1/* 2** 2001-09-15 3** 4** The author disclaims copyright to this source code. In place of 5** a legal notice, here is a blessing: 6** 7** May you do good and not evil. 8** May you find forgiveness for yourself and forgive others. 9** May you share freely, never taking more than you give. 10** 11************************************************************************* 12** This header file defines the interface that the SQLite library 13** presents to client programs. If a C-function, structure, datatype, 14** or constant definition does not appear in this file, then it is 15** not a published API of SQLite, is subject to change without 16** notice, and should not be referenced by programs that use SQLite. 17** 18** Some of the definitions that are in this file are marked as 19** "experimental". Experimental interfaces are normally new 20** features recently added to SQLite. We do not anticipate changes 21** to experimental interfaces but reserve the right to make minor changes 22** if experience from use "in the wild" suggest such changes are prudent. 23** 24** The official C-language API documentation for SQLite is derived 25** from comments in this file. This file is the authoritative source 26** on how SQLite interfaces are supposed to operate. 27** 28** The name of this file under configuration management is "sqlite.h.in". 29** The makefile makes some minor changes to this file (such as inserting 30** the version number) and changes its name to "sqlite3.h" as 31** part of the build process. 32*/ 33#ifndef SQLITE3_H 34#define SQLITE3_H 35#include <stdarg.h> /* Needed for the definition of va_list */ 36 37/* 38** Make sure we can call this stuff from C++. 39*/ 40#ifdef __cplusplus 41extern "C" { 42#endif 43 44 45/* 46** Provide the ability to override linkage features of the interface. 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51#ifndef SQLITE_API 52# define SQLITE_API 53#endif 54#ifndef SQLITE_CDECL 55# define SQLITE_CDECL 56#endif 57#ifndef SQLITE_APICALL 58# define SQLITE_APICALL 59#endif 60#ifndef SQLITE_STDCALL 61# define SQLITE_STDCALL SQLITE_APICALL 62#endif 63#ifndef SQLITE_CALLBACK 64# define SQLITE_CALLBACK 65#endif 66#ifndef SQLITE_SYSAPI 67# define SQLITE_SYSAPI 68#endif 69 70/* 71** These no-op macros are used in front of interfaces to mark those 72** interfaces as either deprecated or experimental. New applications 73** should not use deprecated interfaces - they are supported for backwards 74** compatibility only. Application writers should be aware that 75** experimental interfaces are subject to change in point releases. 76** 77** These macros used to resolve to various kinds of compiler magic that 78** would generate warning messages when they were used. But that 79** compiler magic ended up generating such a flurry of bug reports 80** that we have taken it all out and gone back to using simple 81** noop macros. 82*/ 83#define SQLITE_DEPRECATED 84#define SQLITE_EXPERIMENTAL 85 86/* 87** Ensure these symbols were not defined by some previous header file. 88*/ 89#ifdef SQLITE_VERSION 90# undef SQLITE_VERSION 91#endif 92#ifdef SQLITE_VERSION_NUMBER 93# undef SQLITE_VERSION_NUMBER 94#endif 95 96/* 97** CAPI3REF: Compile-Time Library Version Numbers 98** 99** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 100** evaluates to a string literal that is the SQLite version in the 101** format "X.Y.Z" where X is the major version number (always 3 for 102** SQLite3) and Y is the minor version number and Z is the release number.)^ 103** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 104** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 105** numbers used in [SQLITE_VERSION].)^ 106** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 107** be larger than the release from which it is derived. Either Y will 108** be held constant and Z will be incremented or else Y will be incremented 109** and Z will be reset to zero. 110** 111** Since [version 3.6.18] ([dateof:3.6.18]), 112** SQLite source code has been stored in the 113** <a href="http://www.fossil-scm.org/">Fossil configuration management 114** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 115** a string which identifies a particular check-in of SQLite 116** within its configuration management system. ^The SQLITE_SOURCE_ID 117** string contains the date and time of the check-in (UTC) and a SHA1 118** or SHA3-256 hash of the entire source tree. If the source code has 119** been edited in any way since it was last checked in, then the last 120** four hexadecimal digits of the hash may be modified. 121** 122** See also: [sqlite3_libversion()], 123** [sqlite3_libversion_number()], [sqlite3_sourceid()], 124** [sqlite_version()] and [sqlite_source_id()]. 125*/ 126#define SQLITE_VERSION "--VERS--" 127#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 128#define SQLITE_SOURCE_ID "--SOURCE-ID--" 129 130/* 131** CAPI3REF: Run-Time Library Version Numbers 132** KEYWORDS: sqlite3_version sqlite3_sourceid 133** 134** These interfaces provide the same information as the [SQLITE_VERSION], 135** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 136** but are associated with the library instead of the header file. ^(Cautious 137** programmers might include assert() statements in their application to 138** verify that values returned by these interfaces match the macros in 139** the header, and thus ensure that the application is 140** compiled with matching library and header files. 141** 142** <blockquote><pre> 143** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 144** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 ); 145** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 146** </pre></blockquote>)^ 147** 148** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 149** macro. ^The sqlite3_libversion() function returns a pointer to the 150** to the sqlite3_version[] string constant. The sqlite3_libversion() 151** function is provided for use in DLLs since DLL users usually do not have 152** direct access to string constants within the DLL. ^The 153** sqlite3_libversion_number() function returns an integer equal to 154** [SQLITE_VERSION_NUMBER]. ^(The sqlite3_sourceid() function returns 155** a pointer to a string constant whose value is the same as the 156** [SQLITE_SOURCE_ID] C preprocessor macro. Except if SQLite is built 157** using an edited copy of [the amalgamation], then the last four characters 158** of the hash might be different from [SQLITE_SOURCE_ID].)^ 159** 160** See also: [sqlite_version()] and [sqlite_source_id()]. 161*/ 162SQLITE_EXTERN const char sqlite3_version[]; 163const char *sqlite3_libversion(void); 164const char *sqlite3_sourceid(void); 165int sqlite3_libversion_number(void); 166 167/* 168** CAPI3REF: Run-Time Library Compilation Options Diagnostics 169** 170** ^The sqlite3_compileoption_used() function returns 0 or 1 171** indicating whether the specified option was defined at 172** compile time. ^The SQLITE_ prefix may be omitted from the 173** option name passed to sqlite3_compileoption_used(). 174** 175** ^The sqlite3_compileoption_get() function allows iterating 176** over the list of options that were defined at compile time by 177** returning the N-th compile time option string. ^If N is out of range, 178** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 179** prefix is omitted from any strings returned by 180** sqlite3_compileoption_get(). 181** 182** ^Support for the diagnostic functions sqlite3_compileoption_used() 183** and sqlite3_compileoption_get() may be omitted by specifying the 184** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 185** 186** See also: SQL functions [sqlite_compileoption_used()] and 187** [sqlite_compileoption_get()] and the [compile_options pragma]. 188*/ 189#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 190int sqlite3_compileoption_used(const char *zOptName); 191const char *sqlite3_compileoption_get(int N); 192#endif 193 194/* 195** CAPI3REF: Test To See If The Library Is Threadsafe 196** 197** ^The sqlite3_threadsafe() function returns zero if and only if 198** SQLite was compiled with mutexing code omitted due to the 199** [SQLITE_THREADSAFE] compile-time option being set to 0. 200** 201** SQLite can be compiled with or without mutexes. When 202** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 203** are enabled and SQLite is threadsafe. When the 204** [SQLITE_THREADSAFE] macro is 0, 205** the mutexes are omitted. Without the mutexes, it is not safe 206** to use SQLite concurrently from more than one thread. 207** 208** Enabling mutexes incurs a measurable performance penalty. 209** So if speed is of utmost importance, it makes sense to disable 210** the mutexes. But for maximum safety, mutexes should be enabled. 211** ^The default behavior is for mutexes to be enabled. 212** 213** This interface can be used by an application to make sure that the 214** version of SQLite that it is linking against was compiled with 215** the desired setting of the [SQLITE_THREADSAFE] macro. 216** 217** This interface only reports on the compile-time mutex setting 218** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 219** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 220** can be fully or partially disabled using a call to [sqlite3_config()] 221** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 222** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 223** sqlite3_threadsafe() function shows only the compile-time setting of 224** thread safety, not any run-time changes to that setting made by 225** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 226** is unchanged by calls to sqlite3_config().)^ 227** 228** See the [threading mode] documentation for additional information. 229*/ 230int sqlite3_threadsafe(void); 231 232/* 233** CAPI3REF: Database Connection Handle 234** KEYWORDS: {database connection} {database connections} 235** 236** Each open SQLite database is represented by a pointer to an instance of 237** the opaque structure named "sqlite3". It is useful to think of an sqlite3 238** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 239** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 240** and [sqlite3_close_v2()] are its destructors. There are many other 241** interfaces (such as 242** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 243** [sqlite3_busy_timeout()] to name but three) that are methods on an 244** sqlite3 object. 245*/ 246typedef struct sqlite3 sqlite3; 247 248/* 249** CAPI3REF: 64-Bit Integer Types 250** KEYWORDS: sqlite_int64 sqlite_uint64 251** 252** Because there is no cross-platform way to specify 64-bit integer types 253** SQLite includes typedefs for 64-bit signed and unsigned integers. 254** 255** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 256** The sqlite_int64 and sqlite_uint64 types are supported for backwards 257** compatibility only. 258** 259** ^The sqlite3_int64 and sqlite_int64 types can store integer values 260** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 261** sqlite3_uint64 and sqlite_uint64 types can store integer values 262** between 0 and +18446744073709551615 inclusive. 263*/ 264#ifdef SQLITE_INT64_TYPE 265 typedef SQLITE_INT64_TYPE sqlite_int64; 266# ifdef SQLITE_UINT64_TYPE 267 typedef SQLITE_UINT64_TYPE sqlite_uint64; 268# else 269 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 270# endif 271#elif defined(_MSC_VER) || defined(__BORLANDC__) 272 typedef __int64 sqlite_int64; 273 typedef unsigned __int64 sqlite_uint64; 274#else 275 typedef long long int sqlite_int64; 276 typedef unsigned long long int sqlite_uint64; 277#endif 278typedef sqlite_int64 sqlite3_int64; 279typedef sqlite_uint64 sqlite3_uint64; 280 281/* 282** If compiling for a processor that lacks floating point support, 283** substitute integer for floating-point. 284*/ 285#ifdef SQLITE_OMIT_FLOATING_POINT 286# define double sqlite3_int64 287#endif 288 289/* 290** CAPI3REF: Closing A Database Connection 291** DESTRUCTOR: sqlite3 292** 293** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 294** for the [sqlite3] object. 295** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 296** the [sqlite3] object is successfully destroyed and all associated 297** resources are deallocated. 298** 299** ^If the database connection is associated with unfinalized prepared 300** statements or unfinished sqlite3_backup objects then sqlite3_close() 301** will leave the database connection open and return [SQLITE_BUSY]. 302** ^If sqlite3_close_v2() is called with unfinalized prepared statements 303** and/or unfinished sqlite3_backups, then the database connection becomes 304** an unusable "zombie" which will automatically be deallocated when the 305** last prepared statement is finalized or the last sqlite3_backup is 306** finished. The sqlite3_close_v2() interface is intended for use with 307** host languages that are garbage collected, and where the order in which 308** destructors are called is arbitrary. 309** 310** Applications should [sqlite3_finalize | finalize] all [prepared statements], 311** [sqlite3_blob_close | close] all [BLOB handles], and 312** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 313** with the [sqlite3] object prior to attempting to close the object. ^If 314** sqlite3_close_v2() is called on a [database connection] that still has 315** outstanding [prepared statements], [BLOB handles], and/or 316** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 317** of resources is deferred until all [prepared statements], [BLOB handles], 318** and [sqlite3_backup] objects are also destroyed. 319** 320** ^If an [sqlite3] object is destroyed while a transaction is open, 321** the transaction is automatically rolled back. 322** 323** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 324** must be either a NULL 325** pointer or an [sqlite3] object pointer obtained 326** from [sqlite3_open()], [sqlite3_open16()], or 327** [sqlite3_open_v2()], and not previously closed. 328** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 329** argument is a harmless no-op. 330*/ 331int sqlite3_close(sqlite3*); 332int sqlite3_close_v2(sqlite3*); 333 334/* 335** The type for a callback function. 336** This is legacy and deprecated. It is included for historical 337** compatibility and is not documented. 338*/ 339typedef int (*sqlite3_callback)(void*,int,char**, char**); 340 341/* 342** CAPI3REF: One-Step Query Execution Interface 343** METHOD: sqlite3 344** 345** The sqlite3_exec() interface is a convenience wrapper around 346** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 347** that allows an application to run multiple statements of SQL 348** without having to use a lot of C code. 349** 350** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 351** semicolon-separate SQL statements passed into its 2nd argument, 352** in the context of the [database connection] passed in as its 1st 353** argument. ^If the callback function of the 3rd argument to 354** sqlite3_exec() is not NULL, then it is invoked for each result row 355** coming out of the evaluated SQL statements. ^The 4th argument to 356** sqlite3_exec() is relayed through to the 1st argument of each 357** callback invocation. ^If the callback pointer to sqlite3_exec() 358** is NULL, then no callback is ever invoked and result rows are 359** ignored. 360** 361** ^If an error occurs while evaluating the SQL statements passed into 362** sqlite3_exec(), then execution of the current statement stops and 363** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 364** is not NULL then any error message is written into memory obtained 365** from [sqlite3_malloc()] and passed back through the 5th parameter. 366** To avoid memory leaks, the application should invoke [sqlite3_free()] 367** on error message strings returned through the 5th parameter of 368** sqlite3_exec() after the error message string is no longer needed. 369** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 370** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 371** NULL before returning. 372** 373** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 374** routine returns SQLITE_ABORT without invoking the callback again and 375** without running any subsequent SQL statements. 376** 377** ^The 2nd argument to the sqlite3_exec() callback function is the 378** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 379** callback is an array of pointers to strings obtained as if from 380** [sqlite3_column_text()], one for each column. ^If an element of a 381** result row is NULL then the corresponding string pointer for the 382** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 383** sqlite3_exec() callback is an array of pointers to strings where each 384** entry represents the name of corresponding result column as obtained 385** from [sqlite3_column_name()]. 386** 387** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 388** to an empty string, or a pointer that contains only whitespace and/or 389** SQL comments, then no SQL statements are evaluated and the database 390** is not changed. 391** 392** Restrictions: 393** 394** <ul> 395** <li> The application must ensure that the 1st parameter to sqlite3_exec() 396** is a valid and open [database connection]. 397** <li> The application must not close the [database connection] specified by 398** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 399** <li> The application must not modify the SQL statement text passed into 400** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 401** </ul> 402*/ 403int sqlite3_exec( 404 sqlite3*, /* An open database */ 405 const char *sql, /* SQL to be evaluated */ 406 int (*callback)(void*,int,char**,char**), /* Callback function */ 407 void *, /* 1st argument to callback */ 408 char **errmsg /* Error msg written here */ 409); 410 411/* 412** CAPI3REF: Result Codes 413** KEYWORDS: {result code definitions} 414** 415** Many SQLite functions return an integer result code from the set shown 416** here in order to indicate success or failure. 417** 418** New error codes may be added in future versions of SQLite. 419** 420** See also: [extended result code definitions] 421*/ 422#define SQLITE_OK 0 /* Successful result */ 423/* beginning-of-error-codes */ 424#define SQLITE_ERROR 1 /* Generic error */ 425#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 426#define SQLITE_PERM 3 /* Access permission denied */ 427#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 428#define SQLITE_BUSY 5 /* The database file is locked */ 429#define SQLITE_LOCKED 6 /* A table in the database is locked */ 430#define SQLITE_NOMEM 7 /* A malloc() failed */ 431#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 432#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 433#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 434#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 435#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 436#define SQLITE_FULL 13 /* Insertion failed because database is full */ 437#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 438#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 439#define SQLITE_EMPTY 16 /* Internal use only */ 440#define SQLITE_SCHEMA 17 /* The database schema changed */ 441#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 442#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 443#define SQLITE_MISMATCH 20 /* Data type mismatch */ 444#define SQLITE_MISUSE 21 /* Library used incorrectly */ 445#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 446#define SQLITE_AUTH 23 /* Authorization denied */ 447#define SQLITE_FORMAT 24 /* Not used */ 448#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 449#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 450#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 451#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 452#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 453#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 454/* end-of-error-codes */ 455 456/* 457** CAPI3REF: Extended Result Codes 458** KEYWORDS: {extended result code definitions} 459** 460** In its default configuration, SQLite API routines return one of 30 integer 461** [result codes]. However, experience has shown that many of 462** these result codes are too coarse-grained. They do not provide as 463** much information about problems as programmers might like. In an effort to 464** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 465** and later) include 466** support for additional result codes that provide more detailed information 467** about errors. These [extended result codes] are enabled or disabled 468** on a per database connection basis using the 469** [sqlite3_extended_result_codes()] API. Or, the extended code for 470** the most recent error can be obtained using 471** [sqlite3_extended_errcode()]. 472*/ 473#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 474#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 475#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 476#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 477#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 478#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 479#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 480#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 481#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 482#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 483#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 484#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 485#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 486#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 487#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 488#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 489#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 490#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 491#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 492#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 493#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 494#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 495#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 496#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 497#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 498#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 499#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 500#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 501#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 502#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 503#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 504#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 505#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 506#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 507#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 508#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 509#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 510#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 511#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 512#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 513#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) 514#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 515#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 516#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 517#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 518#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 519#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 520#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 521#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 522#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 523#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 524#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 525#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 526#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 527#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 528#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 529#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 530#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 531#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 532#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 533#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 534#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 535#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 536 537/* 538** CAPI3REF: Flags For File Open Operations 539** 540** These bit values are intended for use in the 541** 3rd parameter to the [sqlite3_open_v2()] interface and 542** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 543*/ 544#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 545#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 546#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 547#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 548#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 549#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 550#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 551#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 552#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 553#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 554#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 555#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 556#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 557#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 558#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 559#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 560#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 561#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 562#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 563#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 564 565/* Reserved: 0x00F00000 */ 566 567/* 568** CAPI3REF: Device Characteristics 569** 570** The xDeviceCharacteristics method of the [sqlite3_io_methods] 571** object returns an integer which is a vector of these 572** bit values expressing I/O characteristics of the mass storage 573** device that holds the file that the [sqlite3_io_methods] 574** refers to. 575** 576** The SQLITE_IOCAP_ATOMIC property means that all writes of 577** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 578** mean that writes of blocks that are nnn bytes in size and 579** are aligned to an address which is an integer multiple of 580** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 581** that when data is appended to a file, the data is appended 582** first then the size of the file is extended, never the other 583** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 584** information is written to disk in the same order as calls 585** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 586** after reboot following a crash or power loss, the only bytes in a 587** file that were written at the application level might have changed 588** and that adjacent bytes, even bytes within the same sector are 589** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 590** flag indicates that a file cannot be deleted when open. The 591** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 592** read-only media and cannot be changed even by processes with 593** elevated privileges. 594** 595** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 596** filesystem supports doing multiple write operations atomically when those 597** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 598** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 599*/ 600#define SQLITE_IOCAP_ATOMIC 0x00000001 601#define SQLITE_IOCAP_ATOMIC512 0x00000002 602#define SQLITE_IOCAP_ATOMIC1K 0x00000004 603#define SQLITE_IOCAP_ATOMIC2K 0x00000008 604#define SQLITE_IOCAP_ATOMIC4K 0x00000010 605#define SQLITE_IOCAP_ATOMIC8K 0x00000020 606#define SQLITE_IOCAP_ATOMIC16K 0x00000040 607#define SQLITE_IOCAP_ATOMIC32K 0x00000080 608#define SQLITE_IOCAP_ATOMIC64K 0x00000100 609#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 610#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 611#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 612#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 613#define SQLITE_IOCAP_IMMUTABLE 0x00002000 614#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 615 616/* 617** CAPI3REF: File Locking Levels 618** 619** SQLite uses one of these integer values as the second 620** argument to calls it makes to the xLock() and xUnlock() methods 621** of an [sqlite3_io_methods] object. 622*/ 623#define SQLITE_LOCK_NONE 0 624#define SQLITE_LOCK_SHARED 1 625#define SQLITE_LOCK_RESERVED 2 626#define SQLITE_LOCK_PENDING 3 627#define SQLITE_LOCK_EXCLUSIVE 4 628 629/* 630** CAPI3REF: Synchronization Type Flags 631** 632** When SQLite invokes the xSync() method of an 633** [sqlite3_io_methods] object it uses a combination of 634** these integer values as the second argument. 635** 636** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 637** sync operation only needs to flush data to mass storage. Inode 638** information need not be flushed. If the lower four bits of the flag 639** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 640** If the lower four bits equal SQLITE_SYNC_FULL, that means 641** to use Mac OS X style fullsync instead of fsync(). 642** 643** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 644** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 645** settings. The [synchronous pragma] determines when calls to the 646** xSync VFS method occur and applies uniformly across all platforms. 647** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 648** energetic or rigorous or forceful the sync operations are and 649** only make a difference on Mac OSX for the default SQLite code. 650** (Third-party VFS implementations might also make the distinction 651** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 652** operating systems natively supported by SQLite, only Mac OSX 653** cares about the difference.) 654*/ 655#define SQLITE_SYNC_NORMAL 0x00002 656#define SQLITE_SYNC_FULL 0x00003 657#define SQLITE_SYNC_DATAONLY 0x00010 658 659/* 660** CAPI3REF: OS Interface Open File Handle 661** 662** An [sqlite3_file] object represents an open file in the 663** [sqlite3_vfs | OS interface layer]. Individual OS interface 664** implementations will 665** want to subclass this object by appending additional fields 666** for their own use. The pMethods entry is a pointer to an 667** [sqlite3_io_methods] object that defines methods for performing 668** I/O operations on the open file. 669*/ 670typedef struct sqlite3_file sqlite3_file; 671struct sqlite3_file { 672 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 673}; 674 675/* 676** CAPI3REF: OS Interface File Virtual Methods Object 677** 678** Every file opened by the [sqlite3_vfs.xOpen] method populates an 679** [sqlite3_file] object (or, more commonly, a subclass of the 680** [sqlite3_file] object) with a pointer to an instance of this object. 681** This object defines the methods used to perform various operations 682** against the open file represented by the [sqlite3_file] object. 683** 684** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 685** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 686** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 687** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 688** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 689** to NULL. 690** 691** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 692** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 693** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 694** flag may be ORed in to indicate that only the data of the file 695** and not its inode needs to be synced. 696** 697** The integer values to xLock() and xUnlock() are one of 698** <ul> 699** <li> [SQLITE_LOCK_NONE], 700** <li> [SQLITE_LOCK_SHARED], 701** <li> [SQLITE_LOCK_RESERVED], 702** <li> [SQLITE_LOCK_PENDING], or 703** <li> [SQLITE_LOCK_EXCLUSIVE]. 704** </ul> 705** xLock() increases the lock. xUnlock() decreases the lock. 706** The xCheckReservedLock() method checks whether any database connection, 707** either in this process or in some other process, is holding a RESERVED, 708** PENDING, or EXCLUSIVE lock on the file. It returns true 709** if such a lock exists and false otherwise. 710** 711** The xFileControl() method is a generic interface that allows custom 712** VFS implementations to directly control an open file using the 713** [sqlite3_file_control()] interface. The second "op" argument is an 714** integer opcode. The third argument is a generic pointer intended to 715** point to a structure that may contain arguments or space in which to 716** write return values. Potential uses for xFileControl() might be 717** functions to enable blocking locks with timeouts, to change the 718** locking strategy (for example to use dot-file locks), to inquire 719** about the status of a lock, or to break stale locks. The SQLite 720** core reserves all opcodes less than 100 for its own use. 721** A [file control opcodes | list of opcodes] less than 100 is available. 722** Applications that define a custom xFileControl method should use opcodes 723** greater than 100 to avoid conflicts. VFS implementations should 724** return [SQLITE_NOTFOUND] for file control opcodes that they do not 725** recognize. 726** 727** The xSectorSize() method returns the sector size of the 728** device that underlies the file. The sector size is the 729** minimum write that can be performed without disturbing 730** other bytes in the file. The xDeviceCharacteristics() 731** method returns a bit vector describing behaviors of the 732** underlying device: 733** 734** <ul> 735** <li> [SQLITE_IOCAP_ATOMIC] 736** <li> [SQLITE_IOCAP_ATOMIC512] 737** <li> [SQLITE_IOCAP_ATOMIC1K] 738** <li> [SQLITE_IOCAP_ATOMIC2K] 739** <li> [SQLITE_IOCAP_ATOMIC4K] 740** <li> [SQLITE_IOCAP_ATOMIC8K] 741** <li> [SQLITE_IOCAP_ATOMIC16K] 742** <li> [SQLITE_IOCAP_ATOMIC32K] 743** <li> [SQLITE_IOCAP_ATOMIC64K] 744** <li> [SQLITE_IOCAP_SAFE_APPEND] 745** <li> [SQLITE_IOCAP_SEQUENTIAL] 746** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 747** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 748** <li> [SQLITE_IOCAP_IMMUTABLE] 749** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 750** </ul> 751** 752** The SQLITE_IOCAP_ATOMIC property means that all writes of 753** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 754** mean that writes of blocks that are nnn bytes in size and 755** are aligned to an address which is an integer multiple of 756** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 757** that when data is appended to a file, the data is appended 758** first then the size of the file is extended, never the other 759** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 760** information is written to disk in the same order as calls 761** to xWrite(). 762** 763** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 764** in the unread portions of the buffer with zeros. A VFS that 765** fails to zero-fill short reads might seem to work. However, 766** failure to zero-fill short reads will eventually lead to 767** database corruption. 768*/ 769typedef struct sqlite3_io_methods sqlite3_io_methods; 770struct sqlite3_io_methods { 771 int iVersion; 772 int (*xClose)(sqlite3_file*); 773 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 774 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 775 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 776 int (*xSync)(sqlite3_file*, int flags); 777 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 778 int (*xLock)(sqlite3_file*, int); 779 int (*xUnlock)(sqlite3_file*, int); 780 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 781 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 782 int (*xSectorSize)(sqlite3_file*); 783 int (*xDeviceCharacteristics)(sqlite3_file*); 784 /* Methods above are valid for version 1 */ 785 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 786 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 787 void (*xShmBarrier)(sqlite3_file*); 788 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 789 /* Methods above are valid for version 2 */ 790 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 791 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 792 /* Methods above are valid for version 3 */ 793 /* Additional methods may be added in future releases */ 794}; 795 796/* 797** CAPI3REF: Standard File Control Opcodes 798** KEYWORDS: {file control opcodes} {file control opcode} 799** 800** These integer constants are opcodes for the xFileControl method 801** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 802** interface. 803** 804** <ul> 805** <li>[[SQLITE_FCNTL_LOCKSTATE]] 806** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 807** opcode causes the xFileControl method to write the current state of 808** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 809** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 810** into an integer that the pArg argument points to. This capability 811** is used during testing and is only available when the SQLITE_TEST 812** compile-time option is used. 813** 814** <li>[[SQLITE_FCNTL_SIZE_HINT]] 815** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 816** layer a hint of how large the database file will grow to be during the 817** current transaction. This hint is not guaranteed to be accurate but it 818** is often close. The underlying VFS might choose to preallocate database 819** file space based on this hint in order to help writes to the database 820** file run faster. 821** 822** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 823** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 824** extends and truncates the database file in chunks of a size specified 825** by the user. The fourth argument to [sqlite3_file_control()] should 826** point to an integer (type int) containing the new chunk-size to use 827** for the nominated database. Allocating database file space in large 828** chunks (say 1MB at a time), may reduce file-system fragmentation and 829** improve performance on some systems. 830** 831** <li>[[SQLITE_FCNTL_FILE_POINTER]] 832** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 833** to the [sqlite3_file] object associated with a particular database 834** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 835** 836** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 837** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 838** to the [sqlite3_file] object associated with the journal file (either 839** the [rollback journal] or the [write-ahead log]) for a particular database 840** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 841** 842** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 843** No longer in use. 844** 845** <li>[[SQLITE_FCNTL_SYNC]] 846** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 847** sent to the VFS immediately before the xSync method is invoked on a 848** database file descriptor. Or, if the xSync method is not invoked 849** because the user has configured SQLite with 850** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 851** of the xSync method. In most cases, the pointer argument passed with 852** this file-control is NULL. However, if the database file is being synced 853** as part of a multi-database commit, the argument points to a nul-terminated 854** string containing the transactions master-journal file name. VFSes that 855** do not need this signal should silently ignore this opcode. Applications 856** should not call [sqlite3_file_control()] with this opcode as doing so may 857** disrupt the operation of the specialized VFSes that do require it. 858** 859** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 860** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 861** and sent to the VFS after a transaction has been committed immediately 862** but before the database is unlocked. VFSes that do not need this signal 863** should silently ignore this opcode. Applications should not call 864** [sqlite3_file_control()] with this opcode as doing so may disrupt the 865** operation of the specialized VFSes that do require it. 866** 867** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 868** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 869** retry counts and intervals for certain disk I/O operations for the 870** windows [VFS] in order to provide robustness in the presence of 871** anti-virus programs. By default, the windows VFS will retry file read, 872** file write, and file delete operations up to 10 times, with a delay 873** of 25 milliseconds before the first retry and with the delay increasing 874** by an additional 25 milliseconds with each subsequent retry. This 875** opcode allows these two values (10 retries and 25 milliseconds of delay) 876** to be adjusted. The values are changed for all database connections 877** within the same process. The argument is a pointer to an array of two 878** integers where the first integer is the new retry count and the second 879** integer is the delay. If either integer is negative, then the setting 880** is not changed but instead the prior value of that setting is written 881** into the array entry, allowing the current retry settings to be 882** interrogated. The zDbName parameter is ignored. 883** 884** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 885** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 886** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 887** write ahead log and shared memory files used for transaction control 888** are automatically deleted when the latest connection to the database 889** closes. Setting persistent WAL mode causes those files to persist after 890** close. Persisting the files is useful when other processes that do not 891** have write permission on the directory containing the database file want 892** to read the database file, as the WAL and shared memory files must exist 893** in order for the database to be readable. The fourth parameter to 894** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 895** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 896** WAL mode. If the integer is -1, then it is overwritten with the current 897** WAL persistence setting. 898** 899** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 900** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 901** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 902** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 903** xDeviceCharacteristics methods. The fourth parameter to 904** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 905** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 906** mode. If the integer is -1, then it is overwritten with the current 907** zero-damage mode setting. 908** 909** <li>[[SQLITE_FCNTL_OVERWRITE]] 910** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 911** a write transaction to indicate that, unless it is rolled back for some 912** reason, the entire database file will be overwritten by the current 913** transaction. This is used by VACUUM operations. 914** 915** <li>[[SQLITE_FCNTL_VFSNAME]] 916** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 917** all [VFSes] in the VFS stack. The names are of all VFS shims and the 918** final bottom-level VFS are written into memory obtained from 919** [sqlite3_malloc()] and the result is stored in the char* variable 920** that the fourth parameter of [sqlite3_file_control()] points to. 921** The caller is responsible for freeing the memory when done. As with 922** all file-control actions, there is no guarantee that this will actually 923** do anything. Callers should initialize the char* variable to a NULL 924** pointer in case this file-control is not implemented. This file-control 925** is intended for diagnostic use only. 926** 927** <li>[[SQLITE_FCNTL_VFS_POINTER]] 928** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 929** [VFSes] currently in use. ^(The argument X in 930** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 931** of type "[sqlite3_vfs] **". This opcodes will set *X 932** to a pointer to the top-level VFS.)^ 933** ^When there are multiple VFS shims in the stack, this opcode finds the 934** upper-most shim only. 935** 936** <li>[[SQLITE_FCNTL_PRAGMA]] 937** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 938** file control is sent to the open [sqlite3_file] object corresponding 939** to the database file to which the pragma statement refers. ^The argument 940** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 941** pointers to strings (char**) in which the second element of the array 942** is the name of the pragma and the third element is the argument to the 943** pragma or NULL if the pragma has no argument. ^The handler for an 944** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 945** of the char** argument point to a string obtained from [sqlite3_mprintf()] 946** or the equivalent and that string will become the result of the pragma or 947** the error message if the pragma fails. ^If the 948** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 949** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 950** file control returns [SQLITE_OK], then the parser assumes that the 951** VFS has handled the PRAGMA itself and the parser generates a no-op 952** prepared statement if result string is NULL, or that returns a copy 953** of the result string if the string is non-NULL. 954** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 955** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 956** that the VFS encountered an error while handling the [PRAGMA] and the 957** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 958** file control occurs at the beginning of pragma statement analysis and so 959** it is able to override built-in [PRAGMA] statements. 960** 961** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 962** ^The [SQLITE_FCNTL_BUSYHANDLER] 963** file-control may be invoked by SQLite on the database file handle 964** shortly after it is opened in order to provide a custom VFS with access 965** to the connections busy-handler callback. The argument is of type (void **) 966** - an array of two (void *) values. The first (void *) actually points 967** to a function of type (int (*)(void *)). In order to invoke the connections 968** busy-handler, this function should be invoked with the second (void *) in 969** the array as the only argument. If it returns non-zero, then the operation 970** should be retried. If it returns zero, the custom VFS should abandon the 971** current operation. 972** 973** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 974** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 975** to have SQLite generate a 976** temporary filename using the same algorithm that is followed to generate 977** temporary filenames for TEMP tables and other internal uses. The 978** argument should be a char** which will be filled with the filename 979** written into memory obtained from [sqlite3_malloc()]. The caller should 980** invoke [sqlite3_free()] on the result to avoid a memory leak. 981** 982** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 983** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 984** maximum number of bytes that will be used for memory-mapped I/O. 985** The argument is a pointer to a value of type sqlite3_int64 that 986** is an advisory maximum number of bytes in the file to memory map. The 987** pointer is overwritten with the old value. The limit is not changed if 988** the value originally pointed to is negative, and so the current limit 989** can be queried by passing in a pointer to a negative number. This 990** file-control is used internally to implement [PRAGMA mmap_size]. 991** 992** <li>[[SQLITE_FCNTL_TRACE]] 993** The [SQLITE_FCNTL_TRACE] file control provides advisory information 994** to the VFS about what the higher layers of the SQLite stack are doing. 995** This file control is used by some VFS activity tracing [shims]. 996** The argument is a zero-terminated string. Higher layers in the 997** SQLite stack may generate instances of this file control if 998** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 999** 1000** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1001** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1002** pointer to an integer and it writes a boolean into that integer depending 1003** on whether or not the file has been renamed, moved, or deleted since it 1004** was first opened. 1005** 1006** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1007** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1008** underlying native file handle associated with a file handle. This file 1009** control interprets its argument as a pointer to a native file handle and 1010** writes the resulting value there. 1011** 1012** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1013** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1014** opcode causes the xFileControl method to swap the file handle with the one 1015** pointed to by the pArg argument. This capability is used during testing 1016** and only needs to be supported when SQLITE_TEST is defined. 1017** 1018** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1019** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1020** be advantageous to block on the next WAL lock if the lock is not immediately 1021** available. The WAL subsystem issues this signal during rare 1022** circumstances in order to fix a problem with priority inversion. 1023** Applications should <em>not</em> use this file-control. 1024** 1025** <li>[[SQLITE_FCNTL_ZIPVFS]] 1026** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1027** VFS should return SQLITE_NOTFOUND for this opcode. 1028** 1029** <li>[[SQLITE_FCNTL_RBU]] 1030** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1031** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1032** this opcode. 1033** 1034** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1035** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1036** the file descriptor is placed in "batch write mode", which 1037** means all subsequent write operations will be deferred and done 1038** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1039** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1040** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1041** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1042** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1043** no VFS interface calls on the same [sqlite3_file] file descriptor 1044** except for calls to the xWrite method and the xFileControl method 1045** with [SQLITE_FCNTL_SIZE_HINT]. 1046** 1047** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1048** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1049** operations since the previous successful call to 1050** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1051** This file control returns [SQLITE_OK] if and only if the writes were 1052** all performed successfully and have been committed to persistent storage. 1053** ^Regardless of whether or not it is successful, this file control takes 1054** the file descriptor out of batch write mode so that all subsequent 1055** write operations are independent. 1056** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1057** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1058** 1059** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1060** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1061** operations since the previous successful call to 1062** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1063** ^This file control takes the file descriptor out of batch write mode 1064** so that all subsequent write operations are independent. 1065** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1066** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1067** </ul> 1068*/ 1069#define SQLITE_FCNTL_LOCKSTATE 1 1070#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1071#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1072#define SQLITE_FCNTL_LAST_ERRNO 4 1073#define SQLITE_FCNTL_SIZE_HINT 5 1074#define SQLITE_FCNTL_CHUNK_SIZE 6 1075#define SQLITE_FCNTL_FILE_POINTER 7 1076#define SQLITE_FCNTL_SYNC_OMITTED 8 1077#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1078#define SQLITE_FCNTL_PERSIST_WAL 10 1079#define SQLITE_FCNTL_OVERWRITE 11 1080#define SQLITE_FCNTL_VFSNAME 12 1081#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1082#define SQLITE_FCNTL_PRAGMA 14 1083#define SQLITE_FCNTL_BUSYHANDLER 15 1084#define SQLITE_FCNTL_TEMPFILENAME 16 1085#define SQLITE_FCNTL_MMAP_SIZE 18 1086#define SQLITE_FCNTL_TRACE 19 1087#define SQLITE_FCNTL_HAS_MOVED 20 1088#define SQLITE_FCNTL_SYNC 21 1089#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1090#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1091#define SQLITE_FCNTL_WAL_BLOCK 24 1092#define SQLITE_FCNTL_ZIPVFS 25 1093#define SQLITE_FCNTL_RBU 26 1094#define SQLITE_FCNTL_VFS_POINTER 27 1095#define SQLITE_FCNTL_JOURNAL_POINTER 28 1096#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1097#define SQLITE_FCNTL_PDB 30 1098#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1099#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1100#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1101 1102/* deprecated names */ 1103#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1104#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1105#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1106 1107 1108/* 1109** CAPI3REF: Mutex Handle 1110** 1111** The mutex module within SQLite defines [sqlite3_mutex] to be an 1112** abstract type for a mutex object. The SQLite core never looks 1113** at the internal representation of an [sqlite3_mutex]. It only 1114** deals with pointers to the [sqlite3_mutex] object. 