527const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4528const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4529sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4530int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4531int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4532int sqlite3_column_type(sqlite3_stmt*, int iCol); 4533 4534/* 4535** CAPI3REF: Destroy A Prepared Statement Object 4536** DESTRUCTOR: sqlite3_stmt 4537** 4538** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4539** ^If the most recent evaluation of the statement encountered no errors 4540** or if the statement is never been evaluated, then sqlite3_finalize() returns 4541** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4542** sqlite3_finalize(S) returns the appropriate [error code] or 4543** [extended error code]. 4544** 4545** ^The sqlite3_finalize(S) routine can be called at any point during 4546** the life cycle of [prepared statement] S: 4547** before statement S is ever evaluated, after 4548** one or more calls to [sqlite3_reset()], or after any call 4549** to [sqlite3_step()] regardless of whether or not the statement has 4550** completed execution. 4551** 4552** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4553** 4554** The application must finalize every [prepared statement] in order to avoid 4555** resource leaks. It is a grievous error for the application to try to use 4556** a prepared statement after it has been finalized. Any use of a prepared 4557** statement after it has been finalized can result in undefined and 4558** undesirable behavior such as segfaults and heap corruption. 4559*/ 4560int sqlite3_finalize(sqlite3_stmt *pStmt); 4561 4562/* 4563** CAPI3REF: Reset A Prepared Statement Object 4564** METHOD: sqlite3_stmt 4565** 4566** The sqlite3_reset() function is called to reset a [prepared statement] 4567** object back to its initial state, ready to be re-executed. 4568** ^Any SQL statement variables that had values bound to them using 4569** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4570** Use [sqlite3_clear_bindings()] to reset the bindings. 4571** 4572** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4573** back to the beginning of its program. 4574** 4575** ^If the most recent call to [sqlite3_step(S)] for the 4576** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4577** or if [sqlite3_step(S)] has never before been called on S, 4578** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4579** 4580** ^If the most recent call to [sqlite3_step(S)] for the 4581** [prepared statement] S indicated an error, then 4582** [sqlite3_reset(S)] returns an appropriate [error code]. 4583** 4584** ^The [sqlite3_reset(S)] interface does not change the values 4585** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4586*/ 4587int sqlite3_reset(sqlite3_stmt *pStmt); 4588 4589/* 4590** CAPI3REF: Create Or Redefine SQL Functions 4591** KEYWORDS: {function creation routines} 4592** KEYWORDS: {application-defined SQL function} 4593** KEYWORDS: {application-defined SQL functions} 4594** METHOD: sqlite3 4595** 4596** ^These functions (collectively known as "function creation routines") 4597** are used to add SQL functions or aggregates or to redefine the behavior 4598** of existing SQL functions or aggregates. The only differences between 4599** these routines are the text encoding expected for 4600** the second parameter (the name of the function being created) 4601** and the presence or absence of a destructor callback for 4602** the application data pointer. 4603** 4604** ^The first parameter is the [database connection] to which the SQL 4605** function is to be added. ^If an application uses more than one database 4606** connection then application-defined SQL functions must be added 4607** to each database connection separately. 4608** 4609** ^The second parameter is the name of the SQL function to be created or 4610** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4611** representation, exclusive of the zero-terminator. ^Note that the name 4612** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4613** ^Any attempt to create a function with a longer name 4614** will result in [SQLITE_MISUSE] being returned. 4615** 4616** ^The third parameter (nArg) 4617** is the number of arguments that the SQL function or 4618** aggregate takes. ^If this parameter is -1, then the SQL function or 4619** aggregate may take any number of arguments between 0 and the limit 4620** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4621** parameter is less than -1 or greater than 127 then the behavior is 4622** undefined. 4623** 4624** ^The fourth parameter, eTextRep, specifies what 4625** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4626** its parameters. The application should set this parameter to 4627** [SQLITE_UTF16LE] if the function implementation invokes 4628** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4629** implementation invokes [sqlite3_value_text16be()] on an input, or 4630** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4631** otherwise. ^The same SQL function may be registered multiple times using 4632** different preferred text encodings, with different implementations for 4633** each encoding. 4634** ^When multiple implementations of the same function are available, SQLite 4635** will pick the one that involves the least amount of data conversion. 4636** 4637** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4638** to signal that the function will always return the same result given 4639** the same inputs within a single SQL statement. Most SQL functions are 4640** deterministic. The built-in [random()] SQL function is an example of a 4641** function that is not deterministic. The SQLite query planner is able to 4642** perform additional optimizations on deterministic functions, so use 4643** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4644** 4645** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4646** function can gain access to this pointer using [sqlite3_user_data()].)^ 4647** 4648** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4649** pointers to C-language functions that implement the SQL function or 4650** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4651** callback only; NULL pointers must be passed as the xStep and xFinal 4652** parameters. ^An aggregate SQL function requires an implementation of xStep 4653** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4654** SQL function or aggregate, pass NULL pointers for all three function 4655** callbacks. 4656** 4657** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4658** then it is destructor for the application data pointer. 4659** The destructor is invoked when the function is deleted, either by being 4660** overloaded or when the database connection closes.)^ 4661** ^The destructor is also invoked if the call to 4662** sqlite3_create_function_v2() fails. 4663** ^When the destructor callback of the tenth parameter is invoked, it 4664** is passed a single argument which is a copy of the application data 4665** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4666** 4667** ^It is permitted to register multiple implementations of the same 4668** functions with the same name but with either differing numbers of 4669** arguments or differing preferred text encodings. ^SQLite will use 4670** the implementation that most closely matches the way in which the 4671** SQL function is used. ^A function implementation with a non-negative 4672** nArg parameter is a better match than a function implementation with 4673** a negative nArg. ^A function where the preferred text encoding 4674** matches the database encoding is a better 4675** match than a function where the encoding is different. 4676** ^A function where the encoding difference is between UTF16le and UTF16be 4677** is a closer match than a function where the encoding difference is 4678** between UTF8 and UTF16. 4679** 4680** ^Built-in functions may be overloaded by new application-defined functions. 4681** 4682** ^An application-defined function is permitted to call other 4683** SQLite interfaces. However, such calls must not 4684** close the database connection nor finalize or reset the prepared 4685** statement in which the function is running. 4686*/ 4687int sqlite3_create_function( 4688 sqlite3 *db, 4689 const char *zFunctionName, 4690 int nArg, 4691 int eTextRep, 4692 void *pApp, 4693 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4694 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4695 void (*xFinal)(sqlite3_context*) 4696); 4697int sqlite3_create_function16( 4698 sqlite3 *db, 4699 const void *zFunctionName, 4700 int nArg, 4701 int eTextRep, 4702 void *pApp, 4703 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4704 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4705 void (*xFinal)(sqlite3_context*) 4706); 4707int sqlite3_create_function_v2( 4708 sqlite3 *db, 4709 const char *zFunctionName, 4710 int nArg, 4711 int eTextRep, 4712 void *pApp, 4713 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4714 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4715 void (*xFinal)(sqlite3_context*), 4716 void(*xDestroy)(void*) 4717); 4718 4719/* 4720** CAPI3REF: Text Encodings 4721** 4722** These constant define integer codes that represent the various 4723** text encodings supported by SQLite. 4724*/ 4725#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4726#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4727#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4728#define SQLITE_UTF16 4 /* Use native byte order */ 4729#define SQLITE_ANY 5 /* Deprecated */ 4730#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4731 4732/* 4733** CAPI3REF: Function Flags 4734** 4735** These constants may be ORed together with the 4736** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4737** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4738** [sqlite3_create_function_v2()]. 4739*/ 4740#define SQLITE_DETERMINISTIC 0x800 4741 4742/* 4743** CAPI3REF: Deprecated Functions 4744** DEPRECATED 4745** 4746** These functions are [deprecated]. In order to maintain 4747** backwards compatibility with older code, these functions continue 4748** to be supported. However, new applications should avoid 4749** the use of these functions. To encourage programmers to avoid 4750** these functions, we will not explain what they do. 4751*/ 4752#ifndef SQLITE_OMIT_DEPRECATED 4753SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4754SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4755SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4756SQLITE_DEPRECATED int sqlite3_global_recover(void); 4757SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4758SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4759 void*,sqlite3_int64); 4760#endif 4761 4762/* 4763** CAPI3REF: Obtaining SQL Values 4764** METHOD: sqlite3_value 4765** 4766** <b>Summary:</b> 4767** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4768** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4769** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4770** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4771** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4772** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4773** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4774** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4775** the native byteorder 4776** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4777** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4778** <tr><td> <td> <td> 4779** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4780** or a UTF-8 TEXT in bytes 4781** <tr><td><b>sqlite3_value_bytes16 </b> 4782** <td>→ <td>Size of UTF-16 4783** TEXT in bytes 4784** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4785** datatype of the value 4786** <tr><td><b>sqlite3_value_numeric_type </b> 4787** <td>→ <td>Best numeric datatype of the value 4788** </table></blockquote> 4789** 4790** <b>Details:</b> 4791** 4792** These routines extract type, size, and content information from 4793** [protected sqlite3_value] objects. Protected sqlite3_value objects 4794** are used to pass parameter information into implementation of 4795** [application-defined SQL functions] and [virtual tables]. 4796** 4797** These routines work only with [protected sqlite3_value] objects. 4798** Any attempt to use these routines on an [unprotected sqlite3_value] 4799** is not threadsafe. 4800** 4801** ^These routines work just like the corresponding [column access functions] 4802** except that these routines take a single [protected sqlite3_value] object 4803** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4804** 4805** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4806** in the native byte-order of the host machine. ^The 4807** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4808** extract UTF-16 strings as big-endian and little-endian respectively. 4809** 4810** ^If [sqlite3_value] object V was initialized 4811** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4812** and if X and Y are strings that compare equal according to strcmp(X,Y), 4813** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4814** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4815** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4816** 4817** ^(The sqlite3_value_type(V) interface returns the 4818** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4819** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4820** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4821** Other interfaces might change the datatype for an sqlite3_value object. 4822** For example, if the datatype is initially SQLITE_INTEGER and 4823** sqlite3_value_text(V) is called to extract a text value for that 4824** integer, then subsequent calls to sqlite3_value_type(V) might return 4825** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4826** occurs is undefined and may change from one release of SQLite to the next. 4827** 4828** ^(The sqlite3_value_numeric_type() interface attempts to apply 4829** numeric affinity to the value. This means that an attempt is 4830** made to convert the value to an integer or floating point. If 4831** such a conversion is possible without loss of information (in other 4832** words, if the value is a string that looks like a number) 4833** then the conversion is performed. Otherwise no conversion occurs. 4834** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4835** 4836** Please pay particular attention to the fact that the pointer returned 4837** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4838** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4839** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4840** or [sqlite3_value_text16()]. 4841** 4842** These routines must be called from the same thread as 4843** the SQL function that supplied the [sqlite3_value*] parameters. 4844*/ 4845const void *sqlite3_value_blob(sqlite3_value*); 4846double sqlite3_value_double(sqlite3_value*); 4847int sqlite3_value_int(sqlite3_value*); 4848sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4849void *sqlite3_value_pointer(sqlite3_value*, const char*); 4850const unsigned char *sqlite3_value_text(sqlite3_value*); 4851const void *sqlite3_value_text16(sqlite3_value*); 4852const void *sqlite3_value_text16le(sqlite3_value*); 4853const void *sqlite3_value_text16be(sqlite3_value*); 4854int sqlite3_value_bytes(sqlite3_value*); 4855int sqlite3_value_bytes16(sqlite3_value*); 4856int sqlite3_value_type(sqlite3_value*); 4857int sqlite3_value_numeric_type(sqlite3_value*); 4858 4859/* 4860** CAPI3REF: Finding The Subtype Of SQL Values 4861** METHOD: sqlite3_value 4862** 4863** The sqlite3_value_subtype(V) function returns the subtype for 4864** an [application-defined SQL function] argument V. The subtype 4865** information can be used to pass a limited amount of context from 4866** one SQL function to another. Use the [sqlite3_result_subtype()] 4867** routine to set the subtype for the return value of an SQL function. 4868*/ 4869unsigned int sqlite3_value_subtype(sqlite3_value*); 4870 4871/* 4872** CAPI3REF: Copy And Free SQL Values 4873** METHOD: sqlite3_value 4874** 4875** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4876** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4877** is a [protected sqlite3_value] object even if the input is not. 4878** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4879** memory allocation fails. 4880** 4881** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4882** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4883** then sqlite3_value_free(V) is a harmless no-op. 4884*/ 4885sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4886void sqlite3_value_free(sqlite3_value*); 4887 4888/* 4889** CAPI3REF: Obtain Aggregate Function Context 4890** METHOD: sqlite3_context 4891** 4892** Implementations of aggregate SQL functions use this 4893** routine to allocate memory for storing their state. 4894** 4895** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4896** for a particular aggregate function, SQLite 4897** allocates N of memory, zeroes out that memory, and returns a pointer 4898** to the new memory. ^On second and subsequent calls to 4899** sqlite3_aggregate_context() for the same aggregate function instance, 4900** the same buffer is returned. Sqlite3_aggregate_context() is normally 4901** called once for each invocation of the xStep callback and then one 4902** last time when the xFinal callback is invoked. ^(When no rows match 4903** an aggregate query, the xStep() callback of the aggregate function 4904** implementation is never called and xFinal() is called exactly once. 4905** In those cases, sqlite3_aggregate_context() might be called for the 4906** first time from within xFinal().)^ 4907** 4908** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4909** when first called if N is less than or equal to zero or if a memory 4910** allocate error occurs. 4911** 4912** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4913** determined by the N parameter on first successful call. Changing the 4914** value of N in subsequent call to sqlite3_aggregate_context() within 4915** the same aggregate function instance will not resize the memory 4916** allocation.)^ Within the xFinal callback, it is customary to set 4917** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4918** pointless memory allocations occur. 4919** 4920** ^SQLite automatically frees the memory allocated by 4921** sqlite3_aggregate_context() when the aggregate query concludes. 4922** 4923** The first parameter must be a copy of the 4924** [sqlite3_context | SQL function context] that is the first parameter 4925** to the xStep or xFinal callback routine that implements the aggregate 4926** function. 4927** 4928** This routine must be called from the same thread in which 4929** the aggregate SQL function is running. 4930*/ 4931void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4932 4933/* 4934** CAPI3REF: User Data For Functions 4935** METHOD: sqlite3_context 4936** 4937** ^The sqlite3_user_data() interface returns a copy of 4938** the pointer that was the pUserData parameter (the 5th parameter) 4939** of the [sqlite3_create_function()] 4940** and [sqlite3_create_function16()] routines that originally 4941** registered the application defined function. 4942** 4943** This routine must be called from the same thread in which 4944** the application-defined function is running. 4945*/ 4946void *sqlite3_user_data(sqlite3_context*); 4947 4948/* 4949** CAPI3REF: Database Connection For Functions 4950** METHOD: sqlite3_context 4951** 4952** ^The sqlite3_context_db_handle() interface returns a copy of 4953** the pointer to the [database connection] (the 1st parameter) 4954** of the [sqlite3_create_function()] 4955** and [sqlite3_create_function16()] routines that originally 4956** registered the application defined function. 4957*/ 4958sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4959 4960/* 4961** CAPI3REF: Function Auxiliary Data 4962** METHOD: sqlite3_context 4963** 4964** These functions may be used by (non-aggregate) SQL functions to 4965** associate metadata with argument values. If the same value is passed to 4966** multiple invocations of the same SQL function during query execution, under 4967** some circumstances the associated metadata may be preserved. An example 4968** of where this might be useful is in a regular-expression matching 4969** function. The compiled version of the regular expression can be stored as 4970** metadata associated with the pattern string. 4971** Then as long as the pattern string remains the same, 4972** the compiled regular expression can be reused on multiple 4973** invocations of the same function. 4974** 4975** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4976** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4977** value to the application-defined function. ^N is zero for the left-most 4978** function argument. ^If there is no metadata 4979** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4980** returns a NULL pointer. 4981** 4982** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4983** argument of the application-defined function. ^Subsequent 4984** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4985** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4986** NULL if the metadata has been discarded. 4987** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4988** SQLite will invoke the destructor function X with parameter P exactly 4989** once, when the metadata is discarded. 4990** SQLite is free to discard the metadata at any time, including: <ul> 4991** <li> ^(when the corresponding function parameter changes)^, or 4992** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4993** SQL statement)^, or 4994** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4995** parameter)^, or 4996** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4997** allocation error occurs.)^ </ul> 4998** 4999** Note the last bullet in particular. The destructor X in 5000** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5001** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5002** should be called near the end of the function implementation and the 5003** function implementation should not make any use of P after 5004** sqlite3_set_auxdata() has been called. 5005** 5006** ^(In practice, metadata is preserved between function calls for 5007** function parameters that are compile-time constants, including literal 5008** values and [parameters] and expressions composed from the same.)^ 5009** 5010** The value of the N parameter to these interfaces should be non-negative. 5011** Future enhancements may make use of negative N values to define new 5012** kinds of function caching behavior. 5013** 5014** These routines must be called from the same thread in which 5015** the SQL function is running. 5016*/ 5017void *sqlite3_get_auxdata(sqlite3_context*, int N); 5018void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5019 5020 5021/* 5022** CAPI3REF: Constants Defining Special Destructor Behavior 5023** 5024** These are special values for the destructor that is passed in as the 5025** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5026** argument is SQLITE_STATIC, it means that the content pointer is constant 5027** and will never change. It does not need to be destroyed. ^The 5028** SQLITE_TRANSIENT value means that the content will likely change in 5029** the near future and that SQLite should make its own private copy of 5030** the content before returning. 5031** 5032** The typedef is necessary to work around problems in certain 5033** C++ compilers. 5034*/ 5035typedef void (*sqlite3_destructor_type)(void*); 5036#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5037#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5038 5039/* 5040** CAPI3REF: Setting The Result Of An SQL Function 5041** METHOD: sqlite3_context 5042** 5043** These routines are used by the xFunc or xFinal callbacks that 5044** implement SQL functions and aggregates. See 5045** [sqlite3_create_function()] and [sqlite3_create_function16()] 5046** for additional information. 5047** 5048** These functions work very much like the [parameter binding] family of 5049** functions used to bind values to host parameters in prepared statements. 5050** Refer to the [SQL parameter] documentation for additional information. 5051** 5052** ^The sqlite3_result_blob() interface sets the result from 5053** an application-defined function to be the BLOB whose content is pointed 5054** to by the second parameter and which is N bytes long where N is the 5055** third parameter. 5056** 5057** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5058** interfaces set the result of the application-defined function to be 5059** a BLOB containing all zero bytes and N bytes in size. 5060** 5061** ^The sqlite3_result_double() interface sets the result from 5062** an application-defined function to be a floating point value specified 5063** by its 2nd argument. 