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_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 514#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 515#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 516#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 517#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 518#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 519#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<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** 1068** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1069** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain 1070** a file lock using the xLock or xShmLock methods of the VFS to wait 1071** for up to M milliseconds before failing, where M is the single 1072** unsigned integer parameter. 1073** </ul> 1074*/ 1075#define SQLITE_FCNTL_LOCKSTATE 1 1076#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1077#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1078#define SQLITE_FCNTL_LAST_ERRNO 4 1079#define SQLITE_FCNTL_SIZE_HINT 5 1080#define SQLITE_FCNTL_CHUNK_SIZE 6 1081#define SQLITE_FCNTL_FILE_POINTER 7 1082#define SQLITE_FCNTL_SYNC_OMITTED 8 1083#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1084#define SQLITE_FCNTL_PERSIST_WAL 10 1085#define SQLITE_FCNTL_OVERWRITE 11 1086#define SQLITE_FCNTL_VFSNAME 12 1087#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1088#define SQLITE_FCNTL_PRAGMA 14 1089#define SQLITE_FCNTL_BUSYHANDLER 15 1090#define SQLITE_FCNTL_TEMPFILENAME 16 1091#define SQLITE_FCNTL_MMAP_SIZE 18 1092#define SQLITE_FCNTL_TRACE 19 1093#define SQLITE_FCNTL_HAS_MOVED 20 1094#define SQLITE_FCNTL_SYNC 21 1095#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1096#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1097#define SQLITE_FCNTL_WAL_BLOCK 24 1098#define SQLITE_FCNTL_ZIPVFS 25 1099#define SQLITE_FCNTL_RBU 26 1100#define SQLITE_FCNTL_VFS_POINTER 27 1101#define SQLITE_FCNTL_JOURNAL_POINTER 28 1102#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1103#define SQLITE_FCNTL_PDB 30 1104#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1105#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1106#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1107#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1108 1109/* deprecated names */ 1110#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1111#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1112#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1113 1114 1115/* 1116** CAPI3REF: Mutex Handle 1117** 1118** The mutex module within SQLite defines [sqlite3_mutex] to be an 1119** abstract type for a mutex object. The SQLite core never looks 1120** at the internal representation of an [sqlite3_mutex]. It only 1121** deals with pointers to the [sqlite3_mutex] object. 1122** 1123** Mutexes are created using [sqlite3_mutex_alloc()]. 1124*/ 1125typedef struct sqlite3_mutex sqlite3_mutex; 1126 1127/* 1128** CAPI3REF: Loadable Extension Thunk 1129** 1130** A pointer to the opaque sqlite3_api_routines structure is passed as 1131** the third parameter to entry points of [loadable extensions]. This 1132** structure must be typedefed in order to work around compiler warnings 1133** on some platforms. 1134*/ 1135typedef struct sqlite3_api_routines sqlite3_api_routines; 1136 1137/* 1138** CAPI3REF: OS Interface Object 1139** 1140** An instance of the sqlite3_vfs object defines the interface between 1141** the SQLite core and the underlying operating system. The "vfs" 1142** in the name of the object stands for "virtual file system". See 1143** the [VFS | VFS documentation] for further information. 1144** 1145** The VFS interface is sometimes extended by adding new methods onto 1146** the end. Each time such an extension occurs, the iVersion field 1147** is incremented. The iVersion value started out as 1 in 1148** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1149** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1150** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1151** may be appended to the sqlite3_vfs object and the iVersion value 1152** may increase again in future versions of SQLite. 1153** Note that the structure 1154** of the sqlite3_vfs object changes in the transition from 1155** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1156** and yet the iVersion field was not modified. 1157** 1158** The szOsFile field is the size of the subclassed [sqlite3_file] 1159** structure used by this VFS. mxPathname is the maximum length of 1160** a pathname in this VFS. 1161** 1162** Registered sqlite3_vfs objects are kept on a linked list formed by 1163** the pNext pointer. The [sqlite3_vfs_register()] 1164** and [sqlite3_vfs_unregister()] interfaces manage this list 1165** in a thread-safe way. The [sqlite3_vfs_find()] interface 1166** searches the list. Neither the application code nor the VFS 1167** implementation should use the pNext pointer. 1168** 1169** The pNext field is the only field in the sqlite3_vfs 1170** structure that SQLite will ever modify. SQLite will only access 1171** or modify this field while holding a particular static mutex. 1172** The application should never modify anything within the sqlite3_vfs 1173** object once the object has been registered. 1174** 1175** The zName field holds the name of the VFS module. The name must 1176** be unique across all VFS modules. 1177** 1178** [[sqlite3_vfs.xOpen]] 1179** ^SQLite guarantees that the zFilename parameter to xOpen 1180** is either a NULL pointer or string obtained 1181** from xFullPathname() with an optional suffix added. 1182** ^If a suffix is added to the zFilename parameter, it will 1183** consist of a single "-" character followed by no more than 1184** 11 alphanumeric and/or "-" characters. 1185** ^SQLite further guarantees that 1186** the string will be valid and unchanged until xClose() is 1187** called. Because of the previous sentence, 1188** the [sqlite3_file] can safely store a pointer to the 1189** filename if it needs to remember the filename for some reason. 1190** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1191** must invent its own temporary name for the file. ^Whenever the 1192** xFilename parameter is NULL it will also be the case that the 1193** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1194** 1195** The flags argument to xOpen() includes all bits set in 1196** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1197** or [sqlite3_open16()] is used, then flags includes at least 1198** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1199** If xOpen() opens a file read-only then it sets *pOutFlags to 1200** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1201** 1202** ^(SQLite will also add one of the following flags to the xOpen() 1203** call, depending on the object being opened: 1204** 1205** <ul> 1206** <li> [SQLITE_OPEN_MAIN_DB] 1207** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1208** <li> [SQLITE_OPEN_TEMP_DB] 1209** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1210** <li> [SQLITE_OPEN_TRANSIENT_DB] 1211** <li> [SQLITE_OPEN_SUBJOURNAL] 1212** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1213** <li> [SQLITE_OPEN_WAL] 1214** </ul>)^ 1215** 1216** The file I/O implementation can use the object type flags to 1217** change the way it deals with files. For example, an application 1218** that does not care about crash recovery or rollback might make 1219** the open of a journal file a no-op. Writes to this journal would 1220** also be no-ops, and any attempt to read the journal would return 1221** SQLITE_IOERR. Or the implementation might recognize that a database 1222** file will be doing page-aligned sector reads and writes in a random 1223** order and set up its I/O subsystem accordingly. 1224** 1225** SQLite might also add one of the following flags to the xOpen method: 1226** 1227** <ul> 1228** <li> [SQLITE_OPEN_DELETEONCLOSE] 1229** <li> [SQLITE_OPEN_EXCLUSIVE] 1230** </ul> 1231** 1232** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1233** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1234** will be set for TEMP databases and their journals, transient 1235** databases, and subjournals. 1236** 1237** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1238** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1239** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1240** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1241** SQLITE_OPEN_CREATE, is used to indicate that file should always 1242** be created, and that it is an error if it already exists. 1243** It is <i>not</i> used to indicate the file should be opened 1244** for exclusive access. 1245** 1246** ^At least szOsFile bytes of memory are allocated by SQLite 1247** to hold the [sqlite3_file] structure passed as the third 1248** argument to xOpen. The xOpen method does not have to 1249** allocate the structure; it should just fill it in. Note that 1250** the xOpen method must set the sqlite3_file.pMethods to either 1251** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1252** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1253** element will be valid after xOpen returns regardless of the success 1254** or failure of the xOpen call. 1255** 1256** [[sqlite3_vfs.xAccess]] 1257** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1258** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1259** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1260** to test whether a file is at least readable. The file can be a 1261** directory. 1262** 1263** ^SQLite will always allocate at least mxPathname+1 bytes for the 1264** output buffer xFullPathname. The exact size of the output buffer 1265** is also passed as a parameter to both methods. If the output buffer 1266** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1267** handled as a fatal error by SQLite, vfs implementations should endeavor 1268** to prevent this by setting mxPathname to a sufficiently large value. 1269** 1270** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1271** interfaces are not strictly a part of the filesystem, but they are 1272** included in the VFS structure for completeness. 1273** The xRandomness() function attempts to return nBytes bytes 1274** of good-quality randomness into zOut. The return value is 1275** the actual number of bytes of randomness obtained. 1276** The xSleep() method causes the calling thread to sleep for at 1277** least the number of microseconds given. ^The xCurrentTime() 1278** method returns a Julian Day Number for the current date and time as 1279** a floating point value. 1280** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1281** Day Number multiplied by 86400000 (the number of milliseconds in 1282** a 24-hour day). 1283** ^SQLite will use the xCurrentTimeInt64() method to get the current 1284** date and time if that method is available (if iVersion is 2 or 1285** greater and the function pointer is not NULL) and will fall back 1286** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1287** 1288** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1289** are not used by the SQLite core. These optional interfaces are provided 1290** by some VFSes to facilitate testing of the VFS code. By overriding 1291** system calls with functions under its control, a test program can 1292** simulate faults and error conditions that would otherwise be difficult 1293** or impossible to induce. The set of system calls that can be overridden 1294** varies from one VFS to another, and from one version of the same VFS to the 1295** next. Applications that use these interfaces must be prepared for any 1296** or all of these interfaces to be NULL or for their behavior to change 1297** from one release to the next. Applications must not attempt to access 1298** any of these methods if the iVersion of the VFS is less than 3. 1299*/ 1300typedef struct sqlite3_vfs sqlite3_vfs; 1301typedef void (*sqlite3_syscall_ptr)(void); 1302struct sqlite3_vfs { 1303 int iVersion; /* Structure version number (currently 3) */ 1304 int szOsFile; /* Size of subclassed sqlite3_file */ 1305 int mxPathname; /* Maximum file pathname length */ 1306 sqlite3_vfs *pNext; /* Next registered VFS */ 1307 const char *zName; /* Name of this virtual file system */ 1308 void *pAppData; /* Pointer to application-specific data */ 1309 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1310 int flags, int *pOutFlags); 1311 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1312 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1313 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1314 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1315 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1316 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1317 void (*xDlClose)(sqlite3_vfs*, void*); 1318 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1319 int (*xSleep)(sqlite3_vfs*, int microseconds); 1320 int (*xCurrentTime)(sqlite3_vfs*, double*); 1321 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1322 /* 1323 ** The methods above are in version 1 of the sqlite_vfs object 1324 ** definition. Those that follow are added in version 2 or later 1325 */ 1326 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1327 /* 1328 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1329 ** Those below are for version 3 and greater. 1330 */ 1331 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1332 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1333 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1334 /* 1335 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1336 ** New fields may be appended in future versions. The iVersion 1337 ** value will increment whenever this happens. 1338 */ 1339}; 1340 1341/* 1342** CAPI3REF: Flags for the xAccess VFS method 1343** 1344** These integer constants can be used as the third parameter to 1345** the xAccess method of an [sqlite3_vfs] object. They determine 1346** what kind of permissions the xAccess method is looking for. 1347** With SQLITE_ACCESS_EXISTS, the xAccess method 1348** simply checks whether the file exists. 1349** With SQLITE_ACCESS_READWRITE, the xAccess method 1350** checks whether the named directory is both readable and writable 1351** (in other words, if files can be added, removed, and renamed within 1352** the directory). 1353** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1354** [temp_store_directory pragma], though this could change in a future 1355** release of SQLite. 1356** With SQLITE_ACCESS_READ, the xAccess method 1357** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1358** currently unused, though it might be used in a future release of 1359** SQLite. 1360*/ 1361#define SQLITE_ACCESS_EXISTS 0 1362#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1363#define SQLITE_ACCESS_READ 2 /* Unused */ 1364 1365/* 1366** CAPI3REF: Flags for the xShmLock VFS method 1367** 1368** These integer constants define the various locking operations 1369** allowed by the xShmLock method of [sqlite3_io_methods]. The 1370** following are the only legal combinations of flags to the 1371** xShmLock method: 1372** 1373** <ul> 1374** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1375** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1376** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1377** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1378** </ul> 1379** 1380** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1381** was given on the corresponding lock. 1382** 1383** The xShmLock method can transition between unlocked and SHARED or 1384** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1385** and EXCLUSIVE. 1386*/ 1387#define SQLITE_SHM_UNLOCK 1 1388#define SQLITE_SHM_LOCK 2 1389#define SQLITE_SHM_SHARED 4 1390#define SQLITE_SHM_EXCLUSIVE 8 1391 1392/* 1393** CAPI3REF: Maximum xShmLock index 1394** 1395** The xShmLock method on [sqlite3_io_methods] may use values 1396** between 0 and this upper bound as its "offset" argument. 1397** The SQLite core will never attempt to acquire or release a 1398** lock outside of this range 1399*/ 1400#define SQLITE_SHM_NLOCK 8 1401 1402 1403/* 1404** CAPI3REF: Initialize The SQLite Library 1405** 1406** ^The sqlite3_initialize() routine initializes the 1407** SQLite library. ^The sqlite3_shutdown() routine 1408** deallocates any resources that were allocated by sqlite3_initialize(). 1409** These routines are designed to aid in process initialization and 1410** shutdown on embedded systems. Workstation applications using 1411** SQLite normally do not need to invoke either of these routines. 1412** 1413** A call to sqlite3_initialize() is an "effective" call if it is 1414** the first time sqlite3_initialize() is invoked during the lifetime of 1415** the process, or if it is the first time sqlite3_initialize() is invoked 1416** following a call to sqlite3_shutdown(). ^(Only an effective call 1417** of sqlite3_initialize() does any initialization. All other calls 1418** are harmless no-ops.)^ 1419** 1420** A call to sqlite3_shutdown() is an "effective" call if it is the first 1421** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1422** an effective call to sqlite3_shutdown() does any deinitialization. 1423** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1424** 1425** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1426** is not. The sqlite3_shutdown() interface must only be called from a 1427** single thread. All open [database connections] must be closed and all 1428** other SQLite resources must be deallocated prior to invoking 1429** sqlite3_shutdown(). 1430** 1431** Among other things, ^sqlite3_initialize() will invoke 1432** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1433** will invoke sqlite3_os_end(). 1434** 1435** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1436** ^If for some reason, sqlite3_initialize() is unable to initialize 1437** the library (perhaps it is unable to allocate a needed resource such 1438** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1439** 1440** ^The sqlite3_initialize() routine is called internally by many other 1441** SQLite interfaces so that an application usually does not need to 1442** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1443** calls sqlite3_initialize() so the SQLite library will be automatically 1444** initialized when [sqlite3_open()] is called if it has not be initialized 1445** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1446** compile-time option, then the automatic calls to sqlite3_initialize() 1447** are omitted and the application must call sqlite3_initialize() directly 1448** prior to using any other SQLite interface. For maximum portability, 1449** it is recommended that applications always invoke sqlite3_initialize() 1450** directly prior to using any other SQLite interface. Future releases 1451** of SQLite may require this. In other words, the behavior exhibited 1452** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1453** default behavior in some future release of SQLite. 1454** 1455** The sqlite3_os_init() routine does operating-system specific 1456** initialization of the SQLite library. The sqlite3_os_end() 1457** routine undoes the effect of sqlite3_os_init(). Typical tasks 1458** performed by these routines include allocation or deallocation 1459** of static resources, initialization of global variables, 1460** setting up a default [sqlite3_vfs] module, or setting up 1461** a default configuration using [sqlite3_config()]. 1462** 1463** The application should never invoke either sqlite3_os_init() 1464** or sqlite3_os_end() directly. The application should only invoke 1465** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1466** interface is called automatically by sqlite3_initialize() and 1467** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1468** implementations for sqlite3_os_init() and sqlite3_os_end() 1469** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1470** When [custom builds | built for other platforms] 1471** (using the [SQLITE_OS_OTHER=1] compile-time 1472** option) the application must supply a suitable implementation for 1473** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1474** implementation of sqlite3_os_init() or sqlite3_os_end() 1475** must return [SQLITE_OK] on success and some other [error code] upon 1476** failure. 1477*/ 1478int sqlite3_initialize(void); 1479int sqlite3_shutdown(void); 1480int sqlite3_os_init(void); 1481int sqlite3_os_end(void); 1482 1483/* 1484** CAPI3REF: Configuring The SQLite Library 1485** 1486** The sqlite3_config() interface is used to make global configuration 1487** changes to SQLite in order to tune SQLite to the specific needs of 1488** the application. The default configuration is recommended for most 1489** applications and so this routine is usually not necessary. It is 1490** provided to support rare applications with unusual needs. 1491** 1492** <b>The sqlite3_config() interface is not threadsafe. The application 1493** must ensure that no other SQLite interfaces are invoked by other 1494** threads while sqlite3_config() is running.</b> 1495** 1496** The sqlite3_config() interface 1497** may only be invoked prior to library initialization using 1498** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1499** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1500** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1501** Note, however, that ^sqlite3_config() can be called as part of the 1502** implementation of an application-defined [sqlite3_os_init()]. 1503** 1504** The first argument to sqlite3_config() is an integer 1505** [configuration option] that determines 1506** what property of SQLite is to be configured. Subsequent arguments 1507** vary depending on the [configuration option] 1508** in the first argument. 1509** 1510** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1511** ^If the option is unknown or SQLite is unable to set the option 1512** then this routine returns a non-zero [error code]. 1513*/ 1514int sqlite3_config(int, ...); 1515 1516/* 1517** CAPI3REF: Configure database connections 1518** METHOD: sqlite3 1519** 1520** The sqlite3_db_config() interface is used to make configuration 1521** changes to a [database connection]. The interface is similar to 1522** [sqlite3_config()] except that the changes apply to a single 1523** [database connection] (specified in the first argument). 1524** 1525** The second argument to sqlite3_db_config(D,V,...) is the 1526** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1527** that indicates what aspect of the [database connection] is being configured. 1528** Subsequent arguments vary depending on the configuration verb. 1529** 1530** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1531** the call is considered successful. 1532*/ 1533int sqlite3_db_config(sqlite3*, int op, ...); 1534 1535/* 1536** CAPI3REF: Memory Allocation Routines 1537** 1538** An instance of this object defines the interface between SQLite 1539** and low-level memory allocation routines. 1540** 1541** This object is used in only one place in the SQLite interface. 1542** A pointer to an instance of this object is the argument to 1543** [sqlite3_config()] when the configuration option is 1544** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1545** By creating an instance of this object 1546** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1547** during configuration, an application can specify an alternative 1548** memory allocation subsystem for SQLite to use for all of its 1549** dynamic memory needs. 1550** 1551** Note that SQLite comes with several [built-in memory allocators] 1552** that are perfectly adequate for the overwhelming majority of applications 1553** and that this object is only useful to a tiny minority of applications 1554** with specialized memory allocation requirements. This object is 1555** also used during testing of SQLite in order to specify an alternative 1556** memory allocator that simulates memory out-of-memory conditions in 1557** order to verify that SQLite recovers gracefully from such 1558** conditions. 1559** 1560** The xMalloc, xRealloc, and xFree methods must work like the 1561** malloc(), realloc() and free() functions from the standard C library. 1562** ^SQLite guarantees that the second argument to 1563** xRealloc is always a value returned by a prior call to xRoundup. 1564** 1565** xSize should return the allocated size of a memory allocation 1566** previously obtained from xMalloc or xRealloc. The allocated size 1567** is always at least as big as the requested size but may be larger. 1568** 1569** The xRoundup method returns what would be the allocated size of 1570** a memory allocation given a particular requested size. Most memory 1571** allocators round up memory allocations at least to the next multiple 1572** of 8. Some allocators round up to a larger multiple or to a power of 2. 1573** Every memory allocation request coming in through [sqlite3_malloc()] 1574** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1575** that causes the corresponding memory allocation to fail. 1576** 1577** The xInit method initializes the memory allocator. For example, 1578** it might allocate any require mutexes or initialize internal data 1579** structures. The xShutdown method is invoked (indirectly) by 1580** [sqlite3_shutdown()] and should deallocate any resources acquired 1581** by xInit. The pAppData pointer is used as the only parameter to 1582** xInit and xShutdown. 1583** 1584** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1585** the xInit method, so the xInit method need not be threadsafe. The 1586** xShutdown method is only called from [sqlite3_shutdown()] so it does 1587** not need to be threadsafe either. For all other methods, SQLite 1588** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1589** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1590** it is by default) and so the methods are automatically serialized. 1591** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1592** methods must be threadsafe or else make their own arrangements for 1593** serialization. 1594** 1595** SQLite will never invoke xInit() more than once without an intervening 1596** call to xShutdown(). 1597*/ 1598typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1599struct sqlite3_mem_methods { 1600 void *(*xMalloc)(int); /* Memory allocation function */ 1601 void (*xFree)(void*); /* Free a prior allocation */ 1602 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1603 int (*xSize)(void*); /* Return the size of an allocation */ 1604 int (*xRoundup)(int); /* Round up request size to allocation size */ 1605 int (*xInit)(void*); /* Initialize the memory allocator */ 1606 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1607 void *pAppData; /* Argument to xInit() and xShutdown() */ 1608}; 1609 1610/* 1611** CAPI3REF: Configuration Options 1612** KEYWORDS: {configuration option} 1613** 1614** These constants are the available integer configuration options that 1615** can be passed as the first argument to the [sqlite3_config()] interface. 1616** 1617** New configuration options may be added in future releases of SQLite. 1618** Existing configuration options might be discontinued. Applications 1619** should check the return code from [sqlite3_config()] to make sure that 1620** the call worked. The [sqlite3_config()] interface will return a 1621** non-zero [error code] if a discontinued or unsupported configuration option 1622** is invoked. 1623** 1624** <dl> 1625** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1626** <dd>There are no arguments to this option. ^This option sets the 1627** [threading mode] to Single-thread. In other words, it disables 1628** all mutexing and puts SQLite into a mode where it can only be used 1629** by a single thread. ^If SQLite is compiled with 1630** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1631** it is not possible to change the [threading mode] from its default 1632** value of Single-thread and so [sqlite3_config()] will return 1633** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1634** configuration option.</dd> 1635** 1636** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1637** <dd>There are no arguments to this option. ^This option sets the 1638** [threading mode] to Multi-thread. In other words, it disables 1639** mutexing on [database connection] and [prepared statement] objects. 1640** The application is responsible for serializing access to 1641** [database connections] and [prepared statements]. But other mutexes 1642** are enabled so that SQLite will be safe to use in a multi-threaded 1643** environment as long as no two threads attempt to use the same 1644** [database connection] at the same time. ^If SQLite is compiled with 1645** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1646** it is not possible to set the Multi-thread [threading mode] and 1647** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1648** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1649** 1650** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1651** <dd>There are no arguments to this option. ^This option sets the 1652** [threading mode] to Serialized. In other words, this option enables 1653** all mutexes including the recursive 1654** mutexes on [database connection] and [prepared statement] objects. 1655** In this mode (which is the default when SQLite is compiled with 1656** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1657** to [database connections] and [prepared statements] so that the 1658** application is free to use the same [database connection] or the 1659** same [prepared statement] in different threads at the same time. 1660** ^If SQLite is compiled with 1661** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1662** it is not possible to set the Serialized [threading mode] and 1663** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1664** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1665** 1666** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1667** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1668** a pointer to an instance of the [sqlite3_mem_methods] structure. 1669** The argument specifies 1670** alternative low-level memory allocation routines to be used in place of 1671** the memory allocation routines built into SQLite.)^ ^SQLite makes 1672** its own private copy of the content of the [sqlite3_mem_methods] structure 1673** before the [sqlite3_config()] call returns.</dd> 1674** 1675** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1676** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1677** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1678** The [sqlite3_mem_methods] 1679** structure is filled with the currently defined memory allocation routines.)^ 1680** This option can be used to overload the default memory allocation 1681** routines with a wrapper that simulations memory allocation failure or 1682** tracks memory usage, for example. </dd> 1683** 1684** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1685** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1686** type int, interpreted as a boolean, which if true provides a hint to 1687** SQLite that it should avoid large memory allocations if possible. 1688** SQLite will run faster if it is free to make large memory allocations, 1689** but some application might prefer to run slower in exchange for 1690** guarantees about memory fragmentation that are possible if large 1691** allocations are avoided. This hint is normally off. 1692** </dd> 1693** 1694** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1695** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1696** interpreted as a boolean, which enables or disables the collection of 1697** memory allocation statistics. ^(When memory allocation statistics are 1698** disabled, the following SQLite interfaces become non-operational: 1699** <ul> 1700** <li> [sqlite3_memory_used()] 1701** <li> [sqlite3_memory_highwater()] 1702** <li> [sqlite3_soft_heap_limit64()] 1703** <li> [sqlite3_status64()] 1704** </ul>)^ 1705** ^Memory allocation statistics are enabled by default unless SQLite is 1706** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1707** allocation statistics are disabled by default. 1708** </dd> 1709** 1710** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1711** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1712** </dd> 1713** 1714** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1715** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1716** that SQLite can use for the database page cache with the default page 1717** cache implementation. 1718** This configuration option is a no-op if an application-define page 1719** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1720** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1721** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1722** and the number of cache lines (N). 1723** The sz argument should be the size of the largest database page 1724** (a power of two between 512 and 65536) plus some extra bytes for each 1725** page header. ^The number of extra bytes needed by the page header 1726** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1727** ^It is harmless, apart from the wasted memory, 1728** for the sz parameter to be larger than necessary. The pMem 1729** argument must be either a NULL pointer or a pointer to an 8-byte 1730** aligned block of memory of at least sz*N bytes, otherwise 1731** subsequent behavior is undefined. 1732** ^When pMem is not NULL, SQLite will strive to use the memory provided 1733** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1734** a page cache line is larger than sz bytes or if all of the pMem buffer 1735** is exhausted. 1736** ^If pMem is NULL and N is non-zero, then each database connection 1737** does an initial bulk allocation for page cache memory 1738** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1739** of -1024*N bytes if N is negative, . ^If additional 1740** page cache memory is needed beyond what is provided by the initial 1741** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1742** additional cache line. </dd> 1743** 1744** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1745** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1746** that SQLite will use for all of its dynamic memory allocation needs 1747** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1748** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1749** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1750** [SQLITE_ERROR] if invoked otherwise. 1751** ^There are three arguments to SQLITE_CONFIG_HEAP: 1752** An 8-byte aligned pointer to the memory, 1753** the number of bytes in the memory buffer, and the minimum allocation size. 1754** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1755** to using its default memory allocator (the system malloc() implementation), 1756** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1757** memory pointer is not NULL then the alternative memory 1758** allocator is engaged to handle all of SQLites memory allocation needs. 1759** The first pointer (the memory pointer) must be aligned to an 8-byte 1760** boundary or subsequent behavior of SQLite will be undefined. 1761** The minimum allocation size is capped at 2**12. Reasonable values 1762** for the minimum allocation size are 2**5 through 2**8.</dd> 1763** 1764** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1765** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1766** pointer to an instance of the [sqlite3_mutex_methods] structure. 1767** The argument specifies alternative low-level mutex routines to be used 1768** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1769** the content of the [sqlite3_mutex_methods] structure before the call to 1770** [sqlite3_config()] returns. ^If SQLite is compiled with 1771** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1772** the entire mutexing subsystem is omitted from the build and hence calls to 1773** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1774** return [SQLITE_ERROR].</dd> 1775** 1776** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1777** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1778** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1779** [sqlite3_mutex_methods] 1780** structure is filled with the currently defined mutex routines.)^ 1781** This option can be used to overload the default mutex allocation 1782** routines with a wrapper used to track mutex usage for performance 1783** profiling or testing, for example. ^If SQLite is compiled with 1784** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1785** the entire mutexing subsystem is omitted from the build and hence calls to 1786** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1787** return [SQLITE_ERROR].</dd> 1788** 1789** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1790** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1791** the default size of lookaside memory on each [database connection]. 1792** The first argument is the 1793** size of each lookaside buffer slot and the second is the number of 1794** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1795** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1796** option to [sqlite3_db_config()] can be used to change the lookaside 1797** configuration on individual connections.)^ </dd> 1798** 1799** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1800** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1801** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1802** the interface to a custom page cache implementation.)^ 1803** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1804** 1805** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1806** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1807** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1808** the current page cache implementation into that object.)^ </dd> 1809** 1810** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1811** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1812** global [error log]. 1813** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1814** function with a call signature of void(*)(void*,int,const char*), 1815** and a pointer to void. ^If the function pointer is not NULL, it is 1816** invoked by [sqlite3_log()] to process each logging event. ^If the 1817** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1818** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1819** passed through as the first parameter to the application-defined logger 1820** function whenever that function is invoked. ^The second parameter to 1821** the logger function is a copy of the first parameter to the corresponding 1822** [sqlite3_log()] call and is intended to be a [result code] or an 1823** [extended result code]. ^The third parameter passed to the logger is 1824** log message after formatting via [sqlite3_snprintf()]. 1825** The SQLite logging interface is not reentrant; the logger function 1826** supplied by the application must not invoke any SQLite interface. 1827** In a multi-threaded application, the application-defined logger 1828** function must be threadsafe. </dd> 1829** 1830** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1831** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1832** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1833** then URI handling is globally disabled.)^ ^If URI handling is globally 1834** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1835** [sqlite3_open16()] or 1836** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1837** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1838** connection is opened. ^If it is globally disabled, filenames are 1839** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1840** database connection is opened. ^(By default, URI handling is globally 1841** disabled. The default value may be changed by compiling with the 1842** [SQLITE_USE_URI] symbol defined.)^ 1843** 1844** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1845** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1846** argument which is interpreted as a boolean in order to enable or disable 1847** the use of covering indices for full table scans in the query optimizer. 1848** ^The default setting is determined 1849** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1850** if that compile-time option is omitted. 1851** The ability to disable the use of covering indices for full table scans 1852** is because some incorrectly coded legacy applications might malfunction 1853** when the optimization is enabled. Providing the ability to 1854** disable the optimization allows the older, buggy application code to work 1855** without change even with newer versions of SQLite. 1856** 1857** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1858** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1859** <dd> These options are obsolete and should not be used by new code. 1860** They are retained for backwards compatibility but are now no-ops. 1861** </dd> 1862** 1863** [[SQLITE_CONFIG_SQLLOG]] 1864** <dt>SQLITE_CONFIG_SQLLOG 1865** <dd>This option is only available if sqlite is compiled with the 1866** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1867** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1868** The second should be of type (void*). The callback is invoked by the library 1869** in three separate circumstances, identified by the value passed as the 1870** fourth parameter. If the fourth parameter is 0, then the database connection 1871** passed as the second argument has just been opened. The third argument 1872** points to a buffer containing the name of the main database file. If the 1873** fourth parameter is 1, then the SQL statement that the third parameter 1874** points to has just been executed. Or, if the fourth parameter is 2, then 1875** the connection being passed as the second parameter is being closed. The 1876** third parameter is passed NULL In this case. An example of using this 1877** configuration option can be seen in the "test_sqllog.c" source file in 1878** the canonical SQLite source tree.</dd> 1879** 1880** [[SQLITE_CONFIG_MMAP_SIZE]] 1881** <dt>SQLITE_CONFIG_MMAP_SIZE 1882** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1883** that are the default mmap size limit (the default setting for 1884** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1885** ^The default setting can be overridden by each database connection using 1886** either the [PRAGMA mmap_size] command, or by using the 1887** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1888** will be silently truncated if necessary so that it does not exceed the 1889** compile-time maximum mmap size set by the 1890** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1891** ^If either argument to this option is negative, then that argument is 1892** changed to its compile-time default. 1893** 1894** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1895** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1896** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1897** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1898** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1899** that specifies the maximum size of the created heap. 1900** 1901** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1902** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1903** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1904** is a pointer to an integer and writes into that integer the number of extra 1905** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1906** The amount of extra space required can change depending on the compiler, 1907** target platform, and SQLite version. 1908** 1909** [[SQLITE_CONFIG_PMASZ]] 1910** <dt>SQLITE_CONFIG_PMASZ 1911** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1912** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1913** sorter to that integer. The default minimum PMA Size is set by the 1914** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1915** to help with sort operations when multithreaded sorting 1916** is enabled (using the [PRAGMA threads] command) and the amount of content 1917** to be sorted exceeds the page size times the minimum of the 1918** [PRAGMA cache_size] setting and this value. 1919** 1920** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1921** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1922** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1923** becomes the [statement journal] spill-to-disk threshold. 1924** [Statement journals] are held in memory until their size (in bytes) 1925** exceeds this threshold, at which point they are written to disk. 1926** Or if the threshold is -1, statement journals are always held 1927** exclusively in memory. 1928** Since many statement journals never become large, setting the spill 1929** threshold to a value such as 64KiB can greatly reduce the amount of 1930** I/O required to support statement rollback. 1931** The default value for this setting is controlled by the 1932** [SQLITE_STMTJRNL_SPILL] compile-time option. 1933** 1934** [[SQLITE_CONFIG_SORTERREF_SIZE]] 1935** <dt>SQLITE_CONFIG_SORTERREF_SIZE 1936** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 1937** of type (int) - the new value of the sorter-reference size threshold. 1938** Usually, when SQLite uses an external sort to order records according 1939** to an ORDER BY clause, all fields required by the caller are present in the 1940** sorted records. However, if SQLite determines based on the declared type 1941** of a table column that its values are likely to be very large - larger 1942** than the configured sorter-reference size threshold - then a reference 1943** is stored in each sorted record and the required column values loaded 1944** from the database as records are returned in sorted order. The default 1945** value for this option is to never use this optimization. Specifying a 1946** negative value for this option restores the default behaviour. 1947** This option is only available if SQLite is compiled with the 1948** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 1949** </dl> 1950*/ 1951#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1952#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1953#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1954#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1955#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1956#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1957#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1958#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1959#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1960#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1961#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1962/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1963#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1964#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1965#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1966#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1967#define SQLITE_CONFIG_URI 17 /* int */ 1968#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1969#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1970#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1971#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1972#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1973#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1974#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1975#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1976#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1977#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1978#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 1979 1980/* 1981** CAPI3REF: Database Connection Configuration Options 1982** 1983** These constants are the available integer configuration options that 1984** can be passed as the second argument to the [sqlite3_db_config()] interface. 