1115** 1116** Mutexes are created using [sqlite3_mutex_alloc()]. 1117*/ 1118typedef struct sqlite3_mutex sqlite3_mutex; 1119 1120/* 1121** CAPI3REF: Loadable Extension Thunk 1122** 1123** A pointer to the opaque sqlite3_api_routines structure is passed as 1124** the third parameter to entry points of [loadable extensions]. This 1125** structure must be typedefed in order to work around compiler warnings 1126** on some platforms. 1127*/ 1128typedef struct sqlite3_api_routines sqlite3_api_routines; 1129 1130/* 1131** CAPI3REF: OS Interface Object 1132** 1133** An instance of the sqlite3_vfs object defines the interface between 1134** the SQLite core and the underlying operating system. The "vfs" 1135** in the name of the object stands for "virtual file system". See 1136** the [VFS | VFS documentation] for further information. 1137** 1138** The VFS interface is sometimes extended by adding new methods onto 1139** the end. Each time such an extension occurs, the iVersion field 1140** is incremented. The iVersion value started out as 1 in 1141** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1142** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1143** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1144** may be appended to the sqlite3_vfs object and the iVersion value 1145** may increase again in future versions of SQLite. 1146** Note that the structure 1147** of the sqlite3_vfs object changes in the transition from 1148** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1149** and yet the iVersion field was not modified. 1150** 1151** The szOsFile field is the size of the subclassed [sqlite3_file] 1152** structure used by this VFS. mxPathname is the maximum length of 1153** a pathname in this VFS. 1154** 1155** Registered sqlite3_vfs objects are kept on a linked list formed by 1156** the pNext pointer. The [sqlite3_vfs_register()] 1157** and [sqlite3_vfs_unregister()] interfaces manage this list 1158** in a thread-safe way. The [sqlite3_vfs_find()] interface 1159** searches the list. Neither the application code nor the VFS 1160** implementation should use the pNext pointer. 1161** 1162** The pNext field is the only field in the sqlite3_vfs 1163** structure that SQLite will ever modify. SQLite will only access 1164** or modify this field while holding a particular static mutex. 1165** The application should never modify anything within the sqlite3_vfs 1166** object once the object has been registered. 1167** 1168** The zName field holds the name of the VFS module. The name must 1169** be unique across all VFS modules. 1170** 1171** [[sqlite3_vfs.xOpen]] 1172** ^SQLite guarantees that the zFilename parameter to xOpen 1173** is either a NULL pointer or string obtained 1174** from xFullPathname() with an optional suffix added. 1175** ^If a suffix is added to the zFilename parameter, it will 1176** consist of a single "-" character followed by no more than 1177** 11 alphanumeric and/or "-" characters. 1178** ^SQLite further guarantees that 1179** the string will be valid and unchanged until xClose() is 1180** called. Because of the previous sentence, 1181** the [sqlite3_file] can safely store a pointer to the 1182** filename if it needs to remember the filename for some reason. 1183** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1184** must invent its own temporary name for the file. ^Whenever the 1185** xFilename parameter is NULL it will also be the case that the 1186** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1187** 1188** The flags argument to xOpen() includes all bits set in 1189** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1190** or [sqlite3_open16()] is used, then flags includes at least 1191** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1192** If xOpen() opens a file read-only then it sets *pOutFlags to 1193** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1194** 1195** ^(SQLite will also add one of the following flags to the xOpen() 1196** call, depending on the object being opened: 1197** 1198** <ul> 1199** <li> [SQLITE_OPEN_MAIN_DB] 1200** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1201** <li> [SQLITE_OPEN_TEMP_DB] 1202** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1203** <li> [SQLITE_OPEN_TRANSIENT_DB] 1204** <li> [SQLITE_OPEN_SUBJOURNAL] 1205** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1206** <li> [SQLITE_OPEN_WAL] 1207** </ul>)^ 1208** 1209** The file I/O implementation can use the object type flags to 1210** change the way it deals with files. For example, an application 1211** that does not care about crash recovery or rollback might make 1212** the open of a journal file a no-op. Writes to this journal would 1213** also be no-ops, and any attempt to read the journal would return 1214** SQLITE_IOERR. Or the implementation might recognize that a database 1215** file will be doing page-aligned sector reads and writes in a random 1216** order and set up its I/O subsystem accordingly. 1217** 1218** SQLite might also add one of the following flags to the xOpen method: 1219** 1220** <ul> 1221** <li> [SQLITE_OPEN_DELETEONCLOSE] 1222** <li> [SQLITE_OPEN_EXCLUSIVE] 1223** </ul> 1224** 1225** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1226** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1227** will be set for TEMP databases and their journals, transient 1228** databases, and subjournals. 1229** 1230** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1231** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1232** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1233** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1234** SQLITE_OPEN_CREATE, is used to indicate that file should always 1235** be created, and that it is an error if it already exists. 1236** It is <i>not</i> used to indicate the file should be opened 1237** for exclusive access. 1238** 1239** ^At least szOsFile bytes of memory are allocated by SQLite 1240** to hold the [sqlite3_file] structure passed as the third 1241** argument to xOpen. The xOpen method does not have to 1242** allocate the structure; it should just fill it in. Note that 1243** the xOpen method must set the sqlite3_file.pMethods to either 1244** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1245** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1246** element will be valid after xOpen returns regardless of the success 1247** or failure of the xOpen call. 1248** 1249** [[sqlite3_vfs.xAccess]] 1250** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1251** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1252** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1253** to test whether a file is at least readable. The file can be a 1254** directory. 1255** 1256** ^SQLite will always allocate at least mxPathname+1 bytes for the 1257** output buffer xFullPathname. The exact size of the output buffer 1258** is also passed as a parameter to both methods. If the output buffer 1259** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1260** handled as a fatal error by SQLite, vfs implementations should endeavor 1261** to prevent this by setting mxPathname to a sufficiently large value. 1262** 1263** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1264** interfaces are not strictly a part of the filesystem, but they are 1265** included in the VFS structure for completeness. 1266** The xRandomness() function attempts to return nBytes bytes 1267** of good-quality randomness into zOut. The return value is 1268** the actual number of bytes of randomness obtained. 1269** The xSleep() method causes the calling thread to sleep for at 1270** least the number of microseconds given. ^The xCurrentTime() 1271** method returns a Julian Day Number for the current date and time as 1272** a floating point value. 1273** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1274** Day Number multiplied by 86400000 (the number of milliseconds in 1275** a 24-hour day). 1276** ^SQLite will use the xCurrentTimeInt64() method to get the current 1277** date and time if that method is available (if iVersion is 2 or 1278** greater and the function pointer is not NULL) and will fall back 1279** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1280** 1281** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1282** are not used by the SQLite core. These optional interfaces are provided 1283** by some VFSes to facilitate testing of the VFS code. By overriding 1284** system calls with functions under its control, a test program can 1285** simulate faults and error conditions that would otherwise be difficult 1286** or impossible to induce. The set of system calls that can be overridden 1287** varies from one VFS to another, and from one version of the same VFS to the 1288** next. Applications that use these interfaces must be prepared for any 1289** or all of these interfaces to be NULL or for their behavior to change 1290** from one release to the next. Applications must not attempt to access 1291** any of these methods if the iVersion of the VFS is less than 3. 1292*/ 1293typedef struct sqlite3_vfs sqlite3_vfs; 1294typedef void (*sqlite3_syscall_ptr)(void); 1295struct sqlite3_vfs { 1296 int iVersion; /* Structure version number (currently 3) */ 1297 int szOsFile; /* Size of subclassed sqlite3_file */ 1298 int mxPathname; /* Maximum file pathname length */ 1299 sqlite3_vfs *pNext; /* Next registered VFS */ 1300 const char *zName; /* Name of this virtual file system */ 1301 void *pAppData; /* Pointer to application-specific data */ 1302 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1303 int flags, int *pOutFlags); 1304 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1305 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1306 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1307 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1308 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1309 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1310 void (*xDlClose)(sqlite3_vfs*, void*); 1311 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1312 int (*xSleep)(sqlite3_vfs*, int microseconds); 1313 int (*xCurrentTime)(sqlite3_vfs*, double*); 1314 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1315 /* 1316 ** The methods above are in version 1 of the sqlite_vfs object 1317 ** definition. Those that follow are added in version 2 or later 1318 */ 1319 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1320 /* 1321 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1322 ** Those below are for version 3 and greater. 1323 */ 1324 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1325 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1326 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1327 /* 1328 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1329 ** New fields may be appended in future versions. The iVersion 1330 ** value will increment whenever this happens. 1331 */ 1332}; 1333 1334/* 1335** CAPI3REF: Flags for the xAccess VFS method 1336** 1337** These integer constants can be used as the third parameter to 1338** the xAccess method of an [sqlite3_vfs] object. They determine 1339** what kind of permissions the xAccess method is looking for. 1340** With SQLITE_ACCESS_EXISTS, the xAccess method 1341** simply checks whether the file exists. 1342** With SQLITE_ACCESS_READWRITE, the xAccess method 1343** checks whether the named directory is both readable and writable 1344** (in other words, if files can be added, removed, and renamed within 1345** the directory). 1346** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1347** [temp_store_directory pragma], though this could change in a future 1348** release of SQLite. 1349** With SQLITE_ACCESS_READ, the xAccess method 1350** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1351** currently unused, though it might be used in a future release of 1352** SQLite. 1353*/ 1354#define SQLITE_ACCESS_EXISTS 0 1355#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1356#define SQLITE_ACCESS_READ 2 /* Unused */ 1357 1358/* 1359** CAPI3REF: Flags for the xShmLock VFS method 1360** 1361** These integer constants define the various locking operations 1362** allowed by the xShmLock method of [sqlite3_io_methods]. The 1363** following are the only legal combinations of flags to the 1364** xShmLock method: 1365** 1366** <ul> 1367** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1368** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1369** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1370** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1371** </ul> 1372** 1373** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1374** was given on the corresponding lock. 1375** 1376** The xShmLock method can transition between unlocked and SHARED or 1377** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1378** and EXCLUSIVE. 1379*/ 1380#define SQLITE_SHM_UNLOCK 1 1381#define SQLITE_SHM_LOCK 2 1382#define SQLITE_SHM_SHARED 4 1383#define SQLITE_SHM_EXCLUSIVE 8 1384 1385/* 1386** CAPI3REF: Maximum xShmLock index 1387** 1388** The xShmLock method on [sqlite3_io_methods] may use values 1389** between 0 and this upper bound as its "offset" argument. 1390** The SQLite core will never attempt to acquire or release a 1391** lock outside of this range 1392*/ 1393#define SQLITE_SHM_NLOCK 8 1394 1395 1396/* 1397** CAPI3REF: Initialize The SQLite Library 1398** 1399** ^The sqlite3_initialize() routine initializes the 1400** SQLite library. ^The sqlite3_shutdown() routine 1401** deallocates any resources that were allocated by sqlite3_initialize(). 1402** These routines are designed to aid in process initialization and 1403** shutdown on embedded systems. Workstation applications using 1404** SQLite normally do not need to invoke either of these routines. 1405** 1406** A call to sqlite3_initialize() is an "effective" call if it is 1407** the first time sqlite3_initialize() is invoked during the lifetime of 1408** the process, or if it is the first time sqlite3_initialize() is invoked 1409** following a call to sqlite3_shutdown(). ^(Only an effective call 1410** of sqlite3_initialize() does any initialization. All other calls 1411** are harmless no-ops.)^ 1412** 1413** A call to sqlite3_shutdown() is an "effective" call if it is the first 1414** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1415** an effective call to sqlite3_shutdown() does any deinitialization. 1416** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1417** 1418** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1419** is not. The sqlite3_shutdown() interface must only be called from a 1420** single thread. All open [database connections] must be closed and all 1421** other SQLite resources must be deallocated prior to invoking 1422** sqlite3_shutdown(). 1423** 1424** Among other things, ^sqlite3_initialize() will invoke 1425** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1426** will invoke sqlite3_os_end(). 1427** 1428** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1429** ^If for some reason, sqlite3_initialize() is unable to initialize 1430** the library (perhaps it is unable to allocate a needed resource such 1431** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1432** 1433** ^The sqlite3_initialize() routine is called internally by many other 1434** SQLite interfaces so that an application usually does not need to 1435** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1436** calls sqlite3_initialize() so the SQLite library will be automatically 1437** initialized when [sqlite3_open()] is called if it has not be initialized 1438** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1439** compile-time option, then the automatic calls to sqlite3_initialize() 1440** are omitted and the application must call sqlite3_initialize() directly 1441** prior to using any other SQLite interface. For maximum portability, 1442** it is recommended that applications always invoke sqlite3_initialize() 1443** directly prior to using any other SQLite interface. Future releases 1444** of SQLite may require this. In other words, the behavior exhibited 1445** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1446** default behavior in some future release of SQLite. 1447** 1448** The sqlite3_os_init() routine does operating-system specific 1449** initialization of the SQLite library. The sqlite3_os_end() 1450** routine undoes the effect of sqlite3_os_init(). Typical tasks 1451** performed by these routines include allocation or deallocation 1452** of static resources, initialization of global variables, 1453** setting up a default [sqlite3_vfs] module, or setting up 1454** a default configuration using [sqlite3_config()]. 1455** 1456** The application should never invoke either sqlite3_os_init() 1457** or sqlite3_os_end() directly. The application should only invoke 1458** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1459** interface is called automatically by sqlite3_initialize() and 1460** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1461** implementations for sqlite3_os_init() and sqlite3_os_end() 1462** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1463** When [custom builds | built for other platforms] 1464** (using the [SQLITE_OS_OTHER=1] compile-time 1465** option) the application must supply a suitable implementation for 1466** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1467** implementation of sqlite3_os_init() or sqlite3_os_end() 1468** must return [SQLITE_OK] on success and some other [error code] upon 1469** failure. 1470*/ 1471int sqlite3_initialize(void); 1472int sqlite3_shutdown(void); 1473int sqlite3_os_init(void); 1474int sqlite3_os_end(void); 1475 1476/* 1477** CAPI3REF: Configuring The SQLite Library 1478** 1479** The sqlite3_config() interface is used to make global configuration 1480** changes to SQLite in order to tune SQLite to the specific needs of 1481** the application. The default configuration is recommended for most 1482** applications and so this routine is usually not necessary. It is 1483** provided to support rare applications with unusual needs. 1484** 1485** <b>The sqlite3_config() interface is not threadsafe. The application 1486** must ensure that no other SQLite interfaces are invoked by other 1487** threads while sqlite3_config() is running.</b> 1488** 1489** The sqlite3_config() interface 1490** may only be invoked prior to library initialization using 1491** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1492** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1493** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1494** Note, however, that ^sqlite3_config() can be called as part of the 1495** implementation of an application-defined [sqlite3_os_init()]. 1496** 1497** The first argument to sqlite3_config() is an integer 1498** [configuration option] that determines 1499** what property of SQLite is to be configured. Subsequent arguments 1500** vary depending on the [configuration option] 1501** in the first argument. 1502** 1503** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1504** ^If the option is unknown or SQLite is unable to set the option 1505** then this routine returns a non-zero [error code]. 1506*/ 1507int sqlite3_config(int, ...); 1508 1509/* 1510** CAPI3REF: Configure database connections 1511** METHOD: sqlite3 1512** 1513** The sqlite3_db_config() interface is used to make configuration 1514** changes to a [database connection]. The interface is similar to 1515** [sqlite3_config()] except that the changes apply to a single 1516** [database connection] (specified in the first argument). 1517** 1518** The second argument to sqlite3_db_config(D,V,...) is the 1519** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1520** that indicates what aspect of the [database connection] is being configured. 1521** Subsequent arguments vary depending on the configuration verb. 1522** 1523** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1524** the call is considered successful. 1525*/ 1526int sqlite3_db_config(sqlite3*, int op, ...); 1527 1528/* 1529** CAPI3REF: Memory Allocation Routines 1530** 1531** An instance of this object defines the interface between SQLite 1532** and low-level memory allocation routines. 1533** 1534** This object is used in only one place in the SQLite interface. 1535** A pointer to an instance of this object is the argument to 1536** [sqlite3_config()] when the configuration option is 1537** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1538** By creating an instance of this object 1539** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1540** during configuration, an application can specify an alternative 1541** memory allocation subsystem for SQLite to use for all of its 1542** dynamic memory needs. 1543** 1544** Note that SQLite comes with several [built-in memory allocators] 1545** that are perfectly adequate for the overwhelming majority of applications 1546** and that this object is only useful to a tiny minority of applications 1547** with specialized memory allocation requirements. This object is 1548** also used during testing of SQLite in order to specify an alternative 1549** memory allocator that simulates memory out-of-memory conditions in 1550** order to verify that SQLite recovers gracefully from such 1551** conditions. 1552** 1553** The xMalloc, xRealloc, and xFree methods must work like the 1554** malloc(), realloc() and free() functions from the standard C library. 1555** ^SQLite guarantees that the second argument to 1556** xRealloc is always a value returned by a prior call to xRoundup. 1557** 1558** xSize should return the allocated size of a memory allocation 1559** previously obtained from xMalloc or xRealloc. The allocated size 1560** is always at least as big as the requested size but may be larger. 1561** 1562** The xRoundup method returns what would be the allocated size of 1563** a memory allocation given a particular requested size. Most memory 1564** allocators round up memory allocations at least to the next multiple 1565** of 8. Some allocators round up to a larger multiple or to a power of 2. 1566** Every memory allocation request coming in through [sqlite3_malloc()] 1567** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1568** that causes the corresponding memory allocation to fail. 1569** 1570** The xInit method initializes the memory allocator. For example, 1571** it might allocate any require mutexes or initialize internal data 1572** structures. The xShutdown method is invoked (indirectly) by 1573** [sqlite3_shutdown()] and should deallocate any resources acquired 1574** by xInit. The pAppData pointer is used as the only parameter to 1575** xInit and xShutdown. 1576** 1577** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1578** the xInit method, so the xInit method need not be threadsafe. The 1579** xShutdown method is only called from [sqlite3_shutdown()] so it does 1580** not need to be threadsafe either. For all other methods, SQLite 1581** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1582** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1583** it is by default) and so the methods are automatically serialized. 1584** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1585** methods must be threadsafe or else make their own arrangements for 1586** serialization. 1587** 1588** SQLite will never invoke xInit() more than once without an intervening 1589** call to xShutdown(). 1590*/ 1591typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1592struct sqlite3_mem_methods { 1593 void *(*xMalloc)(int); /* Memory allocation function */ 1594 void (*xFree)(void*); /* Free a prior allocation */ 1595 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1596 int (*xSize)(void*); /* Return the size of an allocation */ 1597 int (*xRoundup)(int); /* Round up request size to allocation size */ 1598 int (*xInit)(void*); /* Initialize the memory allocator */ 1599 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1600 void *pAppData; /* Argument to xInit() and xShutdown() */ 1601}; 1602 1603/* 1604** CAPI3REF: Configuration Options 1605** KEYWORDS: {configuration option} 1606** 1607** These constants are the available integer configuration options that 1608** can be passed as the first argument to the [sqlite3_config()] interface. 1609** 1610** New configuration options may be added in future releases of SQLite. 1611** Existing configuration options might be discontinued. Applications 1612** should check the return code from [sqlite3_config()] to make sure that 1613** the call worked. The [sqlite3_config()] interface will return a 1614** non-zero [error code] if a discontinued or unsupported configuration option 1615** is invoked. 1616** 1617** <dl> 1618** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1619** <dd>There are no arguments to this option. ^This option sets the 1620** [threading mode] to Single-thread. In other words, it disables 1621** all mutexing and puts SQLite into a mode where it can only be used 1622** by a single thread. ^If SQLite is compiled with 1623** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1624** it is not possible to change the [threading mode] from its default 1625** value of Single-thread and so [sqlite3_config()] will return 1626** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1627** configuration option.</dd> 1628** 1629** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1630** <dd>There are no arguments to this option. ^This option sets the 1631** [threading mode] to Multi-thread. In other words, it disables 1632** mutexing on [database connection] and [prepared statement] objects. 1633** The application is responsible for serializing access to 1634** [database connections] and [prepared statements]. But other mutexes 1635** are enabled so that SQLite will be safe to use in a multi-threaded 1636** environment as long as no two threads attempt to use the same 1637** [database connection] at the same time. ^If SQLite is compiled with 1638** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1639** it is not possible to set the Multi-thread [threading mode] and 1640** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1641** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1642** 1643** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1644** <dd>There are no arguments to this option. ^This option sets the 1645** [threading mode] to Serialized. In other words, this option enables 1646** all mutexes including the recursive 1647** mutexes on [database connection] and [prepared statement] objects. 1648** In this mode (which is the default when SQLite is compiled with 1649** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1650** to [database connections] and [prepared statements] so that the 1651** application is free to use the same [database connection] or the 1652** same [prepared statement] in different threads at the same time. 1653** ^If SQLite is compiled with 1654** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1655** it is not possible to set the Serialized [threading mode] and 1656** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1657** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1658** 1659** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1660** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1661** a pointer to an instance of the [sqlite3_mem_methods] structure. 1662** The argument specifies 1663** alternative low-level memory allocation routines to be used in place of 1664** the memory allocation routines built into SQLite.)^ ^SQLite makes 1665** its own private copy of the content of the [sqlite3_mem_methods] structure 1666** before the [sqlite3_config()] call returns.</dd> 1667** 1668** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1669** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1670** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1671** The [sqlite3_mem_methods] 1672** structure is filled with the currently defined memory allocation routines.)^ 1673** This option can be used to overload the default memory allocation 1674** routines with a wrapper that simulations memory allocation failure or 1675** tracks memory usage, for example. </dd> 1676** 1677** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1678** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1679** type int, interpreted as a boolean, which if true provides a hint to 1680** SQLite that it should avoid large memory allocations if possible. 1681** SQLite will run faster if it is free to make large memory allocations, 1682** but some application might prefer to run slower in exchange for 1683** guarantees about memory fragmentation that are possible if large 1684** allocations are avoided. This hint is normally off. 1685** </dd> 1686** 1687** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1688** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1689** interpreted as a boolean, which enables or disables the collection of 1690** memory allocation statistics. ^(When memory allocation statistics are 1691** disabled, the following SQLite interfaces become non-operational: 1692** <ul> 1693** <li> [sqlite3_memory_used()] 1694** <li> [sqlite3_memory_highwater()] 1695** <li> [sqlite3_soft_heap_limit64()] 1696** <li> [sqlite3_status64()] 1697** </ul>)^ 1698** ^Memory allocation statistics are enabled by default unless SQLite is 1699** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1700** allocation statistics are disabled by default. 1701** </dd> 1702** 1703** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1704** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1705** </dd> 1706** 1707** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1708** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1709** that SQLite can use for the database page cache with the default page 1710** cache implementation. 1711** This configuration option is a no-op if an application-define page 1712** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1713** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1714** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1715** and the number of cache lines (N). 1716** The sz argument should be the size of the largest database page 1717** (a power of two between 512 and 65536) plus some extra bytes for each 1718** page header. ^The number of extra bytes needed by the page header 1719** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1720** ^It is harmless, apart from the wasted memory, 1721** for the sz parameter to be larger than necessary. The pMem 1722** argument must be either a NULL pointer or a pointer to an 8-byte 1723** aligned block of memory of at least sz*N bytes, otherwise 1724** subsequent behavior is undefined. 1725** ^When pMem is not NULL, SQLite will strive to use the memory provided 1726** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1727** a page cache line is larger than sz bytes or if all of the pMem buffer 1728** is exhausted. 1729** ^If pMem is NULL and N is non-zero, then each database connection 1730** does an initial bulk allocation for page cache memory 1731** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1732** of -1024*N bytes if N is negative, . ^If additional 1733** page cache memory is needed beyond what is provided by the initial 1734** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1735** additional cache line. </dd> 1736** 1737** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1738** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1739** that SQLite will use for all of its dynamic memory allocation needs 1740** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1741** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1742** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1743** [SQLITE_ERROR] if invoked otherwise. 1744** ^There are three arguments to SQLITE_CONFIG_HEAP: 1745** An 8-byte aligned pointer to the memory, 1746** the number of bytes in the memory buffer, and the minimum allocation size. 1747** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1748** to using its default memory allocator (the system malloc() implementation), 1749** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1750** memory pointer is not NULL then the alternative memory 1751** allocator is engaged to handle all of SQLites memory allocation needs. 1752** The first pointer (the memory pointer) must be aligned to an 8-byte 1753** boundary or subsequent behavior of SQLite will be undefined. 1754** The minimum allocation size is capped at 2**12. Reasonable values 1755** for the minimum allocation size are 2**5 through 2**8.</dd> 1756** 1757** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1758** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1759** pointer to an instance of the [sqlite3_mutex_methods] structure. 1760** The argument specifies alternative low-level mutex routines to be used 1761** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1762** the content of the [sqlite3_mutex_methods] structure before the call to 1763** [sqlite3_config()] returns. ^If SQLite is compiled with 1764** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1765** the entire mutexing subsystem is omitted from the build and hence calls to 1766** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1767** return [SQLITE_ERROR].</dd> 1768** 1769** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1770** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1771** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1772** [sqlite3_mutex_methods] 1773** structure is filled with the currently defined mutex routines.)^ 1774** This option can be used to overload the default mutex allocation 1775** routines with a wrapper used to track mutex usage for performance 1776** profiling or testing, for example. ^If SQLite is compiled with 1777** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1778** the entire mutexing subsystem is omitted from the build and hence calls to 1779** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1780** return [SQLITE_ERROR].</dd> 1781** 1782** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1783** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1784** the default size of lookaside memory on each [database connection]. 1785** The first argument is the 1786** size of each lookaside buffer slot and the second is the number of 1787** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1788** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1789** option to [sqlite3_db_config()] can be used to change the lookaside 1790** configuration on individual connections.)^ </dd> 1791** 1792** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1793** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1794** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1795** the interface to a custom page cache implementation.)^ 1796** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1797** 1798** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1799** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1800** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1801** the current page cache implementation into that object.)^ </dd> 1802** 1803** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1804** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1805** global [error log]. 1806** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1807** function with a call signature of void(*)(void*,int,const char*), 1808** and a pointer to void. ^If the function pointer is not NULL, it is 1809** invoked by [sqlite3_log()] to process each logging event. ^If the 1810** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1811** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1812** passed through as the first parameter to the application-defined logger 1813** function whenever that function is invoked. ^The second parameter to 1814** the logger function is a copy of the first parameter to the corresponding 1815** [sqlite3_log()] call and is intended to be a [result code] or an 1816** [extended result code]. ^The third parameter passed to the logger is 1817** log message after formatting via [sqlite3_snprintf()]. 1818** The SQLite logging interface is not reentrant; the logger function 1819** supplied by the application must not invoke any SQLite interface. 1820** In a multi-threaded application, the application-defined logger 1821** function must be threadsafe. </dd> 1822** 1823** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1824** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1825** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1826** then URI handling is globally disabled.)^ ^If URI handling is globally 1827** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1828** [sqlite3_open16()] or 1829** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1830** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1831** connection is opened. ^If it is globally disabled, filenames are 1832** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1833** database connection is opened. ^(By default, URI handling is globally 1834** disabled. The default value may be changed by compiling with the 1835** [SQLITE_USE_URI] symbol defined.)^ 1836** 1837** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1838** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1839** argument which is interpreted as a boolean in order to enable or disable 1840** the use of covering indices for full table scans in the query optimizer. 1841** ^The default setting is determined 1842** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1843** if that compile-time option is omitted. 1844** The ability to disable the use of covering indices for full table scans 1845** is because some incorrectly coded legacy applications might malfunction 1846** when the optimization is enabled. Providing the ability to 1847** disable the optimization allows the older, buggy application code to work 1848** without change even with newer versions of SQLite. 1849** 1850** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1851** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1852** <dd> These options are obsolete and should not be used by new code. 1853** They are retained for backwards compatibility but are now no-ops. 1854** </dd> 1855** 1856** [[SQLITE_CONFIG_SQLLOG]] 1857** <dt>SQLITE_CONFIG_SQLLOG 1858** <dd>This option is only available if sqlite is compiled with the 1859** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1860** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1861** The second should be of type (void*). The callback is invoked by the library 1862** in three separate circumstances, identified by the value passed as the 1863** fourth parameter. If the fourth parameter is 0, then the database connection 1864** passed as the second argument has just been opened. The third argument 1865** points to a buffer containing the name of the main database file. If the 1866** fourth parameter is 1, then the SQL statement that the third parameter 1867** points to has just been executed. Or, if the fourth parameter is 2, then 1868** the connection being passed as the second parameter is being closed. The 1869** third parameter is passed NULL In this case. An example of using this 1870** configuration option can be seen in the "test_sqllog.c" source file in 1871** the canonical SQLite source tree.</dd> 1872** 1873** [[SQLITE_CONFIG_MMAP_SIZE]] 1874** <dt>SQLITE_CONFIG_MMAP_SIZE 1875** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1876** that are the default mmap size limit (the default setting for 1877** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1878** ^The default setting can be overridden by each database connection using 1879** either the [PRAGMA mmap_size] command, or by using the 1880** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1881** will be silently truncated if necessary so that it does not exceed the 1882** compile-time maximum mmap size set by the 1883** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1884** ^If either argument to this option is negative, then that argument is 1885** changed to its compile-time default. 1886** 1887** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1888** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1889** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1890** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1891** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1892** that specifies the maximum size of the created heap. 1893** 1894** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1895** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1896** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1897** is a pointer to an integer and writes into that integer the number of extra 1898** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1899** The amount of extra space required can change depending on the compiler, 1900** target platform, and SQLite version. 1901** 1902** [[SQLITE_CONFIG_PMASZ]] 1903** <dt>SQLITE_CONFIG_PMASZ 1904** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1905** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1906** sorter to that integer. The default minimum PMA Size is set by the 1907** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1908** to help with sort operations when multithreaded sorting 1909** is enabled (using the [PRAGMA threads] command) and the amount of content 1910** to be sorted exceeds the page size times the minimum of the 1911** [PRAGMA cache_size] setting and this value. 1912** 1913** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1914** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1915** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1916** becomes the [statement journal] spill-to-disk threshold. 1917** [Statement journals] are held in memory until their size (in bytes) 1918** exceeds this threshold, at which point they are written to disk. 1919** Or if the threshold is -1, statement journals are always held 1920** exclusively in memory. 1921** Since many statement journals never become large, setting the spill 1922** threshold to a value such as 64KiB can greatly reduce the amount of 1923** I/O required to support statement rollback. 1924** The default value for this setting is controlled by the 1925** [SQLITE_STMTJRNL_SPILL] compile-time option. 1926** </dl> 1927*/ 1928#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1929#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1930#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1931#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1932#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1933#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1934#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1935#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1936#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1937#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1938#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1939/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1940#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1941#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1942#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1943#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1944#define SQLITE_CONFIG_URI 17 /* int */ 1945#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1946#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1947#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1948#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1949#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1950#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1951#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1952#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1953#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1954#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1955 1956/* 1957** CAPI3REF: Database Connection Configuration Options 1958** 1959** These constants are the available integer configuration options that 1960** can be passed as the second argument to the [sqlite3_db_config()] interface. 1961** 1962** New configuration options may be added in future releases of SQLite. 1963** Existing configuration options might be discontinued. Applications 1964** should check the return code from [sqlite3_db_config()] to make sure that 1965** the call worked. ^The [sqlite3_db_config()] interface will return a 1966** non-zero [error code] if a discontinued or unsupported configuration option 1967** is invoked. 1968** 1969** <dl> 1970** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1971** <dd> ^This option takes three additional arguments that determine the 1972** [lookaside memory allocator] configuration for the [database connection]. 1973** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1974** pointer to a memory buffer to use for lookaside memory. 1975** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1976** may be NULL in which case SQLite will allocate the 1977** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1978** size of each lookaside buffer slot. ^The third argument is the number of 1979** slots. The size of the buffer in the first argument must be greater than 1980** or equal to the product of the second and third arguments. The buffer 1981** must be aligned to an 8-byte boundary. ^If the second argument to 1982** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1983** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1984** configuration for a database connection can only be changed when that 1985** connection is not currently using lookaside memory, or in other words 1986** when the "current value" returned by 1987** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1988** Any attempt to change the lookaside memory configuration when lookaside 1989** memory is in use leaves the configuration unchanged and returns 1990** [SQLITE_BUSY].)^</dd> 1991** 1992** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1993** <dd> ^This option is used to enable or disable the enforcement of 1994** [foreign key constraints]. There should be two additional arguments. 1995** The first argument is an integer which is 0 to disable FK enforcement, 1996** positive to enable FK enforcement or negative to leave FK enforcement 1997** unchanged. The second parameter is a pointer to an integer into which 1998** is written 0 or 1 to indicate whether FK enforcement is off or on 1999** following this call. The second parameter may be a NULL pointer, in 2000** which case the FK enforcement setting is not reported back. </dd> 2001** 2002** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2003** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2004** There should be two additional arguments. 2005** The first argument is an integer which is 0 to disable triggers, 2006** positive to enable triggers or negative to leave the setting unchanged. 2007** The second parameter is a pointer to an integer into which 2008** is written 0 or 1 to indicate whether triggers are disabled or enabled 2009** following this call. The second parameter may be a NULL pointer, in 2010** which case the trigger setting is not reported back. </dd> 2011** 2012** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2013** <dd> ^This option is used to enable or disable the two-argument 2014** version of the [fts3_tokenizer()] function which is part of the 2015** [FTS3] full-text search engine extension. 2016** There should be two additional arguments. 2017** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2018** positive to enable fts3_tokenizer() or negative to leave the setting 2019** unchanged. 2020** The second parameter is a pointer to an integer into which 2021** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2022** following this call. The second parameter may be a NULL pointer, in 2023** which case the new setting is not reported back. </dd> 2024** 2025** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2026** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2027** interface independently of the [load_extension()] SQL function. 2028** The [sqlite3_enable_load_extension()] API enables or disables both the 2029** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2030** There should be two additional arguments. 2031** When the first argument to this interface is 1, then only the C-API is 2032** enabled and the SQL function remains disabled. If the first argument to 2033** this interface is 0, then both the C-API and the SQL function are disabled. 2034** If the first argument is -1, then no changes are made to state of either the 2035** C-API or the SQL function. 2036** The second parameter is a pointer to an integer into which 2037** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2038** is disabled or enabled following this call. The second parameter may 2039** be a NULL pointer, in which case the new setting is not reported back. 2040** </dd> 2041** 2042** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2043** <dd> ^This option is used to change the name of the "main" database 2044** schema. ^The sole argument is a pointer to a constant UTF8 string 2045** which will become the new schema name in place of "main". ^SQLite 2046** does not make a copy of the new main schema name string, so the application 2047** must ensure that the argument passed into this DBCONFIG option is unchanged 2048** until after the database connection closes. 2049** </dd> 2050** 2051** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2052** <dd> Usually, when a database in wal mode is closed or detached from a 2053** database handle, SQLite checks if this will mean that there are now no 2054** connections at all to the database. If so, it performs a checkpoint 2055** operation before closing the connection. This option may be used to 2056** override this behaviour. The first parameter passed to this operation 2057** is an integer - non-zero to disable checkpoints-on-close, or zero (the 2058** default) to enable them. The second parameter is a pointer to an integer 2059** into which is written 0 or 1 to indicate whether checkpoints-on-close 2060** have been disabled - 0 if they are not disabled, 1 if they are. 2061** </dd> 2062** 2063** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2064** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2065** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2066** a single SQL query statement will always use the same algorithm regardless 2067** of values of [bound parameters].)^ The QPSG disables some query optimizations 2068** that look at the values of bound parameters, which can make some queries 2069** slower. But the QPSG has the advantage of more predictable behavior. With 2070** the QPSG active, SQLite will always use the same query plan in the field as 2071** was used during testing in the lab. 2072** </dd> 2073** 2074** </dl> 2075*/ 2076#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2077#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2078#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2079#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2080#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2081#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2082#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2083#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2084 2085 2086/* 2087** CAPI3REF: Enable Or Disable Extended Result Codes 2088** METHOD: sqlite3 2089** 2090** ^The sqlite3_extended_result_codes() routine enables or disables the 2091** [extended result codes] feature of SQLite. ^The extended result 2092** codes are disabled by default for historical compatibility. 2093*/ 2094int sqlite3_extended_result_codes(sqlite3*, int onoff); 2095 2096/* 2097** CAPI3REF: Last Insert Rowid 2098** METHOD: sqlite3 2099** 2100** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2101** has a unique 64-bit signed 2102** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2103** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2104** names are not also used by explicitly declared columns. ^If 2105** the table has a column of type [INTEGER PRIMARY KEY] then that column 2106** is another alias for the rowid. 