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#define SQLITE_FCNTL_LAST 34 /* Last value */ 1109 1110/* deprecated names */ 1111#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1112#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1113#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1114 1115 1116/* 1117** CAPI3REF: Mutex Handle 1118** 1119** The mutex module within SQLite defines [sqlite3_mutex] to be an 1120** abstract type for a mutex object. The SQLite core never looks 1121** at the internal representation of an [sqlite3_mutex]. It only 1122** deals with pointers to the [sqlite3_mutex] object. 1123** 1124** Mutexes are created using [sqlite3_mutex_alloc()]. 1125*/ 1126typedef struct sqlite3_mutex sqlite3_mutex; 1127 1128/* 1129** CAPI3REF: Loadable Extension Thunk 1130** 1131** A pointer to the opaque sqlite3_api_routines structure is passed as 1132** the third parameter to entry points of [loadable extensions]. This 1133** structure must be typedefed in order to work around compiler warnings 1134** on some platforms. 1135*/ 1136typedef struct sqlite3_api_routines sqlite3_api_routines; 1137 1138/* 1139** CAPI3REF: OS Interface Object 1140** 1141** An instance of the sqlite3_vfs object defines the interface between 1142** the SQLite core and the underlying operating system. The "vfs" 1143** in the name of the object stands for "virtual file system". See 1144** the [VFS | VFS documentation] for further information. 1145** 1146** The VFS interface is sometimes extended by adding new methods onto 1147** the end. Each time such an extension occurs, the iVersion field 1148** is incremented. The iVersion value started out as 1 in 1149** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1150** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1151** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1152** may be appended to the sqlite3_vfs object and the iVersion value 1153** may increase again in future versions of SQLite. 1154** Note that the structure 1155** of the sqlite3_vfs object changes in the transition from 1156** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1157** and yet the iVersion field was not modified. 1158** 1159** The szOsFile field is the size of the subclassed [sqlite3_file] 1160** structure used by this VFS. mxPathname is the maximum length of 1161** a pathname in this VFS. 1162** 1163** Registered sqlite3_vfs objects are kept on a linked list formed by 1164** the pNext pointer. The [sqlite3_vfs_register()] 1165** and [sqlite3_vfs_unregister()] interfaces manage this list 1166** in a thread-safe way. The [sqlite3_vfs_find()] interface 1167** searches the list. Neither the application code nor the VFS 1168** implementation should use the pNext pointer. 1169** 1170** The pNext field is the only field in the sqlite3_vfs 1171** structure that SQLite will ever modify. SQLite will only access 1172** or modify this field while holding a particular static mutex. 1173** The application should never modify anything within the sqlite3_vfs 1174** object once the object has been registered. 1175** 1176** The zName field holds the name of the VFS module. The name must 1177** be unique across all VFS modules. 1178** 1179** [[sqlite3_vfs.xOpen]] 1180** ^SQLite guarantees that the zFilename parameter to xOpen 1181** is either a NULL pointer or string obtained 1182** from xFullPathname() with an optional suffix added. 1183** ^If a suffix is added to the zFilename parameter, it will 1184** consist of a single "-" character followed by no more than 1185** 11 alphanumeric and/or "-" characters. 1186** ^SQLite further guarantees that 1187** the string will be valid and unchanged until xClose() is 1188** called. Because of the previous sentence, 1189** the [sqlite3_file] can safely store a pointer to the 1190** filename if it needs to remember the filename for some reason. 1191** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1192** must invent its own temporary name for the file. ^Whenever the 1193** xFilename parameter is NULL it will also be the case that the 1194** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1195** 1196** The flags argument to xOpen() includes all bits set in 1197** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1198** or [sqlite3_open16()] is used, then flags includes at least 1199** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1200** If xOpen() opens a file read-only then it sets *pOutFlags to 1201** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1202** 1203** ^(SQLite will also add one of the following flags to the xOpen() 1204** call, depending on the object being opened: 1205** 1206** <ul> 1207** <li> [SQLITE_OPEN_MAIN_DB] 1208** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1209** <li> [SQLITE_OPEN_TEMP_DB] 1210** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1211** <li> [SQLITE_OPEN_TRANSIENT_DB] 1212** <li> [SQLITE_OPEN_SUBJOURNAL] 1213** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1214** <li> [SQLITE_OPEN_WAL] 1215** </ul>)^ 1216** 1217** The file I/O implementation can use the object type flags to 1218** change the way it deals with files. For example, an application 1219** that does not care about crash recovery or rollback might make 1220** the open of a journal file a no-op. Writes to this journal would 1221** also be no-ops, and any attempt to read the journal would return 1222** SQLITE_IOERR. Or the implementation might recognize that a database 1223** file will be doing page-aligned sector reads and writes in a random 1224** order and set up its I/O subsystem accordingly. 1225** 1226** SQLite might also add one of the following flags to the xOpen method: 1227** 1228** <ul> 1229** <li> [SQLITE_OPEN_DELETEONCLOSE] 1230** <li> [SQLITE_OPEN_EXCLUSIVE] 1231** </ul> 1232** 1233** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1234** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1235** will be set for TEMP databases and their journals, transient 1236** databases, and subjournals. 