1985** 1986** New configuration options may be added in future releases of SQLite. 1987** Existing configuration options might be discontinued. Applications 1988** should check the return code from [sqlite3_db_config()] to make sure that 1989** the call worked. ^The [sqlite3_db_config()] interface will return a 1990** non-zero [error code] if a discontinued or unsupported configuration option 1991** is invoked. 1992** 1993** <dl> 1994** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1995** <dd> ^This option takes three additional arguments that determine the 1996** [lookaside memory allocator] configuration for the [database connection]. 1997** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1998** pointer to a memory buffer to use for lookaside memory. 1999** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2000** may be NULL in which case SQLite will allocate the 2001** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2002** size of each lookaside buffer slot. ^The third argument is the number of 2003** slots. The size of the buffer in the first argument must be greater than 2004** or equal to the product of the second and third arguments. The buffer 2005** must be aligned to an 8-byte boundary. ^If the second argument to 2006** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2007** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2008** configuration for a database connection can only be changed when that 2009** connection is not currently using lookaside memory, or in other words 2010** when the "current value" returned by 2011** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2012** Any attempt to change the lookaside memory configuration when lookaside 2013** memory is in use leaves the configuration unchanged and returns 2014** [SQLITE_BUSY].)^</dd> 2015** 2016** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2017** <dd> ^This option is used to enable or disable the enforcement of 2018** [foreign key constraints]. There should be two additional arguments. 2019** The first argument is an integer which is 0 to disable FK enforcement, 2020** positive to enable FK enforcement or negative to leave FK enforcement 2021** unchanged. The second parameter is a pointer to an integer into which 2022** is written 0 or 1 to indicate whether FK enforcement is off or on 2023** following this call. The second parameter may be a NULL pointer, in 2024** which case the FK enforcement setting is not reported back. </dd> 2025** 2026** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2027** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2028** There should be two additional arguments. 2029** The first argument is an integer which is 0 to disable triggers, 2030** positive to enable triggers or negative to leave the setting unchanged. 2031** The second parameter is a pointer to an integer into which 2032** is written 0 or 1 to indicate whether triggers are disabled or enabled 2033** following this call. The second parameter may be a NULL pointer, in 2034** which case the trigger setting is not reported back. </dd> 2035** 2036** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2037** <dd> ^This option is used to enable or disable the two-argument 2038** version of the [fts3_tokenizer()] function which is part of the 2039** [FTS3] full-text search engine extension. 2040** There should be two additional arguments. 2041** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2042** positive to enable fts3_tokenizer() or negative to leave the setting 2043** unchanged. 2044** The second parameter is a pointer to an integer into which 2045** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2046** following this call. The second parameter may be a NULL pointer, in 2047** which case the new setting is not reported back. </dd> 2048** 2049** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2050** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2051** interface independently of the [load_extension()] SQL function. 2052** The [sqlite3_enable_load_extension()] API enables or disables both the 2053** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2054** There should be two additional arguments. 2055** When the first argument to this interface is 1, then only the C-API is 2056** enabled and the SQL function remains disabled. If the first argument to 2057** this interface is 0, then both the C-API and the SQL function are disabled. 2058** If the first argument is -1, then no changes are made to state of either the 2059** C-API or the SQL function. 2060** The second parameter is a pointer to an integer into which 2061** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2062** is disabled or enabled following this call. The second parameter may 2063** be a NULL pointer, in which case the new setting is not reported back. 2064** </dd> 2065** 2066** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2067** <dd> ^This option is used to change the name of the "main" database 2068** schema. ^The sole argument is a pointer to a constant UTF8 string 2069** which will become the new schema name in place of "main". ^SQLite 2070** does not make a copy of the new main schema name string, so the application 2071** must ensure that the argument passed into this DBCONFIG option is unchanged 2072** until after the database connection closes. 2073** </dd> 2074** 2075** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2076** <dd> Usually, when a database in wal mode is closed or detached from a 2077** database handle, SQLite checks if this will mean that there are now no 2078** connections at all to the database. If so, it performs a checkpoint 2079** operation before closing the connection. This option may be used to 2080** override this behaviour. The first parameter passed to this operation 2081** is an integer - positive to disable checkpoints-on-close, or zero (the 2082** default) to enable them, and negative to leave the setting unchanged. 2083** The second parameter is a pointer to an integer 2084** into which is written 0 or 1 to indicate whether checkpoints-on-close 2085** have been disabled - 0 if they are not disabled, 1 if they are. 2086** </dd> 2087** 2088** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2089** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2090** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2091** a single SQL query statement will always use the same algorithm regardless 2092** of values of [bound parameters].)^ The QPSG disables some query optimizations 2093** that look at the values of bound parameters, which can make some queries 2094** slower. But the QPSG has the advantage of more predictable behavior. With 2095** the QPSG active, SQLite will always use the same query plan in the field as 2096** was used during testing in the lab. 2097** The first argument to this setting is an integer which is 0 to disable 2098** the QPSG, positive to enable QPSG, or negative to leave the setting 2099** unchanged. The second parameter is a pointer to an integer into which 2100** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2101** following this call. 2102** </dd> 2103** 2104** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2105** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2106** include output for any operations performed by trigger programs. This 2107** option is used to set or clear (the default) a flag that governs this 2108** behavior. The first parameter passed to this operation is an integer - 2109** positive to enable output for trigger programs, or zero to disable it, 2110** or negative to leave the setting unchanged. 2111** The second parameter is a pointer to an integer into which is written 2112** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2113** it is not disabled, 1 if it is. 2114** </dd> 2115** </dl> 2116*/ 2117#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2118#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2119#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2120#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2121#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2122#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2123#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2124#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2125#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2126#define SQLITE_DBCONFIG_MAX 1008 /* Largest DBCONFIG */ 2127 2128/* 2129** CAPI3REF: Enable Or Disable Extended Result Codes 2130** METHOD: sqlite3 2131** 2132** ^The sqlite3_extended_result_codes() routine enables or disables the 2133** [extended result codes] feature of SQLite. ^The extended result 2134** codes are disabled by default for historical compatibility. 2135*/ 2136int sqlite3_extended_result_codes(sqlite3*, int onoff); 2137 2138/* 2139** CAPI3REF: Last Insert Rowid 2140** METHOD: sqlite3 2141** 2142** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2143** has a unique 64-bit signed 2144** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2145** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2146** names are not also used by explicitly declared columns. ^If 2147** the table has a column of type [INTEGER PRIMARY KEY] then that column 2148** is another alias for the rowid. 2149** 2150** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2151** the most recent successful [INSERT] into a rowid table or [virtual table] 2152** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2153** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2154** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2155** zero. 2156** 2157** As well as being set automatically as rows are inserted into database 2158** tables, the value returned by this function may be set explicitly by 2159** [sqlite3_set_last_insert_rowid()] 2160** 2161** Some virtual table implementations may INSERT rows into rowid tables as 2162** part of committing a transaction (e.g. to flush data accumulated in memory 2163** to disk). In this case subsequent calls to this function return the rowid 2164** associated with these internal INSERT operations, which leads to 2165** unintuitive results. Virtual table implementations that do write to rowid 2166** tables in this way can avoid this problem by restoring the original 2167** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2168** control to the user. 2169** 2170** ^(If an [INSERT] occurs within a trigger then this routine will 2171** return the [rowid] of the inserted row as long as the trigger is 2172** running. Once the trigger program ends, the value returned 2173** by this routine reverts to what it was before the trigger was fired.)^ 2174** 2175** ^An [INSERT] that fails due to a constraint violation is not a 2176** successful [INSERT] and does not change the value returned by this 2177** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2178** and INSERT OR ABORT make no changes to the return value of this 2179** routine when their insertion fails. ^(When INSERT OR REPLACE 2180** encounters a constraint violation, it does not fail. The 2181** INSERT continues to completion after deleting rows that caused 2182** the constraint problem so INSERT OR REPLACE will always change 2183** the return value of this interface.)^ 2184** 2185** ^For the purposes of this routine, an [INSERT] is considered to 2186** be successful even if it is subsequently rolled back. 2187** 2188** This function is accessible to SQL statements via the 2189** [last_insert_rowid() SQL function]. 2190** 2191** If a separate thread performs a new [INSERT] on the same 2192** database connection while the [sqlite3_last_insert_rowid()] 2193** function is running and thus changes the last insert [rowid], 2194** then the value returned by [sqlite3_last_insert_rowid()] is 2195** unpredictable and might not equal either the old or the new 2196** last insert [rowid]. 2197*/ 2198sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2199 2200/* 2201** CAPI3REF: Set the Last Insert Rowid value. 2202** METHOD: sqlite3 2203** 2204** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2205** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2206** without inserting a row into the database. 2207*/ 2208void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2209 2210/* 2211** CAPI3REF: Count The Number Of Rows Modified 2212** METHOD: sqlite3 2213** 2214** ^This function returns the number of rows modified, inserted or 2215** deleted by the most recently completed INSERT, UPDATE or DELETE 2216** statement on the database connection specified by the only parameter. 2217** ^Executing any other type of SQL statement does not modify the value 2218** returned by this function. 2219** 2220** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2221** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2222** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2223** 2224** Changes to a view that are intercepted by 2225** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2226** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2227** DELETE statement run on a view is always zero. Only changes made to real 2228** tables are counted. 2229** 2230** Things are more complicated if the sqlite3_changes() function is 2231** executed while a trigger program is running. This may happen if the 2232** program uses the [changes() SQL function], or if some other callback 2233** function invokes sqlite3_changes() directly. Essentially: 2234** 2235** <ul> 2236** <li> ^(Before entering a trigger program the value returned by 2237** sqlite3_changes() function is saved. After the trigger program 2238** has finished, the original value is restored.)^ 2239** 2240** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2241** statement sets the value returned by sqlite3_changes() 2242** upon completion as normal. Of course, this value will not include 2243** any changes performed by sub-triggers, as the sqlite3_changes() 2244** value will be saved and restored after each sub-trigger has run.)^ 2245** </ul> 2246** 2247** ^This means that if the changes() SQL function (or similar) is used 2248** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2249** returns the value as set when the calling statement began executing. 2250** ^If it is used by the second or subsequent such statement within a trigger 2251** program, the value returned reflects the number of rows modified by the 2252** previous INSERT, UPDATE or DELETE statement within the same trigger. 2253** 2254** See also the [sqlite3_total_changes()] interface, the 2255** [count_changes pragma], and the [changes() SQL function]. 2256** 2257** If a separate thread makes changes on the same database connection 2258** while [sqlite3_changes()] is running then the value returned 2259** is unpredictable and not meaningful. 2260*/ 2261int sqlite3_changes(sqlite3*); 2262 2263/* 2264** CAPI3REF: Total Number Of Rows Modified 2265** METHOD: sqlite3 2266** 2267** ^This function returns the total number of rows inserted, modified or 2268** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2269** since the database connection was opened, including those executed as 2270** part of trigger programs. ^Executing any other type of SQL statement 2271** does not affect the value returned by sqlite3_total_changes(). 2272** 2273** ^Changes made as part of [foreign key actions] are included in the 2274** count, but those made as part of REPLACE constraint resolution are 2275** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2276** are not counted. 2277** 2278** See also the [sqlite3_changes()] interface, the 2279** [count_changes pragma], and the [total_changes() SQL function]. 2280** 2281** If a separate thread makes changes on the same database connection 2282** while [sqlite3_total_changes()] is running then the value 2283** returned is unpredictable and not meaningful. 2284*/ 2285int sqlite3_total_changes(sqlite3*); 2286 2287/* 2288** CAPI3REF: Interrupt A Long-Running Query 2289** METHOD: sqlite3 2290** 2291** ^This function causes any pending database operation to abort and 2292** return at its earliest opportunity. This routine is typically 2293** called in response to a user action such as pressing "Cancel" 2294** or Ctrl-C where the user wants a long query operation to halt 2295** immediately. 2296** 2297** ^It is safe to call this routine from a thread different from the 2298** thread that is currently running the database operation. But it 2299** is not safe to call this routine with a [database connection] that 2300** is closed or might close before sqlite3_interrupt() returns. 2301** 2302** ^If an SQL operation is very nearly finished at the time when 2303** sqlite3_interrupt() is called, then it might not have an opportunity 2304** to be interrupted and might continue to completion. 2305** 2306** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2307** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2308** that is inside an explicit transaction, then the entire transaction 2309** will be rolled back automatically. 2310** 2311** ^The sqlite3_interrupt(D) call is in effect until all currently running 2312** SQL statements on [database connection] D complete. ^Any new SQL statements 2313** that are started after the sqlite3_interrupt() call and before the 2314** running statements reaches zero are interrupted as if they had been 2315** running prior to the sqlite3_interrupt() call. ^New SQL statements 2316** that are started after the running statement count reaches zero are 2317** not effected by the sqlite3_interrupt(). 2318** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2319** SQL statements is a no-op and has no effect on SQL statements 2320** that are started after the sqlite3_interrupt() call returns. 2321*/ 2322void sqlite3_interrupt(sqlite3*); 2323 2324/* 2325** CAPI3REF: Determine If An SQL Statement Is Complete 2326** 2327** These routines are useful during command-line input to determine if the 2328** currently entered text seems to form a complete SQL statement or 2329** if additional input is needed before sending the text into 2330** SQLite for parsing. ^These routines return 1 if the input string 2331** appears to be a complete SQL statement. ^A statement is judged to be 2332** complete if it ends with a semicolon token and is not a prefix of a 2333** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2334** string literals or quoted identifier names or comments are not 2335** independent tokens (they are part of the token in which they are 2336** embedded) and thus do not count as a statement terminator. ^Whitespace 2337** and comments that follow the final semicolon are ignored. 2338** 2339** ^These routines return 0 if the statement is incomplete. ^If a 2340** memory allocation fails, then SQLITE_NOMEM is returned. 2341** 2342** ^These routines do not parse the SQL statements thus 2343** will not detect syntactically incorrect SQL. 2344** 2345** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2346** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2347** automatically by sqlite3_complete16(). If that initialization fails, 2348** then the return value from sqlite3_complete16() will be non-zero 2349** regardless of whether or not the input SQL is complete.)^ 2350** 2351** The input to [sqlite3_complete()] must be a zero-terminated 2352** UTF-8 string. 2353** 2354** The input to [sqlite3_complete16()] must be a zero-terminated 2355** UTF-16 string in native byte order. 2356*/ 2357int sqlite3_complete(const char *sql); 2358int sqlite3_complete16(const void *sql); 2359 2360/* 2361** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2362** KEYWORDS: {busy-handler callback} {busy handler} 2363** METHOD: sqlite3 2364** 2365** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2366** that might be invoked with argument P whenever 2367** an attempt is made to access a database table associated with 2368** [database connection] D when another thread 2369** or process has the table locked. 2370** The sqlite3_busy_handler() interface is used to implement 2371** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2372** 2373** ^If the busy callback is NULL, then [SQLITE_BUSY] 2374** is returned immediately upon encountering the lock. ^If the busy callback 2375** is not NULL, then the callback might be invoked with two arguments. 2376** 2377** ^The first argument to the busy handler is a copy of the void* pointer which 2378** is the third argument to sqlite3_busy_handler(). ^The second argument to 2379** the busy handler callback is the number of times that the busy handler has 2380** been invoked previously for the same locking event. ^If the 2381** busy callback returns 0, then no additional attempts are made to 2382** access the database and [SQLITE_BUSY] is returned 2383** to the application. 2384** ^If the callback returns non-zero, then another attempt 2385** is made to access the database and the cycle repeats. 2386** 2387** The presence of a busy handler does not guarantee that it will be invoked 2388** when there is lock contention. ^If SQLite determines that invoking the busy 2389** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2390** to the application instead of invoking the 2391** busy handler. 2392** Consider a scenario where one process is holding a read lock that 2393** it is trying to promote to a reserved lock and 2394** a second process is holding a reserved lock that it is trying 2395** to promote to an exclusive lock. The first process cannot proceed 2396** because it is blocked by the second and the second process cannot 2397** proceed because it is blocked by the first. If both processes 2398** invoke the busy handlers, neither will make any progress. Therefore, 2399** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2400** will induce the first process to release its read lock and allow 2401** the second process to proceed. 2402** 2403** ^The default busy callback is NULL. 2404** 2405** ^(There can only be a single busy handler defined for each 2406** [database connection]. Setting a new busy handler clears any 2407** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2408** or evaluating [PRAGMA busy_timeout=N] will change the 2409** busy handler and thus clear any previously set busy handler. 2410** 2411** The busy callback should not take any actions which modify the 2412** database connection that invoked the busy handler. In other words, 2413** the busy handler is not reentrant. Any such actions 2414** result in undefined behavior. 2415** 2416** A busy handler must not close the database connection 2417** or [prepared statement] that invoked the busy handler. 2418*/ 2419int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2420 2421/* 2422** CAPI3REF: Set A Busy Timeout 2423** METHOD: sqlite3 2424** 2425** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2426** for a specified amount of time when a table is locked. ^The handler 2427** will sleep multiple times until at least "ms" milliseconds of sleeping 2428** have accumulated. ^After at least "ms" milliseconds of sleeping, 2429** the handler returns 0 which causes [sqlite3_step()] to return 2430** [SQLITE_BUSY]. 2431** 2432** ^Calling this routine with an argument less than or equal to zero 2433** turns off all busy handlers. 2434** 2435** ^(There can only be a single busy handler for a particular 2436** [database connection] at any given moment. If another busy handler 2437** was defined (using [sqlite3_busy_handler()]) prior to calling 2438** this routine, that other busy handler is cleared.)^ 2439** 2440** See also: [PRAGMA busy_timeout] 2441*/ 2442int sqlite3_busy_timeout(sqlite3*, int ms); 2443 2444/* 2445** CAPI3REF: Convenience Routines For Running Queries 2446** METHOD: sqlite3 2447** 2448** This is a legacy interface that is preserved for backwards compatibility. 2449** Use of this interface is not recommended. 2450** 2451** Definition: A <b>result table</b> is memory data structure created by the 2452** [sqlite3_get_table()] interface. A result table records the 2453** complete query results from one or more queries. 2454** 2455** The table conceptually has a number of rows and columns. But 2456** these numbers are not part of the result table itself. These 2457** numbers are obtained separately. Let N be the number of rows 2458** and M be the number of columns. 2459** 2460** A result table is an array of pointers to zero-terminated UTF-8 strings. 2461** There are (N+1)*M elements in the array. The first M pointers point 2462** to zero-terminated strings that contain the names of the columns. 2463** The remaining entries all point to query results. NULL values result 2464** in NULL pointers. All other values are in their UTF-8 zero-terminated 2465** string representation as returned by [sqlite3_column_text()]. 2466** 2467** A result table might consist of one or more memory allocations. 2468** It is not safe to pass a result table directly to [sqlite3_free()]. 2469** A result table should be deallocated using [sqlite3_free_table()]. 2470** 2471** ^(As an example of the result table format, suppose a query result 2472** is as follows: 2473** 2474** <blockquote><pre> 2475** Name | Age 2476** ----------------------- 2477** Alice | 43 2478** Bob | 28 2479** Cindy | 21 2480** </pre></blockquote> 2481** 2482** There are two column (M==2) and three rows (N==3). Thus the 2483** result table has 8 entries. Suppose the result table is stored 2484** in an array names azResult. Then azResult holds this content: 2485** 2486** <blockquote><pre> 2487** azResult[0] = "Name"; 2488** azResult[1] = "Age"; 2489** azResult[2] = "Alice"; 2490** azResult[3] = "43"; 2491** azResult[4] = "Bob"; 2492** azResult[5] = "28"; 2493** azResult[6] = "Cindy"; 2494** azResult[7] = "21"; 2495** </pre></blockquote>)^ 2496** 2497** ^The sqlite3_get_table() function evaluates one or more 2498** semicolon-separated SQL statements in the zero-terminated UTF-8 2499** string of its 2nd parameter and returns a result table to the 2500** pointer given in its 3rd parameter. 2501** 2502** After the application has finished with the result from sqlite3_get_table(), 2503** it must pass the result table pointer to sqlite3_free_table() in order to 2504** release the memory that was malloced. Because of the way the 2505** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2506** function must not try to call [sqlite3_free()] directly. Only 2507** [sqlite3_free_table()] is able to release the memory properly and safely. 2508** 2509** The sqlite3_get_table() interface is implemented as a wrapper around 2510** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2511** to any internal data structures of SQLite. It uses only the public 2512** interface defined here. As a consequence, errors that occur in the 2513** wrapper layer outside of the internal [sqlite3_exec()] call are not 2514** reflected in subsequent calls to [sqlite3_errcode()] or 2515** [sqlite3_errmsg()]. 2516*/ 2517int sqlite3_get_table( 2518 sqlite3 *db, /* An open database */ 2519 const char *zSql, /* SQL to be evaluated */ 2520 char ***pazResult, /* Results of the query */ 2521 int *pnRow, /* Number of result rows written here */ 2522 int *pnColumn, /* Number of result columns written here */ 2523 char **pzErrmsg /* Error msg written here */ 2524); 2525void sqlite3_free_table(char **result); 2526 2527/* 2528** CAPI3REF: Formatted String Printing Functions 2529** 2530** These routines are work-alikes of the "printf()" family of functions 2531** from the standard C library. 2532** These routines understand most of the common formatting options from 2533** the standard library printf() 2534** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2535** See the [built-in printf()] documentation for details. 2536** 2537** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2538** results into memory obtained from [sqlite3_malloc64()]. 2539** The strings returned by these two routines should be 2540** released by [sqlite3_free()]. ^Both routines return a 2541** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2542** memory to hold the resulting string. 2543** 2544** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2545** the standard C library. The result is written into the 2546** buffer supplied as the second parameter whose size is given by 2547** the first parameter. Note that the order of the 2548** first two parameters is reversed from snprintf().)^ This is an 2549** historical accident that cannot be fixed without breaking 2550** backwards compatibility. ^(Note also that sqlite3_snprintf() 2551** returns a pointer to its buffer instead of the number of 2552** characters actually written into the buffer.)^ We admit that 2553** the number of characters written would be a more useful return 2554** value but we cannot change the implementation of sqlite3_snprintf() 2555** now without breaking compatibility. 2556** 2557** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2558** guarantees that the buffer is always zero-terminated. ^The first 2559** parameter "n" is the total size of the buffer, including space for 2560** the zero terminator. So the longest string that can be completely 2561** written will be n-1 characters. 2562** 2563** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2564** 2565** See also: [built-in printf()], [printf() SQL function] 2566*/ 2567char *sqlite3_mprintf(const char*,...); 2568char *sqlite3_vmprintf(const char*, va_list); 2569char *sqlite3_snprintf(int,char*,const char*, ...); 2570char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2571 2572/* 2573** CAPI3REF: Memory Allocation Subsystem 2574** 2575** The SQLite core uses these three routines for all of its own 2576** internal memory allocation needs. "Core" in the previous sentence 2577** does not include operating-system specific VFS implementation. The 2578** Windows VFS uses native malloc() and free() for some operations. 2579** 2580** ^The sqlite3_malloc() routine returns a pointer to a block 2581** of memory at least N bytes in length, where N is the parameter. 2582** ^If sqlite3_malloc() is unable to obtain sufficient free 2583** memory, it returns a NULL pointer. ^If the parameter N to 2584** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2585** a NULL pointer. 2586** 2587** ^The sqlite3_malloc64(N) routine works just like 2588** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2589** of a signed 32-bit integer. 2590** 2591** ^Calling sqlite3_free() with a pointer previously returned 2592** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2593** that it might be reused. ^The sqlite3_free() routine is 2594** a no-op if is called with a NULL pointer. Passing a NULL pointer 2595** to sqlite3_free() is harmless. After being freed, memory 2596** should neither be read nor written. Even reading previously freed 2597** memory might result in a segmentation fault or other severe error. 2598** Memory corruption, a segmentation fault, or other severe error 2599** might result if sqlite3_free() is called with a non-NULL pointer that 2600** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2601** 2602** ^The sqlite3_realloc(X,N) interface attempts to resize a 2603** prior memory allocation X to be at least N bytes. 2604** ^If the X parameter to sqlite3_realloc(X,N) 2605** is a NULL pointer then its behavior is identical to calling 2606** sqlite3_malloc(N). 2607** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2608** negative then the behavior is exactly the same as calling 2609** sqlite3_free(X). 2610** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2611** of at least N bytes in size or NULL if insufficient memory is available. 2612** ^If M is the size of the prior allocation, then min(N,M) bytes 2613** of the prior allocation are copied into the beginning of buffer returned 2614** by sqlite3_realloc(X,N) and the prior allocation is freed. 2615** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2616** prior allocation is not freed. 2617** 2618** ^The sqlite3_realloc64(X,N) interfaces works the same as 2619** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2620** of a 32-bit signed integer. 2621** 2622** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2623** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2624** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2625** ^The value returned by sqlite3_msize(X) might be larger than the number 2626** of bytes requested when X was allocated. ^If X is a NULL pointer then 2627** sqlite3_msize(X) returns zero. If X points to something that is not 2628** the beginning of memory allocation, or if it points to a formerly 2629** valid memory allocation that has now been freed, then the behavior 2630** of sqlite3_msize(X) is undefined and possibly harmful. 2631** 2632** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2633** sqlite3_malloc64(), and sqlite3_realloc64() 2634** is always aligned to at least an 8 byte boundary, or to a 2635** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2636** option is used. 2637** 2638** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2639** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2640** implementation of these routines to be omitted. That capability 2641** is no longer provided. Only built-in memory allocators can be used. 2642** 2643** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2644** the system malloc() and free() directly when converting 2645** filenames between the UTF-8 encoding used by SQLite 2646** and whatever filename encoding is used by the particular Windows 2647** installation. Memory allocation errors were detected, but 2648** they were reported back as [SQLITE_CANTOPEN] or 2649** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2650** 2651** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2652** must be either NULL or else pointers obtained from a prior 2653** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2654** not yet been released. 2655** 2656** The application must not read or write any part of 2657** a block of memory after it has been released using 2658** [sqlite3_free()] or [sqlite3_realloc()]. 2659*/ 2660void *sqlite3_malloc(int); 2661void *sqlite3_malloc64(sqlite3_uint64); 2662void *sqlite3_realloc(void*, int); 2663void *sqlite3_realloc64(void*, sqlite3_uint64); 2664void sqlite3_free(void*); 2665sqlite3_uint64 sqlite3_msize(void*); 2666 2667/* 2668** CAPI3REF: Memory Allocator Statistics 2669** 2670** SQLite provides these two interfaces for reporting on the status 2671** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2672** routines, which form the built-in memory allocation subsystem. 2673** 2674** ^The [sqlite3_memory_used()] routine returns the number of bytes 2675** of memory currently outstanding (malloced but not freed). 2676** ^The [sqlite3_memory_highwater()] routine returns the maximum 2677** value of [sqlite3_memory_used()] since the high-water mark 2678** was last reset. ^The values returned by [sqlite3_memory_used()] and 2679** [sqlite3_memory_highwater()] include any overhead 2680** added by SQLite in its implementation of [sqlite3_malloc()], 2681** but not overhead added by the any underlying system library 2682** routines that [sqlite3_malloc()] may call. 2683** 2684** ^The memory high-water mark is reset to the current value of 2685** [sqlite3_memory_used()] if and only if the parameter to 2686** [sqlite3_memory_highwater()] is true. ^The value returned 2687** by [sqlite3_memory_highwater(1)] is the high-water mark 2688** prior to the reset. 2689*/ 2690sqlite3_int64 sqlite3_memory_used(void); 2691sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2692 2693/* 2694** CAPI3REF: Pseudo-Random Number Generator 2695** 2696** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2697** select random [ROWID | ROWIDs] when inserting new records into a table that 2698** already uses the largest possible [ROWID]. The PRNG is also used for 2699** the build-in random() and randomblob() SQL functions. This interface allows 2700** applications to access the same PRNG for other purposes. 2701** 2702** ^A call to this routine stores N bytes of randomness into buffer P. 2703** ^The P parameter can be a NULL pointer. 2704** 2705** ^If this routine has not been previously called or if the previous 2706** call had N less than one or a NULL pointer for P, then the PRNG is 2707** seeded using randomness obtained from the xRandomness method of 2708** the default [sqlite3_vfs] object. 2709** ^If the previous call to this routine had an N of 1 or more and a 2710** non-NULL P then the pseudo-randomness is generated 2711** internally and without recourse to the [sqlite3_vfs] xRandomness 2712** method. 2713*/ 2714void sqlite3_randomness(int N, void *P); 2715 2716/* 2717** CAPI3REF: Compile-Time Authorization Callbacks 2718** METHOD: sqlite3 2719** KEYWORDS: {authorizer callback} 2720** 2721** ^This routine registers an authorizer callback with a particular 2722** [database connection], supplied in the first argument. 2723** ^The authorizer callback is invoked as SQL statements are being compiled 2724** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2725** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2726** and [sqlite3_prepare16_v3()]. ^At various 2727** points during the compilation process, as logic is being created 2728** to perform various actions, the authorizer callback is invoked to 2729** see if those actions are allowed. ^The authorizer callback should 2730** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2731** specific action but allow the SQL statement to continue to be 2732** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2733** rejected with an error. ^If the authorizer callback returns 2734** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2735** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2736** the authorizer will fail with an error message. 2737** 2738** When the callback returns [SQLITE_OK], that means the operation 2739** requested is ok. ^When the callback returns [SQLITE_DENY], the 2740** [sqlite3_prepare_v2()] or equivalent call that triggered the 2741** authorizer will fail with an error message explaining that 2742** access is denied. 2743** 2744** ^The first parameter to the authorizer callback is a copy of the third 2745** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2746** to the callback is an integer [SQLITE_COPY | action code] that specifies 2747** the particular action to be authorized. ^The third through sixth parameters 2748** to the callback are either NULL pointers or zero-terminated strings 2749** that contain additional details about the action to be authorized. 2750** Applications must always be prepared to encounter a NULL pointer in any 2751** of the third through the sixth parameters of the authorization callback. 2752** 2753** ^If the action code is [SQLITE_READ] 2754** and the callback returns [SQLITE_IGNORE] then the 2755** [prepared statement] statement is constructed to substitute 2756** a NULL value in place of the table column that would have 2757** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2758** return can be used to deny an untrusted user access to individual 2759** columns of a table. 2760** ^When a table is referenced by a [SELECT] but no column values are 2761** extracted from that table (for example in a query like 2762** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2763** is invoked once for that table with a column name that is an empty string. 2764** ^If the action code is [SQLITE_DELETE] and the callback returns 2765** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2766** [truncate optimization] is disabled and all rows are deleted individually. 2767** 2768** An authorizer is used when [sqlite3_prepare | preparing] 2769** SQL statements from an untrusted source, to ensure that the SQL statements 2770** do not try to access data they are not allowed to see, or that they do not 2771** try to execute malicious statements that damage the database. For 2772** example, an application may allow a user to enter arbitrary 2773** SQL queries for evaluation by a database. But the application does 2774** not want the user to be able to make arbitrary changes to the 2775** database. An authorizer could then be put in place while the 2776** user-entered SQL is being [sqlite3_prepare | prepared] that 2777** disallows everything except [SELECT] statements. 2778** 2779** Applications that need to process SQL from untrusted sources 2780** might also consider lowering resource limits using [sqlite3_limit()] 2781** and limiting database size using the [max_page_count] [PRAGMA] 2782** in addition to using an authorizer. 2783** 2784** ^(Only a single authorizer can be in place on a database connection 2785** at a time. Each call to sqlite3_set_authorizer overrides the 2786** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2787** The authorizer is disabled by default. 2788** 2789** The authorizer callback must not do anything that will modify 2790** the database connection that invoked the authorizer callback. 2791** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2792** database connections for the meaning of "modify" in this paragraph. 2793** 2794** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2795** statement might be re-prepared during [sqlite3_step()] due to a 2796** schema change. Hence, the application should ensure that the 2797** correct authorizer callback remains in place during the [sqlite3_step()]. 2798** 2799** ^Note that the authorizer callback is invoked only during 2800** [sqlite3_prepare()] or its variants. Authorization is not 2801** performed during statement evaluation in [sqlite3_step()], unless 2802** as stated in the previous paragraph, sqlite3_step() invokes 2803** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2804*/ 2805int sqlite3_set_authorizer( 2806 sqlite3*, 2807 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2808 void *pUserData 2809); 2810 2811/* 2812** CAPI3REF: Authorizer Return Codes 2813** 2814** The [sqlite3_set_authorizer | authorizer callback function] must 2815** return either [SQLITE_OK] or one of these two constants in order 2816** to signal SQLite whether or not the action is permitted. See the 2817** [sqlite3_set_authorizer | authorizer documentation] for additional 2818** information. 2819** 2820** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2821** returned from the [sqlite3_vtab_on_conflict()] interface. 2822*/ 2823#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2824#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2825 2826/* 2827** CAPI3REF: Authorizer Action Codes 2828** 2829** The [sqlite3_set_authorizer()] interface registers a callback function 2830** that is invoked to authorize certain SQL statement actions. The 2831** second parameter to the callback is an integer code that specifies 2832** what action is being authorized. These are the integer action codes that 2833** the authorizer callback may be passed. 2834** 2835** These action code values signify what kind of operation is to be 2836** authorized. The 3rd and 4th parameters to the authorization 2837** callback function will be parameters or NULL depending on which of these 2838** codes is used as the second parameter. ^(The 5th parameter to the 2839** authorizer callback is the name of the database ("main", "temp", 2840** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2841** is the name of the inner-most trigger or view that is responsible for 2842** the access attempt or NULL if this access attempt is directly from 2843** top-level SQL code. 2844*/ 2845/******************************************* 3rd ************ 4th ***********/ 2846#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2847#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2848#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2849#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2850#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2851#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2852#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2853#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2854#define SQLITE_DELETE 9 /* Table Name NULL */ 2855#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2856#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2857#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2858#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2859#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2860#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2861#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2862#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2863#define SQLITE_INSERT 18 /* Table Name NULL */ 2864#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2865#define SQLITE_READ 20 /* Table Name Column Name */ 2866#define SQLITE_SELECT 21 /* NULL NULL */ 2867#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2868#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2869#define SQLITE_ATTACH 24 /* Filename NULL */ 2870#define SQLITE_DETACH 25 /* Database Name NULL */ 2871#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2872#define SQLITE_REINDEX 27 /* Index Name NULL */ 2873#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2874#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2875#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2876#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2877#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2878#define SQLITE_COPY 0 /* No longer used */ 2879#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2880 2881/* 2882** CAPI3REF: Tracing And Profiling Functions 2883** METHOD: sqlite3 2884** 2885** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2886** instead of the routines described here. 2887** 2888** These routines register callback functions that can be used for 2889** tracing and profiling the execution of SQL statements. 2890** 2891** ^The callback function registered by sqlite3_trace() is invoked at 2892** various times when an SQL statement is being run by [sqlite3_step()]. 2893** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2894** SQL statement text as the statement first begins executing. 2895** ^(Additional sqlite3_trace() callbacks might occur 2896** as each triggered subprogram is entered. The callbacks for triggers 2897** contain a UTF-8 SQL comment that identifies the trigger.)^ 2898** 2899** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2900** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2901** 2902** ^The callback function registered by sqlite3_profile() is invoked 2903** as each SQL statement finishes. ^The profile callback contains 2904** the original statement text and an estimate of wall-clock time 2905** of how long that statement took to run. ^The profile callback 2906** time is in units of nanoseconds, however the current implementation 2907** is only capable of millisecond resolution so the six least significant 2908** digits in the time are meaningless. Future versions of SQLite 2909** might provide greater resolution on the profiler callback. The 2910** sqlite3_profile() function is considered experimental and is 2911** subject to change in future versions of SQLite. 