2107** 2108** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2109** the most recent successful [INSERT] into a rowid table or [virtual table] 2110** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2111** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2112** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2113** zero. 2114** 2115** As well as being set automatically as rows are inserted into database 2116** tables, the value returned by this function may be set explicitly by 2117** [sqlite3_set_last_insert_rowid()] 2118** 2119** Some virtual table implementations may INSERT rows into rowid tables as 2120** part of committing a transaction (e.g. to flush data accumulated in memory 2121** to disk). In this case subsequent calls to this function return the rowid 2122** associated with these internal INSERT operations, which leads to 2123** unintuitive results. Virtual table implementations that do write to rowid 2124** tables in this way can avoid this problem by restoring the original 2125** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2126** control to the user. 2127** 2128** ^(If an [INSERT] occurs within a trigger then this routine will 2129** return the [rowid] of the inserted row as long as the trigger is 2130** running. Once the trigger program ends, the value returned 2131** by this routine reverts to what it was before the trigger was fired.)^ 2132** 2133** ^An [INSERT] that fails due to a constraint violation is not a 2134** successful [INSERT] and does not change the value returned by this 2135** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2136** and INSERT OR ABORT make no changes to the return value of this 2137** routine when their insertion fails. ^(When INSERT OR REPLACE 2138** encounters a constraint violation, it does not fail. The 2139** INSERT continues to completion after deleting rows that caused 2140** the constraint problem so INSERT OR REPLACE will always change 2141** the return value of this interface.)^ 2142** 2143** ^For the purposes of this routine, an [INSERT] is considered to 2144** be successful even if it is subsequently rolled back. 2145** 2146** This function is accessible to SQL statements via the 2147** [last_insert_rowid() SQL function]. 2148** 2149** If a separate thread performs a new [INSERT] on the same 2150** database connection while the [sqlite3_last_insert_rowid()] 2151** function is running and thus changes the last insert [rowid], 2152** then the value returned by [sqlite3_last_insert_rowid()] is 2153** unpredictable and might not equal either the old or the new 2154** last insert [rowid]. 2155*/ 2156sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2157 2158/* 2159** CAPI3REF: Set the Last Insert Rowid value. 2160** METHOD: sqlite3 2161** 2162** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2163** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2164** without inserting a row into the database. 2165*/ 2166void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2167 2168/* 2169** CAPI3REF: Count The Number Of Rows Modified 2170** METHOD: sqlite3 2171** 2172** ^This function returns the number of rows modified, inserted or 2173** deleted by the most recently completed INSERT, UPDATE or DELETE 2174** statement on the database connection specified by the only parameter. 2175** ^Executing any other type of SQL statement does not modify the value 2176** returned by this function. 2177** 2178** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2179** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2180** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2181** 2182** Changes to a view that are intercepted by 2183** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2184** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2185** DELETE statement run on a view is always zero. Only changes made to real 2186** tables are counted. 2187** 2188** Things are more complicated if the sqlite3_changes() function is 2189** executed while a trigger program is running. This may happen if the 2190** program uses the [changes() SQL function], or if some other callback 2191** function invokes sqlite3_changes() directly. Essentially: 2192** 2193** <ul> 2194** <li> ^(Before entering a trigger program the value returned by 2195** sqlite3_changes() function is saved. After the trigger program 2196** has finished, the original value is restored.)^ 2197** 2198** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2199** statement sets the value returned by sqlite3_changes() 2200** upon completion as normal. Of course, this value will not include 2201** any changes performed by sub-triggers, as the sqlite3_changes() 2202** value will be saved and restored after each sub-trigger has run.)^ 2203** </ul> 2204** 2205** ^This means that if the changes() SQL function (or similar) is used 2206** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2207** returns the value as set when the calling statement began executing. 2208** ^If it is used by the second or subsequent such statement within a trigger 2209** program, the value returned reflects the number of rows modified by the 2210** previous INSERT, UPDATE or DELETE statement within the same trigger. 2211** 2212** See also the [sqlite3_total_changes()] interface, the 2213** [count_changes pragma], and the [changes() SQL function]. 2214** 2215** If a separate thread makes changes on the same database connection 2216** while [sqlite3_changes()] is running then the value returned 2217** is unpredictable and not meaningful. 2218*/ 2219int sqlite3_changes(sqlite3*); 2220 2221/* 2222** CAPI3REF: Total Number Of Rows Modified 2223** METHOD: sqlite3 2224** 2225** ^This function returns the total number of rows inserted, modified or 2226** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2227** since the database connection was opened, including those executed as 2228** part of trigger programs. ^Executing any other type of SQL statement 2229** does not affect the value returned by sqlite3_total_changes(). 2230** 2231** ^Changes made as part of [foreign key actions] are included in the 2232** count, but those made as part of REPLACE constraint resolution are 2233** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2234** are not counted. 2235** 2236** See also the [sqlite3_changes()] interface, the 2237** [count_changes pragma], and the [total_changes() SQL function]. 2238** 2239** If a separate thread makes changes on the same database connection 2240** while [sqlite3_total_changes()] is running then the value 2241** returned is unpredictable and not meaningful. 2242*/ 2243int sqlite3_total_changes(sqlite3*); 2244 2245/* 2246** CAPI3REF: Interrupt A Long-Running Query 2247** METHOD: sqlite3 2248** 2249** ^This function causes any pending database operation to abort and 2250** return at its earliest opportunity. This routine is typically 2251** called in response to a user action such as pressing "Cancel" 2252** or Ctrl-C where the user wants a long query operation to halt 2253** immediately. 2254** 2255** ^It is safe to call this routine from a thread different from the 2256** thread that is currently running the database operation. But it 2257** is not safe to call this routine with a [database connection] that 2258** is closed or might close before sqlite3_interrupt() returns. 2259** 2260** ^If an SQL operation is very nearly finished at the time when 2261** sqlite3_interrupt() is called, then it might not have an opportunity 2262** to be interrupted and might continue to completion. 2263** 2264** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2265** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2266** that is inside an explicit transaction, then the entire transaction 2267** will be rolled back automatically. 2268** 2269** ^The sqlite3_interrupt(D) call is in effect until all currently running 2270** SQL statements on [database connection] D complete. ^Any new SQL statements 2271** that are started after the sqlite3_interrupt() call and before the 2272** running statements reaches zero are interrupted as if they had been 2273** running prior to the sqlite3_interrupt() call. ^New SQL statements 2274** that are started after the running statement count reaches zero are 2275** not effected by the sqlite3_interrupt(). 2276** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2277** SQL statements is a no-op and has no effect on SQL statements 2278** that are started after the sqlite3_interrupt() call returns. 2279*/ 2280void sqlite3_interrupt(sqlite3*); 2281 2282/* 2283** CAPI3REF: Determine If An SQL Statement Is Complete 2284** 2285** These routines are useful during command-line input to determine if the 2286** currently entered text seems to form a complete SQL statement or 2287** if additional input is needed before sending the text into 2288** SQLite for parsing. ^These routines return 1 if the input string 2289** appears to be a complete SQL statement. ^A statement is judged to be 2290** complete if it ends with a semicolon token and is not a prefix of a 2291** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2292** string literals or quoted identifier names or comments are not 2293** independent tokens (they are part of the token in which they are 2294** embedded) and thus do not count as a statement terminator. ^Whitespace 2295** and comments that follow the final semicolon are ignored. 2296** 2297** ^These routines return 0 if the statement is incomplete. ^If a 2298** memory allocation fails, then SQLITE_NOMEM is returned. 2299** 2300** ^These routines do not parse the SQL statements thus 2301** will not detect syntactically incorrect SQL. 2302** 2303** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2304** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2305** automatically by sqlite3_complete16(). If that initialization fails, 2306** then the return value from sqlite3_complete16() will be non-zero 2307** regardless of whether or not the input SQL is complete.)^ 2308** 2309** The input to [sqlite3_complete()] must be a zero-terminated 2310** UTF-8 string. 2311** 2312** The input to [sqlite3_complete16()] must be a zero-terminated 2313** UTF-16 string in native byte order. 2314*/ 2315int sqlite3_complete(const char *sql); 2316int sqlite3_complete16(const void *sql); 2317 2318/* 2319** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2320** KEYWORDS: {busy-handler callback} {busy handler} 2321** METHOD: sqlite3 2322** 2323** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2324** that might be invoked with argument P whenever 2325** an attempt is made to access a database table associated with 2326** [database connection] D when another thread 2327** or process has the table locked. 2328** The sqlite3_busy_handler() interface is used to implement 2329** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2330** 2331** ^If the busy callback is NULL, then [SQLITE_BUSY] 2332** is returned immediately upon encountering the lock. ^If the busy callback 2333** is not NULL, then the callback might be invoked with two arguments. 2334** 2335** ^The first argument to the busy handler is a copy of the void* pointer which 2336** is the third argument to sqlite3_busy_handler(). ^The second argument to 2337** the busy handler callback is the number of times that the busy handler has 2338** been invoked previously for the same locking event. ^If the 2339** busy callback returns 0, then no additional attempts are made to 2340** access the database and [SQLITE_BUSY] is returned 2341** to the application. 2342** ^If the callback returns non-zero, then another attempt 2343** is made to access the database and the cycle repeats. 2344** 2345** The presence of a busy handler does not guarantee that it will be invoked 2346** when there is lock contention. ^If SQLite determines that invoking the busy 2347** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2348** to the application instead of invoking the 2349** busy handler. 2350** Consider a scenario where one process is holding a read lock that 2351** it is trying to promote to a reserved lock and 2352** a second process is holding a reserved lock that it is trying 2353** to promote to an exclusive lock. The first process cannot proceed 2354** because it is blocked by the second and the second process cannot 2355** proceed because it is blocked by the first. If both processes 2356** invoke the busy handlers, neither will make any progress. Therefore, 2357** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2358** will induce the first process to release its read lock and allow 2359** the second process to proceed. 2360** 2361** ^The default busy callback is NULL. 2362** 2363** ^(There can only be a single busy handler defined for each 2364** [database connection]. Setting a new busy handler clears any 2365** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2366** or evaluating [PRAGMA busy_timeout=N] will change the 2367** busy handler and thus clear any previously set busy handler. 2368** 2369** The busy callback should not take any actions which modify the 2370** database connection that invoked the busy handler. In other words, 2371** the busy handler is not reentrant. Any such actions 2372** result in undefined behavior. 2373** 2374** A busy handler must not close the database connection 2375** or [prepared statement] that invoked the busy handler. 2376*/ 2377int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2378 2379/* 2380** CAPI3REF: Set A Busy Timeout 2381** METHOD: sqlite3 2382** 2383** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2384** for a specified amount of time when a table is locked. ^The handler 2385** will sleep multiple times until at least "ms" milliseconds of sleeping 2386** have accumulated. ^After at least "ms" milliseconds of sleeping, 2387** the handler returns 0 which causes [sqlite3_step()] to return 2388** [SQLITE_BUSY]. 2389** 2390** ^Calling this routine with an argument less than or equal to zero 2391** turns off all busy handlers. 2392** 2393** ^(There can only be a single busy handler for a particular 2394** [database connection] at any given moment. If another busy handler 2395** was defined (using [sqlite3_busy_handler()]) prior to calling 2396** this routine, that other busy handler is cleared.)^ 2397** 2398** See also: [PRAGMA busy_timeout] 2399*/ 2400int sqlite3_busy_timeout(sqlite3*, int ms); 2401 2402/* 2403** CAPI3REF: Convenience Routines For Running Queries 2404** METHOD: sqlite3 2405** 2406** This is a legacy interface that is preserved for backwards compatibility. 2407** Use of this interface is not recommended. 2408** 2409** Definition: A <b>result table</b> is memory data structure created by the 2410** [sqlite3_get_table()] interface. A result table records the 2411** complete query results from one or more queries. 2412** 2413** The table conceptually has a number of rows and columns. But 2414** these numbers are not part of the result table itself. These 2415** numbers are obtained separately. Let N be the number of rows 2416** and M be the number of columns. 2417** 2418** A result table is an array of pointers to zero-terminated UTF-8 strings. 2419** There are (N+1)*M elements in the array. The first M pointers point 2420** to zero-terminated strings that contain the names of the columns. 2421** The remaining entries all point to query results. NULL values result 2422** in NULL pointers. All other values are in their UTF-8 zero-terminated 2423** string representation as returned by [sqlite3_column_text()]. 2424** 2425** A result table might consist of one or more memory allocations. 2426** It is not safe to pass a result table directly to [sqlite3_free()]. 2427** A result table should be deallocated using [sqlite3_free_table()]. 2428** 2429** ^(As an example of the result table format, suppose a query result 2430** is as follows: 2431** 2432** <blockquote><pre> 2433** Name | Age 2434** ----------------------- 2435** Alice | 43 2436** Bob | 28 2437** Cindy | 21 2438** </pre></blockquote> 2439** 2440** There are two column (M==2) and three rows (N==3). Thus the 2441** result table has 8 entries. Suppose the result table is stored 2442** in an array names azResult. Then azResult holds this content: 2443** 2444** <blockquote><pre> 2445** azResult[0] = "Name"; 2446** azResult[1] = "Age"; 2447** azResult[2] = "Alice"; 2448** azResult[3] = "43"; 2449** azResult[4] = "Bob"; 2450** azResult[5] = "28"; 2451** azResult[6] = "Cindy"; 2452** azResult[7] = "21"; 2453** </pre></blockquote>)^ 2454** 2455** ^The sqlite3_get_table() function evaluates one or more 2456** semicolon-separated SQL statements in the zero-terminated UTF-8 2457** string of its 2nd parameter and returns a result table to the 2458** pointer given in its 3rd parameter. 2459** 2460** After the application has finished with the result from sqlite3_get_table(), 2461** it must pass the result table pointer to sqlite3_free_table() in order to 2462** release the memory that was malloced. Because of the way the 2463** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2464** function must not try to call [sqlite3_free()] directly. Only 2465** [sqlite3_free_table()] is able to release the memory properly and safely. 2466** 2467** The sqlite3_get_table() interface is implemented as a wrapper around 2468** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2469** to any internal data structures of SQLite. It uses only the public 2470** interface defined here. As a consequence, errors that occur in the 2471** wrapper layer outside of the internal [sqlite3_exec()] call are not 2472** reflected in subsequent calls to [sqlite3_errcode()] or 2473** [sqlite3_errmsg()]. 2474*/ 2475int sqlite3_get_table( 2476 sqlite3 *db, /* An open database */ 2477 const char *zSql, /* SQL to be evaluated */ 2478 char ***pazResult, /* Results of the query */ 2479 int *pnRow, /* Number of result rows written here */ 2480 int *pnColumn, /* Number of result columns written here */ 2481 char **pzErrmsg /* Error msg written here */ 2482); 2483void sqlite3_free_table(char **result); 2484 2485/* 2486** CAPI3REF: Formatted String Printing Functions 2487** 2488** These routines are work-alikes of the "printf()" family of functions 2489** from the standard C library. 2490** These routines understand most of the common K&R formatting options, 2491** plus some additional non-standard formats, detailed below. 2492** Note that some of the more obscure formatting options from recent 2493** C-library standards are omitted from this implementation. 2494** 2495** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2496** results into memory obtained from [sqlite3_malloc()]. 2497** The strings returned by these two routines should be 2498** released by [sqlite3_free()]. ^Both routines return a 2499** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2500** memory to hold the resulting string. 2501** 2502** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2503** the standard C library. The result is written into the 2504** buffer supplied as the second parameter whose size is given by 2505** the first parameter. Note that the order of the 2506** first two parameters is reversed from snprintf().)^ This is an 2507** historical accident that cannot be fixed without breaking 2508** backwards compatibility. ^(Note also that sqlite3_snprintf() 2509** returns a pointer to its buffer instead of the number of 2510** characters actually written into the buffer.)^ We admit that 2511** the number of characters written would be a more useful return 2512** value but we cannot change the implementation of sqlite3_snprintf() 2513** now without breaking compatibility. 2514** 2515** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2516** guarantees that the buffer is always zero-terminated. ^The first 2517** parameter "n" is the total size of the buffer, including space for 2518** the zero terminator. So the longest string that can be completely 2519** written will be n-1 characters. 2520** 2521** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2522** 2523** These routines all implement some additional formatting 2524** options that are useful for constructing SQL statements. 2525** All of the usual printf() formatting options apply. In addition, there 2526** is are "%q", "%Q", "%w" and "%z" options. 2527** 2528** ^(The %q option works like %s in that it substitutes a nul-terminated 2529** string from the argument list. But %q also doubles every '\'' character. 2530** %q is designed for use inside a string literal.)^ By doubling each '\'' 2531** character it escapes that character and allows it to be inserted into 2532** the string. 2533** 2534** For example, assume the string variable zText contains text as follows: 2535** 2536** <blockquote><pre> 2537** char *zText = "It's a happy day!"; 2538** </pre></blockquote> 2539** 2540** One can use this text in an SQL statement as follows: 2541** 2542** <blockquote><pre> 2543** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2544** sqlite3_exec(db, zSQL, 0, 0, 0); 2545** sqlite3_free(zSQL); 2546** </pre></blockquote> 2547** 2548** Because the %q format string is used, the '\'' character in zText 2549** is escaped and the SQL generated is as follows: 2550** 2551** <blockquote><pre> 2552** INSERT INTO table1 VALUES('It''s a happy day!') 2553** </pre></blockquote> 2554** 2555** This is correct. Had we used %s instead of %q, the generated SQL 2556** would have looked like this: 2557** 2558** <blockquote><pre> 2559** INSERT INTO table1 VALUES('It's a happy day!'); 2560** </pre></blockquote> 2561** 2562** This second example is an SQL syntax error. As a general rule you should 2563** always use %q instead of %s when inserting text into a string literal. 2564** 2565** ^(The %Q option works like %q except it also adds single quotes around 2566** the outside of the total string. Additionally, if the parameter in the 2567** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2568** single quotes).)^ So, for example, one could say: 2569** 2570** <blockquote><pre> 2571** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2572** sqlite3_exec(db, zSQL, 0, 0, 0); 2573** sqlite3_free(zSQL); 2574** </pre></blockquote> 2575** 2576** The code above will render a correct SQL statement in the zSQL 2577** variable even if the zText variable is a NULL pointer. 2578** 2579** ^(The "%w" formatting option is like "%q" except that it expects to 2580** be contained within double-quotes instead of single quotes, and it 2581** escapes the double-quote character instead of the single-quote 2582** character.)^ The "%w" formatting option is intended for safely inserting 2583** table and column names into a constructed SQL statement. 2584** 2585** ^(The "%z" formatting option works like "%s" but with the 2586** addition that after the string has been read and copied into 2587** the result, [sqlite3_free()] is called on the input string.)^ 2588*/ 2589char *sqlite3_mprintf(const char*,...); 2590char *sqlite3_vmprintf(const char*, va_list); 2591char *sqlite3_snprintf(int,char*,const char*, ...); 2592char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2593 2594/* 2595** CAPI3REF: Memory Allocation Subsystem 2596** 2597** The SQLite core uses these three routines for all of its own 2598** internal memory allocation needs. "Core" in the previous sentence 2599** does not include operating-system specific VFS implementation. The 2600** Windows VFS uses native malloc() and free() for some operations. 2601** 2602** ^The sqlite3_malloc() routine returns a pointer to a block 2603** of memory at least N bytes in length, where N is the parameter. 2604** ^If sqlite3_malloc() is unable to obtain sufficient free 2605** memory, it returns a NULL pointer. ^If the parameter N to 2606** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2607** a NULL pointer. 2608** 2609** ^The sqlite3_malloc64(N) routine works just like 2610** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2611** of a signed 32-bit integer. 2612** 2613** ^Calling sqlite3_free() with a pointer previously returned 2614** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2615** that it might be reused. ^The sqlite3_free() routine is 2616** a no-op if is called with a NULL pointer. Passing a NULL pointer 2617** to sqlite3_free() is harmless. After being freed, memory 2618** should neither be read nor written. Even reading previously freed 2619** memory might result in a segmentation fault or other severe error. 2620** Memory corruption, a segmentation fault, or other severe error 2621** might result if sqlite3_free() is called with a non-NULL pointer that 2622** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2623** 2624** ^The sqlite3_realloc(X,N) interface attempts to resize a 2625** prior memory allocation X to be at least N bytes. 2626** ^If the X parameter to sqlite3_realloc(X,N) 2627** is a NULL pointer then its behavior is identical to calling 2628** sqlite3_malloc(N). 2629** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2630** negative then the behavior is exactly the same as calling 2631** sqlite3_free(X). 2632** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2633** of at least N bytes in size or NULL if insufficient memory is available. 2634** ^If M is the size of the prior allocation, then min(N,M) bytes 2635** of the prior allocation are copied into the beginning of buffer returned 2636** by sqlite3_realloc(X,N) and the prior allocation is freed. 2637** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2638** prior allocation is not freed. 2639** 2640** ^The sqlite3_realloc64(X,N) interfaces works the same as 2641** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2642** of a 32-bit signed integer. 2643** 2644** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2645** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2646** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2647** ^The value returned by sqlite3_msize(X) might be larger than the number 2648** of bytes requested when X was allocated. ^If X is a NULL pointer then 2649** sqlite3_msize(X) returns zero. If X points to something that is not 2650** the beginning of memory allocation, or if it points to a formerly 2651** valid memory allocation that has now been freed, then the behavior 2652** of sqlite3_msize(X) is undefined and possibly harmful. 2653** 2654** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2655** sqlite3_malloc64(), and sqlite3_realloc64() 2656** is always aligned to at least an 8 byte boundary, or to a 2657** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2658** option is used. 2659** 2660** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2661** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2662** implementation of these routines to be omitted. That capability 2663** is no longer provided. Only built-in memory allocators can be used. 2664** 2665** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2666** the system malloc() and free() directly when converting 2667** filenames between the UTF-8 encoding used by SQLite 2668** and whatever filename encoding is used by the particular Windows 2669** installation. Memory allocation errors were detected, but 2670** they were reported back as [SQLITE_CANTOPEN] or 2671** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2672** 2673** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2674** must be either NULL or else pointers obtained from a prior 2675** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2676** not yet been released. 2677** 2678** The application must not read or write any part of 2679** a block of memory after it has been released using 2680** [sqlite3_free()] or [sqlite3_realloc()]. 2681*/ 2682void *sqlite3_malloc(int); 2683void *sqlite3_malloc64(sqlite3_uint64); 2684void *sqlite3_realloc(void*, int); 2685void *sqlite3_realloc64(void*, sqlite3_uint64); 2686void sqlite3_free(void*); 2687sqlite3_uint64 sqlite3_msize(void*); 2688 2689/* 2690** CAPI3REF: Memory Allocator Statistics 2691** 2692** SQLite provides these two interfaces for reporting on the status 2693** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2694** routines, which form the built-in memory allocation subsystem. 2695** 2696** ^The [sqlite3_memory_used()] routine returns the number of bytes 2697** of memory currently outstanding (malloced but not freed). 2698** ^The [sqlite3_memory_highwater()] routine returns the maximum 2699** value of [sqlite3_memory_used()] since the high-water mark 2700** was last reset. ^The values returned by [sqlite3_memory_used()] and 2701** [sqlite3_memory_highwater()] include any overhead 2702** added by SQLite in its implementation of [sqlite3_malloc()], 2703** but not overhead added by the any underlying system library 2704** routines that [sqlite3_malloc()] may call. 2705** 2706** ^The memory high-water mark is reset to the current value of 2707** [sqlite3_memory_used()] if and only if the parameter to 2708** [sqlite3_memory_highwater()] is true. ^The value returned 2709** by [sqlite3_memory_highwater(1)] is the high-water mark 2710** prior to the reset. 2711*/ 2712sqlite3_int64 sqlite3_memory_used(void); 2713sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2714 2715/* 2716** CAPI3REF: Pseudo-Random Number Generator 2717** 2718** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2719** select random [ROWID | ROWIDs] when inserting new records into a table that 2720** already uses the largest possible [ROWID]. The PRNG is also used for 2721** the build-in random() and randomblob() SQL functions. This interface allows 2722** applications to access the same PRNG for other purposes. 2723** 2724** ^A call to this routine stores N bytes of randomness into buffer P. 2725** ^The P parameter can be a NULL pointer. 2726** 2727** ^If this routine has not been previously called or if the previous 2728** call had N less than one or a NULL pointer for P, then the PRNG is 2729** seeded using randomness obtained from the xRandomness method of 2730** the default [sqlite3_vfs] object. 2731** ^If the previous call to this routine had an N of 1 or more and a 2732** non-NULL P then the pseudo-randomness is generated 2733** internally and without recourse to the [sqlite3_vfs] xRandomness 2734** method. 2735*/ 2736void sqlite3_randomness(int N, void *P); 2737 2738/* 2739** CAPI3REF: Compile-Time Authorization Callbacks 2740** METHOD: sqlite3 2741** KEYWORDS: {authorizer callback} 2742** 2743** ^This routine registers an authorizer callback with a particular 2744** [database connection], supplied in the first argument. 2745** ^The authorizer callback is invoked as SQL statements are being compiled 2746** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2747** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2748** and [sqlite3_prepare16_v3()]. ^At various 2749** points during the compilation process, as logic is being created 2750** to perform various actions, the authorizer callback is invoked to 2751** see if those actions are allowed. ^The authorizer callback should 2752** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2753** specific action but allow the SQL statement to continue to be 2754** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2755** rejected with an error. ^If the authorizer callback returns 2756** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2757** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2758** the authorizer will fail with an error message. 2759** 2760** When the callback returns [SQLITE_OK], that means the operation 2761** requested is ok. ^When the callback returns [SQLITE_DENY], the 2762** [sqlite3_prepare_v2()] or equivalent call that triggered the 2763** authorizer will fail with an error message explaining that 2764** access is denied. 2765** 2766** ^The first parameter to the authorizer callback is a copy of the third 2767** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2768** to the callback is an integer [SQLITE_COPY | action code] that specifies 2769** the particular action to be authorized. ^The third through sixth parameters 2770** to the callback are either NULL pointers or zero-terminated strings 2771** that contain additional details about the action to be authorized. 2772** Applications must always be prepared to encounter a NULL pointer in any 2773** of the third through the sixth parameters of the authorization callback. 2774** 2775** ^If the action code is [SQLITE_READ] 2776** and the callback returns [SQLITE_IGNORE] then the 2777** [prepared statement] statement is constructed to substitute 2778** a NULL value in place of the table column that would have 2779** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2780** return can be used to deny an untrusted user access to individual 2781** columns of a table. 2782** ^When a table is referenced by a [SELECT] but no column values are 2783** extracted from that table (for example in a query like 2784** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2785** is invoked once for that table with a column name that is an empty string. 2786** ^If the action code is [SQLITE_DELETE] and the callback returns 2787** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2788** [truncate optimization] is disabled and all rows are deleted individually. 2789** 2790** An authorizer is used when [sqlite3_prepare | preparing] 2791** SQL statements from an untrusted source, to ensure that the SQL statements 2792** do not try to access data they are not allowed to see, or that they do not 2793** try to execute malicious statements that damage the database. For 2794** example, an application may allow a user to enter arbitrary 2795** SQL queries for evaluation by a database. But the application does 2796** not want the user to be able to make arbitrary changes to the 2797** database. An authorizer could then be put in place while the 2798** user-entered SQL is being [sqlite3_prepare | prepared] that 2799** disallows everything except [SELECT] statements. 2800** 2801** Applications that need to process SQL from untrusted sources 2802** might also consider lowering resource limits using [sqlite3_limit()] 2803** and limiting database size using the [max_page_count] [PRAGMA] 2804** in addition to using an authorizer. 2805** 2806** ^(Only a single authorizer can be in place on a database connection 2807** at a time. Each call to sqlite3_set_authorizer overrides the 2808** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2809** The authorizer is disabled by default. 2810** 2811** The authorizer callback must not do anything that will modify 2812** the database connection that invoked the authorizer callback. 2813** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2814** database connections for the meaning of "modify" in this paragraph. 2815** 2816** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2817** statement might be re-prepared during [sqlite3_step()] due to a 2818** schema change. Hence, the application should ensure that the 2819** correct authorizer callback remains in place during the [sqlite3_step()]. 2820** 2821** ^Note that the authorizer callback is invoked only during 2822** [sqlite3_prepare()] or its variants. Authorization is not 2823** performed during statement evaluation in [sqlite3_step()], unless 2824** as stated in the previous paragraph, sqlite3_step() invokes 2825** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2826*/ 2827int sqlite3_set_authorizer( 2828 sqlite3*, 2829 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2830 void *pUserData 2831); 2832 2833/* 2834** CAPI3REF: Authorizer Return Codes 2835** 2836** The [sqlite3_set_authorizer | authorizer callback function] must 2837** return either [SQLITE_OK] or one of these two constants in order 2838** to signal SQLite whether or not the action is permitted. See the 2839** [sqlite3_set_authorizer | authorizer documentation] for additional 2840** information. 2841** 2842** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2843** returned from the [sqlite3_vtab_on_conflict()] interface. 2844*/ 2845#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2846#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2847 2848/* 2849** CAPI3REF: Authorizer Action Codes 2850** 2851** The [sqlite3_set_authorizer()] interface registers a callback function 2852** that is invoked to authorize certain SQL statement actions. The 2853** second parameter to the callback is an integer code that specifies 2854** what action is being authorized. These are the integer action codes that 2855** the authorizer callback may be passed. 2856** 2857** These action code values signify what kind of operation is to be 2858** authorized. The 3rd and 4th parameters to the authorization 2859** callback function will be parameters or NULL depending on which of these 2860** codes is used as the second parameter. ^(The 5th parameter to the 2861** authorizer callback is the name of the database ("main", "temp", 2862** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2863** is the name of the inner-most trigger or view that is responsible for 2864** the access attempt or NULL if this access attempt is directly from 2865** top-level SQL code. 2866*/ 2867/******************************************* 3rd ************ 4th ***********/ 2868#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2869#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2870#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2871#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2872#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2873#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2874#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2875#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2876#define SQLITE_DELETE 9 /* Table Name NULL */ 2877#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2878#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2879#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2880#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2881#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2882#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2883#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2884#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2885#define SQLITE_INSERT 18 /* Table Name NULL */ 2886#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2887#define SQLITE_READ 20 /* Table Name Column Name */ 2888#define SQLITE_SELECT 21 /* NULL NULL */ 2889#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2890#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2891#define SQLITE_ATTACH 24 /* Filename NULL */ 2892#define SQLITE_DETACH 25 /* Database Name NULL */ 2893#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2894#define SQLITE_REINDEX 27 /* Index Name NULL */ 2895#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2896#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2897#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2898#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2899#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2900#define SQLITE_COPY 0 /* No longer used */ 2901#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2902 2903/* 2904** CAPI3REF: Tracing And Profiling Functions 2905** METHOD: sqlite3 2906** 2907** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2908** instead of the routines described here. 2909** 2910** These routines register callback functions that can be used for 2911** tracing and profiling the execution of SQL statements. 2912** 2913** ^The callback function registered by sqlite3_trace() is invoked at 2914** various times when an SQL statement is being run by [sqlite3_step()]. 2915** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2916** SQL statement text as the statement first begins executing. 2917** ^(Additional sqlite3_trace() callbacks might occur 2918** as each triggered subprogram is entered. The callbacks for triggers 2919** contain a UTF-8 SQL comment that identifies the trigger.)^ 2920** 2921** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2922** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2923** 2924** ^The callback function registered by sqlite3_profile() is invoked 2925** as each SQL statement finishes. ^The profile callback contains 2926** the original statement text and an estimate of wall-clock time 2927** of how long that statement took to run. ^The profile callback 2928** time is in units of nanoseconds, however the current implementation 2929** is only capable of millisecond resolution so the six least significant 2930** digits in the time are meaningless. Future versions of SQLite 2931** might provide greater resolution on the profiler callback. The 2932** sqlite3_profile() function is considered experimental and is 2933** subject to change in future versions of SQLite. 2934*/ 2935SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2936 void(*xTrace)(void*,const char*), void*); 2937SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2938 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2939 2940/* 2941** CAPI3REF: SQL Trace Event Codes 2942** KEYWORDS: SQLITE_TRACE 2943** 2944** These constants identify classes of events that can be monitored 2945** using the [sqlite3_trace_v2()] tracing logic. The third argument 2946** to [sqlite3_trace_v2()] is an OR-ed combination of one or more of 2947** the following constants. ^The first argument to the trace callback 2948** is one of the following constants. 2949** 2950** New tracing constants may be added in future releases. 2951** 2952** ^A trace callback has four arguments: xCallback(T,C,P,X). 2953** ^The T argument is one of the integer type codes above. 2954** ^The C argument is a copy of the context pointer passed in as the 2955** fourth argument to [sqlite3_trace_v2()]. 2956** The P and X arguments are pointers whose meanings depend on T. 2957** 2958** <dl> 2959** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2960** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2961** first begins running and possibly at other times during the 2962** execution of the prepared statement, such as at the start of each 2963** trigger subprogram. ^The P argument is a pointer to the 2964** [prepared statement]. ^The X argument is a pointer to a string which 2965** is the unexpanded SQL text of the prepared statement or an SQL comment 2966** that indicates the invocation of a trigger. ^The callback can compute 2967** the same text that would have been returned by the legacy [sqlite3_trace()] 2968** interface by using the X argument when X begins with "--" and invoking 2969** [sqlite3_expanded_sql(P)] otherwise. 2970** 2971** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2972** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2973** information as is provided by the [sqlite3_profile()] callback. 2974** ^The P argument is a pointer to the [prepared statement] and the 2975** X argument points to a 64-bit integer which is the estimated of 2976** the number of nanosecond that the prepared statement took to run. 2977** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2978** 2979** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2980** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2981** statement generates a single row of result. 2982** ^The P argument is a pointer to the [prepared statement] and the 2983** X argument is unused. 2984** 2985** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2986** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2987** connection closes. 2988** ^The P argument is a pointer to the [database connection] object 2989** and the X argument is unused. 2990** </dl> 2991*/ 2992#define SQLITE_TRACE_STMT 0x01 2993#define SQLITE_TRACE_PROFILE 0x02 2994#define SQLITE_TRACE_ROW 0x04 2995#define SQLITE_TRACE_CLOSE 0x08 2996 2997/* 2998** CAPI3REF: SQL Trace Hook 2999** METHOD: sqlite3 3000** 3001** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3002** function X against [database connection] D, using property mask M 3003** and context pointer P. ^If the X callback is 3004** NULL or if the M mask is zero, then tracing is disabled. The 3005** M argument should be the bitwise OR-ed combination of 3006** zero or more [SQLITE_TRACE] constants. 3007** 3008** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3009** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3010** 3011** ^The X callback is invoked whenever any of the events identified by 3012** mask M occur. ^The integer return value from the callback is currently 3013** ignored, though this may change in future releases. Callback 3014** implementations should return zero to ensure future compatibility. 3015** 3016** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3017** ^The T argument is one of the [SQLITE_TRACE] 3018** constants to indicate why the callback was invoked. 3019** ^The C argument is a copy of the context pointer. 3020** The P and X arguments are pointers whose meanings depend on T. 3021** 3022** The sqlite3_trace_v2() interface is intended to replace the legacy 3023** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3024** are deprecated. 3025*/ 3026int sqlite3_trace_v2( 3027 sqlite3*, 3028 unsigned uMask, 3029 int(*xCallback)(unsigned,void*,void*,void*), 3030 void *pCtx 3031); 3032 3033/* 3034** CAPI3REF: Query Progress Callbacks 3035** METHOD: sqlite3 3036** 3037** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3038** function X to be invoked periodically during long running calls to 3039** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3040** database connection D. An example use for this 3041** interface is to keep a GUI updated during a large query. 3042** 3043** ^The parameter P is passed through as the only parameter to the 3044** callback function X. ^The parameter N is the approximate number of 3045** [virtual machine instructions] that are evaluated between successive 3046** invocations of the callback X. ^If N is less than one then the progress 3047** handler is disabled. 3048** 3049** ^Only a single progress handler may be defined at one time per 3050** [database connection]; setting a new progress handler cancels the 3051** old one. ^Setting parameter X to NULL disables the progress handler. 3052** ^The progress handler is also disabled by setting N to a value less 3053** than 1. 3054** 3055** ^If the progress callback returns non-zero, the operation is 3056** interrupted. This feature can be used to implement a 3057** "Cancel" button on a GUI progress dialog box. 3058** 3059** The progress handler callback must not do anything that will modify 3060** the database connection that invoked the progress handler. 3061** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3062** database connections for the meaning of "modify" in this paragraph. 3063** 3064*/ 3065void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3066 3067/* 3068** CAPI3REF: Opening A New Database Connection 3069** CONSTRUCTOR: sqlite3 3070** 3071** ^These routines open an SQLite database file as specified by the 3072** filename argument. ^The filename argument is interpreted as UTF-8 for 3073** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3074** order for sqlite3_open16(). ^(A [database connection] handle is usually 3075** returned in *ppDb, even if an error occurs. The only exception is that 3076** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3077** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3078** object.)^ ^(If the database is opened (and/or created) successfully, then 3079** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3080** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3081** an English language description of the error following a failure of any 3082** of the sqlite3_open() routines. 3083** 3084** ^The default encoding will be UTF-8 for databases created using 3085** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3086** created using sqlite3_open16() will be UTF-16 in the native byte order. 3087** 3088** Whether or not an error occurs when it is opened, resources 3089** associated with the [database connection] handle should be released by 3090** passing it to [sqlite3_close()] when it is no longer required. 3091** 3092** The sqlite3_open_v2() interface works like sqlite3_open() 3093** except that it accepts two additional parameters for additional control 3094** over the new database connection. ^(The flags parameter to 3095** sqlite3_open_v2() can take one of 3096** the following three values, optionally combined with the 3097** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3098** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3099** 3100** <dl> 3101** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3102** <dd>The database is opened in read-only mode. If the database does not 3103** already exist, an error is returned.</dd>)^ 3104** 3105** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3106** <dd>The database is opened for reading and writing if possible, or reading 3107** only if the file is write protected by the operating system. In either 3108** case the database must already exist, otherwise an error is returned.</dd>)^ 3109** 3110** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3111** <dd>The database is opened for reading and writing, and is created if 3112** it does not already exist. This is the behavior that is always used for 3113** sqlite3_open() and sqlite3_open16().</dd>)^ 3114** </dl> 3115** 3116** If the 3rd parameter to sqlite3_open_v2() is not one of the 3117** combinations shown above optionally combined with other 3118** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3119** then the behavior is undefined. 3120** 3121** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3122** opens in the multi-thread [threading mode] as long as the single-thread 3123** mode has not been set at compile-time or start-time. ^If the 3124** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3125** in the serialized [threading mode] unless single-thread was 3126** previously selected at compile-time or start-time. 3127** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3128** eligible to use [shared cache mode], regardless of whether or not shared 3129** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3130** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3131** participate in [shared cache mode] even if it is enabled. 3132** 3133** ^The fourth parameter to sqlite3_open_v2() is the name of the 3134** [sqlite3_vfs] object that defines the operating system interface that 3135** the new database connection should use. ^If the fourth parameter is 3136** a NULL pointer then the default [sqlite3_vfs] object is used. 3137** 3138** ^If the filename is ":memory:", then a private, temporary in-memory database 3139** is created for the connection. ^This in-memory database will vanish when 3140** the database connection is closed. Future versions of SQLite might 3141** make use of additional special filenames that begin with the ":" character. 3142** It is recommended that when a database filename actually does begin with 3143** a ":" character you should prefix the filename with a pathname such as 3144** "./" to avoid ambiguity. 3145** 3146** ^If the filename is an empty string, then a private, temporary 3147** on-disk database will be created. ^This private database will be 3148** automatically deleted as soon as the database connection is closed. 3149** 3150** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3151** 3152** ^If [URI filename] interpretation is enabled, and the filename argument 3153** begins with "file:", then the filename is interpreted as a URI. ^URI 3154** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3155** set in the third argument to sqlite3_open_v2(), or if it has 3156** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3157** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3158** URI filename interpretation is turned off 3159** by default, but future releases of SQLite might enable URI filename 3160** interpretation by default. See "[URI filenames]" for additional 3161** information. 3162** 3163** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3164** authority, then it must be either an empty string or the string 3165** "localhost". ^If the authority is not an empty string or "localhost", an 3166** error is returned to the caller. ^The fragment component of a URI, if 3167** present, is ignored. 3168** 3169** ^SQLite uses the path component of the URI as the name of the disk file 3170** which contains the database. ^If the path begins with a '/' character, 3171** then it is interpreted as an absolute path. ^If the path does not begin 3172** with a '/' (meaning that the authority section is omitted from the URI) 3173** then the path is interpreted as a relative path. 3174** ^(On windows, the first component of an absolute path 3175** is a drive specification (e.g. "C:").)