5064** 5065** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5066** cause the implemented SQL function to throw an exception. 5067** ^SQLite uses the string pointed to by the 5068** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5069** as the text of an error message. ^SQLite interprets the error 5070** message string from sqlite3_result_error() as UTF-8. ^SQLite 5071** interprets the string from sqlite3_result_error16() as UTF-16 in native 5072** byte order. ^If the third parameter to sqlite3_result_error() 5073** or sqlite3_result_error16() is negative then SQLite takes as the error 5074** message all text up through the first zero character. 5075** ^If the third parameter to sqlite3_result_error() or 5076** sqlite3_result_error16() is non-negative then SQLite takes that many 5077** bytes (not characters) from the 2nd parameter as the error message. 5078** ^The sqlite3_result_error() and sqlite3_result_error16() 5079** routines make a private copy of the error message text before 5080** they return. Hence, the calling function can deallocate or 5081** modify the text after they return without harm. 5082** ^The sqlite3_result_error_code() function changes the error code 5083** returned by SQLite as a result of an error in a function. ^By default, 5084** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5085** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5086** 5087** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5088** error indicating that a string or BLOB is too long to represent. 5089** 5090** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5091** error indicating that a memory allocation failed. 5092** 5093** ^The sqlite3_result_int() interface sets the return value 5094** of the application-defined function to be the 32-bit signed integer 5095** value given in the 2nd argument. 5096** ^The sqlite3_result_int64() interface sets the return value 5097** of the application-defined function to be the 64-bit signed integer 5098** value given in the 2nd argument. 5099** 5100** ^The sqlite3_result_null() interface sets the return value 5101** of the application-defined function to be NULL. 5102** 5103** ^The sqlite3_result_text(), sqlite3_result_text16(), 5104** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5105** set the return value of the application-defined function to be 5106** a text string which is represented as UTF-8, UTF-16 native byte order, 5107** UTF-16 little endian, or UTF-16 big endian, respectively. 5108** ^The sqlite3_result_text64() interface sets the return value of an 5109** application-defined function to be a text string in an encoding 5110** specified by the fifth (and last) parameter, which must be one 5111** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5112** ^SQLite takes the text result from the application from 5113** the 2nd parameter of the sqlite3_result_text* interfaces. 5114** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5115** is negative, then SQLite takes result text from the 2nd parameter 5116** through the first zero character. 5117** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5118** is non-negative, then as many bytes (not characters) of the text 5119** pointed to by the 2nd parameter are taken as the application-defined 5120** function result. If the 3rd parameter is non-negative, then it 5121** must be the byte offset into the string where the NUL terminator would 5122** appear if the string where NUL terminated. If any NUL characters occur 5123** in the string at a byte offset that is less than the value of the 3rd 5124** parameter, then the resulting string will contain embedded NULs and the 5125** result of expressions operating on strings with embedded NULs is undefined. 5126** ^If the 4th parameter to the sqlite3_result_text* interfaces 5127** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5128** function as the destructor on the text or BLOB result when it has 5129** finished using that result. 5130** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5131** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5132** assumes that the text or BLOB result is in constant space and does not 5133** copy the content of the parameter nor call a destructor on the content 5134** when it has finished using that result. 5135** ^If the 4th parameter to the sqlite3_result_text* interfaces 5136** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5137** then SQLite makes a copy of the result into space obtained 5138** from [sqlite3_malloc()] before it returns. 5139** 5140** ^The sqlite3_result_value() interface sets the result of 5141** the application-defined function to be a copy of the 5142** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5143** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5144** so that the [sqlite3_value] specified in the parameter may change or 5145** be deallocated after sqlite3_result_value() returns without harm. 5146** ^A [protected sqlite3_value] object may always be used where an 5147** [unprotected sqlite3_value] object is required, so either 5148** kind of [sqlite3_value] object can be used with this interface. 5149** 5150** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5151** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5152** also associates the host-language pointer P or type T with that 5153** NULL value such that the pointer can be retrieved within an 5154** [application-defined SQL function] using [sqlite3_value_pointer()]. 5155** ^If the D parameter is not NULL, then it is a pointer to a destructor 5156** for the P parameter. ^SQLite invokes D with P as its only argument 5157** when SQLite is finished with P. The T parameter should be a static 5158** string and preferably a string literal. The sqlite3_result_pointer() 5159** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5160** 5161** If these routines are called from within the different thread 5162** than the one containing the application-defined function that received 5163** the [sqlite3_context] pointer, the results are undefined. 5164*/ 5165void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5166void sqlite3_result_blob64(sqlite3_context*,const void*, 5167 sqlite3_uint64,void(*)(void*)); 5168void sqlite3_result_double(sqlite3_context*, double); 5169void sqlite3_result_error(sqlite3_context*, const char*, int); 5170void sqlite3_result_error16(sqlite3_context*, const void*, int); 5171void sqlite3_result_error_toobig(sqlite3_context*); 5172void sqlite3_result_error_nomem(sqlite3_context*); 5173void sqlite3_result_error_code(sqlite3_context*, int); 5174void sqlite3_result_int(sqlite3_context*, int); 5175void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5176void sqlite3_result_null(sqlite3_context*); 5177void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5178void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5179 void(*)(void*), unsigned char encoding); 5180void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5181void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5182void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5183void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5184void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5185void sqlite3_result_zeroblob(sqlite3_context*, int n); 5186int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5187 5188 5189/* 5190** CAPI3REF: Setting The Subtype Of An SQL Function 5191** METHOD: sqlite3_context 5192** 5193** The sqlite3_result_subtype(C,T) function causes the subtype of 5194** the result from the [application-defined SQL function] with 5195** [sqlite3_context] C to be the value T. Only the lower 8 bits 5196** of the subtype T are preserved in current versions of SQLite; 5197** higher order bits are discarded. 5198** The number of subtype bytes preserved by SQLite might increase 5199** in future releases of SQLite. 5200*/ 5201void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5202 5203/* 5204** CAPI3REF: Define New Collating Sequences 5205** METHOD: sqlite3 5206** 5207** ^These functions add, remove, or modify a [collation] associated 5208** with the [database connection] specified as the first argument. 5209** 5210** ^The name of the collation is a UTF-8 string 5211** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5212** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5213** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5214** considered to be the same name. 5215** 5216** ^(The third argument (eTextRep) must be one of the constants: 5217** <ul> 5218** <li> [SQLITE_UTF8], 5219** <li> [SQLITE_UTF16LE], 5220** <li> [SQLITE_UTF16BE], 5221** <li> [SQLITE_UTF16], or 5222** <li> [SQLITE_UTF16_ALIGNED]. 5223** </ul>)^ 5224** ^The eTextRep argument determines the encoding of strings passed 5225** to the collating function callback, xCallback. 5226** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5227** force strings to be UTF16 with native byte order. 5228** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5229** on an even byte address. 5230** 5231** ^The fourth argument, pArg, is an application data pointer that is passed 5232** through as the first argument to the collating function callback. 5233** 5234** ^The fifth argument, xCallback, is a pointer to the collating function. 5235** ^Multiple collating functions can be registered using the same name but 5236** with different eTextRep parameters and SQLite will use whichever 5237** function requires the least amount of data transformation. 5238** ^If the xCallback argument is NULL then the collating function is 5239** deleted. ^When all collating functions having the same name are deleted, 5240** that collation is no longer usable. 5241** 5242** ^The collating function callback is invoked with a copy of the pArg 5243** application data pointer and with two strings in the encoding specified 5244** by the eTextRep argument. The collating function must return an 5245** integer that is negative, zero, or positive 5246** if the first string is less than, equal to, or greater than the second, 5247** respectively. A collating function must always return the same answer 5248** given the same inputs. If two or more collating functions are registered 5249** to the same collation name (using different eTextRep values) then all 5250** must give an equivalent answer when invoked with equivalent strings. 5251** The collating function must obey the following properties for all 5252** strings A, B, and C: 5253** 5254** <ol> 5255** <li> If A==B then B==A. 5256** <li> If A==B and B==C then A==C. 5257** <li> If A<B THEN B>A. 5258** <li> If A<B and B<C then A<C. 5259** </ol> 5260** 5261** If a collating function fails any of the above constraints and that 5262** collating function is registered and used, then the behavior of SQLite 5263** is undefined. 5264** 5265** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5266** with the addition that the xDestroy callback is invoked on pArg when 5267** the collating function is deleted. 5268** ^Collating functions are deleted when they are overridden by later 5269** calls to the collation creation functions or when the 5270** [database connection] is closed using [sqlite3_close()]. 5271** 5272** ^The xDestroy callback is <u>not</u> called if the 5273** sqlite3_create_collation_v2() function fails. Applications that invoke 5274** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5275** check the return code and dispose of the application data pointer 5276** themselves rather than expecting SQLite to deal with it for them. 5277** This is different from every other SQLite interface. The inconsistency 5278** is unfortunate but cannot be changed without breaking backwards 5279** compatibility. 5280** 5281** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5282*/ 5283int sqlite3_create_collation( 5284 sqlite3*, 5285 const char *zName, 5286 int eTextRep, 5287 void *pArg, 5288 int(*xCompare)(void*,int,const void*,int,const void*) 5289); 5290int sqlite3_create_collation_v2( 5291 sqlite3*, 5292 const char *zName, 5293 int eTextRep, 5294 void *pArg, 5295 int(*xCompare)(void*,int,const void*,int,const void*), 5296 void(*xDestroy)(void*) 5297); 5298int sqlite3_create_collation16( 5299 sqlite3*, 5300 const void *zName, 5301 int eTextRep, 5302 void *pArg, 5303 int(*xCompare)(void*,int,const void*,int,const void*) 5304); 5305 5306/* 5307** CAPI3REF: Collation Needed Callbacks 5308** METHOD: sqlite3 5309** 5310** ^To avoid having to register all collation sequences before a database 5311** can be used, a single callback function may be registered with the 5312** [database connection] to be invoked whenever an undefined collation 5313** sequence is required. 5314** 5315** ^If the function is registered using the sqlite3_collation_needed() API, 5316** then it is passed the names of undefined collation sequences as strings 5317** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5318** the names are passed as UTF-16 in machine native byte order. 5319** ^A call to either function replaces the existing collation-needed callback. 5320** 5321** ^(When the callback is invoked, the first argument passed is a copy 5322** of the second argument to sqlite3_collation_needed() or 5323** sqlite3_collation_needed16(). The second argument is the database 5324** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5325** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5326** sequence function required. The fourth parameter is the name of the 5327** required collation sequence.)^ 5328** 5329** The callback function should register the desired collation using 5330** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5331** [sqlite3_create_collation_v2()]. 5332*/ 5333int sqlite3_collation_needed( 5334 sqlite3*, 5335 void*, 5336 void(*)(void*,sqlite3*,int eTextRep,const char*) 5337); 5338int sqlite3_collation_needed16( 5339 sqlite3*, 5340 void*, 5341 void(*)(void*,sqlite3*,int eTextRep,const void*) 5342); 5343 5344#ifdef SQLITE_HAS_CODEC 5345/* 5346** Specify the key for an encrypted database. This routine should be 5347** called right after sqlite3_open(). 5348** 5349** The code to implement this API is not available in the public release 5350** of SQLite. 5351*/ 5352int sqlite3_key( 5353 sqlite3 *db, /* Database to be rekeyed */ 5354 const void *pKey, int nKey /* The key */ 5355); 5356int sqlite3_key_v2( 5357 sqlite3 *db, /* Database to be rekeyed */ 5358 const char *zDbName, /* Name of the database */ 5359 const void *pKey, int nKey /* The key */ 5360); 5361 5362/* 5363** Change the key on an open database. If the current database is not 5364** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5365** database is decrypted. 5366** 5367** The code to implement this API is not available in the public release 5368** of SQLite. 5369*/ 5370int sqlite3_rekey( 5371 sqlite3 *db, /* Database to be rekeyed */ 5372 const void *pKey, int nKey /* The new key */ 5373); 5374int sqlite3_rekey_v2( 5375 sqlite3 *db, /* Database to be rekeyed */ 5376 const char *zDbName, /* Name of the database */ 5377 const void *pKey, int nKey /* The new key */ 5378); 5379 5380/* 5381** Specify the activation key for a SEE database. Unless 5382** activated, none of the SEE routines will work. 5383*/ 5384void sqlite3_activate_see( 5385 const char *zPassPhrase /* Activation phrase */ 5386); 5387#endif 5388 5389#ifdef SQLITE_ENABLE_CEROD 5390/* 5391** Specify the activation key for a CEROD database. Unless 5392** activated, none of the CEROD routines will work. 5393*/ 5394void sqlite3_activate_cerod( 5395 const char *zPassPhrase /* Activation phrase */ 5396); 5397#endif 5398 5399/* 5400** CAPI3REF: Suspend Execution For A Short Time 5401** 5402** The sqlite3_sleep() function causes the current thread to suspend execution 5403** for at least a number of milliseconds specified in its parameter. 5404** 5405** If the operating system does not support sleep requests with 5406** millisecond time resolution, then the time will be rounded up to 5407** the nearest second. The number of milliseconds of sleep actually 5408** requested from the operating system is returned. 5409** 5410** ^SQLite implements this interface by calling the xSleep() 5411** method of the default [sqlite3_vfs] object. If the xSleep() method 5412** of the default VFS is not implemented correctly, or not implemented at 5413** all, then the behavior of sqlite3_sleep() may deviate from the description 5414** in the previous paragraphs. 5415*/ 5416int sqlite3_sleep(int); 5417 5418/* 5419** CAPI3REF: Name Of The Folder Holding Temporary Files 5420** 5421** ^(If this global variable is made to point to a string which is 5422** the name of a folder (a.k.a. directory), then all temporary files 5423** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5424** will be placed in that directory.)^ ^If this variable 5425** is a NULL pointer, then SQLite performs a search for an appropriate 5426** temporary file directory. 5427** 5428** Applications are strongly discouraged from using this global variable. 5429** It is required to set a temporary folder on Windows Runtime (WinRT). 5430** But for all other platforms, it is highly recommended that applications 5431** neither read nor write this variable. This global variable is a relic 5432** that exists for backwards compatibility of legacy applications and should 5433** be avoided in new projects. 5434** 5435** It is not safe to read or modify this variable in more than one 5436** thread at a time. It is not safe to read or modify this variable 5437** if a [database connection] is being used at the same time in a separate 5438** thread. 5439** It is intended that this variable be set once 5440** as part of process initialization and before any SQLite interface 5441** routines have been called and that this variable remain unchanged 5442** thereafter. 5443** 5444** ^The [temp_store_directory pragma] may modify this variable and cause 5445** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5446** the [temp_store_directory pragma] always assumes that any string 5447** that this variable points to is held in memory obtained from 5448** [sqlite3_malloc] and the pragma may attempt to free that memory 5449** using [sqlite3_free]. 5450** Hence, if this variable is modified directly, either it should be 5451** made NULL or made to point to memory obtained from [sqlite3_malloc] 5452** or else the use of the [temp_store_directory pragma] should be avoided. 5453** Except when requested by the [temp_store_directory pragma], SQLite 5454** does not free the memory that sqlite3_temp_directory points to. If 5455** the application wants that memory to be freed, it must do 5456** so itself, taking care to only do so after all [database connection] 5457** objects have been destroyed. 5458** 5459** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5460** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5461** features that require the use of temporary files may fail. Here is an 5462** example of how to do this using C++ with the Windows Runtime: 5463** 5464** <blockquote><pre> 5465** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5466** TemporaryFolder->Path->Data(); 5467** char zPathBuf[MAX_PATH + 1]; 5468** memset(zPathBuf, 0, sizeof(zPathBuf)); 5469** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5470** NULL, NULL); 5471** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5472** </pre></blockquote> 5473*/ 5474SQLITE_EXTERN char *sqlite3_temp_directory; 5475 5476/* 5477** CAPI3REF: Name Of The Folder Holding Database Files 5478** 5479** ^(If this global variable is made to point to a string which is 5480** the name of a folder (a.k.a. directory), then all database files 5481** specified with a relative pathname and created or accessed by 5482** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5483** to be relative to that directory.)^ ^If this variable is a NULL 5484** pointer, then SQLite assumes that all database files specified 5485** with a relative pathname are relative to the current directory 5486** for the process. Only the windows VFS makes use of this global 5487** variable; it is ignored by the unix VFS. 5488** 5489** Changing the value of this variable while a database connection is 5490** open can result in a corrupt database. 5491** 5492** It is not safe to read or modify this variable in more than one 5493** thread at a time. It is not safe to read or modify this variable 5494** if a [database connection] is being used at the same time in a separate 5495** thread. 5496** It is intended that this variable be set once 5497** as part of process initialization and before any SQLite interface 5498** routines have been called and that this variable remain unchanged 5499** thereafter. 5500** 5501** ^The [data_store_directory pragma] may modify this variable and cause 5502** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5503** the [data_store_directory pragma] always assumes that any string 5504** that this variable points to is held in memory obtained from 5505** [sqlite3_malloc] and the pragma may attempt to free that memory 5506** using [sqlite3_free]. 5507** Hence, if this variable is modified directly, either it should be 5508** made NULL or made to point to memory obtained from [sqlite3_malloc] 5509** or else the use of the [data_store_directory pragma] should be avoided. 5510*/ 5511SQLITE_EXTERN char *sqlite3_data_directory; 5512 5513/* 5514** CAPI3REF: Test For Auto-Commit Mode 5515** KEYWORDS: {autocommit mode} 5516** METHOD: sqlite3 5517** 5518** ^The sqlite3_get_autocommit() interface returns non-zero or 5519** zero if the given database connection is or is not in autocommit mode, 5520** respectively. ^Autocommit mode is on by default. 5521** ^Autocommit mode is disabled by a [BEGIN] statement. 5522** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5523** 5524** If certain kinds of errors occur on a statement within a multi-statement 5525** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5526** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5527** transaction might be rolled back automatically. The only way to 5528** find out whether SQLite automatically rolled back the transaction after 5529** an error is to use this function. 5530** 5531** If another thread changes the autocommit status of the database 5532** connection while this routine is running, then the return value 5533** is undefined. 5534*/ 5535int sqlite3_get_autocommit(sqlite3*); 5536 5537/* 5538** CAPI3REF: Find The Database Handle Of A Prepared Statement 5539** METHOD: sqlite3_stmt 5540** 5541** ^The sqlite3_db_handle interface returns the [database connection] handle 5542** to which a [prepared statement] belongs. ^The [database connection] 5543** returned by sqlite3_db_handle is the same [database connection] 5544** that was the first argument 5545** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5546** create the statement in the first place. 5547*/ 5548sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5549 5550/* 5551** CAPI3REF: Return The Filename For A Database Connection 5552** METHOD: sqlite3 5553** 5554** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5555** associated with database N of connection D. ^The main database file 5556** has the name "main". If there is no attached database N on the database 5557** connection D, or if database N is a temporary or in-memory database, then 5558** a NULL pointer is returned. 5559** 5560** ^The filename returned by this function is the output of the 5561** xFullPathname method of the [VFS]. ^In other words, the filename 5562** will be an absolute pathname, even if the filename used 5563** to open the database originally was a URI or relative pathname. 5564*/ 5565const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5566 5567/* 5568** CAPI3REF: Determine if a database is read-only 5569** METHOD: sqlite3 5570** 5571** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5572** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5573** the name of a database on connection D. 5574*/ 5575int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5576 5577/* 5578** CAPI3REF: Find the next prepared statement 5579** METHOD: sqlite3 5580** 5581** ^This interface returns a pointer to the next [prepared statement] after 5582** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5583** then this interface returns a pointer to the first prepared statement 5584** associated with the database connection pDb. ^If no prepared statement 5585** satisfies the conditions of this routine, it returns NULL. 5586** 5587** The [database connection] pointer D in a call to 5588** [sqlite3_next_stmt(D,S)] must refer to an open database 5589** connection and in particular must not be a NULL pointer. 