2912*/ 2913SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2914 void(*xTrace)(void*,const char*), void*); 2915SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2916 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2917 2918/* 2919** CAPI3REF: SQL Trace Event Codes 2920** KEYWORDS: SQLITE_TRACE 2921** 2922** These constants identify classes of events that can be monitored 2923** using the [sqlite3_trace_v2()] tracing logic. The M argument 2924** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 2925** the following constants. ^The first argument to the trace callback 2926** is one of the following constants. 2927** 2928** New tracing constants may be added in future releases. 2929** 2930** ^A trace callback has four arguments: xCallback(T,C,P,X). 2931** ^The T argument is one of the integer type codes above. 2932** ^The C argument is a copy of the context pointer passed in as the 2933** fourth argument to [sqlite3_trace_v2()]. 2934** The P and X arguments are pointers whose meanings depend on T. 2935** 2936** <dl> 2937** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2938** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2939** first begins running and possibly at other times during the 2940** execution of the prepared statement, such as at the start of each 2941** trigger subprogram. ^The P argument is a pointer to the 2942** [prepared statement]. ^The X argument is a pointer to a string which 2943** is the unexpanded SQL text of the prepared statement or an SQL comment 2944** that indicates the invocation of a trigger. ^The callback can compute 2945** the same text that would have been returned by the legacy [sqlite3_trace()] 2946** interface by using the X argument when X begins with "--" and invoking 2947** [sqlite3_expanded_sql(P)] otherwise. 2948** 2949** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2950** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2951** information as is provided by the [sqlite3_profile()] callback. 2952** ^The P argument is a pointer to the [prepared statement] and the 2953** X argument points to a 64-bit integer which is the estimated of 2954** the number of nanosecond that the prepared statement took to run. 2955** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2956** 2957** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2958** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2959** statement generates a single row of result. 2960** ^The P argument is a pointer to the [prepared statement] and the 2961** X argument is unused. 2962** 2963** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2964** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2965** connection closes. 2966** ^The P argument is a pointer to the [database connection] object 2967** and the X argument is unused. 2968** </dl> 2969*/ 2970#define SQLITE_TRACE_STMT 0x01 2971#define SQLITE_TRACE_PROFILE 0x02 2972#define SQLITE_TRACE_ROW 0x04 2973#define SQLITE_TRACE_CLOSE 0x08 2974 2975/* 2976** CAPI3REF: SQL Trace Hook 2977** METHOD: sqlite3 2978** 2979** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2980** function X against [database connection] D, using property mask M 2981** and context pointer P. ^If the X callback is 2982** NULL or if the M mask is zero, then tracing is disabled. The 2983** M argument should be the bitwise OR-ed combination of 2984** zero or more [SQLITE_TRACE] constants. 2985** 2986** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2987** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2988** 2989** ^The X callback is invoked whenever any of the events identified by 2990** mask M occur. ^The integer return value from the callback is currently 2991** ignored, though this may change in future releases. Callback 2992** implementations should return zero to ensure future compatibility. 2993** 2994** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2995** ^The T argument is one of the [SQLITE_TRACE] 2996** constants to indicate why the callback was invoked. 2997** ^The C argument is a copy of the context pointer. 2998** The P and X arguments are pointers whose meanings depend on T. 2999** 3000** The sqlite3_trace_v2() interface is intended to replace the legacy 3001** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3002** are deprecated. 3003*/ 3004int sqlite3_trace_v2( 3005 sqlite3*, 3006 unsigned uMask, 3007 int(*xCallback)(unsigned,void*,void*,void*), 3008 void *pCtx 3009); 3010 3011/* 3012** CAPI3REF: Query Progress Callbacks 3013** METHOD: sqlite3 3014** 3015** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3016** function X to be invoked periodically during long running calls to 3017** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3018** database connection D. An example use for this 3019** interface is to keep a GUI updated during a large query. 3020** 3021** ^The parameter P is passed through as the only parameter to the 3022** callback function X. ^The parameter N is the approximate number of 3023** [virtual machine instructions] that are evaluated between successive 3024** invocations of the callback X. ^If N is less than one then the progress 3025** handler is disabled. 3026** 3027** ^Only a single progress handler may be defined at one time per 3028** [database connection]; setting a new progress handler cancels the 3029** old one. ^Setting parameter X to NULL disables the progress handler. 3030** ^The progress handler is also disabled by setting N to a value less 3031** than 1. 3032** 3033** ^If the progress callback returns non-zero, the operation is 3034** interrupted. This feature can be used to implement a 3035** "Cancel" button on a GUI progress dialog box. 3036** 3037** The progress handler callback must not do anything that will modify 3038** the database connection that invoked the progress handler. 3039** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3040** database connections for the meaning of "modify" in this paragraph. 3041** 3042*/ 3043void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3044 3045/* 3046** CAPI3REF: Opening A New Database Connection 3047** CONSTRUCTOR: sqlite3 3048** 3049** ^These routines open an SQLite database file as specified by the 3050** filename argument. ^The filename argument is interpreted as UTF-8 for 3051** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3052** order for sqlite3_open16(). ^(A [database connection] handle is usually 3053** returned in *ppDb, even if an error occurs. The only exception is that 3054** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3055** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3056** object.)^ ^(If the database is opened (and/or created) successfully, then 3057** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3058** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3059** an English language description of the error following a failure of any 3060** of the sqlite3_open() routines. 3061** 3062** ^The default encoding will be UTF-8 for databases created using 3063** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3064** created using sqlite3_open16() will be UTF-16 in the native byte order. 3065** 3066** Whether or not an error occurs when it is opened, resources 3067** associated with the [database connection] handle should be released by 3068** passing it to [sqlite3_close()] when it is no longer required. 3069** 3070** The sqlite3_open_v2() interface works like sqlite3_open() 3071** except that it accepts two additional parameters for additional control 3072** over the new database connection. ^(The flags parameter to 3073** sqlite3_open_v2() can take one of 3074** the following three values, optionally combined with the 3075** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3076** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3077** 3078** <dl> 3079** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3080** <dd>The database is opened in read-only mode. If the database does not 3081** already exist, an error is returned.</dd>)^ 3082** 3083** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3084** <dd>The database is opened for reading and writing if possible, or reading 3085** only if the file is write protected by the operating system. In either 3086** case the database must already exist, otherwise an error is returned.</dd>)^ 3087** 3088** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3089** <dd>The database is opened for reading and writing, and is created if 3090** it does not already exist. This is the behavior that is always used for 3091** sqlite3_open() and sqlite3_open16().</dd>)^ 3092** </dl> 3093** 3094** If the 3rd parameter to sqlite3_open_v2() is not one of the 3095** combinations shown above optionally combined with other 3096** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3097** then the behavior is undefined. 3098** 3099** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3100** opens in the multi-thread [threading mode] as long as the single-thread 3101** mode has not been set at compile-time or start-time. ^If the 3102** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3103** in the serialized [threading mode] unless single-thread was 3104** previously selected at compile-time or start-time. 3105** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3106** eligible to use [shared cache mode], regardless of whether or not shared 3107** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3108** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3109** participate in [shared cache mode] even if it is enabled. 3110** 3111** ^The fourth parameter to sqlite3_open_v2() is the name of the 3112** [sqlite3_vfs] object that defines the operating system interface that 3113** the new database connection should use. ^If the fourth parameter is 3114** a NULL pointer then the default [sqlite3_vfs] object is used. 3115** 3116** ^If the filename is ":memory:", then a private, temporary in-memory database 3117** is created for the connection. ^This in-memory database will vanish when 3118** the database connection is closed. Future versions of SQLite might 3119** make use of additional special filenames that begin with the ":" character. 3120** It is recommended that when a database filename actually does begin with 3121** a ":" character you should prefix the filename with a pathname such as 3122** "./" to avoid ambiguity. 3123** 3124** ^If the filename is an empty string, then a private, temporary 3125** on-disk database will be created. ^This private database will be 3126** automatically deleted as soon as the database connection is closed. 3127** 3128** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3129** 3130** ^If [URI filename] interpretation is enabled, and the filename argument 3131** begins with "file:", then the filename is interpreted as a URI. ^URI 3132** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3133** set in the third argument to sqlite3_open_v2(), or if it has 3134** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3135** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3136** URI filename interpretation is turned off 3137** by default, but future releases of SQLite might enable URI filename 3138** interpretation by default. See "[URI filenames]" for additional 3139** information. 3140** 3141** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3142** authority, then it must be either an empty string or the string 3143** "localhost". ^If the authority is not an empty string or "localhost", an 3144** error is returned to the caller. ^The fragment component of a URI, if 3145** present, is ignored. 3146** 3147** ^SQLite uses the path component of the URI as the name of the disk file 3148** which contains the database. ^If the path begins with a '/' character, 3149** then it is interpreted as an absolute path. ^If the path does not begin 3150** with a '/' (meaning that the authority section is omitted from the URI) 3151** then the path is interpreted as a relative path. 3152** ^(On windows, the first component of an absolute path 3153** is a drive specification (e.g. "C:").)^ 3154** 3155** [[core URI query parameters]] 3156** The query component of a URI may contain parameters that are interpreted 3157** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3158** SQLite and its built-in [VFSes] interpret the 3159** following query parameters: 3160** 3161** <ul> 3162** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3163** a VFS object that provides the operating system interface that should 3164** be used to access the database file on disk. ^If this option is set to 3165** an empty string the default VFS object is used. ^Specifying an unknown 3166** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3167** present, then the VFS specified by the option takes precedence over 3168** the value passed as the fourth parameter to sqlite3_open_v2(). 3169** 3170** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3171** "rwc", or "memory". Attempting to set it to any other value is 3172** an error)^. 3173** ^If "ro" is specified, then the database is opened for read-only 3174** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3175** third argument to sqlite3_open_v2(). ^If the mode option is set to 3176** "rw", then the database is opened for read-write (but not create) 3177** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3178** been set. ^Value "rwc" is equivalent to setting both 3179** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3180** set to "memory" then a pure [in-memory database] that never reads 3181** or writes from disk is used. ^It is an error to specify a value for 3182** the mode parameter that is less restrictive than that specified by 3183** the flags passed in the third parameter to sqlite3_open_v2(). 3184** 3185** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3186** "private". ^Setting it to "shared" is equivalent to setting the 3187** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3188** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3189** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3190** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3191** a URI filename, its value overrides any behavior requested by setting 3192** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3193** 3194** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3195** [powersafe overwrite] property does or does not apply to the 3196** storage media on which the database file resides. 3197** 3198** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3199** which if set disables file locking in rollback journal modes. This 3200** is useful for accessing a database on a filesystem that does not 3201** support locking. Caution: Database corruption might result if two 3202** or more processes write to the same database and any one of those 3203** processes uses nolock=1. 3204** 3205** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3206** parameter that indicates that the database file is stored on 3207** read-only media. ^When immutable is set, SQLite assumes that the 3208** database file cannot be changed, even by a process with higher 3209** privilege, and so the database is opened read-only and all locking 3210** and change detection is disabled. Caution: Setting the immutable 3211** property on a database file that does in fact change can result 3212** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3213** See also: [SQLITE_IOCAP_IMMUTABLE]. 3214** 3215** </ul> 3216** 3217** ^Specifying an unknown parameter in the query component of a URI is not an 3218** error. Future versions of SQLite might understand additional query 3219** parameters. See "[query parameters with special meaning to SQLite]" for 3220** additional information. 3221** 3222** [[URI filename examples]] <h3>URI filename examples</h3> 3223** 3224** <table border="1" align=center cellpadding=5> 3225** <tr><th> URI filenames <th> Results 3226** <tr><td> file:data.db <td> 3227** Open the file "data.db" in the current directory. 3228** <tr><td> file:/home/fred/data.db<br> 3229** file:///home/fred/data.db <br> 3230** file://localhost/home/fred/data.db <br> <td> 3231** Open the database file "/home/fred/data.db". 3232** <tr><td> file://darkstar/home/fred/data.db <td> 3233** An error. "darkstar" is not a recognized authority. 3234** <tr><td style="white-space:nowrap"> 3235** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3236** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3237** C:. Note that the %20 escaping in this example is not strictly 3238** necessary - space characters can be used literally 3239** in URI filenames. 3240** <tr><td> file:data.db?mode=ro&cache=private <td> 3241** Open file "data.db" in the current directory for read-only access. 3242** Regardless of whether or not shared-cache mode is enabled by 3243** default, use a private cache. 3244** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3245** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3246** that uses dot-files in place of posix advisory locking. 3247** <tr><td> file:data.db?mode=readonly <td> 3248** An error. "readonly" is not a valid option for the "mode" parameter. 3249** </table> 3250** 3251** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3252** query components of a URI. A hexadecimal escape sequence consists of a 3253** percent sign - "%" - followed by exactly two hexadecimal digits 3254** specifying an octet value. ^Before the path or query components of a 3255** URI filename are interpreted, they are encoded using UTF-8 and all 3256** hexadecimal escape sequences replaced by a single byte containing the 3257** corresponding octet. If this process generates an invalid UTF-8 encoding, 3258** the results are undefined. 3259** 3260** <b>Note to Windows users:</b> The encoding used for the filename argument 3261** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3262** codepage is currently defined. Filenames containing international 3263** characters must be converted to UTF-8 prior to passing them into 3264** sqlite3_open() or sqlite3_open_v2(). 3265** 3266** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3267** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3268** features that require the use of temporary files may fail. 3269** 3270** See also: [sqlite3_temp_directory] 3271*/ 3272int sqlite3_open( 3273 const char *filename, /* Database filename (UTF-8) */ 3274 sqlite3 **ppDb /* OUT: SQLite db handle */ 3275); 3276int sqlite3_open16( 3277 const void *filename, /* Database filename (UTF-16) */ 3278 sqlite3 **ppDb /* OUT: SQLite db handle */ 3279); 3280int sqlite3_open_v2( 3281 const char *filename, /* Database filename (UTF-8) */ 3282 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3283 int flags, /* Flags */ 3284 const char *zVfs /* Name of VFS module to use */ 3285); 3286 3287/* 3288** CAPI3REF: Obtain Values For URI Parameters 3289** 3290** These are utility routines, useful to VFS implementations, that check 3291** to see if a database file was a URI that contained a specific query 3292** parameter, and if so obtains the value of that query parameter. 3293** 3294** If F is the database filename pointer passed into the xOpen() method of 3295** a VFS implementation when the flags parameter to xOpen() has one or 3296** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3297** P is the name of the query parameter, then 3298** sqlite3_uri_parameter(F,P) returns the value of the P 3299** parameter if it exists or a NULL pointer if P does not appear as a 3300** query parameter on F. If P is a query parameter of F 3301** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3302** a pointer to an empty string. 3303** 3304** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3305** parameter and returns true (1) or false (0) according to the value 3306** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3307** value of query parameter P is one of "yes", "true", or "on" in any 3308** case or if the value begins with a non-zero number. The 3309** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3310** query parameter P is one of "no", "false", or "off" in any case or 3311** if the value begins with a numeric zero. If P is not a query 3312** parameter on F or if the value of P is does not match any of the 3313** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3314** 3315** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3316** 64-bit signed integer and returns that integer, or D if P does not 3317** exist. If the value of P is something other than an integer, then 3318** zero is returned. 3319** 3320** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3321** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3322** is not a database file pathname pointer that SQLite passed into the xOpen 3323** VFS method, then the behavior of this routine is undefined and probably 3324** undesirable. 3325*/ 3326const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3327int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3328sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3329 3330 3331/* 3332** CAPI3REF: Error Codes And Messages 3333** METHOD: sqlite3 3334** 3335** ^If the most recent sqlite3_* API call associated with 3336** [database connection] D failed, then the sqlite3_errcode(D) interface 3337** returns the numeric [result code] or [extended result code] for that 3338** API call. 3339** If the most recent API call was successful, 3340** then the return value from sqlite3_errcode() is undefined. 3341** ^The sqlite3_extended_errcode() 3342** interface is the same except that it always returns the 3343** [extended result code] even when extended result codes are 3344** disabled. 3345** 3346** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3347** text that describes the error, as either UTF-8 or UTF-16 respectively. 3348** ^(Memory to hold the error message string is managed internally. 3349** The application does not need to worry about freeing the result. 3350** However, the error string might be overwritten or deallocated by 3351** subsequent calls to other SQLite interface functions.)^ 3352** 3353** ^The sqlite3_errstr() interface returns the English-language text 3354** that describes the [result code], as UTF-8. 3355** ^(Memory to hold the error message string is managed internally 3356** and must not be freed by the application)^. 3357** 3358** When the serialized [threading mode] is in use, it might be the 3359** case that a second error occurs on a separate thread in between 3360** the time of the first error and the call to these interfaces. 3361** When that happens, the second error will be reported since these 3362** interfaces always report the most recent result. To avoid 3363** this, each thread can obtain exclusive use of the [database connection] D 3364** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3365** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3366** all calls to the interfaces listed here are completed. 3367** 3368** If an interface fails with SQLITE_MISUSE, that means the interface 3369** was invoked incorrectly by the application. In that case, the 3370** error code and message may or may not be set. 3371*/ 3372int sqlite3_errcode(sqlite3 *db); 3373int sqlite3_extended_errcode(sqlite3 *db); 3374const char *sqlite3_errmsg(sqlite3*); 3375const void *sqlite3_errmsg16(sqlite3*); 3376const char *sqlite3_errstr(int); 3377 3378/* 3379** CAPI3REF: Prepared Statement Object 3380** KEYWORDS: {prepared statement} {prepared statements} 3381** 3382** An instance of this object represents a single SQL statement that 3383** has been compiled into binary form and is ready to be evaluated. 3384** 3385** Think of each SQL statement as a separate computer program. The 3386** original SQL text is source code. A prepared statement object 3387** is the compiled object code. All SQL must be converted into a 3388** prepared statement before it can be run. 3389** 3390** The life-cycle of a prepared statement object usually goes like this: 3391** 3392** <ol> 3393** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3394** <li> Bind values to [parameters] using the sqlite3_bind_*() 3395** interfaces. 3396** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3397** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3398** to step 2. Do this zero or more times. 3399** <li> Destroy the object using [sqlite3_finalize()]. 3400** </ol> 3401*/ 3402typedef struct sqlite3_stmt sqlite3_stmt; 3403 3404/* 3405** CAPI3REF: Run-time Limits 3406** METHOD: sqlite3 3407** 3408** ^(This interface allows the size of various constructs to be limited 3409** on a connection by connection basis. The first parameter is the 3410** [database connection] whose limit is to be set or queried. The 3411** second parameter is one of the [limit categories] that define a 3412** class of constructs to be size limited. The third parameter is the 3413** new limit for that construct.)^ 3414** 3415** ^If the new limit is a negative number, the limit is unchanged. 3416** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3417** [limits | hard upper bound] 3418** set at compile-time by a C preprocessor macro called 3419** [limits | SQLITE_MAX_<i>NAME</i>]. 3420** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3421** ^Attempts to increase a limit above its hard upper bound are 3422** silently truncated to the hard upper bound. 3423** 3424** ^Regardless of whether or not the limit was changed, the 3425** [sqlite3_limit()] interface returns the prior value of the limit. 3426** ^Hence, to find the current value of a limit without changing it, 3427** simply invoke this interface with the third parameter set to -1. 3428** 3429** Run-time limits are intended for use in applications that manage 3430** both their own internal database and also databases that are controlled 3431** by untrusted external sources. An example application might be a 3432** web browser that has its own databases for storing history and 3433** separate databases controlled by JavaScript applications downloaded 3434** off the Internet. The internal databases can be given the 3435** large, default limits. Databases managed by external sources can 3436** be given much smaller limits designed to prevent a denial of service 3437** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3438** interface to further control untrusted SQL. The size of the database 3439** created by an untrusted script can be contained using the 3440** [max_page_count] [PRAGMA]. 3441** 3442** New run-time limit categories may be added in future releases. 3443*/ 3444int sqlite3_limit(sqlite3*, int id, int newVal); 3445 3446/* 3447** CAPI3REF: Run-Time Limit Categories 3448** KEYWORDS: {limit category} {*limit categories} 3449** 3450** These constants define various performance limits 3451** that can be lowered at run-time using [sqlite3_limit()]. 3452** The synopsis of the meanings of the various limits is shown below. 3453** Additional information is available at [limits | Limits in SQLite]. 3454** 3455** <dl> 3456** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3457** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3458** 3459** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3460** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3461** 3462** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3463** <dd>The maximum number of columns in a table definition or in the 3464** result set of a [SELECT] or the maximum number of columns in an index 3465** or in an ORDER BY or GROUP BY clause.</dd>)^ 3466** 3467** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3468** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3469** 3470** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3471** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3472** 3473** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3474** <dd>The maximum number of instructions in a virtual machine program 3475** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3476** the equivalent tries to allocate space for more than this many opcodes 3477** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3478** 3479** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3480** <dd>The maximum number of arguments on a function.</dd>)^ 3481** 3482** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3483** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3484** 3485** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3486** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3487** <dd>The maximum length of the pattern argument to the [LIKE] or 3488** [GLOB] operators.</dd>)^ 3489** 3490** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3491** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3492** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3493** 3494** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3495** <dd>The maximum depth of recursion for triggers.</dd>)^ 3496** 3497** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3498** <dd>The maximum number of auxiliary worker threads that a single 3499** [prepared statement] may start.</dd>)^ 3500** </dl> 3501*/ 3502#define SQLITE_LIMIT_LENGTH 0 3503#define SQLITE_LIMIT_SQL_LENGTH 1 3504#define SQLITE_LIMIT_COLUMN 2 3505#define SQLITE_LIMIT_EXPR_DEPTH 3 3506#define SQLITE_LIMIT_COMPOUND_SELECT 4 3507#define SQLITE_LIMIT_VDBE_OP 5 3508#define SQLITE_LIMIT_FUNCTION_ARG 6 3509#define SQLITE_LIMIT_ATTACHED 7 3510#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3511#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3512#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3513#define SQLITE_LIMIT_WORKER_THREADS 11 3514 3515/* 3516** CAPI3REF: Prepare Flags 3517** 3518** These constants define various flags that can be passed into 3519** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3520** [sqlite3_prepare16_v3()] interfaces. 3521** 3522** New flags may be added in future releases of SQLite. 3523** 3524** <dl> 3525** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3526** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3527** that the prepared statement will be retained for a long time and 3528** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3529** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3530** be used just once or at most a few times and then destroyed using 3531** [sqlite3_finalize()] relatively soon. The current implementation acts 3532** on this hint by avoiding the use of [lookaside memory] so as not to 3533** deplete the limited store of lookaside memory. Future versions of 3534** SQLite may act on this hint differently. 3535** </dl> 3536*/ 3537#define SQLITE_PREPARE_PERSISTENT 0x01 3538 3539/* 3540** CAPI3REF: Compiling An SQL Statement 3541** KEYWORDS: {SQL statement compiler} 3542** METHOD: sqlite3 3543** CONSTRUCTOR: sqlite3_stmt 3544** 3545** To execute an SQL statement, it must first be compiled into a byte-code 3546** program using one of these routines. Or, in other words, these routines 3547** are constructors for the [prepared statement] object. 3548** 3549** The preferred routine to use is [sqlite3_prepare_v2()]. The 3550** [sqlite3_prepare()] interface is legacy and should be avoided. 3551** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3552** for special purposes. 3553** 3554** The use of the UTF-8 interfaces is preferred, as SQLite currently 3555** does all parsing using UTF-8. The UTF-16 interfaces are provided 3556** as a convenience. The UTF-16 interfaces work by converting the 3557** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3558** 3559** The first argument, "db", is a [database connection] obtained from a 3560** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3561** [sqlite3_open16()]. The database connection must not have been closed. 3562** 3563** The second argument, "zSql", is the statement to be compiled, encoded 3564** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3565** and sqlite3_prepare_v3() 3566** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3567** and sqlite3_prepare16_v3() use UTF-16. 3568** 3569** ^If the nByte argument is negative, then zSql is read up to the 3570** first zero terminator. ^If nByte is positive, then it is the 3571** number of bytes read from zSql. ^If nByte is zero, then no prepared 3572** statement is generated. 3573** If the caller knows that the supplied string is nul-terminated, then 3574** there is a small performance advantage to passing an nByte parameter that 3575** is the number of bytes in the input string <i>including</i> 3576** the nul-terminator. 3577** 3578** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3579** past the end of the first SQL statement in zSql. These routines only 3580** compile the first statement in zSql, so *pzTail is left pointing to 3581** what remains uncompiled. 3582** 3583** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3584** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3585** to NULL. ^If the input text contains no SQL (if the input is an empty 3586** string or a comment) then *ppStmt is set to NULL. 3587** The calling procedure is responsible for deleting the compiled 3588** SQL statement using [sqlite3_finalize()] after it has finished with it. 3589** ppStmt may not be NULL. 3590** 3591** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3592** otherwise an [error code] is returned. 3593** 3594** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3595** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3596** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3597** are retained for backwards compatibility, but their use is discouraged. 3598** ^In the "vX" interfaces, the prepared statement 3599** that is returned (the [sqlite3_stmt] object) contains a copy of the 3600** original SQL text. This causes the [sqlite3_step()] interface to 3601** behave differently in three ways: 3602** 3603** <ol> 3604** <li> 3605** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3606** always used to do, [sqlite3_step()] will automatically recompile the SQL 3607** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3608** retries will occur before sqlite3_step() gives up and returns an error. 3609** </li> 3610** 3611** <li> 3612** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3613** [error codes] or [extended error codes]. ^The legacy behavior was that 3614** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3615** and the application would have to make a second call to [sqlite3_reset()] 3616** in order to find the underlying cause of the problem. With the "v2" prepare 3617** interfaces, the underlying reason for the error is returned immediately. 3618** </li> 3619** 3620** <li> 3621** ^If the specific value bound to [parameter | host parameter] in the 3622** WHERE clause might influence the choice of query plan for a statement, 3623** then the statement will be automatically recompiled, as if there had been 3624** a schema change, on the first [sqlite3_step()] call following any change 3625** to the [sqlite3_bind_text | bindings] of that [parameter]. 3626** ^The specific value of WHERE-clause [parameter] might influence the 3627** choice of query plan if the parameter is the left-hand side of a [LIKE] 3628** or [GLOB] operator or if the parameter is compared to an indexed column 3629** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3630** </li> 3631** </ol> 3632** 3633** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3634** the extra prepFlags parameter, which is a bit array consisting of zero or 3635** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3636** sqlite3_prepare_v2() interface works exactly the same as 3637** sqlite3_prepare_v3() with a zero prepFlags parameter. 3638*/ 3639int sqlite3_prepare( 3640 sqlite3 *db, /* Database handle */ 3641 const char *zSql, /* SQL statement, UTF-8 encoded */ 3642 int nByte, /* Maximum length of zSql in bytes. */ 3643 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3644 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3645); 3646int sqlite3_prepare_v2( 3647 sqlite3 *db, /* Database handle */ 3648 const char *zSql, /* SQL statement, UTF-8 encoded */ 3649 int nByte, /* Maximum length of zSql in bytes. */ 3650 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3651 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3652); 3653int sqlite3_prepare_v3( 3654 sqlite3 *db, /* Database handle */ 3655 const char *zSql, /* SQL statement, UTF-8 encoded */ 3656 int nByte, /* Maximum length of zSql in bytes. */ 3657 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3658 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3659 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3660); 3661int sqlite3_prepare16( 3662 sqlite3 *db, /* Database handle */ 3663 const void *zSql, /* SQL statement, UTF-16 encoded */ 3664 int nByte, /* Maximum length of zSql in bytes. */ 3665 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3666 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3667); 3668int sqlite3_prepare16_v2( 3669 sqlite3 *db, /* Database handle */ 3670 const void *zSql, /* SQL statement, UTF-16 encoded */ 3671 int nByte, /* Maximum length of zSql in bytes. */ 3672 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3673 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3674); 3675int sqlite3_prepare16_v3( 3676 sqlite3 *db, /* Database handle */ 3677 const void *zSql, /* SQL statement, UTF-16 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 void **pzTail /* OUT: Pointer to unused portion of zSql */ 3682); 3683 3684/* 3685** CAPI3REF: Retrieving Statement SQL 3686** METHOD: sqlite3_stmt 3687** 3688** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3689** SQL text used to create [prepared statement] P if P was 3690** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3691** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3692** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3693** string containing the SQL text of prepared statement P with 3694** [bound parameters] expanded. 3695** 3696** ^(For example, if a prepared statement is created using the SQL 3697** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3698** and parameter :xyz is unbound, then sqlite3_sql() will return 3699** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3700** will return "SELECT 2345,NULL".)^ 3701** 3702** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3703** is available to hold the result, or if the result would exceed the 3704** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3705** 3706** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3707** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3708** option causes sqlite3_expanded_sql() to always return NULL. 3709** 3710** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3711** automatically freed when the prepared statement is finalized. 3712** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3713** is obtained from [sqlite3_malloc()] and must be free by the application 3714** by passing it to [sqlite3_free()]. 3715*/ 3716const char *sqlite3_sql(sqlite3_stmt *pStmt); 3717char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3718 3719/* 3720** CAPI3REF: Determine If An SQL Statement Writes The Database 3721** METHOD: sqlite3_stmt 3722** 3723** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3724** and only if the [prepared statement] X makes no direct changes to 3725** the content of the database file. 3726** 3727** Note that [application-defined SQL functions] or 3728** [virtual tables] might change the database indirectly as a side effect. 3729** ^(For example, if an application defines a function "eval()" that 3730** calls [sqlite3_exec()], then the following SQL statement would 3731** change the database file through side-effects: 3732** 3733** <blockquote><pre> 3734** SELECT eval('DELETE FROM t1') FROM t2; 3735** </pre></blockquote> 3736** 3737** But because the [SELECT] statement does not change the database file 3738** directly, sqlite3_stmt_readonly() would still return true.)^ 3739** 3740** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3741** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3742** since the statements themselves do not actually modify the database but 3743** rather they control the timing of when other statements modify the 3744** database. ^The [ATTACH] and [DETACH] statements also cause 3745** sqlite3_stmt_readonly() to return true since, while those statements 3746** change the configuration of a database connection, they do not make 3747** changes to the content of the database files on disk. 3748** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3749** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3750** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3751** sqlite3_stmt_readonly() returns false for those commands. 3752*/ 3753int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3754 3755/* 3756** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3757** METHOD: sqlite3_stmt 3758** 3759** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3760** [prepared statement] S has been stepped at least once using 3761** [sqlite3_step(S)] but has neither run to completion (returned 3762** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3763** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3764** interface returns false if S is a NULL pointer. If S is not a 3765** NULL pointer and is not a pointer to a valid [prepared statement] 3766** object, then the behavior is undefined and probably undesirable. 3767** 3768** This interface can be used in combination [sqlite3_next_stmt()] 3769** to locate all prepared statements associated with a database 3770** connection that are in need of being reset. This can be used, 3771** for example, in diagnostic routines to search for prepared 3772** statements that are holding a transaction open. 3773*/ 3774int sqlite3_stmt_busy(sqlite3_stmt*); 3775 3776/* 3777** CAPI3REF: Dynamically Typed Value Object 3778** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3779** 3780** SQLite uses the sqlite3_value object to represent all values 3781** that can be stored in a database table. SQLite uses dynamic typing 3782** for the values it stores. ^Values stored in sqlite3_value objects 3783** can be integers, floating point values, strings, BLOBs, or NULL. 3784** 3785** An sqlite3_value object may be either "protected" or "unprotected". 3786** Some interfaces require a protected sqlite3_value. Other interfaces 3787** will accept either a protected or an unprotected sqlite3_value. 3788** Every interface that accepts sqlite3_value arguments specifies 3789** whether or not it requires a protected sqlite3_value. The 3790** [sqlite3_value_dup()] interface can be used to construct a new 3791** protected sqlite3_value from an unprotected sqlite3_value. 3792** 3793** The terms "protected" and "unprotected" refer to whether or not 3794** a mutex is held. An internal mutex is held for a protected 3795** sqlite3_value object but no mutex is held for an unprotected 3796** sqlite3_value object. If SQLite is compiled to be single-threaded 3797** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3798** or if SQLite is run in one of reduced mutex modes 3799** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3800** then there is no distinction between protected and unprotected 3801** sqlite3_value objects and they can be used interchangeably. However, 3802** for maximum code portability it is recommended that applications 3803** still make the distinction between protected and unprotected 3804** sqlite3_value objects even when not strictly required. 3805** 3806** ^The sqlite3_value objects that are passed as parameters into the 3807** implementation of [application-defined SQL functions] are protected. 3808** ^The sqlite3_value object returned by 3809** [sqlite3_column_value()] is unprotected. 3810** Unprotected sqlite3_value objects may only be used as arguments 3811** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3812** [sqlite3_value_dup()]. 3813** The [sqlite3_value_blob | sqlite3_value_type()] family of 3814** interfaces require protected sqlite3_value objects. 3815*/ 3816typedef struct sqlite3_value sqlite3_value; 3817 3818/* 3819** CAPI3REF: SQL Function Context Object 3820** 3821** The context in which an SQL function executes is stored in an 3822** sqlite3_context object. ^A pointer to an sqlite3_context object 3823** is always first parameter to [application-defined SQL functions]. 3824** The application-defined SQL function implementation will pass this 3825** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3826** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3827** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3828** and/or [sqlite3_set_auxdata()]. 3829*/ 3830typedef struct sqlite3_context sqlite3_context; 3831 3832/* 3833** CAPI3REF: Binding Values To Prepared Statements 3834** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3835** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3836** METHOD: sqlite3_stmt 3837** 3838** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3839** literals may be replaced by a [parameter] that matches one of following 3840** templates: 3841** 3842** <ul> 3843** <li> ? 3844** <li> ?NNN 3845** <li> :VVV 3846** <li> @VVV 3847** <li> $VVV 3848** </ul> 3849** 3850** In the templates above, NNN represents an integer literal, 3851** and VVV represents an alphanumeric identifier.)^ ^The values of these 3852** parameters (also called "host parameter names" or "SQL parameters") 3853** can be set using the sqlite3_bind_*() routines defined here. 3854** 3855** ^The first argument to the sqlite3_bind_*() routines is always 3856** a pointer to the [sqlite3_stmt] object returned from 3857** [sqlite3_prepare_v2()] or its variants. 3858** 3859** ^The second argument is the index of the SQL parameter to be set. 3860** ^The leftmost SQL parameter has an index of 1. ^When the same named 3861** SQL parameter is used more than once, second and subsequent 3862** occurrences have the same index as the first occurrence. 3863** ^The index for named parameters can be looked up using the 3864** [sqlite3_bind_parameter_index()] API if desired. ^The index 3865** for "?NNN" parameters is the value of NNN. 3866** ^The NNN value must be between 1 and the [sqlite3_limit()] 3867** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3868** 3869** ^The third argument is the value to bind to the parameter. 3870** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3871** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3872** is ignored and the end result is the same as sqlite3_bind_null(). 3873** 3874** ^(In those routines that have a fourth argument, its value is the 3875** number of bytes in the parameter. To be clear: the value is the 3876** number of <u>bytes</u> in the value, not the number of characters.)^ 3877** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3878** is negative, then the length of the string is 3879** the number of bytes up to the first zero terminator. 3880** If the fourth parameter to sqlite3_bind_blob() is negative, then 3881** the behavior is undefined. 3882** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3883** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3884** that parameter must be the byte offset 3885** where the NUL terminator would occur assuming the string were NUL 3886** terminated. If any NUL characters occur at byte offsets less than 3887** the value of the fourth parameter then the resulting string value will 3888** contain embedded NULs. The result of expressions involving strings 3889** with embedded NULs is undefined. 3890** 3891** ^The fifth argument to the BLOB and string binding interfaces 3892** is a destructor used to dispose of the BLOB or 3893** string after SQLite has finished with it. ^The destructor is called 3894** to dispose of the BLOB or string even if the call to bind API fails. 