^ 3176** 3177** [[core URI query parameters]] 3178** The query component of a URI may contain parameters that are interpreted 3179** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3180** SQLite and its built-in [VFSes] interpret the 3181** following query parameters: 3182** 3183** <ul> 3184** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3185** a VFS object that provides the operating system interface that should 3186** be used to access the database file on disk. ^If this option is set to 3187** an empty string the default VFS object is used. ^Specifying an unknown 3188** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3189** present, then the VFS specified by the option takes precedence over 3190** the value passed as the fourth parameter to sqlite3_open_v2(). 3191** 3192** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3193** "rwc", or "memory". Attempting to set it to any other value is 3194** an error)^. 3195** ^If "ro" is specified, then the database is opened for read-only 3196** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3197** third argument to sqlite3_open_v2(). ^If the mode option is set to 3198** "rw", then the database is opened for read-write (but not create) 3199** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3200** been set. ^Value "rwc" is equivalent to setting both 3201** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3202** set to "memory" then a pure [in-memory database] that never reads 3203** or writes from disk is used. ^It is an error to specify a value for 3204** the mode parameter that is less restrictive than that specified by 3205** the flags passed in the third parameter to sqlite3_open_v2(). 3206** 3207** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3208** "private". ^Setting it to "shared" is equivalent to setting the 3209** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3210** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3211** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3212** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3213** a URI filename, its value overrides any behavior requested by setting 3214** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3215** 3216** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3217** [powersafe overwrite] property does or does not apply to the 3218** storage media on which the database file resides. 3219** 3220** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3221** which if set disables file locking in rollback journal modes. This 3222** is useful for accessing a database on a filesystem that does not 3223** support locking. Caution: Database corruption might result if two 3224** or more processes write to the same database and any one of those 3225** processes uses nolock=1. 3226** 3227** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3228** parameter that indicates that the database file is stored on 3229** read-only media. ^When immutable is set, SQLite assumes that the 3230** database file cannot be changed, even by a process with higher 3231** privilege, and so the database is opened read-only and all locking 3232** and change detection is disabled. Caution: Setting the immutable 3233** property on a database file that does in fact change can result 3234** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3235** See also: [SQLITE_IOCAP_IMMUTABLE]. 3236** 3237** </ul> 3238** 3239** ^Specifying an unknown parameter in the query component of a URI is not an 3240** error. Future versions of SQLite might understand additional query 3241** parameters. See "[query parameters with special meaning to SQLite]" for 3242** additional information. 3243** 3244** [[URI filename examples]] <h3>URI filename examples</h3> 3245** 3246** <table border="1" align=center cellpadding=5> 3247** <tr><th> URI filenames <th> Results 3248** <tr><td> file:data.db <td> 3249** Open the file "data.db" in the current directory. 3250** <tr><td> file:/home/fred/data.db<br> 3251** file:///home/fred/data.db <br> 3252** file://localhost/home/fred/data.db <br> <td> 3253** Open the database file "/home/fred/data.db". 3254** <tr><td> file://darkstar/home/fred/data.db <td> 3255** An error. "darkstar" is not a recognized authority. 3256** <tr><td style="white-space:nowrap"> 3257** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3258** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3259** C:. Note that the %20 escaping in this example is not strictly 3260** necessary - space characters can be used literally 3261** in URI filenames. 3262** <tr><td> file:data.db?mode=ro&cache=private <td> 3263** Open file "data.db" in the current directory for read-only access. 3264** Regardless of whether or not shared-cache mode is enabled by 3265** default, use a private cache. 3266** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3267** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3268** that uses dot-files in place of posix advisory locking. 3269** <tr><td> file:data.db?mode=readonly <td> 3270** An error. "readonly" is not a valid option for the "mode" parameter. 3271** </table> 3272** 3273** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3274** query components of a URI. A hexadecimal escape sequence consists of a 3275** percent sign - "%" - followed by exactly two hexadecimal digits 3276** specifying an octet value. ^Before the path or query components of a 3277** URI filename are interpreted, they are encoded using UTF-8 and all 3278** hexadecimal escape sequences replaced by a single byte containing the 3279** corresponding octet. If this process generates an invalid UTF-8 encoding, 3280** the results are undefined. 3281** 3282** <b>Note to Windows users:</b> The encoding used for the filename argument 3283** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3284** codepage is currently defined. Filenames containing international 3285** characters must be converted to UTF-8 prior to passing them into 3286** sqlite3_open() or sqlite3_open_v2(). 3287** 3288** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3289** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3290** features that require the use of temporary files may fail. 3291** 3292** See also: [sqlite3_temp_directory] 3293*/ 3294int sqlite3_open( 3295 const char *filename, /* Database filename (UTF-8) */ 3296 sqlite3 **ppDb /* OUT: SQLite db handle */ 3297); 3298int sqlite3_open16( 3299 const void *filename, /* Database filename (UTF-16) */ 3300 sqlite3 **ppDb /* OUT: SQLite db handle */ 3301); 3302int sqlite3_open_v2( 3303 const char *filename, /* Database filename (UTF-8) */ 3304 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3305 int flags, /* Flags */ 3306 const char *zVfs /* Name of VFS module to use */ 3307); 3308 3309/* 3310** CAPI3REF: Obtain Values For URI Parameters 3311** 3312** These are utility routines, useful to VFS implementations, that check 3313** to see if a database file was a URI that contained a specific query 3314** parameter, and if so obtains the value of that query parameter. 3315** 3316** If F is the database filename pointer passed into the xOpen() method of 3317** a VFS implementation when the flags parameter to xOpen() has one or 3318** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3319** P is the name of the query parameter, then 3320** sqlite3_uri_parameter(F,P) returns the value of the P 3321** parameter if it exists or a NULL pointer if P does not appear as a 3322** query parameter on F. If P is a query parameter of F 3323** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3324** a pointer to an empty string. 3325** 3326** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3327** parameter and returns true (1) or false (0) according to the value 3328** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3329** value of query parameter P is one of "yes", "true", or "on" in any 3330** case or if the value begins with a non-zero number. The 3331** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3332** query parameter P is one of "no", "false", or "off" in any case or 3333** if the value begins with a numeric zero. If P is not a query 3334** parameter on F or if the value of P is does not match any of the 3335** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3336** 3337** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3338** 64-bit signed integer and returns that integer, or D if P does not 3339** exist. If the value of P is something other than an integer, then 3340** zero is returned. 3341** 3342** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3343** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3344** is not a database file pathname pointer that SQLite passed into the xOpen 3345** VFS method, then the behavior of this routine is undefined and probably 3346** undesirable. 3347*/ 3348const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3349int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3350sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3351 3352 3353/* 3354** CAPI3REF: Error Codes And Messages 3355** METHOD: sqlite3 3356** 3357** ^If the most recent sqlite3_* API call associated with 3358** [database connection] D failed, then the sqlite3_errcode(D) interface 3359** returns the numeric [result code] or [extended result code] for that 3360** API call. 3361** If the most recent API call was successful, 3362** then the return value from sqlite3_errcode() is undefined. 3363** ^The sqlite3_extended_errcode() 3364** interface is the same except that it always returns the 3365** [extended result code] even when extended result codes are 3366** disabled. 3367** 3368** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3369** text that describes the error, as either UTF-8 or UTF-16 respectively. 3370** ^(Memory to hold the error message string is managed internally. 3371** The application does not need to worry about freeing the result. 3372** However, the error string might be overwritten or deallocated by 3373** subsequent calls to other SQLite interface functions.)^ 3374** 3375** ^The sqlite3_errstr() interface returns the English-language text 3376** that describes the [result code], as UTF-8. 3377** ^(Memory to hold the error message string is managed internally 3378** and must not be freed by the application)^. 3379** 3380** When the serialized [threading mode] is in use, it might be the 3381** case that a second error occurs on a separate thread in between 3382** the time of the first error and the call to these interfaces. 3383** When that happens, the second error will be reported since these 3384** interfaces always report the most recent result. To avoid 3385** this, each thread can obtain exclusive use of the [database connection] D 3386** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3387** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3388** all calls to the interfaces listed here are completed. 3389** 3390** If an interface fails with SQLITE_MISUSE, that means the interface 3391** was invoked incorrectly by the application. In that case, the 3392** error code and message may or may not be set. 3393*/ 3394int sqlite3_errcode(sqlite3 *db); 3395int sqlite3_extended_errcode(sqlite3 *db); 3396const char *sqlite3_errmsg(sqlite3*); 3397const void *sqlite3_errmsg16(sqlite3*); 3398const char *sqlite3_errstr(int); 3399 3400/* 3401** CAPI3REF: Prepared Statement Object 3402** KEYWORDS: {prepared statement} {prepared statements} 3403** 3404** An instance of this object represents a single SQL statement that 3405** has been compiled into binary form and is ready to be evaluated. 3406** 3407** Think of each SQL statement as a separate computer program. The 3408** original SQL text is source code. A prepared statement object 3409** is the compiled object code. All SQL must be converted into a 3410** prepared statement before it can be run. 3411** 3412** The life-cycle of a prepared statement object usually goes like this: 3413** 3414** <ol> 3415** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3416** <li> Bind values to [parameters] using the sqlite3_bind_*() 3417** interfaces. 3418** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3419** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3420** to step 2. Do this zero or more times. 3421** <li> Destroy the object using [sqlite3_finalize()]. 3422** </ol> 3423*/ 3424typedef struct sqlite3_stmt sqlite3_stmt; 3425 3426/* 3427** CAPI3REF: Run-time Limits 3428** METHOD: sqlite3 3429** 3430** ^(This interface allows the size of various constructs to be limited 3431** on a connection by connection basis. The first parameter is the 3432** [database connection] whose limit is to be set or queried. The 3433** second parameter is one of the [limit categories] that define a 3434** class of constructs to be size limited. The third parameter is the 3435** new limit for that construct.)^ 3436** 3437** ^If the new limit is a negative number, the limit is unchanged. 3438** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3439** [limits | hard upper bound] 3440** set at compile-time by a C preprocessor macro called 3441** [limits | SQLITE_MAX_<i>NAME</i>]. 3442** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3443** ^Attempts to increase a limit above its hard upper bound are 3444** silently truncated to the hard upper bound. 3445** 3446** ^Regardless of whether or not the limit was changed, the 3447** [sqlite3_limit()] interface returns the prior value of the limit. 3448** ^Hence, to find the current value of a limit without changing it, 3449** simply invoke this interface with the third parameter set to -1. 3450** 3451** Run-time limits are intended for use in applications that manage 3452** both their own internal database and also databases that are controlled 3453** by untrusted external sources. An example application might be a 3454** web browser that has its own databases for storing history and 3455** separate databases controlled by JavaScript applications downloaded 3456** off the Internet. The internal databases can be given the 3457** large, default limits. Databases managed by external sources can 3458** be given much smaller limits designed to prevent a denial of service 3459** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3460** interface to further control untrusted SQL. The size of the database 3461** created by an untrusted script can be contained using the 3462** [max_page_count] [PRAGMA]. 3463** 3464** New run-time limit categories may be added in future releases. 3465*/ 3466int sqlite3_limit(sqlite3*, int id, int newVal); 3467 3468/* 3469** CAPI3REF: Run-Time Limit Categories 3470** KEYWORDS: {limit category} {*limit categories} 3471** 3472** These constants define various performance limits 3473** that can be lowered at run-time using [sqlite3_limit()]. 3474** The synopsis of the meanings of the various limits is shown below. 3475** Additional information is available at [limits | Limits in SQLite]. 3476** 3477** <dl> 3478** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3479** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3480** 3481** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3482** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3483** 3484** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3485** <dd>The maximum number of columns in a table definition or in the 3486** result set of a [SELECT] or the maximum number of columns in an index 3487** or in an ORDER BY or GROUP BY clause.</dd>)^ 3488** 3489** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3490** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3491** 3492** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3493** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3494** 3495** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3496** <dd>The maximum number of instructions in a virtual machine program 3497** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3498** the equivalent tries to allocate space for more than this many opcodes 3499** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3500** 3501** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3502** <dd>The maximum number of arguments on a function.</dd>)^ 3503** 3504** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3505** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3506** 3507** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3508** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3509** <dd>The maximum length of the pattern argument to the [LIKE] or 3510** [GLOB] operators.</dd>)^ 3511** 3512** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3513** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3514** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3515** 3516** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3517** <dd>The maximum depth of recursion for triggers.</dd>)^ 3518** 3519** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3520** <dd>The maximum number of auxiliary worker threads that a single 3521** [prepared statement] may start.</dd>)^ 3522** </dl> 3523*/ 3524#define SQLITE_LIMIT_LENGTH 0 3525#define SQLITE_LIMIT_SQL_LENGTH 1 3526#define SQLITE_LIMIT_COLUMN 2 3527#define SQLITE_LIMIT_EXPR_DEPTH 3 3528#define SQLITE_LIMIT_COMPOUND_SELECT 4 3529#define SQLITE_LIMIT_VDBE_OP 5 3530#define SQLITE_LIMIT_FUNCTION_ARG 6 3531#define SQLITE_LIMIT_ATTACHED 7 3532#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3533#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3534#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3535#define SQLITE_LIMIT_WORKER_THREADS 11 3536 3537/* 3538** CAPI3REF: Prepare Flags 3539** 3540** These constants define various flags that can be passed into 3541** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3542** [sqlite3_prepare16_v3()] interfaces. 3543** 3544** New flags may be added in future releases of SQLite. 3545** 3546** <dl> 3547** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3548** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3549** that the prepared statement will be retained for a long time and 3550** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3551** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3552** be used just once or at most a few times and then destroyed using 3553** [sqlite3_finalize()] relatively soon. The current implementation acts 3554** on this hint by avoiding the use of [lookaside memory] so as not to 3555** deplete the limited store of lookaside memory. Future versions of 3556** SQLite may act on this hint differently. 3557** </dl> 3558*/ 3559#define SQLITE_PREPARE_PERSISTENT 0x01 3560 3561/* 3562** CAPI3REF: Compiling An SQL Statement 3563** KEYWORDS: {SQL statement compiler} 3564** METHOD: sqlite3 3565** CONSTRUCTOR: sqlite3_stmt 3566** 3567** To execute an SQL statement, it must first be compiled into a byte-code 3568** program using one of these routines. Or, in other words, these routines 3569** are constructors for the [prepared statement] object. 3570** 3571** The preferred routine to use is [sqlite3_prepare_v2()]. The 3572** [sqlite3_prepare()] interface is legacy and should be avoided. 3573** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3574** for special purposes. 3575** 3576** The use of the UTF-8 interfaces is preferred, as SQLite currently 3577** does all parsing using UTF-8. The UTF-16 interfaces are provided 3578** as a convenience. The UTF-16 interfaces work by converting the 3579** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3580** 3581** The first argument, "db", is a [database connection] obtained from a 3582** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3583** [sqlite3_open16()]. The database connection must not have been closed. 3584** 3585** The second argument, "zSql", is the statement to be compiled, encoded 3586** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3587** and sqlite3_prepare_v3() 3588** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3589** and sqlite3_prepare16_v3() use UTF-16. 3590** 3591** ^If the nByte argument is negative, then zSql is read up to the 3592** first zero terminator. ^If nByte is positive, then it is the 3593** number of bytes read from zSql. ^If nByte is zero, then no prepared 3594** statement is generated. 3595** If the caller knows that the supplied string is nul-terminated, then 3596** there is a small performance advantage to passing an nByte parameter that 3597** is the number of bytes in the input string <i>including</i> 3598** the nul-terminator. 3599** 3600** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3601** past the end of the first SQL statement in zSql. These routines only 3602** compile the first statement in zSql, so *pzTail is left pointing to 3603** what remains uncompiled. 3604** 3605** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3606** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3607** to NULL. ^If the input text contains no SQL (if the input is an empty 3608** string or a comment) then *ppStmt is set to NULL. 3609** The calling procedure is responsible for deleting the compiled 3610** SQL statement using [sqlite3_finalize()] after it has finished with it. 3611** ppStmt may not be NULL. 3612** 3613** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3614** otherwise an [error code] is returned. 3615** 3616** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3617** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3618** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3619** are retained for backwards compatibility, but their use is discouraged. 3620** ^In the "vX" interfaces, the prepared statement 3621** that is returned (the [sqlite3_stmt] object) contains a copy of the 3622** original SQL text. This causes the [sqlite3_step()] interface to 3623** behave differently in three ways: 3624** 3625** <ol> 3626** <li> 3627** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3628** always used to do, [sqlite3_step()] will automatically recompile the SQL 3629** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3630** retries will occur before sqlite3_step() gives up and returns an error. 3631** </li> 3632** 3633** <li> 3634** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3635** [error codes] or [extended error codes]. ^The legacy behavior was that 3636** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3637** and the application would have to make a second call to [sqlite3_reset()] 3638** in order to find the underlying cause of the problem. With the "v2" prepare 3639** interfaces, the underlying reason for the error is returned immediately. 3640** </li> 3641** 3642** <li> 3643** ^If the specific value bound to [parameter | host parameter] in the 3644** WHERE clause might influence the choice of query plan for a statement, 3645** then the statement will be automatically recompiled, as if there had been 3646** a schema change, on the first [sqlite3_step()] call following any change 3647** to the [sqlite3_bind_text | bindings] of that [parameter]. 3648** ^The specific value of WHERE-clause [parameter] might influence the 3649** choice of query plan if the parameter is the left-hand side of a [LIKE] 3650** or [GLOB] operator or if the parameter is compared to an indexed column 3651** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3652** </li> 3653** 3654** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3655** the extra prepFlags parameter, which is a bit array consisting of zero or 3656** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3657** sqlite3_prepare_v2() interface works exactly the same as 3658** sqlite3_prepare_v3() with a zero prepFlags parameter. 3659** </ol> 3660*/ 3661int sqlite3_prepare( 3662 sqlite3 *db, /* Database handle */ 3663 const char *zSql, /* SQL statement, UTF-8 encoded */ 3664 int nByte, /* Maximum length of zSql in bytes. */ 3665 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3666 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3667); 3668int sqlite3_prepare_v2( 3669 sqlite3 *db, /* Database handle */ 3670 const char *zSql, /* SQL statement, UTF-8 encoded */ 3671 int nByte, /* Maximum length of zSql in bytes. */ 3672 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3673 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3674); 3675int sqlite3_prepare_v3( 3676 sqlite3 *db, /* Database handle */ 3677 const char *zSql, /* SQL statement, UTF-8 encoded */ 3678 int nByte, /* Maximum length of zSql in bytes. */ 3679 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3680 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3681 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3682); 3683int sqlite3_prepare16( 3684 sqlite3 *db, /* Database handle */ 3685 const void *zSql, /* SQL statement, UTF-16 encoded */ 3686 int nByte, /* Maximum length of zSql in bytes. */ 3687 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3688 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3689); 3690int sqlite3_prepare16_v2( 3691 sqlite3 *db, /* Database handle */ 3692 const void *zSql, /* SQL statement, UTF-16 encoded */ 3693 int nByte, /* Maximum length of zSql in bytes. */ 3694 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3695 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3696); 3697int sqlite3_prepare16_v3( 3698 sqlite3 *db, /* Database handle */ 3699 const void *zSql, /* SQL statement, UTF-16 encoded */ 3700 int nByte, /* Maximum length of zSql in bytes. */ 3701 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3702 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3703 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3704); 3705 3706/* 3707** CAPI3REF: Retrieving Statement SQL 3708** METHOD: sqlite3_stmt 3709** 3710** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3711** SQL text used to create [prepared statement] P if P was 3712** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3713** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3714** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3715** string containing the SQL text of prepared statement P with 3716** [bound parameters] expanded. 3717** 3718** ^(For example, if a prepared statement is created using the SQL 3719** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3720** and parameter :xyz is unbound, then sqlite3_sql() will return 3721** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3722** will return "SELECT 2345,NULL".)^ 3723** 3724** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3725** is available to hold the result, or if the result would exceed the 3726** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3727** 3728** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3729** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3730** option causes sqlite3_expanded_sql() to always return NULL. 3731** 3732** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3733** automatically freed when the prepared statement is finalized. 3734** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3735** is obtained from [sqlite3_malloc()] and must be free by the application 3736** by passing it to [sqlite3_free()]. 3737*/ 3738const char *sqlite3_sql(sqlite3_stmt *pStmt); 3739char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3740 3741/* 3742** CAPI3REF: Determine If An SQL Statement Writes The Database 3743** METHOD: sqlite3_stmt 3744** 3745** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3746** and only if the [prepared statement] X makes no direct changes to 3747** the content of the database file. 3748** 3749** Note that [application-defined SQL functions] or 3750** [virtual tables] might change the database indirectly as a side effect. 3751** ^(For example, if an application defines a function "eval()" that 3752** calls [sqlite3_exec()], then the following SQL statement would 3753** change the database file through side-effects: 3754** 3755** <blockquote><pre> 3756** SELECT eval('DELETE FROM t1') FROM t2; 3757** </pre></blockquote> 3758** 3759** But because the [SELECT] statement does not change the database file 3760** directly, sqlite3_stmt_readonly() would still return true.)^ 3761** 3762** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3763** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3764** since the statements themselves do not actually modify the database but 3765** rather they control the timing of when other statements modify the 3766** database. ^The [ATTACH] and [DETACH] statements also cause 3767** sqlite3_stmt_readonly() to return true since, while those statements 3768** change the configuration of a database connection, they do not make 3769** changes to the content of the database files on disk. 3770** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3771** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3772** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3773** sqlite3_stmt_readonly() returns false for those commands. 3774*/ 3775int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3776 3777/* 3778** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3779** METHOD: sqlite3_stmt 3780** 3781** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3782** [prepared statement] S has been stepped at least once using 3783** [sqlite3_step(S)] but has neither run to completion (returned 3784** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3785** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3786** interface returns false if S is a NULL pointer. If S is not a 3787** NULL pointer and is not a pointer to a valid [prepared statement] 3788** object, then the behavior is undefined and probably undesirable. 3789** 3790** This interface can be used in combination [sqlite3_next_stmt()] 3791** to locate all prepared statements associated with a database 3792** connection that are in need of being reset. This can be used, 3793** for example, in diagnostic routines to search for prepared 3794** statements that are holding a transaction open. 3795*/ 3796int sqlite3_stmt_busy(sqlite3_stmt*); 3797 3798/* 3799** CAPI3REF: Dynamically Typed Value Object 3800** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3801** 3802** SQLite uses the sqlite3_value object to represent all values 3803** that can be stored in a database table. SQLite uses dynamic typing 3804** for the values it stores. ^Values stored in sqlite3_value objects 3805** can be integers, floating point values, strings, BLOBs, or NULL. 3806** 3807** An sqlite3_value object may be either "protected" or "unprotected". 3808** Some interfaces require a protected sqlite3_value. Other interfaces 3809** will accept either a protected or an unprotected sqlite3_value. 3810** Every interface that accepts sqlite3_value arguments specifies 3811** whether or not it requires a protected sqlite3_value. The 3812** [sqlite3_value_dup()] interface can be used to construct a new 3813** protected sqlite3_value from an unprotected sqlite3_value. 3814** 3815** The terms "protected" and "unprotected" refer to whether or not 3816** a mutex is held. An internal mutex is held for a protected 3817** sqlite3_value object but no mutex is held for an unprotected 3818** sqlite3_value object. If SQLite is compiled to be single-threaded 3819** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3820** or if SQLite is run in one of reduced mutex modes 3821** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3822** then there is no distinction between protected and unprotected 3823** sqlite3_value objects and they can be used interchangeably. However, 3824** for maximum code portability it is recommended that applications 3825** still make the distinction between protected and unprotected 3826** sqlite3_value objects even when not strictly required. 3827** 3828** ^The sqlite3_value objects that are passed as parameters into the 3829** implementation of [application-defined SQL functions] are protected. 3830** ^The sqlite3_value object returned by 3831** [sqlite3_column_value()] is unprotected. 3832** Unprotected sqlite3_value objects may only be used as arguments 3833** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3834** [sqlite3_value_dup()]. 3835** The [sqlite3_value_blob | sqlite3_value_type()] family of 3836** interfaces require protected sqlite3_value objects. 3837*/ 3838typedef struct sqlite3_value sqlite3_value; 3839 3840/* 3841** CAPI3REF: SQL Function Context Object 3842** 3843** The context in which an SQL function executes is stored in an 3844** sqlite3_context object. ^A pointer to an sqlite3_context object 3845** is always first parameter to [application-defined SQL functions]. 3846** The application-defined SQL function implementation will pass this 3847** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3848** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3849** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3850** and/or [sqlite3_set_auxdata()]. 3851*/ 3852typedef struct sqlite3_context sqlite3_context; 3853 3854/* 3855** CAPI3REF: Binding Values To Prepared Statements 3856** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3857** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3858** METHOD: sqlite3_stmt 3859** 3860** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3861** literals may be replaced by a [parameter] that matches one of following 3862** templates: 3863** 3864** <ul> 3865** <li> ? 3866** <li> ?NNN 3867** <li> :VVV 3868** <li> @VVV 3869** <li> $VVV 3870** </ul> 3871** 3872** In the templates above, NNN represents an integer literal, 3873** and VVV represents an alphanumeric identifier.)^ ^The values of these 3874** parameters (also called "host parameter names" or "SQL parameters") 3875** can be set using the sqlite3_bind_*() routines defined here. 3876** 3877** ^The first argument to the sqlite3_bind_*() routines is always 3878** a pointer to the [sqlite3_stmt] object returned from 3879** [sqlite3_prepare_v2()] or its variants. 3880** 3881** ^The second argument is the index of the SQL parameter to be set. 3882** ^The leftmost SQL parameter has an index of 1. ^When the same named 3883** SQL parameter is used more than once, second and subsequent 3884** occurrences have the same index as the first occurrence. 3885** ^The index for named parameters can be looked up using the 3886** [sqlite3_bind_parameter_index()] API if desired. ^The index 3887** for "?NNN" parameters is the value of NNN. 3888** ^The NNN value must be between 1 and the [sqlite3_limit()] 3889** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3890** 3891** ^The third argument is the value to bind to the parameter. 3892** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3893** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3894** is ignored and the end result is the same as sqlite3_bind_null(). 3895** 3896** ^(In those routines that have a fourth argument, its value is the 3897** number of bytes in the parameter. To be clear: the value is the 3898** number of <u>bytes</u> in the value, not the number of characters.)^ 3899** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3900** is negative, then the length of the string is 3901** the number of bytes up to the first zero terminator. 3902** If the fourth parameter to sqlite3_bind_blob() is negative, then 3903** the behavior is undefined. 3904** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3905** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3906** that parameter must be the byte offset 3907** where the NUL terminator would occur assuming the string were NUL 3908** terminated. If any NUL characters occur at byte offsets less than 3909** the value of the fourth parameter then the resulting string value will 3910** contain embedded NULs. The result of expressions involving strings 3911** with embedded NULs is undefined. 3912** 3913** ^The fifth argument to the BLOB and string binding interfaces 3914** is a destructor used to dispose of the BLOB or 3915** string after SQLite has finished with it. ^The destructor is called 3916** to dispose of the BLOB or string even if the call to bind API fails. 3917** ^If the fifth argument is 3918** the special value [SQLITE_STATIC], then SQLite assumes that the 3919** information is in static, unmanaged space and does not need to be freed. 3920** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3921** SQLite makes its own private copy of the data immediately, before 3922** the sqlite3_bind_*() routine returns. 3923** 3924** ^The sixth argument to sqlite3_bind_text64() must be one of 3925** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3926** to specify the encoding of the text in the third parameter. If 3927** the sixth argument to sqlite3_bind_text64() is not one of the 3928** allowed values shown above, or if the text encoding is different 3929** from the encoding specified by the sixth parameter, then the behavior 3930** is undefined. 3931** 3932** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3933** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3934** (just an integer to hold its size) while it is being processed. 3935** Zeroblobs are intended to serve as placeholders for BLOBs whose 3936** content is later written using 3937** [sqlite3_blob_open | incremental BLOB I/O] routines. 3938** ^A negative value for the zeroblob results in a zero-length BLOB. 3939** 3940** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3941** [prepared statement] S to have an SQL value of NULL, but to also be 3942** associated with the pointer P of type T. ^D is either a NULL pointer or 3943** a pointer to a destructor function for P. ^SQLite will invoke the 3944** destructor D with a single argument of P when it is finished using 3945** P. The T parameter should be a static string, preferably a string 3946** literal. The sqlite3_bind_pointer() routine is part of the 3947** [pointer passing interface] added for SQLite 3.20.0. 3948** 3949** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3950** for the [prepared statement] or with a prepared statement for which 3951** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3952** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3953** routine is passed a [prepared statement] that has been finalized, the 3954** result is undefined and probably harmful. 3955** 3956** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3957** ^Unbound parameters are interpreted as NULL. 3958** 3959** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3960** [error code] if anything goes wrong. 3961** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3962** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3963** [SQLITE_MAX_LENGTH]. 3964** ^[SQLITE_RANGE] is returned if the parameter 3965** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3966** 3967** See also: [sqlite3_bind_parameter_count()], 3968** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3969*/ 3970int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3971int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3972 void(*)(void*)); 3973int sqlite3_bind_double(sqlite3_stmt*, int, double); 3974int sqlite3_bind_int(sqlite3_stmt*, int, int); 3975int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3976int sqlite3_bind_null(sqlite3_stmt*, int); 3977int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3978int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3979int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3980 void(*)(void*), unsigned char encoding); 3981int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3982int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3983int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3984int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3985 3986/* 3987** CAPI3REF: Number Of SQL Parameters 3988** METHOD: sqlite3_stmt 3989** 3990** ^This routine can be used to find the number of [SQL parameters] 3991** in a [prepared statement]. SQL parameters are tokens of the 3992** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3993** placeholders for values that are [sqlite3_bind_blob | bound] 3994** to the parameters at a later time. 3995** 3996** ^(This routine actually returns the index of the largest (rightmost) 3997** parameter. For all forms except ?NNN, this will correspond to the 3998** number of unique parameters. If parameters of the ?NNN form are used, 3999** there may be gaps in the list.)^ 4000** 4001** See also: [sqlite3_bind_blob|sqlite3_bind()], 4002** [sqlite3_bind_parameter_name()], and 4003** [sqlite3_bind_parameter_index()]. 4004*/ 4005int sqlite3_bind_parameter_count(sqlite3_stmt*); 4006 4007/* 4008** CAPI3REF: Name Of A Host Parameter 4009** METHOD: sqlite3_stmt 4010** 4011** ^The sqlite3_bind_parameter_name(P,N) interface returns 4012** the name of the N-th [SQL parameter] in the [prepared statement] P. 4013** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4014** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4015** respectively. 4016** In other words, the initial ":" or "$" or "@" or "?" 4017** is included as part of the name.)^ 4018** ^Parameters of the form "?" without a following integer have no name 4019** and are referred to as "nameless" or "anonymous parameters". 4020** 4021** ^The first host parameter has an index of 1, not 0. 4022** 4023** ^If the value N is out of range or if the N-th parameter is 4024** nameless, then NULL is returned. ^The returned string is 4025** always in UTF-8 encoding even if the named parameter was 4026** originally specified as UTF-16 in [sqlite3_prepare16()], 4027** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4028** 4029** See also: [sqlite3_bind_blob|sqlite3_bind()], 4030** [sqlite3_bind_parameter_count()], and 4031** [sqlite3_bind_parameter_index()]. 4032*/ 4033const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4034 4035/* 4036** CAPI3REF: Index Of A Parameter With A Given Name 4037** METHOD: sqlite3_stmt 4038** 4039** ^Return the index of an SQL parameter given its name. ^The 4040** index value returned is suitable for use as the second 4041** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4042** is returned if no matching parameter is found. ^The parameter 4043** name must be given in UTF-8 even if the original statement 4044** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4045** [sqlite3_prepare16_v3()]. 4046** 4047** See also: [sqlite3_bind_blob|sqlite3_bind()], 4048** [sqlite3_bind_parameter_count()], and 4049** [sqlite3_bind_parameter_name()]. 4050*/ 4051int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4052 4053/* 4054** CAPI3REF: Reset All Bindings On A Prepared Statement 4055** METHOD: sqlite3_stmt 4056** 4057** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4058** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4059** ^Use this routine to reset all host parameters to NULL. 4060*/ 4061int sqlite3_clear_bindings(sqlite3_stmt*); 4062 4063/* 4064** CAPI3REF: Number Of Columns In A Result Set 4065** METHOD: sqlite3_stmt 4066** 4067** ^Return the number of columns in the result set returned by the 4068** [prepared statement]. ^If this routine returns 0, that means the 4069** [prepared statement] returns no data (for example an [UPDATE]). 4070** ^However, just because this routine returns a positive number does not 4071** mean that one or more rows of data will be returned. ^A SELECT statement 4072** will always have a positive sqlite3_column_count() but depending on the 4073** WHERE clause constraints and the table content, it might return no rows. 4074** 4075** See also: [sqlite3_data_count()] 4076*/ 4077int sqlite3_column_count(sqlite3_stmt *pStmt); 4078 4079/* 4080** CAPI3REF: Column Names In A Result Set 4081** METHOD: sqlite3_stmt 4082** 4083** ^These routines return the name assigned to a particular column 4084** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4085** interface returns a pointer to a zero-terminated UTF-8 string 4086** and sqlite3_column_name16() returns a pointer to a zero-terminated 4087** UTF-16 string. ^The first parameter is the [prepared statement] 4088** that implements the [SELECT] statement. ^The second parameter is the 4089** column number. ^The leftmost column is number 0. 4090** 4091** ^The returned string pointer is valid until either the [prepared statement] 4092** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4093** reprepared by the first call to [sqlite3_step()] for a particular run 4094** or until the next call to 4095** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4096** 4097** ^If sqlite3_malloc() fails during the processing of either routine 4098** (for example during a conversion from UTF-8 to UTF-16) then a 4099** NULL pointer is returned. 4100** 4101** ^The name of a result column is the value of the "AS" clause for 4102** that column, if there is an AS clause. If there is no AS clause 4103** then the name of the column is unspecified and may change from 4104** one release of SQLite to the next. 4105*/ 4106const char *sqlite3_column_name(sqlite3_stmt*, int N); 4107const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4108 4109/* 4110** CAPI3REF: Source Of Data In A Query Result 4111** METHOD: sqlite3_stmt 4112** 4113** ^These routines provide a means to determine the database, table, and 4114** table column that is the origin of a particular result column in 4115** [SELECT] statement. 4116** ^The name of the database or table or column can be returned as 4117** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4118** the database name, the _table_ routines return the table name, and 4119** the origin_ routines return the column name. 4120** ^The returned string is valid until the [prepared statement] is destroyed 4121** using [sqlite3_finalize()] or until the statement is automatically 4122** reprepared by the first call to [sqlite3_step()] for a particular run 4123** or until the same information is requested 4124** again in a different encoding. 4125** 4126** ^The names returned are the original un-aliased names of the 4127** database, table, and column. 4128** 4129** ^The first argument to these interfaces is a [prepared statement]. 4130** ^These functions return information about the Nth result column returned by 4131** the statement, where N is the second function argument. 4132** ^The left-most column is column 0 for these routines. 4133** 4134** ^If the Nth column returned by the statement is an expression or 4135** subquery and is not a column value, then all of these functions return 4136** NULL. ^These routine might also return NULL if a memory allocation error 4137** occurs. ^Otherwise, they return the name of the attached database, table, 4138** or column that query result column was extracted from. 4139** 4140** ^As with all other SQLite APIs, those whose names end with "16" return 4141** UTF-16 encoded strings and the other functions return UTF-8. 4142** 4143** ^These APIs are only available if the library was compiled with the 4144** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4145** 4146** If two or more threads call one or more of these routines against the same 4147** prepared statement and column at the same time then the results are 4148** undefined. 4149** 4150** If two or more threads call one or more 4151** [sqlite3_column_database_name | column metadata interfaces] 4152** for the same [prepared statement] and result column 4153** at the same time then the results are undefined. 4154*/ 4155const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4156const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4157const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4158const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4159const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4160const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4161 4162/* 4163** CAPI3REF: Declared Datatype Of A Query Result 4164** METHOD: sqlite3_stmt 4165** 4166** ^(The first parameter is a [prepared statement]. 4167** If this statement is a [SELECT] statement and the Nth column of the 4168** returned result set of that [SELECT] is a table column (not an 4169** expression or subquery) then the declared type of the table 4170** column is returned.)^ ^If the Nth column of the result set is an 4171** expression or subquery, then a NULL pointer is returned. 4172** ^The returned string is always UTF-8 encoded. 4173** 4174** ^(For example, given the database schema: 4175** 4176** CREATE TABLE t1(c1 VARIANT); 4177** 4178** and the following statement to be compiled: 4179** 4180** SELECT c1 + 1, c1 FROM t1; 4181** 4182** this routine would return the string "VARIANT" for the second result 4183** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4184** 4185** ^SQLite uses dynamic run-time typing. ^So just because a column 4186** is declared to contain a particular type does not mean that the 4187** data stored in that column is of the declared type. SQLite is 4188** strongly typed, but the typing is dynamic not static. ^Type 4189** is associated with individual values, not with the containers 4190** used to hold those values. 4191*/ 4192const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4193const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4194 4195/* 4196** CAPI3REF: Evaluate An SQL Statement 4197** METHOD: sqlite3_stmt 4198** 4199** After a [prepared statement] has been prepared using any of 4200** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4201** or [sqlite3_prepare16_v3()] or one of the legacy 4202** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4203** must be called one or more times to evaluate the statement. 4204** 4205** The details of the behavior of the sqlite3_step() interface depend 4206** on whether the statement was prepared using the newer "vX" interfaces 4207** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4208** [sqlite3_prepare16_v2()] or the older legacy 4209** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4210** new "vX" interface is recommended for new applications but the legacy 4211** interface will continue to be supported. 4212** 4213** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4214** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4215** ^With the "v2" interface, any of the other [result codes] or 4216** [extended result codes] might be returned as well. 4217** 4218** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4219** database locks it needs to do its job. ^If the statement is a [COMMIT] 4220** or occurs outside of an explicit transaction, then you can retry the 4221** statement. If the statement is not a [COMMIT] and occurs within an 4222** explicit transaction then you should rollback the transaction before 4223** continuing. 4224** 4225** ^[SQLITE_DONE] means that the statement has finished executing 4226** successfully. sqlite3_step() should not be called again on this virtual 4227** machine without first calling [sqlite3_reset()] to reset the virtual 4228** machine back to its initial state. 4229** 4230** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4231** is returned each time a new row of data is ready for processing by the 4232** caller. The values may be accessed using the [column access functions]. 4233** sqlite3_step() is called again to retrieve the next row of data. 4234** 4235** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4236** violation) has occurred. sqlite3_step() should not be called again on 4237** the VM. More information may be found by calling [sqlite3_errmsg()]. 4238** ^With the legacy interface, a more specific error code (for example, 4239** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4240** can be obtained by calling [sqlite3_reset()] on the 4241** [prepared statement]. ^In the "v2" interface, 4242** the more specific error code is returned directly by sqlite3_step(). 4243** 4244** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4245** Perhaps it was called on a [prepared statement] that has 4246** already been [sqlite3_finalize | finalized] or on one that had 4247** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4248** be the case that the same database connection is being used by two or 4249** more threads at the same moment in time. 4250** 4251** For all versions of SQLite up to and including 3.6.23.1, a call to 4252** [sqlite3_reset()] was required after sqlite3_step() returned anything 4253** other than [SQLITE_ROW] before any subsequent invocation of 4254** sqlite3_step(). Failure to reset the prepared statement using 4255** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4256** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4257** sqlite3_step() began 4258** calling [sqlite3_reset()] automatically in this circumstance rather 4259** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4260** break because any application that ever receives an SQLITE_MISUSE error 4261** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4262** can be used to restore the legacy behavior. 4263** 4264** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4265** API always returns a generic error code, [SQLITE_ERROR], following any 4266** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4267** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4268** specific [error codes] that better describes the error. 