5590*/ 5591sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5592 5593/* 5594** CAPI3REF: Commit And Rollback Notification Callbacks 5595** METHOD: sqlite3 5596** 5597** ^The sqlite3_commit_hook() interface registers a callback 5598** function to be invoked whenever a transaction is [COMMIT | committed]. 5599** ^Any callback set by a previous call to sqlite3_commit_hook() 5600** for the same database connection is overridden. 5601** ^The sqlite3_rollback_hook() interface registers a callback 5602** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5603** ^Any callback set by a previous call to sqlite3_rollback_hook() 5604** for the same database connection is overridden. 5605** ^The pArg argument is passed through to the callback. 5606** ^If the callback on a commit hook function returns non-zero, 5607** then the commit is converted into a rollback. 5608** 5609** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5610** return the P argument from the previous call of the same function 5611** on the same [database connection] D, or NULL for 5612** the first call for each function on D. 5613** 5614** The commit and rollback hook callbacks are not reentrant. 5615** The callback implementation must not do anything that will modify 5616** the database connection that invoked the callback. Any actions 5617** to modify the database connection must be deferred until after the 5618** completion of the [sqlite3_step()] call that triggered the commit 5619** or rollback hook in the first place. 5620** Note that running any other SQL statements, including SELECT statements, 5621** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5622** the database connections for the meaning of "modify" in this paragraph. 5623** 5624** ^Registering a NULL function disables the callback. 5625** 5626** ^When the commit hook callback routine returns zero, the [COMMIT] 5627** operation is allowed to continue normally. ^If the commit hook 5628** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5629** ^The rollback hook is invoked on a rollback that results from a commit 5630** hook returning non-zero, just as it would be with any other rollback. 5631** 5632** ^For the purposes of this API, a transaction is said to have been 5633** rolled back if an explicit "ROLLBACK" statement is executed, or 5634** an error or constraint causes an implicit rollback to occur. 5635** ^The rollback callback is not invoked if a transaction is 5636** automatically rolled back because the database connection is closed. 5637** 5638** See also the [sqlite3_update_hook()] interface. 5639*/ 5640void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5641void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5642 5643/* 5644** CAPI3REF: Data Change Notification Callbacks 5645** METHOD: sqlite3 5646** 5647** ^The sqlite3_update_hook() interface registers a callback function 5648** with the [database connection] identified by the first argument 5649** to be invoked whenever a row is updated, inserted or deleted in 5650** a [rowid table]. 5651** ^Any callback set by a previous call to this function 5652** for the same database connection is overridden. 5653** 5654** ^The second argument is a pointer to the function to invoke when a 5655** row is updated, inserted or deleted in a rowid table. 5656** ^The first argument to the callback is a copy of the third argument 5657** to sqlite3_update_hook(). 5658** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5659** or [SQLITE_UPDATE], depending on the operation that caused the callback 5660** to be invoked. 5661** ^The third and fourth arguments to the callback contain pointers to the 5662** database and table name containing the affected row. 5663** ^The final callback parameter is the [rowid] of the row. 5664** ^In the case of an update, this is the [rowid] after the update takes place. 5665** 5666** ^(The update hook is not invoked when internal system tables are 5667** modified (i.e. sqlite_master and sqlite_sequence).)^ 5668** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5669** 5670** ^In the current implementation, the update hook 5671** is not invoked when conflicting rows are deleted because of an 5672** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5673** invoked when rows are deleted using the [truncate optimization]. 5674** The exceptions defined in this paragraph might change in a future 5675** release of SQLite. 5676** 5677** The update hook implementation must not do anything that will modify 5678** the database connection that invoked the update hook. Any actions 5679** to modify the database connection must be deferred until after the 5680** completion of the [sqlite3_step()] call that triggered the update hook. 5681** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5682** database connections for the meaning of "modify" in this paragraph. 5683** 5684** ^The sqlite3_update_hook(D,C,P) function 5685** returns the P argument from the previous call 5686** on the same [database connection] D, or NULL for 5687** the first call on D. 5688** 5689** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5690** and [sqlite3_preupdate_hook()] interfaces. 5691*/ 5692void *sqlite3_update_hook( 5693 sqlite3*, 5694 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5695 void* 5696); 5697 5698/* 5699** CAPI3REF: Enable Or Disable Shared Pager Cache 5700** 5701** ^(This routine enables or disables the sharing of the database cache 5702** and schema data structures between [database connection | connections] 5703** to the same database. Sharing is enabled if the argument is true 5704** and disabled if the argument is false.)^ 5705** 5706** ^Cache sharing is enabled and disabled for an entire process. 5707** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5708** In prior versions of SQLite, 5709** sharing was enabled or disabled for each thread separately. 5710** 5711** ^(The cache sharing mode set by this interface effects all subsequent 5712** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5713** Existing database connections continue use the sharing mode 5714** that was in effect at the time they were opened.)^ 5715** 5716** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5717** successfully. An [error code] is returned otherwise.)^ 5718** 5719** ^Shared cache is disabled by default. But this might change in 5720** future releases of SQLite. Applications that care about shared 5721** cache setting should set it explicitly. 5722** 5723** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5724** and will always return SQLITE_MISUSE. On those systems, 5725** shared cache mode should be enabled per-database connection via 5726** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5727** 5728** This interface is threadsafe on processors where writing a 5729** 32-bit integer is atomic. 5730** 5731** See Also: [SQLite Shared-Cache Mode] 5732*/ 5733int sqlite3_enable_shared_cache(int); 5734 5735/* 5736** CAPI3REF: Attempt To Free Heap Memory 5737** 5738** ^The sqlite3_release_memory() interface attempts to free N bytes 5739** of heap memory by deallocating non-essential memory allocations 5740** held by the database library. Memory used to cache database 5741** pages to improve performance is an example of non-essential memory. 5742** ^sqlite3_release_memory() returns the number of bytes actually freed, 5743** which might be more or less than the amount requested. 5744** ^The sqlite3_release_memory() routine is a no-op returning zero 5745** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5746** 5747** See also: [sqlite3_db_release_memory()] 5748*/ 5749int sqlite3_release_memory(int); 5750 5751/* 5752** CAPI3REF: Free Memory Used By A Database Connection 5753** METHOD: sqlite3 5754** 5755** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5756** memory as possible from database connection D. Unlike the 5757** [sqlite3_release_memory()] interface, this interface is in effect even 5758** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5759** omitted. 5760** 5761** See also: [sqlite3_release_memory()] 5762*/ 5763int sqlite3_db_release_memory(sqlite3*); 5764 5765/* 5766** CAPI3REF: Impose A Limit On Heap Size 5767** 5768** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5769** soft limit on the amount of heap memory that may be allocated by SQLite. 5770** ^SQLite strives to keep heap memory utilization below the soft heap 5771** limit by reducing the number of pages held in the page cache 5772** as heap memory usages approaches the limit. 5773** ^The soft heap limit is "soft" because even though SQLite strives to stay 5774** below the limit, it will exceed the limit rather than generate 5775** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5776** is advisory only. 5777** 5778** ^The return value from sqlite3_soft_heap_limit64() is the size of 5779** the soft heap limit prior to the call, or negative in the case of an 5780** error. ^If the argument N is negative 5781** then no change is made to the soft heap limit. Hence, the current 5782** size of the soft heap limit can be determined by invoking 5783** sqlite3_soft_heap_limit64() with a negative argument. 5784** 5785** ^If the argument N is zero then the soft heap limit is disabled. 5786** 5787** ^(The soft heap limit is not enforced in the current implementation 5788** if one or more of following conditions are true: 5789** 5790** <ul> 5791** <li> The soft heap limit is set to zero. 5792** <li> Memory accounting is disabled using a combination of the 5793** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5794** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5795** <li> An alternative page cache implementation is specified using 5796** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5797** <li> The page cache allocates from its own memory pool supplied 5798** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5799** from the heap. 5800** </ul>)^ 5801** 5802** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5803** the soft heap limit is enforced 5804** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5805** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5806** the soft heap limit is enforced on every memory allocation. Without 5807** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5808** when memory is allocated by the page cache. Testing suggests that because 5809** the page cache is the predominate memory user in SQLite, most 5810** applications will achieve adequate soft heap limit enforcement without 5811** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5812** 5813** The circumstances under which SQLite will enforce the soft heap limit may 5814** changes in future releases of SQLite. 5815*/ 5816sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5817 5818/* 5819** CAPI3REF: Deprecated Soft Heap Limit Interface 5820** DEPRECATED 5821** 5822** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5823** interface. This routine is provided for historical compatibility 5824** only. All new applications should use the 5825** [sqlite3_soft_heap_limit64()] interface rather than this one. 5826*/ 5827SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5828 5829 5830/* 5831** CAPI3REF: Extract Metadata About A Column Of A Table 5832** METHOD: sqlite3 5833** 5834** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5835** information about column C of table T in database D 5836** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5837** interface returns SQLITE_OK and fills in the non-NULL pointers in 5838** the final five arguments with appropriate values if the specified 5839** column exists. ^The sqlite3_table_column_metadata() interface returns 5840** SQLITE_ERROR and if the specified column does not exist. 5841** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5842** NULL pointer, then this routine simply checks for the existence of the 5843** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5844** does not. If the table name parameter T in a call to 5845** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5846** undefined behavior. 5847** 5848** ^The column is identified by the second, third and fourth parameters to 5849** this function. ^(The second parameter is either the name of the database 5850** (i.e. "main", "temp", or an attached database) containing the specified 5851** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5852** for the table using the same algorithm used by the database engine to 5853** resolve unqualified table references. 5854** 5855** ^The third and fourth parameters to this function are the table and column 5856** name of the desired column, respectively. 5857** 5858** ^Metadata is returned by writing to the memory locations passed as the 5th 5859** and subsequent parameters to this function. ^Any of these arguments may be 5860** NULL, in which case the corresponding element of metadata is omitted. 5861** 5862** ^(<blockquote> 5863** <table border="1"> 5864** <tr><th> Parameter <th> Output<br>Type <th> Description 5865** 5866** <tr><td> 5th <td> const char* <td> Data type 5867** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5868** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5869** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5870** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5871** </table> 5872** </blockquote>)^ 5873** 5874** ^The memory pointed to by the character pointers returned for the 5875** declaration type and collation sequence is valid until the next 5876** call to any SQLite API function. 5877** 5878** ^If the specified table is actually a view, an [error code] is returned. 5879** 5880** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5881** is not a [WITHOUT ROWID] table and an 5882** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5883** parameters are set for the explicitly declared column. ^(If there is no 5884** [INTEGER PRIMARY KEY] column, then the outputs 5885** for the [rowid] are set as follows: 5886** 5887** <pre> 5888** data type: "INTEGER" 5889** collation sequence: "BINARY" 5890** not null: 0 5891** primary key: 1 5892** auto increment: 0 5893** </pre>)^ 5894** 5895** ^This function causes all database schemas to be read from disk and 5896** parsed, if that has not already been done, and returns an error if 5897** any errors are encountered while loading the schema. 5898*/ 5899int sqlite3_table_column_metadata( 5900 sqlite3 *db, /* Connection handle */ 5901 const char *zDbName, /* Database name or NULL */ 5902 const char *zTableName, /* Table name */ 5903 const char *zColumnName, /* Column name */ 5904 char const **pzDataType, /* OUTPUT: Declared data type */ 5905 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5906 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5907 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5908 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5909); 5910 5911/* 5912** CAPI3REF: Load An Extension 5913** METHOD: sqlite3 5914** 5915** ^This interface loads an SQLite extension library from the named file. 5916** 5917** ^The sqlite3_load_extension() interface attempts to load an 5918** [SQLite extension] library contained in the file zFile. If 5919** the file cannot be loaded directly, attempts are made to load 5920** with various operating-system specific extensions added. 5921** So for example, if "samplelib" cannot be loaded, then names like 5922** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5923** be tried also. 5924** 5925** ^The entry point is zProc. 5926** ^(zProc may be 0, in which case SQLite will try to come up with an 5927** entry point name on its own. It first tries "sqlite3_extension_init". 5928** If that does not work, it constructs a name "sqlite3_X_init" where the 5929** X is consists of the lower-case equivalent of all ASCII alphabetic 5930** characters in the filename from the last "/" to the first following 5931** "." and omitting any initial "lib".)^ 5932** ^The sqlite3_load_extension() interface returns 5933** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5934** ^If an error occurs and pzErrMsg is not 0, then the 5935** [sqlite3_load_extension()] interface shall attempt to 5936** fill *pzErrMsg with error message text stored in memory 5937** obtained from [sqlite3_malloc()]. The calling function 5938** should free this memory by calling [sqlite3_free()]. 5939** 5940** ^Extension loading must be enabled using 5941** [sqlite3_enable_load_extension()] or 5942** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5943** prior to calling this API, 5944** otherwise an error will be returned. 5945** 5946** <b>Security warning:</b> It is recommended that the 5947** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5948** interface. The use of the [sqlite3_enable_load_extension()] interface 5949** should be avoided. This will keep the SQL function [load_extension()] 5950** disabled and prevent SQL injections from giving attackers 5951** access to extension loading capabilities. 5952** 5953** See also the [load_extension() SQL function]. 5954*/ 5955int sqlite3_load_extension( 5956 sqlite3 *db, /* Load the extension into this database connection */ 5957 const char *zFile, /* Name of the shared library containing extension */ 5958 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5959 char **pzErrMsg /* Put error message here if not 0 */ 5960); 5961 5962/* 5963** CAPI3REF: Enable Or Disable Extension Loading 5964** METHOD: sqlite3 5965** 5966** ^So as not to open security holes in older applications that are 5967** unprepared to deal with [extension loading], and as a means of disabling 5968** [extension loading] while evaluating user-entered SQL, the following API 5969** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5970** 5971** ^Extension loading is off by default. 5972** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5973** to turn extension loading on and call it with onoff==0 to turn 5974** it back off again. 5975** 5976** ^This interface enables or disables both the C-API 5977** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5978** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5979** to enable or disable only the C-API.)^ 5980** 5981** <b>Security warning:</b> It is recommended that extension loading 5982** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5983** rather than this interface, so the [load_extension()] SQL function 5984** remains disabled. This will prevent SQL injections from giving attackers 5985** access to extension loading capabilities. 5986*/ 5987int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5988 5989/* 5990** CAPI3REF: Automatically Load Statically Linked Extensions 5991** 5992** ^This interface causes the xEntryPoint() function to be invoked for 5993** each new [database connection] that is created. The idea here is that 5994** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5995** that is to be automatically loaded into all new database connections. 5996** 5997** ^(Even though the function prototype shows that xEntryPoint() takes 5998** no arguments and returns void, SQLite invokes xEntryPoint() with three 5999** arguments and expects an integer result as if the signature of the 6000** entry point where as follows: 6001** 6002** <blockquote><pre> 6003** int xEntryPoint( 6004** sqlite3 *db, 6005** const char **pzErrMsg, 6006** const struct sqlite3_api_routines *pThunk 6007** ); 6008** </pre></blockquote>)^ 6009** 6010** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6011** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6012** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6013** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6014** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6015** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6016** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6017** 6018** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6019** on the list of automatic extensions is a harmless no-op. ^No entry point 6020** will be called more than once for each database connection that is opened. 6021** 6022** See also: [sqlite3_reset_auto_extension()] 6023** and [sqlite3_cancel_auto_extension()] 6024*/ 6025int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6026 6027/* 6028** CAPI3REF: Cancel Automatic Extension Loading 6029** 6030** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6031** initialization routine X that was registered using a prior call to 6032** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6033** routine returns 1 if initialization routine X was successfully 6034** unregistered and it returns 0 if X was not on the list of initialization 6035** routines. 6036*/ 6037int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6038 6039/* 6040** CAPI3REF: Reset Automatic Extension Loading 6041** 6042** ^This interface disables all automatic extensions previously 6043** registered using [sqlite3_auto_extension()]. 6044*/ 6045void sqlite3_reset_auto_extension(void); 6046 6047/* 6048** The interface to the virtual-table mechanism is currently considered 6049** to be experimental. The interface might change in incompatible ways. 6050** If this is a problem for you, do not use the interface at this time. 6051** 6052** When the virtual-table mechanism stabilizes, we will declare the 6053** interface fixed, support it indefinitely, and remove this comment. 6054*/ 6055 6056/* 6057** Structures used by the virtual table interface 6058*/ 6059typedef struct sqlite3_vtab sqlite3_vtab; 6060typedef struct sqlite3_index_info sqlite3_index_info; 6061typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6062typedef struct sqlite3_module sqlite3_module; 6063 6064/* 6065** CAPI3REF: Virtual Table Object 6066** KEYWORDS: sqlite3_module {virtual table module} 6067** 6068** This structure, sometimes called a "virtual table module", 6069** defines the implementation of a [virtual tables]. 6070** This structure consists mostly of methods for the module. 6071** 6072** ^A virtual table module is created by filling in a persistent 6073** instance of this structure and passing a pointer to that instance 6074** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6075** ^The registration remains valid until it is replaced by a different 6076** module or until the [database connection] closes. The content 6077** of this structure must not change while it is registered with 6078** any database connection. 6079*/ 6080struct sqlite3_module { 6081 int iVersion; 6082 int (*xCreate)(sqlite3*, void *pAux, 6083 int argc, const char *const*argv, 6084 sqlite3_vtab **ppVTab, char**); 6085 int (*xConnect)(sqlite3*, void *pAux, 6086 int argc, const char *const*argv, 6087 sqlite3_vtab **ppVTab, char**); 6088 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6089 int (*xDisconnect)(sqlite3_vtab *pVTab); 6090 int (*xDestroy)(sqlite3_vtab *pVTab); 6091 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6092 int (*xClose)(sqlite3_vtab_cursor*); 6093 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6094 int argc, sqlite3_value **argv); 6095 int (*xNext)(sqlite3_vtab_cursor*); 6096 int (*xEof)(sqlite3_vtab_cursor*); 6097 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6098 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6099 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6100 int (*xBegin)(sqlite3_vtab *pVTab); 6101 int (*xSync)(sqlite3_vtab *pVTab); 6102 int (*xCommit)(sqlite3_vtab *pVTab); 6103 int (*xRollback)(sqlite3_vtab *pVTab); 6104 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6105 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6106 void **ppArg); 6107 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6108 /* The methods above are in version 1 of the sqlite_module object. Those 6109 ** below are for version 2 and greater. */ 6110 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6111 int (*xRelease)(sqlite3_vtab *pVTab, int); 6112 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6113}; 6114 6115/* 6116** CAPI3REF: Virtual Table Indexing Information 6117** KEYWORDS: sqlite3_index_info 6118** 6119** The sqlite3_index_info structure and its substructures is used as part 6120** of the [virtual table] interface to 6121** pass information into and receive the reply from the [xBestIndex] 6122** method of a [virtual table module]. The fields under **Inputs** are the 6123** inputs to xBestIndex and are read-only. xBestIndex inserts its 6124** results into the **Outputs** fields. 6125** 6126** ^(The aConstraint[] array records WHERE clause constraints of the form: 6127** 6128** <blockquote>column OP expr</blockquote> 6129** 6130** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6131** stored in aConstraint[].op using one of the 6132** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6133** ^(The index of the column is stored in 6134** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6135** expr on the right-hand side can be evaluated (and thus the constraint 6136** is usable) and false if it cannot.)^ 6137** 6138** ^The optimizer automatically inverts terms of the form "expr OP column" 6139** and makes other simplifications to the WHERE clause in an attempt to 6140** get as many WHERE clause terms into the form shown above as possible. 