3895** ^If the fifth argument is 3896** the special value [SQLITE_STATIC], then SQLite assumes that the 3897** information is in static, unmanaged space and does not need to be freed. 3898** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3899** SQLite makes its own private copy of the data immediately, before 3900** the sqlite3_bind_*() routine returns. 3901** 3902** ^The sixth argument to sqlite3_bind_text64() must be one of 3903** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3904** to specify the encoding of the text in the third parameter. If 3905** the sixth argument to sqlite3_bind_text64() is not one of the 3906** allowed values shown above, or if the text encoding is different 3907** from the encoding specified by the sixth parameter, then the behavior 3908** is undefined. 3909** 3910** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3911** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3912** (just an integer to hold its size) while it is being processed. 3913** Zeroblobs are intended to serve as placeholders for BLOBs whose 3914** content is later written using 3915** [sqlite3_blob_open | incremental BLOB I/O] routines. 3916** ^A negative value for the zeroblob results in a zero-length BLOB. 3917** 3918** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3919** [prepared statement] S to have an SQL value of NULL, but to also be 3920** associated with the pointer P of type T. ^D is either a NULL pointer or 3921** a pointer to a destructor function for P. ^SQLite will invoke the 3922** destructor D with a single argument of P when it is finished using 3923** P. The T parameter should be a static string, preferably a string 3924** literal. The sqlite3_bind_pointer() routine is part of the 3925** [pointer passing interface] added for SQLite 3.20.0. 3926** 3927** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3928** for the [prepared statement] or with a prepared statement for which 3929** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3930** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3931** routine is passed a [prepared statement] that has been finalized, the 3932** result is undefined and probably harmful. 3933** 3934** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3935** ^Unbound parameters are interpreted as NULL. 3936** 3937** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3938** [error code] if anything goes wrong. 3939** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3940** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3941** [SQLITE_MAX_LENGTH]. 3942** ^[SQLITE_RANGE] is returned if the parameter 3943** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3944** 3945** See also: [sqlite3_bind_parameter_count()], 3946** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3947*/ 3948int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3949int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3950 void(*)(void*)); 3951int sqlite3_bind_double(sqlite3_stmt*, int, double); 3952int sqlite3_bind_int(sqlite3_stmt*, int, int); 3953int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3954int sqlite3_bind_null(sqlite3_stmt*, int); 3955int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3956int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3957int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3958 void(*)(void*), unsigned char encoding); 3959int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3960int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3961int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3962int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3963 3964/* 3965** CAPI3REF: Number Of SQL Parameters 3966** METHOD: sqlite3_stmt 3967** 3968** ^This routine can be used to find the number of [SQL parameters] 3969** in a [prepared statement]. SQL parameters are tokens of the 3970** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3971** placeholders for values that are [sqlite3_bind_blob | bound] 3972** to the parameters at a later time. 3973** 3974** ^(This routine actually returns the index of the largest (rightmost) 3975** parameter. For all forms except ?NNN, this will correspond to the 3976** number of unique parameters. If parameters of the ?NNN form are used, 3977** there may be gaps in the list.)^ 3978** 3979** See also: [sqlite3_bind_blob|sqlite3_bind()], 3980** [sqlite3_bind_parameter_name()], and 3981** [sqlite3_bind_parameter_index()]. 3982*/ 3983int sqlite3_bind_parameter_count(sqlite3_stmt*); 3984 3985/* 3986** CAPI3REF: Name Of A Host Parameter 3987** METHOD: sqlite3_stmt 3988** 3989** ^The sqlite3_bind_parameter_name(P,N) interface returns 3990** the name of the N-th [SQL parameter] in the [prepared statement] P. 3991** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3992** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3993** respectively. 3994** In other words, the initial ":" or "$" or "@" or "?" 3995** is included as part of the name.)^ 3996** ^Parameters of the form "?" without a following integer have no name 3997** and are referred to as "nameless" or "anonymous parameters". 3998** 3999** ^The first host parameter has an index of 1, not 0. 4000** 4001** ^If the value N is out of range or if the N-th parameter is 4002** nameless, then NULL is returned. ^The returned string is 4003** always in UTF-8 encoding even if the named parameter was 4004** originally specified as UTF-16 in [sqlite3_prepare16()], 4005** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4006** 4007** See also: [sqlite3_bind_blob|sqlite3_bind()], 4008** [sqlite3_bind_parameter_count()], and 4009** [sqlite3_bind_parameter_index()]. 4010*/ 4011const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4012 4013/* 4014** CAPI3REF: Index Of A Parameter With A Given Name 4015** METHOD: sqlite3_stmt 4016** 4017** ^Return the index of an SQL parameter given its name. ^The 4018** index value returned is suitable for use as the second 4019** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4020** is returned if no matching parameter is found. ^The parameter 4021** name must be given in UTF-8 even if the original statement 4022** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4023** [sqlite3_prepare16_v3()]. 4024** 4025** See also: [sqlite3_bind_blob|sqlite3_bind()], 4026** [sqlite3_bind_parameter_count()], and 4027** [sqlite3_bind_parameter_name()]. 4028*/ 4029int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4030 4031/* 4032** CAPI3REF: Reset All Bindings On A Prepared Statement 4033** METHOD: sqlite3_stmt 4034** 4035** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4036** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4037** ^Use this routine to reset all host parameters to NULL. 4038*/ 4039int sqlite3_clear_bindings(sqlite3_stmt*); 4040 4041/* 4042** CAPI3REF: Number Of Columns In A Result Set 4043** METHOD: sqlite3_stmt 4044** 4045** ^Return the number of columns in the result set returned by the 4046** [prepared statement]. ^If this routine returns 0, that means the 4047** [prepared statement] returns no data (for example an [UPDATE]). 4048** ^However, just because this routine returns a positive number does not 4049** mean that one or more rows of data will be returned. ^A SELECT statement 4050** will always have a positive sqlite3_column_count() but depending on the 4051** WHERE clause constraints and the table content, it might return no rows. 4052** 4053** See also: [sqlite3_data_count()] 4054*/ 4055int sqlite3_column_count(sqlite3_stmt *pStmt); 4056 4057/* 4058** CAPI3REF: Column Names In A Result Set 4059** METHOD: sqlite3_stmt 4060** 4061** ^These routines return the name assigned to a particular column 4062** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4063** interface returns a pointer to a zero-terminated UTF-8 string 4064** and sqlite3_column_name16() returns a pointer to a zero-terminated 4065** UTF-16 string. ^The first parameter is the [prepared statement] 4066** that implements the [SELECT] statement. ^The second parameter is the 4067** column number. ^The leftmost column is number 0. 4068** 4069** ^The returned string pointer is valid until either the [prepared statement] 4070** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4071** reprepared by the first call to [sqlite3_step()] for a particular run 4072** or until the next call to 4073** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4074** 4075** ^If sqlite3_malloc() fails during the processing of either routine 4076** (for example during a conversion from UTF-8 to UTF-16) then a 4077** NULL pointer is returned. 4078** 4079** ^The name of a result column is the value of the "AS" clause for 4080** that column, if there is an AS clause. If there is no AS clause 4081** then the name of the column is unspecified and may change from 4082** one release of SQLite to the next. 4083*/ 4084const char *sqlite3_column_name(sqlite3_stmt*, int N); 4085const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4086 4087/* 4088** CAPI3REF: Source Of Data In A Query Result 4089** METHOD: sqlite3_stmt 4090** 4091** ^These routines provide a means to determine the database, table, and 4092** table column that is the origin of a particular result column in 4093** [SELECT] statement. 4094** ^The name of the database or table or column can be returned as 4095** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4096** the database name, the _table_ routines return the table name, and 4097** the origin_ routines return the column name. 4098** ^The returned string is valid until the [prepared statement] is destroyed 4099** using [sqlite3_finalize()] or until the statement is automatically 4100** reprepared by the first call to [sqlite3_step()] for a particular run 4101** or until the same information is requested 4102** again in a different encoding. 4103** 4104** ^The names returned are the original un-aliased names of the 4105** database, table, and column. 4106** 4107** ^The first argument to these interfaces is a [prepared statement]. 4108** ^These functions return information about the Nth result column returned by 4109** the statement, where N is the second function argument. 4110** ^The left-most column is column 0 for these routines. 4111** 4112** ^If the Nth column returned by the statement is an expression or 4113** subquery and is not a column value, then all of these functions return 4114** NULL. ^These routine might also return NULL if a memory allocation error 4115** occurs. ^Otherwise, they return the name of the attached database, table, 4116** or column that query result column was extracted from. 4117** 4118** ^As with all other SQLite APIs, those whose names end with "16" return 4119** UTF-16 encoded strings and the other functions return UTF-8. 4120** 4121** ^These APIs are only available if the library was compiled with the 4122** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4123** 4124** If two or more threads call one or more of these routines against the same 4125** prepared statement and column at the same time then the results are 4126** undefined. 4127** 4128** If two or more threads call one or more 4129** [sqlite3_column_database_name | column metadata interfaces] 4130** for the same [prepared statement] and result column 4131** at the same time then the results are undefined. 4132*/ 4133const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4134const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4135const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4136const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4137const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4138const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4139 4140/* 4141** CAPI3REF: Declared Datatype Of A Query Result 4142** METHOD: sqlite3_stmt 4143** 4144** ^(The first parameter is a [prepared statement]. 4145** If this statement is a [SELECT] statement and the Nth column of the 4146** returned result set of that [SELECT] is a table column (not an 4147** expression or subquery) then the declared type of the table 4148** column is returned.)^ ^If the Nth column of the result set is an 4149** expression or subquery, then a NULL pointer is returned. 4150** ^The returned string is always UTF-8 encoded. 4151** 4152** ^(For example, given the database schema: 4153** 4154** CREATE TABLE t1(c1 VARIANT); 4155** 4156** and the following statement to be compiled: 4157** 4158** SELECT c1 + 1, c1 FROM t1; 4159** 4160** this routine would return the string "VARIANT" for the second result 4161** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4162** 4163** ^SQLite uses dynamic run-time typing. ^So just because a column 4164** is declared to contain a particular type does not mean that the 4165** data stored in that column is of the declared type. SQLite is 4166** strongly typed, but the typing is dynamic not static. ^Type 4167** is associated with individual values, not with the containers 4168** used to hold those values. 4169*/ 4170const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4171const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4172 4173/* 4174** CAPI3REF: Evaluate An SQL Statement 4175** METHOD: sqlite3_stmt 4176** 4177** After a [prepared statement] has been prepared using any of 4178** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4179** or [sqlite3_prepare16_v3()] or one of the legacy 4180** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4181** must be called one or more times to evaluate the statement. 4182** 4183** The details of the behavior of the sqlite3_step() interface depend 4184** on whether the statement was prepared using the newer "vX" interfaces 4185** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4186** [sqlite3_prepare16_v2()] or the older legacy 4187** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4188** new "vX" interface is recommended for new applications but the legacy 4189** interface will continue to be supported. 4190** 4191** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4192** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4193** ^With the "v2" interface, any of the other [result codes] or 4194** [extended result codes] might be returned as well. 4195** 4196** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4197** database locks it needs to do its job. ^If the statement is a [COMMIT] 4198** or occurs outside of an explicit transaction, then you can retry the 4199** statement. If the statement is not a [COMMIT] and occurs within an 4200** explicit transaction then you should rollback the transaction before 4201** continuing. 4202** 4203** ^[SQLITE_DONE] means that the statement has finished executing 4204** successfully. sqlite3_step() should not be called again on this virtual 4205** machine without first calling [sqlite3_reset()] to reset the virtual 4206** machine back to its initial state. 4207** 4208** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4209** is returned each time a new row of data is ready for processing by the 4210** caller. The values may be accessed using the [column access functions]. 4211** sqlite3_step() is called again to retrieve the next row of data. 4212** 4213** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4214** violation) has occurred. sqlite3_step() should not be called again on 4215** the VM. More information may be found by calling [sqlite3_errmsg()]. 4216** ^With the legacy interface, a more specific error code (for example, 4217** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4218** can be obtained by calling [sqlite3_reset()] on the 4219** [prepared statement]. ^In the "v2" interface, 4220** the more specific error code is returned directly by sqlite3_step(). 4221** 4222** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4223** Perhaps it was called on a [prepared statement] that has 4224** already been [sqlite3_finalize | finalized] or on one that had 4225** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4226** be the case that the same database connection is being used by two or 4227** more threads at the same moment in time. 4228** 4229** For all versions of SQLite up to and including 3.6.23.1, a call to 4230** [sqlite3_reset()] was required after sqlite3_step() returned anything 4231** other than [SQLITE_ROW] before any subsequent invocation of 4232** sqlite3_step(). Failure to reset the prepared statement using 4233** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4234** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4235** sqlite3_step() began 4236** calling [sqlite3_reset()] automatically in this circumstance rather 4237** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4238** break because any application that ever receives an SQLITE_MISUSE error 4239** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4240** can be used to restore the legacy behavior. 4241** 4242** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4243** API always returns a generic error code, [SQLITE_ERROR], following any 4244** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4245** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4246** specific [error codes] that better describes the error. 4247** We admit that this is a goofy design. The problem has been fixed 4248** with the "v2" interface. If you prepare all of your SQL statements 4249** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4250** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4251** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4252** then the more specific [error codes] are returned directly 4253** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4254*/ 4255int sqlite3_step(sqlite3_stmt*); 4256 4257/* 4258** CAPI3REF: Number of columns in a result set 4259** METHOD: sqlite3_stmt 4260** 4261** ^The sqlite3_data_count(P) interface returns the number of columns in the 4262** current row of the result set of [prepared statement] P. 4263** ^If prepared statement P does not have results ready to return 4264** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4265** interfaces) then sqlite3_data_count(P) returns 0. 4266** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4267** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4268** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4269** will return non-zero if previous call to [sqlite3_step](P) returned 4270** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4271** where it always returns zero since each step of that multi-step 4272** pragma returns 0 columns of data. 4273** 4274** See also: [sqlite3_column_count()] 4275*/ 4276int sqlite3_data_count(sqlite3_stmt *pStmt); 4277 4278/* 4279** CAPI3REF: Fundamental Datatypes 4280** KEYWORDS: SQLITE_TEXT 4281** 4282** ^(Every value in SQLite has one of five fundamental datatypes: 4283** 4284** <ul> 4285** <li> 64-bit signed integer 4286** <li> 64-bit IEEE floating point number 4287** <li> string 4288** <li> BLOB 4289** <li> NULL 4290** </ul>)^ 4291** 4292** These constants are codes for each of those types. 4293** 4294** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4295** for a completely different meaning. Software that links against both 4296** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4297** SQLITE_TEXT. 4298*/ 4299#define SQLITE_INTEGER 1 4300#define SQLITE_FLOAT 2 4301#define SQLITE_BLOB 4 4302#define SQLITE_NULL 5 4303#ifdef SQLITE_TEXT 4304# undef SQLITE_TEXT 4305#else 4306# define SQLITE_TEXT 3 4307#endif 4308#define SQLITE3_TEXT 3 4309 4310/* 4311** CAPI3REF: Result Values From A Query 4312** KEYWORDS: {column access functions} 4313** METHOD: sqlite3_stmt 4314** 4315** <b>Summary:</b> 4316** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4317** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4318** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4319** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4320** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4321** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4322** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4323** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4324** [sqlite3_value|unprotected sqlite3_value] object. 4325** <tr><td> <td> <td> 4326** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4327** or a UTF-8 TEXT result in bytes 4328** <tr><td><b>sqlite3_column_bytes16 </b> 4329** <td>→ <td>Size of UTF-16 4330** TEXT in bytes 4331** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4332** datatype of the result 4333** </table></blockquote> 4334** 4335** <b>Details:</b> 4336** 4337** ^These routines return information about a single column of the current 4338** result row of a query. ^In every case the first argument is a pointer 4339** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4340** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4341** and the second argument is the index of the column for which information 4342** should be returned. ^The leftmost column of the result set has the index 0. 4343** ^The number of columns in the result can be determined using 4344** [sqlite3_column_count()]. 4345** 4346** If the SQL statement does not currently point to a valid row, or if the 4347** column index is out of range, the result is undefined. 4348** These routines may only be called when the most recent call to 4349** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4350** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4351** If any of these routines are called after [sqlite3_reset()] or 4352** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4353** something other than [SQLITE_ROW], the results are undefined. 4354** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4355** are called from a different thread while any of these routines 4356** are pending, then the results are undefined. 4357** 4358** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4359** each return the value of a result column in a specific data format. If 4360** the result column is not initially in the requested format (for example, 4361** if the query returns an integer but the sqlite3_column_text() interface 4362** is used to extract the value) then an automatic type conversion is performed. 4363** 4364** ^The sqlite3_column_type() routine returns the 4365** [SQLITE_INTEGER | datatype code] for the initial data type 4366** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4367** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4368** The return value of sqlite3_column_type() can be used to decide which 4369** of the first six interface should be used to extract the column value. 4370** The value returned by sqlite3_column_type() is only meaningful if no 4371** automatic type conversions have occurred for the value in question. 4372** After a type conversion, the result of calling sqlite3_column_type() 4373** is undefined, though harmless. Future 4374** versions of SQLite may change the behavior of sqlite3_column_type() 4375** following a type conversion. 4376** 4377** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4378** or sqlite3_column_bytes16() interfaces can be used to determine the size 4379** of that BLOB or string. 4380** 4381** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4382** routine returns the number of bytes in that BLOB or string. 4383** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4384** the string to UTF-8 and then returns the number of bytes. 4385** ^If the result is a numeric value then sqlite3_column_bytes() uses 4386** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4387** the number of bytes in that string. 4388** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4389** 4390** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4391** routine returns the number of bytes in that BLOB or string. 4392** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4393** the string to UTF-16 and then returns the number of bytes. 4394** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4395** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4396** the number of bytes in that string. 4397** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4398** 4399** ^The values returned by [sqlite3_column_bytes()] and 4400** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4401** of the string. ^For clarity: the values returned by 4402** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4403** bytes in the string, not the number of characters. 4404** 4405** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4406** even empty strings, are always zero-terminated. ^The return 4407** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4408** 4409** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4410** [unprotected sqlite3_value] object. In a multithreaded environment, 4411** an unprotected sqlite3_value object may only be used safely with 4412** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4413** If the [unprotected sqlite3_value] object returned by 4414** [sqlite3_column_value()] is used in any other way, including calls 4415** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4416** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4417** Hence, the sqlite3_column_value() interface 4418** is normally only useful within the implementation of 4419** [application-defined SQL functions] or [virtual tables], not within 4420** top-level application code. 4421** 4422** The these routines may attempt to convert the datatype of the result. 4423** ^For example, if the internal representation is FLOAT and a text result 4424** is requested, [sqlite3_snprintf()] is used internally to perform the 4425** conversion automatically. ^(The following table details the conversions 4426** that are applied: 4427** 4428** <blockquote> 4429** <table border="1"> 4430** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4431** 4432** <tr><td> NULL <td> INTEGER <td> Result is 0 4433** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4434** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4435** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4436** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4437** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4438** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4439** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4440** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4441** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4442** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4443** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4444** <tr><td> TEXT <td> BLOB <td> No change 4445** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4446** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4447** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4448** </table> 4449** </blockquote>)^ 4450** 4451** Note that when type conversions occur, pointers returned by prior 4452** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4453** sqlite3_column_text16() may be invalidated. 4454** Type conversions and pointer invalidations might occur 4455** in the following cases: 4456** 4457** <ul> 4458** <li> The initial content is a BLOB and sqlite3_column_text() or 4459** sqlite3_column_text16() is called. A zero-terminator might 4460** need to be added to the string.</li> 4461** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4462** sqlite3_column_text16() is called. The content must be converted 4463** to UTF-16.</li> 4464** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4465** sqlite3_column_text() is called. The content must be converted 4466** to UTF-8.</li> 4467** </ul> 4468** 4469** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4470** not invalidate a prior pointer, though of course the content of the buffer 4471** that the prior pointer references will have been modified. Other kinds 4472** of conversion are done in place when it is possible, but sometimes they 4473** are not possible and in those cases prior pointers are invalidated. 4474** 4475** The safest policy is to invoke these routines 4476** in one of the following ways: 4477** 4478** <ul> 4479** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4480** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4481** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4482** </ul> 4483** 4484** In other words, you should call sqlite3_column_text(), 4485** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4486** into the desired format, then invoke sqlite3_column_bytes() or 4487** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4488** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4489** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4490** with calls to sqlite3_column_bytes(). 4491** 4492** ^The pointers returned are valid until a type conversion occurs as 4493** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4494** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4495** and BLOBs is freed automatically. Do not pass the pointers returned 4496** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4497** [sqlite3_free()]. 4498** 4499** ^(If a memory allocation error occurs during the evaluation of any 4500** of these routines, a default value is returned. The default value 4501** is either the integer 0, the floating point number 0.0, or a NULL 4502** pointer. Subsequent calls to [sqlite3_errcode()] will return 4503** [SQLITE_NOMEM].)^ 4504*/ 4505const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4506double sqlite3_column_double(sqlite3_stmt*, int iCol); 4507int sqlite3_column_int(sqlite3_stmt*, int iCol); 4508sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4509const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4510const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4511sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4512int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4513int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4514int sqlite3_column_type(sqlite3_stmt*, int iCol); 4515 4516/* 4517** CAPI3REF: Destroy A Prepared Statement Object 4518** DESTRUCTOR: sqlite3_stmt 4519** 4520** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4521** ^If the most recent evaluation of the statement encountered no errors 4522** or if the statement is never been evaluated, then sqlite3_finalize() returns 4523** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4524** sqlite3_finalize(S) returns the appropriate [error code] or 4525** [extended error code]. 4526** 4527** ^The sqlite3_finalize(S) routine can be called at any point during 4528** the life cycle of [prepared statement] S: 4529** before statement S is ever evaluated, after 4530** one or more calls to [sqlite3_reset()], or after any call 4531** to [sqlite3_step()] regardless of whether or not the statement has 4532** completed execution. 4533** 4534** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4535** 4536** The application must finalize every [prepared statement] in order to avoid 4537** resource leaks. It is a grievous error for the application to try to use 4538** a prepared statement after it has been finalized. Any use of a prepared 4539** statement after it has been finalized can result in undefined and 4540** undesirable behavior such as segfaults and heap corruption. 4541*/ 4542int sqlite3_finalize(sqlite3_stmt *pStmt); 4543 4544/* 4545** CAPI3REF: Reset A Prepared Statement Object 4546** METHOD: sqlite3_stmt 4547** 4548** The sqlite3_reset() function is called to reset a [prepared statement] 4549** object back to its initial state, ready to be re-executed. 4550** ^Any SQL statement variables that had values bound to them using 4551** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4552** Use [sqlite3_clear_bindings()] to reset the bindings. 4553** 4554** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4555** back to the beginning of its program. 4556** 4557** ^If the most recent call to [sqlite3_step(S)] for the 4558** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4559** or if [sqlite3_step(S)] has never before been called on S, 4560** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4561** 4562** ^If the most recent call to [sqlite3_step(S)] for the 4563** [prepared statement] S indicated an error, then 4564** [sqlite3_reset(S)] returns an appropriate [error code]. 4565** 4566** ^The [sqlite3_reset(S)] interface does not change the values 4567** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4568*/ 4569int sqlite3_reset(sqlite3_stmt *pStmt); 4570 4571/* 4572** CAPI3REF: Create Or Redefine SQL Functions 4573** KEYWORDS: {function creation routines} 4574** KEYWORDS: {application-defined SQL function} 4575** KEYWORDS: {application-defined SQL functions} 4576** METHOD: sqlite3 4577** 4578** ^These functions (collectively known as "function creation routines") 4579** are used to add SQL functions or aggregates or to redefine the behavior 4580** of existing SQL functions or aggregates. The only differences between 4581** these routines are the text encoding expected for 4582** the second parameter (the name of the function being created) 4583** and the presence or absence of a destructor callback for 4584** the application data pointer. 4585** 4586** ^The first parameter is the [database connection] to which the SQL 4587** function is to be added. ^If an application uses more than one database 4588** connection then application-defined SQL functions must be added 4589** to each database connection separately. 4590** 4591** ^The second parameter is the name of the SQL function to be created or 4592** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4593** representation, exclusive of the zero-terminator. ^Note that the name 4594** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4595** ^Any attempt to create a function with a longer name 4596** will result in [SQLITE_MISUSE] being returned. 4597** 4598** ^The third parameter (nArg) 4599** is the number of arguments that the SQL function or 4600** aggregate takes. ^If this parameter is -1, then the SQL function or 4601** aggregate may take any number of arguments between 0 and the limit 4602** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4603** parameter is less than -1 or greater than 127 then the behavior is 4604** undefined. 4605** 4606** ^The fourth parameter, eTextRep, specifies what 4607** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4608** its parameters. The application should set this parameter to 4609** [SQLITE_UTF16LE] if the function implementation invokes 4610** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4611** implementation invokes [sqlite3_value_text16be()] on an input, or 4612** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4613** otherwise. ^The same SQL function may be registered multiple times using 4614** different preferred text encodings, with different implementations for 4615** each encoding. 4616** ^When multiple implementations of the same function are available, SQLite 4617** will pick the one that involves the least amount of data conversion. 4618** 4619** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4620** to signal that the function will always return the same result given 4621** the same inputs within a single SQL statement. Most SQL functions are 4622** deterministic. The built-in [random()] SQL function is an example of a 4623** function that is not deterministic. The SQLite query planner is able to 4624** perform additional optimizations on deterministic functions, so use 4625** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4626** 4627** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4628** function can gain access to this pointer using [sqlite3_user_data()].)^ 4629** 4630** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4631** pointers to C-language functions that implement the SQL function or 4632** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4633** callback only; NULL pointers must be passed as the xStep and xFinal 4634** parameters. ^An aggregate SQL function requires an implementation of xStep 4635** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4636** SQL function or aggregate, pass NULL pointers for all three function 4637** callbacks. 4638** 4639** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4640** then it is destructor for the application data pointer. 4641** The destructor is invoked when the function is deleted, either by being 4642** overloaded or when the database connection closes.)^ 4643** ^The destructor is also invoked if the call to 4644** sqlite3_create_function_v2() fails. 4645** ^When the destructor callback of the tenth parameter is invoked, it 4646** is passed a single argument which is a copy of the application data 4647** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4648** 4649** ^It is permitted to register multiple implementations of the same 4650** functions with the same name but with either differing numbers of 4651** arguments or differing preferred text encodings. ^SQLite will use 4652** the implementation that most closely matches the way in which the 4653** SQL function is used. ^A function implementation with a non-negative 4654** nArg parameter is a better match than a function implementation with 4655** a negative nArg. ^A function where the preferred text encoding 4656** matches the database encoding is a better 4657** match than a function where the encoding is different. 4658** ^A function where the encoding difference is between UTF16le and UTF16be 4659** is a closer match than a function where the encoding difference is 4660** between UTF8 and UTF16. 4661** 4662** ^Built-in functions may be overloaded by new application-defined functions. 4663** 4664** ^An application-defined function is permitted to call other 4665** SQLite interfaces. However, such calls must not 4666** close the database connection nor finalize or reset the prepared 4667** statement in which the function is running. 4668*/ 4669int sqlite3_create_function( 4670 sqlite3 *db, 4671 const char *zFunctionName, 4672 int nArg, 4673 int eTextRep, 4674 void *pApp, 4675 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4676 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4677 void (*xFinal)(sqlite3_context*) 4678); 4679int sqlite3_create_function16( 4680 sqlite3 *db, 4681 const void *zFunctionName, 4682 int nArg, 4683 int eTextRep, 4684 void *pApp, 4685 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4686 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4687 void (*xFinal)(sqlite3_context*) 4688); 4689int sqlite3_create_function_v2( 4690 sqlite3 *db, 4691 const char *zFunctionName, 4692 int nArg, 4693 int eTextRep, 4694 void *pApp, 4695 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4696 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4697 void (*xFinal)(sqlite3_context*), 4698 void(*xDestroy)(void*) 4699); 4700 4701/* 4702** CAPI3REF: Text Encodings 4703** 4704** These constant define integer codes that represent the various 4705** text encodings supported by SQLite. 4706*/ 4707#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4708#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4709#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4710#define SQLITE_UTF16 4 /* Use native byte order */ 4711#define SQLITE_ANY 5 /* Deprecated */ 4712#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4713 4714/* 4715** CAPI3REF: Function Flags 4716** 4717** These constants may be ORed together with the 4718** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4719** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4720** [sqlite3_create_function_v2()]. 4721*/ 4722#define SQLITE_DETERMINISTIC 0x800 4723 4724/* 4725** CAPI3REF: Deprecated Functions 4726** DEPRECATED 4727** 4728** These functions are [deprecated]. In order to maintain 4729** backwards compatibility with older code, these functions continue 4730** to be supported. However, new applications should avoid 4731** the use of these functions. To encourage programmers to avoid 4732** these functions, we will not explain what they do. 4733*/ 4734#ifndef SQLITE_OMIT_DEPRECATED 4735SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4736SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4737SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4738SQLITE_DEPRECATED int sqlite3_global_recover(void); 4739SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4740SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4741 void*,sqlite3_int64); 4742#endif 4743 4744/* 4745** CAPI3REF: Obtaining SQL Values 4746** METHOD: sqlite3_value 4747** 4748** <b>Summary:</b> 4749** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4750** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4751** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4752** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4753** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4754** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4755** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4756** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4757** the native byteorder 4758** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4759** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4760** <tr><td> <td> <td> 4761** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4762** or a UTF-8 TEXT in bytes 4763** <tr><td><b>sqlite3_value_bytes16 </b> 4764** <td>→ <td>Size of UTF-16 4765** TEXT in bytes 4766** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4767** datatype of the value 4768** <tr><td><b>sqlite3_value_numeric_type </b> 4769** <td>→ <td>Best numeric datatype of the value 4770** <tr><td><b>sqlite3_value_nochange </b> 4771** <td>→ <td>True if the column is unchanged in an UPDATE 4772** against a virtual table. 4773** </table></blockquote> 4774** 4775** <b>Details:</b> 4776** 4777** These routines extract type, size, and content information from 4778** [protected sqlite3_value] objects. Protected sqlite3_value objects 4779** are used to pass parameter information into implementation of 4780** [application-defined SQL functions] and [virtual tables]. 4781** 4782** These routines work only with [protected sqlite3_value] objects. 4783** Any attempt to use these routines on an [unprotected sqlite3_value] 4784** is not threadsafe. 4785** 4786** ^These routines work just like the corresponding [column access functions] 4787** except that these routines take a single [protected sqlite3_value] object 4788** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4789** 4790** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4791** in the native byte-order of the host machine. ^The 4792** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4793** extract UTF-16 strings as big-endian and little-endian respectively. 4794** 4795** ^If [sqlite3_value] object V was initialized 4796** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4797** and if X and Y are strings that compare equal according to strcmp(X,Y), 4798** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4799** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4800** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4801** 4802** ^(The sqlite3_value_type(V) interface returns the 4803** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4804** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4805** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4806** Other interfaces might change the datatype for an sqlite3_value object. 4807** For example, if the datatype is initially SQLITE_INTEGER and 4808** sqlite3_value_text(V) is called to extract a text value for that 4809** integer, then subsequent calls to sqlite3_value_type(V) might return 4810** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4811** occurs is undefined and may change from one release of SQLite to the next. 4812** 4813** ^(The sqlite3_value_numeric_type() interface attempts to apply 4814** numeric affinity to the value. This means that an attempt is 4815** made to convert the value to an integer or floating point. If 4816** such a conversion is possible without loss of information (in other 4817** words, if the value is a string that looks like a number) 4818** then the conversion is performed. Otherwise no conversion occurs. 4819** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4820** 4821** ^Within the [xUpdate] method of a [virtual table], the 4822** sqlite3_value_nochange(X) interface returns true if and only if 4823** the column corresponding to X is unchanged by the UPDATE operation 4824** that the xUpdate method call was invoked to implement and if 4825** and the prior [xColumn] method call that was invoked to extracted 4826** the value for that column returned without setting a result (probably 4827** because it queried [sqlite3_vtab_nochange()] and found that the column 4828** was unchanging). ^Within an [xUpdate] method, any value for which 4829** sqlite3_value_nochange(X) is true will in all other respects appear 4830** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 4831** than within an [xUpdate] method call for an UPDATE statement, then 4832** the return value is arbitrary and meaningless. 4833** 4834** Please pay particular attention to the fact that the pointer returned 4835** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4836** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4837** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4838** or [sqlite3_value_text16()]. 4839** 4840** These routines must be called from the same thread as 4841** the SQL function that supplied the [sqlite3_value*] parameters. 4842*/ 4843const void *sqlite3_value_blob(sqlite3_value*); 4844double sqlite3_value_double(sqlite3_value*); 4845int sqlite3_value_int(sqlite3_value*); 4846sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4847void *sqlite3_value_pointer(sqlite3_value*, const char*); 4848const unsigned char *sqlite3_value_text(sqlite3_value*); 4849const void *sqlite3_value_text16(sqlite3_value*); 4850const void *sqlite3_value_text16le(sqlite3_value*); 4851const void *sqlite3_value_text16be(sqlite3_value*); 4852int sqlite3_value_bytes(sqlite3_value*); 4853int sqlite3_value_bytes16(sqlite3_value*); 4854int sqlite3_value_type(sqlite3_value*); 4855int sqlite3_value_numeric_type(sqlite3_value*); 4856int sqlite3_value_nochange(sqlite3_value*); 4857 4858/* 4859** CAPI3REF: Finding The Subtype Of SQL Values 4860** METHOD: sqlite3_value 4861** 4862** The sqlite3_value_subtype(V) function returns the subtype for 4863** an [application-defined SQL function] argument V. The subtype 4864** information can be used to pass a limited amount of context from 4865** one SQL function to another. Use the [sqlite3_result_subtype()] 4866** routine to set the subtype for the return value of an SQL function. 4867*/ 4868unsigned int sqlite3_value_subtype(sqlite3_value*); 4869 4870/* 4871** CAPI3REF: Copy And Free SQL Values 4872** METHOD: sqlite3_value 4873** 4874** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4875** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4876** is a [protected sqlite3_value] object even if the input is not. 4877** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4878** memory allocation fails. 4879** 4880** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4881** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4882** then sqlite3_value_free(V) is a harmless no-op. 4883*/ 4884sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4885void sqlite3_value_free(sqlite3_value*); 4886 4887/* 4888** CAPI3REF: Obtain Aggregate Function Context 4889** METHOD: sqlite3_context 4890** 4891** Implementations of aggregate SQL functions use this 4892** routine to allocate memory for storing their state. 