4269** We admit that this is a goofy design. The problem has been fixed 4270** with the "v2" interface. If you prepare all of your SQL statements 4271** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4272** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4273** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4274** then the more specific [error codes] are returned directly 4275** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4276*/ 4277int sqlite3_step(sqlite3_stmt*); 4278 4279/* 4280** CAPI3REF: Number of columns in a result set 4281** METHOD: sqlite3_stmt 4282** 4283** ^The sqlite3_data_count(P) interface returns the number of columns in the 4284** current row of the result set of [prepared statement] P. 4285** ^If prepared statement P does not have results ready to return 4286** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4287** interfaces) then sqlite3_data_count(P) returns 0. 4288** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4289** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4290** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4291** will return non-zero if previous call to [sqlite3_step](P) returned 4292** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4293** where it always returns zero since each step of that multi-step 4294** pragma returns 0 columns of data. 4295** 4296** See also: [sqlite3_column_count()] 4297*/ 4298int sqlite3_data_count(sqlite3_stmt *pStmt); 4299 4300/* 4301** CAPI3REF: Fundamental Datatypes 4302** KEYWORDS: SQLITE_TEXT 4303** 4304** ^(Every value in SQLite has one of five fundamental datatypes: 4305** 4306** <ul> 4307** <li> 64-bit signed integer 4308** <li> 64-bit IEEE floating point number 4309** <li> string 4310** <li> BLOB 4311** <li> NULL 4312** </ul>)^ 4313** 4314** These constants are codes for each of those types. 4315** 4316** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4317** for a completely different meaning. Software that links against both 4318** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4319** SQLITE_TEXT. 4320*/ 4321#define SQLITE_INTEGER 1 4322#define SQLITE_FLOAT 2 4323#define SQLITE_BLOB 4 4324#define SQLITE_NULL 5 4325#ifdef SQLITE_TEXT 4326# undef SQLITE_TEXT 4327#else 4328# define SQLITE_TEXT 3 4329#endif 4330#define SQLITE3_TEXT 3 4331 4332/* 4333** CAPI3REF: Result Values From A Query 4334** KEYWORDS: {column access functions} 4335** METHOD: sqlite3_stmt 4336** 4337** <b>Summary:</b> 4338** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4339** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4340** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4341** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4342** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4343** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4344** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4345** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4346** [sqlite3_value|unprotected sqlite3_value] object. 4347** <tr><td> <td> <td> 4348** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4349** or a UTF-8 TEXT result in bytes 4350** <tr><td><b>sqlite3_column_bytes16 </b> 4351** <td>→ <td>Size of UTF-16 4352** TEXT in bytes 4353** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4354** datatype of the result 4355** </table></blockquote> 4356** 4357** <b>Details:</b> 4358** 4359** ^These routines return information about a single column of the current 4360** result row of a query. ^In every case the first argument is a pointer 4361** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4362** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4363** and the second argument is the index of the column for which information 4364** should be returned. ^The leftmost column of the result set has the index 0. 4365** ^The number of columns in the result can be determined using 4366** [sqlite3_column_count()]. 4367** 4368** If the SQL statement does not currently point to a valid row, or if the 4369** column index is out of range, the result is undefined. 4370** These routines may only be called when the most recent call to 4371** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4372** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4373** If any of these routines are called after [sqlite3_reset()] or 4374** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4375** something other than [SQLITE_ROW], the results are undefined. 4376** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4377** are called from a different thread while any of these routines 4378** are pending, then the results are undefined. 4379** 4380** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4381** each return the value of a result column in a specific data format. If 4382** the result column is not initially in the requested format (for example, 4383** if the query returns an integer but the sqlite3_column_text() interface 4384** is used to extract the value) then an automatic type conversion is performed. 4385** 4386** ^The sqlite3_column_type() routine returns the 4387** [SQLITE_INTEGER | datatype code] for the initial data type 4388** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4389** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4390** The return value of sqlite3_column_type() can be used to decide which 4391** of the first six interface should be used to extract the column value. 4392** The value returned by sqlite3_column_type() is only meaningful if no 4393** automatic type conversions have occurred for the value in question. 4394** After a type conversion, the result of calling sqlite3_column_type() 4395** is undefined, though harmless. Future 4396** versions of SQLite may change the behavior of sqlite3_column_type() 4397** following a type conversion. 4398** 4399** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4400** or sqlite3_column_bytes16() interfaces can be used to determine the size 4401** of that BLOB or string. 4402** 4403** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4404** routine returns the number of bytes in that BLOB or string. 4405** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4406** the string to UTF-8 and then returns the number of bytes. 4407** ^If the result is a numeric value then sqlite3_column_bytes() uses 4408** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4409** the number of bytes in that string. 4410** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4411** 4412** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4413** routine returns the number of bytes in that BLOB or string. 4414** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4415** the string to UTF-16 and then returns the number of bytes. 4416** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4417** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4418** the number of bytes in that string. 4419** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4420** 4421** ^The values returned by [sqlite3_column_bytes()] and 4422** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4423** of the string. ^For clarity: the values returned by 4424** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4425** bytes in the string, not the number of characters. 4426** 4427** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4428** even empty strings, are always zero-terminated. ^The return 4429** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4430** 4431** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4432** [unprotected sqlite3_value] object. In a multithreaded environment, 4433** an unprotected sqlite3_value object may only be used safely with 4434** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4435** If the [unprotected sqlite3_value] object returned by 4436** [sqlite3_column_value()] is used in any other way, including calls 4437** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4438** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4439** Hence, the sqlite3_column_value() interface 4440** is normally only useful within the implementation of 4441** [application-defined SQL functions] or [virtual tables], not within 4442** top-level application code. 4443** 4444** The these routines may attempt to convert the datatype of the result. 4445** ^For example, if the internal representation is FLOAT and a text result 4446** is requested, [sqlite3_snprintf()] is used internally to perform the 4447** conversion automatically. ^(The following table details the conversions 4448** that are applied: 4449** 4450** <blockquote> 4451** <table border="1"> 4452** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4453** 4454** <tr><td> NULL <td> INTEGER <td> Result is 0 4455** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4456** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4457** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4458** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4459** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4460** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4461** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4462** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4463** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4464** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4465** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4466** <tr><td> TEXT <td> BLOB <td> No change 4467** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4468** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4469** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4470** </table> 4471** </blockquote>)^ 4472** 4473** Note that when type conversions occur, pointers returned by prior 4474** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4475** sqlite3_column_text16() may be invalidated. 4476** Type conversions and pointer invalidations might occur 4477** in the following cases: 4478** 4479** <ul> 4480** <li> The initial content is a BLOB and sqlite3_column_text() or 4481** sqlite3_column_text16() is called. A zero-terminator might 4482** need to be added to the string.</li> 4483** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4484** sqlite3_column_text16() is called. The content must be converted 4485** to UTF-16.</li> 4486** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4487** sqlite3_column_text() is called. The content must be converted 4488** to UTF-8.</li> 4489** </ul> 4490** 4491** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4492** not invalidate a prior pointer, though of course the content of the buffer 4493** that the prior pointer references will have been modified. Other kinds 4494** of conversion are done in place when it is possible, but sometimes they 4495** are not possible and in those cases prior pointers are invalidated. 4496** 4497** The safest policy is to invoke these routines 4498** in one of the following ways: 4499** 4500** <ul> 4501** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4502** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4503** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4504** </ul> 4505** 4506** In other words, you should call sqlite3_column_text(), 4507** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4508** into the desired format, then invoke sqlite3_column_bytes() or 4509** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4510** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4511** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4512** with calls to sqlite3_column_bytes(). 4513** 4514** ^The pointers returned are valid until a type conversion occurs as 4515** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4516** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4517** and BLOBs is freed automatically. Do not pass the pointers returned 4518** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4519** [sqlite3_free()]. 4520** 4521** ^(If a memory allocation error occurs during the evaluation of any 4522** of these routines, a default value is returned. The default value 4523** is either the integer 0, the floating point number 0.0, or a NULL 4524** pointer. Subsequent calls to [sqlite3_errcode()] will return 4525** [SQLITE_NOMEM].)^ 4526*/ 4527const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4528double sqlite3_column_double(sqlite3_stmt*, int iCol); 4529int sqlite3_column_int(sqlite3_stmt*, int iCol); 4530sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4531const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4532const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4533sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4534int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4535int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4536int sqlite3_column_type(sqlite3_stmt*, int iCol); 4537 4538/* 4539** CAPI3REF: Destroy A Prepared Statement Object 4540** DESTRUCTOR: sqlite3_stmt 4541** 4542** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4543** ^If the most recent evaluation of the statement encountered no errors 4544** or if the statement is never been evaluated, then sqlite3_finalize() returns 4545** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4546** sqlite3_finalize(S) returns the appropriate [error code] or 4547** [extended error code]. 4548** 4549** ^The sqlite3_finalize(S) routine can be called at any point during 4550** the life cycle of [prepared statement] S: 4551** before statement S is ever evaluated, after 4552** one or more calls to [sqlite3_reset()], or after any call 4553** to [sqlite3_step()] regardless of whether or not the statement has 4554** completed execution. 4555** 4556** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4557** 4558** The application must finalize every [prepared statement] in order to avoid 4559** resource leaks. It is a grievous error for the application to try to use 4560** a prepared statement after it has been finalized. Any use of a prepared 4561** statement after it has been finalized can result in undefined and 4562** undesirable behavior such as segfaults and heap corruption. 4563*/ 4564int sqlite3_finalize(sqlite3_stmt *pStmt); 4565 4566/* 4567** CAPI3REF: Reset A Prepared Statement Object 4568** METHOD: sqlite3_stmt 4569** 4570** The sqlite3_reset() function is called to reset a [prepared statement] 4571** object back to its initial state, ready to be re-executed. 4572** ^Any SQL statement variables that had values bound to them using 4573** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4574** Use [sqlite3_clear_bindings()] to reset the bindings. 4575** 4576** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4577** back to the beginning of its program. 4578** 4579** ^If the most recent call to [sqlite3_step(S)] for the 4580** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4581** or if [sqlite3_step(S)] has never before been called on S, 4582** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4583** 4584** ^If the most recent call to [sqlite3_step(S)] for the 4585** [prepared statement] S indicated an error, then 4586** [sqlite3_reset(S)] returns an appropriate [error code]. 4587** 4588** ^The [sqlite3_reset(S)] interface does not change the values 4589** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4590*/ 4591int sqlite3_reset(sqlite3_stmt *pStmt); 4592 4593/* 4594** CAPI3REF: Create Or Redefine SQL Functions 4595** KEYWORDS: {function creation routines} 4596** KEYWORDS: {application-defined SQL function} 4597** KEYWORDS: {application-defined SQL functions} 4598** METHOD: sqlite3 4599** 4600** ^These functions (collectively known as "function creation routines") 4601** are used to add SQL functions or aggregates or to redefine the behavior 4602** of existing SQL functions or aggregates. The only differences between 4603** these routines are the text encoding expected for 4604** the second parameter (the name of the function being created) 4605** and the presence or absence of a destructor callback for 4606** the application data pointer. 4607** 4608** ^The first parameter is the [database connection] to which the SQL 4609** function is to be added. ^If an application uses more than one database 4610** connection then application-defined SQL functions must be added 4611** to each database connection separately. 4612** 4613** ^The second parameter is the name of the SQL function to be created or 4614** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4615** representation, exclusive of the zero-terminator. ^Note that the name 4616** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4617** ^Any attempt to create a function with a longer name 4618** will result in [SQLITE_MISUSE] being returned. 4619** 4620** ^The third parameter (nArg) 4621** is the number of arguments that the SQL function or 4622** aggregate takes. ^If this parameter is -1, then the SQL function or 4623** aggregate may take any number of arguments between 0 and the limit 4624** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4625** parameter is less than -1 or greater than 127 then the behavior is 4626** undefined. 4627** 4628** ^The fourth parameter, eTextRep, specifies what 4629** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4630** its parameters. The application should set this parameter to 4631** [SQLITE_UTF16LE] if the function implementation invokes 4632** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4633** implementation invokes [sqlite3_value_text16be()] on an input, or 4634** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4635** otherwise. ^The same SQL function may be registered multiple times using 4636** different preferred text encodings, with different implementations for 4637** each encoding. 4638** ^When multiple implementations of the same function are available, SQLite 4639** will pick the one that involves the least amount of data conversion. 4640** 4641** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4642** to signal that the function will always return the same result given 4643** the same inputs within a single SQL statement. Most SQL functions are 4644** deterministic. The built-in [random()] SQL function is an example of a 4645** function that is not deterministic. The SQLite query planner is able to 4646** perform additional optimizations on deterministic functions, so use 4647** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4648** 4649** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4650** function can gain access to this pointer using [sqlite3_user_data()].)^ 4651** 4652** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4653** pointers to C-language functions that implement the SQL function or 4654** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4655** callback only; NULL pointers must be passed as the xStep and xFinal 4656** parameters. ^An aggregate SQL function requires an implementation of xStep 4657** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4658** SQL function or aggregate, pass NULL pointers for all three function 4659** callbacks. 4660** 4661** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4662** then it is destructor for the application data pointer. 4663** The destructor is invoked when the function is deleted, either by being 4664** overloaded or when the database connection closes.)^ 4665** ^The destructor is also invoked if the call to 4666** sqlite3_create_function_v2() fails. 4667** ^When the destructor callback of the tenth parameter is invoked, it 4668** is passed a single argument which is a copy of the application data 4669** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4670** 4671** ^It is permitted to register multiple implementations of the same 4672** functions with the same name but with either differing numbers of 4673** arguments or differing preferred text encodings. ^SQLite will use 4674** the implementation that most closely matches the way in which the 4675** SQL function is used. ^A function implementation with a non-negative 4676** nArg parameter is a better match than a function implementation with 4677** a negative nArg. ^A function where the preferred text encoding 4678** matches the database encoding is a better 4679** match than a function where the encoding is different. 4680** ^A function where the encoding difference is between UTF16le and UTF16be 4681** is a closer match than a function where the encoding difference is 4682** between UTF8 and UTF16. 4683** 4684** ^Built-in functions may be overloaded by new application-defined functions. 4685** 4686** ^An application-defined function is permitted to call other 4687** SQLite interfaces. However, such calls must not 4688** close the database connection nor finalize or reset the prepared 4689** statement in which the function is running. 4690*/ 4691int sqlite3_create_function( 4692 sqlite3 *db, 4693 const char *zFunctionName, 4694 int nArg, 4695 int eTextRep, 4696 void *pApp, 4697 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4698 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4699 void (*xFinal)(sqlite3_context*) 4700); 4701int sqlite3_create_function16( 4702 sqlite3 *db, 4703 const void *zFunctionName, 4704 int nArg, 4705 int eTextRep, 4706 void *pApp, 4707 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4708 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4709 void (*xFinal)(sqlite3_context*) 4710); 4711int sqlite3_create_function_v2( 4712 sqlite3 *db, 4713 const char *zFunctionName, 4714 int nArg, 4715 int eTextRep, 4716 void *pApp, 4717 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4718 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4719 void (*xFinal)(sqlite3_context*), 4720 void(*xDestroy)(void*) 4721); 4722 4723/* 4724** CAPI3REF: Text Encodings 4725** 4726** These constant define integer codes that represent the various 4727** text encodings supported by SQLite. 4728*/ 4729#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4730#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4731#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4732#define SQLITE_UTF16 4 /* Use native byte order */ 4733#define SQLITE_ANY 5 /* Deprecated */ 4734#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4735 4736/* 4737** CAPI3REF: Function Flags 4738** 4739** These constants may be ORed together with the 4740** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4741** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4742** [sqlite3_create_function_v2()]. 4743*/ 4744#define SQLITE_DETERMINISTIC 0x800 4745 4746/* 4747** CAPI3REF: Deprecated Functions 4748** DEPRECATED 4749** 4750** These functions are [deprecated]. In order to maintain 4751** backwards compatibility with older code, these functions continue 4752** to be supported. However, new applications should avoid 4753** the use of these functions. To encourage programmers to avoid 4754** these functions, we will not explain what they do. 4755*/ 4756#ifndef SQLITE_OMIT_DEPRECATED 4757SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4758SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4759SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4760SQLITE_DEPRECATED int sqlite3_global_recover(void); 4761SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4762SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4763 void*,sqlite3_int64); 4764#endif 4765 4766/* 4767** CAPI3REF: Obtaining SQL Values 4768** METHOD: sqlite3_value 4769** 4770** <b>Summary:</b> 4771** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4772** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4773** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4774** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4775** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4776** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4777** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4778** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4779** the native byteorder 4780** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4781** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4782** <tr><td> <td> <td> 4783** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4784** or a UTF-8 TEXT in bytes 4785** <tr><td><b>sqlite3_value_bytes16 </b> 4786** <td>→ <td>Size of UTF-16 4787** TEXT in bytes 4788** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4789** datatype of the value 4790** <tr><td><b>sqlite3_value_numeric_type </b> 4791** <td>→ <td>Best numeric datatype of the value 4792** </table></blockquote> 4793** 4794** <b>Details:</b> 4795** 4796** These routines extract type, size, and content information from 4797** [protected sqlite3_value] objects. Protected sqlite3_value objects 4798** are used to pass parameter information into implementation of 4799** [application-defined SQL functions] and [virtual tables]. 4800** 4801** These routines work only with [protected sqlite3_value] objects. 4802** Any attempt to use these routines on an [unprotected sqlite3_value] 4803** is not threadsafe. 4804** 4805** ^These routines work just like the corresponding [column access functions] 4806** except that these routines take a single [protected sqlite3_value] object 4807** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4808** 4809** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4810** in the native byte-order of the host machine. ^The 4811** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4812** extract UTF-16 strings as big-endian and little-endian respectively. 4813** 4814** ^If [sqlite3_value] object V was initialized 4815** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4816** and if X and Y are strings that compare equal according to strcmp(X,Y), 4817** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4818** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4819** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4820** 4821** ^(The sqlite3_value_type(V) interface returns the 4822** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4823** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4824** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4825** Other interfaces might change the datatype for an sqlite3_value object. 4826** For example, if the datatype is initially SQLITE_INTEGER and 4827** sqlite3_value_text(V) is called to extract a text value for that 4828** integer, then subsequent calls to sqlite3_value_type(V) might return 4829** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4830** occurs is undefined and may change from one release of SQLite to the next. 4831** 4832** ^(The sqlite3_value_numeric_type() interface attempts to apply 4833** numeric affinity to the value. This means that an attempt is 4834** made to convert the value to an integer or floating point. If 4835** such a conversion is possible without loss of information (in other 4836** words, if the value is a string that looks like a number) 4837** then the conversion is performed. Otherwise no conversion occurs. 4838** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4839** 4840** Please pay particular attention to the fact that the pointer returned 4841** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4842** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4843** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4844** or [sqlite3_value_text16()]. 4845** 4846** These routines must be called from the same thread as 4847** the SQL function that supplied the [sqlite3_value*] parameters. 4848*/ 4849const void *sqlite3_value_blob(sqlite3_value*); 4850double sqlite3_value_double(sqlite3_value*); 4851int sqlite3_value_int(sqlite3_value*); 4852sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4853void *sqlite3_value_pointer(sqlite3_value*, const char*); 4854const unsigned char *sqlite3_value_text(sqlite3_value*); 4855const void *sqlite3_value_text16(sqlite3_value*); 4856const void *sqlite3_value_text16le(sqlite3_value*); 4857const void *sqlite3_value_text16be(sqlite3_value*); 4858int sqlite3_value_bytes(sqlite3_value*); 4859int sqlite3_value_bytes16(sqlite3_value*); 4860int sqlite3_value_type(sqlite3_value*); 4861int sqlite3_value_numeric_type(sqlite3_value*); 4862 4863/* 4864** CAPI3REF: Finding The Subtype Of SQL Values 4865** METHOD: sqlite3_value 4866** 4867** The sqlite3_value_subtype(V) function returns the subtype for 4868** an [application-defined SQL function] argument V. The subtype 4869** information can be used to pass a limited amount of context from 4870** one SQL function to another. Use the [sqlite3_result_subtype()] 4871** routine to set the subtype for the return value of an SQL function. 4872*/ 4873unsigned int sqlite3_value_subtype(sqlite3_value*); 4874 4875/* 4876** CAPI3REF: Copy And Free SQL Values 4877** METHOD: sqlite3_value 4878** 4879** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4880** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4881** is a [protected sqlite3_value] object even if the input is not. 4882** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4883** memory allocation fails. 4884** 4885** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4886** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4887** then sqlite3_value_free(V) is a harmless no-op. 4888*/ 4889sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4890void sqlite3_value_free(sqlite3_value*); 4891 4892/* 4893** CAPI3REF: Obtain Aggregate Function Context 4894** METHOD: sqlite3_context 4895** 4896** Implementations of aggregate SQL functions use this 4897** routine to allocate memory for storing their state. 4898** 4899** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4900** for a particular aggregate function, SQLite 4901** allocates N of memory, zeroes out that memory, and returns a pointer 4902** to the new memory. ^On second and subsequent calls to 4903** sqlite3_aggregate_context() for the same aggregate function instance, 4904** the same buffer is returned. Sqlite3_aggregate_context() is normally 4905** called once for each invocation of the xStep callback and then one 4906** last time when the xFinal callback is invoked. ^(When no rows match 4907** an aggregate query, the xStep() callback of the aggregate function 4908** implementation is never called and xFinal() is called exactly once. 4909** In those cases, sqlite3_aggregate_context() might be called for the 4910** first time from within xFinal().)^ 4911** 4912** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4913** when first called if N is less than or equal to zero or if a memory 4914** allocate error occurs. 4915** 4916** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4917** determined by the N parameter on first successful call. Changing the 4918** value of N in subsequent call to sqlite3_aggregate_context() within 4919** the same aggregate function instance will not resize the memory 4920** allocation.)^ Within the xFinal callback, it is customary to set 4921** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4922** pointless memory allocations occur. 4923** 4924** ^SQLite automatically frees the memory allocated by 4925** sqlite3_aggregate_context() when the aggregate query concludes. 4926** 4927** The first parameter must be a copy of the 4928** [sqlite3_context | SQL function context] that is the first parameter 4929** to the xStep or xFinal callback routine that implements the aggregate 4930** function. 4931** 4932** This routine must be called from the same thread in which 4933** the aggregate SQL function is running. 4934*/ 4935void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4936 4937/* 4938** CAPI3REF: User Data For Functions 4939** METHOD: sqlite3_context 4940** 4941** ^The sqlite3_user_data() interface returns a copy of 4942** the pointer that was the pUserData parameter (the 5th parameter) 4943** of the [sqlite3_create_function()] 4944** and [sqlite3_create_function16()] routines that originally 4945** registered the application defined function. 4946** 4947** This routine must be called from the same thread in which 4948** the application-defined function is running. 4949*/ 4950void *sqlite3_user_data(sqlite3_context*); 4951 4952/* 4953** CAPI3REF: Database Connection For Functions 4954** METHOD: sqlite3_context 4955** 4956** ^The sqlite3_context_db_handle() interface returns a copy of 4957** the pointer to the [database connection] (the 1st parameter) 4958** of the [sqlite3_create_function()] 4959** and [sqlite3_create_function16()] routines that originally 4960** registered the application defined function. 4961*/ 4962sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4963 4964/* 4965** CAPI3REF: Function Auxiliary Data 4966** METHOD: sqlite3_context 4967** 4968** These functions may be used by (non-aggregate) SQL functions to 4969** associate metadata with argument values. If the same value is passed to 4970** multiple invocations of the same SQL function during query execution, under 4971** some circumstances the associated metadata may be preserved. An example 4972** of where this might be useful is in a regular-expression matching 4973** function. The compiled version of the regular expression can be stored as 4974** metadata associated with the pattern string. 4975** Then as long as the pattern string remains the same, 4976** the compiled regular expression can be reused on multiple 4977** invocations of the same function. 4978** 4979** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4980** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4981** value to the application-defined function. ^N is zero for the left-most 4982** function argument. ^If there is no metadata 4983** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4984** returns a NULL pointer. 4985** 4986** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4987** argument of the application-defined function. ^Subsequent 4988** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4989** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4990** NULL if the metadata has been discarded. 4991** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4992** SQLite will invoke the destructor function X with parameter P exactly 4993** once, when the metadata is discarded. 4994** SQLite is free to discard the metadata at any time, including: <ul> 4995** <li> ^(when the corresponding function parameter changes)^, or 4996** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4997** SQL statement)^, or 4998** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4999** parameter)^, or 5000** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5001** allocation error occurs.)^ </ul> 5002** 5003** Note the last bullet in particular. The destructor X in 5004** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5005** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5006** should be called near the end of the function implementation and the 5007** function implementation should not make any use of P after 5008** sqlite3_set_auxdata() has been called. 5009** 5010** ^(In practice, metadata is preserved between function calls for 5011** function parameters that are compile-time constants, including literal 5012** values and [parameters] and expressions composed from the same.)^ 5013** 5014** The value of the N parameter to these interfaces should be non-negative. 5015** Future enhancements may make use of negative N values to define new 5016** kinds of function caching behavior. 5017** 5018** These routines must be called from the same thread in which 5019** the SQL function is running. 5020*/ 5021void *sqlite3_get_auxdata(sqlite3_context*, int N); 5022void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5023 5024 5025/* 5026** CAPI3REF: Constants Defining Special Destructor Behavior 5027** 5028** These are special values for the destructor that is passed in as the 5029** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5030** argument is SQLITE_STATIC, it means that the content pointer is constant 5031** and will never change. It does not need to be destroyed. ^The 5032** SQLITE_TRANSIENT value means that the content will likely change in 5033** the near future and that SQLite should make its own private copy of 5034** the content before returning. 5035** 5036** The typedef is necessary to work around problems in certain 5037** C++ compilers. 5038*/ 5039typedef void (*sqlite3_destructor_type)(void*); 5040#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5041#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5042 5043/* 5044** CAPI3REF: Setting The Result Of An SQL Function 5045** METHOD: sqlite3_context 5046** 5047** These routines are used by the xFunc or xFinal callbacks that 5048** implement SQL functions and aggregates. See 5049** [sqlite3_create_function()] and [sqlite3_create_function16()] 5050** for additional information. 5051** 5052** These functions work very much like the [parameter binding] family of 5053** functions used to bind values to host parameters in prepared statements. 5054** Refer to the [SQL parameter] documentation for additional information. 5055** 5056** ^The sqlite3_result_blob() interface sets the result from 5057** an application-defined function to be the BLOB whose content is pointed 5058** to by the second parameter and which is N bytes long where N is the 5059** third parameter. 5060** 5061** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5062** interfaces set the result of the application-defined function to be 5063** a BLOB containing all zero bytes and N bytes in size. 5064** 5065** ^The sqlite3_result_double() interface sets the result from 5066** an application-defined function to be a floating point value specified 5067** by its 2nd argument. 5068** 5069** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5070** cause the implemented SQL function to throw an exception. 5071** ^SQLite uses the string pointed to by the 5072** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5073** as the text of an error message. ^SQLite interprets the error 5074** message string from sqlite3_result_error() as UTF-8. ^SQLite 5075** interprets the string from sqlite3_result_error16() as UTF-16 in native 5076** byte order. ^If the third parameter to sqlite3_result_error() 5077** or sqlite3_result_error16() is negative then SQLite takes as the error 5078** message all text up through the first zero character. 5079** ^If the third parameter to sqlite3_result_error() or 5080** sqlite3_result_error16() is non-negative then SQLite takes that many 5081** bytes (not characters) from the 2nd parameter as the error message. 5082** ^The sqlite3_result_error() and sqlite3_result_error16() 5083** routines make a private copy of the error message text before 5084** they return. Hence, the calling function can deallocate or 5085** modify the text after they return without harm. 5086** ^The sqlite3_result_error_code() function changes the error code 5087** returned by SQLite as a result of an error in a function. ^By default, 5088** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5089** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5090** 5091** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5092** error indicating that a string or BLOB is too long to represent. 5093** 5094** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5095** error indicating that a memory allocation failed. 5096** 5097** ^The sqlite3_result_int() interface sets the return value 5098** of the application-defined function to be the 32-bit signed integer 5099** value given in the 2nd argument. 5100** ^The sqlite3_result_int64() interface sets the return value 5101** of the application-defined function to be the 64-bit signed integer 5102** value given in the 2nd argument. 5103** 5104** ^The sqlite3_result_null() interface sets the return value 5105** of the application-defined function to be NULL. 5106** 5107** ^The sqlite3_result_text(), sqlite3_result_text16(), 5108** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5109** set the return value of the application-defined function to be 5110** a text string which is represented as UTF-8, UTF-16 native byte order, 5111** UTF-16 little endian, or UTF-16 big endian, respectively. 5112** ^The sqlite3_result_text64() interface sets the return value of an 5113** application-defined function to be a text string in an encoding 5114** specified by the fifth (and last) parameter, which must be one 5115** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5116** ^SQLite takes the text result from the application from 5117** the 2nd parameter of the sqlite3_result_text* interfaces. 5118** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5119** is negative, then SQLite takes result text from the 2nd parameter 5120** through the first zero character. 5121** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5122** is non-negative, then as many bytes (not characters) of the text 5123** pointed to by the 2nd parameter are taken as the application-defined 5124** function result. If the 3rd parameter is non-negative, then it 5125** must be the byte offset into the string where the NUL terminator would 5126** appear if the string where NUL terminated. If any NUL characters occur 5127** in the string at a byte offset that is less than the value of the 3rd 5128** parameter, then the resulting string will contain embedded NULs and the 5129** result of expressions operating on strings with embedded NULs is undefined. 5130** ^If the 4th parameter to the sqlite3_result_text* interfaces 5131** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5132** function as the destructor on the text or BLOB result when it has 5133** finished using that result. 5134** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5135** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5136** assumes that the text or BLOB result is in constant space and does not 5137** copy the content of the parameter nor call a destructor on the content 5138** when it has finished using that result. 5139** ^If the 4th parameter to the sqlite3_result_text* interfaces 5140** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5141** then SQLite makes a copy of the result into space obtained 5142** from [sqlite3_malloc()] before it returns. 5143** 5144** ^The sqlite3_result_value() interface sets the result of 5145** the application-defined function to be a copy of the 5146** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5147** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5148** so that the [sqlite3_value] specified in the parameter may change or 5149** be deallocated after sqlite3_result_value() returns without harm. 5150** ^A [protected sqlite3_value] object may always be used where an 5151** [unprotected sqlite3_value] object is required, so either 5152** kind of [sqlite3_value] object can be used with this interface. 5153** 5154** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5155** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5156** also associates the host-language pointer P or type T with that 5157** NULL value such that the pointer can be retrieved within an 5158** [application-defined SQL function] using [sqlite3_value_pointer()]. 5159** ^If the D parameter is not NULL, then it is a pointer to a destructor 5160** for the P parameter. ^SQLite invokes D with P as its only argument 5161** when SQLite is finished with P. The T parameter should be a static 5162** string and preferably a string literal. The sqlite3_result_pointer() 5163** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5164** 5165** If these routines are called from within the different thread 5166** than the one containing the application-defined function that received 5167** the [sqlite3_context] pointer, the results are undefined. 5168*/ 5169void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5170void sqlite3_result_blob64(sqlite3_context*,const void*, 5171 sqlite3_uint64,void(*)(void*)); 5172void sqlite3_result_double(sqlite3_context*, double); 5173void sqlite3_result_error(sqlite3_context*, const char*, int); 5174void sqlite3_result_error16(sqlite3_context*, const void*, int); 5175void sqlite3_result_error_toobig(sqlite3_context*); 5176void sqlite3_result_error_nomem(sqlite3_context*); 5177void sqlite3_result_error_code(sqlite3_context*, int); 5178void sqlite3_result_int(sqlite3_context*, int); 5179void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5180void sqlite3_result_null(sqlite3_context*); 5181void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5182void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5183 void(*)(void*), unsigned char encoding); 5184void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5185void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5186void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5187void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5188void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5189void sqlite3_result_zeroblob(sqlite3_context*, int n); 5190int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5191 5192 5193/* 5194** CAPI3REF: Setting The Subtype Of An SQL Function 5195** METHOD: sqlite3_context 5196** 5197** The sqlite3_result_subtype(C,T) function causes the subtype of 5198** the result from the [application-defined SQL function] with 5199** [sqlite3_context] C to be the value T. Only the lower 8 bits 5200** of the subtype T are preserved in current versions of SQLite; 5201** higher order bits are discarded. 5202** The number of subtype bytes preserved by SQLite might increase 5203** in future releases of SQLite. 5204*/ 5205void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5206 5207/* 5208** CAPI3REF: Define New Collating Sequences 5209** METHOD: sqlite3 5210** 5211** ^These functions add, remove, or modify a [collation] associated 5212** with the [database connection] specified as the first argument. 5213** 5214** ^The name of the collation is a UTF-8 string 5215** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5216** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5217** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5218** considered to be the same name. 5219** 5220** ^(The third argument (eTextRep) must be one of the constants: 5221** <ul> 5222** <li> [SQLITE_UTF8], 5223** <li> [SQLITE_UTF16LE], 5224** <li> [SQLITE_UTF16BE], 5225** <li> [SQLITE_UTF16], or 5226** <li> [SQLITE_UTF16_ALIGNED]. 5227** </ul>)^ 5228** ^The eTextRep argument determines the encoding of strings passed 5229** to the collating function callback, xCallback. 5230** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5231** force strings to be UTF16 with native byte order. 5232** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5233** on an even byte address. 5234** 5235** ^The fourth argument, pArg, is an application data pointer that is passed 5236** through as the first argument to the collating function callback. 5237** 5238** ^The fifth argument, xCallback, is a pointer to the collating function. 5239** ^Multiple collating functions can be registered using the same name but 5240** with different eTextRep parameters and SQLite will use whichever 5241** function requires the least amount of data transformation. 5242** ^If the xCallback argument is NULL then the collating function is 5243** deleted. ^When all collating functions having the same name are deleted, 5244** that collation is no longer usable. 5245** 5246** ^The collating function callback is invoked with a copy of the pArg 5247** application data pointer and with two strings in the encoding specified 5248** by the eTextRep argument. The collating function must return an 5249** integer that is negative, zero, or positive 5250** if the first string is less than, equal to, or greater than the second, 5251** respectively. A collating function must always return the same answer 5252** given the same inputs. If two or more collating functions are registered 5253** to the same collation name (using different eTextRep values) then all 5254** must give an equivalent answer when invoked with equivalent strings. 5255** The collating function must obey the following properties for all 5256** strings A, B, and C: 5257** 5258** <ol> 5259** <li> If A==B then B==A. 5260** <li> If A==B and B==C then A==C. 5261** <li> If A<B THEN B>A. 5262** <li> If A<B and B<C then A<C. 5263** </ol> 5264** 5265** If a collating function fails any of the above constraints and that 5266** collating function is registered and used, then the behavior of SQLite 5267** is undefined. 5268** 5269** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5270** with the addition that the xDestroy callback is invoked on pArg when 5271** the collating function is deleted. 5272** ^Collating functions are deleted when they are overridden by later 5273** calls to the collation creation functions or when the 5274** [database connection] is closed using [sqlite3_close()]. 5275** 5276** ^The xDestroy callback is <u>not</u> called if the 5277** sqlite3_create_collation_v2() function fails. Applications that invoke 5278** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5279** check the return code and dispose of the application data pointer 5280** themselves rather than expecting SQLite to deal with it for them. 5281** This is different from every other SQLite interface. The inconsistency 5282** is unfortunate but cannot be changed without breaking backwards 5283** compatibility. 5284** 5285** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5286*/ 5287int sqlite3_create_collation( 5288 sqlite3*, 5289 const char *zName, 5290 int eTextRep, 5291 void *pArg, 5292 int(*xCompare)(void*,int,const void*,int,const void*) 5293); 5294int sqlite3_create_collation_v2( 5295 sqlite3*, 5296 const char *zName, 5297 int eTextRep, 5298 void *pArg, 5299 int(*xCompare)(void*,int,const void*,int,const void*), 5300 void(*xDestroy)(void*) 5301); 5302int sqlite3_create_collation16( 5303 sqlite3*, 5304 const void *zName, 5305 int eTextRep, 5306 void *pArg, 5307 int(*xCompare)(void*,int,const void*,int,const void*) 5308); 5309 5310/* 5311** CAPI3REF: Collation Needed Callbacks 5312** METHOD: sqlite3 5313** 5314** ^To avoid having to register all collation sequences before a database 5315** can be used, a single callback function may be registered with the 5316** [database connection] to be invoked whenever an undefined collation 5317** sequence is required. 5318** 5319** ^If the function is registered using the sqlite3_collation_needed() API, 5320** then it is passed the names of undefined collation sequences as strings 5321** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5322** the names are passed as UTF-16 in machine native byte order. 5323** ^A call to either function replaces the existing collation-needed callback. 5324** 5325** ^(When the callback is invoked, the first argument passed is a copy 5326** of the second argument to sqlite3_collation_needed() or 5327** sqlite3_collation_needed16(). The second argument is the database 5328** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5329** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5330** sequence function required. The fourth parameter is the name of the 5331** required collation sequence.)^ 5332** 5333** The callback function should register the desired collation using 5334** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5335** [sqlite3_create_collation_v2()]. 5336*/ 5337int sqlite3_collation_needed( 5338 sqlite3*, 5339 void*, 5340 void(*)(void*,sqlite3*,int eTextRep,const char*) 5341); 5342int sqlite3_collation_needed16( 5343 sqlite3*, 5344 void*, 5345 void(*)(void*,sqlite3*,int eTextRep,const void*) 5346); 5347 5348#ifdef SQLITE_HAS_CODEC 5349/* 5350** Specify the key for an encrypted database. This routine should be 5351** called right after sqlite3_open(). 5352** 5353** The code to implement this API is not available in the public release 5354** of SQLite. 5355*/ 5356int sqlite3_key( 5357 sqlite3 *db, /* Database to be rekeyed */ 5358 const void *pKey, int nKey /* The key */ 5359); 5360int sqlite3_key_v2( 5361 sqlite3 *db, /* Database to be rekeyed */ 5362 const char *zDbName, /* Name of the database */ 5363 const void *pKey, int nKey /* The key */ 5364); 5365 5366/* 5367** Change the key on an open database. If the current database is not 5368** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5369** database is decrypted. 5370** 5371** The code to implement this API is not available in the public release 5372** of SQLite. 5373*/ 5374int sqlite3_rekey( 5375 sqlite3 *db, /* Database to be rekeyed */ 5376 const void *pKey, int nKey /* The new key */ 5377); 5378int sqlite3_rekey_v2( 5379 sqlite3 *db, /* Database to be rekeyed */ 5380 const char *zDbName, /* Name of the database */ 5381 const void *pKey, int nKey /* The new key */ 5382); 5383 5384/* 5385** Specify the activation key for a SEE database. Unless 5386** activated, none of the SEE routines will work. 5387*/ 5388void sqlite3_activate_see( 5389 const char *zPassPhrase /* Activation phrase */ 5390); 5391#endif 5392 5393#ifdef SQLITE_ENABLE_CEROD 5394/* 5395** Specify the activation key for a CEROD database. Unless 5396** activated, none of the CEROD routines will work. 5397*/ 5398void sqlite3_activate_cerod( 5399 const char *zPassPhrase /* Activation phrase */ 5400); 5401#endif 5402 5403/* 5404** CAPI3REF: Suspend Execution For A Short Time 5405** 5406** The sqlite3_sleep() function causes the current thread to suspend execution 5407** for at least a number of milliseconds specified in its parameter. 