6141** ^The aConstraint[] array only reports WHERE clause terms that are 6142** relevant to the particular virtual table being queried. 6143** 6144** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6145** ^Each term of aOrderBy records a column of the ORDER BY clause. 6146** 6147** The colUsed field indicates which columns of the virtual table may be 6148** required by the current scan. Virtual table columns are numbered from 6149** zero in the order in which they appear within the CREATE TABLE statement 6150** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6151** the corresponding bit is set within the colUsed mask if the column may be 6152** required by SQLite. If the table has at least 64 columns and any column 6153** to the right of the first 63 is required, then bit 63 of colUsed is also 6154** set. In other words, column iCol may be required if the expression 6155** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6156** non-zero. 6157** 6158** The [xBestIndex] method must fill aConstraintUsage[] with information 6159** about what parameters to pass to xFilter. ^If argvIndex>0 then 6160** the right-hand side of the corresponding aConstraint[] is evaluated 6161** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6162** is true, then the constraint is assumed to be fully handled by the 6163** virtual table and is not checked again by SQLite.)^ 6164** 6165** ^The idxNum and idxPtr values are recorded and passed into the 6166** [xFilter] method. 6167** ^[sqlite3_free()] is used to free idxPtr if and only if 6168** needToFreeIdxPtr is true. 6169** 6170** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6171** the correct order to satisfy the ORDER BY clause so that no separate 6172** sorting step is required. 6173** 6174** ^The estimatedCost value is an estimate of the cost of a particular 6175** strategy. A cost of N indicates that the cost of the strategy is similar 6176** to a linear scan of an SQLite table with N rows. A cost of log(N) 6177** indicates that the expense of the operation is similar to that of a 6178** binary search on a unique indexed field of an SQLite table with N rows. 6179** 6180** ^The estimatedRows value is an estimate of the number of rows that 6181** will be returned by the strategy. 6182** 6183** The xBestIndex method may optionally populate the idxFlags field with a 6184** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6185** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6186** assumes that the strategy may visit at most one row. 6187** 6188** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6189** SQLite also assumes that if a call to the xUpdate() method is made as 6190** part of the same statement to delete or update a virtual table row and the 6191** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6192** any database changes. In other words, if the xUpdate() returns 6193** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6194** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6195** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6196** the xUpdate method are automatically rolled back by SQLite. 6197** 6198** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6199** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6200** If a virtual table extension is 6201** used with an SQLite version earlier than 3.8.2, the results of attempting 6202** to read or write the estimatedRows field are undefined (but are likely 6203** to included crashing the application). The estimatedRows field should 6204** therefore only be used if [sqlite3_libversion_number()] returns a 6205** value greater than or equal to 3008002. Similarly, the idxFlags field 6206** was added for [version 3.9.0] ([dateof:3.9.0]). 6207** It may therefore only be used if 6208** sqlite3_libversion_number() returns a value greater than or equal to 6209** 3009000. 6210*/ 6211struct sqlite3_index_info { 6212 /* Inputs */ 6213 int nConstraint; /* Number of entries in aConstraint */ 6214 struct sqlite3_index_constraint { 6215 int iColumn; /* Column constrained. -1 for ROWID */ 6216 unsigned char op; /* Constraint operator */ 6217 unsigned char usable; /* True if this constraint is usable */ 6218 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6219 } *aConstraint; /* Table of WHERE clause constraints */ 6220 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6221 struct sqlite3_index_orderby { 6222 int iColumn; /* Column number */ 6223 unsigned char desc; /* True for DESC. False for ASC. */ 6224 } *aOrderBy; /* The ORDER BY clause */ 6225 /* Outputs */ 6226 struct sqlite3_index_constraint_usage { 6227 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6228 unsigned char omit; /* Do not code a test for this constraint */ 6229 } *aConstraintUsage; 6230 int idxNum; /* Number used to identify the index */ 6231 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6232 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6233 int orderByConsumed; /* True if output is already ordered */ 6234 double estimatedCost; /* Estimated cost of using this index */ 6235 /* Fields below are only available in SQLite 3.8.2 and later */ 6236 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6237 /* Fields below are only available in SQLite 3.9.0 and later */ 6238 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6239 /* Fields below are only available in SQLite 3.10.0 and later */ 6240 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6241}; 6242 6243/* 6244** CAPI3REF: Virtual Table Scan Flags 6245*/ 6246#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6247 6248/* 6249** CAPI3REF: Virtual Table Constraint Operator Codes 6250** 6251** These macros defined the allowed values for the 6252** [sqlite3_index_info].aConstraint[].op field. Each value represents 6253** an operator that is part of a constraint term in the wHERE clause of 6254** a query that uses a [virtual table]. 6255*/ 6256#define SQLITE_INDEX_CONSTRAINT_EQ 2 6257#define SQLITE_INDEX_CONSTRAINT_GT 4 6258#define SQLITE_INDEX_CONSTRAINT_LE 8 6259#define SQLITE_INDEX_CONSTRAINT_LT 16 6260#define SQLITE_INDEX_CONSTRAINT_GE 32 6261#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6262#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6263#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6264#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6265#define SQLITE_INDEX_CONSTRAINT_NE 68 6266#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6267#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6268#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6269#define SQLITE_INDEX_CONSTRAINT_IS 72 6270 6271/* 6272** CAPI3REF: Register A Virtual Table Implementation 6273** METHOD: sqlite3 6274** 6275** ^These routines are used to register a new [virtual table module] name. 6276** ^Module names must be registered before 6277** creating a new [virtual table] using the module and before using a 6278** preexisting [virtual table] for the module. 6279** 6280** ^The module name is registered on the [database connection] specified 6281** by the first parameter. ^The name of the module is given by the 6282** second parameter. ^The third parameter is a pointer to 6283** the implementation of the [virtual table module]. ^The fourth 6284** parameter is an arbitrary client data pointer that is passed through 6285** into the [xCreate] and [xConnect] methods of the virtual table module 6286** when a new virtual table is be being created or reinitialized. 6287** 6288** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6289** is a pointer to a destructor for the pClientData. ^SQLite will 6290** invoke the destructor function (if it is not NULL) when SQLite 6291** no longer needs the pClientData pointer. ^The destructor will also 6292** be invoked if the call to sqlite3_create_module_v2() fails. 6293** ^The sqlite3_create_module() 6294** interface is equivalent to sqlite3_create_module_v2() with a NULL 6295** destructor. 6296*/ 6297int sqlite3_create_module( 6298 sqlite3 *db, /* SQLite connection to register module with */ 6299 const char *zName, /* Name of the module */ 6300 const sqlite3_module *p, /* Methods for the module */ 6301 void *pClientData /* Client data for xCreate/xConnect */ 6302); 6303int sqlite3_create_module_v2( 6304 sqlite3 *db, /* SQLite connection to register module with */ 6305 const char *zName, /* Name of the module */ 6306 const sqlite3_module *p, /* Methods for the module */ 6307 void *pClientData, /* Client data for xCreate/xConnect */ 6308 void(*xDestroy)(void*) /* Module destructor function */ 6309); 6310 6311/* 6312** CAPI3REF: Virtual Table Instance Object 6313** KEYWORDS: sqlite3_vtab 6314** 6315** Every [virtual table module] implementation uses a subclass 6316** of this object to describe a particular instance 6317** of the [virtual table]. Each subclass will 6318** be tailored to the specific needs of the module implementation. 6319** The purpose of this superclass is to define certain fields that are 6320** common to all module implementations. 6321** 6322** ^Virtual tables methods can set an error message by assigning a 6323** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6324** take care that any prior string is freed by a call to [sqlite3_free()] 6325** prior to assigning a new string to zErrMsg. ^After the error message 6326** is delivered up to the client application, the string will be automatically 6327** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6328*/ 6329struct sqlite3_vtab { 6330 const sqlite3_module *pModule; /* The module for this virtual table */ 6331 int nRef; /* Number of open cursors */ 6332 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6333 /* Virtual table implementations will typically add additional fields */ 6334}; 6335 6336/* 6337** CAPI3REF: Virtual Table Cursor Object 6338** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6339** 6340** Every [virtual table module] implementation uses a subclass of the 6341** following structure to describe cursors that point into the 6342** [virtual table] and are used 6343** to loop through the virtual table. Cursors are created using the 6344** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6345** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6346** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6347** of the module. Each module implementation will define 6348** the content of a cursor structure to suit its own needs. 6349** 6350** This superclass exists in order to define fields of the cursor that 6351** are common to all implementations. 6352*/ 6353struct sqlite3_vtab_cursor { 6354 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6355 /* Virtual table implementations will typically add additional fields */ 6356}; 6357 6358/* 6359** CAPI3REF: Declare The Schema Of A Virtual Table 6360** 6361** ^The [xCreate] and [xConnect] methods of a 6362** [virtual table module] call this interface 6363** to declare the format (the names and datatypes of the columns) of 6364** the virtual tables they implement. 6365*/ 6366int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6367 6368/* 6369** CAPI3REF: Overload A Function For A Virtual Table 6370** METHOD: sqlite3 6371** 6372** ^(Virtual tables can provide alternative implementations of functions 6373** using the [xFindFunction] method of the [virtual table module]. 6374** But global versions of those functions 6375** must exist in order to be overloaded.)^ 6376** 6377** ^(This API makes sure a global version of a function with a particular 6378** name and number of parameters exists. If no such function exists 6379** before this API is called, a new function is created.)^ ^The implementation 6380** of the new function always causes an exception to be thrown. So 6381** the new function is not good for anything by itself. Its only 6382** purpose is to be a placeholder function that can be overloaded 6383** by a [virtual table]. 6384*/ 6385int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6386 6387/* 6388** The interface to the virtual-table mechanism defined above (back up 6389** to a comment remarkably similar to this one) is currently considered 6390** to be experimental. The interface might change in incompatible ways. 6391** If this is a problem for you, do not use the interface at this time. 6392** 6393** When the virtual-table mechanism stabilizes, we will declare the 6394** interface fixed, support it indefinitely, and remove this comment. 6395*/ 6396 6397/* 6398** CAPI3REF: A Handle To An Open BLOB 6399** KEYWORDS: {BLOB handle} {BLOB handles} 6400** 6401** An instance of this object represents an open BLOB on which 6402** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6403** ^Objects of this type are created by [sqlite3_blob_open()] 6404** and destroyed by [sqlite3_blob_close()]. 6405** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6406** can be used to read or write small subsections of the BLOB. 6407** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6408*/ 6409typedef struct sqlite3_blob sqlite3_blob; 6410 6411/* 6412** CAPI3REF: Open A BLOB For Incremental I/O 6413** METHOD: sqlite3 6414** CONSTRUCTOR: sqlite3_blob 6415** 6416** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6417** in row iRow, column zColumn, table zTable in database zDb; 6418** in other words, the same BLOB that would be selected by: 6419** 6420** <pre> 6421** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6422** </pre>)^ 6423** 6424** ^(Parameter zDb is not the filename that contains the database, but 6425** rather the symbolic name of the database. For attached databases, this is 6426** the name that appears after the AS keyword in the [ATTACH] statement. 6427** For the main database file, the database name is "main". For TEMP 6428** tables, the database name is "temp".)^ 6429** 6430** ^If the flags parameter is non-zero, then the BLOB is opened for read 6431** and write access. ^If the flags parameter is zero, the BLOB is opened for 6432** read-only access. 6433** 6434** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6435** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6436** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6437** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6438** on *ppBlob after this function it returns. 6439** 6440** This function fails with SQLITE_ERROR if any of the following are true: 6441** <ul> 6442** <li> ^(Database zDb does not exist)^, 6443** <li> ^(Table zTable does not exist within database zDb)^, 6444** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6445** <li> ^(Column zColumn does not exist)^, 6446** <li> ^(Row iRow is not present in the table)^, 6447** <li> ^(The specified column of row iRow contains a value that is not 6448** a TEXT or BLOB value)^, 6449** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6450** constraint and the blob is being opened for read/write access)^, 6451** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6452** column zColumn is part of a [child key] definition and the blob is 6453** being opened for read/write access)^. 6454** </ul> 6455** 6456** ^Unless it returns SQLITE_MISUSE, this function sets the 6457** [database connection] error code and message accessible via 6458** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6459** 6460** A BLOB referenced by sqlite3_blob_open() may be read using the 6461** [sqlite3_blob_read()] interface and modified by using 6462** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6463** different row of the same table using the [sqlite3_blob_reopen()] 6464** interface. However, the column, table, or database of a [BLOB handle] 6465** cannot be changed after the [BLOB handle] is opened. 6466** 6467** ^(If the row that a BLOB handle points to is modified by an 6468** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6469** then the BLOB handle is marked as "expired". 6470** This is true if any column of the row is changed, even a column 6471** other than the one the BLOB handle is open on.)^ 6472** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6473** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6474** ^(Changes written into a BLOB prior to the BLOB expiring are not 6475** rolled back by the expiration of the BLOB. Such changes will eventually 6476** commit if the transaction continues to completion.)^ 6477** 6478** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6479** the opened blob. ^The size of a blob may not be changed by this 6480** interface. Use the [UPDATE] SQL command to change the size of a 6481** blob. 6482** 6483** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6484** and the built-in [zeroblob] SQL function may be used to create a 6485** zero-filled blob to read or write using the incremental-blob interface. 6486** 6487** To avoid a resource leak, every open [BLOB handle] should eventually 6488** be released by a call to [sqlite3_blob_close()]. 6489** 6490** See also: [sqlite3_blob_close()], 6491** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6492** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6493*/ 6494int sqlite3_blob_open( 6495 sqlite3*, 6496 const char *zDb, 6497 const char *zTable, 6498 const char *zColumn, 6499 sqlite3_int64 iRow, 6500 int flags, 6501 sqlite3_blob **ppBlob 6502); 6503 6504/* 6505** CAPI3REF: Move a BLOB Handle to a New Row 6506** METHOD: sqlite3_blob 6507** 6508** ^This function is used to move an existing [BLOB handle] so that it points 6509** to a different row of the same database table. ^The new row is identified 6510** by the rowid value passed as the second argument. Only the row can be 6511** changed. ^The database, table and column on which the blob handle is open 6512** remain the same. Moving an existing [BLOB handle] to a new row is 6513** faster than closing the existing handle and opening a new one. 6514** 6515** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6516** it must exist and there must be either a blob or text value stored in 6517** the nominated column.)^ ^If the new row is not present in the table, or if 6518** it does not contain a blob or text value, or if another error occurs, an 6519** SQLite error code is returned and the blob handle is considered aborted. 6520** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6521** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6522** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6523** always returns zero. 6524** 6525** ^This function sets the database handle error code and message. 6526*/ 6527int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6528 6529/* 6530** CAPI3REF: Close A BLOB Handle 6531** DESTRUCTOR: sqlite3_blob 6532** 6533** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6534** unconditionally. Even if this routine returns an error code, the 6535** handle is still closed.)^ 6536** 6537** ^If the blob handle being closed was opened for read-write access, and if 6538** the database is in auto-commit mode and there are no other open read-write 6539** blob handles or active write statements, the current transaction is 6540** committed. ^If an error occurs while committing the transaction, an error 6541** code is returned and the transaction rolled back. 6542** 6543** Calling this function with an argument that is not a NULL pointer or an 6544** open blob handle results in undefined behaviour. ^Calling this routine 6545** with a null pointer (such as would be returned by a failed call to 6546** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6547** is passed a valid open blob handle, the values returned by the 6548** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6549*/ 6550int sqlite3_blob_close(sqlite3_blob *); 6551 6552/* 6553** CAPI3REF: Return The Size Of An Open BLOB 6554** METHOD: sqlite3_blob 6555** 6556** ^Returns the size in bytes of the BLOB accessible via the 6557** successfully opened [BLOB handle] in its only argument. ^The 6558** incremental blob I/O routines can only read or overwriting existing 6559** blob content; they cannot change the size of a blob. 6560** 6561** This routine only works on a [BLOB handle] which has been created 6562** by a prior successful call to [sqlite3_blob_open()] and which has not 6563** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6564** to this routine results in undefined and probably undesirable behavior. 6565*/ 6566int sqlite3_blob_bytes(sqlite3_blob *); 6567 6568/* 6569** CAPI3REF: Read Data From A BLOB Incrementally 6570** METHOD: sqlite3_blob 6571** 6572** ^(This function is used to read data from an open [BLOB handle] into a 6573** caller-supplied buffer. N bytes of data are copied into buffer Z 6574** from the open BLOB, starting at offset iOffset.)^ 6575** 6576** ^If offset iOffset is less than N bytes from the end of the BLOB, 6577** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6578** less than zero, [SQLITE_ERROR] is returned and no data is read. 6579** ^The size of the blob (and hence the maximum value of N+iOffset) 6580** can be determined using the [sqlite3_blob_bytes()] interface. 6581** 6582** ^An attempt to read from an expired [BLOB handle] fails with an 6583** error code of [SQLITE_ABORT]. 6584** 6585** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6586** Otherwise, an [error code] or an [extended error code] is returned.)^ 6587** 6588** This routine only works on a [BLOB handle] which has been created 6589** by a prior successful call to [sqlite3_blob_open()] and which has not 6590** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6591** to this routine results in undefined and probably undesirable behavior. 6592** 6593** See also: [sqlite3_blob_write()]. 6594*/ 6595int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6596 6597/* 6598** CAPI3REF: Write Data Into A BLOB Incrementally 6599** METHOD: sqlite3_blob 6600** 6601** ^(This function is used to write data into an open [BLOB handle] from a 6602** caller-supplied buffer. N bytes of data are copied from the buffer Z 6603** into the open BLOB, starting at offset iOffset.)^ 6604** 6605** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6606** Otherwise, an [error code] or an [extended error code] is returned.)^ 6607** ^Unless SQLITE_MISUSE is returned, this function sets the 6608** [database connection] error code and message accessible via 6609** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6610** 6611** ^If the [BLOB handle] passed as the first argument was not opened for 6612** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6613** this function returns [SQLITE_READONLY]. 6614** 6615** This function may only modify the contents of the BLOB; it is 6616** not possible to increase the size of a BLOB using this API. 6617** ^If offset iOffset is less than N bytes from the end of the BLOB, 6618** [SQLITE_ERROR] is returned and no data is written. The size of the 6619** BLOB (and hence the maximum value of N+iOffset) can be determined 6620** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6621** than zero [SQLITE_ERROR] is returned and no data is written. 6622** 6623** ^An attempt to write to an expired [BLOB handle] fails with an 6624** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6625** before the [BLOB handle] expired are not rolled back by the 6626** expiration of the handle, though of course those changes might 6627** have been overwritten by the statement that expired the BLOB handle 6628** or by other independent statements. 6629** 6630** This routine only works on a [BLOB handle] which has been created 6631** by a prior successful call to [sqlite3_blob_open()] and which has not 6632** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6633** to this routine results in undefined and probably undesirable behavior. 6634** 6635** See also: [sqlite3_blob_read()]. 6636*/ 6637int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6638 6639/* 6640** CAPI3REF: Virtual File System Objects 6641** 6642** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6643** that SQLite uses to interact 6644** with the underlying operating system. Most SQLite builds come with a 6645** single default VFS that is appropriate for the host computer. 6646** New VFSes can be registered and existing VFSes can be unregistered. 6647** The following interfaces are provided. 6648** 6649** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6650** ^Names are case sensitive. 6651** ^Names are zero-terminated UTF-8 strings. 6652** ^If there is no match, a NULL pointer is returned. 6653** ^If zVfsName is NULL then the default VFS is returned. 6654** 6655** ^New VFSes are registered with sqlite3_vfs_register(). 6656** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6657** ^The same VFS can be registered multiple times without injury. 6658** ^To make an existing VFS into the default VFS, register it again 6659** with the makeDflt flag set. If two different VFSes with the 6660** same name are registered, the behavior is undefined. If a 6661** VFS is registered with a name that is NULL or an empty string, 6662** then the behavior is undefined. 