4893** 4894** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4895** for a particular aggregate function, SQLite 4896** allocates N of memory, zeroes out that memory, and returns a pointer 4897** to the new memory. ^On second and subsequent calls to 4898** sqlite3_aggregate_context() for the same aggregate function instance, 4899** the same buffer is returned. Sqlite3_aggregate_context() is normally 4900** called once for each invocation of the xStep callback and then one 4901** last time when the xFinal callback is invoked. ^(When no rows match 4902** an aggregate query, the xStep() callback of the aggregate function 4903** implementation is never called and xFinal() is called exactly once. 4904** In those cases, sqlite3_aggregate_context() might be called for the 4905** first time from within xFinal().)^ 4906** 4907** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4908** when first called if N is less than or equal to zero or if a memory 4909** allocate error occurs. 4910** 4911** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4912** determined by the N parameter on first successful call. Changing the 4913** value of N in subsequent call to sqlite3_aggregate_context() within 4914** the same aggregate function instance will not resize the memory 4915** allocation.)^ Within the xFinal callback, it is customary to set 4916** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4917** pointless memory allocations occur. 4918** 4919** ^SQLite automatically frees the memory allocated by 4920** sqlite3_aggregate_context() when the aggregate query concludes. 4921** 4922** The first parameter must be a copy of the 4923** [sqlite3_context | SQL function context] that is the first parameter 4924** to the xStep or xFinal callback routine that implements the aggregate 4925** function. 4926** 4927** This routine must be called from the same thread in which 4928** the aggregate SQL function is running. 4929*/ 4930void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4931 4932/* 4933** CAPI3REF: User Data For Functions 4934** METHOD: sqlite3_context 4935** 4936** ^The sqlite3_user_data() interface returns a copy of 4937** the pointer that was the pUserData parameter (the 5th parameter) 4938** of the [sqlite3_create_function()] 4939** and [sqlite3_create_function16()] routines that originally 4940** registered the application defined function. 4941** 4942** This routine must be called from the same thread in which 4943** the application-defined function is running. 4944*/ 4945void *sqlite3_user_data(sqlite3_context*); 4946 4947/* 4948** CAPI3REF: Database Connection For Functions 4949** METHOD: sqlite3_context 4950** 4951** ^The sqlite3_context_db_handle() interface returns a copy of 4952** the pointer to the [database connection] (the 1st parameter) 4953** of the [sqlite3_create_function()] 4954** and [sqlite3_create_function16()] routines that originally 4955** registered the application defined function. 4956*/ 4957sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4958 4959/* 4960** CAPI3REF: Function Auxiliary Data 4961** METHOD: sqlite3_context 4962** 4963** These functions may be used by (non-aggregate) SQL functions to 4964** associate metadata with argument values. If the same value is passed to 4965** multiple invocations of the same SQL function during query execution, under 4966** some circumstances the associated metadata may be preserved. An example 4967** of where this might be useful is in a regular-expression matching 4968** function. The compiled version of the regular expression can be stored as 4969** metadata associated with the pattern string. 4970** Then as long as the pattern string remains the same, 4971** the compiled regular expression can be reused on multiple 4972** invocations of the same function. 4973** 4974** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4975** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4976** value to the application-defined function. ^N is zero for the left-most 4977** function argument. ^If there is no metadata 4978** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4979** returns a NULL pointer. 4980** 4981** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4982** argument of the application-defined function. ^Subsequent 4983** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4984** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4985** NULL if the metadata has been discarded. 4986** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4987** SQLite will invoke the destructor function X with parameter P exactly 4988** once, when the metadata is discarded. 4989** SQLite is free to discard the metadata at any time, including: <ul> 4990** <li> ^(when the corresponding function parameter changes)^, or 4991** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4992** SQL statement)^, or 4993** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4994** parameter)^, or 4995** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4996** allocation error occurs.)^ </ul> 4997** 4998** Note the last bullet in particular. The destructor X in 4999** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5000** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5001** should be called near the end of the function implementation and the 5002** function implementation should not make any use of P after 5003** sqlite3_set_auxdata() has been called. 5004** 5005** ^(In practice, metadata is preserved between function calls for 5006** function parameters that are compile-time constants, including literal 5007** values and [parameters] and expressions composed from the same.)^ 5008** 5009** The value of the N parameter to these interfaces should be non-negative. 5010** Future enhancements may make use of negative N values to define new 5011** kinds of function caching behavior. 5012** 5013** These routines must be called from the same thread in which 5014** the SQL function is running. 5015*/ 5016void *sqlite3_get_auxdata(sqlite3_context*, int N); 5017void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5018 5019 5020/* 5021** CAPI3REF: Constants Defining Special Destructor Behavior 5022** 5023** These are special values for the destructor that is passed in as the 5024** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5025** argument is SQLITE_STATIC, it means that the content pointer is constant 5026** and will never change. It does not need to be destroyed. ^The 5027** SQLITE_TRANSIENT value means that the content will likely change in 5028** the near future and that SQLite should make its own private copy of 5029** the content before returning. 5030** 5031** The typedef is necessary to work around problems in certain 5032** C++ compilers. 5033*/ 5034typedef void (*sqlite3_destructor_type)(void*); 5035#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5036#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5037 5038/* 5039** CAPI3REF: Setting The Result Of An SQL Function 5040** METHOD: sqlite3_context 5041** 5042** These routines are used by the xFunc or xFinal callbacks that 5043** implement SQL functions and aggregates. See 5044** [sqlite3_create_function()] and [sqlite3_create_function16()] 5045** for additional information. 5046** 5047** These functions work very much like the [parameter binding] family of 5048** functions used to bind values to host parameters in prepared statements. 5049** Refer to the [SQL parameter] documentation for additional information. 5050** 5051** ^The sqlite3_result_blob() interface sets the result from 5052** an application-defined function to be the BLOB whose content is pointed 5053** to by the second parameter and which is N bytes long where N is the 5054** third parameter. 5055** 5056** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5057** interfaces set the result of the application-defined function to be 5058** a BLOB containing all zero bytes and N bytes in size. 5059** 5060** ^The sqlite3_result_double() interface sets the result from 5061** an application-defined function to be a floating point value specified 5062** by its 2nd argument. 5063** 5064** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5065** cause the implemented SQL function to throw an exception. 5066** ^SQLite uses the string pointed to by the 5067** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5068** as the text of an error message. ^SQLite interprets the error 5069** message string from sqlite3_result_error() as UTF-8. ^SQLite 5070** interprets the string from sqlite3_result_error16() as UTF-16 in native 5071** byte order. ^If the third parameter to sqlite3_result_error() 5072** or sqlite3_result_error16() is negative then SQLite takes as the error 5073** message all text up through the first zero character. 5074** ^If the third parameter to sqlite3_result_error() or 5075** sqlite3_result_error16() is non-negative then SQLite takes that many 5076** bytes (not characters) from the 2nd parameter as the error message. 5077** ^The sqlite3_result_error() and sqlite3_result_error16() 5078** routines make a private copy of the error message text before 5079** they return. Hence, the calling function can deallocate or 5080** modify the text after they return without harm. 5081** ^The sqlite3_result_error_code() function changes the error code 5082** returned by SQLite as a result of an error in a function. ^By default, 5083** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5084** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5085** 5086** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5087** error indicating that a string or BLOB is too long to represent. 5088** 5089** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5090** error indicating that a memory allocation failed. 5091** 5092** ^The sqlite3_result_int() interface sets the return value 5093** of the application-defined function to be the 32-bit signed integer 5094** value given in the 2nd argument. 5095** ^The sqlite3_result_int64() interface sets the return value 5096** of the application-defined function to be the 64-bit signed integer 5097** value given in the 2nd argument. 5098** 5099** ^The sqlite3_result_null() interface sets the return value 5100** of the application-defined function to be NULL. 5101** 5102** ^The sqlite3_result_text(), sqlite3_result_text16(), 5103** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5104** set the return value of the application-defined function to be 5105** a text string which is represented as UTF-8, UTF-16 native byte order, 5106** UTF-16 little endian, or UTF-16 big endian, respectively. 5107** ^The sqlite3_result_text64() interface sets the return value of an 5108** application-defined function to be a text string in an encoding 5109** specified by the fifth (and last) parameter, which must be one 5110** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5111** ^SQLite takes the text result from the application from 5112** the 2nd parameter of the sqlite3_result_text* interfaces. 5113** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5114** is negative, then SQLite takes result text from the 2nd parameter 5115** through the first zero character. 5116** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5117** is non-negative, then as many bytes (not characters) of the text 5118** pointed to by the 2nd parameter are taken as the application-defined 5119** function result. If the 3rd parameter is non-negative, then it 5120** must be the byte offset into the string where the NUL terminator would 5121** appear if the string where NUL terminated. If any NUL characters occur 5122** in the string at a byte offset that is less than the value of the 3rd 5123** parameter, then the resulting string will contain embedded NULs and the 5124** result of expressions operating on strings with embedded NULs is undefined. 5125** ^If the 4th parameter to the sqlite3_result_text* interfaces 5126** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5127** function as the destructor on the text or BLOB result when it has 5128** finished using that result. 5129** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5130** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5131** assumes that the text or BLOB result is in constant space and does not 5132** copy the content of the parameter nor call a destructor on the content 5133** when it has finished using that result. 5134** ^If the 4th parameter to the sqlite3_result_text* interfaces 5135** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5136** then SQLite makes a copy of the result into space obtained 5137** from [sqlite3_malloc()] before it returns. 5138** 5139** ^The sqlite3_result_value() interface sets the result of 5140** the application-defined function to be a copy of the 5141** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5142** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5143** so that the [sqlite3_value] specified in the parameter may change or 5144** be deallocated after sqlite3_result_value() returns without harm. 5145** ^A [protected sqlite3_value] object may always be used where an 5146** [unprotected sqlite3_value] object is required, so either 5147** kind of [sqlite3_value] object can be used with this interface. 5148** 5149** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5150** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5151** also associates the host-language pointer P or type T with that 5152** NULL value such that the pointer can be retrieved within an 5153** [application-defined SQL function] using [sqlite3_value_pointer()]. 5154** ^If the D parameter is not NULL, then it is a pointer to a destructor 5155** for the P parameter. ^SQLite invokes D with P as its only argument 5156** when SQLite is finished with P. The T parameter should be a static 5157** string and preferably a string literal. The sqlite3_result_pointer() 5158** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5159** 5160** If these routines are called from within the different thread 5161** than the one containing the application-defined function that received 5162** the [sqlite3_context] pointer, the results are undefined. 5163*/ 5164void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5165void sqlite3_result_blob64(sqlite3_context*,const void*, 5166 sqlite3_uint64,void(*)(void*)); 5167void sqlite3_result_double(sqlite3_context*, double); 5168void sqlite3_result_error(sqlite3_context*, const char*, int); 5169void sqlite3_result_error16(sqlite3_context*, const void*, int); 5170void sqlite3_result_error_toobig(sqlite3_context*); 5171void sqlite3_result_error_nomem(sqlite3_context*); 5172void sqlite3_result_error_code(sqlite3_context*, int); 5173void sqlite3_result_int(sqlite3_context*, int); 5174void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5175void sqlite3_result_null(sqlite3_context*); 5176void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5177void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5178 void(*)(void*), unsigned char encoding); 5179void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5180void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5181void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5182void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5183void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5184void sqlite3_result_zeroblob(sqlite3_context*, int n); 5185int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5186 5187 5188/* 5189** CAPI3REF: Setting The Subtype Of An SQL Function 5190** METHOD: sqlite3_context 5191** 5192** The sqlite3_result_subtype(C,T) function causes the subtype of 5193** the result from the [application-defined SQL function] with 5194** [sqlite3_context] C to be the value T. Only the lower 8 bits 5195** of the subtype T are preserved in current versions of SQLite; 5196** higher order bits are discarded. 5197** The number of subtype bytes preserved by SQLite might increase 5198** in future releases of SQLite. 5199*/ 5200void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5201 5202/* 5203** CAPI3REF: Define New Collating Sequences 5204** METHOD: sqlite3 5205** 5206** ^These functions add, remove, or modify a [collation] associated 5207** with the [database connection] specified as the first argument. 5208** 5209** ^The name of the collation is a UTF-8 string 5210** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5211** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5212** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5213** considered to be the same name. 5214** 5215** ^(The third argument (eTextRep) must be one of the constants: 5216** <ul> 5217** <li> [SQLITE_UTF8], 5218** <li> [SQLITE_UTF16LE], 5219** <li> [SQLITE_UTF16BE], 5220** <li> [SQLITE_UTF16], or 5221** <li> [SQLITE_UTF16_ALIGNED]. 5222** </ul>)^ 5223** ^The eTextRep argument determines the encoding of strings passed 5224** to the collating function callback, xCallback. 5225** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5226** force strings to be UTF16 with native byte order. 5227** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5228** on an even byte address. 5229** 5230** ^The fourth argument, pArg, is an application data pointer that is passed 5231** through as the first argument to the collating function callback. 5232** 5233** ^The fifth argument, xCallback, is a pointer to the collating function. 5234** ^Multiple collating functions can be registered using the same name but 5235** with different eTextRep parameters and SQLite will use whichever 5236** function requires the least amount of data transformation. 5237** ^If the xCallback argument is NULL then the collating function is 5238** deleted. ^When all collating functions having the same name are deleted, 5239** that collation is no longer usable. 5240** 5241** ^The collating function callback is invoked with a copy of the pArg 5242** application data pointer and with two strings in the encoding specified 5243** by the eTextRep argument. The collating function must return an 5244** integer that is negative, zero, or positive 5245** if the first string is less than, equal to, or greater than the second, 5246** respectively. A collating function must always return the same answer 5247** given the same inputs. If two or more collating functions are registered 5248** to the same collation name (using different eTextRep values) then all 5249** must give an equivalent answer when invoked with equivalent strings. 5250** The collating function must obey the following properties for all 5251** strings A, B, and C: 5252** 5253** <ol> 5254** <li> If A==B then B==A. 5255** <li> If A==B and B==C then A==C. 5256** <li> If A<B THEN B>A. 5257** <li> If A<B and B<C then A<C. 5258** </ol> 5259** 5260** If a collating function fails any of the above constraints and that 5261** collating function is registered and used, then the behavior of SQLite 5262** is undefined. 5263** 5264** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5265** with the addition that the xDestroy callback is invoked on pArg when 5266** the collating function is deleted. 5267** ^Collating functions are deleted when they are overridden by later 5268** calls to the collation creation functions or when the 5269** [database connection] is closed using [sqlite3_close()]. 5270** 5271** ^The xDestroy callback is <u>not</u> called if the 5272** sqlite3_create_collation_v2() function fails. Applications that invoke 5273** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5274** check the return code and dispose of the application data pointer 5275** themselves rather than expecting SQLite to deal with it for them. 5276** This is different from every other SQLite interface. The inconsistency 5277** is unfortunate but cannot be changed without breaking backwards 5278** compatibility. 5279** 5280** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5281*/ 5282int sqlite3_create_collation( 5283 sqlite3*, 5284 const char *zName, 5285 int eTextRep, 5286 void *pArg, 5287 int(*xCompare)(void*,int,const void*,int,const void*) 5288); 5289int sqlite3_create_collation_v2( 5290 sqlite3*, 5291 const char *zName, 5292 int eTextRep, 5293 void *pArg, 5294 int(*xCompare)(void*,int,const void*,int,const void*), 5295 void(*xDestroy)(void*) 5296); 5297int sqlite3_create_collation16( 5298 sqlite3*, 5299 const void *zName, 5300 int eTextRep, 5301 void *pArg, 5302 int(*xCompare)(void*,int,const void*,int,const void*) 5303); 5304 5305/* 5306** CAPI3REF: Collation Needed Callbacks 5307** METHOD: sqlite3 5308** 5309** ^To avoid having to register all collation sequences before a database 5310** can be used, a single callback function may be registered with the 5311** [database connection] to be invoked whenever an undefined collation 5312** sequence is required. 5313** 5314** ^If the function is registered using the sqlite3_collation_needed() API, 5315** then it is passed the names of undefined collation sequences as strings 5316** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5317** the names are passed as UTF-16 in machine native byte order. 5318** ^A call to either function replaces the existing collation-needed callback. 5319** 5320** ^(When the callback is invoked, the first argument passed is a copy 5321** of the second argument to sqlite3_collation_needed() or 5322** sqlite3_collation_needed16(). The second argument is the database 5323** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5324** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5325** sequence function required. The fourth parameter is the name of the 5326** required collation sequence.)^ 5327** 5328** The callback function should register the desired collation using 5329** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5330** [sqlite3_create_collation_v2()]. 5331*/ 5332int sqlite3_collation_needed( 5333 sqlite3*, 5334 void*, 5335 void(*)(void*,sqlite3*,int eTextRep,const char*) 5336); 5337int sqlite3_collation_needed16( 5338 sqlite3*, 5339 void*, 5340 void(*)(void*,sqlite3*,int eTextRep,const void*) 5341); 5342 5343#ifdef SQLITE_HAS_CODEC 5344/* 5345** Specify the key for an encrypted database. This routine should be 5346** called right after sqlite3_open(). 5347** 5348** The code to implement this API is not available in the public release 5349** of SQLite. 5350*/ 5351int sqlite3_key( 5352 sqlite3 *db, /* Database to be rekeyed */ 5353 const void *pKey, int nKey /* The key */ 5354); 5355int sqlite3_key_v2( 5356 sqlite3 *db, /* Database to be rekeyed */ 5357 const char *zDbName, /* Name of the database */ 5358 const void *pKey, int nKey /* The key */ 5359); 5360 5361/* 5362** Change the key on an open database. If the current database is not 5363** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5364** database is decrypted. 5365** 5366** The code to implement this API is not available in the public release 5367** of SQLite. 5368*/ 5369int sqlite3_rekey( 5370 sqlite3 *db, /* Database to be rekeyed */ 5371 const void *pKey, int nKey /* The new key */ 5372); 5373int sqlite3_rekey_v2( 5374 sqlite3 *db, /* Database to be rekeyed */ 5375 const char *zDbName, /* Name of the database */ 5376 const void *pKey, int nKey /* The new key */ 5377); 5378 5379/* 5380** Specify the activation key for a SEE database. Unless 5381** activated, none of the SEE routines will work. 5382*/ 5383void sqlite3_activate_see( 5384 const char *zPassPhrase /* Activation phrase */ 5385); 5386#endif 5387 5388#ifdef SQLITE_ENABLE_CEROD 5389/* 5390** Specify the activation key for a CEROD database. Unless 5391** activated, none of the CEROD routines will work. 5392*/ 5393void sqlite3_activate_cerod( 5394 const char *zPassPhrase /* Activation phrase */ 5395); 5396#endif 5397 5398/* 5399** CAPI3REF: Suspend Execution For A Short Time 5400** 5401** The sqlite3_sleep() function causes the current thread to suspend execution 5402** for at least a number of milliseconds specified in its parameter. 5403** 5404** If the operating system does not support sleep requests with 5405** millisecond time resolution, then the time will be rounded up to 5406** the nearest second. The number of milliseconds of sleep actually 5407** requested from the operating system is returned. 5408** 5409** ^SQLite implements this interface by calling the xSleep() 5410** method of the default [sqlite3_vfs] object. If the xSleep() method 5411** of the default VFS is not implemented correctly, or not implemented at 5412** all, then the behavior of sqlite3_sleep() may deviate from the description 5413** in the previous paragraphs. 5414*/ 5415int sqlite3_sleep(int); 5416 5417/* 5418** CAPI3REF: Name Of The Folder Holding Temporary Files 5419** 5420** ^(If this global variable is made to point to a string which is 5421** the name of a folder (a.k.a. directory), then all temporary files 5422** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5423** will be placed in that directory.)^ ^If this variable 5424** is a NULL pointer, then SQLite performs a search for an appropriate 5425** temporary file directory. 5426** 5427** Applications are strongly discouraged from using this global variable. 5428** It is required to set a temporary folder on Windows Runtime (WinRT). 5429** But for all other platforms, it is highly recommended that applications 5430** neither read nor write this variable. This global variable is a relic 5431** that exists for backwards compatibility of legacy applications and should 5432** be avoided in new projects. 5433** 5434** It is not safe to read or modify this variable in more than one 5435** thread at a time. It is not safe to read or modify this variable 5436** if a [database connection] is being used at the same time in a separate 5437** thread. 5438** It is intended that this variable be set once 5439** as part of process initialization and before any SQLite interface 5440** routines have been called and that this variable remain unchanged 5441** thereafter. 5442** 5443** ^The [temp_store_directory pragma] may modify this variable and cause 5444** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5445** the [temp_store_directory pragma] always assumes that any string 5446** that this variable points to is held in memory obtained from 5447** [sqlite3_malloc] and the pragma may attempt to free that memory 5448** using [sqlite3_free]. 5449** Hence, if this variable is modified directly, either it should be 5450** made NULL or made to point to memory obtained from [sqlite3_malloc] 5451** or else the use of the [temp_store_directory pragma] should be avoided. 5452** Except when requested by the [temp_store_directory pragma], SQLite 5453** does not free the memory that sqlite3_temp_directory points to. If 5454** the application wants that memory to be freed, it must do 5455** so itself, taking care to only do so after all [database connection] 5456** objects have been destroyed. 5457** 5458** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5459** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5460** features that require the use of temporary files may fail. Here is an 5461** example of how to do this using C++ with the Windows Runtime: 5462** 5463** <blockquote><pre> 5464** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5465** TemporaryFolder->Path->Data(); 5466** char zPathBuf[MAX_PATH + 1]; 5467** memset(zPathBuf, 0, sizeof(zPathBuf)); 5468** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5469** NULL, NULL); 5470** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5471** </pre></blockquote> 5472*/ 5473SQLITE_EXTERN char *sqlite3_temp_directory; 5474 5475/* 5476** CAPI3REF: Name Of The Folder Holding Database Files 5477** 5478** ^(If this global variable is made to point to a string which is 5479** the name of a folder (a.k.a. directory), then all database files 5480** specified with a relative pathname and created or accessed by 5481** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5482** to be relative to that directory.)^ ^If this variable is a NULL 5483** pointer, then SQLite assumes that all database files specified 5484** with a relative pathname are relative to the current directory 5485** for the process. Only the windows VFS makes use of this global 5486** variable; it is ignored by the unix VFS. 5487** 5488** Changing the value of this variable while a database connection is 5489** open can result in a corrupt database. 5490** 5491** It is not safe to read or modify this variable in more than one 5492** thread at a time. It is not safe to read or modify this variable 5493** if a [database connection] is being used at the same time in a separate 5494** thread. 5495** It is intended that this variable be set once 5496** as part of process initialization and before any SQLite interface 5497** routines have been called and that this variable remain unchanged 5498** thereafter. 5499** 5500** ^The [data_store_directory pragma] may modify this variable and cause 5501** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5502** the [data_store_directory pragma] always assumes that any string 5503** that this variable points to is held in memory obtained from 5504** [sqlite3_malloc] and the pragma may attempt to free that memory 5505** using [sqlite3_free]. 5506** Hence, if this variable is modified directly, either it should be 5507** made NULL or made to point to memory obtained from [sqlite3_malloc] 5508** or else the use of the [data_store_directory pragma] should be avoided. 5509*/ 5510SQLITE_EXTERN char *sqlite3_data_directory; 5511 5512/* 5513** CAPI3REF: Test For Auto-Commit Mode 5514** KEYWORDS: {autocommit mode} 5515** METHOD: sqlite3 5516** 5517** ^The sqlite3_get_autocommit() interface returns non-zero or 5518** zero if the given database connection is or is not in autocommit mode, 5519** respectively. ^Autocommit mode is on by default. 5520** ^Autocommit mode is disabled by a [BEGIN] statement. 5521** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5522** 5523** If certain kinds of errors occur on a statement within a multi-statement 5524** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5525** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5526** transaction might be rolled back automatically. The only way to 5527** find out whether SQLite automatically rolled back the transaction after 5528** an error is to use this function. 5529** 5530** If another thread changes the autocommit status of the database 5531** connection while this routine is running, then the return value 5532** is undefined. 5533*/ 5534int sqlite3_get_autocommit(sqlite3*); 5535 5536/* 5537** CAPI3REF: Find The Database Handle Of A Prepared Statement 5538** METHOD: sqlite3_stmt 5539** 5540** ^The sqlite3_db_handle interface returns the [database connection] handle 5541** to which a [prepared statement] belongs. ^The [database connection] 5542** returned by sqlite3_db_handle is the same [database connection] 5543** that was the first argument 5544** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5545** create the statement in the first place. 5546*/ 5547sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5548 5549/* 5550** CAPI3REF: Return The Filename For A Database Connection 5551** METHOD: sqlite3 5552** 5553** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5554** associated with database N of connection D. ^The main database file 5555** has the name "main". If there is no attached database N on the database 5556** connection D, or if database N is a temporary or in-memory database, then 5557** a NULL pointer is returned. 5558** 5559** ^The filename returned by this function is the output of the 5560** xFullPathname method of the [VFS]. ^In other words, the filename 5561** will be an absolute pathname, even if the filename used 5562** to open the database originally was a URI or relative pathname. 5563*/ 5564const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5565 5566/* 5567** CAPI3REF: Determine if a database is read-only 5568** METHOD: sqlite3 5569** 5570** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5571** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5572** the name of a database on connection D. 5573*/ 5574int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5575 5576/* 5577** CAPI3REF: Find the next prepared statement 5578** METHOD: sqlite3 5579** 5580** ^This interface returns a pointer to the next [prepared statement] after 5581** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5582** then this interface returns a pointer to the first prepared statement 5583** associated with the database connection pDb. ^If no prepared statement 5584** satisfies the conditions of this routine, it returns NULL. 5585** 5586** The [database connection] pointer D in a call to 5587** [sqlite3_next_stmt(D,S)] must refer to an open database 5588** connection and in particular must not be a NULL pointer. 5589*/ 5590sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5591 5592/* 5593** CAPI3REF: Commit And Rollback Notification Callbacks 5594** METHOD: sqlite3 5595** 5596** ^The sqlite3_commit_hook() interface registers a callback 5597** function to be invoked whenever a transaction is [COMMIT | committed]. 5598** ^Any callback set by a previous call to sqlite3_commit_hook() 5599** for the same database connection is overridden. 5600** ^The sqlite3_rollback_hook() interface registers a callback 5601** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5602** ^Any callback set by a previous call to sqlite3_rollback_hook() 5603** for the same database connection is overridden. 5604** ^The pArg argument is passed through to the callback. 5605** ^If the callback on a commit hook function returns non-zero, 5606** then the commit is converted into a rollback. 5607** 5608** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5609** return the P argument from the previous call of the same function 5610** on the same [database connection] D, or NULL for 5611** the first call for each function on D. 5612** 5613** The commit and rollback hook callbacks are not reentrant. 5614** The callback implementation must not do anything that will modify 5615** the database connection that invoked the callback. Any actions 5616** to modify the database connection must be deferred until after the 5617** completion of the [sqlite3_step()] call that triggered the commit 5618** or rollback hook in the first place. 5619** Note that running any other SQL statements, including SELECT statements, 5620** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5621** the database connections for the meaning of "modify" in this paragraph. 5622** 5623** ^Registering a NULL function disables the callback. 5624** 5625** ^When the commit hook callback routine returns zero, the [COMMIT] 5626** operation is allowed to continue normally. ^If the commit hook 5627** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5628** ^The rollback hook is invoked on a rollback that results from a commit 5629** hook returning non-zero, just as it would be with any other rollback. 5630** 5631** ^For the purposes of this API, a transaction is said to have been 5632** rolled back if an explicit "ROLLBACK" statement is executed, or 5633** an error or constraint causes an implicit rollback to occur. 5634** ^The rollback callback is not invoked if a transaction is 5635** automatically rolled back because the database connection is closed. 5636** 5637** See also the [sqlite3_update_hook()] interface. 5638*/ 5639void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5640void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5641 5642/* 5643** CAPI3REF: Data Change Notification Callbacks 5644** METHOD: sqlite3 5645** 5646** ^The sqlite3_update_hook() interface registers a callback function 5647** with the [database connection] identified by the first argument 5648** to be invoked whenever a row is updated, inserted or deleted in 5649** a [rowid table]. 5650** ^Any callback set by a previous call to this function 5651** for the same database connection is overridden. 5652** 5653** ^The second argument is a pointer to the function to invoke when a 5654** row is updated, inserted or deleted in a rowid table. 5655** ^The first argument to the callback is a copy of the third argument 5656** to sqlite3_update_hook(). 5657** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5658** or [SQLITE_UPDATE], depending on the operation that caused the callback 5659** to be invoked. 5660** ^The third and fourth arguments to the callback contain pointers to the 5661** database and table name containing the affected row. 5662** ^The final callback parameter is the [rowid] of the row. 5663** ^In the case of an update, this is the [rowid] after the update takes place. 5664** 5665** ^(The update hook is not invoked when internal system tables are 5666** modified (i.e. sqlite_master and sqlite_sequence).)^ 5667** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5668** 5669** ^In the current implementation, the update hook 5670** is not invoked when conflicting rows are deleted because of an 5671** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5672** invoked when rows are deleted using the [truncate optimization]. 5673** The exceptions defined in this paragraph might change in a future 5674** release of SQLite. 5675** 5676** The update hook implementation must not do anything that will modify 5677** the database connection that invoked the update hook. Any actions 5678** to modify the database connection must be deferred until after the 5679** completion of the [sqlite3_step()] call that triggered the update hook. 5680** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5681** database connections for the meaning of "modify" in this paragraph. 5682** 5683** ^The sqlite3_update_hook(D,C,P) function 5684** returns the P argument from the previous call 5685** on the same [database connection] D, or NULL for 5686** the first call on D. 5687** 5688** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5689** and [sqlite3_preupdate_hook()] interfaces. 5690*/ 5691void *sqlite3_update_hook( 5692 sqlite3*, 5693 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5694 void* 5695); 5696 5697/* 5698** CAPI3REF: Enable Or Disable Shared Pager Cache 5699** 5700** ^(This routine enables or disables the sharing of the database cache 5701** and schema data structures between [database connection | connections] 5702** to the same database. Sharing is enabled if the argument is true 5703** and disabled if the argument is false.)^ 5704** 5705** ^Cache sharing is enabled and disabled for an entire process. 5706** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5707** In prior versions of SQLite, 5708** sharing was enabled or disabled for each thread separately. 5709** 5710** ^(The cache sharing mode set by this interface effects all subsequent 5711** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5712** Existing database connections continue use the sharing mode 5713** that was in effect at the time they were opened.)^ 5714** 5715** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5716** successfully. An [error code] is returned otherwise.)^ 5717** 5718** ^Shared cache is disabled by default. But this might change in 5719** future releases of SQLite. Applications that care about shared 5720** cache setting should set it explicitly. 5721** 5722** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5723** and will always return SQLITE_MISUSE. On those systems, 5724** shared cache mode should be enabled per-database connection via 5725** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5726** 5727** This interface is threadsafe on processors where writing a 5728** 32-bit integer is atomic. 5729** 5730** See Also: [SQLite Shared-Cache Mode] 5731*/ 5732int sqlite3_enable_shared_cache(int); 5733 5734/* 5735** CAPI3REF: Attempt To Free Heap Memory 5736** 5737** ^The sqlite3_release_memory() interface attempts to free N bytes 5738** of heap memory by deallocating non-essential memory allocations 5739** held by the database library. Memory used to cache database 5740** pages to improve performance is an example of non-essential memory. 5741** ^sqlite3_release_memory() returns the number of bytes actually freed, 5742** which might be more or less than the amount requested. 5743** ^The sqlite3_release_memory() routine is a no-op returning zero 5744** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5745** 5746** See also: [sqlite3_db_release_memory()] 5747*/ 5748int sqlite3_release_memory(int); 5749 5750/* 5751** CAPI3REF: Free Memory Used By A Database Connection 5752** METHOD: sqlite3 5753** 5754** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5755** memory as possible from database connection D. Unlike the 5756** [sqlite3_release_memory()] interface, this interface is in effect even 5757** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5758** omitted. 5759** 5760** See also: [sqlite3_release_memory()] 5761*/ 5762int sqlite3_db_release_memory(sqlite3*); 5763 5764/* 5765** CAPI3REF: Impose A Limit On Heap Size 5766** 5767** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5768** soft limit on the amount of heap memory that may be allocated by SQLite. 5769** ^SQLite strives to keep heap memory utilization below the soft heap 5770** limit by reducing the number of pages held in the page cache 5771** as heap memory usages approaches the limit. 5772** ^The soft heap limit is "soft" because even though SQLite strives to stay 5773** below the limit, it will exceed the limit rather than generate 5774** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5775** is advisory only. 5776** 5777** ^The return value from sqlite3_soft_heap_limit64() is the size of 5778** the soft heap limit prior to the call, or negative in the case of an 5779** error. ^If the argument N is negative 5780** then no change is made to the soft heap limit. Hence, the current 5781** size of the soft heap limit can be determined by invoking 5782** sqlite3_soft_heap_limit64() with a negative argument. 5783** 5784** ^If the argument N is zero then the soft heap limit is disabled. 5785** 5786** ^(The soft heap limit is not enforced in the current implementation 5787** if one or more of following conditions are true: 5788** 5789** <ul> 5790** <li> The soft heap limit is set to zero. 5791** <li> Memory accounting is disabled using a combination of the 5792** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5793** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5794** <li> An alternative page cache implementation is specified using 5795** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5796** <li> The page cache allocates from its own memory pool supplied 5797** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5798** from the heap. 5799** </ul>)^ 5800** 5801** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5802** the soft heap limit is enforced 5803** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5804** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5805** the soft heap limit is enforced on every memory allocation. Without 5806** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5807** when memory is allocated by the page cache. Testing suggests that because 5808** the page cache is the predominate memory user in SQLite, most 5809** applications will achieve adequate soft heap limit enforcement without 5810** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5811** 5812** The circumstances under which SQLite will enforce the soft heap limit may 5813** changes in future releases of SQLite. 5814*/ 5815sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5816 5817/* 5818** CAPI3REF: Deprecated Soft Heap Limit Interface 5819** DEPRECATED 5820** 5821** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5822** interface. This routine is provided for historical compatibility 5823** only. All new applications should use the 5824** [sqlite3_soft_heap_limit64()] interface rather than this one. 5825*/ 5826SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5827 5828 5829/* 5830** CAPI3REF: Extract Metadata About A Column Of A Table 5831** METHOD: sqlite3 5832** 5833** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5834** information about column C of table T in database D 5835** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5836** interface returns SQLITE_OK and fills in the non-NULL pointers in 5837** the final five arguments with appropriate values if the specified 5838** column exists. ^The sqlite3_table_column_metadata() interface returns 5839** SQLITE_ERROR and if the specified column does not exist. 5840** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5841** NULL pointer, then this routine simply checks for the existence of the 5842** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5843** does not. If the table name parameter T in a call to 5844** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5845** undefined behavior. 5846** 5847** ^The column is identified by the second, third and fourth parameters to 5848** this function. ^(The second parameter is either the name of the database 5849** (i.e. "main", "temp", or an attached database) containing the specified 5850** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5851** for the table using the same algorithm used by the database engine to 5852** resolve unqualified table references. 5853** 5854** ^The third and fourth parameters to this function are the table and column 5855** name of the desired column, respectively. 5856** 5857** ^Metadata is returned by writing to the memory locations passed as the 5th 5858** and subsequent parameters to this function. ^Any of these arguments may be 5859** NULL, in which case the corresponding element of metadata is omitted. 5860** 5861** ^(<blockquote> 5862** <table border="1"> 5863** <tr><th> Parameter <th> Output<br>Type <th> Description 5864** 5865** <tr><td> 5th <td> const char* <td> Data type 5866** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5867** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5868** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5869** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5870** </table> 5871** </blockquote>)^ 5872** 5873** ^The memory pointed to by the character pointers returned for the 5874** declaration type and collation sequence is valid until the next 5875** call to any SQLite API function. 5876** 5877** ^If the specified table is actually a view, an [error code] is returned. 5878** 5879** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5880** is not a [WITHOUT ROWID] table and an 5881** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5882** parameters are set for the explicitly declared column. ^(If there is no 5883** [INTEGER PRIMARY KEY] column, then the outputs 5884** for the [rowid] are set as follows: 5885** 5886** <pre> 5887** data type: "INTEGER" 5888** collation sequence: "BINARY" 5889** not null: 0 5890** primary key: 1 5891** auto increment: 0 5892** </pre>)^ 5893** 5894** ^This function causes all database schemas to be read from disk and 5895** parsed, if that has not already been done, and returns an error if 5896** any errors are encountered while loading the schema. 5897*/ 5898int sqlite3_table_column_metadata( 5899 sqlite3 *db, /* Connection handle */ 5900 const char *zDbName, /* Database name or NULL */ 5901 const char *zTableName, /* Table name */ 5902 const char *zColumnName, /* Column name */ 5903 char const **pzDataType, /* OUTPUT: Declared data type */ 5904 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5905 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5906 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5907 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5908); 5909 5910/* 5911** CAPI3REF: Load An Extension 5912** METHOD: sqlite3 5913** 5914** ^This interface loads an SQLite extension library from the named file. 5915** 5916** ^The sqlite3_load_extension() interface attempts to load an 5917** [SQLite extension] library contained in the file zFile. If 5918** the file cannot be loaded directly, attempts are made to load 5919** with various operating-system specific extensions added. 