5408** 5409** If the operating system does not support sleep requests with 5410** millisecond time resolution, then the time will be rounded up to 5411** the nearest second. The number of milliseconds of sleep actually 5412** requested from the operating system is returned. 5413** 5414** ^SQLite implements this interface by calling the xSleep() 5415** method of the default [sqlite3_vfs] object. If the xSleep() method 5416** of the default VFS is not implemented correctly, or not implemented at 5417** all, then the behavior of sqlite3_sleep() may deviate from the description 5418** in the previous paragraphs. 5419*/ 5420int sqlite3_sleep(int); 5421 5422/* 5423** CAPI3REF: Name Of The Folder Holding Temporary Files 5424** 5425** ^(If this global variable is made to point to a string which is 5426** the name of a folder (a.k.a. directory), then all temporary files 5427** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5428** will be placed in that directory.)^ ^If this variable 5429** is a NULL pointer, then SQLite performs a search for an appropriate 5430** temporary file directory. 5431** 5432** Applications are strongly discouraged from using this global variable. 5433** It is required to set a temporary folder on Windows Runtime (WinRT). 5434** But for all other platforms, it is highly recommended that applications 5435** neither read nor write this variable. This global variable is a relic 5436** that exists for backwards compatibility of legacy applications and should 5437** be avoided in new projects. 5438** 5439** It is not safe to read or modify this variable in more than one 5440** thread at a time. It is not safe to read or modify this variable 5441** if a [database connection] is being used at the same time in a separate 5442** thread. 5443** It is intended that this variable be set once 5444** as part of process initialization and before any SQLite interface 5445** routines have been called and that this variable remain unchanged 5446** thereafter. 5447** 5448** ^The [temp_store_directory pragma] may modify this variable and cause 5449** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5450** the [temp_store_directory pragma] always assumes that any string 5451** that this variable points to is held in memory obtained from 5452** [sqlite3_malloc] and the pragma may attempt to free that memory 5453** using [sqlite3_free]. 5454** Hence, if this variable is modified directly, either it should be 5455** made NULL or made to point to memory obtained from [sqlite3_malloc] 5456** or else the use of the [temp_store_directory pragma] should be avoided. 5457** Except when requested by the [temp_store_directory pragma], SQLite 5458** does not free the memory that sqlite3_temp_directory points to. If 5459** the application wants that memory to be freed, it must do 5460** so itself, taking care to only do so after all [database connection] 5461** objects have been destroyed. 5462** 5463** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5464** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5465** features that require the use of temporary files may fail. Here is an 5466** example of how to do this using C++ with the Windows Runtime: 5467** 5468** <blockquote><pre> 5469** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5470** TemporaryFolder->Path->Data(); 5471** char zPathBuf[MAX_PATH + 1]; 5472** memset(zPathBuf, 0, sizeof(zPathBuf)); 5473** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5474** NULL, NULL); 5475** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5476** </pre></blockquote> 5477*/ 5478SQLITE_EXTERN char *sqlite3_temp_directory; 5479 5480/* 5481** CAPI3REF: Name Of The Folder Holding Database Files 5482** 5483** ^(If this global variable is made to point to a string which is 5484** the name of a folder (a.k.a. directory), then all database files 5485** specified with a relative pathname and created or accessed by 5486** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5487** to be relative to that directory.)^ ^If this variable is a NULL 5488** pointer, then SQLite assumes that all database files specified 5489** with a relative pathname are relative to the current directory 5490** for the process. Only the windows VFS makes use of this global 5491** variable; it is ignored by the unix VFS. 5492** 5493** Changing the value of this variable while a database connection is 5494** open can result in a corrupt database. 5495** 5496** It is not safe to read or modify this variable in more than one 5497** thread at a time. It is not safe to read or modify this variable 5498** if a [database connection] is being used at the same time in a separate 5499** thread. 5500** It is intended that this variable be set once 5501** as part of process initialization and before any SQLite interface 5502** routines have been called and that this variable remain unchanged 5503** thereafter. 5504** 5505** ^The [data_store_directory pragma] may modify this variable and cause 5506** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5507** the [data_store_directory pragma] always assumes that any string 5508** that this variable points to is held in memory obtained from 5509** [sqlite3_malloc] and the pragma may attempt to free that memory 5510** using [sqlite3_free]. 5511** Hence, if this variable is modified directly, either it should be 5512** made NULL or made to point to memory obtained from [sqlite3_malloc] 5513** or else the use of the [data_store_directory pragma] should be avoided. 5514*/ 5515SQLITE_EXTERN char *sqlite3_data_directory; 5516 5517/* 5518** CAPI3REF: Test For Auto-Commit Mode 5519** KEYWORDS: {autocommit mode} 5520** METHOD: sqlite3 5521** 5522** ^The sqlite3_get_autocommit() interface returns non-zero or 5523** zero if the given database connection is or is not in autocommit mode, 5524** respectively. ^Autocommit mode is on by default. 5525** ^Autocommit mode is disabled by a [BEGIN] statement. 5526** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5527** 5528** If certain kinds of errors occur on a statement within a multi-statement 5529** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5530** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5531** transaction might be rolled back automatically. The only way to 5532** find out whether SQLite automatically rolled back the transaction after 5533** an error is to use this function. 5534** 5535** If another thread changes the autocommit status of the database 5536** connection while this routine is running, then the return value 5537** is undefined. 5538*/ 5539int sqlite3_get_autocommit(sqlite3*); 5540 5541/* 5542** CAPI3REF: Find The Database Handle Of A Prepared Statement 5543** METHOD: sqlite3_stmt 5544** 5545** ^The sqlite3_db_handle interface returns the [database connection] handle 5546** to which a [prepared statement] belongs. ^The [database connection] 5547** returned by sqlite3_db_handle is the same [database connection] 5548** that was the first argument 5549** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5550** create the statement in the first place. 5551*/ 5552sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5553 5554/* 5555** CAPI3REF: Return The Filename For A Database Connection 5556** METHOD: sqlite3 5557** 5558** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5559** associated with database N of connection D. ^The main database file 5560** has the name "main". If there is no attached database N on the database 5561** connection D, or if database N is a temporary or in-memory database, then 5562** a NULL pointer is returned. 5563** 5564** ^The filename returned by this function is the output of the 5565** xFullPathname method of the [VFS]. ^In other words, the filename 5566** will be an absolute pathname, even if the filename used 5567** to open the database originally was a URI or relative pathname. 5568*/ 5569const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5570 5571/* 5572** CAPI3REF: Determine if a database is read-only 5573** METHOD: sqlite3 5574** 5575** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5576** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5577** the name of a database on connection D. 5578*/ 5579int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5580 5581/* 5582** CAPI3REF: Find the next prepared statement 5583** METHOD: sqlite3 5584** 5585** ^This interface returns a pointer to the next [prepared statement] after 5586** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5587** then this interface returns a pointer to the first prepared statement 5588** associated with the database connection pDb. ^If no prepared statement 5589** satisfies the conditions of this routine, it returns NULL. 5590** 5591** The [database connection] pointer D in a call to 5592** [sqlite3_next_stmt(D,S)] must refer to an open database 5593** connection and in particular must not be a NULL pointer. 5594*/ 5595sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5596 5597/* 5598** CAPI3REF: Commit And Rollback Notification Callbacks 5599** METHOD: sqlite3 5600** 5601** ^The sqlite3_commit_hook() interface registers a callback 5602** function to be invoked whenever a transaction is [COMMIT | committed]. 5603** ^Any callback set by a previous call to sqlite3_commit_hook() 5604** for the same database connection is overridden. 5605** ^The sqlite3_rollback_hook() interface registers a callback 5606** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5607** ^Any callback set by a previous call to sqlite3_rollback_hook() 5608** for the same database connection is overridden. 5609** ^The pArg argument is passed through to the callback. 5610** ^If the callback on a commit hook function returns non-zero, 5611** then the commit is converted into a rollback. 5612** 5613** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5614** return the P argument from the previous call of the same function 5615** on the same [database connection] D, or NULL for 5616** the first call for each function on D. 5617** 5618** The commit and rollback hook callbacks are not reentrant. 5619** The callback implementation must not do anything that will modify 5620** the database connection that invoked the callback. Any actions 5621** to modify the database connection must be deferred until after the 5622** completion of the [sqlite3_step()] call that triggered the commit 5623** or rollback hook in the first place. 5624** Note that running any other SQL statements, including SELECT statements, 5625** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5626** the database connections for the meaning of "modify" in this paragraph. 5627** 5628** ^Registering a NULL function disables the callback. 5629** 5630** ^When the commit hook callback routine returns zero, the [COMMIT] 5631** operation is allowed to continue normally. ^If the commit hook 5632** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5633** ^The rollback hook is invoked on a rollback that results from a commit 5634** hook returning non-zero, just as it would be with any other rollback. 5635** 5636** ^For the purposes of this API, a transaction is said to have been 5637** rolled back if an explicit "ROLLBACK" statement is executed, or 5638** an error or constraint causes an implicit rollback to occur. 5639** ^The rollback callback is not invoked if a transaction is 5640** automatically rolled back because the database connection is closed. 5641** 5642** See also the [sqlite3_update_hook()] interface. 5643*/ 5644void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5645void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5646 5647/* 5648** CAPI3REF: Data Change Notification Callbacks 5649** METHOD: sqlite3 5650** 5651** ^The sqlite3_update_hook() interface registers a callback function 5652** with the [database connection] identified by the first argument 5653** to be invoked whenever a row is updated, inserted or deleted in 5654** a [rowid table]. 5655** ^Any callback set by a previous call to this function 5656** for the same database connection is overridden. 5657** 5658** ^The second argument is a pointer to the function to invoke when a 5659** row is updated, inserted or deleted in a rowid table. 5660** ^The first argument to the callback is a copy of the third argument 5661** to sqlite3_update_hook(). 5662** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5663** or [SQLITE_UPDATE], depending on the operation that caused the callback 5664** to be invoked. 5665** ^The third and fourth arguments to the callback contain pointers to the 5666** database and table name containing the affected row. 5667** ^The final callback parameter is the [rowid] of the row. 5668** ^In the case of an update, this is the [rowid] after the update takes place. 5669** 5670** ^(The update hook is not invoked when internal system tables are 5671** modified (i.e. sqlite_master and sqlite_sequence).)^ 5672** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5673** 5674** ^In the current implementation, the update hook 5675** is not invoked when conflicting rows are deleted because of an 5676** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5677** invoked when rows are deleted using the [truncate optimization]. 5678** The exceptions defined in this paragraph might change in a future 5679** release of SQLite. 5680** 5681** The update hook implementation must not do anything that will modify 5682** the database connection that invoked the update hook. Any actions 5683** to modify the database connection must be deferred until after the 5684** completion of the [sqlite3_step()] call that triggered the update hook. 5685** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5686** database connections for the meaning of "modify" in this paragraph. 5687** 5688** ^The sqlite3_update_hook(D,C,P) function 5689** returns the P argument from the previous call 5690** on the same [database connection] D, or NULL for 5691** the first call on D. 5692** 5693** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5694** and [sqlite3_preupdate_hook()] interfaces. 5695*/ 5696void *sqlite3_update_hook( 5697 sqlite3*, 5698 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5699 void* 5700); 5701 5702/* 5703** CAPI3REF: Enable Or Disable Shared Pager Cache 5704** 5705** ^(This routine enables or disables the sharing of the database cache 5706** and schema data structures between [database connection | connections] 5707** to the same database. Sharing is enabled if the argument is true 5708** and disabled if the argument is false.)^ 5709** 5710** ^Cache sharing is enabled and disabled for an entire process. 5711** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5712** In prior versions of SQLite, 5713** sharing was enabled or disabled for each thread separately. 5714** 5715** ^(The cache sharing mode set by this interface effects all subsequent 5716** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5717** Existing database connections continue use the sharing mode 5718** that was in effect at the time they were opened.)^ 5719** 5720** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5721** successfully. An [error code] is returned otherwise.)^ 5722** 5723** ^Shared cache is disabled by default. But this might change in 5724** future releases of SQLite. Applications that care about shared 5725** cache setting should set it explicitly. 5726** 5727** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5728** and will always return SQLITE_MISUSE. On those systems, 5729** shared cache mode should be enabled per-database connection via 5730** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5731** 5732** This interface is threadsafe on processors where writing a 5733** 32-bit integer is atomic. 5734** 5735** See Also: [SQLite Shared-Cache Mode] 5736*/ 5737int sqlite3_enable_shared_cache(int); 5738 5739/* 5740** CAPI3REF: Attempt To Free Heap Memory 5741** 5742** ^The sqlite3_release_memory() interface attempts to free N bytes 5743** of heap memory by deallocating non-essential memory allocations 5744** held by the database library. Memory used to cache database 5745** pages to improve performance is an example of non-essential memory. 5746** ^sqlite3_release_memory() returns the number of bytes actually freed, 5747** which might be more or less than the amount requested. 5748** ^The sqlite3_release_memory() routine is a no-op returning zero 5749** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5750** 5751** See also: [sqlite3_db_release_memory()] 5752*/ 5753int sqlite3_release_memory(int); 5754 5755/* 5756** CAPI3REF: Free Memory Used By A Database Connection 5757** METHOD: sqlite3 5758** 5759** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5760** memory as possible from database connection D. Unlike the 5761** [sqlite3_release_memory()] interface, this interface is in effect even 5762** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5763** omitted. 5764** 5765** See also: [sqlite3_release_memory()] 5766*/ 5767int sqlite3_db_release_memory(sqlite3*); 5768 5769/* 5770** CAPI3REF: Impose A Limit On Heap Size 5771** 5772** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5773** soft limit on the amount of heap memory that may be allocated by SQLite. 5774** ^SQLite strives to keep heap memory utilization below the soft heap 5775** limit by reducing the number of pages held in the page cache 5776** as heap memory usages approaches the limit. 5777** ^The soft heap limit is "soft" because even though SQLite strives to stay 5778** below the limit, it will exceed the limit rather than generate 5779** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5780** is advisory only. 5781** 5782** ^The return value from sqlite3_soft_heap_limit64() is the size of 5783** the soft heap limit prior to the call, or negative in the case of an 5784** error. ^If the argument N is negative 5785** then no change is made to the soft heap limit. Hence, the current 5786** size of the soft heap limit can be determined by invoking 5787** sqlite3_soft_heap_limit64() with a negative argument. 5788** 5789** ^If the argument N is zero then the soft heap limit is disabled. 5790** 5791** ^(The soft heap limit is not enforced in the current implementation 5792** if one or more of following conditions are true: 5793** 5794** <ul> 5795** <li> The soft heap limit is set to zero. 5796** <li> Memory accounting is disabled using a combination of the 5797** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5798** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5799** <li> An alternative page cache implementation is specified using 5800** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5801** <li> The page cache allocates from its own memory pool supplied 5802** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5803** from the heap. 5804** </ul>)^ 5805** 5806** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5807** the soft heap limit is enforced 5808** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5809** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5810** the soft heap limit is enforced on every memory allocation. Without 5811** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5812** when memory is allocated by the page cache. Testing suggests that because 5813** the page cache is the predominate memory user in SQLite, most 5814** applications will achieve adequate soft heap limit enforcement without 5815** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5816** 5817** The circumstances under which SQLite will enforce the soft heap limit may 5818** changes in future releases of SQLite. 5819*/ 5820sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5821 5822/* 5823** CAPI3REF: Deprecated Soft Heap Limit Interface 5824** DEPRECATED 5825** 5826** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5827** interface. This routine is provided for historical compatibility 5828** only. All new applications should use the 5829** [sqlite3_soft_heap_limit64()] interface rather than this one. 5830*/ 5831SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5832 5833 5834/* 5835** CAPI3REF: Extract Metadata About A Column Of A Table 5836** METHOD: sqlite3 5837** 5838** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5839** information about column C of table T in database D 5840** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5841** interface returns SQLITE_OK and fills in the non-NULL pointers in 5842** the final five arguments with appropriate values if the specified 5843** column exists. ^The sqlite3_table_column_metadata() interface returns 5844** SQLITE_ERROR and if the specified column does not exist. 5845** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5846** NULL pointer, then this routine simply checks for the existence of the 5847** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5848** does not. If the table name parameter T in a call to 5849** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5850** undefined behavior. 5851** 5852** ^The column is identified by the second, third and fourth parameters to 5853** this function. ^(The second parameter is either the name of the database 5854** (i.e. "main", "temp", or an attached database) containing the specified 5855** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5856** for the table using the same algorithm used by the database engine to 5857** resolve unqualified table references. 5858** 5859** ^The third and fourth parameters to this function are the table and column 5860** name of the desired column, respectively. 5861** 5862** ^Metadata is returned by writing to the memory locations passed as the 5th 5863** and subsequent parameters to this function. ^Any of these arguments may be 5864** NULL, in which case the corresponding element of metadata is omitted. 5865** 5866** ^(<blockquote> 5867** <table border="1"> 5868** <tr><th> Parameter <th> Output<br>Type <th> Description 5869** 5870** <tr><td> 5th <td> const char* <td> Data type 5871** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5872** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5873** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5874** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5875** </table> 5876** </blockquote>)^ 5877** 5878** ^The memory pointed to by the character pointers returned for the 5879** declaration type and collation sequence is valid until the next 5880** call to any SQLite API function. 5881** 5882** ^If the specified table is actually a view, an [error code] is returned. 5883** 5884** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5885** is not a [WITHOUT ROWID] table and an 5886** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5887** parameters are set for the explicitly declared column. ^(If there is no 5888** [INTEGER PRIMARY KEY] column, then the outputs 5889** for the [rowid] are set as follows: 5890** 5891** <pre> 5892** data type: "INTEGER" 5893** collation sequence: "BINARY" 5894** not null: 0 5895** primary key: 1 5896** auto increment: 0 5897** </pre>)^ 5898** 5899** ^This function causes all database schemas to be read from disk and 5900** parsed, if that has not already been done, and returns an error if 5901** any errors are encountered while loading the schema. 5902*/ 5903int sqlite3_table_column_metadata( 5904 sqlite3 *db, /* Connection handle */ 5905 const char *zDbName, /* Database name or NULL */ 5906 const char *zTableName, /* Table name */ 5907 const char *zColumnName, /* Column name */ 5908 char const **pzDataType, /* OUTPUT: Declared data type */ 5909 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5910 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5911 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5912 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5913); 5914 5915/* 5916** CAPI3REF: Load An Extension 5917** METHOD: sqlite3 5918** 5919** ^This interface loads an SQLite extension library from the named file. 5920** 5921** ^The sqlite3_load_extension() interface attempts to load an 5922** [SQLite extension] library contained in the file zFile. If 5923** the file cannot be loaded directly, attempts are made to load 5924** with various operating-system specific extensions added. 5925** So for example, if "samplelib" cannot be loaded, then names like 5926** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5927** be tried also. 5928** 5929** ^The entry point is zProc. 5930** ^(zProc may be 0, in which case SQLite will try to come up with an 5931** entry point name on its own. It first tries "sqlite3_extension_init". 5932** If that does not work, it constructs a name "sqlite3_X_init" where the 5933** X is consists of the lower-case equivalent of all ASCII alphabetic 5934** characters in the filename from the last "/" to the first following 5935** "." and omitting any initial "lib".)^ 5936** ^The sqlite3_load_extension() interface returns 5937** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5938** ^If an error occurs and pzErrMsg is not 0, then the 5939** [sqlite3_load_extension()] interface shall attempt to 5940** fill *pzErrMsg with error message text stored in memory 5941** obtained from [sqlite3_malloc()]. The calling function 5942** should free this memory by calling [sqlite3_free()]. 5943** 5944** ^Extension loading must be enabled using 5945** [sqlite3_enable_load_extension()] or 5946** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5947** prior to calling this API, 5948** otherwise an error will be returned. 5949** 5950** <b>Security warning:</b> It is recommended that the 5951** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5952** interface. The use of the [sqlite3_enable_load_extension()] interface 5953** should be avoided. This will keep the SQL function [load_extension()] 5954** disabled and prevent SQL injections from giving attackers 5955** access to extension loading capabilities. 5956** 5957** See also the [load_extension() SQL function]. 5958*/ 5959int sqlite3_load_extension( 5960 sqlite3 *db, /* Load the extension into this database connection */ 5961 const char *zFile, /* Name of the shared library containing extension */ 5962 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5963 char **pzErrMsg /* Put error message here if not 0 */ 5964); 5965 5966/* 5967** CAPI3REF: Enable Or Disable Extension Loading 5968** METHOD: sqlite3 5969** 5970** ^So as not to open security holes in older applications that are 5971** unprepared to deal with [extension loading], and as a means of disabling 5972** [extension loading] while evaluating user-entered SQL, the following API 5973** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5974** 5975** ^Extension loading is off by default. 5976** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5977** to turn extension loading on and call it with onoff==0 to turn 5978** it back off again. 5979** 5980** ^This interface enables or disables both the C-API 5981** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5982** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5983** to enable or disable only the C-API.)^ 5984** 5985** <b>Security warning:</b> It is recommended that extension loading 5986** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5987** rather than this interface, so the [load_extension()] SQL function 5988** remains disabled. This will prevent SQL injections from giving attackers 5989** access to extension loading capabilities. 5990*/ 5991int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5992 5993/* 5994** CAPI3REF: Automatically Load Statically Linked Extensions 5995** 5996** ^This interface causes the xEntryPoint() function to be invoked for 5997** each new [database connection] that is created. The idea here is that 5998** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5999** that is to be automatically loaded into all new database connections. 6000** 6001** ^(Even though the function prototype shows that xEntryPoint() takes 6002** no arguments and returns void, SQLite invokes xEntryPoint() with three 6003** arguments and expects an integer result as if the signature of the 6004** entry point where as follows: 6005** 6006** <blockquote><pre> 6007** int xEntryPoint( 6008** sqlite3 *db, 6009** const char **pzErrMsg, 6010** const struct sqlite3_api_routines *pThunk 6011** ); 6012** </pre></blockquote>)^ 6013** 6014** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6015** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6016** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6017** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6018** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6019** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6020** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6021** 6022** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6023** on the list of automatic extensions is a harmless no-op. ^No entry point 6024** will be called more than once for each database connection that is opened. 6025** 6026** See also: [sqlite3_reset_auto_extension()] 6027** and [sqlite3_cancel_auto_extension()] 6028*/ 6029int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6030 6031/* 6032** CAPI3REF: Cancel Automatic Extension Loading 6033** 6034** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6035** initialization routine X that was registered using a prior call to 6036** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6037** routine returns 1 if initialization routine X was successfully 6038** unregistered and it returns 0 if X was not on the list of initialization 6039** routines. 6040*/ 6041int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6042 6043/* 6044** CAPI3REF: Reset Automatic Extension Loading 6045** 6046** ^This interface disables all automatic extensions previously 6047** registered using [sqlite3_auto_extension()]. 6048*/ 6049void sqlite3_reset_auto_extension(void); 6050 6051/* 6052** The interface to the virtual-table mechanism is currently considered 6053** to be experimental. The interface might change in incompatible ways. 6054** If this is a problem for you, do not use the interface at this time. 6055** 6056** When the virtual-table mechanism stabilizes, we will declare the 6057** interface fixed, support it indefinitely, and remove this comment. 6058*/ 6059 6060/* 6061** Structures used by the virtual table interface 6062*/ 6063typedef struct sqlite3_vtab sqlite3_vtab; 6064typedef struct sqlite3_index_info sqlite3_index_info; 6065typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6066typedef struct sqlite3_module sqlite3_module; 6067 6068/* 6069** CAPI3REF: Virtual Table Object 6070** KEYWORDS: sqlite3_module {virtual table module} 6071** 6072** This structure, sometimes called a "virtual table module", 6073** defines the implementation of a [virtual tables]. 6074** This structure consists mostly of methods for the module. 6075** 6076** ^A virtual table module is created by filling in a persistent 6077** instance of this structure and passing a pointer to that instance 6078** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6079** ^The registration remains valid until it is replaced by a different 6080** module or until the [database connection] closes. The content 6081** of this structure must not change while it is registered with 6082** any database connection. 6083*/ 6084struct sqlite3_module { 6085 int iVersion; 6086 int (*xCreate)(sqlite3*, void *pAux, 6087 int argc, const char *const*argv, 6088 sqlite3_vtab **ppVTab, char**); 6089 int (*xConnect)(sqlite3*, void *pAux, 6090 int argc, const char *const*argv, 6091 sqlite3_vtab **ppVTab, char**); 6092 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6093 int (*xDisconnect)(sqlite3_vtab *pVTab); 6094 int (*xDestroy)(sqlite3_vtab *pVTab); 6095 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6096 int (*xClose)(sqlite3_vtab_cursor*); 6097 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6098 int argc, sqlite3_value **argv); 6099 int (*xNext)(sqlite3_vtab_cursor*); 6100 int (*xEof)(sqlite3_vtab_cursor*); 6101 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6102 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6103 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6104 int (*xBegin)(sqlite3_vtab *pVTab); 6105 int (*xSync)(sqlite3_vtab *pVTab); 6106 int (*xCommit)(sqlite3_vtab *pVTab); 6107 int (*xRollback)(sqlite3_vtab *pVTab); 6108 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6109 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6110 void **ppArg); 6111 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6112 /* The methods above are in version 1 of the sqlite_module object. Those 6113 ** below are for version 2 and greater. */ 6114 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6115 int (*xRelease)(sqlite3_vtab *pVTab, int); 6116 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6117}; 6118 6119/* 6120** CAPI3REF: Virtual Table Indexing Information 6121** KEYWORDS: sqlite3_index_info 6122** 6123** The sqlite3_index_info structure and its substructures is used as part 6124** of the [virtual table] interface to 6125** pass information into and receive the reply from the [xBestIndex] 6126** method of a [virtual table module]. The fields under **Inputs** are the 6127** inputs to xBestIndex and are read-only. xBestIndex inserts its 6128** results into the **Outputs** fields. 6129** 6130** ^(The aConstraint[] array records WHERE clause constraints of the form: 6131** 6132** <blockquote>column OP expr</blockquote> 6133** 6134** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6135** stored in aConstraint[].op using one of the 6136** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6137** ^(The index of the column is stored in 6138** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6139** expr on the right-hand side can be evaluated (and thus the constraint 6140** is usable) and false if it cannot.)^ 6141** 6142** ^The optimizer automatically inverts terms of the form "expr OP column" 6143** and makes other simplifications to the WHERE clause in an attempt to 6144** get as many WHERE clause terms into the form shown above as possible. 6145** ^The aConstraint[] array only reports WHERE clause terms that are 6146** relevant to the particular virtual table being queried. 6147** 6148** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6149** ^Each term of aOrderBy records a column of the ORDER BY clause. 6150** 6151** The colUsed field indicates which columns of the virtual table may be 6152** required by the current scan. Virtual table columns are numbered from 6153** zero in the order in which they appear within the CREATE TABLE statement 6154** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6155** the corresponding bit is set within the colUsed mask if the column may be 6156** required by SQLite. If the table has at least 64 columns and any column 6157** to the right of the first 63 is required, then bit 63 of colUsed is also 6158** set. In other words, column iCol may be required if the expression 6159** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6160** non-zero. 6161** 6162** The [xBestIndex] method must fill aConstraintUsage[] with information 6163** about what parameters to pass to xFilter. ^If argvIndex>0 then 6164** the right-hand side of the corresponding aConstraint[] is evaluated 6165** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6166** is true, then the constraint is assumed to be fully handled by the 6167** virtual table and is not checked again by SQLite.)^ 6168** 6169** ^The idxNum and idxPtr values are recorded and passed into the 6170** [xFilter] method. 6171** ^[sqlite3_free()] is used to free idxPtr if and only if 6172** needToFreeIdxPtr is true. 6173** 6174** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6175** the correct order to satisfy the ORDER BY clause so that no separate 6176** sorting step is required. 6177** 6178** ^The estimatedCost value is an estimate of the cost of a particular 6179** strategy. A cost of N indicates that the cost of the strategy is similar 6180** to a linear scan of an SQLite table with N rows. A cost of log(N) 6181** indicates that the expense of the operation is similar to that of a 6182** binary search on a unique indexed field of an SQLite table with N rows. 6183** 6184** ^The estimatedRows value is an estimate of the number of rows that 6185** will be returned by the strategy. 6186** 6187** The xBestIndex method may optionally populate the idxFlags field with a 6188** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6189** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6190** assumes that the strategy may visit at most one row. 6191** 6192** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6193** SQLite also assumes that if a call to the xUpdate() method is made as 6194** part of the same statement to delete or update a virtual table row and the 6195** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6196** any database changes. In other words, if the xUpdate() returns 6197** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6198** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6199** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6200** the xUpdate method are automatically rolled back by SQLite. 6201** 6202** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6203** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6204** If a virtual table extension is 6205** used with an SQLite version earlier than 3.8.2, the results of attempting 6206** to read or write the estimatedRows field are undefined (but are likely 6207** to included crashing the application). The estimatedRows field should 6208** therefore only be used if [sqlite3_libversion_number()] returns a 6209** value greater than or equal to 3008002. Similarly, the idxFlags field 6210** was added for [version 3.9.0] ([dateof:3.9.0]). 6211** It may therefore only be used if 6212** sqlite3_libversion_number() returns a value greater than or equal to 6213** 3009000. 6214*/ 6215struct sqlite3_index_info { 6216 /* Inputs */ 6217 int nConstraint; /* Number of entries in aConstraint */ 6218 struct sqlite3_index_constraint { 6219 int iColumn; /* Column constrained. -1 for ROWID */ 6220 unsigned char op; /* Constraint operator */ 6221 unsigned char usable; /* True if this constraint is usable */ 6222 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6223 } *aConstraint; /* Table of WHERE clause constraints */ 6224 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6225 struct sqlite3_index_orderby { 6226 int iColumn; /* Column number */ 6227 unsigned char desc; /* True for DESC. False for ASC. */ 6228 } *aOrderBy; /* The ORDER BY clause */ 6229 /* Outputs */ 6230 struct sqlite3_index_constraint_usage { 6231 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6232 unsigned char omit; /* Do not code a test for this constraint */ 6233 } *aConstraintUsage; 6234 int idxNum; /* Number used to identify the index */ 6235 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6236 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6237 int orderByConsumed; /* True if output is already ordered */ 6238 double estimatedCost; /* Estimated cost of using this index */ 6239 /* Fields below are only available in SQLite 3.8.2 and later */ 6240 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6241 /* Fields below are only available in SQLite 3.9.0 and later */ 6242 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6243 /* Fields below are only available in SQLite 3.10.0 and later */ 6244 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6245}; 6246 6247/* 6248** CAPI3REF: Virtual Table Scan Flags 6249*/ 6250#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6251 6252/* 6253** CAPI3REF: Virtual Table Constraint Operator Codes 6254** 6255** These macros defined the allowed values for the 6256** [sqlite3_index_info].aConstraint[].op field. Each value represents 6257** an operator that is part of a constraint term in the wHERE clause of 6258** a query that uses a [virtual table]. 6259*/ 6260#define SQLITE_INDEX_CONSTRAINT_EQ 2 6261#define SQLITE_INDEX_CONSTRAINT_GT 4 6262#define SQLITE_INDEX_CONSTRAINT_LE 8 6263#define SQLITE_INDEX_CONSTRAINT_LT 16 6264#define SQLITE_INDEX_CONSTRAINT_GE 32 6265#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6266#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6267#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6268#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6269#define SQLITE_INDEX_CONSTRAINT_NE 68 6270#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6271#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6272#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6273#define SQLITE_INDEX_CONSTRAINT_IS 72 6274 6275/* 6276** CAPI3REF: Register A Virtual Table Implementation 6277** METHOD: sqlite3 6278** 6279** ^These routines are used to register a new [virtual table module] name. 6280** ^Module names must be registered before 6281** creating a new [virtual table] using the module and before using a 6282** preexisting [virtual table] for the module. 6283** 6284** ^The module name is registered on the [database connection] specified 6285** by the first parameter. ^The name of the module is given by the 6286** second parameter. ^The third parameter is a pointer to 6287** the implementation of the [virtual table module]. ^The fourth 6288** parameter is an arbitrary client data pointer that is passed through 6289** into the [xCreate] and [xConnect] methods of the virtual table module 6290** when a new virtual table is be being created or reinitialized. 6291** 6292** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6293** is a pointer to a destructor for the pClientData. ^SQLite will 6294** invoke the destructor function (if it is not NULL) when SQLite 6295** no longer needs the pClientData pointer. ^The destructor will also 6296** be invoked if the call to sqlite3_create_module_v2() fails. 6297** ^The sqlite3_create_module() 6298** interface is equivalent to sqlite3_create_module_v2() with a NULL 6299** destructor. 6300*/ 6301int sqlite3_create_module( 6302 sqlite3 *db, /* SQLite connection to register module with */ 6303 const char *zName, /* Name of the module */ 6304 const sqlite3_module *p, /* Methods for the module */ 6305 void *pClientData /* Client data for xCreate/xConnect */ 6306); 6307int sqlite3_create_module_v2( 6308 sqlite3 *db, /* SQLite connection to register module with */ 6309 const char *zName, /* Name of the module */ 6310 const sqlite3_module *p, /* Methods for the module */ 6311 void *pClientData, /* Client data for xCreate/xConnect */ 6312 void(*xDestroy)(void*) /* Module destructor function */ 6313); 6314 6315/* 6316** CAPI3REF: Virtual Table Instance Object 6317** KEYWORDS: sqlite3_vtab 6318** 6319** Every [virtual table module] implementation uses a subclass 6320** of this object to describe a particular instance 6321** of the [virtual table]. Each subclass will 6322** be tailored to the specific needs of the module implementation. 6323** The purpose of this superclass is to define certain fields that are 6324** common to all module implementations. 6325** 6326** ^Virtual tables methods can set an error message by assigning a 6327** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6328** take care that any prior string is freed by a call to [sqlite3_free()] 6329** prior to assigning a new string to zErrMsg. ^After the error message 6330** is delivered up to the client application, the string will be automatically 6331** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6332*/ 6333struct sqlite3_vtab { 6334 const sqlite3_module *pModule; /* The module for this virtual table */ 6335 int nRef; /* Number of open cursors */ 6336 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6337 /* Virtual table implementations will typically add additional fields */ 6338}; 6339 6340/* 6341** CAPI3REF: Virtual Table Cursor Object 6342** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6343** 6344** Every [virtual table module] implementation uses a subclass of the 6345** following structure to describe cursors that point into the 6346** [virtual table] and are used 6347** to loop through the virtual table. Cursors are created using the 6348** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6349** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6350** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6351** of the module. Each module implementation will define 6352** the content of a cursor structure to suit its own needs. 6353** 6354** This superclass exists in order to define fields of the cursor that 6355** are common to all implementations. 6356*/ 6357struct sqlite3_vtab_cursor { 6358 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6359 /* Virtual table implementations will typically add additional fields */ 6360}; 6361 6362/* 6363** CAPI3REF: Declare The Schema Of A Virtual Table 6364** 6365** ^The [xCreate] and [xConnect] methods of a 6366** [virtual table module] call this interface 6367** to declare the format (the names and datatypes of the columns) of 6368** the virtual tables they implement. 6369*/ 6370int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6371 6372/* 6373** CAPI3REF: Overload A Function For A Virtual Table 6374** METHOD: sqlite3 6375** 6376** ^(Virtual tables can provide alternative implementations of functions 6377** using the [xFindFunction] method of the [virtual table module]. 6378** But global versions of those functions 6379** must exist in order to be overloaded.)^ 6380** 6381** ^(This API makes sure a global version of a function with a particular 6382** name and number of parameters exists. If no such function exists 6383** before this API is called, a new function is created.)^ ^The implementation 6384** of the new function always causes an exception to be thrown. So 6385** the new function is not good for anything by itself. Its only 6386** purpose is to be a placeholder function that can be overloaded 6387** by a [virtual table]. 6388*/ 6389int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6390 6391/* 6392** The interface to the virtual-table mechanism defined above (back up 6393** to a comment remarkably similar to this one) is currently considered 6394** to be experimental. The interface might change in incompatible ways. 6395** If this is a problem for you, do not use the interface at this time. 6396** 6397** When the virtual-table mechanism stabilizes, we will declare the 6398** interface fixed, support it indefinitely, and remove this comment. 6399*/ 6400 6401/* 6402** CAPI3REF: A Handle To An Open BLOB 6403** KEYWORDS: {BLOB handle} {BLOB handles} 6404** 6405** An instance of this object represents an open BLOB on which 6406** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6407** ^Objects of this type are created by [sqlite3_blob_open()] 6408** and destroyed by [sqlite3_blob_close()]. 6409** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6410** can be used to read or write small subsections of the BLOB. 6411** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6412*/ 6413typedef struct sqlite3_blob sqlite3_blob; 6414 6415/* 6416** CAPI3REF: Open A BLOB For Incremental I/O 6417** METHOD: sqlite3 6418** CONSTRUCTOR: sqlite3_blob 6419** 6420** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6421** in row iRow, column zColumn, table zTable in database zDb; 6422** in other words, the same BLOB that would be selected by: 6423** 6424** <pre> 6425** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6426** </pre>)^ 6427** 6428** ^(Parameter zDb is not the filename that contains the database, but 6429** rather the symbolic name of the database. For attached databases, this is 6430** the name that appears after the AS keyword in the [ATTACH] statement. 6431** For the main database file, the database name is "main". For TEMP 6432** tables, the database name is "temp".)^ 6433** 6434** ^If the flags parameter is non-zero, then the BLOB is opened for read 6435** and write access. ^If the flags parameter is zero, the BLOB is opened for 6436** read-only access. 6437** 6438** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6439** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6440** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6441** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6442** on *ppBlob after this function it returns. 6443** 6444** This function fails with SQLITE_ERROR if any of the following are true: 6445** <ul> 6446** <li> ^(Database zDb does not exist)^, 6447** <li> ^(Table zTable does not exist within database zDb)^, 6448** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6449** <li> ^(Column zColumn does not exist)^, 6450** <li> ^(Row iRow is not present in the table)^, 6451** <li> ^(The specified column of row iRow contains a value that is not 6452** a TEXT or BLOB value)^, 6453** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6454** constraint and the blob is being opened for read/write access)^, 6455** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6456** column zColumn is part of a [child key] definition and the blob is 6457** being opened for read/write access)^. 6458** </ul> 6459** 6460** ^Unless it returns SQLITE_MISUSE, this function sets the 6461** [database connection] error code and message accessible via 6462** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6463** 6464** A BLOB referenced by sqlite3_blob_open() may be read using the 6465** [sqlite3_blob_read()] interface and modified by using 6466** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6467** different row of the same table using the [sqlite3_blob_reopen()] 6468** interface. However, the column, table, or database of a [BLOB handle] 6469** cannot be changed after the [BLOB handle] is opened. 6470** 6471** ^(If the row that a BLOB handle points to is modified by an 6472** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6473** then the BLOB handle is marked as "expired". 6474** This is true if any column of the row is changed, even a column 6475** other than the one the BLOB handle is open on.)^ 6476** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6477** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6478** ^(Changes written into a BLOB prior to the BLOB expiring are not 6479** rolled back by the expiration of the BLOB. Such changes will eventually 6480** commit if the transaction continues to completion.)^ 6481** 6482** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6483** the opened blob. ^The size of a blob may not be changed by this 6484** interface. Use the [UPDATE] SQL command to change the size of a 6485** blob. 6486** 6487** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6488** and the built-in [zeroblob] SQL function may be used to create a 6489** zero-filled blob to read or write using the incremental-blob interface. 6490** 6491** To avoid a resource leak, every open [BLOB handle] should eventually 6492** be released by a call to [sqlite3_blob_close()]. 6493** 6494** See also: [sqlite3_blob_close()], 6495** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6496** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6497*/ 6498int sqlite3_blob_open( 6499 sqlite3*, 6500 const char *zDb, 6501 const char *zTable, 6502 const char *zColumn, 6503 sqlite3_int64 iRow, 6504 int flags, 6505 sqlite3_blob **ppBlob 6506); 6507 6508/* 6509** CAPI3REF: Move a BLOB Handle to a New Row 6510** METHOD: sqlite3_blob 6511** 6512** ^This function is used to move an existing [BLOB handle] so that it points 6513** to a different row of the same database table. ^The new row is identified 6514** by the rowid value passed as the second argument. Only the row can be 6515** changed. ^The database, table and column on which the blob handle is open 6516** remain the same. Moving an existing [BLOB handle] to a new row is 6517** faster than closing the existing handle and opening a new one. 6518** 6519** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6520** it must exist and there must be either a blob or text value stored in 6521** the nominated column.)^ ^If the new row is not present in the table, or if 6522** it does not contain a blob or text value, or if another error occurs, an 6523** SQLite error code is returned and the blob handle is considered aborted. 6524** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6525** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6526** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6527** always returns zero. 6528** 6529** ^This function sets the database handle error code and message. 6530*/ 6531int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6532 6533/* 6534** CAPI3REF: Close A BLOB Handle 6535** DESTRUCTOR: sqlite3_blob 6536** 6537** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6538** unconditionally. Even if this routine returns an error code, the 6539** handle is still closed.)