6663** 6664** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6665** ^(If the default VFS is unregistered, another VFS is chosen as 6666** the default. The choice for the new VFS is arbitrary.)^ 6667*/ 6668sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6669int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6670int sqlite3_vfs_unregister(sqlite3_vfs*); 6671 6672/* 6673** CAPI3REF: Mutexes 6674** 6675** The SQLite core uses these routines for thread 6676** synchronization. Though they are intended for internal 6677** use by SQLite, code that links against SQLite is 6678** permitted to use any of these routines. 6679** 6680** The SQLite source code contains multiple implementations 6681** of these mutex routines. An appropriate implementation 6682** is selected automatically at compile-time. The following 6683** implementations are available in the SQLite core: 6684** 6685** <ul> 6686** <li> SQLITE_MUTEX_PTHREADS 6687** <li> SQLITE_MUTEX_W32 6688** <li> SQLITE_MUTEX_NOOP 6689** </ul> 6690** 6691** The SQLITE_MUTEX_NOOP implementation is a set of routines 6692** that does no real locking and is appropriate for use in 6693** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6694** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6695** and Windows. 6696** 6697** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6698** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6699** implementation is included with the library. In this case the 6700** application must supply a custom mutex implementation using the 6701** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6702** before calling sqlite3_initialize() or any other public sqlite3_ 6703** function that calls sqlite3_initialize(). 6704** 6705** ^The sqlite3_mutex_alloc() routine allocates a new 6706** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6707** routine returns NULL if it is unable to allocate the requested 6708** mutex. The argument to sqlite3_mutex_alloc() must one of these 6709** integer constants: 6710** 6711** <ul> 6712** <li> SQLITE_MUTEX_FAST 6713** <li> SQLITE_MUTEX_RECURSIVE 6714** <li> SQLITE_MUTEX_STATIC_MASTER 6715** <li> SQLITE_MUTEX_STATIC_MEM 6716** <li> SQLITE_MUTEX_STATIC_OPEN 6717** <li> SQLITE_MUTEX_STATIC_PRNG 6718** <li> SQLITE_MUTEX_STATIC_LRU 6719** <li> SQLITE_MUTEX_STATIC_PMEM 6720** <li> SQLITE_MUTEX_STATIC_APP1 6721** <li> SQLITE_MUTEX_STATIC_APP2 6722** <li> SQLITE_MUTEX_STATIC_APP3 6723** <li> SQLITE_MUTEX_STATIC_VFS1 6724** <li> SQLITE_MUTEX_STATIC_VFS2 6725** <li> SQLITE_MUTEX_STATIC_VFS3 6726** </ul> 6727** 6728** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6729** cause sqlite3_mutex_alloc() to create 6730** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6731** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6732** The mutex implementation does not need to make a distinction 6733** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6734** not want to. SQLite will only request a recursive mutex in 6735** cases where it really needs one. If a faster non-recursive mutex 6736** implementation is available on the host platform, the mutex subsystem 6737** might return such a mutex in response to SQLITE_MUTEX_FAST. 6738** 6739** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6740** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6741** a pointer to a static preexisting mutex. ^Nine static mutexes are 6742** used by the current version of SQLite. Future versions of SQLite 6743** may add additional static mutexes. Static mutexes are for internal 6744** use by SQLite only. Applications that use SQLite mutexes should 6745** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6746** SQLITE_MUTEX_RECURSIVE. 6747** 6748** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6749** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6750** returns a different mutex on every call. ^For the static 6751** mutex types, the same mutex is returned on every call that has 6752** the same type number. 6753** 6754** ^The sqlite3_mutex_free() routine deallocates a previously 6755** allocated dynamic mutex. Attempting to deallocate a static 6756** mutex results in undefined behavior. 6757** 6758** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6759** to enter a mutex. ^If another thread is already within the mutex, 6760** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6761** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6762** upon successful entry. ^(Mutexes created using 6763** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6764** In such cases, the 6765** mutex must be exited an equal number of times before another thread 6766** can enter.)^ If the same thread tries to enter any mutex other 6767** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6768** 6769** ^(Some systems (for example, Windows 95) do not support the operation 6770** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6771** will always return SQLITE_BUSY. The SQLite core only ever uses 6772** sqlite3_mutex_try() as an optimization so this is acceptable 6773** behavior.)^ 6774** 6775** ^The sqlite3_mutex_leave() routine exits a mutex that was 6776** previously entered by the same thread. The behavior 6777** is undefined if the mutex is not currently entered by the 6778** calling thread or is not currently allocated. 6779** 6780** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6781** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6782** behave as no-ops. 6783** 6784** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6785*/ 6786sqlite3_mutex *sqlite3_mutex_alloc(int); 6787void sqlite3_mutex_free(sqlite3_mutex*); 6788void sqlite3_mutex_enter(sqlite3_mutex*); 6789int sqlite3_mutex_try(sqlite3_mutex*); 6790void sqlite3_mutex_leave(sqlite3_mutex*); 6791 6792/* 6793** CAPI3REF: Mutex Methods Object 6794** 6795** An instance of this structure defines the low-level routines 6796** used to allocate and use mutexes. 6797** 6798** Usually, the default mutex implementations provided by SQLite are 6799** sufficient, however the application has the option of substituting a custom 6800** implementation for specialized deployments or systems for which SQLite 6801** does not provide a suitable implementation. In this case, the application 6802** creates and populates an instance of this structure to pass 6803** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6804** Additionally, an instance of this structure can be used as an 6805** output variable when querying the system for the current mutex 6806** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6807** 6808** ^The xMutexInit method defined by this structure is invoked as 6809** part of system initialization by the sqlite3_initialize() function. 6810** ^The xMutexInit routine is called by SQLite exactly once for each 6811** effective call to [sqlite3_initialize()]. 6812** 6813** ^The xMutexEnd method defined by this structure is invoked as 6814** part of system shutdown by the sqlite3_shutdown() function. The 6815** implementation of this method is expected to release all outstanding 6816** resources obtained by the mutex methods implementation, especially 6817** those obtained by the xMutexInit method. ^The xMutexEnd() 6818** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6819** 6820** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6821** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6822** xMutexNotheld) implement the following interfaces (respectively): 6823** 6824** <ul> 6825** <li> [sqlite3_mutex_alloc()] </li> 6826** <li> [sqlite3_mutex_free()] </li> 6827** <li> [sqlite3_mutex_enter()] </li> 6828** <li> [sqlite3_mutex_try()] </li> 6829** <li> [sqlite3_mutex_leave()] </li> 6830** <li> [sqlite3_mutex_held()] </li> 6831** <li> [sqlite3_mutex_notheld()] </li> 6832** </ul>)^ 6833** 6834** The only difference is that the public sqlite3_XXX functions enumerated 6835** above silently ignore any invocations that pass a NULL pointer instead 6836** of a valid mutex handle. The implementations of the methods defined 6837** by this structure are not required to handle this case, the results 6838** of passing a NULL pointer instead of a valid mutex handle are undefined 6839** (i.e. it is acceptable to provide an implementation that segfaults if 6840** it is passed a NULL pointer). 6841** 6842** The xMutexInit() method must be threadsafe. It must be harmless to 6843** invoke xMutexInit() multiple times within the same process and without 6844** intervening calls to xMutexEnd(). Second and subsequent calls to 6845** xMutexInit() must be no-ops. 6846** 6847** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6848** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6849** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6850** memory allocation for a fast or recursive mutex. 6851** 6852** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6853** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6854** If xMutexInit fails in any way, it is expected to clean up after itself 6855** prior to returning. 6856*/ 6857typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6858struct sqlite3_mutex_methods { 6859 int (*xMutexInit)(void); 6860 int (*xMutexEnd)(void); 6861 sqlite3_mutex *(*xMutexAlloc)(int); 6862 void (*xMutexFree)(sqlite3_mutex *); 6863 void (*xMutexEnter)(sqlite3_mutex *); 6864 int (*xMutexTry)(sqlite3_mutex *); 6865 void (*xMutexLeave)(sqlite3_mutex *); 6866 int (*xMutexHeld)(sqlite3_mutex *); 6867 int (*xMutexNotheld)(sqlite3_mutex *); 6868}; 6869 6870/* 6871** CAPI3REF: Mutex Verification Routines 6872** 6873** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6874** are intended for use inside assert() statements. The SQLite core 6875** never uses these routines except inside an assert() and applications 6876** are advised to follow the lead of the core. The SQLite core only 6877** provides implementations for these routines when it is compiled 6878** with the SQLITE_DEBUG flag. External mutex implementations 6879** are only required to provide these routines if SQLITE_DEBUG is 6880** defined and if NDEBUG is not defined. 6881** 6882** These routines should return true if the mutex in their argument 6883** is held or not held, respectively, by the calling thread. 6884** 6885** The implementation is not required to provide versions of these 6886** routines that actually work. If the implementation does not provide working 6887** versions of these routines, it should at least provide stubs that always 6888** return true so that one does not get spurious assertion failures. 6889** 6890** If the argument to sqlite3_mutex_held() is a NULL pointer then 6891** the routine should return 1. This seems counter-intuitive since 6892** clearly the mutex cannot be held if it does not exist. But 6893** the reason the mutex does not exist is because the build is not 6894** using mutexes. And we do not want the assert() containing the 6895** call to sqlite3_mutex_held() to fail, so a non-zero return is 6896** the appropriate thing to do. The sqlite3_mutex_notheld() 6897** interface should also return 1 when given a NULL pointer. 6898*/ 6899#ifndef NDEBUG 6900int sqlite3_mutex_held(sqlite3_mutex*); 6901int sqlite3_mutex_notheld(sqlite3_mutex*); 6902#endif 6903 6904/* 6905** CAPI3REF: Mutex Types 6906** 6907** The [sqlite3_mutex_alloc()] interface takes a single argument 6908** which is one of these integer constants. 6909** 6910** The set of static mutexes may change from one SQLite release to the 6911** next. Applications that override the built-in mutex logic must be 6912** prepared to accommodate additional static mutexes. 6913*/ 6914#define SQLITE_MUTEX_FAST 0 6915#define SQLITE_MUTEX_RECURSIVE 1 6916#define SQLITE_MUTEX_STATIC_MASTER 2 6917#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6918#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6919#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6920#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6921#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6922#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6923#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6924#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6925#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6926#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6927#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6928#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6929#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6930 6931/* 6932** CAPI3REF: Retrieve the mutex for a database connection 6933** METHOD: sqlite3 6934** 6935** ^This interface returns a pointer the [sqlite3_mutex] object that 6936** serializes access to the [database connection] given in the argument 6937** when the [threading mode] is Serialized. 6938** ^If the [threading mode] is Single-thread or Multi-thread then this 6939** routine returns a NULL pointer. 6940*/ 6941sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6942 6943/* 6944** CAPI3REF: Low-Level Control Of Database Files 6945** METHOD: sqlite3 6946** 6947** ^The [sqlite3_file_control()] interface makes a direct call to the 6948** xFileControl method for the [sqlite3_io_methods] object associated 6949** with a particular database identified by the second argument. ^The 6950** name of the database is "main" for the main database or "temp" for the 6951** TEMP database, or the name that appears after the AS keyword for 6952** databases that are added using the [ATTACH] SQL command. 6953** ^A NULL pointer can be used in place of "main" to refer to the 6954** main database file. 6955** ^The third and fourth parameters to this routine 6956** are passed directly through to the second and third parameters of 6957** the xFileControl method. ^The return value of the xFileControl 6958** method becomes the return value of this routine. 6959** 6960** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6961** a pointer to the underlying [sqlite3_file] object to be written into 6962** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6963** case is a short-circuit path which does not actually invoke the 6964** underlying sqlite3_io_methods.xFileControl method. 6965** 6966** ^If the second parameter (zDbName) does not match the name of any 6967** open database file, then SQLITE_ERROR is returned. ^This error 6968** code is not remembered and will not be recalled by [sqlite3_errcode()] 6969** or [sqlite3_errmsg()]. The underlying xFileControl method might 6970** also return SQLITE_ERROR. There is no way to distinguish between 6971** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6972** xFileControl method. 6973** 6974** See also: [SQLITE_FCNTL_LOCKSTATE] 6975*/ 6976int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6977 6978/* 6979** CAPI3REF: Testing Interface 6980** 6981** ^The sqlite3_test_control() interface is used to read out internal 6982** state of SQLite and to inject faults into SQLite for testing 6983** purposes. ^The first parameter is an operation code that determines 6984** the number, meaning, and operation of all subsequent parameters. 6985** 6986** This interface is not for use by applications. It exists solely 6987** for verifying the correct operation of the SQLite library. Depending 6988** on how the SQLite library is compiled, this interface might not exist. 6989** 6990** The details of the operation codes, their meanings, the parameters 6991** they take, and what they do are all subject to change without notice. 6992** Unlike most of the SQLite API, this function is not guaranteed to 6993** operate consistently from one release to the next. 6994*/ 6995int sqlite3_test_control(int op, ...); 6996 6997/* 6998** CAPI3REF: Testing Interface Operation Codes 6999** 7000** These constants are the valid operation code parameters used 7001** as the first argument to [sqlite3_test_control()]. 7002** 7003** These parameters and their meanings are subject to change 7004** without notice. These values are for testing purposes only. 7005** Applications should not use any of these parameters or the 7006** [sqlite3_test_control()] interface. 7007*/ 7008#define SQLITE_TESTCTRL_FIRST 5 7009#define SQLITE_TESTCTRL_PRNG_SAVE 5 7010#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7011#define SQLITE_TESTCTRL_PRNG_RESET 7 7012#define SQLITE_TESTCTRL_BITVEC_TEST 8 7013#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7014#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7015#define SQLITE_TESTCTRL_PENDING_BYTE 11 7016#define SQLITE_TESTCTRL_ASSERT 12 7017#define SQLITE_TESTCTRL_ALWAYS 13 7018#define SQLITE_TESTCTRL_RESERVE 14 7019#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7020#define SQLITE_TESTCTRL_ISKEYWORD 16 7021#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7022#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7023#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7024#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7025#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7026#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7027#define SQLITE_TESTCTRL_BYTEORDER 22 7028#define SQLITE_TESTCTRL_ISINIT 23 7029#define SQLITE_TESTCTRL_SORTER_MMAP 24 7030#define SQLITE_TESTCTRL_IMPOSTER 25 7031#define SQLITE_TESTCTRL_LAST 25 7032 7033/* 7034** CAPI3REF: SQLite Runtime Status 7035** 7036** ^These interfaces are used to retrieve runtime status information 7037** about the performance of SQLite, and optionally to reset various 7038** highwater marks. ^The first argument is an integer code for 7039** the specific parameter to measure. ^(Recognized integer codes 7040** are of the form [status parameters | SQLITE_STATUS_...].)^ 7041** ^The current value of the parameter is returned into *pCurrent. 7042** ^The highest recorded value is returned in *pHighwater. ^If the 7043** resetFlag is true, then the highest record value is reset after 7044** *pHighwater is written. ^(Some parameters do not record the highest 7045** value. For those parameters 7046** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7047** ^(Other parameters record only the highwater mark and not the current 7048** value. For these latter parameters nothing is written into *pCurrent.)^ 7049** 7050** ^The sqlite3_status() and sqlite3_status64() routines return 7051** SQLITE_OK on success and a non-zero [error code] on failure. 7052** 7053** If either the current value or the highwater mark is too large to 7054** be represented by a 32-bit integer, then the values returned by 7055** sqlite3_status() are undefined. 7056** 7057** See also: [sqlite3_db_status()] 7058*/ 7059int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7060int sqlite3_status64( 7061 int op, 7062 sqlite3_int64 *pCurrent, 7063 sqlite3_int64 *pHighwater, 7064 int resetFlag 7065); 7066 7067 7068/* 7069** CAPI3REF: Status Parameters 7070** KEYWORDS: {status parameters} 7071** 7072** These integer constants designate various run-time status parameters 7073** that can be returned by [sqlite3_status()]. 7074** 7075** <dl> 7076** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7077** <dd>This parameter is the current amount of memory checked out 7078** using [sqlite3_malloc()], either directly or indirectly. The 7079** figure includes calls made to [sqlite3_malloc()] by the application 7080** and internal memory usage by the SQLite library. Auxiliary page-cache 7081** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7082** this parameter. The amount returned is the sum of the allocation 7083** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7084** 7085** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7086** <dd>This parameter records the largest memory allocation request 7087** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7088** internal equivalents). Only the value returned in the 7089** *pHighwater parameter to [sqlite3_status()] is of interest. 7090** The value written into the *pCurrent parameter is undefined.</dd>)^ 7091** 7092** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7093** <dd>This parameter records the number of separate memory allocations 7094** currently checked out.</dd>)^ 7095** 7096** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7097** <dd>This parameter returns the number of pages used out of the 7098** [pagecache memory allocator] that was configured using 7099** [SQLITE_CONFIG_PAGECACHE]. The 7100** value returned is in pages, not in bytes.</dd>)^ 7101** 7102** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7103** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7104** <dd>This parameter returns the number of bytes of page cache 7105** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7106** buffer and where forced to overflow to [sqlite3_malloc()]. The 7107** returned value includes allocations that overflowed because they 7108** where too large (they were larger than the "sz" parameter to 7109** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7110** no space was left in the page cache.</dd>)^ 7111** 7112** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7113** <dd>This parameter records the largest memory allocation request 7114** handed to [pagecache memory allocator]. Only the value returned in the 7115** *pHighwater parameter to [sqlite3_status()] is of interest. 7116** The value written into the *pCurrent parameter is undefined.</dd>)^ 7117** 7118** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7119** <dd>No longer used.</dd> 7120** 7121** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7122** <dd>No longer used.</dd> 7123** 7124** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7125** <dd>No longer used.</dd> 7126** 7127** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7128** <dd>The *pHighwater parameter records the deepest parser stack. 7129** The *pCurrent value is undefined. The *pHighwater value is only 7130** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7131** </dl> 7132** 7133** New status parameters may be added from time to time. 7134*/ 7135#define SQLITE_STATUS_MEMORY_USED 0 7136#define SQLITE_STATUS_PAGECACHE_USED 1 7137#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7138#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7139#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7140#define SQLITE_STATUS_MALLOC_SIZE 5 7141#define SQLITE_STATUS_PARSER_STACK 6 7142#define SQLITE_STATUS_PAGECACHE_SIZE 7 7143#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7144#define SQLITE_STATUS_MALLOC_COUNT 9 7145 7146/* 7147** CAPI3REF: Database Connection Status 7148** METHOD: sqlite3 7149** 7150** ^This interface is used to retrieve runtime status information 7151** about a single [database connection]. ^The first argument is the 7152** database connection object to be interrogated. ^The second argument 7153** is an integer constant, taken from the set of 7154** [SQLITE_DBSTATUS options], that 7155** determines the parameter to interrogate. The set of 7156** [SQLITE_DBSTATUS options] is likely 7157** to grow in future releases of SQLite. 7158** 7159** ^The current value of the requested parameter is written into *pCur 7160** and the highest instantaneous value is written into *pHiwtr. ^If 7161** the resetFlg is true, then the highest instantaneous value is 7162** reset back down to the current value. 7163** 7164** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7165** non-zero [error code] on failure. 7166** 7167** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7168*/ 7169int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7170 7171/* 7172** CAPI3REF: Status Parameters for database connections 7173** KEYWORDS: {SQLITE_DBSTATUS options} 7174** 7175** These constants are the available integer "verbs" that can be passed as 7176** the second argument to the [sqlite3_db_status()] interface. 7177** 7178** New verbs may be added in future releases of SQLite. Existing verbs 7179** might be discontinued. Applications should check the return code from 7180** [sqlite3_db_status()] to make sure that the call worked. 7181** The [sqlite3_db_status()] interface will return a non-zero error code 7182** if a discontinued or unsupported verb is invoked. 7183** 7184** <dl> 7185** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7186** <dd>This parameter returns the number of lookaside memory slots currently 7187** checked out.</dd>)^ 7188** 7189** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7190** <dd>This parameter returns the number malloc attempts that were 7191** satisfied using lookaside memory. Only the high-water value is meaningful; 7192** the current value is always zero.)^ 7193** 7194** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7195** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7196** <dd>This parameter returns the number malloc attempts that might have 7197** been satisfied using lookaside memory but failed due to the amount of 7198** memory requested being larger than the lookaside slot size. 7199** Only the high-water value is meaningful; 7200** the current value is always zero.)