5920** So for example, if "samplelib" cannot be loaded, then names like 5921** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5922** be tried also. 5923** 5924** ^The entry point is zProc. 5925** ^(zProc may be 0, in which case SQLite will try to come up with an 5926** entry point name on its own. It first tries "sqlite3_extension_init". 5927** If that does not work, it constructs a name "sqlite3_X_init" where the 5928** X is consists of the lower-case equivalent of all ASCII alphabetic 5929** characters in the filename from the last "/" to the first following 5930** "." and omitting any initial "lib".)^ 5931** ^The sqlite3_load_extension() interface returns 5932** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5933** ^If an error occurs and pzErrMsg is not 0, then the 5934** [sqlite3_load_extension()] interface shall attempt to 5935** fill *pzErrMsg with error message text stored in memory 5936** obtained from [sqlite3_malloc()]. The calling function 5937** should free this memory by calling [sqlite3_free()]. 5938** 5939** ^Extension loading must be enabled using 5940** [sqlite3_enable_load_extension()] or 5941** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5942** prior to calling this API, 5943** otherwise an error will be returned. 5944** 5945** <b>Security warning:</b> It is recommended that the 5946** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5947** interface. The use of the [sqlite3_enable_load_extension()] interface 5948** should be avoided. This will keep the SQL function [load_extension()] 5949** disabled and prevent SQL injections from giving attackers 5950** access to extension loading capabilities. 5951** 5952** See also the [load_extension() SQL function]. 5953*/ 5954int sqlite3_load_extension( 5955 sqlite3 *db, /* Load the extension into this database connection */ 5956 const char *zFile, /* Name of the shared library containing extension */ 5957 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5958 char **pzErrMsg /* Put error message here if not 0 */ 5959); 5960 5961/* 5962** CAPI3REF: Enable Or Disable Extension Loading 5963** METHOD: sqlite3 5964** 5965** ^So as not to open security holes in older applications that are 5966** unprepared to deal with [extension loading], and as a means of disabling 5967** [extension loading] while evaluating user-entered SQL, the following API 5968** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5969** 5970** ^Extension loading is off by default. 5971** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5972** to turn extension loading on and call it with onoff==0 to turn 5973** it back off again. 5974** 5975** ^This interface enables or disables both the C-API 5976** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5977** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5978** to enable or disable only the C-API.)^ 5979** 5980** <b>Security warning:</b> It is recommended that extension loading 5981** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5982** rather than this interface, so the [load_extension()] SQL function 5983** remains disabled. This will prevent SQL injections from giving attackers 5984** access to extension loading capabilities. 5985*/ 5986int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5987 5988/* 5989** CAPI3REF: Automatically Load Statically Linked Extensions 5990** 5991** ^This interface causes the xEntryPoint() function to be invoked for 5992** each new [database connection] that is created. The idea here is that 5993** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5994** that is to be automatically loaded into all new database connections. 5995** 5996** ^(Even though the function prototype shows that xEntryPoint() takes 5997** no arguments and returns void, SQLite invokes xEntryPoint() with three 5998** arguments and expects an integer result as if the signature of the 5999** entry point where as follows: 6000** 6001** <blockquote><pre> 6002** int xEntryPoint( 6003** sqlite3 *db, 6004** const char **pzErrMsg, 6005** const struct sqlite3_api_routines *pThunk 6006** ); 6007** </pre></blockquote>)^ 6008** 6009** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6010** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6011** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6012** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6013** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6014** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6015** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6016** 6017** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6018** on the list of automatic extensions is a harmless no-op. ^No entry point 6019** will be called more than once for each database connection that is opened. 6020** 6021** See also: [sqlite3_reset_auto_extension()] 6022** and [sqlite3_cancel_auto_extension()] 6023*/ 6024int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6025 6026/* 6027** CAPI3REF: Cancel Automatic Extension Loading 6028** 6029** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6030** initialization routine X that was registered using a prior call to 6031** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6032** routine returns 1 if initialization routine X was successfully 6033** unregistered and it returns 0 if X was not on the list of initialization 6034** routines. 6035*/ 6036int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6037 6038/* 6039** CAPI3REF: Reset Automatic Extension Loading 6040** 6041** ^This interface disables all automatic extensions previously 6042** registered using [sqlite3_auto_extension()]. 6043*/ 6044void sqlite3_reset_auto_extension(void); 6045 6046/* 6047** The interface to the virtual-table mechanism is currently considered 6048** to be experimental. The interface might change in incompatible ways. 6049** If this is a problem for you, do not use the interface at this time. 6050** 6051** When the virtual-table mechanism stabilizes, we will declare the 6052** interface fixed, support it indefinitely, and remove this comment. 6053*/ 6054 6055/* 6056** Structures used by the virtual table interface 6057*/ 6058typedef struct sqlite3_vtab sqlite3_vtab; 6059typedef struct sqlite3_index_info sqlite3_index_info; 6060typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6061typedef struct sqlite3_module sqlite3_module; 6062 6063/* 6064** CAPI3REF: Virtual Table Object 6065** KEYWORDS: sqlite3_module {virtual table module} 6066** 6067** This structure, sometimes called a "virtual table module", 6068** defines the implementation of a [virtual tables]. 6069** This structure consists mostly of methods for the module. 6070** 6071** ^A virtual table module is created by filling in a persistent 6072** instance of this structure and passing a pointer to that instance 6073** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6074** ^The registration remains valid until it is replaced by a different 6075** module or until the [database connection] closes. The content 6076** of this structure must not change while it is registered with 6077** any database connection. 6078*/ 6079struct sqlite3_module { 6080 int iVersion; 6081 int (*xCreate)(sqlite3*, void *pAux, 6082 int argc, const char *const*argv, 6083 sqlite3_vtab **ppVTab, char**); 6084 int (*xConnect)(sqlite3*, void *pAux, 6085 int argc, const char *const*argv, 6086 sqlite3_vtab **ppVTab, char**); 6087 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6088 int (*xDisconnect)(sqlite3_vtab *pVTab); 6089 int (*xDestroy)(sqlite3_vtab *pVTab); 6090 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6091 int (*xClose)(sqlite3_vtab_cursor*); 6092 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6093 int argc, sqlite3_value **argv); 6094 int (*xNext)(sqlite3_vtab_cursor*); 6095 int (*xEof)(sqlite3_vtab_cursor*); 6096 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6097 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6098 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6099 int (*xBegin)(sqlite3_vtab *pVTab); 6100 int (*xSync)(sqlite3_vtab *pVTab); 6101 int (*xCommit)(sqlite3_vtab *pVTab); 6102 int (*xRollback)(sqlite3_vtab *pVTab); 6103 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6104 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6105 void **ppArg); 6106 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6107 /* The methods above are in version 1 of the sqlite_module object. Those 6108 ** below are for version 2 and greater. */ 6109 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6110 int (*xRelease)(sqlite3_vtab *pVTab, int); 6111 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6112}; 6113 6114/* 6115** CAPI3REF: Virtual Table Indexing Information 6116** KEYWORDS: sqlite3_index_info 6117** 6118** The sqlite3_index_info structure and its substructures is used as part 6119** of the [virtual table] interface to 6120** pass information into and receive the reply from the [xBestIndex] 6121** method of a [virtual table module]. The fields under **Inputs** are the 6122** inputs to xBestIndex and are read-only. xBestIndex inserts its 6123** results into the **Outputs** fields. 6124** 6125** ^(The aConstraint[] array records WHERE clause constraints of the form: 6126** 6127** <blockquote>column OP expr</blockquote> 6128** 6129** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6130** stored in aConstraint[].op using one of the 6131** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6132** ^(The index of the column is stored in 6133** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6134** expr on the right-hand side can be evaluated (and thus the constraint 6135** is usable) and false if it cannot.)^ 6136** 6137** ^The optimizer automatically inverts terms of the form "expr OP column" 6138** and makes other simplifications to the WHERE clause in an attempt to 6139** get as many WHERE clause terms into the form shown above as possible. 6140** ^The aConstraint[] array only reports WHERE clause terms that are 6141** relevant to the particular virtual table being queried. 6142** 6143** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6144** ^Each term of aOrderBy records a column of the ORDER BY clause. 6145** 6146** The colUsed field indicates which columns of the virtual table may be 6147** required by the current scan. Virtual table columns are numbered from 6148** zero in the order in which they appear within the CREATE TABLE statement 6149** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6150** the corresponding bit is set within the colUsed mask if the column may be 6151** required by SQLite. If the table has at least 64 columns and any column 6152** to the right of the first 63 is required, then bit 63 of colUsed is also 6153** set. In other words, column iCol may be required if the expression 6154** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6155** non-zero. 6156** 6157** The [xBestIndex] method must fill aConstraintUsage[] with information 6158** about what parameters to pass to xFilter. ^If argvIndex>0 then 6159** the right-hand side of the corresponding aConstraint[] is evaluated 6160** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6161** is true, then the constraint is assumed to be fully handled by the 6162** virtual table and is not checked again by SQLite.)^ 6163** 6164** ^The idxNum and idxPtr values are recorded and passed into the 6165** [xFilter] method. 6166** ^[sqlite3_free()] is used to free idxPtr if and only if 6167** needToFreeIdxPtr is true. 6168** 6169** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6170** the correct order to satisfy the ORDER BY clause so that no separate 6171** sorting step is required. 6172** 6173** ^The estimatedCost value is an estimate of the cost of a particular 6174** strategy. A cost of N indicates that the cost of the strategy is similar 6175** to a linear scan of an SQLite table with N rows. A cost of log(N) 6176** indicates that the expense of the operation is similar to that of a 6177** binary search on a unique indexed field of an SQLite table with N rows. 6178** 6179** ^The estimatedRows value is an estimate of the number of rows that 6180** will be returned by the strategy. 6181** 6182** The xBestIndex method may optionally populate the idxFlags field with a 6183** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6184** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6185** assumes that the strategy may visit at most one row. 6186** 6187** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6188** SQLite also assumes that if a call to the xUpdate() method is made as 6189** part of the same statement to delete or update a virtual table row and the 6190** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6191** any database changes. In other words, if the xUpdate() returns 6192** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6193** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6194** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6195** the xUpdate method are automatically rolled back by SQLite. 6196** 6197** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6198** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6199** If a virtual table extension is 6200** used with an SQLite version earlier than 3.8.2, the results of attempting 6201** to read or write the estimatedRows field are undefined (but are likely 6202** to included crashing the application). The estimatedRows field should 6203** therefore only be used if [sqlite3_libversion_number()] returns a 6204** value greater than or equal to 3008002. Similarly, the idxFlags field 6205** was added for [version 3.9.0] ([dateof:3.9.0]). 6206** It may therefore only be used if 6207** sqlite3_libversion_number() returns a value greater than or equal to 6208** 3009000. 6209*/ 6210struct sqlite3_index_info { 6211 /* Inputs */ 6212 int nConstraint; /* Number of entries in aConstraint */ 6213 struct sqlite3_index_constraint { 6214 int iColumn; /* Column constrained. -1 for ROWID */ 6215 unsigned char op; /* Constraint operator */ 6216 unsigned char usable; /* True if this constraint is usable */ 6217 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6218 } *aConstraint; /* Table of WHERE clause constraints */ 6219 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6220 struct sqlite3_index_orderby { 6221 int iColumn; /* Column number */ 6222 unsigned char desc; /* True for DESC. False for ASC. */ 6223 } *aOrderBy; /* The ORDER BY clause */ 6224 /* Outputs */ 6225 struct sqlite3_index_constraint_usage { 6226 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6227 unsigned char omit; /* Do not code a test for this constraint */ 6228 } *aConstraintUsage; 6229 int idxNum; /* Number used to identify the index */ 6230 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6231 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6232 int orderByConsumed; /* True if output is already ordered */ 6233 double estimatedCost; /* Estimated cost of using this index */ 6234 /* Fields below are only available in SQLite 3.8.2 and later */ 6235 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6236 /* Fields below are only available in SQLite 3.9.0 and later */ 6237 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6238 /* Fields below are only available in SQLite 3.10.0 and later */ 6239 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6240}; 6241 6242/* 6243** CAPI3REF: Virtual Table Scan Flags 6244*/ 6245#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6246 6247/* 6248** CAPI3REF: Virtual Table Constraint Operator Codes 6249** 6250** These macros defined the allowed values for the 6251** [sqlite3_index_info].aConstraint[].op field. Each value represents 6252** an operator that is part of a constraint term in the wHERE clause of 6253** a query that uses a [virtual table]. 6254*/ 6255#define SQLITE_INDEX_CONSTRAINT_EQ 2 6256#define SQLITE_INDEX_CONSTRAINT_GT 4 6257#define SQLITE_INDEX_CONSTRAINT_LE 8 6258#define SQLITE_INDEX_CONSTRAINT_LT 16 6259#define SQLITE_INDEX_CONSTRAINT_GE 32 6260#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6261#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6262#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6263#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6264#define SQLITE_INDEX_CONSTRAINT_NE 68 6265#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6266#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6267#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6268#define SQLITE_INDEX_CONSTRAINT_IS 72 6269 6270/* 6271** CAPI3REF: Register A Virtual Table Implementation 6272** METHOD: sqlite3 6273** 6274** ^These routines are used to register a new [virtual table module] name. 6275** ^Module names must be registered before 6276** creating a new [virtual table] using the module and before using a 6277** preexisting [virtual table] for the module. 6278** 6279** ^The module name is registered on the [database connection] specified 6280** by the first parameter. ^The name of the module is given by the 6281** second parameter. ^The third parameter is a pointer to 6282** the implementation of the [virtual table module]. ^The fourth 6283** parameter is an arbitrary client data pointer that is passed through 6284** into the [xCreate] and [xConnect] methods of the virtual table module 6285** when a new virtual table is be being created or reinitialized. 6286** 6287** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6288** is a pointer to a destructor for the pClientData. ^SQLite will 6289** invoke the destructor function (if it is not NULL) when SQLite 6290** no longer needs the pClientData pointer. ^The destructor will also 6291** be invoked if the call to sqlite3_create_module_v2() fails. 6292** ^The sqlite3_create_module() 6293** interface is equivalent to sqlite3_create_module_v2() with a NULL 6294** destructor. 6295*/ 6296int sqlite3_create_module( 6297 sqlite3 *db, /* SQLite connection to register module with */ 6298 const char *zName, /* Name of the module */ 6299 const sqlite3_module *p, /* Methods for the module */ 6300 void *pClientData /* Client data for xCreate/xConnect */ 6301); 6302int sqlite3_create_module_v2( 6303 sqlite3 *db, /* SQLite connection to register module with */ 6304 const char *zName, /* Name of the module */ 6305 const sqlite3_module *p, /* Methods for the module */ 6306 void *pClientData, /* Client data for xCreate/xConnect */ 6307 void(*xDestroy)(void*) /* Module destructor function */ 6308); 6309 6310/* 6311** CAPI3REF: Virtual Table Instance Object 6312** KEYWORDS: sqlite3_vtab 6313** 6314** Every [virtual table module] implementation uses a subclass 6315** of this object to describe a particular instance 6316** of the [virtual table]. Each subclass will 6317** be tailored to the specific needs of the module implementation. 6318** The purpose of this superclass is to define certain fields that are 6319** common to all module implementations. 6320** 6321** ^Virtual tables methods can set an error message by assigning a 6322** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6323** take care that any prior string is freed by a call to [sqlite3_free()] 6324** prior to assigning a new string to zErrMsg. ^After the error message 6325** is delivered up to the client application, the string will be automatically 6326** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6327*/ 6328struct sqlite3_vtab { 6329 const sqlite3_module *pModule; /* The module for this virtual table */ 6330 int nRef; /* Number of open cursors */ 6331 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6332 /* Virtual table implementations will typically add additional fields */ 6333}; 6334 6335/* 6336** CAPI3REF: Virtual Table Cursor Object 6337** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6338** 6339** Every [virtual table module] implementation uses a subclass of the 6340** following structure to describe cursors that point into the 6341** [virtual table] and are used 6342** to loop through the virtual table. Cursors are created using the 6343** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6344** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6345** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6346** of the module. Each module implementation will define 6347** the content of a cursor structure to suit its own needs. 6348** 6349** This superclass exists in order to define fields of the cursor that 6350** are common to all implementations. 6351*/ 6352struct sqlite3_vtab_cursor { 6353 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6354 /* Virtual table implementations will typically add additional fields */ 6355}; 6356 6357/* 6358** CAPI3REF: Declare The Schema Of A Virtual Table 6359** 6360** ^The [xCreate] and [xConnect] methods of a 6361** [virtual table module] call this interface 6362** to declare the format (the names and datatypes of the columns) of 6363** the virtual tables they implement. 6364*/ 6365int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6366 6367/* 6368** CAPI3REF: Overload A Function For A Virtual Table 6369** METHOD: sqlite3 6370** 6371** ^(Virtual tables can provide alternative implementations of functions 6372** using the [xFindFunction] method of the [virtual table module]. 6373** But global versions of those functions 6374** must exist in order to be overloaded.)^ 6375** 6376** ^(This API makes sure a global version of a function with a particular 6377** name and number of parameters exists. If no such function exists 6378** before this API is called, a new function is created.)^ ^The implementation 6379** of the new function always causes an exception to be thrown. So 6380** the new function is not good for anything by itself. Its only 6381** purpose is to be a placeholder function that can be overloaded 6382** by a [virtual table]. 6383*/ 6384int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6385 6386/* 6387** The interface to the virtual-table mechanism defined above (back up 6388** to a comment remarkably similar to this one) is currently considered 6389** to be experimental. The interface might change in incompatible ways. 6390** If this is a problem for you, do not use the interface at this time. 6391** 6392** When the virtual-table mechanism stabilizes, we will declare the 6393** interface fixed, support it indefinitely, and remove this comment. 6394*/ 6395 6396/* 6397** CAPI3REF: A Handle To An Open BLOB 6398** KEYWORDS: {BLOB handle} {BLOB handles} 6399** 6400** An instance of this object represents an open BLOB on which 6401** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6402** ^Objects of this type are created by [sqlite3_blob_open()] 6403** and destroyed by [sqlite3_blob_close()]. 6404** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6405** can be used to read or write small subsections of the BLOB. 6406** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6407*/ 6408typedef struct sqlite3_blob sqlite3_blob; 6409 6410/* 6411** CAPI3REF: Open A BLOB For Incremental I/O 6412** METHOD: sqlite3 6413** CONSTRUCTOR: sqlite3_blob 6414** 6415** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6416** in row iRow, column zColumn, table zTable in database zDb; 6417** in other words, the same BLOB that would be selected by: 6418** 6419** <pre> 6420** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6421** </pre>)^ 6422** 6423** ^(Parameter zDb is not the filename that contains the database, but 6424** rather the symbolic name of the database. For attached databases, this is 6425** the name that appears after the AS keyword in the [ATTACH] statement. 6426** For the main database file, the database name is "main". For TEMP 6427** tables, the database name is "temp".)^ 6428** 6429** ^If the flags parameter is non-zero, then the BLOB is opened for read 6430** and write access. ^If the flags parameter is zero, the BLOB is opened for 6431** read-only access. 6432** 6433** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6434** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6435** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6436** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6437** on *ppBlob after this function it returns. 6438** 6439** This function fails with SQLITE_ERROR if any of the following are true: 6440** <ul> 6441** <li> ^(Database zDb does not exist)^, 6442** <li> ^(Table zTable does not exist within database zDb)^, 6443** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6444** <li> ^(Column zColumn does not exist)^, 6445** <li> ^(Row iRow is not present in the table)^, 6446** <li> ^(The specified column of row iRow contains a value that is not 6447** a TEXT or BLOB value)^, 6448** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6449** constraint and the blob is being opened for read/write access)^, 6450** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6451** column zColumn is part of a [child key] definition and the blob is 6452** being opened for read/write access)^. 6453** </ul> 6454** 6455** ^Unless it returns SQLITE_MISUSE, this function sets the 6456** [database connection] error code and message accessible via 6457** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6458** 6459** A BLOB referenced by sqlite3_blob_open() may be read using the 6460** [sqlite3_blob_read()] interface and modified by using 6461** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6462** different row of the same table using the [sqlite3_blob_reopen()] 6463** interface. However, the column, table, or database of a [BLOB handle] 6464** cannot be changed after the [BLOB handle] is opened. 6465** 6466** ^(If the row that a BLOB handle points to is modified by an 6467** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6468** then the BLOB handle is marked as "expired". 6469** This is true if any column of the row is changed, even a column 6470** other than the one the BLOB handle is open on.)^ 6471** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6472** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6473** ^(Changes written into a BLOB prior to the BLOB expiring are not 6474** rolled back by the expiration of the BLOB. Such changes will eventually 6475** commit if the transaction continues to completion.)^ 6476** 6477** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6478** the opened blob. ^The size of a blob may not be changed by this 6479** interface. Use the [UPDATE] SQL command to change the size of a 6480** blob. 6481** 6482** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6483** and the built-in [zeroblob] SQL function may be used to create a 6484** zero-filled blob to read or write using the incremental-blob interface. 6485** 6486** To avoid a resource leak, every open [BLOB handle] should eventually 6487** be released by a call to [sqlite3_blob_close()]. 6488** 6489** See also: [sqlite3_blob_close()], 6490** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6491** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6492*/ 6493int sqlite3_blob_open( 6494 sqlite3*, 6495 const char *zDb, 6496 const char *zTable, 6497 const char *zColumn, 6498 sqlite3_int64 iRow, 6499 int flags, 6500 sqlite3_blob **ppBlob 6501); 6502 6503/* 6504** CAPI3REF: Move a BLOB Handle to a New Row 6505** METHOD: sqlite3_blob 6506** 6507** ^This function is used to move an existing [BLOB handle] so that it points 6508** to a different row of the same database table. ^The new row is identified 6509** by the rowid value passed as the second argument. Only the row can be 6510** changed. ^The database, table and column on which the blob handle is open 6511** remain the same. Moving an existing [BLOB handle] to a new row is 6512** faster than closing the existing handle and opening a new one. 6513** 6514** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6515** it must exist and there must be either a blob or text value stored in 6516** the nominated column.)^ ^If the new row is not present in the table, or if 6517** it does not contain a blob or text value, or if another error occurs, an 6518** SQLite error code is returned and the blob handle is considered aborted. 6519** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6520** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6521** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6522** always returns zero. 6523** 6524** ^This function sets the database handle error code and message. 6525*/ 6526int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6527 6528/* 6529** CAPI3REF: Close A BLOB Handle 6530** DESTRUCTOR: sqlite3_blob 6531** 6532** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6533** unconditionally. Even if this routine returns an error code, the 6534** handle is still closed.)^ 6535** 6536** ^If the blob handle being closed was opened for read-write access, and if 6537** the database is in auto-commit mode and there are no other open read-write 6538** blob handles or active write statements, the current transaction is 6539** committed. ^If an error occurs while committing the transaction, an error 6540** code is returned and the transaction rolled back. 6541** 6542** Calling this function with an argument that is not a NULL pointer or an 6543** open blob handle results in undefined behaviour. ^Calling this routine 6544** with a null pointer (such as would be returned by a failed call to 6545** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6546** is passed a valid open blob handle, the values returned by the 6547** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6548*/ 6549int sqlite3_blob_close(sqlite3_blob *); 6550 6551/* 6552** CAPI3REF: Return The Size Of An Open BLOB 6553** METHOD: sqlite3_blob 6554** 6555** ^Returns the size in bytes of the BLOB accessible via the 6556** successfully opened [BLOB handle] in its only argument. ^The 6557** incremental blob I/O routines can only read or overwriting existing 6558** blob content; they cannot change the size of a blob. 6559** 6560** This routine only works on a [BLOB handle] which has been created 6561** by a prior successful call to [sqlite3_blob_open()] and which has not 6562** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6563** to this routine results in undefined and probably undesirable behavior. 6564*/ 6565int sqlite3_blob_bytes(sqlite3_blob *); 6566 6567/* 6568** CAPI3REF: Read Data From A BLOB Incrementally 6569** METHOD: sqlite3_blob 6570** 6571** ^(This function is used to read data from an open [BLOB handle] into a 6572** caller-supplied buffer. N bytes of data are copied into buffer Z 6573** from the open BLOB, starting at offset iOffset.)^ 6574** 6575** ^If offset iOffset is less than N bytes from the end of the BLOB, 6576** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6577** less than zero, [SQLITE_ERROR] is returned and no data is read. 6578** ^The size of the blob (and hence the maximum value of N+iOffset) 6579** can be determined using the [sqlite3_blob_bytes()] interface. 6580** 6581** ^An attempt to read from an expired [BLOB handle] fails with an 6582** error code of [SQLITE_ABORT]. 6583** 6584** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6585** Otherwise, an [error code] or an [extended error code] is returned.)^ 6586** 6587** This routine only works on a [BLOB handle] which has been created 6588** by a prior successful call to [sqlite3_blob_open()] and which has not 6589** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6590** to this routine results in undefined and probably undesirable behavior. 6591** 6592** See also: [sqlite3_blob_write()]. 6593*/ 6594int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6595 6596/* 6597** CAPI3REF: Write Data Into A BLOB Incrementally 6598** METHOD: sqlite3_blob 6599** 6600** ^(This function is used to write data into an open [BLOB handle] from a 6601** caller-supplied buffer. N bytes of data are copied from the buffer Z 6602** into the open BLOB, starting at offset iOffset.)^ 6603** 6604** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6605** Otherwise, an [error code] or an [extended error code] is returned.)^ 6606** ^Unless SQLITE_MISUSE is returned, this function sets the 6607** [database connection] error code and message accessible via 6608** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6609** 6610** ^If the [BLOB handle] passed as the first argument was not opened for 6611** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6612** this function returns [SQLITE_READONLY]. 6613** 6614** This function may only modify the contents of the BLOB; it is 6615** not possible to increase the size of a BLOB using this API. 6616** ^If offset iOffset is less than N bytes from the end of the BLOB, 6617** [SQLITE_ERROR] is returned and no data is written. The size of the 6618** BLOB (and hence the maximum value of N+iOffset) can be determined 6619** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6620** than zero [SQLITE_ERROR] is returned and no data is written. 6621** 6622** ^An attempt to write to an expired [BLOB handle] fails with an 6623** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6624** before the [BLOB handle] expired are not rolled back by the 6625** expiration of the handle, though of course those changes might 6626** have been overwritten by the statement that expired the BLOB handle 6627** or by other independent statements. 6628** 6629** This routine only works on a [BLOB handle] which has been created 6630** by a prior successful call to [sqlite3_blob_open()] and which has not 6631** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6632** to this routine results in undefined and probably undesirable behavior. 6633** 6634** See also: [sqlite3_blob_read()]. 6635*/ 6636int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6637 6638/* 6639** CAPI3REF: Virtual File System Objects 6640** 6641** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6642** that SQLite uses to interact 6643** with the underlying operating system. Most SQLite builds come with a 6644** single default VFS that is appropriate for the host computer. 6645** New VFSes can be registered and existing VFSes can be unregistered. 6646** The following interfaces are provided. 6647** 6648** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6649** ^Names are case sensitive. 6650** ^Names are zero-terminated UTF-8 strings. 6651** ^If there is no match, a NULL pointer is returned. 6652** ^If zVfsName is NULL then the default VFS is returned. 6653** 6654** ^New VFSes are registered with sqlite3_vfs_register(). 6655** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6656** ^The same VFS can be registered multiple times without injury. 6657** ^To make an existing VFS into the default VFS, register it again 6658** with the makeDflt flag set. If two different VFSes with the 6659** same name are registered, the behavior is undefined. If a 6660** VFS is registered with a name that is NULL or an empty string, 6661** then the behavior is undefined. 6662** 6663** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6664** ^(If the default VFS is unregistered, another VFS is chosen as 6665** the default. The choice for the new VFS is arbitrary.)^ 6666*/ 6667sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6668int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6669int sqlite3_vfs_unregister(sqlite3_vfs*); 6670 6671/* 6672** CAPI3REF: Mutexes 6673** 6674** The SQLite core uses these routines for thread 6675** synchronization. Though they are intended for internal 6676** use by SQLite, code that links against SQLite is 6677** permitted to use any of these routines. 6678** 6679** The SQLite source code contains multiple implementations 6680** of these mutex routines. An appropriate implementation 6681** is selected automatically at compile-time. The following 6682** implementations are available in the SQLite core: 6683** 6684** <ul> 6685** <li> SQLITE_MUTEX_PTHREADS 6686** <li> SQLITE_MUTEX_W32 6687** <li> SQLITE_MUTEX_NOOP 6688** </ul> 6689** 6690** The SQLITE_MUTEX_NOOP implementation is a set of routines 6691** that does no real locking and is appropriate for use in 6692** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6693** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6694** and Windows. 6695** 6696** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6697** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6698** implementation is included with the library. In this case the 6699** application must supply a custom mutex implementation using the 6700** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6701** before calling sqlite3_initialize() or any other public sqlite3_ 6702** function that calls sqlite3_initialize(). 6703** 6704** ^The sqlite3_mutex_alloc() routine allocates a new 6705** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6706** routine returns NULL if it is unable to allocate the requested 6707** mutex. The argument to sqlite3_mutex_alloc() must one of these 6708** integer constants: 6709** 6710** <ul> 6711** <li> SQLITE_MUTEX_FAST 6712** <li> SQLITE_MUTEX_RECURSIVE 6713** <li> SQLITE_MUTEX_STATIC_MASTER 6714** <li> SQLITE_MUTEX_STATIC_MEM 6715** <li> SQLITE_MUTEX_STATIC_OPEN 6716** <li> SQLITE_MUTEX_STATIC_PRNG 6717** <li> SQLITE_MUTEX_STATIC_LRU 6718** <li> SQLITE_MUTEX_STATIC_PMEM 6719** <li> SQLITE_MUTEX_STATIC_APP1 6720** <li> SQLITE_MUTEX_STATIC_APP2 6721** <li> SQLITE_MUTEX_STATIC_APP3 6722** <li> SQLITE_MUTEX_STATIC_VFS1 6723** <li> SQLITE_MUTEX_STATIC_VFS2 6724** <li> SQLITE_MUTEX_STATIC_VFS3 6725** </ul> 6726** 6727** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6728** cause sqlite3_mutex_alloc() to create 6729** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6730** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6731** The mutex implementation does not need to make a distinction 6732** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6733** not want to. SQLite will only request a recursive mutex in 6734** cases where it really needs one. If a faster non-recursive mutex 6735** implementation is available on the host platform, the mutex subsystem 6736** might return such a mutex in response to SQLITE_MUTEX_FAST. 6737** 6738** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6739** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6740** a pointer to a static preexisting mutex. ^Nine static mutexes are 6741** used by the current version of SQLite. Future versions of SQLite 6742** may add additional static mutexes. Static mutexes are for internal 6743** use by SQLite only. Applications that use SQLite mutexes should 6744** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6745** SQLITE_MUTEX_RECURSIVE. 6746** 6747** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6748** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6749** returns a different mutex on every call. ^For the static 6750** mutex types, the same mutex is returned on every call that has 6751** the same type number. 6752** 6753** ^The sqlite3_mutex_free() routine deallocates a previously 6754** allocated dynamic mutex. Attempting to deallocate a static 6755** mutex results in undefined behavior. 6756** 6757** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6758** to enter a mutex. ^If another thread is already within the mutex, 6759** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6760** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6761** upon successful entry. ^(Mutexes created using 6762** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6763** In such cases, the 6764** mutex must be exited an equal number of times before another thread 6765** can enter.)^ If the same thread tries to enter any mutex other 6766** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6767** 6768** ^(Some systems (for example, Windows 95) do not support the operation 6769** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6770** will always return SQLITE_BUSY. The SQLite core only ever uses 6771** sqlite3_mutex_try() as an optimization so this is acceptable 6772** behavior.)^ 6773** 6774** ^The sqlite3_mutex_leave() routine exits a mutex that was 6775** previously entered by the same thread. The behavior 6776** is undefined if the mutex is not currently entered by the 6777** calling thread or is not currently allocated. 6778** 6779** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6780** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6781** behave as no-ops. 6782** 6783** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6784*/ 6785sqlite3_mutex *sqlite3_mutex_alloc(int); 6786void sqlite3_mutex_free(sqlite3_mutex*); 6787void sqlite3_mutex_enter(sqlite3_mutex*); 6788int sqlite3_mutex_try(sqlite3_mutex*); 6789void sqlite3_mutex_leave(sqlite3_mutex*); 6790 6791/* 6792** CAPI3REF: Mutex Methods Object 6793** 6794** An instance of this structure defines the low-level routines 6795** used to allocate and use mutexes. 6796** 6797** Usually, the default mutex implementations provided by SQLite are 6798** sufficient, however the application has the option of substituting a custom 6799** implementation for specialized deployments or systems for which SQLite 6800** does not provide a suitable implementation. In this case, the application 6801** creates and populates an instance of this structure to pass 6802** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6803** Additionally, an instance of this structure can be used as an 6804** output variable when querying the system for the current mutex 6805** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6806** 6807** ^The xMutexInit method defined by this structure is invoked as 6808** part of system initialization by the sqlite3_initialize() function. 6809** ^The xMutexInit routine is called by SQLite exactly once for each 6810** effective call to [sqlite3_initialize()]. 6811** 6812** ^The xMutexEnd method defined by this structure is invoked as 6813** part of system shutdown by the sqlite3_shutdown() function. The 6814** implementation of this method is expected to release all outstanding 6815** resources obtained by the mutex methods implementation, especially 6816** those obtained by the xMutexInit method. ^The xMutexEnd() 6817** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6818** 6819** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6820** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6821** xMutexNotheld) implement the following interfaces (respectively): 6822** 6823** <ul> 6824** <li> [sqlite3_mutex_alloc()] </li> 6825** <li> [sqlite3_mutex_free()] </li> 6826** <li> [sqlite3_mutex_enter()] </li> 6827** <li> [sqlite3_mutex_try()] </li> 6828** <li> [sqlite3_mutex_leave()] </li> 6829** <li> [sqlite3_mutex_held()] </li> 6830** <li> [sqlite3_mutex_notheld()] </li> 6831** </ul>)^ 6832** 6833** The only difference is that the public sqlite3_XXX functions enumerated 6834** above silently ignore any invocations that pass a NULL pointer instead 6835** of a valid mutex handle. The implementations of the methods defined 6836** by this structure are not required to handle this case, the results 6837** of passing a NULL pointer instead of a valid mutex handle are undefined 6838** (i.e. it is acceptable to provide an implementation that segfaults if 6839** it is passed a NULL pointer). 6840** 6841** The xMutexInit() method must be threadsafe. It must be harmless to 6842** invoke xMutexInit() multiple times within the same process and without 6843** intervening calls to xMutexEnd(). Second and subsequent calls to 6844** xMutexInit() must be no-ops. 6845** 6846** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6847** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6848** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6849** memory allocation for a fast or recursive mutex. 6850** 6851** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6852** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6853** If xMutexInit fails in any way, it is expected to clean up after itself 6854** prior to returning. 6855*/ 6856typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6857struct sqlite3_mutex_methods { 6858 int (*xMutexInit)(void); 6859 int (*xMutexEnd)(void); 6860 sqlite3_mutex *(*xMutexAlloc)(int); 6861 void (*xMutexFree)(sqlite3_mutex *); 6862 void (*xMutexEnter)(sqlite3_mutex *); 6863 int (*xMutexTry)(sqlite3_mutex *); 6864 void (*xMutexLeave)(sqlite3_mutex *); 6865 int (*xMutexHeld)(sqlite3_mutex *); 6866 int (*xMutexNotheld)(sqlite3_mutex *); 6867}; 6868 6869/* 6870** CAPI3REF: Mutex Verification Routines 6871** 6872** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6873** are intended for use inside assert() statements. The SQLite core 6874** never uses these routines except inside an assert() and applications 6875** are advised to follow the lead of the core. The SQLite core only 6876** provides implementations for these routines when it is compiled 6877** with the SQLITE_DEBUG flag. External mutex implementations 6878** are only required to provide these routines if SQLITE_DEBUG is 6879** defined and if NDEBUG is not defined. 6880** 6881** These routines should return true if the mutex in their argument 6882** is held or not held, respectively, by the calling thread. 6883** 6884** The implementation is not required to provide versions of these 6885** routines that actually work. If the implementation does not provide working 6886** versions of these routines, it should at least provide stubs that always 6887** return true so that one does not get spurious assertion failures. 6888** 6889** If the argument to sqlite3_mutex_held() is a NULL pointer then 6890** the routine should return 1. This seems counter-intuitive since 6891** clearly the mutex cannot be held if it does not exist. But 6892** the reason the mutex does not exist is because the build is not 6893** using mutexes. And we do not want the assert() containing the 6894** call to sqlite3_mutex_held() to fail, so a non-zero return is 6895** the appropriate thing to do. The sqlite3_mutex_notheld() 6896** interface should also return 1 when given a NULL pointer. 6897*/ 6898#ifndef NDEBUG 6899int sqlite3_mutex_held(sqlite3_mutex*); 6900int sqlite3_mutex_notheld(sqlite3_mutex*); 6901#endif 6902 6903/* 6904** CAPI3REF: Mutex Types 6905** 6906** The [sqlite3_mutex_alloc()] interface takes a single argument 6907** which is one of these integer constants. 6908** 6909** The set of static mutexes may change from one SQLite release to the 6910** next. Applications that override the built-in mutex logic must be 6911** prepared to accommodate additional static mutexes. 6912*/ 6913#define SQLITE_MUTEX_FAST 0 6914#define SQLITE_MUTEX_RECURSIVE 1 6915#define SQLITE_MUTEX_STATIC_MASTER 2 6916#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6917#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6918#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6919#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6920#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6921#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6922#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6923#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6924#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6925#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6926#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6927#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6928#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6929 6930/* 6931** CAPI3REF: Retrieve the mutex for a database connection 6932** METHOD: sqlite3 6933** 6934** ^This interface returns a pointer the [sqlite3_mutex] object that 6935** serializes access to the [database connection] given in the argument 6936** when the [threading mode] is Serialized. 