^ 6540** 6541** ^If the blob handle being closed was opened for read-write access, and if 6542** the database is in auto-commit mode and there are no other open read-write 6543** blob handles or active write statements, the current transaction is 6544** committed. ^If an error occurs while committing the transaction, an error 6545** code is returned and the transaction rolled back. 6546** 6547** Calling this function with an argument that is not a NULL pointer or an 6548** open blob handle results in undefined behaviour. ^Calling this routine 6549** with a null pointer (such as would be returned by a failed call to 6550** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6551** is passed a valid open blob handle, the values returned by the 6552** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6553*/ 6554int sqlite3_blob_close(sqlite3_blob *); 6555 6556/* 6557** CAPI3REF: Return The Size Of An Open BLOB 6558** METHOD: sqlite3_blob 6559** 6560** ^Returns the size in bytes of the BLOB accessible via the 6561** successfully opened [BLOB handle] in its only argument. ^The 6562** incremental blob I/O routines can only read or overwriting existing 6563** blob content; they cannot change the size of a blob. 6564** 6565** This routine only works on a [BLOB handle] which has been created 6566** by a prior successful call to [sqlite3_blob_open()] and which has not 6567** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6568** to this routine results in undefined and probably undesirable behavior. 6569*/ 6570int sqlite3_blob_bytes(sqlite3_blob *); 6571 6572/* 6573** CAPI3REF: Read Data From A BLOB Incrementally 6574** METHOD: sqlite3_blob 6575** 6576** ^(This function is used to read data from an open [BLOB handle] into a 6577** caller-supplied buffer. N bytes of data are copied into buffer Z 6578** from the open BLOB, starting at offset iOffset.)^ 6579** 6580** ^If offset iOffset is less than N bytes from the end of the BLOB, 6581** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6582** less than zero, [SQLITE_ERROR] is returned and no data is read. 6583** ^The size of the blob (and hence the maximum value of N+iOffset) 6584** can be determined using the [sqlite3_blob_bytes()] interface. 6585** 6586** ^An attempt to read from an expired [BLOB handle] fails with an 6587** error code of [SQLITE_ABORT]. 6588** 6589** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6590** Otherwise, an [error code] or an [extended error code] is returned.)^ 6591** 6592** This routine only works on a [BLOB handle] which has been created 6593** by a prior successful call to [sqlite3_blob_open()] and which has not 6594** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6595** to this routine results in undefined and probably undesirable behavior. 6596** 6597** See also: [sqlite3_blob_write()]. 6598*/ 6599int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6600 6601/* 6602** CAPI3REF: Write Data Into A BLOB Incrementally 6603** METHOD: sqlite3_blob 6604** 6605** ^(This function is used to write data into an open [BLOB handle] from a 6606** caller-supplied buffer. N bytes of data are copied from the buffer Z 6607** into the open BLOB, starting at offset iOffset.)^ 6608** 6609** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6610** Otherwise, an [error code] or an [extended error code] is returned.)^ 6611** ^Unless SQLITE_MISUSE is returned, this function sets the 6612** [database connection] error code and message accessible via 6613** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6614** 6615** ^If the [BLOB handle] passed as the first argument was not opened for 6616** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6617** this function returns [SQLITE_READONLY]. 6618** 6619** This function may only modify the contents of the BLOB; it is 6620** not possible to increase the size of a BLOB using this API. 6621** ^If offset iOffset is less than N bytes from the end of the BLOB, 6622** [SQLITE_ERROR] is returned and no data is written. The size of the 6623** BLOB (and hence the maximum value of N+iOffset) can be determined 6624** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6625** than zero [SQLITE_ERROR] is returned and no data is written. 6626** 6627** ^An attempt to write to an expired [BLOB handle] fails with an 6628** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6629** before the [BLOB handle] expired are not rolled back by the 6630** expiration of the handle, though of course those changes might 6631** have been overwritten by the statement that expired the BLOB handle 6632** or by other independent statements. 6633** 6634** This routine only works on a [BLOB handle] which has been created 6635** by a prior successful call to [sqlite3_blob_open()] and which has not 6636** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6637** to this routine results in undefined and probably undesirable behavior. 6638** 6639** See also: [sqlite3_blob_read()]. 6640*/ 6641int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6642 6643/* 6644** CAPI3REF: Virtual File System Objects 6645** 6646** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6647** that SQLite uses to interact 6648** with the underlying operating system. Most SQLite builds come with a 6649** single default VFS that is appropriate for the host computer. 6650** New VFSes can be registered and existing VFSes can be unregistered. 6651** The following interfaces are provided. 6652** 6653** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6654** ^Names are case sensitive. 6655** ^Names are zero-terminated UTF-8 strings. 6656** ^If there is no match, a NULL pointer is returned. 6657** ^If zVfsName is NULL then the default VFS is returned. 6658** 6659** ^New VFSes are registered with sqlite3_vfs_register(). 6660** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6661** ^The same VFS can be registered multiple times without injury. 6662** ^To make an existing VFS into the default VFS, register it again 6663** with the makeDflt flag set. If two different VFSes with the 6664** same name are registered, the behavior is undefined. If a 6665** VFS is registered with a name that is NULL or an empty string, 6666** then the behavior is undefined. 6667** 6668** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6669** ^(If the default VFS is unregistered, another VFS is chosen as 6670** the default. The choice for the new VFS is arbitrary.)^ 6671*/ 6672sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6673int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6674int sqlite3_vfs_unregister(sqlite3_vfs*); 6675 6676/* 6677** CAPI3REF: Mutexes 6678** 6679** The SQLite core uses these routines for thread 6680** synchronization. Though they are intended for internal 6681** use by SQLite, code that links against SQLite is 6682** permitted to use any of these routines. 6683** 6684** The SQLite source code contains multiple implementations 6685** of these mutex routines. An appropriate implementation 6686** is selected automatically at compile-time. The following 6687** implementations are available in the SQLite core: 6688** 6689** <ul> 6690** <li> SQLITE_MUTEX_PTHREADS 6691** <li> SQLITE_MUTEX_W32 6692** <li> SQLITE_MUTEX_NOOP 6693** </ul> 6694** 6695** The SQLITE_MUTEX_NOOP implementation is a set of routines 6696** that does no real locking and is appropriate for use in 6697** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6698** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6699** and Windows. 6700** 6701** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6702** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6703** implementation is included with the library. In this case the 6704** application must supply a custom mutex implementation using the 6705** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6706** before calling sqlite3_initialize() or any other public sqlite3_ 6707** function that calls sqlite3_initialize(). 6708** 6709** ^The sqlite3_mutex_alloc() routine allocates a new 6710** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6711** routine returns NULL if it is unable to allocate the requested 6712** mutex. The argument to sqlite3_mutex_alloc() must one of these 6713** integer constants: 6714** 6715** <ul> 6716** <li> SQLITE_MUTEX_FAST 6717** <li> SQLITE_MUTEX_RECURSIVE 6718** <li> SQLITE_MUTEX_STATIC_MASTER 6719** <li> SQLITE_MUTEX_STATIC_MEM 6720** <li> SQLITE_MUTEX_STATIC_OPEN 6721** <li> SQLITE_MUTEX_STATIC_PRNG 6722** <li> SQLITE_MUTEX_STATIC_LRU 6723** <li> SQLITE_MUTEX_STATIC_PMEM 6724** <li> SQLITE_MUTEX_STATIC_APP1 6725** <li> SQLITE_MUTEX_STATIC_APP2 6726** <li> SQLITE_MUTEX_STATIC_APP3 6727** <li> SQLITE_MUTEX_STATIC_VFS1 6728** <li> SQLITE_MUTEX_STATIC_VFS2 6729** <li> SQLITE_MUTEX_STATIC_VFS3 6730** </ul> 6731** 6732** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6733** cause sqlite3_mutex_alloc() to create 6734** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6735** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6736** The mutex implementation does not need to make a distinction 6737** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6738** not want to. SQLite will only request a recursive mutex in 6739** cases where it really needs one. If a faster non-recursive mutex 6740** implementation is available on the host platform, the mutex subsystem 6741** might return such a mutex in response to SQLITE_MUTEX_FAST. 6742** 6743** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6744** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6745** a pointer to a static preexisting mutex. ^Nine static mutexes are 6746** used by the current version of SQLite. Future versions of SQLite 6747** may add additional static mutexes. Static mutexes are for internal 6748** use by SQLite only. Applications that use SQLite mutexes should 6749** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6750** SQLITE_MUTEX_RECURSIVE. 6751** 6752** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6753** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6754** returns a different mutex on every call. ^For the static 6755** mutex types, the same mutex is returned on every call that has 6756** the same type number. 6757** 6758** ^The sqlite3_mutex_free() routine deallocates a previously 6759** allocated dynamic mutex. Attempting to deallocate a static 6760** mutex results in undefined behavior. 6761** 6762** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6763** to enter a mutex. ^If another thread is already within the mutex, 6764** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6765** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6766** upon successful entry. ^(Mutexes created using 6767** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6768** In such cases, the 6769** mutex must be exited an equal number of times before another thread 6770** can enter.)^ If the same thread tries to enter any mutex other 6771** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6772** 6773** ^(Some systems (for example, Windows 95) do not support the operation 6774** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6775** will always return SQLITE_BUSY. The SQLite core only ever uses 6776** sqlite3_mutex_try() as an optimization so this is acceptable 6777** behavior.)^ 6778** 6779** ^The sqlite3_mutex_leave() routine exits a mutex that was 6780** previously entered by the same thread. The behavior 6781** is undefined if the mutex is not currently entered by the 6782** calling thread or is not currently allocated. 6783** 6784** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6785** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6786** behave as no-ops. 6787** 6788** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6789*/ 6790sqlite3_mutex *sqlite3_mutex_alloc(int); 6791void sqlite3_mutex_free(sqlite3_mutex*); 6792void sqlite3_mutex_enter(sqlite3_mutex*); 6793int sqlite3_mutex_try(sqlite3_mutex*); 6794void sqlite3_mutex_leave(sqlite3_mutex*); 6795 6796/* 6797** CAPI3REF: Mutex Methods Object 6798** 6799** An instance of this structure defines the low-level routines 6800** used to allocate and use mutexes. 6801** 6802** Usually, the default mutex implementations provided by SQLite are 6803** sufficient, however the application has the option of substituting a custom 6804** implementation for specialized deployments or systems for which SQLite 6805** does not provide a suitable implementation. In this case, the application 6806** creates and populates an instance of this structure to pass 6807** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6808** Additionally, an instance of this structure can be used as an 6809** output variable when querying the system for the current mutex 6810** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6811** 6812** ^The xMutexInit method defined by this structure is invoked as 6813** part of system initialization by the sqlite3_initialize() function. 6814** ^The xMutexInit routine is called by SQLite exactly once for each 6815** effective call to [sqlite3_initialize()]. 6816** 6817** ^The xMutexEnd method defined by this structure is invoked as 6818** part of system shutdown by the sqlite3_shutdown() function. The 6819** implementation of this method is expected to release all outstanding 6820** resources obtained by the mutex methods implementation, especially 6821** those obtained by the xMutexInit method. ^The xMutexEnd() 6822** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6823** 6824** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6825** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6826** xMutexNotheld) implement the following interfaces (respectively): 6827** 6828** <ul> 6829** <li> [sqlite3_mutex_alloc()] </li> 6830** <li> [sqlite3_mutex_free()] </li> 6831** <li> [sqlite3_mutex_enter()] </li> 6832** <li> [sqlite3_mutex_try()] </li> 6833** <li> [sqlite3_mutex_leave()] </li> 6834** <li> [sqlite3_mutex_held()] </li> 6835** <li> [sqlite3_mutex_notheld()] </li> 6836** </ul>)^ 6837** 6838** The only difference is that the public sqlite3_XXX functions enumerated 6839** above silently ignore any invocations that pass a NULL pointer instead 6840** of a valid mutex handle. The implementations of the methods defined 6841** by this structure are not required to handle this case, the results 6842** of passing a NULL pointer instead of a valid mutex handle are undefined 6843** (i.e. it is acceptable to provide an implementation that segfaults if 6844** it is passed a NULL pointer). 6845** 6846** The xMutexInit() method must be threadsafe. It must be harmless to 6847** invoke xMutexInit() multiple times within the same process and without 6848** intervening calls to xMutexEnd(). Second and subsequent calls to 6849** xMutexInit() must be no-ops. 6850** 6851** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6852** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6853** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6854** memory allocation for a fast or recursive mutex. 6855** 6856** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6857** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6858** If xMutexInit fails in any way, it is expected to clean up after itself 6859** prior to returning. 6860*/ 6861typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6862struct sqlite3_mutex_methods { 6863 int (*xMutexInit)(void); 6864 int (*xMutexEnd)(void); 6865 sqlite3_mutex *(*xMutexAlloc)(int); 6866 void (*xMutexFree)(sqlite3_mutex *); 6867 void (*xMutexEnter)(sqlite3_mutex *); 6868 int (*xMutexTry)(sqlite3_mutex *); 6869 void (*xMutexLeave)(sqlite3_mutex *); 6870 int (*xMutexHeld)(sqlite3_mutex *); 6871 int (*xMutexNotheld)(sqlite3_mutex *); 6872}; 6873 6874/* 6875** CAPI3REF: Mutex Verification Routines 6876** 6877** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6878** are intended for use inside assert() statements. The SQLite core 6879** never uses these routines except inside an assert() and applications 6880** are advised to follow the lead of the core. The SQLite core only 6881** provides implementations for these routines when it is compiled 6882** with the SQLITE_DEBUG flag. External mutex implementations 6883** are only required to provide these routines if SQLITE_DEBUG is 6884** defined and if NDEBUG is not defined. 6885** 6886** These routines should return true if the mutex in their argument 6887** is held or not held, respectively, by the calling thread. 6888** 6889** The implementation is not required to provide versions of these 6890** routines that actually work. If the implementation does not provide working 6891** versions of these routines, it should at least provide stubs that always 6892** return true so that one does not get spurious assertion failures. 6893** 6894** If the argument to sqlite3_mutex_held() is a NULL pointer then 6895** the routine should return 1. This seems counter-intuitive since 6896** clearly the mutex cannot be held if it does not exist. But 6897** the reason the mutex does not exist is because the build is not 6898** using mutexes. And we do not want the assert() containing the 6899** call to sqlite3_mutex_held() to fail, so a non-zero return is 6900** the appropriate thing to do. The sqlite3_mutex_notheld() 6901** interface should also return 1 when given a NULL pointer. 6902*/ 6903#ifndef NDEBUG 6904int sqlite3_mutex_held(sqlite3_mutex*); 6905int sqlite3_mutex_notheld(sqlite3_mutex*); 6906#endif 6907 6908/* 6909** CAPI3REF: Mutex Types 6910** 6911** The [sqlite3_mutex_alloc()] interface takes a single argument 6912** which is one of these integer constants. 6913** 6914** The set of static mutexes may change from one SQLite release to the 6915** next. Applications that override the built-in mutex logic must be 6916** prepared to accommodate additional static mutexes. 6917*/ 6918#define SQLITE_MUTEX_FAST 0 6919#define SQLITE_MUTEX_RECURSIVE 1 6920#define SQLITE_MUTEX_STATIC_MASTER 2 6921#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6922#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6923#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6924#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6925#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6926#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6927#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6928#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6929#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6930#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6931#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6932#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6933#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6934 6935/* 6936** CAPI3REF: Retrieve the mutex for a database connection 6937** METHOD: sqlite3 6938** 6939** ^This interface returns a pointer the [sqlite3_mutex] object that 6940** serializes access to the [database connection] given in the argument 6941** when the [threading mode] is Serialized. 6942** ^If the [threading mode] is Single-thread or Multi-thread then this 6943** routine returns a NULL pointer. 6944*/ 6945sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6946 6947/* 6948** CAPI3REF: Low-Level Control Of Database Files 6949** METHOD: sqlite3 6950** 6951** ^The [sqlite3_file_control()] interface makes a direct call to the 6952** xFileControl method for the [sqlite3_io_methods] object associated 6953** with a particular database identified by the second argument. ^The 6954** name of the database is "main" for the main database or "temp" for the 6955** TEMP database, or the name that appears after the AS keyword for 6956** databases that are added using the [ATTACH] SQL command. 6957** ^A NULL pointer can be used in place of "main" to refer to the 6958** main database file. 6959** ^The third and fourth parameters to this routine 6960** are passed directly through to the second and third parameters of 6961** the xFileControl method. ^The return value of the xFileControl 6962** method becomes the return value of this routine. 6963** 6964** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 6965** a pointer to the underlying [sqlite3_file] object to be written into 6966** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 6967** case is a short-circuit path which does not actually invoke the 6968** underlying sqlite3_io_methods.xFileControl method. 6969** 6970** ^If the second parameter (zDbName) does not match the name of any 6971** open database file, then SQLITE_ERROR is returned. ^This error 6972** code is not remembered and will not be recalled by [sqlite3_errcode()] 6973** or [sqlite3_errmsg()]. The underlying xFileControl method might 6974** also return SQLITE_ERROR. There is no way to distinguish between 6975** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6976** xFileControl method. 6977** 6978** See also: [SQLITE_FCNTL_LOCKSTATE] 6979*/ 6980int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6981 6982/* 6983** CAPI3REF: Testing Interface 6984** 6985** ^The sqlite3_test_control() interface is used to read out internal 6986** state of SQLite and to inject faults into SQLite for testing 6987** purposes. ^The first parameter is an operation code that determines 6988** the number, meaning, and operation of all subsequent parameters. 6989** 6990** This interface is not for use by applications. It exists solely 6991** for verifying the correct operation of the SQLite library. Depending 6992** on how the SQLite library is compiled, this interface might not exist. 6993** 6994** The details of the operation codes, their meanings, the parameters 6995** they take, and what they do are all subject to change without notice. 6996** Unlike most of the SQLite API, this function is not guaranteed to 6997** operate consistently from one release to the next. 6998*/ 6999int sqlite3_test_control(int op, ...); 7000 7001/* 7002** CAPI3REF: Testing Interface Operation Codes 7003** 7004** These constants are the valid operation code parameters used 7005** as the first argument to [sqlite3_test_control()]. 7006** 7007** These parameters and their meanings are subject to change 7008** without notice. These values are for testing purposes only. 7009** Applications should not use any of these parameters or the 7010** [sqlite3_test_control()] interface. 7011*/ 7012#define SQLITE_TESTCTRL_FIRST 5 7013#define SQLITE_TESTCTRL_PRNG_SAVE 5 7014#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7015#define SQLITE_TESTCTRL_PRNG_RESET 7 7016#define SQLITE_TESTCTRL_BITVEC_TEST 8 7017#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7018#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7019#define SQLITE_TESTCTRL_PENDING_BYTE 11 7020#define SQLITE_TESTCTRL_ASSERT 12 7021#define SQLITE_TESTCTRL_ALWAYS 13 7022#define SQLITE_TESTCTRL_RESERVE 14 7023#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7024#define SQLITE_TESTCTRL_ISKEYWORD 16 7025#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7026#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7027#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7028#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7029#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7030#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7031#define SQLITE_TESTCTRL_BYTEORDER 22 7032#define SQLITE_TESTCTRL_ISINIT 23 7033#define SQLITE_TESTCTRL_SORTER_MMAP 24 7034#define SQLITE_TESTCTRL_IMPOSTER 25 7035#define SQLITE_TESTCTRL_LAST 25 7036 7037/* 7038** CAPI3REF: SQLite Runtime Status 7039** 7040** ^These interfaces are used to retrieve runtime status information 7041** about the performance of SQLite, and optionally to reset various 7042** highwater marks. ^The first argument is an integer code for 7043** the specific parameter to measure. ^(Recognized integer codes 7044** are of the form [status parameters | SQLITE_STATUS_...].)^ 7045** ^The current value of the parameter is returned into *pCurrent. 7046** ^The highest recorded value is returned in *pHighwater. ^If the 7047** resetFlag is true, then the highest record value is reset after 7048** *pHighwater is written. ^(Some parameters do not record the highest 7049** value. For those parameters 7050** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7051** ^(Other parameters record only the highwater mark and not the current 7052** value. For these latter parameters nothing is written into *pCurrent.)^ 7053** 7054** ^The sqlite3_status() and sqlite3_status64() routines return 7055** SQLITE_OK on success and a non-zero [error code] on failure. 7056** 7057** If either the current value or the highwater mark is too large to 7058** be represented by a 32-bit integer, then the values returned by 7059** sqlite3_status() are undefined. 7060** 7061** See also: [sqlite3_db_status()] 7062*/ 7063int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7064int sqlite3_status64( 7065 int op, 7066 sqlite3_int64 *pCurrent, 7067 sqlite3_int64 *pHighwater, 7068 int resetFlag 7069); 7070 7071 7072/* 7073** CAPI3REF: Status Parameters 7074** KEYWORDS: {status parameters} 7075** 7076** These integer constants designate various run-time status parameters 7077** that can be returned by [sqlite3_status()]. 7078** 7079** <dl> 7080** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7081** <dd>This parameter is the current amount of memory checked out 7082** using [sqlite3_malloc()], either directly or indirectly. The 7083** figure includes calls made to [sqlite3_malloc()] by the application 7084** and internal memory usage by the SQLite library. Auxiliary page-cache 7085** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7086** this parameter. The amount returned is the sum of the allocation 7087** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7088** 7089** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7090** <dd>This parameter records the largest memory allocation request 7091** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7092** internal equivalents). Only the value returned in the 7093** *pHighwater parameter to [sqlite3_status()] is of interest. 7094** The value written into the *pCurrent parameter is undefined.</dd>)^ 7095** 7096** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7097** <dd>This parameter records the number of separate memory allocations 7098** currently checked out.</dd>)^ 7099** 7100** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7101** <dd>This parameter returns the number of pages used out of the 7102** [pagecache memory allocator] that was configured using 7103** [SQLITE_CONFIG_PAGECACHE]. The 7104** value returned is in pages, not in bytes.</dd>)^ 7105** 7106** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7107** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7108** <dd>This parameter returns the number of bytes of page cache 7109** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7110** buffer and where forced to overflow to [sqlite3_malloc()]. The 7111** returned value includes allocations that overflowed because they 7112** where too large (they were larger than the "sz" parameter to 7113** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7114** no space was left in the page cache.</dd>)^ 7115** 7116** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7117** <dd>This parameter records the largest memory allocation request 7118** handed to [pagecache memory allocator]. Only the value returned in the 7119** *pHighwater parameter to [sqlite3_status()] is of interest. 7120** The value written into the *pCurrent parameter is undefined.</dd>)^ 7121** 7122** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7123** <dd>No longer used.</dd> 7124** 7125** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7126** <dd>No longer used.</dd> 7127** 7128** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7129** <dd>No longer used.</dd> 7130** 7131** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7132** <dd>The *pHighwater parameter records the deepest parser stack. 7133** The *pCurrent value is undefined. The *pHighwater value is only 7134** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7135** </dl> 7136** 7137** New status parameters may be added from time to time. 7138*/ 7139#define SQLITE_STATUS_MEMORY_USED 0 7140#define SQLITE_STATUS_PAGECACHE_USED 1 7141#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7142#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7143#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7144#define SQLITE_STATUS_MALLOC_SIZE 5 7145#define SQLITE_STATUS_PARSER_STACK 6 7146#define SQLITE_STATUS_PAGECACHE_SIZE 7 7147#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7148#define SQLITE_STATUS_MALLOC_COUNT 9 7149 7150/* 7151** CAPI3REF: Database Connection Status 7152** METHOD: sqlite3 7153** 7154** ^This interface is used to retrieve runtime status information 7155** about a single [database connection]. ^The first argument is the 7156** database connection object to be interrogated. ^The second argument 7157** is an integer constant, taken from the set of 7158** [SQLITE_DBSTATUS options], that 7159** determines the parameter to interrogate. The set of 7160** [SQLITE_DBSTATUS options] is likely 7161** to grow in future releases of SQLite. 7162** 7163** ^The current value of the requested parameter is written into *pCur 7164** and the highest instantaneous value is written into *pHiwtr. ^If 7165** the resetFlg is true, then the highest instantaneous value is 7166** reset back down to the current value. 7167** 7168** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7169** non-zero [error code] on failure. 7170** 7171** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7172*/ 7173int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7174 7175/* 7176** CAPI3REF: Status Parameters for database connections 7177** KEYWORDS: {SQLITE_DBSTATUS options} 7178** 7179** These constants are the available integer "verbs" that can be passed as 7180** the second argument to the [sqlite3_db_status()] interface. 7181** 7182** New verbs may be added in future releases of SQLite. Existing verbs 7183** might be discontinued. Applications should check the return code from 7184** [sqlite3_db_status()] to make sure that the call worked. 7185** The [sqlite3_db_status()] interface will return a non-zero error code 7186** if a discontinued or unsupported verb is invoked. 7187** 7188** <dl> 7189** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7190** <dd>This parameter returns the number of lookaside memory slots currently 7191** checked out.</dd>)^ 7192** 7193** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7194** <dd>This parameter returns the number malloc attempts that were 7195** satisfied using lookaside memory. Only the high-water value is meaningful; 7196** the current value is always zero.)^ 7197** 7198** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7199** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7200** <dd>This parameter returns the number malloc attempts that might have 7201** been satisfied using lookaside memory but failed due to the amount of 7202** memory requested being larger than the lookaside slot size. 7203** Only the high-water value is meaningful; 7204** the current value is always zero.)^ 7205** 7206** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7207** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7208** <dd>This parameter returns the number malloc attempts that might have 7209** been satisfied using lookaside memory but failed due to all lookaside 7210** memory already being in use. 7211** Only the high-water value is meaningful; 7212** the current value is always zero.)^ 7213** 7214** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7215** <dd>This parameter returns the approximate number of bytes of heap 7216** memory used by all pager caches associated with the database connection.)^ 7217** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7218** 7219** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7220** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7221** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7222** pager cache is shared between two or more connections the bytes of heap 7223** memory used by that pager cache is divided evenly between the attached 7224** connections.)^ In other words, if none of the pager caches associated 7225** with the database connection are shared, this request returns the same 7226** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7227** shared, the value returned by this call will be smaller than that returned 7228** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7229** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7230** 7231** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7232** <dd>This parameter returns the approximate number of bytes of heap 7233** memory used to store the schema for all databases associated 7234** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7235** ^The full amount of memory used by the schemas is reported, even if the 7236** schema memory is shared with other database connections due to 7237** [shared cache mode] being enabled. 7238** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7239** 7240** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7241** <dd>This parameter returns the approximate number of bytes of heap 7242** and lookaside memory used by all prepared statements associated with 7243** the database connection.)^ 7244** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7245** </dd> 7246** 7247** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7248** <dd>This parameter returns the number of pager cache hits that have 7249** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7250** is always 0. 7251** </dd> 7252** 7253** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7254** <dd>This parameter returns the number of pager cache misses that have 7255** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7256** is always 0. 7257** </dd> 7258** 7259** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7260** <dd>This parameter returns the number of dirty cache entries that have 7261** been written to disk. Specifically, the number of pages written to the 7262** wal file in wal mode databases, or the number of pages written to the 7263** database file in rollback mode databases. Any pages written as part of 7264** transaction rollback or database recovery operations are not included. 7265** If an IO or other error occurs while writing a page to disk, the effect 7266** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7267** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7268** </dd> 7269** 7270** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7271** <dd>This parameter returns zero for the current value if and only if 7272** all foreign key constraints (deferred or immediate) have been 7273** resolved.)^ ^The highwater mark is always 0. 7274** </dd> 7275** </dl> 7276*/ 7277#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7278#define SQLITE_DBSTATUS_CACHE_USED 1 7279#define SQLITE_DBSTATUS_SCHEMA_USED 2 7280#define SQLITE_DBSTATUS_STMT_USED 3 7281#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7282#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7283#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7284#define SQLITE_DBSTATUS_CACHE_HIT 7 7285#define SQLITE_DBSTATUS_CACHE_MISS 8 7286#define SQLITE_DBSTATUS_CACHE_WRITE 9 7287#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7288#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7289#define SQLITE_DBSTATUS_MAX 11 /* Largest defined DBSTATUS */ 7290 7291 7292/* 7293** CAPI3REF: Prepared Statement Status 7294** METHOD: sqlite3_stmt 7295** 7296** ^(Each prepared statement maintains various 7297** [SQLITE_STMTSTATUS counters] that measure the number 7298** of times it has performed specific operations.)^ These counters can 7299** be used to monitor the performance characteristics of the prepared 7300** statements. For example, if the number of table steps greatly exceeds 7301** the number of table searches or result rows, that would tend to indicate 7302** that the prepared statement is using a full table scan rather than 7303** an index. 7304** 7305** ^(This interface is used to retrieve and reset counter values from 7306** a [prepared statement]. The first argument is the prepared statement 7307** object to be interrogated. The second argument 7308** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7309** to be interrogated.)^ 7310** ^The current value of the requested counter is returned. 7311** ^If the resetFlg is true, then the counter is reset to zero after this 7312** interface call returns. 7313** 7314** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7315*/ 7316int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7317 7318/* 7319** CAPI3REF: Status Parameters for prepared statements 7320** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7321** 7322** These preprocessor macros define integer codes that name counter 7323** values associated with the [sqlite3_stmt_status()] interface. 7324** The meanings of the various counters are as follows: 7325** 7326** <dl> 7327** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7328** <dd>^This is the number of times that SQLite has stepped forward in 7329** a table as part of a full table scan. Large numbers for this counter 7330** may indicate opportunities for performance improvement through 7331** careful use of indices.</dd> 7332** 7333** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7334** <dd>^This is the number of sort operations that have occurred. 7335** A non-zero value in this counter may indicate an opportunity to 7336** improvement performance through careful use of indices.</dd> 7337** 7338** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7339** <dd>^This is the number of rows inserted into transient indices that 7340** were created automatically in order to help joins run faster. 7341** A non-zero value in this counter may indicate an opportunity to 7342** improvement performance by adding permanent indices that do not 7343** need to be reinitialized each time the statement is run.</dd> 7344** 7345** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7346** <dd>^This is the number of virtual machine operations executed 7347** by the prepared statement if that number is less than or equal 7348** to 2147483647. The number of virtual machine operations can be 7349** used as a proxy for the total work done by the prepared statement. 7350** If the number of virtual machine operations exceeds 2147483647 7351** then the value returned by this statement status code is undefined. 7352** 7353** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7354** <dd>^This is the number of times that the prepare statement has been 7355** automatically regenerated due to schema changes or change to 7356** [bound parameters] that might affect the query plan. 7357** 7358** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7359** <dd>^This is the number of times that the prepared statement has 7360** been run. A single "run" for the purposes of this counter is one 7361** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7362** The counter is incremented on the first [sqlite3_step()] call of each 7363** cycle. 7364** 7365** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7366** <dd>^This is the approximate number of bytes of heap memory 7367** used to store the prepared statement. ^This value is not actually 7368** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7369** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7370** </dd> 7371** </dl> 7372*/ 7373#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7374#define SQLITE_STMTSTATUS_SORT 2 7375#define SQLITE_STMTSTATUS_AUTOINDEX 3 7376#define SQLITE_STMTSTATUS_VM_STEP 4 7377#define SQLITE_STMTSTATUS_REPREPARE 5 7378#define SQLITE_STMTSTATUS_RUN 6 7379#define SQLITE_STMTSTATUS_MEMUSED 99 7380 7381/* 7382** CAPI3REF: Custom Page Cache Object 7383** 7384** The sqlite3_pcache type is opaque. It is implemented by 7385** the pluggable module. The SQLite core has no knowledge of 7386** its size or internal structure and never deals with the 7387** sqlite3_pcache object except by holding and passing pointers 7388** to the object. 7389** 7390** See [sqlite3_pcache_methods2] for additional information. 7391*/ 7392typedef struct sqlite3_pcache sqlite3_pcache; 7393 7394/* 7395** CAPI3REF: Custom Page Cache Object 7396** 7397** The sqlite3_pcache_page object represents a single page in the 7398** page cache. The page cache will allocate instances of this 7399** object. Various methods of the page cache use pointers to instances 7400** of this object as parameters or as their return value. 7401** 7402** See [sqlite3_pcache_methods2] for additional information. 7403*/ 7404typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7405struct sqlite3_pcache_page { 7406 void *pBuf; /* The content of the page */ 7407 void *pExtra; /* Extra information associated with the page */ 7408}; 7409 7410/* 7411** CAPI3REF: Application Defined Page Cache. 7412** KEYWORDS: {page cache} 7413** 7414** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7415** register an alternative page cache implementation by passing in an 7416** instance of the sqlite3_pcache_methods2 structure.)^ 7417** In many applications, most of the heap memory allocated by 7418** SQLite is used for the page cache. 7419** By implementing a 7420** custom page cache using this API, an application can better control 7421** the amount of memory consumed by SQLite, the way in which 7422** that memory is allocated and released, and the policies used to 7423** determine exactly which parts of a database file are cached and for 7424** how long. 7425** 7426** The alternative page cache mechanism is an 7427** extreme measure that is only needed by the most demanding applications. 7428** The built-in page cache is recommended for most uses. 7429** 7430** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7431** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7432** the application may discard the parameter after the call to 7433** [sqlite3_config()] returns.)^ 7434** 7435** [[the xInit() page cache method]] 7436** ^(The xInit() method is called once for each effective 7437** call to [sqlite3_initialize()])^ 7438** (usually only once during the lifetime of the process). ^(The xInit() 7439** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7440** The intent of the xInit() method is to set up global data structures 7441** required by the custom page cache implementation. 7442** ^(If the xInit() method is NULL, then the 7443** built-in default page cache is used instead of the application defined 7444** page cache.)^ 7445** 7446** [[the xShutdown() page cache method]] 7447** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7448** It can be used to clean up 7449** any outstanding resources before process shutdown, if required. 7450** ^The xShutdown() method may be NULL. 7451** 7452** ^SQLite automatically serializes calls to the xInit method, 7453** so the xInit method need not be threadsafe. ^The 7454** xShutdown method is only called from [sqlite3_shutdown()] so it does 7455** not need to be threadsafe either. All other methods must be threadsafe 7456** in multithreaded applications. 7457** 7458** ^SQLite will never invoke xInit() more than once without an intervening 7459** call to xShutdown(). 7460** 7461** [[the xCreate() page cache methods]] 7462** ^SQLite invokes the xCreate() method to construct a new cache instance. 7463** SQLite will typically create one cache instance for each open database file, 7464** though this is not guaranteed. ^The 7465** first parameter, szPage, is the size in bytes of the pages that must 7466** be allocated by the cache. ^szPage will always a power of two. ^The 7467** second parameter szExtra is a number of bytes of extra storage 7468** associated with each page cache entry. ^The szExtra parameter will 7469** a number less than 250. SQLite will use the 7470** extra szExtra bytes on each page to store metadata about the underlying 7471** database page on disk. The value passed into szExtra depends 7472** on the SQLite version, the target platform, and how SQLite was compiled. 7473** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7474** created will be used to cache database pages of a file stored on disk, or 7475** false if it is used for an in-memory database. The cache implementation 7476** does not have to do anything special based with the value of bPurgeable; 7477** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7478** never invoke xUnpin() except to deliberately delete a page. 7479** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7480** false will always have the "discard" flag set to true. 7481** ^Hence, a cache created with bPurgeable false will 7482** never contain any unpinned pages. 7483** 7484** [[the xCachesize() page cache method]] 7485** ^(The xCachesize() method may be called at any time by SQLite to set the 7486** suggested maximum cache-size (number of pages stored by) the cache 7487** instance passed as the first argument. This is the value configured using 7488** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7489** parameter, the implementation is not required to do anything with this 7490** value; it is advisory only. 7491** 7492** [[the xPagecount() page cache methods]] 7493** The xPagecount() method must return the number of pages currently 7494** stored in the cache, both pinned and unpinned. 7495** 7496** [[the xFetch() page cache methods]] 7497** The xFetch() method locates a page in the cache and returns a pointer to 7498** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7499** The pBuf element of the returned sqlite3_pcache_page object will be a 7500** pointer to a buffer of szPage bytes used to store the content of a 7501** single database page. The pExtra element of sqlite3_pcache_page will be 7502** a pointer to the szExtra bytes of extra storage that SQLite has requested 7503** for each entry in the page cache. 7504** 7505** The page to be fetched is determined by the key. ^The minimum key value 7506** is 1. After it has been retrieved using xFetch, the page is considered 7507** to be "pinned". 7508** 7509** If the requested page is already in the page cache, then the page cache 7510** implementation must return a pointer to the page buffer with its content 7511** intact. If the requested page is not already in the cache, then the 7512** cache implementation should use the value of the createFlag 7513** parameter to help it determined what action to take: 7514** 7515** <table border=1 width=85% align=center> 7516** <tr><th> createFlag <th> Behavior when page is not already in cache 7517** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7518** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7519** Otherwise return NULL. 7520** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7521** NULL if allocating a new page is effectively impossible. 7522** </table> 7523** 7524** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7525** will only use a createFlag of 2 after a prior call with a createFlag of 1 7526** failed.)^ In between the to xFetch() calls, SQLite may 7527** attempt to unpin one or more cache pages by spilling the content of 7528** pinned pages to disk and synching the operating system disk cache. 7529** 7530** [[the xUnpin() page cache method]] 7531** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7532** as its second argument. If the third parameter, discard, is non-zero, 7533** then the page must be evicted from the cache. 7534** ^If the discard parameter is 7535** zero, then the page may be discarded or retained at the discretion of 7536** page cache implementation. ^The page cache implementation 7537** may choose to evict unpinned pages at any time. 7538** 7539** The cache must not perform any reference counting. A single 7540** call to xUnpin() unpins the page regardless of the number of prior calls 7541** to xFetch(). 7542** 7543** [[the xRekey() page cache methods]] 7544** The xRekey() method is used to change the key value associated with the 7545** page passed as the second argument. If the cache 7546** previously contains an entry associated with newKey, it must be 7547** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7548** to be pinned. 7549** 7550** When SQLite calls the xTruncate() method, the cache must discard all 7551** existing cache entries with page numbers (keys) greater than or equal 7552** to the value of the iLimit parameter passed to xTruncate(). If any 7553** of these pages are pinned, they are implicitly unpinned, meaning that 7554** they can be safely discarded. 7555** 7556** [[the xDestroy() page cache method]] 7557** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7558** All resources associated with the specified cache should be freed. ^After 7559** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7560** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7561** functions. 7562** 7563** [[the xShrink() page cache method]] 7564** ^SQLite invokes the xShrink() method when it wants the page cache to 7565** free up as much of heap memory as possible. The page cache implementation 7566** is not obligated to free any memory, but well-behaved implementations should 7567** do their best. 7568*/ 7569typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7570struct sqlite3_pcache_methods2 { 7571 int iVersion; 7572 void *pArg; 7573 int (*xInit)(void*); 7574 void (*xShutdown)(void*); 7575 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7576 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7577 int (*xPagecount)(sqlite3_pcache*); 7578 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7579 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7580 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7581 unsigned oldKey, unsigned newKey); 7582 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7583 void (*xDestroy)(sqlite3_pcache*); 7584 void (*xShrink)(sqlite3_pcache*); 7585}; 7586 7587/* 7588** This is the obsolete pcache_methods object that has now been replaced 7589** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7590** retained in the header file for backwards compatibility only. 7591*/ 7592typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7593struct sqlite3_pcache_methods { 7594 void *pArg; 7595 int (*xInit)(void*); 7596 void (*xShutdown)(void*); 7597 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7598 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7599 int (*xPagecount)(sqlite3_pcache*); 7600 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7601 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7602 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7603 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7604 void (*xDestroy)(sqlite3_pcache*); 7605}; 7606 7607 7608/* 7609** CAPI3REF: Online Backup Object 7610** 7611** The sqlite3_backup object records state information about an ongoing 7612** online backup operation. ^The sqlite3_backup object is created by 7613** a call to [sqlite3_backup_init()] and is destroyed by a call to 7614** [sqlite3_backup_finish()]. 7615** 7616** See Also: [Using the SQLite Online Backup API] 7617*/ 7618typedef struct sqlite3_backup sqlite3_backup; 7619 7620/* 7621** CAPI3REF: Online Backup API. 7622** 7623** The backup API copies the content of one database into another. 7624** It is useful either for creating backups of databases or 7625** for copying in-memory databases to or from persistent files. 7626** 7627** See Also: [Using the SQLite Online Backup API] 7628** 7629** ^SQLite holds a write transaction open on the destination database file 7630** for the duration of the backup operation. 7631** ^The source database is read-locked only while it is being read; 7632** it is not locked continuously for the entire backup operation. 7633** ^Thus, the backup may be performed on a live source database without 7634** preventing other database connections from 7635** reading or writing to the source database while the backup is underway. 7636** 7637** ^(To perform a backup operation: 7638** <ol> 7639** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7640** backup, 7641** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7642** the data between the two databases, and finally 7643** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7644** associated with the backup operation. 7645** </ol>)^ 7646** There should be exactly one call to sqlite3_backup_finish() for each 7647** successful call to sqlite3_backup_init(). 7648** 7649** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7650** 7651** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7652** [database connection] associated with the destination database 7653** and the database name, respectively. 7654** ^The database name is "main" for the main database, "temp" for the 7655** temporary database, or the name specified after the AS keyword in 7656** an [ATTACH] statement for an attached database. 