^ 7201** 7202** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7203** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7204** <dd>This parameter returns the number malloc attempts that might have 7205** been satisfied using lookaside memory but failed due to all lookaside 7206** memory already being in use. 7207** Only the high-water value is meaningful; 7208** the current value is always zero.)^ 7209** 7210** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7211** <dd>This parameter returns the approximate number of bytes of heap 7212** memory used by all pager caches associated with the database connection.)^ 7213** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7214** 7215** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7216** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7217** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7218** pager cache is shared between two or more connections the bytes of heap 7219** memory used by that pager cache is divided evenly between the attached 7220** connections.)^ In other words, if none of the pager caches associated 7221** with the database connection are shared, this request returns the same 7222** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7223** shared, the value returned by this call will be smaller than that returned 7224** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7225** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7226** 7227** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7228** <dd>This parameter returns the approximate number of bytes of heap 7229** memory used to store the schema for all databases associated 7230** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7231** ^The full amount of memory used by the schemas is reported, even if the 7232** schema memory is shared with other database connections due to 7233** [shared cache mode] being enabled. 7234** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7235** 7236** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7237** <dd>This parameter returns the approximate number of bytes of heap 7238** and lookaside memory used by all prepared statements associated with 7239** the database connection.)^ 7240** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7241** </dd> 7242** 7243** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7244** <dd>This parameter returns the number of pager cache hits that have 7245** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7246** is always 0. 7247** </dd> 7248** 7249** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7250** <dd>This parameter returns the number of pager cache misses that have 7251** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7252** is always 0. 7253** </dd> 7254** 7255** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7256** <dd>This parameter returns the number of dirty cache entries that have 7257** been written to disk. Specifically, the number of pages written to the 7258** wal file in wal mode databases, or the number of pages written to the 7259** database file in rollback mode databases. Any pages written as part of 7260** transaction rollback or database recovery operations are not included. 7261** If an IO or other error occurs while writing a page to disk, the effect 7262** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7263** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7264** </dd> 7265** 7266** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7267** <dd>This parameter returns zero for the current value if and only if 7268** all foreign key constraints (deferred or immediate) have been 7269** resolved.)^ ^The highwater mark is always 0. 7270** </dd> 7271** </dl> 7272*/ 7273#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7274#define SQLITE_DBSTATUS_CACHE_USED 1 7275#define SQLITE_DBSTATUS_SCHEMA_USED 2 7276#define SQLITE_DBSTATUS_STMT_USED 3 7277#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7278#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7279#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7280#define SQLITE_DBSTATUS_CACHE_HIT 7 7281#define SQLITE_DBSTATUS_CACHE_MISS 8 7282#define SQLITE_DBSTATUS_CACHE_WRITE 9 7283#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7284#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7285#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7286 7287 7288/* 7289** CAPI3REF: Prepared Statement Status 7290** METHOD: sqlite3_stmt 7291** 7292** ^(Each prepared statement maintains various 7293** [SQLITE_STMTSTATUS counters] that measure the number 7294** of times it has performed specific operations.)^ These counters can 7295** be used to monitor the performance characteristics of the prepared 7296** statements. For example, if the number of table steps greatly exceeds 7297** the number of table searches or result rows, that would tend to indicate 7298** that the prepared statement is using a full table scan rather than 7299** an index. 7300** 7301** ^(This interface is used to retrieve and reset counter values from 7302** a [prepared statement]. The first argument is the prepared statement 7303** object to be interrogated. The second argument 7304** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7305** to be interrogated.)^ 7306** ^The current value of the requested counter is returned. 7307** ^If the resetFlg is true, then the counter is reset to zero after this 7308** interface call returns. 7309** 7310** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7311*/ 7312int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7313 7314/* 7315** CAPI3REF: Status Parameters for prepared statements 7316** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7317** 7318** These preprocessor macros define integer codes that name counter 7319** values associated with the [sqlite3_stmt_status()] interface. 7320** The meanings of the various counters are as follows: 7321** 7322** <dl> 7323** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7324** <dd>^This is the number of times that SQLite has stepped forward in 7325** a table as part of a full table scan. Large numbers for this counter 7326** may indicate opportunities for performance improvement through 7327** careful use of indices.</dd> 7328** 7329** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7330** <dd>^This is the number of sort operations that have occurred. 7331** A non-zero value in this counter may indicate an opportunity to 7332** improvement performance through careful use of indices.</dd> 7333** 7334** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7335** <dd>^This is the number of rows inserted into transient indices that 7336** were created automatically in order to help joins run faster. 7337** A non-zero value in this counter may indicate an opportunity to 7338** improvement performance by adding permanent indices that do not 7339** need to be reinitialized each time the statement is run.</dd> 7340** 7341** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7342** <dd>^This is the number of virtual machine operations executed 7343** by the prepared statement if that number is less than or equal 7344** to 2147483647. The number of virtual machine operations can be 7345** used as a proxy for the total work done by the prepared statement. 7346** If the number of virtual machine operations exceeds 2147483647 7347** then the value returned by this statement status code is undefined. 7348** 7349** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7350** <dd>^This is the number of times that the prepare statement has been 7351** automatically regenerated due to schema changes or change to 7352** [bound parameters] that might affect the query plan. 7353** 7354** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7355** <dd>^This is the number of times that the prepared statement has 7356** been run. A single "run" for the purposes of this counter is one 7357** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7358** The counter is incremented on the first [sqlite3_step()] call of each 7359** cycle. 7360** 7361** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7362** <dd>^This is the approximate number of bytes of heap memory 7363** used to store the prepared statement. ^This value is not actually 7364** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7365** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7366** </dd> 7367** </dl> 7368*/ 7369#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7370#define SQLITE_STMTSTATUS_SORT 2 7371#define SQLITE_STMTSTATUS_AUTOINDEX 3 7372#define SQLITE_STMTSTATUS_VM_STEP 4 7373#define SQLITE_STMTSTATUS_REPREPARE 5 7374#define SQLITE_STMTSTATUS_RUN 6 7375#define SQLITE_STMTSTATUS_MEMUSED 99 7376 7377/* 7378** CAPI3REF: Custom Page Cache Object 7379** 7380** The sqlite3_pcache type is opaque. It is implemented by 7381** the pluggable module. The SQLite core has no knowledge of 7382** its size or internal structure and never deals with the 7383** sqlite3_pcache object except by holding and passing pointers 7384** to the object. 7385** 7386** See [sqlite3_pcache_methods2] for additional information. 7387*/ 7388typedef struct sqlite3_pcache sqlite3_pcache; 7389 7390/* 7391** CAPI3REF: Custom Page Cache Object 7392** 7393** The sqlite3_pcache_page object represents a single page in the 7394** page cache. The page cache will allocate instances of this 7395** object. Various methods of the page cache use pointers to instances 7396** of this object as parameters or as their return value. 7397** 7398** See [sqlite3_pcache_methods2] for additional information. 7399*/ 7400typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7401struct sqlite3_pcache_page { 7402 void *pBuf; /* The content of the page */ 7403 void *pExtra; /* Extra information associated with the page */ 7404}; 7405 7406/* 7407** CAPI3REF: Application Defined Page Cache. 7408** KEYWORDS: {page cache} 7409** 7410** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7411** register an alternative page cache implementation by passing in an 7412** instance of the sqlite3_pcache_methods2 structure.)^ 7413** In many applications, most of the heap memory allocated by 7414** SQLite is used for the page cache. 7415** By implementing a 7416** custom page cache using this API, an application can better control 7417** the amount of memory consumed by SQLite, the way in which 7418** that memory is allocated and released, and the policies used to 7419** determine exactly which parts of a database file are cached and for 7420** how long. 7421** 7422** The alternative page cache mechanism is an 7423** extreme measure that is only needed by the most demanding applications. 7424** The built-in page cache is recommended for most uses. 7425** 7426** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7427** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7428** the application may discard the parameter after the call to 7429** [sqlite3_config()] returns.)^ 7430** 7431** [[the xInit() page cache method]] 7432** ^(The xInit() method is called once for each effective 7433** call to [sqlite3_initialize()])^ 7434** (usually only once during the lifetime of the process). ^(The xInit() 7435** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7436** The intent of the xInit() method is to set up global data structures 7437** required by the custom page cache implementation. 7438** ^(If the xInit() method is NULL, then the 7439** built-in default page cache is used instead of the application defined 7440** page cache.)^ 7441** 7442** [[the xShutdown() page cache method]] 7443** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7444** It can be used to clean up 7445** any outstanding resources before process shutdown, if required. 7446** ^The xShutdown() method may be NULL. 7447** 7448** ^SQLite automatically serializes calls to the xInit method, 7449** so the xInit method need not be threadsafe. ^The 7450** xShutdown method is only called from [sqlite3_shutdown()] so it does 7451** not need to be threadsafe either. All other methods must be threadsafe 7452** in multithreaded applications. 7453** 7454** ^SQLite will never invoke xInit() more than once without an intervening 7455** call to xShutdown(). 7456** 7457** [[the xCreate() page cache methods]] 7458** ^SQLite invokes the xCreate() method to construct a new cache instance. 7459** SQLite will typically create one cache instance for each open database file, 7460** though this is not guaranteed. ^The 7461** first parameter, szPage, is the size in bytes of the pages that must 7462** be allocated by the cache. ^szPage will always a power of two. ^The 7463** second parameter szExtra is a number of bytes of extra storage 7464** associated with each page cache entry. ^The szExtra parameter will 7465** a number less than 250. SQLite will use the 7466** extra szExtra bytes on each page to store metadata about the underlying 7467** database page on disk. The value passed into szExtra depends 7468** on the SQLite version, the target platform, and how SQLite was compiled. 7469** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7470** created will be used to cache database pages of a file stored on disk, or 7471** false if it is used for an in-memory database. The cache implementation 7472** does not have to do anything special based with the value of bPurgeable; 7473** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7474** never invoke xUnpin() except to deliberately delete a page. 7475** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7476** false will always have the "discard" flag set to true. 7477** ^Hence, a cache created with bPurgeable false will 7478** never contain any unpinned pages. 7479** 7480** [[the xCachesize() page cache method]] 7481** ^(The xCachesize() method may be called at any time by SQLite to set the 7482** suggested maximum cache-size (number of pages stored by) the cache 7483** instance passed as the first argument. This is the value configured using 7484** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7485** parameter, the implementation is not required to do anything with this 7486** value; it is advisory only. 7487** 7488** [[the xPagecount() page cache methods]] 7489** The xPagecount() method must return the number of pages currently 7490** stored in the cache, both pinned and unpinned. 7491** 7492** [[the xFetch() page cache methods]] 7493** The xFetch() method locates a page in the cache and returns a pointer to 7494** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7495** The pBuf element of the returned sqlite3_pcache_page object will be a 7496** pointer to a buffer of szPage bytes used to store the content of a 7497** single database page. The pExtra element of sqlite3_pcache_page will be 7498** a pointer to the szExtra bytes of extra storage that SQLite has requested 7499** for each entry in the page cache. 7500** 7501** The page to be fetched is determined by the key. ^The minimum key value 7502** is 1. After it has been retrieved using xFetch, the page is considered 7503** to be "pinned". 7504** 7505** If the requested page is already in the page cache, then the page cache 7506** implementation must return a pointer to the page buffer with its content 7507** intact. If the requested page is not already in the cache, then the 7508** cache implementation should use the value of the createFlag 7509** parameter to help it determined what action to take: 7510** 7511** <table border=1 width=85% align=center> 7512** <tr><th> createFlag <th> Behavior when page is not already in cache 7513** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7514** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7515** Otherwise return NULL. 7516** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7517** NULL if allocating a new page is effectively impossible. 7518** </table> 7519** 7520** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7521** will only use a createFlag of 2 after a prior call with a createFlag of 1 7522** failed.)^ In between the to xFetch() calls, SQLite may 7523** attempt to unpin one or more cache pages by spilling the content of 7524** pinned pages to disk and synching the operating system disk cache. 7525** 7526** [[the xUnpin() page cache method]] 7527** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7528** as its second argument. If the third parameter, discard, is non-zero, 7529** then the page must be evicted from the cache. 7530** ^If the discard parameter is 7531** zero, then the page may be discarded or retained at the discretion of 7532** page cache implementation. ^The page cache implementation 7533** may choose to evict unpinned pages at any time. 7534** 7535** The cache must not perform any reference counting. A single 7536** call to xUnpin() unpins the page regardless of the number of prior calls 7537** to xFetch(). 7538** 7539** [[the xRekey() page cache methods]] 7540** The xRekey() method is used to change the key value associated with the 7541** page passed as the second argument. If the cache 7542** previously contains an entry associated with newKey, it must be 7543** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7544** to be pinned. 7545** 7546** When SQLite calls the xTruncate() method, the cache must discard all 7547** existing cache entries with page numbers (keys) greater than or equal 7548** to the value of the iLimit parameter passed to xTruncate(). If any 7549** of these pages are pinned, they are implicitly unpinned, meaning that 7550** they can be safely discarded. 7551** 7552** [[the xDestroy() page cache method]] 7553** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7554** All resources associated with the specified cache should be freed. ^After 7555** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7556** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7557** functions. 7558** 7559** [[the xShrink() page cache method]] 7560** ^SQLite invokes the xShrink() method when it wants the page cache to 7561** free up as much of heap memory as possible. The page cache implementation 7562** is not obligated to free any memory, but well-behaved implementations should 7563** do their best. 7564*/ 7565typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7566struct sqlite3_pcache_methods2 { 7567 int iVersion; 7568 void *pArg; 7569 int (*xInit)(void*); 7570 void (*xShutdown)(void*); 7571 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7572 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7573 int (*xPagecount)(sqlite3_pcache*); 7574 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7575 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7576 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7577 unsigned oldKey, unsigned newKey); 7578 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7579 void (*xDestroy)(sqlite3_pcache*); 7580 void (*xShrink)(sqlite3_pcache*); 7581}; 7582 7583/* 7584** This is the obsolete pcache_methods object that has now been replaced 7585** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7586** retained in the header file for backwards compatibility only. 7587*/ 7588typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7589struct sqlite3_pcache_methods { 7590 void *pArg; 7591 int (*xInit)(void*); 7592 void (*xShutdown)(void*); 7593 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7594 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7595 int (*xPagecount)(sqlite3_pcache*); 7596 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7597 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7598 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7599 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7600 void (*xDestroy)(sqlite3_pcache*); 7601}; 7602 7603 7604/* 7605** CAPI3REF: Online Backup Object 7606** 7607** The sqlite3_backup object records state information about an ongoing 7608** online backup operation. ^The sqlite3_backup object is created by 7609** a call to [sqlite3_backup_init()] and is destroyed by a call to 7610** [sqlite3_backup_finish()]. 7611** 7612** See Also: [Using the SQLite Online Backup API] 7613*/ 7614typedef struct sqlite3_backup sqlite3_backup; 7615 7616/* 7617** CAPI3REF: Online Backup API. 7618** 7619** The backup API copies the content of one database into another. 7620** It is useful either for creating backups of databases or 7621** for copying in-memory databases to or from persistent files. 7622** 7623** See Also: [Using the SQLite Online Backup API] 7624** 7625** ^SQLite holds a write transaction open on the destination database file 7626** for the duration of the backup operation. 7627** ^The source database is read-locked only while it is being read; 7628** it is not locked continuously for the entire backup operation. 7629** ^Thus, the backup may be performed on a live source database without 7630** preventing other database connections from 7631** reading or writing to the source database while the backup is underway. 7632** 7633** ^(To perform a backup operation: 7634** <ol> 7635** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7636** backup, 7637** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7638** the data between the two databases, and finally 7639** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7640** associated with the backup operation. 7641** </ol>)^ 7642** There should be exactly one call to sqlite3_backup_finish() for each 7643** successful call to sqlite3_backup_init(). 7644** 7645** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7646** 7647** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7648** [database connection] associated with the destination database 7649** and the database name, respectively. 7650** ^The database name is "main" for the main database, "temp" for the 7651** temporary database, or the name specified after the AS keyword in 7652** an [ATTACH] statement for an attached database. 7653** ^The S and M arguments passed to 7654** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7655** and database name of the source database, respectively. 7656** ^The source and destination [database connections] (parameters S and D) 7657** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7658** an error. 7659** 7660** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7661** there is already a read or read-write transaction open on the 7662** destination database. 7663** 7664** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7665** returned and an error code and error message are stored in the 7666** destination [database connection] D. 7667** ^The error code and message for the failed call to sqlite3_backup_init() 7668** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7669** [sqlite3_errmsg16()] functions. 7670** ^A successful call to sqlite3_backup_init() returns a pointer to an 7671** [sqlite3_backup] object. 7672** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7673** sqlite3_backup_finish() functions to perform the specified backup 7674** operation. 7675** 7676** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7677** 7678** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7679** the source and destination databases specified by [sqlite3_backup] object B. 7680** ^If N is negative, all remaining source pages are copied. 7681** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7682** are still more pages to be copied, then the function returns [SQLITE_OK]. 7683** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7684** from source to destination, then it returns [SQLITE_DONE]. 7685** ^If an error occurs while running sqlite3_backup_step(B,N), 7686** then an [error code] is returned. ^As well as [SQLITE_OK] and 7687** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7688** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7689** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7690** 7691** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7692** <ol> 7693** <li> the destination database was opened read-only, or 7694** <li> the destination database is using write-ahead-log journaling 7695** and the destination and source page sizes differ, or 7696** <li> the destination database is an in-memory database and the 7697** destination and source page sizes differ. 7698** </ol>)^ 7699** 7700** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7701** the [sqlite3_busy_handler | busy-handler function] 7702** is invoked (if one is specified). ^If the 7703** busy-handler returns non-zero before the lock is available, then 7704** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7705** sqlite3_backup_step() can be retried later. ^If the source 7706** [database connection] 7707** is being used to write to the source database when sqlite3_backup_step() 7708** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7709** case the call to sqlite3_backup_step() can be retried later on. ^(If 7710** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7711** [SQLITE_READONLY] is returned, then 7712** there is no point in retrying the call to sqlite3_backup_step(). These 7713** errors are considered fatal.)