6937** ^If the [threading mode] is Single-thread or Multi-thread then this 6938** routine returns a NULL pointer. 6939*/ 6940sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6941 6942/* 6943** CAPI3REF: Low-Level Control Of Database Files 6944** METHOD: sqlite3 6945** 6946** ^The [sqlite3_file_control()] interface makes a direct call to the 6947** xFileControl method for the [sqlite3_io_methods] object associated 6948** with a particular database identified by the second argument. ^The 6949** name of the database is "main" for the main database or "temp" for the 6950** TEMP database, or the name that appears after the AS keyword for 6951** databases that are added using the [ATTACH] SQL command. 6952** ^A NULL pointer can be used in place of "main" to refer to the 6953** main database file. 6954** ^The third and fourth parameters to this routine 6955** are passed directly through to the second and third parameters of 6956** the xFileControl method. ^The return value of the xFileControl 6957** method becomes the return value of this routine. 6958** 6959** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 6960** a pointer to the underlying [sqlite3_file] object to be written into 6961** the space pointed to by the 4th parameter. ^The [SQLITE_FCNTL_FILE_POINTER] 6962** case is a short-circuit path which does not actually invoke the 6963** underlying sqlite3_io_methods.xFileControl method. 6964** 6965** ^If the second parameter (zDbName) does not match the name of any 6966** open database file, then SQLITE_ERROR is returned. ^This error 6967** code is not remembered and will not be recalled by [sqlite3_errcode()] 6968** or [sqlite3_errmsg()]. The underlying xFileControl method might 6969** also return SQLITE_ERROR. There is no way to distinguish between 6970** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6971** xFileControl method. 6972** 6973** See also: [file control opcodes] 6974*/ 6975int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6976 6977/* 6978** CAPI3REF: Testing Interface 6979** 6980** ^The sqlite3_test_control() interface is used to read out internal 6981** state of SQLite and to inject faults into SQLite for testing 6982** purposes. ^The first parameter is an operation code that determines 6983** the number, meaning, and operation of all subsequent parameters. 6984** 6985** This interface is not for use by applications. It exists solely 6986** for verifying the correct operation of the SQLite library. Depending 6987** on how the SQLite library is compiled, this interface might not exist. 6988** 6989** The details of the operation codes, their meanings, the parameters 6990** they take, and what they do are all subject to change without notice. 6991** Unlike most of the SQLite API, this function is not guaranteed to 6992** operate consistently from one release to the next. 6993*/ 6994int sqlite3_test_control(int op, ...); 6995 6996/* 6997** CAPI3REF: Testing Interface Operation Codes 6998** 6999** These constants are the valid operation code parameters used 7000** as the first argument to [sqlite3_test_control()]. 7001** 7002** These parameters and their meanings are subject to change 7003** without notice. These values are for testing purposes only. 7004** Applications should not use any of these parameters or the 7005** [sqlite3_test_control()] interface. 7006*/ 7007#define SQLITE_TESTCTRL_FIRST 5 7008#define SQLITE_TESTCTRL_PRNG_SAVE 5 7009#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7010#define SQLITE_TESTCTRL_PRNG_RESET 7 7011#define SQLITE_TESTCTRL_BITVEC_TEST 8 7012#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7013#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7014#define SQLITE_TESTCTRL_PENDING_BYTE 11 7015#define SQLITE_TESTCTRL_ASSERT 12 7016#define SQLITE_TESTCTRL_ALWAYS 13 7017#define SQLITE_TESTCTRL_RESERVE 14 7018#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7019#define SQLITE_TESTCTRL_ISKEYWORD 16 7020#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7021#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7022#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7023#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7024#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7025#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7026#define SQLITE_TESTCTRL_BYTEORDER 22 7027#define SQLITE_TESTCTRL_ISINIT 23 7028#define SQLITE_TESTCTRL_SORTER_MMAP 24 7029#define SQLITE_TESTCTRL_IMPOSTER 25 7030#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7031#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */ 7032 7033/* 7034** CAPI3REF: SQLite Runtime Status 7035** 7036** ^These interfaces are used to retrieve runtime status information 7037** about the performance of SQLite, and optionally to reset various 7038** highwater marks. ^The first argument is an integer code for 7039** the specific parameter to measure. ^(Recognized integer codes 7040** are of the form [status parameters | SQLITE_STATUS_...].)^ 7041** ^The current value of the parameter is returned into *pCurrent. 7042** ^The highest recorded value is returned in *pHighwater. ^If the 7043** resetFlag is true, then the highest record value is reset after 7044** *pHighwater is written. ^(Some parameters do not record the highest 7045** value. For those parameters 7046** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7047** ^(Other parameters record only the highwater mark and not the current 7048** value. For these latter parameters nothing is written into *pCurrent.)^ 7049** 7050** ^The sqlite3_status() and sqlite3_status64() routines return 7051** SQLITE_OK on success and a non-zero [error code] on failure. 7052** 7053** If either the current value or the highwater mark is too large to 7054** be represented by a 32-bit integer, then the values returned by 7055** sqlite3_status() are undefined. 7056** 7057** See also: [sqlite3_db_status()] 7058*/ 7059int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7060int sqlite3_status64( 7061 int op, 7062 sqlite3_int64 *pCurrent, 7063 sqlite3_int64 *pHighwater, 7064 int resetFlag 7065); 7066 7067 7068/* 7069** CAPI3REF: Status Parameters 7070** KEYWORDS: {status parameters} 7071** 7072** These integer constants designate various run-time status parameters 7073** that can be returned by [sqlite3_status()]. 7074** 7075** <dl> 7076** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7077** <dd>This parameter is the current amount of memory checked out 7078** using [sqlite3_malloc()], either directly or indirectly. The 7079** figure includes calls made to [sqlite3_malloc()] by the application 7080** and internal memory usage by the SQLite library. Auxiliary page-cache 7081** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7082** this parameter. The amount returned is the sum of the allocation 7083** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7084** 7085** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7086** <dd>This parameter records the largest memory allocation request 7087** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7088** internal equivalents). Only the value returned in the 7089** *pHighwater parameter to [sqlite3_status()] is of interest. 7090** The value written into the *pCurrent parameter is undefined.</dd>)^ 7091** 7092** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7093** <dd>This parameter records the number of separate memory allocations 7094** currently checked out.</dd>)^ 7095** 7096** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7097** <dd>This parameter returns the number of pages used out of the 7098** [pagecache memory allocator] that was configured using 7099** [SQLITE_CONFIG_PAGECACHE]. The 7100** value returned is in pages, not in bytes.</dd>)^ 7101** 7102** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7103** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7104** <dd>This parameter returns the number of bytes of page cache 7105** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7106** buffer and where forced to overflow to [sqlite3_malloc()]. The 7107** returned value includes allocations that overflowed because they 7108** where too large (they were larger than the "sz" parameter to 7109** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7110** no space was left in the page cache.</dd>)^ 7111** 7112** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7113** <dd>This parameter records the largest memory allocation request 7114** handed to [pagecache memory allocator]. Only the value returned in the 7115** *pHighwater parameter to [sqlite3_status()] is of interest. 7116** The value written into the *pCurrent parameter is undefined.</dd>)^ 7117** 7118** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7119** <dd>No longer used.</dd> 7120** 7121** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7122** <dd>No longer used.</dd> 7123** 7124** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7125** <dd>No longer used.</dd> 7126** 7127** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7128** <dd>The *pHighwater parameter records the deepest parser stack. 7129** The *pCurrent value is undefined. The *pHighwater value is only 7130** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7131** </dl> 7132** 7133** New status parameters may be added from time to time. 7134*/ 7135#define SQLITE_STATUS_MEMORY_USED 0 7136#define SQLITE_STATUS_PAGECACHE_USED 1 7137#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7138#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7139#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7140#define SQLITE_STATUS_MALLOC_SIZE 5 7141#define SQLITE_STATUS_PARSER_STACK 6 7142#define SQLITE_STATUS_PAGECACHE_SIZE 7 7143#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7144#define SQLITE_STATUS_MALLOC_COUNT 9 7145 7146/* 7147** CAPI3REF: Database Connection Status 7148** METHOD: sqlite3 7149** 7150** ^This interface is used to retrieve runtime status information 7151** about a single [database connection]. ^The first argument is the 7152** database connection object to be interrogated. ^The second argument 7153** is an integer constant, taken from the set of 7154** [SQLITE_DBSTATUS options], that 7155** determines the parameter to interrogate. The set of 7156** [SQLITE_DBSTATUS options] is likely 7157** to grow in future releases of SQLite. 7158** 7159** ^The current value of the requested parameter is written into *pCur 7160** and the highest instantaneous value is written into *pHiwtr. ^If 7161** the resetFlg is true, then the highest instantaneous value is 7162** reset back down to the current value. 7163** 7164** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7165** non-zero [error code] on failure. 7166** 7167** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7168*/ 7169int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7170 7171/* 7172** CAPI3REF: Status Parameters for database connections 7173** KEYWORDS: {SQLITE_DBSTATUS options} 7174** 7175** These constants are the available integer "verbs" that can be passed as 7176** the second argument to the [sqlite3_db_status()] interface. 7177** 7178** New verbs may be added in future releases of SQLite. Existing verbs 7179** might be discontinued. Applications should check the return code from 7180** [sqlite3_db_status()] to make sure that the call worked. 7181** The [sqlite3_db_status()] interface will return a non-zero error code 7182** if a discontinued or unsupported verb is invoked. 7183** 7184** <dl> 7185** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7186** <dd>This parameter returns the number of lookaside memory slots currently 7187** checked out.</dd>)^ 7188** 7189** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7190** <dd>This parameter returns the number malloc attempts that were 7191** satisfied using lookaside memory. Only the high-water value is meaningful; 7192** the current value is always zero.)^ 7193** 7194** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7195** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7196** <dd>This parameter returns the number malloc attempts that might have 7197** been satisfied using lookaside memory but failed due to the amount of 7198** memory requested being larger than the lookaside slot size. 7199** Only the high-water value is meaningful; 7200** the current value is always zero.)^ 7201** 7202** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7203** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7204** <dd>This parameter returns the number malloc attempts that might have 7205** been satisfied using lookaside memory but failed due to all lookaside 7206** memory already being in use. 7207** Only the high-water value is meaningful; 7208** the current value is always zero.)^ 7209** 7210** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7211** <dd>This parameter returns the approximate number of bytes of heap 7212** memory used by all pager caches associated with the database connection.)^ 7213** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7214** 7215** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7216** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7217** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7218** pager cache is shared between two or more connections the bytes of heap 7219** memory used by that pager cache is divided evenly between the attached 7220** connections.)^ In other words, if none of the pager caches associated 7221** with the database connection are shared, this request returns the same 7222** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7223** shared, the value returned by this call will be smaller than that returned 7224** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7225** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7226** 7227** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7228** <dd>This parameter returns the approximate number of bytes of heap 7229** memory used to store the schema for all databases associated 7230** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7231** ^The full amount of memory used by the schemas is reported, even if the 7232** schema memory is shared with other database connections due to 7233** [shared cache mode] being enabled. 7234** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7235** 7236** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7237** <dd>This parameter returns the approximate number of bytes of heap 7238** and lookaside memory used by all prepared statements associated with 7239** the database connection.)^ 7240** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7241** </dd> 7242** 7243** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7244** <dd>This parameter returns the number of pager cache hits that have 7245** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7246** is always 0. 7247** </dd> 7248** 7249** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7250** <dd>This parameter returns the number of pager cache misses that have 7251** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7252** is always 0. 7253** </dd> 7254** 7255** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7256** <dd>This parameter returns the number of dirty cache entries that have 7257** been written to disk. Specifically, the number of pages written to the 7258** wal file in wal mode databases, or the number of pages written to the 7259** database file in rollback mode databases. Any pages written as part of 7260** transaction rollback or database recovery operations are not included. 7261** If an IO or other error occurs while writing a page to disk, the effect 7262** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7263** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7264** </dd> 7265** 7266** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 7267** <dd>This parameter returns the number of dirty cache entries that have 7268** been written to disk in the middle of a transaction due to the page 7269** cache overflowing. Transactions are more efficient if they are written 7270** to disk all at once. When pages spill mid-transaction, that introduces 7271** additional overhead. This parameter can be used help identify 7272** inefficiencies that can be resolve by increasing the cache size. 7273** </dd> 7274** 7275** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7276** <dd>This parameter returns zero for the current value if and only if 7277** all foreign key constraints (deferred or immediate) have been 7278** resolved.)^ ^The highwater mark is always 0. 7279** </dd> 7280** </dl> 7281*/ 7282#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7283#define SQLITE_DBSTATUS_CACHE_USED 1 7284#define SQLITE_DBSTATUS_SCHEMA_USED 2 7285#define SQLITE_DBSTATUS_STMT_USED 3 7286#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7287#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7288#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7289#define SQLITE_DBSTATUS_CACHE_HIT 7 7290#define SQLITE_DBSTATUS_CACHE_MISS 8 7291#define SQLITE_DBSTATUS_CACHE_WRITE 9 7292#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7293#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7294#define SQLITE_DBSTATUS_CACHE_SPILL 12 7295#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 7296 7297 7298/* 7299** CAPI3REF: Prepared Statement Status 7300** METHOD: sqlite3_stmt 7301** 7302** ^(Each prepared statement maintains various 7303** [SQLITE_STMTSTATUS counters] that measure the number 7304** of times it has performed specific operations.)^ These counters can 7305** be used to monitor the performance characteristics of the prepared 7306** statements. For example, if the number of table steps greatly exceeds 7307** the number of table searches or result rows, that would tend to indicate 7308** that the prepared statement is using a full table scan rather than 7309** an index. 7310** 7311** ^(This interface is used to retrieve and reset counter values from 7312** a [prepared statement]. The first argument is the prepared statement 7313** object to be interrogated. The second argument 7314** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7315** to be interrogated.)^ 7316** ^The current value of the requested counter is returned. 7317** ^If the resetFlg is true, then the counter is reset to zero after this 7318** interface call returns. 7319** 7320** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7321*/ 7322int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7323 7324/* 7325** CAPI3REF: Status Parameters for prepared statements 7326** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7327** 7328** These preprocessor macros define integer codes that name counter 7329** values associated with the [sqlite3_stmt_status()] interface. 7330** The meanings of the various counters are as follows: 7331** 7332** <dl> 7333** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7334** <dd>^This is the number of times that SQLite has stepped forward in 7335** a table as part of a full table scan. Large numbers for this counter 7336** may indicate opportunities for performance improvement through 7337** careful use of indices.</dd> 7338** 7339** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7340** <dd>^This is the number of sort operations that have occurred. 7341** A non-zero value in this counter may indicate an opportunity to 7342** improvement performance through careful use of indices.</dd> 7343** 7344** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7345** <dd>^This is the number of rows inserted into transient indices that 7346** were created automatically in order to help joins run faster. 7347** A non-zero value in this counter may indicate an opportunity to 7348** improvement performance by adding permanent indices that do not 7349** need to be reinitialized each time the statement is run.</dd> 7350** 7351** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7352** <dd>^This is the number of virtual machine operations executed 7353** by the prepared statement if that number is less than or equal 7354** to 2147483647. The number of virtual machine operations can be 7355** used as a proxy for the total work done by the prepared statement. 7356** If the number of virtual machine operations exceeds 2147483647 7357** then the value returned by this statement status code is undefined. 7358** 7359** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7360** <dd>^This is the number of times that the prepare statement has been 7361** automatically regenerated due to schema changes or change to 7362** [bound parameters] that might affect the query plan. 7363** 7364** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7365** <dd>^This is the number of times that the prepared statement has 7366** been run. A single "run" for the purposes of this counter is one 7367** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7368** The counter is incremented on the first [sqlite3_step()] call of each 7369** cycle. 7370** 7371** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7372** <dd>^This is the approximate number of bytes of heap memory 7373** used to store the prepared statement. ^This value is not actually 7374** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7375** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7376** </dd> 7377** </dl> 7378*/ 7379#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7380#define SQLITE_STMTSTATUS_SORT 2 7381#define SQLITE_STMTSTATUS_AUTOINDEX 3 7382#define SQLITE_STMTSTATUS_VM_STEP 4 7383#define SQLITE_STMTSTATUS_REPREPARE 5 7384#define SQLITE_STMTSTATUS_RUN 6 7385#define SQLITE_STMTSTATUS_MEMUSED 99 7386 7387/* 7388** CAPI3REF: Custom Page Cache Object 7389** 7390** The sqlite3_pcache type is opaque. It is implemented by 7391** the pluggable module. The SQLite core has no knowledge of 7392** its size or internal structure and never deals with the 7393** sqlite3_pcache object except by holding and passing pointers 7394** to the object. 7395** 7396** See [sqlite3_pcache_methods2] for additional information. 7397*/ 7398typedef struct sqlite3_pcache sqlite3_pcache; 7399 7400/* 7401** CAPI3REF: Custom Page Cache Object 7402** 7403** The sqlite3_pcache_page object represents a single page in the 7404** page cache. The page cache will allocate instances of this 7405** object. Various methods of the page cache use pointers to instances 7406** of this object as parameters or as their return value. 7407** 7408** See [sqlite3_pcache_methods2] for additional information. 7409*/ 7410typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7411struct sqlite3_pcache_page { 7412 void *pBuf; /* The content of the page */ 7413 void *pExtra; /* Extra information associated with the page */ 7414}; 7415 7416/* 7417** CAPI3REF: Application Defined Page Cache. 7418** KEYWORDS: {page cache} 7419** 7420** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7421** register an alternative page cache implementation by passing in an 7422** instance of the sqlite3_pcache_methods2 structure.)^ 7423** In many applications, most of the heap memory allocated by 7424** SQLite is used for the page cache. 7425** By implementing a 7426** custom page cache using this API, an application can better control 7427** the amount of memory consumed by SQLite, the way in which 7428** that memory is allocated and released, and the policies used to 7429** determine exactly which parts of a database file are cached and for 7430** how long. 7431** 7432** The alternative page cache mechanism is an 7433** extreme measure that is only needed by the most demanding applications. 7434** The built-in page cache is recommended for most uses. 7435** 7436** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7437** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7438** the application may discard the parameter after the call to 7439** [sqlite3_config()] returns.)^ 7440** 7441** [[the xInit() page cache method]] 7442** ^(The xInit() method is called once for each effective 7443** call to [sqlite3_initialize()])^ 7444** (usually only once during the lifetime of the process). ^(The xInit() 7445** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7446** The intent of the xInit() method is to set up global data structures 7447** required by the custom page cache implementation. 7448** ^(If the xInit() method is NULL, then the 7449** built-in default page cache is used instead of the application defined 7450** page cache.)^ 7451** 7452** [[the xShutdown() page cache method]] 7453** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7454** It can be used to clean up 7455** any outstanding resources before process shutdown, if required. 7456** ^The xShutdown() method may be NULL. 7457** 7458** ^SQLite automatically serializes calls to the xInit method, 7459** so the xInit method need not be threadsafe. ^The 7460** xShutdown method is only called from [sqlite3_shutdown()] so it does 7461** not need to be threadsafe either. All other methods must be threadsafe 7462** in multithreaded applications. 7463** 7464** ^SQLite will never invoke xInit() more than once without an intervening 7465** call to xShutdown(). 7466** 7467** [[the xCreate() page cache methods]] 7468** ^SQLite invokes the xCreate() method to construct a new cache instance. 7469** SQLite will typically create one cache instance for each open database file, 7470** though this is not guaranteed. ^The 7471** first parameter, szPage, is the size in bytes of the pages that must 7472** be allocated by the cache. ^szPage will always a power of two. ^The 7473** second parameter szExtra is a number of bytes of extra storage 7474** associated with each page cache entry. ^The szExtra parameter will 7475** a number less than 250. SQLite will use the 7476** extra szExtra bytes on each page to store metadata about the underlying 7477** database page on disk. The value passed into szExtra depends 7478** on the SQLite version, the target platform, and how SQLite was compiled. 7479** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7480** created will be used to cache database pages of a file stored on disk, or 7481** false if it is used for an in-memory database. The cache implementation 7482** does not have to do anything special based with the value of bPurgeable; 7483** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7484** never invoke xUnpin() except to deliberately delete a page. 7485** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7486** false will always have the "discard" flag set to true. 7487** ^Hence, a cache created with bPurgeable false will 7488** never contain any unpinned pages. 7489** 7490** [[the xCachesize() page cache method]] 7491** ^(The xCachesize() method may be called at any time by SQLite to set the 7492** suggested maximum cache-size (number of pages stored by) the cache 7493** instance passed as the first argument. This is the value configured using 7494** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7495** parameter, the implementation is not required to do anything with this 7496** value; it is advisory only. 7497** 7498** [[the xPagecount() page cache methods]] 7499** The xPagecount() method must return the number of pages currently 7500** stored in the cache, both pinned and unpinned. 7501** 7502** [[the xFetch() page cache methods]] 7503** The xFetch() method locates a page in the cache and returns a pointer to 7504** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7505** The pBuf element of the returned sqlite3_pcache_page object will be a 7506** pointer to a buffer of szPage bytes used to store the content of a 7507** single database page. The pExtra element of sqlite3_pcache_page will be 7508** a pointer to the szExtra bytes of extra storage that SQLite has requested 7509** for each entry in the page cache. 7510** 7511** The page to be fetched is determined by the key. ^The minimum key value 7512** is 1. After it has been retrieved using xFetch, the page is considered 7513** to be "pinned". 7514** 7515** If the requested page is already in the page cache, then the page cache 7516** implementation must return a pointer to the page buffer with its content 7517** intact. If the requested page is not already in the cache, then the 7518** cache implementation should use the value of the createFlag 7519** parameter to help it determined what action to take: 7520** 7521** <table border=1 width=85% align=center> 7522** <tr><th> createFlag <th> Behavior when page is not already in cache 7523** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7524** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7525** Otherwise return NULL. 7526** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7527** NULL if allocating a new page is effectively impossible. 7528** </table> 7529** 7530** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7531** will only use a createFlag of 2 after a prior call with a createFlag of 1 7532** failed.)^ In between the to xFetch() calls, SQLite may 7533** attempt to unpin one or more cache pages by spilling the content of 7534** pinned pages to disk and synching the operating system disk cache. 7535** 7536** [[the xUnpin() page cache method]] 7537** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7538** as its second argument. If the third parameter, discard, is non-zero, 7539** then the page must be evicted from the cache. 7540** ^If the discard parameter is 7541** zero, then the page may be discarded or retained at the discretion of 7542** page cache implementation. ^The page cache implementation 7543** may choose to evict unpinned pages at any time. 7544** 7545** The cache must not perform any reference counting. A single 7546** call to xUnpin() unpins the page regardless of the number of prior calls 7547** to xFetch(). 7548** 7549** [[the xRekey() page cache methods]] 7550** The xRekey() method is used to change the key value associated with the 7551** page passed as the second argument. If the cache 7552** previously contains an entry associated with newKey, it must be 7553** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7554** to be pinned. 7555** 7556** When SQLite calls the xTruncate() method, the cache must discard all 7557** existing cache entries with page numbers (keys) greater than or equal 7558** to the value of the iLimit parameter passed to xTruncate(). If any 7559** of these pages are pinned, they are implicitly unpinned, meaning that 7560** they can be safely discarded. 7561** 7562** [[the xDestroy() page cache method]] 7563** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7564** All resources associated with the specified cache should be freed. ^After 7565** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7566** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7567** functions. 7568** 7569** [[the xShrink() page cache method]] 7570** ^SQLite invokes the xShrink() method when it wants the page cache to 7571** free up as much of heap memory as possible. The page cache implementation 7572** is not obligated to free any memory, but well-behaved implementations should 7573** do their best. 7574*/ 7575typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7576struct sqlite3_pcache_methods2 { 7577 int iVersion; 7578 void *pArg; 7579 int (*xInit)(void*); 7580 void (*xShutdown)(void*); 7581 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7582 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7583 int (*xPagecount)(sqlite3_pcache*); 7584 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7585 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7586 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7587 unsigned oldKey, unsigned newKey); 7588 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7589 void (*xDestroy)(sqlite3_pcache*); 7590 void (*xShrink)(sqlite3_pcache*); 7591}; 7592 7593/* 7594** This is the obsolete pcache_methods object that has now been replaced 7595** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7596** retained in the header file for backwards compatibility only. 7597*/ 7598typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7599struct sqlite3_pcache_methods { 7600 void *pArg; 7601 int (*xInit)(void*); 7602 void (*xShutdown)(void*); 7603 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7604 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7605 int (*xPagecount)(sqlite3_pcache*); 7606 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7607 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7608 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7609 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7610 void (*xDestroy)(sqlite3_pcache*); 7611}; 7612 7613 7614/* 7615** CAPI3REF: Online Backup Object 7616** 7617** The sqlite3_backup object records state information about an ongoing 7618** online backup operation. ^The sqlite3_backup object is created by 7619** a call to [sqlite3_backup_init()] and is destroyed by a call to 7620** [sqlite3_backup_finish()]. 7621** 7622** See Also: [Using the SQLite Online Backup API] 7623*/ 7624typedef struct sqlite3_backup sqlite3_backup; 7625 7626/* 7627** CAPI3REF: Online Backup API. 7628** 7629** The backup API copies the content of one database into another. 7630** It is useful either for creating backups of databases or 7631** for copying in-memory databases to or from persistent files. 7632** 7633** See Also: [Using the SQLite Online Backup API] 7634** 7635** ^SQLite holds a write transaction open on the destination database file 7636** for the duration of the backup operation. 7637** ^The source database is read-locked only while it is being read; 7638** it is not locked continuously for the entire backup operation. 7639** ^Thus, the backup may be performed on a live source database without 7640** preventing other database connections from 7641** reading or writing to the source database while the backup is underway. 7642** 7643** ^(To perform a backup operation: 7644** <ol> 7645** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7646** backup, 7647** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7648** the data between the two databases, and finally 7649** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7650** associated with the backup operation. 7651** </ol>)^ 7652** There should be exactly one call to sqlite3_backup_finish() for each 7653** successful call to sqlite3_backup_init(). 7654** 7655** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7656** 7657** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7658** [database connection] associated with the destination database 7659** and the database name, respectively. 7660** ^The database name is "main" for the main database, "temp" for the 7661** temporary database, or the name specified after the AS keyword in 7662** an [ATTACH] statement for an attached database. 7663** ^The S and M arguments passed to 7664** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7665** and database name of the source database, respectively. 7666** ^The source and destination [database connections] (parameters S and D) 7667** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7668** an error. 7669** 7670** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7671** there is already a read or read-write transaction open on the 7672** destination database. 7673** 7674** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7675** returned and an error code and error message are stored in the 7676** destination [database connection] D. 7677** ^The error code and message for the failed call to sqlite3_backup_init() 7678** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7679** [sqlite3_errmsg16()] functions. 7680** ^A successful call to sqlite3_backup_init() returns a pointer to an 7681** [sqlite3_backup] object. 7682** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7683** sqlite3_backup_finish() functions to perform the specified backup 7684** operation. 7685** 7686** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7687** 7688** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7689** the source and destination databases specified by [sqlite3_backup] object B. 7690** ^If N is negative, all remaining source pages are copied. 7691** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7692** are still more pages to be copied, then the function returns [SQLITE_OK]. 7693** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7694** from source to destination, then it returns [SQLITE_DONE]. 7695** ^If an error occurs while running sqlite3_backup_step(B,N), 7696** then an [error code] is returned. ^As well as [SQLITE_OK] and 7697** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7698** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7699** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7700** 7701** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7702** <ol> 7703** <li> the destination database was opened read-only, or 7704** <li> the destination database is using write-ahead-log journaling 7705** and the destination and source page sizes differ, or 7706** <li> the destination database is an in-memory database and the 7707** destination and source page sizes differ. 7708** </ol>)^ 7709** 7710** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7711** the [sqlite3_busy_handler | busy-handler function] 7712** is invoked (if one is specified). ^If the 7713** busy-handler returns non-zero before the lock is available, then 7714** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7715** sqlite3_backup_step() can be retried later. ^If the source 7716** [database connection] 7717** is being used to write to the source database when sqlite3_backup_step() 7718** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7719** case the call to sqlite3_backup_step() can be retried later on. ^(If 7720** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7721** [SQLITE_READONLY] is returned, then 7722** there is no point in retrying the call to sqlite3_backup_step(). These 7723** errors are considered fatal.)^ The application must accept 7724** that the backup operation has failed and pass the backup operation handle 7725** to the sqlite3_backup_finish() to release associated resources. 7726** 7727** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7728** on the destination file. ^The exclusive lock is not released until either 7729** sqlite3_backup_finish() is called or the backup operation is complete 7730** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7731** sqlite3_backup_step() obtains a [shared lock] on the source database that 7732** lasts for the duration of the sqlite3_backup_step() call. 7733** ^Because the source database is not locked between calls to 7734** sqlite3_backup_step(), the source database may be modified mid-way 7735** through the backup process. ^If the source database is modified by an 7736** external process or via a database connection other than the one being 7737** used by the backup operation, then the backup will be automatically 7738** restarted by the next call to sqlite3_backup_step(). ^If the source 7739** database is modified by the using the same database connection as is used 7740** by the backup operation, then the backup database is automatically 7741** updated at the same time. 7742** 7743** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7744** 7745** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7746** application wishes to abandon the backup operation, the application 7747** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7748** ^The sqlite3_backup_finish() interfaces releases all 7749** resources associated with the [sqlite3_backup] object. 7750** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7751** active write-transaction on the destination database is rolled back. 7752** The [sqlite3_backup] object is invalid 7753** and may not be used following a call to sqlite3_backup_finish(). 7754** 7755** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7756** sqlite3_backup_step() errors occurred, regardless or whether or not 7757** sqlite3_backup_step() completed. 7758** ^If an out-of-memory condition or IO error occurred during any prior 7759** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7760** sqlite3_backup_finish() returns the corresponding [error code]. 7761** 7762** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7763** is not a permanent error and does not affect the return value of 7764** sqlite3_backup_finish(). 7765** 7766** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7767** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7768** 7769** ^The sqlite3_backup_remaining() routine returns the number of pages still 7770** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7771** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7772** in the source database at the conclusion of the most recent 7773** sqlite3_backup_step(). 7774** ^(The values returned by these functions are only updated by 7775** sqlite3_backup_step(). If the source database is modified in a way that 7776** changes the size of the source database or the number of pages remaining, 7777** those changes are not reflected in the output of sqlite3_backup_pagecount() 7778** and sqlite3_backup_remaining() until after the next 7779** sqlite3_backup_step().)^ 7780** 7781** <b>Concurrent Usage of Database Handles</b> 7782** 7783** ^The source [database connection] may be used by the application for other 7784** purposes while a backup operation is underway or being initialized. 7785** ^If SQLite is compiled and configured to support threadsafe database 7786** connections, then the source database connection may be used concurrently 7787** from within other threads. 7788** 7789** However, the application must guarantee that the destination 7790** [database connection] is not passed to any other API (by any thread) after 7791** sqlite3_backup_init() is called and before the corresponding call to 7792** sqlite3_backup_finish(). SQLite does not currently check to see 7793** if the application incorrectly accesses the destination [database connection] 7794** and so no error code is reported, but the operations may malfunction 7795** nevertheless. Use of the destination database connection while a 7796** backup is in progress might also also cause a mutex deadlock. 7797** 7798** If running in [shared cache mode], the application must 7799** guarantee that the shared cache used by the destination database 7800** is not accessed while the backup is running. In practice this means 7801** that the application must guarantee that the disk file being 7802** backed up to is not accessed by any connection within the process, 7803** not just the specific connection that was passed to sqlite3_backup_init(). 7804** 7805** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7806** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7807** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7808** APIs are not strictly speaking threadsafe. If they are invoked at the 7809** same time as another thread is invoking sqlite3_backup_step() it is 7810** possible that they return invalid values. 7811*/ 7812sqlite3_backup *sqlite3_backup_init( 7813 sqlite3 *pDest, /* Destination database handle */ 7814 const char *zDestName, /* Destination database name */ 7815 sqlite3 *pSource, /* Source database handle */ 7816 const char *zSourceName /* Source database name */ 7817); 7818int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7819int sqlite3_backup_finish(sqlite3_backup *p); 7820int sqlite3_backup_remaining(sqlite3_backup *p); 7821int sqlite3_backup_pagecount(sqlite3_backup *p); 7822 7823/* 7824** CAPI3REF: Unlock Notification 7825** METHOD: sqlite3 7826** 7827** ^When running in shared-cache mode, a database operation may fail with 7828** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7829** individual tables within the shared-cache cannot be obtained. See 7830** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7831** ^This API may be used to register a callback that SQLite will invoke 7832** when the connection currently holding the required lock relinquishes it. 7833** ^This API is only available if the library was compiled with the 7834** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7835** 7836** See Also: [Using the SQLite Unlock Notification Feature]. 7837** 7838** ^Shared-cache locks are released when a database connection concludes 7839** its current transaction, either by committing it or rolling it back. 7840** 7841** ^When a connection (known as the blocked connection) fails to obtain a 7842** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7843** identity of the database connection (the blocking connection) that 7844** has locked the required resource is stored internally. ^After an 7845** application receives an SQLITE_LOCKED error, it may call the 7846** sqlite3_unlock_notify() method with the blocked connection handle as 7847** the first argument to register for a callback that will be invoked 7848** when the blocking connections current transaction is concluded. ^The 7849** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7850** call that concludes the blocking connections transaction. 7851** 7852** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7853** there is a chance that the blocking connection will have already 7854** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7855** If this happens, then the specified callback is invoked immediately, 7856** from within the call to sqlite3_unlock_notify().)^ 7857** 7858** ^If the blocked connection is attempting to obtain a write-lock on a 7859** shared-cache table, and more than one other connection currently holds 7860** a read-lock on the same table, then SQLite arbitrarily selects one of 7861** the other connections to use as the blocking connection. 7862** 7863** ^(There may be at most one unlock-notify callback registered by a 7864** blocked connection. If sqlite3_unlock_notify() is called when the 7865** blocked connection already has a registered unlock-notify callback, 7866** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7867** called with a NULL pointer as its second argument, then any existing 7868** unlock-notify callback is canceled. ^The blocked connections 7869** unlock-notify callback may also be canceled by closing the blocked 7870** connection using [sqlite3_close()]. 7871** 7872** The unlock-notify callback is not reentrant. If an application invokes 7873** any sqlite3_xxx API functions from within an unlock-notify callback, a 7874** crash or deadlock may be the result. 7875** 7876** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7877** returns SQLITE_OK. 7878** 7879** <b>Callback Invocation Details</b> 7880** 7881** When an unlock-notify callback is registered, the application provides a 7882** single void* pointer that is passed to the callback when it is invoked. 7883** However, the signature of the callback function allows SQLite to pass 7884** it an array of void* context pointers. The first argument passed to 7885** an unlock-notify callback is a pointer to an array of void* pointers, 7886** and the second is the number of entries in the array. 7887** 7888** When a blocking connections transaction is concluded, there may be 7889** more than one blocked connection that has registered for an unlock-notify 7890** callback. ^If two or more such blocked connections have specified the 7891** same callback function, then instead of invoking the callback function 7892** multiple times, it is invoked once with the set of void* context pointers 7893** specified by the blocked connections bundled together into an array. 