7657** ^The S and M arguments passed to 7658** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7659** and database name of the source database, respectively. 7660** ^The source and destination [database connections] (parameters S and D) 7661** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7662** an error. 7663** 7664** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7665** there is already a read or read-write transaction open on the 7666** destination database. 7667** 7668** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7669** returned and an error code and error message are stored in the 7670** destination [database connection] D. 7671** ^The error code and message for the failed call to sqlite3_backup_init() 7672** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7673** [sqlite3_errmsg16()] functions. 7674** ^A successful call to sqlite3_backup_init() returns a pointer to an 7675** [sqlite3_backup] object. 7676** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7677** sqlite3_backup_finish() functions to perform the specified backup 7678** operation. 7679** 7680** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7681** 7682** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7683** the source and destination databases specified by [sqlite3_backup] object B. 7684** ^If N is negative, all remaining source pages are copied. 7685** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7686** are still more pages to be copied, then the function returns [SQLITE_OK]. 7687** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7688** from source to destination, then it returns [SQLITE_DONE]. 7689** ^If an error occurs while running sqlite3_backup_step(B,N), 7690** then an [error code] is returned. ^As well as [SQLITE_OK] and 7691** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7692** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7693** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7694** 7695** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7696** <ol> 7697** <li> the destination database was opened read-only, or 7698** <li> the destination database is using write-ahead-log journaling 7699** and the destination and source page sizes differ, or 7700** <li> the destination database is an in-memory database and the 7701** destination and source page sizes differ. 7702** </ol>)^ 7703** 7704** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7705** the [sqlite3_busy_handler | busy-handler function] 7706** is invoked (if one is specified). ^If the 7707** busy-handler returns non-zero before the lock is available, then 7708** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7709** sqlite3_backup_step() can be retried later. ^If the source 7710** [database connection] 7711** is being used to write to the source database when sqlite3_backup_step() 7712** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7713** case the call to sqlite3_backup_step() can be retried later on. ^(If 7714** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7715** [SQLITE_READONLY] is returned, then 7716** there is no point in retrying the call to sqlite3_backup_step(). These 7717** errors are considered fatal.)^ The application must accept 7718** that the backup operation has failed and pass the backup operation handle 7719** to the sqlite3_backup_finish() to release associated resources. 7720** 7721** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7722** on the destination file. ^The exclusive lock is not released until either 7723** sqlite3_backup_finish() is called or the backup operation is complete 7724** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7725** sqlite3_backup_step() obtains a [shared lock] on the source database that 7726** lasts for the duration of the sqlite3_backup_step() call. 7727** ^Because the source database is not locked between calls to 7728** sqlite3_backup_step(), the source database may be modified mid-way 7729** through the backup process. ^If the source database is modified by an 7730** external process or via a database connection other than the one being 7731** used by the backup operation, then the backup will be automatically 7732** restarted by the next call to sqlite3_backup_step(). ^If the source 7733** database is modified by the using the same database connection as is used 7734** by the backup operation, then the backup database is automatically 7735** updated at the same time. 7736** 7737** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7738** 7739** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7740** application wishes to abandon the backup operation, the application 7741** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7742** ^The sqlite3_backup_finish() interfaces releases all 7743** resources associated with the [sqlite3_backup] object. 7744** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7745** active write-transaction on the destination database is rolled back. 7746** The [sqlite3_backup] object is invalid 7747** and may not be used following a call to sqlite3_backup_finish(). 7748** 7749** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7750** sqlite3_backup_step() errors occurred, regardless or whether or not 7751** sqlite3_backup_step() completed. 7752** ^If an out-of-memory condition or IO error occurred during any prior 7753** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7754** sqlite3_backup_finish() returns the corresponding [error code]. 7755** 7756** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7757** is not a permanent error and does not affect the return value of 7758** sqlite3_backup_finish(). 7759** 7760** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7761** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7762** 7763** ^The sqlite3_backup_remaining() routine returns the number of pages still 7764** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7765** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7766** in the source database at the conclusion of the most recent 7767** sqlite3_backup_step(). 7768** ^(The values returned by these functions are only updated by 7769** sqlite3_backup_step(). If the source database is modified in a way that 7770** changes the size of the source database or the number of pages remaining, 7771** those changes are not reflected in the output of sqlite3_backup_pagecount() 7772** and sqlite3_backup_remaining() until after the next 7773** sqlite3_backup_step().)^ 7774** 7775** <b>Concurrent Usage of Database Handles</b> 7776** 7777** ^The source [database connection] may be used by the application for other 7778** purposes while a backup operation is underway or being initialized. 7779** ^If SQLite is compiled and configured to support threadsafe database 7780** connections, then the source database connection may be used concurrently 7781** from within other threads. 7782** 7783** However, the application must guarantee that the destination 7784** [database connection] is not passed to any other API (by any thread) after 7785** sqlite3_backup_init() is called and before the corresponding call to 7786** sqlite3_backup_finish(). SQLite does not currently check to see 7787** if the application incorrectly accesses the destination [database connection] 7788** and so no error code is reported, but the operations may malfunction 7789** nevertheless. Use of the destination database connection while a 7790** backup is in progress might also also cause a mutex deadlock. 7791** 7792** If running in [shared cache mode], the application must 7793** guarantee that the shared cache used by the destination database 7794** is not accessed while the backup is running. In practice this means 7795** that the application must guarantee that the disk file being 7796** backed up to is not accessed by any connection within the process, 7797** not just the specific connection that was passed to sqlite3_backup_init(). 7798** 7799** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7800** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7801** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7802** APIs are not strictly speaking threadsafe. If they are invoked at the 7803** same time as another thread is invoking sqlite3_backup_step() it is 7804** possible that they return invalid values. 7805*/ 7806sqlite3_backup *sqlite3_backup_init( 7807 sqlite3 *pDest, /* Destination database handle */ 7808 const char *zDestName, /* Destination database name */ 7809 sqlite3 *pSource, /* Source database handle */ 7810 const char *zSourceName /* Source database name */ 7811); 7812int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7813int sqlite3_backup_finish(sqlite3_backup *p); 7814int sqlite3_backup_remaining(sqlite3_backup *p); 7815int sqlite3_backup_pagecount(sqlite3_backup *p); 7816 7817/* 7818** CAPI3REF: Unlock Notification 7819** METHOD: sqlite3 7820** 7821** ^When running in shared-cache mode, a database operation may fail with 7822** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7823** individual tables within the shared-cache cannot be obtained. See 7824** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7825** ^This API may be used to register a callback that SQLite will invoke 7826** when the connection currently holding the required lock relinquishes it. 7827** ^This API is only available if the library was compiled with the 7828** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7829** 7830** See Also: [Using the SQLite Unlock Notification Feature]. 7831** 7832** ^Shared-cache locks are released when a database connection concludes 7833** its current transaction, either by committing it or rolling it back. 7834** 7835** ^When a connection (known as the blocked connection) fails to obtain a 7836** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7837** identity of the database connection (the blocking connection) that 7838** has locked the required resource is stored internally. ^After an 7839** application receives an SQLITE_LOCKED error, it may call the 7840** sqlite3_unlock_notify() method with the blocked connection handle as 7841** the first argument to register for a callback that will be invoked 7842** when the blocking connections current transaction is concluded. ^The 7843** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7844** call that concludes the blocking connections transaction. 7845** 7846** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7847** there is a chance that the blocking connection will have already 7848** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7849** If this happens, then the specified callback is invoked immediately, 7850** from within the call to sqlite3_unlock_notify().)^ 7851** 7852** ^If the blocked connection is attempting to obtain a write-lock on a 7853** shared-cache table, and more than one other connection currently holds 7854** a read-lock on the same table, then SQLite arbitrarily selects one of 7855** the other connections to use as the blocking connection. 7856** 7857** ^(There may be at most one unlock-notify callback registered by a 7858** blocked connection. If sqlite3_unlock_notify() is called when the 7859** blocked connection already has a registered unlock-notify callback, 7860** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7861** called with a NULL pointer as its second argument, then any existing 7862** unlock-notify callback is canceled. ^The blocked connections 7863** unlock-notify callback may also be canceled by closing the blocked 7864** connection using [sqlite3_close()]. 7865** 7866** The unlock-notify callback is not reentrant. If an application invokes 7867** any sqlite3_xxx API functions from within an unlock-notify callback, a 7868** crash or deadlock may be the result. 7869** 7870** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7871** returns SQLITE_OK. 7872** 7873** <b>Callback Invocation Details</b> 7874** 7875** When an unlock-notify callback is registered, the application provides a 7876** single void* pointer that is passed to the callback when it is invoked. 7877** However, the signature of the callback function allows SQLite to pass 7878** it an array of void* context pointers. The first argument passed to 7879** an unlock-notify callback is a pointer to an array of void* pointers, 7880** and the second is the number of entries in the array. 7881** 7882** When a blocking connections transaction is concluded, there may be 7883** more than one blocked connection that has registered for an unlock-notify 7884** callback. ^If two or more such blocked connections have specified the 7885** same callback function, then instead of invoking the callback function 7886** multiple times, it is invoked once with the set of void* context pointers 7887** specified by the blocked connections bundled together into an array. 7888** This gives the application an opportunity to prioritize any actions 7889** related to the set of unblocked database connections. 7890** 7891** <b>Deadlock Detection</b> 7892** 7893** Assuming that after registering for an unlock-notify callback a 7894** database waits for the callback to be issued before taking any further 7895** action (a reasonable assumption), then using this API may cause the 7896** application to deadlock. For example, if connection X is waiting for 7897** connection Y's transaction to be concluded, and similarly connection 7898** Y is waiting on connection X's transaction, then neither connection 7899** will proceed and the system may remain deadlocked indefinitely. 7900** 7901** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7902** detection. ^If a given call to sqlite3_unlock_notify() would put the 7903** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7904** unlock-notify callback is registered. The system is said to be in 7905** a deadlocked state if connection A has registered for an unlock-notify 7906** callback on the conclusion of connection B's transaction, and connection 7907** B has itself registered for an unlock-notify callback when connection 7908** A's transaction is concluded. ^Indirect deadlock is also detected, so 7909** the system is also considered to be deadlocked if connection B has 7910** registered for an unlock-notify callback on the conclusion of connection 7911** C's transaction, where connection C is waiting on connection A. ^Any 7912** number of levels of indirection are allowed. 7913** 7914** <b>The "DROP TABLE" Exception</b> 7915** 7916** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7917** always appropriate to call sqlite3_unlock_notify(). There is however, 7918** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7919** SQLite checks if there are any currently executing SELECT statements 7920** that belong to the same connection. If there are, SQLITE_LOCKED is 7921** returned. In this case there is no "blocking connection", so invoking 7922** sqlite3_unlock_notify() results in the unlock-notify callback being 7923** invoked immediately. If the application then re-attempts the "DROP TABLE" 7924** or "DROP INDEX" query, an infinite loop might be the result. 7925** 7926** One way around this problem is to check the extended error code returned 7927** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7928** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7929** the special "DROP TABLE/INDEX" case, the extended error code is just 7930** SQLITE_LOCKED.)^ 7931*/ 7932int sqlite3_unlock_notify( 7933 sqlite3 *pBlocked, /* Waiting connection */ 7934 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7935 void *pNotifyArg /* Argument to pass to xNotify */ 7936); 7937 7938 7939/* 7940** CAPI3REF: String Comparison 7941** 7942** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7943** and extensions to compare the contents of two buffers containing UTF-8 7944** strings in a case-independent fashion, using the same definition of "case 7945** independence" that SQLite uses internally when comparing identifiers. 7946*/ 7947int sqlite3_stricmp(const char *, const char *); 7948int sqlite3_strnicmp(const char *, const char *, int); 7949 7950/* 7951** CAPI3REF: String Globbing 7952* 7953** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7954** string X matches the [GLOB] pattern P. 7955** ^The definition of [GLOB] pattern matching used in 7956** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7957** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7958** is case sensitive. 7959** 7960** Note that this routine returns zero on a match and non-zero if the strings 7961** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7962** 7963** See also: [sqlite3_strlike()]. 7964*/ 7965int sqlite3_strglob(const char *zGlob, const char *zStr); 7966 7967/* 7968** CAPI3REF: String LIKE Matching 7969* 7970** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7971** string X matches the [LIKE] pattern P with escape character E. 7972** ^The definition of [LIKE] pattern matching used in 7973** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7974** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7975** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7976** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7977** insensitive - equivalent upper and lower case ASCII characters match 7978** one another. 7979** 7980** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7981** only ASCII characters are case folded. 7982** 7983** Note that this routine returns zero on a match and non-zero if the strings 7984** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7985** 7986** See also: [sqlite3_strglob()]. 7987*/ 7988int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7989 7990/* 7991** CAPI3REF: Error Logging Interface 7992** 7993** ^The [sqlite3_log()] interface writes a message into the [error log] 7994** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7995** ^If logging is enabled, the zFormat string and subsequent arguments are 7996** used with [sqlite3_snprintf()] to generate the final output string. 7997** 7998** The sqlite3_log() interface is intended for use by extensions such as 7999** virtual tables, collating functions, and SQL functions. While there is 8000** nothing to prevent an application from calling sqlite3_log(), doing so 8001** is considered bad form. 8002** 8003** The zFormat string must not be NULL. 8004** 8005** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8006** will not use dynamically allocated memory. The log message is stored in 8007** a fixed-length buffer on the stack. If the log message is longer than 8008** a few hundred characters, it will be truncated to the length of the 8009** buffer. 8010*/ 8011void sqlite3_log(int iErrCode, const char *zFormat, ...); 8012 8013/* 8014** CAPI3REF: Write-Ahead Log Commit Hook 8015** METHOD: sqlite3 8016** 8017** ^The [sqlite3_wal_hook()] function is used to register a callback that 8018** is invoked each time data is committed to a database in wal mode. 8019** 8020** ^(The callback is invoked by SQLite after the commit has taken place and 8021** the associated write-lock on the database released)^, so the implementation 8022** may read, write or [checkpoint] the database as required. 8023** 8024** ^The first parameter passed to the callback function when it is invoked 8025** is a copy of the third parameter passed to sqlite3_wal_hook() when 8026** registering the callback. ^The second is a copy of the database handle. 8027** ^The third parameter is the name of the database that was written to - 8028** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8029** is the number of pages currently in the write-ahead log file, 8030** including those that were just committed. 8031** 8032** The callback function should normally return [SQLITE_OK]. ^If an error 8033** code is returned, that error will propagate back up through the 8034** SQLite code base to cause the statement that provoked the callback 8035** to report an error, though the commit will have still occurred. If the 8036** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8037** that does not correspond to any valid SQLite error code, the results 8038** are undefined. 8039** 8040** A single database handle may have at most a single write-ahead log callback 8041** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8042** previously registered write-ahead log callback. ^Note that the 8043** [sqlite3_wal_autocheckpoint()] interface and the 8044** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8045** overwrite any prior [sqlite3_wal_hook()] settings. 8046*/ 8047void *sqlite3_wal_hook( 8048 sqlite3*, 8049 int(*)(void *,sqlite3*,const char*,int), 8050 void* 8051); 8052 8053/* 8054** CAPI3REF: Configure an auto-checkpoint 8055** METHOD: sqlite3 8056** 8057** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8058** [sqlite3_wal_hook()] that causes any database on [database connection] D 8059** to automatically [checkpoint] 8060** after committing a transaction if there are N or 8061** more frames in the [write-ahead log] file. ^Passing zero or 8062** a negative value as the nFrame parameter disables automatic 8063** checkpoints entirely. 8064** 8065** ^The callback registered by this function replaces any existing callback 8066** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8067** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8068** configured by this function. 8069** 8070** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8071** from SQL. 8072** 8073** ^Checkpoints initiated by this mechanism are 8074** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8075** 8076** ^Every new [database connection] defaults to having the auto-checkpoint 8077** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8078** pages. The use of this interface 8079** is only necessary if the default setting is found to be suboptimal 8080** for a particular application. 8081*/ 8082int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8083 8084/* 8085** CAPI3REF: Checkpoint a database 8086** METHOD: sqlite3 8087** 8088** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8089** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8090** 8091** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8092** [write-ahead log] for database X on [database connection] D to be 8093** transferred into the database file and for the write-ahead log to 8094** be reset. See the [checkpointing] documentation for addition 8095** information. 8096** 8097** This interface used to be the only way to cause a checkpoint to 8098** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8099** interface was added. This interface is retained for backwards 8100** compatibility and as a convenience for applications that need to manually 8101** start a callback but which do not need the full power (and corresponding 8102** complication) of [sqlite3_wal_checkpoint_v2()]. 8103*/ 8104int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8105 8106/* 8107** CAPI3REF: Checkpoint a database 8108** METHOD: sqlite3 8109** 8110** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8111** operation on database X of [database connection] D in mode M. Status 8112** information is written back into integers pointed to by L and C.)^ 8113** ^(The M parameter must be a valid [checkpoint mode]:)^ 8114** 8115** <dl> 8116** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8117** ^Checkpoint as many frames as possible without waiting for any database 8118** readers or writers to finish, then sync the database file if all frames 8119** in the log were checkpointed. ^The [busy-handler callback] 8120** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8121** ^On the other hand, passive mode might leave the checkpoint unfinished 8122** if there are concurrent readers or writers. 8123** 8124** <dt>SQLITE_CHECKPOINT_FULL<dd> 8125** ^This mode blocks (it invokes the 8126** [sqlite3_busy_handler|busy-handler callback]) until there is no 8127** database writer and all readers are reading from the most recent database 8128** snapshot. ^It then checkpoints all frames in the log file and syncs the 8129** database file. ^This mode blocks new database writers while it is pending, 8130** but new database readers are allowed to continue unimpeded. 8131** 8132** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8133** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8134** that after checkpointing the log file it blocks (calls the 8135** [busy-handler callback]) 8136** until all readers are reading from the database file only. ^This ensures 8137** that the next writer will restart the log file from the beginning. 8138** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8139** database writer attempts while it is pending, but does not impede readers. 8140** 8141** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8142** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8143** addition that it also truncates the log file to zero bytes just prior 8144** to a successful return. 8145** </dl> 8146** 8147** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8148** the log file or to -1 if the checkpoint could not run because 8149** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8150** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8151** log file (including any that were already checkpointed before the function 8152** was called) or to -1 if the checkpoint could not run due to an error or 8153** because the database is not in WAL mode. ^Note that upon successful 8154** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8155** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8156** 8157** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8158** any other process is running a checkpoint operation at the same time, the 8159** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8160** busy-handler configured, it will not be invoked in this case. 8161** 8162** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8163** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8164** obtained immediately, and a busy-handler is configured, it is invoked and 8165** the writer lock retried until either the busy-handler returns 0 or the lock 8166** is successfully obtained. ^The busy-handler is also invoked while waiting for 8167** database readers as described above. ^If the busy-handler returns 0 before 8168** the writer lock is obtained or while waiting for database readers, the 8169** checkpoint operation proceeds from that point in the same way as 8170** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8171** without blocking any further. ^SQLITE_BUSY is returned in this case. 8172** 8173** ^If parameter zDb is NULL or points to a zero length string, then the 8174** specified operation is attempted on all WAL databases [attached] to 8175** [database connection] db. In this case the 8176** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8177** an SQLITE_BUSY error is encountered when processing one or more of the 8178** attached WAL databases, the operation is still attempted on any remaining 8179** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8180** error occurs while processing an attached database, processing is abandoned 8181** and the error code is returned to the caller immediately. ^If no error 8182** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8183** databases, SQLITE_OK is returned. 8184** 8185** ^If database zDb is the name of an attached database that is not in WAL 8186** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8187** zDb is not NULL (or a zero length string) and is not the name of any 8188** attached database, SQLITE_ERROR is returned to the caller. 8189** 8190** ^Unless it returns SQLITE_MISUSE, 8191** the sqlite3_wal_checkpoint_v2() interface 8192** sets the error information that is queried by 8193** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8194** 8195** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8196** from SQL. 8197*/ 8198int sqlite3_wal_checkpoint_v2( 8199 sqlite3 *db, /* Database handle */ 8200 const char *zDb, /* Name of attached database (or NULL) */ 8201 int eMode, /* SQLITE_CHECKPOINT_* value */ 8202 int *pnLog, /* OUT: Size of WAL log in frames */ 8203 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8204); 8205 8206/* 8207** CAPI3REF: Checkpoint Mode Values 8208** KEYWORDS: {checkpoint mode} 8209** 8210** These constants define all valid values for the "checkpoint mode" passed 8211** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8212** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8213** meaning of each of these checkpoint modes. 8214*/ 8215#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8216#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8217#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8218#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8219 8220/* 8221** CAPI3REF: Virtual Table Interface Configuration 8222** 8223** This function may be called by either the [xConnect] or [xCreate] method 8224** of a [virtual table] implementation to configure 8225** various facets of the virtual table interface. 8226** 8227** If this interface is invoked outside the context of an xConnect or 8228** xCreate virtual table method then the behavior is undefined. 8229** 8230** At present, there is only one option that may be configured using 8231** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8232** may be added in the future. 8233*/ 8234int sqlite3_vtab_config(sqlite3*, int op, ...); 8235 8236/* 8237** CAPI3REF: Virtual Table Configuration Options 8238** 8239** These macros define the various options to the 8240** [sqlite3_vtab_config()] interface that [virtual table] implementations 8241** can use to customize and optimize their behavior. 8242** 8243** <dl> 8244** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8245** <dd>Calls of the form 8246** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8247** where X is an integer. If X is zero, then the [virtual table] whose 8248** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8249** support constraints. In this configuration (which is the default) if 8250** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8251** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8252** specified as part of the users SQL statement, regardless of the actual 8253** ON CONFLICT mode specified. 8254** 8255** If X is non-zero, then the virtual table implementation guarantees 8256** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8257** any modifications to internal or persistent data structures have been made. 8258** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8259** is able to roll back a statement or database transaction, and abandon 8260** or continue processing the current SQL statement as appropriate. 8261** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8262** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8263** had been ABORT. 8264** 8265** Virtual table implementations that are required to handle OR REPLACE 8266** must do so within the [xUpdate] method. If a call to the 8267** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8268** CONFLICT policy is REPLACE, the virtual table implementation should 8269** silently replace the appropriate rows within the xUpdate callback and 8270** return SQLITE_OK. Or, if this is not possible, it may return 8271** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8272** constraint handling. 8273** </dl> 8274*/ 8275#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8276 8277/* 8278** CAPI3REF: Determine The Virtual Table Conflict Policy 8279** 8280** This function may only be called from within a call to the [xUpdate] method 8281** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8282** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8283** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8284** of the SQL statement that triggered the call to the [xUpdate] method of the 8285** [virtual table]. 8286*/ 8287int sqlite3_vtab_on_conflict(sqlite3 *); 8288 8289/* 8290** CAPI3REF: Conflict resolution modes 8291** KEYWORDS: {conflict resolution mode} 8292** 8293** These constants are returned by [sqlite3_vtab_on_conflict()] to 8294** inform a [virtual table] implementation what the [ON CONFLICT] mode 8295** is for the SQL statement being evaluated. 8296** 8297** Note that the [SQLITE_IGNORE] constant is also used as a potential 8298** return value from the [sqlite3_set_authorizer()] callback and that 8299** [SQLITE_ABORT] is also a [result code]. 8300*/ 8301#define SQLITE_ROLLBACK 1 8302/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8303#define SQLITE_FAIL 3 8304/* #define SQLITE_ABORT 4 // Also an error code */ 8305#define SQLITE_REPLACE 5 8306 8307/* 8308** CAPI3REF: Prepared Statement Scan Status Opcodes 8309** KEYWORDS: {scanstatus options} 8310** 8311** The following constants can be used for the T parameter to the 8312** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8313** different metric for sqlite3_stmt_scanstatus() to return. 8314** 8315** When the value returned to V is a string, space to hold that string is 8316** managed by the prepared statement S and will be automatically freed when 8317** S is finalized. 8318** 8319** <dl> 8320** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8321** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8322** set to the total number of times that the X-th loop has run.</dd> 8323** 8324** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8325** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8326** to the total number of rows examined by all iterations of the X-th loop.</dd> 8327** 8328** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8329** <dd>^The "double" variable pointed to by the T parameter will be set to the 8330** query planner's estimate for the average number of rows output from each 8331** iteration of the X-th loop. If the query planner's estimates was accurate, 8332** then this value will approximate the quotient NVISIT/NLOOP and the 8333** product of this value for all prior loops with the same SELECTID will 8334** be the NLOOP value for the current loop. 8335** 8336** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8337** <dd>^The "const char *" variable pointed to by the T parameter will be set 8338** to a zero-terminated UTF-8 string containing the name of the index or table 8339** used for the X-th loop. 8340** 8341** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8342** <dd>^The "const char *" variable pointed to by the T parameter will be set 8343** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8344** description for the X-th loop. 8345** 8346** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8347** <dd>^The "int" variable pointed to by the T parameter will be set to the 8348** "select-id" for the X-th loop. The select-id identifies which query or 8349** subquery the loop is part of. The main query has a select-id of zero. 8350** The select-id is the same value as is output in the first column 8351** of an [EXPLAIN QUERY PLAN] query. 8352** </dl> 8353*/ 8354#define SQLITE_SCANSTAT_NLOOP 0 8355#define SQLITE_SCANSTAT_NVISIT 1 8356#define SQLITE_SCANSTAT_EST 2 8357#define SQLITE_SCANSTAT_NAME 3 8358#define SQLITE_SCANSTAT_EXPLAIN 4 8359#define SQLITE_SCANSTAT_SELECTID 5 8360 8361/* 8362** CAPI3REF: Prepared Statement Scan Status 8363** METHOD: sqlite3_stmt 8364** 8365** This interface returns information about the predicted and measured 8366** performance for pStmt. Advanced applications can use this 8367** interface to compare the predicted and the measured performance and 8368** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8369** 8370** Since this interface is expected to be rarely used, it is only 8371** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8372** compile-time option. 8373** 8374** The "iScanStatusOp" parameter determines which status information to return. 8375** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8376** of this interface is undefined. 8377** ^The requested measurement is written into a variable pointed to by 8378** the "pOut" parameter. 8379** Parameter "idx" identifies the specific loop to retrieve statistics for. 8380** Loops are numbered starting from zero. ^If idx is out of range - less than 8381** zero or greater than or equal to the total number of loops used to implement 8382** the statement - a non-zero value is returned and the variable that pOut 8383** points to is unchanged. 8384** 8385** ^Statistics might not be available for all loops in all statements. ^In cases 8386** where there exist loops with no available statistics, this function behaves 8387** as if the loop did not exist - it returns non-zero and leave the variable 8388** that pOut points to unchanged. 8389** 8390** See also: [sqlite3_stmt_scanstatus_reset()] 8391*/ 8392int sqlite3_stmt_scanstatus( 8393 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8394 int idx, /* Index of loop to report on */ 8395 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8396 void *pOut /* Result written here */ 8397); 8398 8399/* 8400** CAPI3REF: Zero Scan-Status Counters 8401** METHOD: sqlite3_stmt 8402** 8403** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8404** 8405** This API is only available if the library is built with pre-processor 8406** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8407*/ 8408void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8409 8410/* 8411** CAPI3REF: Flush caches to disk mid-transaction 8412** 8413** ^If a write-transaction is open on [database connection] D when the 8414** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8415** pages in the pager-cache that are not currently in use are written out 8416** to disk. A dirty page may be in use if a database cursor created by an 8417** active SQL statement is reading from it, or if it is page 1 of a database 8418** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8419** interface flushes caches for all schemas - "main", "temp", and 8420** any [attached] databases. 8421** 8422** ^If this function needs to obtain extra database locks before dirty pages 8423** can be flushed to disk, it does so. ^If those locks cannot be obtained 8424** immediately and there is a busy-handler callback configured, it is invoked 8425** in the usual manner. ^If the required lock still cannot be obtained, then 8426** the database is skipped and an attempt made to flush any dirty pages 8427** belonging to the next (if any) database. ^If any databases are skipped 8428** because locks cannot be obtained, but no other error occurs, this 8429** function returns SQLITE_BUSY. 8430** 8431** ^If any other error occurs while flushing dirty pages to disk (for 8432** example an IO error or out-of-memory condition), then processing is 8433** abandoned and an SQLite [error code] is returned to the caller immediately. 8434** 8435** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8436** 8437** ^This function does not set the database handle error code or message 8438** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8439*/ 8440int sqlite3_db_cacheflush(sqlite3*); 8441 8442/* 8443** CAPI3REF: The pre-update hook. 8444** 8445** ^These interfaces are only available if SQLite is compiled using the 8446** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8447** 8448** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8449** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8450** on a database table. 8451** ^At most one preupdate hook may be registered at a time on a single 8452** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8453** the previous setting. 8454** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8455** with a NULL pointer as the second parameter. 8456** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8457** the first parameter to callbacks. 8458** 8459** ^The preupdate hook only fires for changes to real database tables; the 8460** preupdate hook is not invoked for changes to [virtual tables] or to 8461** system tables like sqlite_master or sqlite_stat1. 8462** 8463** ^The second parameter to the preupdate callback is a pointer to 8464** the [database connection] that registered the preupdate hook. 8465** ^The third parameter to the preupdate callback is one of the constants 8466** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8467** kind of update operation that is about to occur. 8468** ^(The fourth parameter to the preupdate callback is the name of the 8469** database within the database connection that is being modified. This 8470** will be "main" for the main database or "temp" for TEMP tables or 8471** the name given after the AS keyword in the [ATTACH] statement for attached 8472** databases.)^ 8473** ^The fifth parameter to the preupdate callback is the name of the 8474** table that is being modified. 8475** 8476** For an UPDATE or DELETE operation on a [rowid table], the sixth 8477** parameter passed to the preupdate callback is the initial [rowid] of the 8478** row being modified or deleted. For an INSERT operation on a rowid table, 8479** or any operation on a WITHOUT ROWID table, the value of the sixth 8480** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8481** seventh parameter is the final rowid value of the row being inserted 8482** or updated. The value of the seventh parameter passed to the callback 8483** function is not defined for operations on WITHOUT ROWID tables, or for 8484** INSERT operations on rowid tables. 8485** 8486** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8487** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8488** provide additional information about a preupdate event. These routines 8489** may only be called from within a preupdate callback. Invoking any of 8490** these routines from outside of a preupdate callback or with a 8491** [database connection] pointer that is different from the one supplied 8492** to the preupdate callback results in undefined and probably undesirable 8493** behavior. 8494** 8495** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8496** in the row that is being inserted, updated, or deleted. 8497** 8498** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8499** a [protected sqlite3_value] that contains the value of the Nth column of 8500** the table row before it is updated. The N parameter must be between 0 8501** and one less than the number of columns or the behavior will be 8502** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8503** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8504** behavior is undefined. The [sqlite3_value] that P points to 8505** will be destroyed when the preupdate callback returns. 8506** 8507** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8508** a [protected sqlite3_value] that contains the value of the Nth column of 8509** the table row after it is updated. The N parameter must be between 0 8510** and one less than the number of columns or the behavior will be 8511** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8512** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8513** behavior is undefined. The [sqlite3_value] that P points to 8514** will be destroyed when the preupdate callback returns. 8515** 8516** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8517** callback was invoked as a result of a direct insert, update, or delete 8518** operation; or 1 for inserts, updates, or deletes invoked by top-level 8519** triggers; or 2 for changes resulting from triggers called by top-level 8520** triggers; and so forth. 8521** 8522** See also: [sqlite3_update_hook()] 8523*/ 8524#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8525void *sqlite3_preupdate_hook( 8526 sqlite3 *db, 8527 void(*xPreUpdate)( 8528 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8529 sqlite3 *db, /* Database handle */ 8530 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8531 char const *zDb, /* Database name */ 8532 char const *zName, /* Table name */ 8533 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8534 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8535 ), 8536 void* 8537); 8538int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8539int sqlite3_preupdate_count(sqlite3 *); 8540int sqlite3_preupdate_depth(sqlite3 *); 8541int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8542#endif 8543 8544/* 8545** CAPI3REF: Low-level system error code 8546** 8547** ^Attempt to return the underlying operating system error code or error 8548** number that caused the most recent I/O error or failure to open a file. 8549** The return value is OS-dependent. For example, on unix systems, after 8550** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8551** called to get back the underlying "errno" that caused the problem, such 8552** as ENOSPC, EAUTH, EISDIR, and so forth. 8553*/ 8554int sqlite3_system_errno(sqlite3*); 8555 8556/* 8557** CAPI3REF: Database Snapshot 8558** KEYWORDS: {snapshot} {sqlite3_snapshot} 8559** EXPERIMENTAL 8560** 8561** An instance of the snapshot object records the state of a [WAL mode] 8562** database for some specific point in history. 8563** 8564** In [WAL mode], multiple [database connections] that are open on the 8565** same database file can each be reading a different historical version 8566** of the database file. When a [database connection] begins a read 8567** transaction, that connection sees an unchanging copy of the database 8568** as it existed for the point in time when the transaction first started. 8569** Subsequent changes to the database from other connections are not seen 8570** by the reader until a new read transaction is started. 8571** 8572** The sqlite3_snapshot object records state information about an historical 8573** version of the database file so that it is possible to later open a new read 8574** transaction that sees that historical version of the database rather than 8575** the most recent version. 8576** 8577** The constructor for this object is [sqlite3_snapshot_get()]. The 8578** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8579** to an historical snapshot (if possible). The destructor for 8580** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8581*/ 8582typedef struct sqlite3_snapshot { 8583 unsigned char hidden[48]; 8584} sqlite3_snapshot; 8585 8586/* 8587** CAPI3REF: Record A Database Snapshot 8588** EXPERIMENTAL 8589** 8590** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8591** new [sqlite3_snapshot] object that records the current state of 8592** schema S in database connection D. ^On success, the 8593** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8594** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8595** If there is not already a read-transaction open on schema S when 8596** this function is called, one is opened automatically. 8597** 8598** The following must be true for this function to succeed. If any of 8599** the following statements are false when sqlite3_snapshot_get() is 8600** called, SQLITE_ERROR is returned. The final value of *P is undefined 8601** in this case. 8602** 8603** <ul> 8604** <li> The database handle must be in [autocommit mode]. 8605** 8606** <li> Schema S of [database connection] D must be a [WAL mode] database. 8607** 8608** <li> There must not be a write transaction open on schema S of database 8609** connection D. 8610** 8611** <li> One or more transactions must have been written to the current wal 8612** file since it was created on disk (by any connection). This means 8613** that a snapshot cannot be taken on a wal mode database with no wal 8614** file immediately after it is first opened. At least one transaction 8615** must be written to it first. 8616** </ul> 8617** 8618** This function may also return SQLITE_NOMEM. If it is called with the 8619** database handle in autocommit mode but fails for some other reason, 8620** whether or not a read transaction is opened on schema S is undefined. 8621** 8622** The [sqlite3_snapshot] object returned from a successful call to 8623** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8624** to avoid a memory leak. 8625** 8626** The [sqlite3_snapshot_get()] interface is only available when the 8627** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8628*/ 8629SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8630 sqlite3 *db, 8631 const char *zSchema, 8632 sqlite3_snapshot **ppSnapshot 8633); 8634 8635/* 8636** CAPI3REF: Start a read transaction on an historical snapshot 8637** EXPERIMENTAL 8638** 8639** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8640** read transaction for schema S of 8641** [database connection] D such that the read transaction 8642** refers to historical [snapshot] P, rather than the most 8643** recent change to the database. 8644** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8645** or an appropriate [error code] if it fails. 8646** 8647** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8648** the first operation following the [BEGIN] that takes the schema S 8649** out of [autocommit mode]. 8650** ^In other words, schema S must not currently be in 8651** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8652** database connection D must be out of [autocommit mode]. 8653** ^A [snapshot] will fail to open if it has been overwritten by a 8654** [checkpoint]. 8655** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8656** database connection D does not know that the database file for 8657** schema S is in [WAL mode]. A database connection might not know 8658** that the database file is in [WAL mode] if there has been no prior 8659** I/O on that database connection, or if the database entered [WAL mode] 8660** after the most recent I/O on the database connection.)^ 8661** (Hint: Run "[PRAGMA application_id]" against a newly opened 8662** database connection in order to make it ready to use snapshots.) 8663** 8664** The [sqlite3_snapshot_open()] interface is only available when the 8665** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8666*/ 8667SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8668 sqlite3 *db, 8669 const char *zSchema, 8670 sqlite3_snapshot *pSnapshot 8671); 8672 8673/* 8674** CAPI3REF: Destroy a snapshot 8675** EXPERIMENTAL 8676** 8677** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8678** The application must eventually free every [sqlite3_snapshot] object 8679** using this routine to avoid a memory leak. 8680** 8681** The [sqlite3_snapshot_free()] interface is only available when the 8682** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8683*/ 8684SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8685 8686/* 8687** CAPI3REF: Compare the ages of two snapshot handles. 8688** EXPERIMENTAL 8689** 8690** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8691** of two valid snapshot handles. 8692** 8693** If the two snapshot handles are not associated with the same database 8694** file, the result of the comparison is undefined. 8695** 8696** Additionally, the result of the comparison is only valid if both of the 8697** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8698** last time the wal file was deleted. The wal file is deleted when the 8699** database is changed back to rollback mode or when the number of database 8700** clients drops to zero. If either snapshot handle was obtained before the 8701** wal file was last deleted, the value returned by this function 8702** is undefined. 8703** 8704** Otherwise, this API returns a negative value if P1 refers to an older 8705** snapshot than P2, zero if the two handles refer to the same database 8706** snapshot, and a positive value if P1 is a newer snapshot than P2. 8707*/ 8708SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8709 sqlite3_snapshot *p1, 8710 sqlite3_snapshot *p2 8711); 8712 8713/* 8714** CAPI3REF: Recover snapshots from a wal file 8715** EXPERIMENTAL 8716** 8717** If all connections disconnect from a database file but do not perform 8718** a checkpoint, the existing wal file is opened along with the database 8719** file the next time the database is opened. At this point it is only 8720** possible to successfully call sqlite3_snapshot_open() to open the most 8721** recent snapshot of the database (the one at the head of the wal file), 8722** even though the wal file may contain other valid snapshots for which 8723** clients have sqlite3_snapshot handles. 8724** 8725** This function attempts to scan the wal file associated with database zDb 8726** of database handle db and make all valid snapshots available to 8727** sqlite3_snapshot_open(). It is an error if there is already a read 8728** transaction open on the database, or if the database is not a wal mode 8729** database. 8730** 8731** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8732*/ 8733SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8734 8735/* 8736** Undo the hack that converts floating point types to integer for 8737** builds on processors without floating point support. 8738*/ 8739#ifdef SQLITE_OMIT_FLOATING_POINT 8740# undef double 8741#endif 8742 8743#ifdef __cplusplus 8744} /* End of the 'extern "C"' block */ 8745#endif 8746#endif /* SQLITE3_H */ 8747