^ The application must accept 7714** that the backup operation has failed and pass the backup operation handle 7715** to the sqlite3_backup_finish() to release associated resources. 7716** 7717** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7718** on the destination file. ^The exclusive lock is not released until either 7719** sqlite3_backup_finish() is called or the backup operation is complete 7720** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7721** sqlite3_backup_step() obtains a [shared lock] on the source database that 7722** lasts for the duration of the sqlite3_backup_step() call. 7723** ^Because the source database is not locked between calls to 7724** sqlite3_backup_step(), the source database may be modified mid-way 7725** through the backup process. ^If the source database is modified by an 7726** external process or via a database connection other than the one being 7727** used by the backup operation, then the backup will be automatically 7728** restarted by the next call to sqlite3_backup_step(). ^If the source 7729** database is modified by the using the same database connection as is used 7730** by the backup operation, then the backup database is automatically 7731** updated at the same time. 7732** 7733** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7734** 7735** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7736** application wishes to abandon the backup operation, the application 7737** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7738** ^The sqlite3_backup_finish() interfaces releases all 7739** resources associated with the [sqlite3_backup] object. 7740** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7741** active write-transaction on the destination database is rolled back. 7742** The [sqlite3_backup] object is invalid 7743** and may not be used following a call to sqlite3_backup_finish(). 7744** 7745** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7746** sqlite3_backup_step() errors occurred, regardless or whether or not 7747** sqlite3_backup_step() completed. 7748** ^If an out-of-memory condition or IO error occurred during any prior 7749** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7750** sqlite3_backup_finish() returns the corresponding [error code]. 7751** 7752** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7753** is not a permanent error and does not affect the return value of 7754** sqlite3_backup_finish(). 7755** 7756** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7757** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7758** 7759** ^The sqlite3_backup_remaining() routine returns the number of pages still 7760** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7761** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7762** in the source database at the conclusion of the most recent 7763** sqlite3_backup_step(). 7764** ^(The values returned by these functions are only updated by 7765** sqlite3_backup_step(). If the source database is modified in a way that 7766** changes the size of the source database or the number of pages remaining, 7767** those changes are not reflected in the output of sqlite3_backup_pagecount() 7768** and sqlite3_backup_remaining() until after the next 7769** sqlite3_backup_step().)^ 7770** 7771** <b>Concurrent Usage of Database Handles</b> 7772** 7773** ^The source [database connection] may be used by the application for other 7774** purposes while a backup operation is underway or being initialized. 7775** ^If SQLite is compiled and configured to support threadsafe database 7776** connections, then the source database connection may be used concurrently 7777** from within other threads. 7778** 7779** However, the application must guarantee that the destination 7780** [database connection] is not passed to any other API (by any thread) after 7781** sqlite3_backup_init() is called and before the corresponding call to 7782** sqlite3_backup_finish(). SQLite does not currently check to see 7783** if the application incorrectly accesses the destination [database connection] 7784** and so no error code is reported, but the operations may malfunction 7785** nevertheless. Use of the destination database connection while a 7786** backup is in progress might also also cause a mutex deadlock. 7787** 7788** If running in [shared cache mode], the application must 7789** guarantee that the shared cache used by the destination database 7790** is not accessed while the backup is running. In practice this means 7791** that the application must guarantee that the disk file being 7792** backed up to is not accessed by any connection within the process, 7793** not just the specific connection that was passed to sqlite3_backup_init(). 7794** 7795** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7796** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7797** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7798** APIs are not strictly speaking threadsafe. If they are invoked at the 7799** same time as another thread is invoking sqlite3_backup_step() it is 7800** possible that they return invalid values. 7801*/ 7802sqlite3_backup *sqlite3_backup_init( 7803 sqlite3 *pDest, /* Destination database handle */ 7804 const char *zDestName, /* Destination database name */ 7805 sqlite3 *pSource, /* Source database handle */ 7806 const char *zSourceName /* Source database name */ 7807); 7808int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7809int sqlite3_backup_finish(sqlite3_backup *p); 7810int sqlite3_backup_remaining(sqlite3_backup *p); 7811int sqlite3_backup_pagecount(sqlite3_backup *p); 7812 7813/* 7814** CAPI3REF: Unlock Notification 7815** METHOD: sqlite3 7816** 7817** ^When running in shared-cache mode, a database operation may fail with 7818** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7819** individual tables within the shared-cache cannot be obtained. See 7820** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7821** ^This API may be used to register a callback that SQLite will invoke 7822** when the connection currently holding the required lock relinquishes it. 7823** ^This API is only available if the library was compiled with the 7824** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7825** 7826** See Also: [Using the SQLite Unlock Notification Feature]. 7827** 7828** ^Shared-cache locks are released when a database connection concludes 7829** its current transaction, either by committing it or rolling it back. 7830** 7831** ^When a connection (known as the blocked connection) fails to obtain a 7832** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7833** identity of the database connection (the blocking connection) that 7834** has locked the required resource is stored internally. ^After an 7835** application receives an SQLITE_LOCKED error, it may call the 7836** sqlite3_unlock_notify() method with the blocked connection handle as 7837** the first argument to register for a callback that will be invoked 7838** when the blocking connections current transaction is concluded. ^The 7839** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7840** call that concludes the blocking connections transaction. 7841** 7842** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7843** there is a chance that the blocking connection will have already 7844** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7845** If this happens, then the specified callback is invoked immediately, 7846** from within the call to sqlite3_unlock_notify().)^ 7847** 7848** ^If the blocked connection is attempting to obtain a write-lock on a 7849** shared-cache table, and more than one other connection currently holds 7850** a read-lock on the same table, then SQLite arbitrarily selects one of 7851** the other connections to use as the blocking connection. 7852** 7853** ^(There may be at most one unlock-notify callback registered by a 7854** blocked connection. If sqlite3_unlock_notify() is called when the 7855** blocked connection already has a registered unlock-notify callback, 7856** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7857** called with a NULL pointer as its second argument, then any existing 7858** unlock-notify callback is canceled. ^The blocked connections 7859** unlock-notify callback may also be canceled by closing the blocked 7860** connection using [sqlite3_close()]. 7861** 7862** The unlock-notify callback is not reentrant. If an application invokes 7863** any sqlite3_xxx API functions from within an unlock-notify callback, a 7864** crash or deadlock may be the result. 7865** 7866** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7867** returns SQLITE_OK. 7868** 7869** <b>Callback Invocation Details</b> 7870** 7871** When an unlock-notify callback is registered, the application provides a 7872** single void* pointer that is passed to the callback when it is invoked. 7873** However, the signature of the callback function allows SQLite to pass 7874** it an array of void* context pointers. The first argument passed to 7875** an unlock-notify callback is a pointer to an array of void* pointers, 7876** and the second is the number of entries in the array. 7877** 7878** When a blocking connections transaction is concluded, there may be 7879** more than one blocked connection that has registered for an unlock-notify 7880** callback. ^If two or more such blocked connections have specified the 7881** same callback function, then instead of invoking the callback function 7882** multiple times, it is invoked once with the set of void* context pointers 7883** specified by the blocked connections bundled together into an array. 7884** This gives the application an opportunity to prioritize any actions 7885** related to the set of unblocked database connections. 7886** 7887** <b>Deadlock Detection</b> 7888** 7889** Assuming that after registering for an unlock-notify callback a 7890** database waits for the callback to be issued before taking any further 7891** action (a reasonable assumption), then using this API may cause the 7892** application to deadlock. For example, if connection X is waiting for 7893** connection Y's transaction to be concluded, and similarly connection 7894** Y is waiting on connection X's transaction, then neither connection 7895** will proceed and the system may remain deadlocked indefinitely. 7896** 7897** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7898** detection. ^If a given call to sqlite3_unlock_notify() would put the 7899** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7900** unlock-notify callback is registered. The system is said to be in 7901** a deadlocked state if connection A has registered for an unlock-notify 7902** callback on the conclusion of connection B's transaction, and connection 7903** B has itself registered for an unlock-notify callback when connection 7904** A's transaction is concluded. ^Indirect deadlock is also detected, so 7905** the system is also considered to be deadlocked if connection B has 7906** registered for an unlock-notify callback on the conclusion of connection 7907** C's transaction, where connection C is waiting on connection A. ^Any 7908** number of levels of indirection are allowed. 7909** 7910** <b>The "DROP TABLE" Exception</b> 7911** 7912** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7913** always appropriate to call sqlite3_unlock_notify(). There is however, 7914** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7915** SQLite checks if there are any currently executing SELECT statements 7916** that belong to the same connection. If there are, SQLITE_LOCKED is 7917** returned. In this case there is no "blocking connection", so invoking 7918** sqlite3_unlock_notify() results in the unlock-notify callback being 7919** invoked immediately. If the application then re-attempts the "DROP TABLE" 7920** or "DROP INDEX" query, an infinite loop might be the result. 7921** 7922** One way around this problem is to check the extended error code returned 7923** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7924** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7925** the special "DROP TABLE/INDEX" case, the extended error code is just 7926** SQLITE_LOCKED.)^ 7927*/ 7928int sqlite3_unlock_notify( 7929 sqlite3 *pBlocked, /* Waiting connection */ 7930 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7931 void *pNotifyArg /* Argument to pass to xNotify */ 7932); 7933 7934 7935/* 7936** CAPI3REF: String Comparison 7937** 7938** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7939** and extensions to compare the contents of two buffers containing UTF-8 7940** strings in a case-independent fashion, using the same definition of "case 7941** independence" that SQLite uses internally when comparing identifiers. 7942*/ 7943int sqlite3_stricmp(const char *, const char *); 7944int sqlite3_strnicmp(const char *, const char *, int); 7945 7946/* 7947** CAPI3REF: String Globbing 7948* 7949** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7950** string X matches the [GLOB] pattern P. 7951** ^The definition of [GLOB] pattern matching used in 7952** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7953** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7954** is case sensitive. 7955** 7956** Note that this routine returns zero on a match and non-zero if the strings 7957** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7958** 7959** See also: [sqlite3_strlike()]. 7960*/ 7961int sqlite3_strglob(const char *zGlob, const char *zStr); 7962 7963/* 7964** CAPI3REF: String LIKE Matching 7965* 7966** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7967** string X matches the [LIKE] pattern P with escape character E. 7968** ^The definition of [LIKE] pattern matching used in 7969** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7970** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7971** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7972** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7973** insensitive - equivalent upper and lower case ASCII characters match 7974** one another. 7975** 7976** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7977** only ASCII characters are case folded. 7978** 7979** Note that this routine returns zero on a match and non-zero if the strings 7980** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7981** 7982** See also: [sqlite3_strglob()]. 7983*/ 7984int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7985 7986/* 7987** CAPI3REF: Error Logging Interface 7988** 7989** ^The [sqlite3_log()] interface writes a message into the [error log] 7990** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7991** ^If logging is enabled, the zFormat string and subsequent arguments are 7992** used with [sqlite3_snprintf()] to generate the final output string. 7993** 7994** The sqlite3_log() interface is intended for use by extensions such as 7995** virtual tables, collating functions, and SQL functions. While there is 7996** nothing to prevent an application from calling sqlite3_log(), doing so 7997** is considered bad form. 7998** 7999** The zFormat string must not be NULL. 8000** 8001** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8002** will not use dynamically allocated memory. The log message is stored in 8003** a fixed-length buffer on the stack. If the log message is longer than 8004** a few hundred characters, it will be truncated to the length of the 8005** buffer. 8006*/ 8007void sqlite3_log(int iErrCode, const char *zFormat, ...); 8008 8009/* 8010** CAPI3REF: Write-Ahead Log Commit Hook 8011** METHOD: sqlite3 8012** 8013** ^The [sqlite3_wal_hook()] function is used to register a callback that 8014** is invoked each time data is committed to a database in wal mode. 8015** 8016** ^(The callback is invoked by SQLite after the commit has taken place and 8017** the associated write-lock on the database released)^, so the implementation 8018** may read, write or [checkpoint] the database as required. 8019** 8020** ^The first parameter passed to the callback function when it is invoked 8021** is a copy of the third parameter passed to sqlite3_wal_hook() when 8022** registering the callback. ^The second is a copy of the database handle. 8023** ^The third parameter is the name of the database that was written to - 8024** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8025** is the number of pages currently in the write-ahead log file, 8026** including those that were just committed. 8027** 8028** The callback function should normally return [SQLITE_OK]. ^If an error 8029** code is returned, that error will propagate back up through the 8030** SQLite code base to cause the statement that provoked the callback 8031** to report an error, though the commit will have still occurred. If the 8032** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8033** that does not correspond to any valid SQLite error code, the results 8034** are undefined. 8035** 8036** A single database handle may have at most a single write-ahead log callback 8037** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8038** previously registered write-ahead log callback. ^Note that the 8039** [sqlite3_wal_autocheckpoint()] interface and the 8040** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8041** overwrite any prior [sqlite3_wal_hook()] settings. 8042*/ 8043void *sqlite3_wal_hook( 8044 sqlite3*, 8045 int(*)(void *,sqlite3*,const char*,int), 8046 void* 8047); 8048 8049/* 8050** CAPI3REF: Configure an auto-checkpoint 8051** METHOD: sqlite3 8052** 8053** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8054** [sqlite3_wal_hook()] that causes any database on [database connection] D 8055** to automatically [checkpoint] 8056** after committing a transaction if there are N or 8057** more frames in the [write-ahead log] file. ^Passing zero or 8058** a negative value as the nFrame parameter disables automatic 8059** checkpoints entirely. 8060** 8061** ^The callback registered by this function replaces any existing callback 8062** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8063** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8064** configured by this function. 8065** 8066** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8067** from SQL. 8068** 8069** ^Checkpoints initiated by this mechanism are 8070** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8071** 8072** ^Every new [database connection] defaults to having the auto-checkpoint 8073** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8074** pages. The use of this interface 8075** is only necessary if the default setting is found to be suboptimal 8076** for a particular application. 8077*/ 8078int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8079 8080/* 8081** CAPI3REF: Checkpoint a database 8082** METHOD: sqlite3 8083** 8084** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8085** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8086** 8087** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8088** [write-ahead log] for database X on [database connection] D to be 8089** transferred into the database file and for the write-ahead log to 8090** be reset. See the [checkpointing] documentation for addition 8091** information. 8092** 8093** This interface used to be the only way to cause a checkpoint to 8094** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8095** interface was added. This interface is retained for backwards 8096** compatibility and as a convenience for applications that need to manually 8097** start a callback but which do not need the full power (and corresponding 8098** complication) of [sqlite3_wal_checkpoint_v2()]. 8099*/ 8100int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8101 8102/* 8103** CAPI3REF: Checkpoint a database 8104** METHOD: sqlite3 8105** 8106** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8107** operation on database X of [database connection] D in mode M. Status 8108** information is written back into integers pointed to by L and C.)^ 8109** ^(The M parameter must be a valid [checkpoint mode]:)^ 8110** 8111** <dl> 8112** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8113** ^Checkpoint as many frames as possible without waiting for any database 8114** readers or writers to finish, then sync the database file if all frames 8115** in the log were checkpointed. ^The [busy-handler callback] 8116** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8117** ^On the other hand, passive mode might leave the checkpoint unfinished 8118** if there are concurrent readers or writers. 8119** 8120** <dt>SQLITE_CHECKPOINT_FULL<dd> 8121** ^This mode blocks (it invokes the 8122** [sqlite3_busy_handler|busy-handler callback]) until there is no 8123** database writer and all readers are reading from the most recent database 8124** snapshot. ^It then checkpoints all frames in the log file and syncs the 8125** database file. ^This mode blocks new database writers while it is pending, 8126** but new database readers are allowed to continue unimpeded. 8127** 8128** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8129** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8130** that after checkpointing the log file it blocks (calls the 8131** [busy-handler callback]) 8132** until all readers are reading from the database file only. ^This ensures 8133** that the next writer will restart the log file from the beginning. 8134** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8135** database writer attempts while it is pending, but does not impede readers. 8136** 8137** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8138** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8139** addition that it also truncates the log file to zero bytes just prior 8140** to a successful return. 8141** </dl> 8142** 8143** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8144** the log file or to -1 if the checkpoint could not run because 8145** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8146** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8147** log file (including any that were already checkpointed before the function 8148** was called) or to -1 if the checkpoint could not run due to an error or 8149** because the database is not in WAL mode. ^Note that upon successful 8150** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8151** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8152** 8153** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8154** any other process is running a checkpoint operation at the same time, the 8155** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8156** busy-handler configured, it will not be invoked in this case. 8157** 8158** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8159** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8160** obtained immediately, and a busy-handler is configured, it is invoked and 8161** the writer lock retried until either the busy-handler returns 0 or the lock 8162** is successfully obtained. ^The busy-handler is also invoked while waiting for 8163** database readers as described above. ^If the busy-handler returns 0 before 8164** the writer lock is obtained or while waiting for database readers, the 8165** checkpoint operation proceeds from that point in the same way as 8166** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8167** without blocking any further. ^SQLITE_BUSY is returned in this case. 8168** 8169** ^If parameter zDb is NULL or points to a zero length string, then the 8170** specified operation is attempted on all WAL databases [attached] to 8171** [database connection] db. In this case the 8172** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8173** an SQLITE_BUSY error is encountered when processing one or more of the 8174** attached WAL databases, the operation is still attempted on any remaining 8175** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8176** error occurs while processing an attached database, processing is abandoned 8177** and the error code is returned to the caller immediately. ^If no error 8178** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8179** databases, SQLITE_OK is returned. 8180** 8181** ^If database zDb is the name of an attached database that is not in WAL 8182** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8183** zDb is not NULL (or a zero length string) and is not the name of any 8184** attached database, SQLITE_ERROR is returned to the caller. 8185** 8186** ^Unless it returns SQLITE_MISUSE, 8187** the sqlite3_wal_checkpoint_v2() interface 8188** sets the error information that is queried by 8189** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8190** 8191** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8192** from SQL. 8193*/ 8194int sqlite3_wal_checkpoint_v2( 8195 sqlite3 *db, /* Database handle */ 8196 const char *zDb, /* Name of attached database (or NULL) */ 8197 int eMode, /* SQLITE_CHECKPOINT_* value */ 8198 int *pnLog, /* OUT: Size of WAL log in frames */ 8199 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8200); 8201 8202/* 8203** CAPI3REF: Checkpoint Mode Values 8204** KEYWORDS: {checkpoint mode} 8205** 8206** These constants define all valid values for the "checkpoint mode" passed 8207** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8208** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8209** meaning of each of these checkpoint modes. 