7894** This gives the application an opportunity to prioritize any actions 7895** related to the set of unblocked database connections. 7896** 7897** <b>Deadlock Detection</b> 7898** 7899** Assuming that after registering for an unlock-notify callback a 7900** database waits for the callback to be issued before taking any further 7901** action (a reasonable assumption), then using this API may cause the 7902** application to deadlock. For example, if connection X is waiting for 7903** connection Y's transaction to be concluded, and similarly connection 7904** Y is waiting on connection X's transaction, then neither connection 7905** will proceed and the system may remain deadlocked indefinitely. 7906** 7907** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7908** detection. ^If a given call to sqlite3_unlock_notify() would put the 7909** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7910** unlock-notify callback is registered. The system is said to be in 7911** a deadlocked state if connection A has registered for an unlock-notify 7912** callback on the conclusion of connection B's transaction, and connection 7913** B has itself registered for an unlock-notify callback when connection 7914** A's transaction is concluded. ^Indirect deadlock is also detected, so 7915** the system is also considered to be deadlocked if connection B has 7916** registered for an unlock-notify callback on the conclusion of connection 7917** C's transaction, where connection C is waiting on connection A. ^Any 7918** number of levels of indirection are allowed. 7919** 7920** <b>The "DROP TABLE" Exception</b> 7921** 7922** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7923** always appropriate to call sqlite3_unlock_notify(). There is however, 7924** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7925** SQLite checks if there are any currently executing SELECT statements 7926** that belong to the same connection. If there are, SQLITE_LOCKED is 7927** returned. In this case there is no "blocking connection", so invoking 7928** sqlite3_unlock_notify() results in the unlock-notify callback being 7929** invoked immediately. If the application then re-attempts the "DROP TABLE" 7930** or "DROP INDEX" query, an infinite loop might be the result. 7931** 7932** One way around this problem is to check the extended error code returned 7933** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7934** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7935** the special "DROP TABLE/INDEX" case, the extended error code is just 7936** SQLITE_LOCKED.)^ 7937*/ 7938int sqlite3_unlock_notify( 7939 sqlite3 *pBlocked, /* Waiting connection */ 7940 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7941 void *pNotifyArg /* Argument to pass to xNotify */ 7942); 7943 7944 7945/* 7946** CAPI3REF: String Comparison 7947** 7948** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7949** and extensions to compare the contents of two buffers containing UTF-8 7950** strings in a case-independent fashion, using the same definition of "case 7951** independence" that SQLite uses internally when comparing identifiers. 7952*/ 7953int sqlite3_stricmp(const char *, const char *); 7954int sqlite3_strnicmp(const char *, const char *, int); 7955 7956/* 7957** CAPI3REF: String Globbing 7958* 7959** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7960** string X matches the [GLOB] pattern P. 7961** ^The definition of [GLOB] pattern matching used in 7962** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7963** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7964** is case sensitive. 7965** 7966** Note that this routine returns zero on a match and non-zero if the strings 7967** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7968** 7969** See also: [sqlite3_strlike()]. 7970*/ 7971int sqlite3_strglob(const char *zGlob, const char *zStr); 7972 7973/* 7974** CAPI3REF: String LIKE Matching 7975* 7976** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7977** string X matches the [LIKE] pattern P with escape character E. 7978** ^The definition of [LIKE] pattern matching used in 7979** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7980** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7981** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7982** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7983** insensitive - equivalent upper and lower case ASCII characters match 7984** one another. 7985** 7986** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7987** only ASCII characters are case folded. 7988** 7989** Note that this routine returns zero on a match and non-zero if the strings 7990** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7991** 7992** See also: [sqlite3_strglob()]. 7993*/ 7994int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7995 7996/* 7997** CAPI3REF: Error Logging Interface 7998** 7999** ^The [sqlite3_log()] interface writes a message into the [error log] 8000** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8001** ^If logging is enabled, the zFormat string and subsequent arguments are 8002** used with [sqlite3_snprintf()] to generate the final output string. 8003** 8004** The sqlite3_log() interface is intended for use by extensions such as 8005** virtual tables, collating functions, and SQL functions. While there is 8006** nothing to prevent an application from calling sqlite3_log(), doing so 8007** is considered bad form. 8008** 8009** The zFormat string must not be NULL. 8010** 8011** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8012** will not use dynamically allocated memory. The log message is stored in 8013** a fixed-length buffer on the stack. If the log message is longer than 8014** a few hundred characters, it will be truncated to the length of the 8015** buffer. 8016*/ 8017void sqlite3_log(int iErrCode, const char *zFormat, ...); 8018 8019/* 8020** CAPI3REF: Write-Ahead Log Commit Hook 8021** METHOD: sqlite3 8022** 8023** ^The [sqlite3_wal_hook()] function is used to register a callback that 8024** is invoked each time data is committed to a database in wal mode. 8025** 8026** ^(The callback is invoked by SQLite after the commit has taken place and 8027** the associated write-lock on the database released)^, so the implementation 8028** may read, write or [checkpoint] the database as required. 8029** 8030** ^The first parameter passed to the callback function when it is invoked 8031** is a copy of the third parameter passed to sqlite3_wal_hook() when 8032** registering the callback. ^The second is a copy of the database handle. 8033** ^The third parameter is the name of the database that was written to - 8034** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8035** is the number of pages currently in the write-ahead log file, 8036** including those that were just committed. 8037** 8038** The callback function should normally return [SQLITE_OK]. ^If an error 8039** code is returned, that error will propagate back up through the 8040** SQLite code base to cause the statement that provoked the callback 8041** to report an error, though the commit will have still occurred. If the 8042** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8043** that does not correspond to any valid SQLite error code, the results 8044** are undefined. 8045** 8046** A single database handle may have at most a single write-ahead log callback 8047** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8048** previously registered write-ahead log callback. ^Note that the 8049** [sqlite3_wal_autocheckpoint()] interface and the 8050** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8051** overwrite any prior [sqlite3_wal_hook()] settings. 8052*/ 8053void *sqlite3_wal_hook( 8054 sqlite3*, 8055 int(*)(void *,sqlite3*,const char*,int), 8056 void* 8057); 8058 8059/* 8060** CAPI3REF: Configure an auto-checkpoint 8061** METHOD: sqlite3 8062** 8063** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8064** [sqlite3_wal_hook()] that causes any database on [database connection] D 8065** to automatically [checkpoint] 8066** after committing a transaction if there are N or 8067** more frames in the [write-ahead log] file. ^Passing zero or 8068** a negative value as the nFrame parameter disables automatic 8069** checkpoints entirely. 8070** 8071** ^The callback registered by this function replaces any existing callback 8072** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8073** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8074** configured by this function. 8075** 8076** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8077** from SQL. 8078** 8079** ^Checkpoints initiated by this mechanism are 8080** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8081** 8082** ^Every new [database connection] defaults to having the auto-checkpoint 8083** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8084** pages. The use of this interface 8085** is only necessary if the default setting is found to be suboptimal 8086** for a particular application. 8087*/ 8088int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8089 8090/* 8091** CAPI3REF: Checkpoint a database 8092** METHOD: sqlite3 8093** 8094** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8095** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8096** 8097** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8098** [write-ahead log] for database X on [database connection] D to be 8099** transferred into the database file and for the write-ahead log to 8100** be reset. See the [checkpointing] documentation for addition 8101** information. 8102** 8103** This interface used to be the only way to cause a checkpoint to 8104** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8105** interface was added. This interface is retained for backwards 8106** compatibility and as a convenience for applications that need to manually 8107** start a callback but which do not need the full power (and corresponding 8108** complication) of [sqlite3_wal_checkpoint_v2()]. 8109*/ 8110int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8111 8112/* 8113** CAPI3REF: Checkpoint a database 8114** METHOD: sqlite3 8115** 8116** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8117** operation on database X of [database connection] D in mode M. Status 8118** information is written back into integers pointed to by L and C.)^ 8119** ^(The M parameter must be a valid [checkpoint mode]:)^ 8120** 8121** <dl> 8122** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8123** ^Checkpoint as many frames as possible without waiting for any database 8124** readers or writers to finish, then sync the database file if all frames 8125** in the log were checkpointed. ^The [busy-handler callback] 8126** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8127** ^On the other hand, passive mode might leave the checkpoint unfinished 8128** if there are concurrent readers or writers. 8129** 8130** <dt>SQLITE_CHECKPOINT_FULL<dd> 8131** ^This mode blocks (it invokes the 8132** [sqlite3_busy_handler|busy-handler callback]) until there is no 8133** database writer and all readers are reading from the most recent database 8134** snapshot. ^It then checkpoints all frames in the log file and syncs the 8135** database file. ^This mode blocks new database writers while it is pending, 8136** but new database readers are allowed to continue unimpeded. 8137** 8138** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8139** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8140** that after checkpointing the log file it blocks (calls the 8141** [busy-handler callback]) 8142** until all readers are reading from the database file only. ^This ensures 8143** that the next writer will restart the log file from the beginning. 8144** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8145** database writer attempts while it is pending, but does not impede readers. 8146** 8147** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8148** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8149** addition that it also truncates the log file to zero bytes just prior 8150** to a successful return. 8151** </dl> 8152** 8153** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8154** the log file or to -1 if the checkpoint could not run because 8155** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8156** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8157** log file (including any that were already checkpointed before the function 8158** was called) or to -1 if the checkpoint could not run due to an error or 8159** because the database is not in WAL mode. ^Note that upon successful 8160** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8161** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8162** 8163** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8164** any other process is running a checkpoint operation at the same time, the 8165** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8166** busy-handler configured, it will not be invoked in this case. 8167** 8168** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8169** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8170** obtained immediately, and a busy-handler is configured, it is invoked and 8171** the writer lock retried until either the busy-handler returns 0 or the lock 8172** is successfully obtained. ^The busy-handler is also invoked while waiting for 8173** database readers as described above. ^If the busy-handler returns 0 before 8174** the writer lock is obtained or while waiting for database readers, the 8175** checkpoint operation proceeds from that point in the same way as 8176** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8177** without blocking any further. ^SQLITE_BUSY is returned in this case. 8178** 8179** ^If parameter zDb is NULL or points to a zero length string, then the 8180** specified operation is attempted on all WAL databases [attached] to 8181** [database connection] db. In this case the 8182** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8183** an SQLITE_BUSY error is encountered when processing one or more of the 8184** attached WAL databases, the operation is still attempted on any remaining 8185** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8186** error occurs while processing an attached database, processing is abandoned 8187** and the error code is returned to the caller immediately. ^If no error 8188** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8189** databases, SQLITE_OK is returned. 8190** 8191** ^If database zDb is the name of an attached database that is not in WAL 8192** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8193** zDb is not NULL (or a zero length string) and is not the name of any 8194** attached database, SQLITE_ERROR is returned to the caller. 8195** 8196** ^Unless it returns SQLITE_MISUSE, 8197** the sqlite3_wal_checkpoint_v2() interface 8198** sets the error information that is queried by 8199** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8200** 8201** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8202** from SQL. 8203*/ 8204int sqlite3_wal_checkpoint_v2( 8205 sqlite3 *db, /* Database handle */ 8206 const char *zDb, /* Name of attached database (or NULL) */ 8207 int eMode, /* SQLITE_CHECKPOINT_* value */ 8208 int *pnLog, /* OUT: Size of WAL log in frames */ 8209 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8210); 8211 8212/* 8213** CAPI3REF: Checkpoint Mode Values 8214** KEYWORDS: {checkpoint mode} 8215** 8216** These constants define all valid values for the "checkpoint mode" passed 8217** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8218** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8219** meaning of each of these checkpoint modes. 8220*/ 8221#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8222#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8223#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8224#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8225 8226/* 8227** CAPI3REF: Virtual Table Interface Configuration 8228** 8229** This function may be called by either the [xConnect] or [xCreate] method 8230** of a [virtual table] implementation to configure 8231** various facets of the virtual table interface. 8232** 8233** If this interface is invoked outside the context of an xConnect or 8234** xCreate virtual table method then the behavior is undefined. 8235** 8236** At present, there is only one option that may be configured using 8237** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8238** may be added in the future. 8239*/ 8240int sqlite3_vtab_config(sqlite3*, int op, ...); 8241 8242/* 8243** CAPI3REF: Virtual Table Configuration Options 8244** 8245** These macros define the various options to the 8246** [sqlite3_vtab_config()] interface that [virtual table] implementations 8247** can use to customize and optimize their behavior. 8248** 8249** <dl> 8250** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8251** <dd>Calls of the form 8252** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8253** where X is an integer. If X is zero, then the [virtual table] whose 8254** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8255** support constraints. In this configuration (which is the default) if 8256** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8257** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8258** specified as part of the users SQL statement, regardless of the actual 8259** ON CONFLICT mode specified. 8260** 8261** If X is non-zero, then the virtual table implementation guarantees 8262** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8263** any modifications to internal or persistent data structures have been made. 8264** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8265** is able to roll back a statement or database transaction, and abandon 8266** or continue processing the current SQL statement as appropriate. 8267** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8268** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8269** had been ABORT. 8270** 8271** Virtual table implementations that are required to handle OR REPLACE 8272** must do so within the [xUpdate] method. If a call to the 8273** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8274** CONFLICT policy is REPLACE, the virtual table implementation should 8275** silently replace the appropriate rows within the xUpdate callback and 8276** return SQLITE_OK. Or, if this is not possible, it may return 8277** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8278** constraint handling. 8279** </dl> 8280*/ 8281#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8282 8283/* 8284** CAPI3REF: Determine The Virtual Table Conflict Policy 8285** 8286** This function may only be called from within a call to the [xUpdate] method 8287** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8288** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8289** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8290** of the SQL statement that triggered the call to the [xUpdate] method of the 8291** [virtual table]. 8292*/ 8293int sqlite3_vtab_on_conflict(sqlite3 *); 8294 8295/* 8296** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 8297** 8298** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 8299** method of a [virtual table], then it returns true if and only if the 8300** column is being fetched as part of an UPDATE operation during which the 8301** column value will not change. Applications might use this to substitute 8302** a lighter-weight value to return that the corresponding [xUpdate] method 8303** understands as a "no-change" value. 8304** 8305** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 8306** the column is not changed by the UPDATE statement, they the xColumn 8307** method can optionally return without setting a result, without calling 8308** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 8309** In that case, [sqlite3_value_nochange(X)] will return true for the 8310** same column in the [xUpdate] method. 8311*/ 8312int sqlite3_vtab_nochange(sqlite3_context*); 8313 8314/* 8315** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8316** 8317** This function may only be called from within a call to the [xBestIndex] 8318** method of a [virtual table]. 8319** 8320** The first argument must be the sqlite3_index_info object that is the 8321** first parameter to the xBestIndex() method. The second argument must be 8322** an index into the aConstraint[] array belonging to the sqlite3_index_info 8323** structure passed to xBestIndex. This function returns a pointer to a buffer 8324** containing the name of the collation sequence for the corresponding 8325** constraint. 8326*/ 8327SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8328 8329/* 8330** CAPI3REF: Conflict resolution modes 8331** KEYWORDS: {conflict resolution mode} 8332** 8333** These constants are returned by [sqlite3_vtab_on_conflict()] to 8334** inform a [virtual table] implementation what the [ON CONFLICT] mode 8335** is for the SQL statement being evaluated. 8336** 8337** Note that the [SQLITE_IGNORE] constant is also used as a potential 8338** return value from the [sqlite3_set_authorizer()] callback and that 8339** [SQLITE_ABORT] is also a [result code]. 8340*/ 8341#define SQLITE_ROLLBACK 1 8342/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8343#define SQLITE_FAIL 3 8344/* #define SQLITE_ABORT 4 // Also an error code */ 8345#define SQLITE_REPLACE 5 8346 8347/* 8348** CAPI3REF: Prepared Statement Scan Status Opcodes 8349** KEYWORDS: {scanstatus options} 8350** 8351** The following constants can be used for the T parameter to the 8352** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8353** different metric for sqlite3_stmt_scanstatus() to return. 8354** 8355** When the value returned to V is a string, space to hold that string is 8356** managed by the prepared statement S and will be automatically freed when 8357** S is finalized. 8358** 8359** <dl> 8360** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8361** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8362** set to the total number of times that the X-th loop has run.</dd> 8363** 8364** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8365** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8366** to the total number of rows examined by all iterations of the X-th loop.</dd> 8367** 8368** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8369** <dd>^The "double" variable pointed to by the T parameter will be set to the 8370** query planner's estimate for the average number of rows output from each 8371** iteration of the X-th loop. If the query planner's estimates was accurate, 8372** then this value will approximate the quotient NVISIT/NLOOP and the 8373** product of this value for all prior loops with the same SELECTID will 8374** be the NLOOP value for the current loop. 8375** 8376** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8377** <dd>^The "const char *" variable pointed to by the T parameter will be set 8378** to a zero-terminated UTF-8 string containing the name of the index or table 8379** used for the X-th loop. 8380** 8381** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8382** <dd>^The "const char *" variable pointed to by the T parameter will be set 8383** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8384** description for the X-th loop. 8385** 8386** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8387** <dd>^The "int" variable pointed to by the T parameter will be set to the 8388** "select-id" for the X-th loop. The select-id identifies which query or 8389** subquery the loop is part of. The main query has a select-id of zero. 8390** The select-id is the same value as is output in the first column 8391** of an [EXPLAIN QUERY PLAN] query. 8392** </dl> 8393*/ 8394#define SQLITE_SCANSTAT_NLOOP 0 8395#define SQLITE_SCANSTAT_NVISIT 1 8396#define SQLITE_SCANSTAT_EST 2 8397#define SQLITE_SCANSTAT_NAME 3 8398#define SQLITE_SCANSTAT_EXPLAIN 4 8399#define SQLITE_SCANSTAT_SELECTID 5 8400 8401/* 8402** CAPI3REF: Prepared Statement Scan Status 8403** METHOD: sqlite3_stmt 8404** 8405** This interface returns information about the predicted and measured 8406** performance for pStmt. Advanced applications can use this 8407** interface to compare the predicted and the measured performance and 8408** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8409** 8410** Since this interface is expected to be rarely used, it is only 8411** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8412** compile-time option. 8413** 8414** The "iScanStatusOp" parameter determines which status information to return. 8415** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8416** of this interface is undefined. 8417** ^The requested measurement is written into a variable pointed to by 8418** the "pOut" parameter. 8419** Parameter "idx" identifies the specific loop to retrieve statistics for. 8420** Loops are numbered starting from zero. ^If idx is out of range - less than 8421** zero or greater than or equal to the total number of loops used to implement 8422** the statement - a non-zero value is returned and the variable that pOut 8423** points to is unchanged. 8424** 8425** ^Statistics might not be available for all loops in all statements. ^In cases 8426** where there exist loops with no available statistics, this function behaves 8427** as if the loop did not exist - it returns non-zero and leave the variable 8428** that pOut points to unchanged. 8429** 8430** See also: [sqlite3_stmt_scanstatus_reset()] 8431*/ 8432int sqlite3_stmt_scanstatus( 8433 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8434 int idx, /* Index of loop to report on */ 8435 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8436 void *pOut /* Result written here */ 8437); 8438 8439/* 8440** CAPI3REF: Zero Scan-Status Counters 8441** METHOD: sqlite3_stmt 8442** 8443** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8444** 8445** This API is only available if the library is built with pre-processor 8446** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8447*/ 8448void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8449 8450/* 8451** CAPI3REF: Flush caches to disk mid-transaction 8452** 8453** ^If a write-transaction is open on [database connection] D when the 8454** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8455** pages in the pager-cache that are not currently in use are written out 8456** to disk. A dirty page may be in use if a database cursor created by an 8457** active SQL statement is reading from it, or if it is page 1 of a database 8458** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8459** interface flushes caches for all schemas - "main", "temp", and 8460** any [attached] databases. 8461** 8462** ^If this function needs to obtain extra database locks before dirty pages 8463** can be flushed to disk, it does so. ^If those locks cannot be obtained 8464** immediately and there is a busy-handler callback configured, it is invoked 8465** in the usual manner. ^If the required lock still cannot be obtained, then 8466** the database is skipped and an attempt made to flush any dirty pages 8467** belonging to the next (if any) database. ^If any databases are skipped 8468** because locks cannot be obtained, but no other error occurs, this 8469** function returns SQLITE_BUSY. 8470** 8471** ^If any other error occurs while flushing dirty pages to disk (for 8472** example an IO error or out-of-memory condition), then processing is 8473** abandoned and an SQLite [error code] is returned to the caller immediately. 8474** 8475** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8476** 8477** ^This function does not set the database handle error code or message 8478** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8479*/ 8480int sqlite3_db_cacheflush(sqlite3*); 8481 8482/* 8483** CAPI3REF: The pre-update hook. 8484** 8485** ^These interfaces are only available if SQLite is compiled using the 8486** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8487** 8488** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8489** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8490** on a database table. 8491** ^At most one preupdate hook may be registered at a time on a single 8492** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8493** the previous setting. 8494** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8495** with a NULL pointer as the second parameter. 8496** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8497** the first parameter to callbacks. 8498** 8499** ^The preupdate hook only fires for changes to real database tables; the 8500** preupdate hook is not invoked for changes to [virtual tables] or to 8501** system tables like sqlite_master or sqlite_stat1. 8502** 8503** ^The second parameter to the preupdate callback is a pointer to 8504** the [database connection] that registered the preupdate hook. 8505** ^The third parameter to the preupdate callback is one of the constants 8506** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8507** kind of update operation that is about to occur. 8508** ^(The fourth parameter to the preupdate callback is the name of the 8509** database within the database connection that is being modified. This 8510** will be "main" for the main database or "temp" for TEMP tables or 8511** the name given after the AS keyword in the [ATTACH] statement for attached 8512** databases.)^ 8513** ^The fifth parameter to the preupdate callback is the name of the 8514** table that is being modified. 8515** 8516** For an UPDATE or DELETE operation on a [rowid table], the sixth 8517** parameter passed to the preupdate callback is the initial [rowid] of the 8518** row being modified or deleted. For an INSERT operation on a rowid table, 8519** or any operation on a WITHOUT ROWID table, the value of the sixth 8520** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8521** seventh parameter is the final rowid value of the row being inserted 8522** or updated. The value of the seventh parameter passed to the callback 8523** function is not defined for operations on WITHOUT ROWID tables, or for 8524** INSERT operations on rowid tables. 8525** 8526** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8527** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8528** provide additional information about a preupdate event. These routines 8529** may only be called from within a preupdate callback. Invoking any of 8530** these routines from outside of a preupdate callback or with a 8531** [database connection] pointer that is different from the one supplied 8532** to the preupdate callback results in undefined and probably undesirable 8533** behavior. 8534** 8535** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8536** in the row that is being inserted, updated, or deleted. 8537** 8538** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8539** a [protected sqlite3_value] that contains the value of the Nth column of 8540** the table row before it is updated. The N parameter must be between 0 8541** and one less than the number of columns or the behavior will be 8542** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8543** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8544** behavior is undefined. The [sqlite3_value] that P points to 8545** will be destroyed when the preupdate callback returns. 8546** 8547** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8548** a [protected sqlite3_value] that contains the value of the Nth column of 8549** the table row after it is updated. The N parameter must be between 0 8550** and one less than the number of columns or the behavior will be 8551** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8552** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8553** behavior is undefined. The [sqlite3_value] that P points to 8554** will be destroyed when the preupdate callback returns. 8555** 8556** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8557** callback was invoked as a result of a direct insert, update, or delete 8558** operation; or 1 for inserts, updates, or deletes invoked by top-level 8559** triggers; or 2 for changes resulting from triggers called by top-level 8560** triggers; and so forth. 8561** 8562** See also: [sqlite3_update_hook()] 8563*/ 8564#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8565void *sqlite3_preupdate_hook( 8566 sqlite3 *db, 8567 void(*xPreUpdate)( 8568 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8569 sqlite3 *db, /* Database handle */ 8570 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8571 char const *zDb, /* Database name */ 8572 char const *zName, /* Table name */ 8573 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8574 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8575 ), 8576 void* 8577); 8578int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8579int sqlite3_preupdate_count(sqlite3 *); 8580int sqlite3_preupdate_depth(sqlite3 *); 8581int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8582#endif 8583 8584/* 8585** CAPI3REF: Low-level system error code 8586** 8587** ^Attempt to return the underlying operating system error code or error 8588** number that caused the most recent I/O error or failure to open a file. 8589** The return value is OS-dependent. For example, on unix systems, after 8590** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8591** called to get back the underlying "errno" that caused the problem, such 8592** as ENOSPC, EAUTH, EISDIR, and so forth. 8593*/ 8594int sqlite3_system_errno(sqlite3*); 8595 8596/* 8597** CAPI3REF: Database Snapshot 8598** KEYWORDS: {snapshot} {sqlite3_snapshot} 8599** EXPERIMENTAL 8600** 8601** An instance of the snapshot object records the state of a [WAL mode] 8602** database for some specific point in history. 8603** 8604** In [WAL mode], multiple [database connections] that are open on the 8605** same database file can each be reading a different historical version 8606** of the database file. When a [database connection] begins a read 8607** transaction, that connection sees an unchanging copy of the database 8608** as it existed for the point in time when the transaction first started. 8609** Subsequent changes to the database from other connections are not seen 8610** by the reader until a new read transaction is started. 8611** 8612** The sqlite3_snapshot object records state information about an historical 8613** version of the database file so that it is possible to later open a new read 8614** transaction that sees that historical version of the database rather than 8615** the most recent version. 8616** 8617** The constructor for this object is [sqlite3_snapshot_get()]. The 8618** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8619** to an historical snapshot (if possible). The destructor for 8620** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8621*/ 8622typedef struct sqlite3_snapshot { 8623 unsigned char hidden[48]; 8624} sqlite3_snapshot; 8625 8626/* 8627** CAPI3REF: Record A Database Snapshot 8628** EXPERIMENTAL 8629** 8630** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8631** new [sqlite3_snapshot] object that records the current state of 8632** schema S in database connection D. ^On success, the 8633** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8634** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8635** If there is not already a read-transaction open on schema S when 8636** this function is called, one is opened automatically. 8637** 8638** The following must be true for this function to succeed. If any of 8639** the following statements are false when sqlite3_snapshot_get() is 8640** called, SQLITE_ERROR is returned. The final value of *P is undefined 8641** in this case. 8642** 8643** <ul> 8644** <li> The database handle must be in [autocommit mode]. 8645** 8646** <li> Schema S of [database connection] D must be a [WAL mode] database. 8647** 8648** <li> There must not be a write transaction open on schema S of database 8649** connection D. 8650** 8651** <li> One or more transactions must have been written to the current wal 8652** file since it was created on disk (by any connection). This means 8653** that a snapshot cannot be taken on a wal mode database with no wal 8654** file immediately after it is first opened. At least one transaction 8655** must be written to it first. 8656** </ul> 8657** 8658** This function may also return SQLITE_NOMEM. If it is called with the 8659** database handle in autocommit mode but fails for some other reason, 8660** whether or not a read transaction is opened on schema S is undefined. 8661** 8662** The [sqlite3_snapshot] object returned from a successful call to 8663** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8664** to avoid a memory leak. 8665** 8666** The [sqlite3_snapshot_get()] interface is only available when the 8667** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8668*/ 8669SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8670 sqlite3 *db, 8671 const char *zSchema, 8672 sqlite3_snapshot **ppSnapshot 8673); 8674 8675/* 8676** CAPI3REF: Start a read transaction on an historical snapshot 8677** EXPERIMENTAL 8678** 8679** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8680** read transaction for schema S of 8681** [database connection] D such that the read transaction 8682** refers to historical [snapshot] P, rather than the most 8683** recent change to the database. 8684** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8685** or an appropriate [error code] if it fails. 8686** 8687** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8688** the first operation following the [BEGIN] that takes the schema S 8689** out of [autocommit mode]. 8690** ^In other words, schema S must not currently be in 8691** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8692** database connection D must be out of [autocommit mode]. 8693** ^A [snapshot] will fail to open if it has been overwritten by a 8694** [checkpoint]. 8695** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8696** database connection D does not know that the database file for 8697** schema S is in [WAL mode]. A database connection might not know 8698** that the database file is in [WAL mode] if there has been no prior 8699** I/O on that database connection, or if the database entered [WAL mode] 8700** after the most recent I/O on the database connection.)^ 8701** (Hint: Run "[PRAGMA application_id]" against a newly opened 8702** database connection in order to make it ready to use snapshots.) 8703** 8704** The [sqlite3_snapshot_open()] interface is only available when the 8705** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8706*/ 8707SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8708 sqlite3 *db, 8709 const char *zSchema, 8710 sqlite3_snapshot *pSnapshot 8711); 8712 8713/* 8714** CAPI3REF: Destroy a snapshot 8715** EXPERIMENTAL 8716** 8717** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8718** The application must eventually free every [sqlite3_snapshot] object 8719** using this routine to avoid a memory leak. 8720** 8721** The [sqlite3_snapshot_free()] interface is only available when the 8722** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8723*/ 8724SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8725 8726/* 8727** CAPI3REF: Compare the ages of two snapshot handles. 8728** EXPERIMENTAL 8729** 8730** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8731** of two valid snapshot handles. 8732** 8733** If the two snapshot handles are not associated with the same database 8734** file, the result of the comparison is undefined. 8735** 8736** Additionally, the result of the comparison is only valid if both of the 8737** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8738** last time the wal file was deleted. The wal file is deleted when the 8739** database is changed back to rollback mode or when the number of database 8740** clients drops to zero. If either snapshot handle was obtained before the 8741** wal file was last deleted, the value returned by this function 8742** is undefined. 8743** 8744** Otherwise, this API returns a negative value if P1 refers to an older 8745** snapshot than P2, zero if the two handles refer to the same database 8746** snapshot, and a positive value if P1 is a newer snapshot than P2. 8747*/ 8748SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8749 sqlite3_snapshot *p1, 8750 sqlite3_snapshot *p2 8751); 8752 8753/* 8754** CAPI3REF: Recover snapshots from a wal file 8755** EXPERIMENTAL 8756** 8757** If all connections disconnect from a database file but do not perform 8758** a checkpoint, the existing wal file is opened along with the database 8759** file the next time the database is opened. At this point it is only 8760** possible to successfully call sqlite3_snapshot_open() to open the most 8761** recent snapshot of the database (the one at the head of the wal file), 8762** even though the wal file may contain other valid snapshots for which 8763** clients have sqlite3_snapshot handles. 8764** 8765** This function attempts to scan the wal file associated with database zDb 8766** of database handle db and make all valid snapshots available to 8767** sqlite3_snapshot_open(). It is an error if there is already a read 8768** transaction open on the database, or if the database is not a wal mode 8769** database. 8770** 8771** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8772*/ 8773SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8774 8775/* 8776** CAPI3REF: Serialize a database 8777** 8778** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 8779** that is a serialization of the S database on [database connection] D. 8780** If P is not a NULL pointer, then the size of the database in bytes 8781** is written into *P. 8782** 8783** For an ordinary on-disk database file, the serialization is just a 8784** copy of the disk file. For an in-memory database or a "TEMP" database, 8785** the serialization is the same sequence of bytes which would be written 8786** to disk if that database where backed up to disk. 8787** 8788** The usual case is that sqlite3_serialize() copies the serialization of 8789** the database into memory obtained from [sqlite3_malloc64()] and returns 8790** a pointer to that memory. The caller is responsible for freeing the 8791** returned value to avoid a memory leak. However, if the F argument 8792** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 8793** are made, and the sqlite3_serialize() function will return a pointer 8794** to the contiguous memory representation of the database that SQLite 8795** is currently using for that database, or NULL if the no such contiguous 8796** memory representation of the database exists. A contiguous memory 8797** representation of the database will usually only exist if there has 8798** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 8799** values of D and S. 8800** The size of the database is written into *P even if the 8801** SQLITE_SERIALIZE_NOCOPY bit is set but no contigious copy 8802** of the database exists. 8803** 8804** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 8805** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 8806** allocation error occurs. 8807** 8808** This interface is only available if SQLite is compiled with the 8809** [SQLITE_ENABLE_DESERIALIZE] option. 8810*/ 8811unsigned char *sqlite3_serialize( 8812 sqlite3 *db, /* The database connection */ 8813 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 8814 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 8815 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 8816); 8817 8818/* 8819** CAPI3REF: Flags for sqlite3_serialize 8820** 8821** Zero or more of the following constants can be OR-ed together for 8822** the F argument to [sqlite3_serialize(D,S,P,F)]. 8823** 8824** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 8825** a pointer to contiguous in-memory database that it is currently using, 8826** without making a copy of the database. If SQLite is not currently using 8827** a contiguous in-memory database, then this option causes 8828** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 8829** using a contiguous in-memory database if it has been initialized by a 8830** prior call to [sqlite3_deserialize()]. 8831*/ 8832#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 8833 8834/* 8835** CAPI3REF: Deserialize a database 8836** 8837** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 8838** [database connection] D to disconnect from database S and then 8839** reopen S as an in-memory database based on the serialization contained 8840** in P. The serialized database P is N bytes in size. M is the size of 8841** the buffer P, which might be larger than N. If M is larger than N, and 8842** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 8843** permitted to add content to the in-memory database as long as the total 8844** size does not exceed M bytes. 8845** 8846** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 8847** invoke sqlite3_free() on the serialization buffer when the database 8848** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 8849** SQLite will try to increase the buffer size using sqlite3_realloc64() 8850** if writes on the database cause it to grow larger than M bytes. 8851** 8852** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 8853** database is currently in a read transaction or is involved in a backup 8854** operation. 8855** 8856** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 8857** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 8858** [sqlite3_free()] is invoked on argument P prior to returning. 8859** 8860** This interface is only available if SQLite is compiled with the 8861** [SQLITE_ENABLE_DESERIALIZE] option. 8862*/ 8863int sqlite3_deserialize( 8864 sqlite3 *db, /* The database connection */ 8865 const char *zSchema, /* Which DB to reopen with the deserialization */ 8866 unsigned char *pData, /* The serialized database content */ 8867 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 8868 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 8869 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 8870); 8871 8872/* 8873** CAPI3REF: Flags for sqlite3_deserialize() 8874** 8875** The following are allowed values for 6th argument (the F argument) to 8876** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 8877** 8878** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 8879** in the P argument is held in memory obtained from [sqlite3_malloc64()] 8880** and that SQLite should take ownership of this memory and automatically 8881** free it when it has finished using it. Without this flag, the caller 8882** is resposible for freeing any dynamically allocated memory. 8883** 8884** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 8885** grow the size of the database using calls to [sqlite3_realloc64()]. This 8886** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 8887** Without this flag, the deserialized database cannot increase in size beyond 8888** the number of bytes specified by the M parameter. 8889** 8890** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 8891** should be treated as read-only. 8892*/ 8893#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 8894#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 8895#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 8896 8897/* 8898** Undo the hack that converts floating point types to integer for 8899** builds on processors without floating point support. 8900*/ 8901#ifdef SQLITE_OMIT_FLOATING_POINT 8902# undef double 8903#endif 8904 8905#ifdef __cplusplus 8906} /* End of the 'extern "C"' block */ 8907#endif 8908#endif /* SQLITE3_H */ 8909