8210*/ 8211#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8212#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8213#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8214#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8215 8216/* 8217** CAPI3REF: Virtual Table Interface Configuration 8218** 8219** This function may be called by either the [xConnect] or [xCreate] method 8220** of a [virtual table] implementation to configure 8221** various facets of the virtual table interface. 8222** 8223** If this interface is invoked outside the context of an xConnect or 8224** xCreate virtual table method then the behavior is undefined. 8225** 8226** At present, there is only one option that may be configured using 8227** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8228** may be added in the future. 8229*/ 8230int sqlite3_vtab_config(sqlite3*, int op, ...); 8231 8232/* 8233** CAPI3REF: Virtual Table Configuration Options 8234** 8235** These macros define the various options to the 8236** [sqlite3_vtab_config()] interface that [virtual table] implementations 8237** can use to customize and optimize their behavior. 8238** 8239** <dl> 8240** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8241** <dd>Calls of the form 8242** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8243** where X is an integer. If X is zero, then the [virtual table] whose 8244** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8245** support constraints. In this configuration (which is the default) if 8246** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8247** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8248** specified as part of the users SQL statement, regardless of the actual 8249** ON CONFLICT mode specified. 8250** 8251** If X is non-zero, then the virtual table implementation guarantees 8252** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8253** any modifications to internal or persistent data structures have been made. 8254** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8255** is able to roll back a statement or database transaction, and abandon 8256** or continue processing the current SQL statement as appropriate. 8257** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8258** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8259** had been ABORT. 8260** 8261** Virtual table implementations that are required to handle OR REPLACE 8262** must do so within the [xUpdate] method. If a call to the 8263** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8264** CONFLICT policy is REPLACE, the virtual table implementation should 8265** silently replace the appropriate rows within the xUpdate callback and 8266** return SQLITE_OK. Or, if this is not possible, it may return 8267** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8268** constraint handling. 8269** </dl> 8270*/ 8271#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8272 8273/* 8274** CAPI3REF: Determine The Virtual Table Conflict Policy 8275** 8276** This function may only be called from within a call to the [xUpdate] method 8277** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8278** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8279** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8280** of the SQL statement that triggered the call to the [xUpdate] method of the 8281** [virtual table]. 8282*/ 8283int sqlite3_vtab_on_conflict(sqlite3 *); 8284 8285/* 8286** CAPI3REF: Conflict resolution modes 8287** KEYWORDS: {conflict resolution mode} 8288** 8289** These constants are returned by [sqlite3_vtab_on_conflict()] to 8290** inform a [virtual table] implementation what the [ON CONFLICT] mode 8291** is for the SQL statement being evaluated. 8292** 8293** Note that the [SQLITE_IGNORE] constant is also used as a potential 8294** return value from the [sqlite3_set_authorizer()] callback and that 8295** [SQLITE_ABORT] is also a [result code]. 8296*/ 8297#define SQLITE_ROLLBACK 1 8298/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8299#define SQLITE_FAIL 3 8300/* #define SQLITE_ABORT 4 // Also an error code */ 8301#define SQLITE_REPLACE 5 8302 8303/* 8304** CAPI3REF: Prepared Statement Scan Status Opcodes 8305** KEYWORDS: {scanstatus options} 8306** 8307** The following constants can be used for the T parameter to the 8308** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8309** different metric for sqlite3_stmt_scanstatus() to return. 8310** 8311** When the value returned to V is a string, space to hold that string is 8312** managed by the prepared statement S and will be automatically freed when 8313** S is finalized. 8314** 8315** <dl> 8316** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8317** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8318** set to the total number of times that the X-th loop has run.</dd> 8319** 8320** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8321** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8322** to the total number of rows examined by all iterations of the X-th loop.</dd> 8323** 8324** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8325** <dd>^The "double" variable pointed to by the T parameter will be set to the 8326** query planner's estimate for the average number of rows output from each 8327** iteration of the X-th loop. If the query planner's estimates was accurate, 8328** then this value will approximate the quotient NVISIT/NLOOP and the 8329** product of this value for all prior loops with the same SELECTID will 8330** be the NLOOP value for the current loop. 8331** 8332** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8333** <dd>^The "const char *" variable pointed to by the T parameter will be set 8334** to a zero-terminated UTF-8 string containing the name of the index or table 8335** used for the X-th loop. 8336** 8337** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8338** <dd>^The "const char *" variable pointed to by the T parameter will be set 8339** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8340** description for the X-th loop. 8341** 8342** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8343** <dd>^The "int" variable pointed to by the T parameter will be set to the 8344** "select-id" for the X-th loop. The select-id identifies which query or 8345** subquery the loop is part of. The main query has a select-id of zero. 8346** The select-id is the same value as is output in the first column 8347** of an [EXPLAIN QUERY PLAN] query. 8348** </dl> 8349*/ 8350#define SQLITE_SCANSTAT_NLOOP 0 8351#define SQLITE_SCANSTAT_NVISIT 1 8352#define SQLITE_SCANSTAT_EST 2 8353#define SQLITE_SCANSTAT_NAME 3 8354#define SQLITE_SCANSTAT_EXPLAIN 4 8355#define SQLITE_SCANSTAT_SELECTID 5 8356 8357/* 8358** CAPI3REF: Prepared Statement Scan Status 8359** METHOD: sqlite3_stmt 8360** 8361** This interface returns information about the predicted and measured 8362** performance for pStmt. Advanced applications can use this 8363** interface to compare the predicted and the measured performance and 8364** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8365** 8366** Since this interface is expected to be rarely used, it is only 8367** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8368** compile-time option. 8369** 8370** The "iScanStatusOp" parameter determines which status information to return. 8371** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8372** of this interface is undefined. 8373** ^The requested measurement is written into a variable pointed to by 8374** the "pOut" parameter. 8375** Parameter "idx" identifies the specific loop to retrieve statistics for. 8376** Loops are numbered starting from zero. ^If idx is out of range - less than 8377** zero or greater than or equal to the total number of loops used to implement 8378** the statement - a non-zero value is returned and the variable that pOut 8379** points to is unchanged. 8380** 8381** ^Statistics might not be available for all loops in all statements. ^In cases 8382** where there exist loops with no available statistics, this function behaves 8383** as if the loop did not exist - it returns non-zero and leave the variable 8384** that pOut points to unchanged. 8385** 8386** See also: [sqlite3_stmt_scanstatus_reset()] 8387*/ 8388int sqlite3_stmt_scanstatus( 8389 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8390 int idx, /* Index of loop to report on */ 8391 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8392 void *pOut /* Result written here */ 8393); 8394 8395/* 8396** CAPI3REF: Zero Scan-Status Counters 8397** METHOD: sqlite3_stmt 8398** 8399** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8400** 8401** This API is only available if the library is built with pre-processor 8402** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8403*/ 8404void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8405 8406/* 8407** CAPI3REF: Flush caches to disk mid-transaction 8408** 8409** ^If a write-transaction is open on [database connection] D when the 8410** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8411** pages in the pager-cache that are not currently in use are written out 8412** to disk. A dirty page may be in use if a database cursor created by an 8413** active SQL statement is reading from it, or if it is page 1 of a database 8414** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8415** interface flushes caches for all schemas - "main", "temp", and 8416** any [attached] databases. 8417** 8418** ^If this function needs to obtain extra database locks before dirty pages 8419** can be flushed to disk, it does so. ^If those locks cannot be obtained 8420** immediately and there is a busy-handler callback configured, it is invoked 8421** in the usual manner. ^If the required lock still cannot be obtained, then 8422** the database is skipped and an attempt made to flush any dirty pages 8423** belonging to the next (if any) database. ^If any databases are skipped 8424** because locks cannot be obtained, but no other error occurs, this 8425** function returns SQLITE_BUSY. 8426** 8427** ^If any other error occurs while flushing dirty pages to disk (for 8428** example an IO error or out-of-memory condition), then processing is 8429** abandoned and an SQLite [error code] is returned to the caller immediately. 8430** 8431** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8432** 8433** ^This function does not set the database handle error code or message 8434** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8435*/ 8436int sqlite3_db_cacheflush(sqlite3*); 8437 8438/* 8439** CAPI3REF: The pre-update hook. 8440** 8441** ^These interfaces are only available if SQLite is compiled using the 8442** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8443** 8444** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8445** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8446** on a database table. 8447** ^At most one preupdate hook may be registered at a time on a single 8448** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8449** the previous setting. 8450** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8451** with a NULL pointer as the second parameter. 8452** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8453** the first parameter to callbacks. 8454** 8455** ^The preupdate hook only fires for changes to real database tables; the 8456** preupdate hook is not invoked for changes to [virtual tables] or to 8457** system tables like sqlite_master or sqlite_stat1. 8458** 8459** ^The second parameter to the preupdate callback is a pointer to 8460** the [database connection] that registered the preupdate hook. 8461** ^The third parameter to the preupdate callback is one of the constants 8462** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8463** kind of update operation that is about to occur. 8464** ^(The fourth parameter to the preupdate callback is the name of the 8465** database within the database connection that is being modified. This 8466** will be "main" for the main database or "temp" for TEMP tables or 8467** the name given after the AS keyword in the [ATTACH] statement for attached 8468** databases.)^ 8469** ^The fifth parameter to the preupdate callback is the name of the 8470** table that is being modified. 8471** 8472** For an UPDATE or DELETE operation on a [rowid table], the sixth 8473** parameter passed to the preupdate callback is the initial [rowid] of the 8474** row being modified or deleted. For an INSERT operation on a rowid table, 8475** or any operation on a WITHOUT ROWID table, the value of the sixth 8476** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8477** seventh parameter is the final rowid value of the row being inserted 8478** or updated. The value of the seventh parameter passed to the callback 8479** function is not defined for operations on WITHOUT ROWID tables, or for 8480** INSERT operations on rowid tables. 8481** 8482** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8483** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8484** provide additional information about a preupdate event. These routines 8485** may only be called from within a preupdate callback. Invoking any of 8486** these routines from outside of a preupdate callback or with a 8487** [database connection] pointer that is different from the one supplied 8488** to the preupdate callback results in undefined and probably undesirable 8489** behavior. 8490** 8491** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8492** in the row that is being inserted, updated, or deleted. 8493** 8494** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8495** a [protected sqlite3_value] that contains the value of the Nth column of 8496** the table row before it is updated. The N parameter must be between 0 8497** and one less than the number of columns or the behavior will be 8498** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8499** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8500** behavior is undefined. The [sqlite3_value] that P points to 8501** will be destroyed when the preupdate callback returns. 8502** 8503** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8504** a [protected sqlite3_value] that contains the value of the Nth column of 8505** the table row after it is updated. The N parameter must be between 0 8506** and one less than the number of columns or the behavior will be 8507** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8508** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8509** behavior is undefined. The [sqlite3_value] that P points to 8510** will be destroyed when the preupdate callback returns. 8511** 8512** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8513** callback was invoked as a result of a direct insert, update, or delete 8514** operation; or 1 for inserts, updates, or deletes invoked by top-level 8515** triggers; or 2 for changes resulting from triggers called by top-level 8516** triggers; and so forth. 8517** 8518** See also: [sqlite3_update_hook()] 8519*/ 8520#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8521void *sqlite3_preupdate_hook( 8522 sqlite3 *db, 8523 void(*xPreUpdate)( 8524 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8525 sqlite3 *db, /* Database handle */ 8526 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8527 char const *zDb, /* Database name */ 8528 char const *zName, /* Table name */ 8529 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8530 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8531 ), 8532 void* 8533); 8534int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8535int sqlite3_preupdate_count(sqlite3 *); 8536int sqlite3_preupdate_depth(sqlite3 *); 8537int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8538#endif 8539 8540/* 8541** CAPI3REF: Low-level system error code 8542** 8543** ^Attempt to return the underlying operating system error code or error 8544** number that caused the most recent I/O error or failure to open a file. 8545** The return value is OS-dependent. For example, on unix systems, after 8546** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8547** called to get back the underlying "errno" that caused the problem, such 8548** as ENOSPC, EAUTH, EISDIR, and so forth. 8549*/ 8550int sqlite3_system_errno(sqlite3*); 8551 8552/* 8553** CAPI3REF: Database Snapshot 8554** KEYWORDS: {snapshot} {sqlite3_snapshot} 8555** EXPERIMENTAL 8556** 8557** An instance of the snapshot object records the state of a [WAL mode] 8558** database for some specific point in history. 8559** 8560** In [WAL mode], multiple [database connections] that are open on the 8561** same database file can each be reading a different historical version 8562** of the database file. When a [database connection] begins a read 8563** transaction, that connection sees an unchanging copy of the database 8564** as it existed for the point in time when the transaction first started. 8565** Subsequent changes to the database from other connections are not seen 8566** by the reader until a new read transaction is started. 8567** 8568** The sqlite3_snapshot object records state information about an historical 8569** version of the database file so that it is possible to later open a new read 8570** transaction that sees that historical version of the database rather than 8571** the most recent version. 8572** 8573** The constructor for this object is [sqlite3_snapshot_get()]. The 8574** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8575** to an historical snapshot (if possible). The destructor for 8576** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8577*/ 8578typedef struct sqlite3_snapshot { 8579 unsigned char hidden[48]; 8580} sqlite3_snapshot; 8581 8582/* 8583** CAPI3REF: Record A Database Snapshot 8584** EXPERIMENTAL 8585** 8586** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8587** new [sqlite3_snapshot] object that records the current state of 8588** schema S in database connection D. ^On success, the 8589** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8590** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8591** If there is not already a read-transaction open on schema S when 8592** this function is called, one is opened automatically. 8593** 8594** The following must be true for this function to succeed. If any of 8595** the following statements are false when sqlite3_snapshot_get() is 8596** called, SQLITE_ERROR is returned. The final value of *P is undefined 8597** in this case. 8598** 8599** <ul> 8600** <li> The database handle must be in [autocommit mode]. 8601** 8602** <li> Schema S of [database connection] D must be a [WAL mode] database. 8603** 8604** <li> There must not be a write transaction open on schema S of database 8605** connection D. 8606** 8607** <li> One or more transactions must have been written to the current wal 8608** file since it was created on disk (by any connection). This means 8609** that a snapshot cannot be taken on a wal mode database with no wal 8610** file immediately after it is first opened. At least one transaction 8611** must be written to it first. 8612** </ul> 8613** 8614** This function may also return SQLITE_NOMEM. If it is called with the 8615** database handle in autocommit mode but fails for some other reason, 8616** whether or not a read transaction is opened on schema S is undefined. 8617** 8618** The [sqlite3_snapshot] object returned from a successful call to 8619** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8620** to avoid a memory leak. 8621** 8622** The [sqlite3_snapshot_get()] interface is only available when the 8623** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8624*/ 8625SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8626 sqlite3 *db, 8627 const char *zSchema, 8628 sqlite3_snapshot **ppSnapshot 8629); 8630 8631/* 8632** CAPI3REF: Start a read transaction on an historical snapshot 8633** EXPERIMENTAL 8634** 8635** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8636** read transaction for schema S of 8637** [database connection] D such that the read transaction 8638** refers to historical [snapshot] P, rather than the most 8639** recent change to the database. 8640** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8641** or an appropriate [error code] if it fails. 8642** 8643** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8644** the first operation following the [BEGIN] that takes the schema S 8645** out of [autocommit mode]. 8646** ^In other words, schema S must not currently be in 8647** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8648** database connection D must be out of [autocommit mode]. 8649** ^A [snapshot] will fail to open if it has been overwritten by a 8650** [checkpoint]. 8651** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8652** database connection D does not know that the database file for 8653** schema S is in [WAL mode]. A database connection might not know 8654** that the database file is in [WAL mode] if there has been no prior 8655** I/O on that database connection, or if the database entered [WAL mode] 8656** after the most recent I/O on the database connection.)^ 8657** (Hint: Run "[PRAGMA application_id]" against a newly opened 8658** database connection in order to make it ready to use snapshots.) 8659** 8660** The [sqlite3_snapshot_open()] interface is only available when the 8661** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8662*/ 8663SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8664 sqlite3 *db, 8665 const char *zSchema, 8666 sqlite3_snapshot *pSnapshot 8667); 8668 8669/* 8670** CAPI3REF: Destroy a snapshot 8671** EXPERIMENTAL 8672** 8673** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8674** The application must eventually free every [sqlite3_snapshot] object 8675** using this routine to avoid a memory leak. 8676** 8677** The [sqlite3_snapshot_free()] interface is only available when the 8678** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8679*/ 8680SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8681 8682/* 8683** CAPI3REF: Compare the ages of two snapshot handles. 8684** EXPERIMENTAL 8685** 8686** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8687** of two valid snapshot handles. 8688** 8689** If the two snapshot handles are not associated with the same database 8690** file, the result of the comparison is undefined. 8691** 8692** Additionally, the result of the comparison is only valid if both of the 8693** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8694** last time the wal file was deleted. The wal file is deleted when the 8695** database is changed back to rollback mode or when the number of database 8696** clients drops to zero. If either snapshot handle was obtained before the 8697** wal file was last deleted, the value returned by this function 8698** is undefined. 8699** 8700** Otherwise, this API returns a negative value if P1 refers to an older 8701** snapshot than P2, zero if the two handles refer to the same database 8702** snapshot, and a positive value if P1 is a newer snapshot than P2. 8703*/ 8704SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8705 sqlite3_snapshot *p1, 8706 sqlite3_snapshot *p2 8707); 8708 8709/* 8710** CAPI3REF: Recover snapshots from a wal file 8711** EXPERIMENTAL 8712** 8713** If all connections disconnect from a database file but do not perform 8714** a checkpoint, the existing wal file is opened along with the database 8715** file the next time the database is opened. At this point it is only 8716** possible to successfully call sqlite3_snapshot_open() to open the most 8717** recent snapshot of the database (the one at the head of the wal file), 8718** even though the wal file may contain other valid snapshots for which 8719** clients have sqlite3_snapshot handles. 8720** 8721** This function attempts to scan the wal file associated with database zDb 8722** of database handle db and make all valid snapshots available to 8723** sqlite3_snapshot_open(). It is an error if there is already a read 8724** transaction open on the database, or if the database is not a wal mode 8725** database. 8726** 8727** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8728*/ 8729SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8730 8731/* 8732** Undo the hack that converts floating point types to integer for 8733** builds on processors without floating point support. 8734*/ 8735#ifdef SQLITE_OMIT_FLOATING_POINT 8736# undef double 8737#endif 8738 8739#ifdef __cplusplus 8740} /* End of the 'extern "C"' block */ 8741#endif 8742#endif /* SQLITE3_H */ 8743