1237** 1238** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1239** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1240** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1241** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1242** SQLITE_OPEN_CREATE, is used to indicate that file should always 1243** be created, and that it is an error if it already exists. 1244** It is <i>not</i> used to indicate the file should be opened 1245** for exclusive access. 1246** 1247** ^At least szOsFile bytes of memory are allocated by SQLite 1248** to hold the [sqlite3_file] structure passed as the third 1249** argument to xOpen. The xOpen method does not have to 1250** allocate the structure; it should just fill it in. Note that 1251** the xOpen method must set the sqlite3_file.pMethods to either 1252** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1253** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1254** element will be valid after xOpen returns regardless of the success 1255** or failure of the xOpen call. 1256** 1257** [[sqlite3_vfs.xAccess]] 1258** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1259** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1260** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1261** to test whether a file is at least readable. The file can be a 1262** directory. 1263** 1264** ^SQLite will always allocate at least mxPathname+1 bytes for the 1265** output buffer xFullPathname. The exact size of the output buffer 1266** is also passed as a parameter to both methods. If the output buffer 1267** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1268** handled as a fatal error by SQLite, vfs implementations should endeavor 1269** to prevent this by setting mxPathname to a sufficiently large value. 1270** 1271** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1272** interfaces are not strictly a part of the filesystem, but they are 1273** included in the VFS structure for completeness. 1274** The xRandomness() function attempts to return nBytes bytes 1275** of good-quality randomness into zOut. The return value is 1276** the actual number of bytes of randomness obtained. 1277** The xSleep() method causes the calling thread to sleep for at 1278** least the number of microseconds given. ^The xCurrentTime() 1279** method returns a Julian Day Number for the current date and time as 1280** a floating point value. 1281** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1282** Day Number multiplied by 86400000 (the number of milliseconds in 1283** a 24-hour day). 1284** ^SQLite will use the xCurrentTimeInt64() method to get the current 1285** date and time if that method is available (if iVersion is 2 or 1286** greater and the function pointer is not NULL) and will fall back 1287** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1288** 1289** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1290** are not used by the SQLite core. These optional interfaces are provided 1291** by some VFSes to facilitate testing of the VFS code. By overriding 1292** system calls with functions under its control, a test program can 1293** simulate faults and error conditions that would otherwise be difficult 1294** or impossible to induce. The set of system calls that can be overridden 1295** varies from one VFS to another, and from one version of the same VFS to the 1296** next. Applications that use these interfaces must be prepared for any 1297** or all of these interfaces to be NULL or for their behavior to change 1298** from one release to the next. Applications must not attempt to access 1299** any of these methods if the iVersion of the VFS is less than 3. 1300*/ 1301typedef struct sqlite3_vfs sqlite3_vfs; 1302typedef void (*sqlite3_syscall_ptr)(void); 1303struct sqlite3_vfs { 1304 int iVersion; /* Structure version number (currently 3) */ 1305 int szOsFile; /* Size of subclassed sqlite3_file */ 1306 int mxPathname; /* Maximum file pathname length */ 1307 sqlite3_vfs *pNext; /* Next registered VFS */ 1308 const char *zName; /* Name of this virtual file system */ 1309 void *pAppData; /* Pointer to application-specific data */ 1310 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1311 int flags, int *pOutFlags); 1312 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1313 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1314 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1315 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1316 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1317 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1318 void (*xDlClose)(sqlite3_vfs*, void*); 1319 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1320 int (*xSleep)(sqlite3_vfs*, int microseconds); 1321 int (*xCurrentTime)(sqlite3_vfs*, double*); 1322 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1323 /* 1324 ** The methods above are in version 1 of the sqlite_vfs object 1325 ** definition. Those that follow are added in version 2 or later 1326 */ 1327 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1328 /* 1329 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1330 ** Those below are for version 3 and greater. 1331 */ 1332 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1333 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1334 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1335 /* 1336 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1337 ** New fields may be appended in future versions. The iVersion 1338 ** value will increment whenever this happens. 1339 */ 1340}; 1341 1342/* 1343** CAPI3REF: Flags for the xAccess VFS method 1344** 1345** These integer constants can be used as the third parameter to 1346** the xAccess method of an [sqlite3_vfs] object. They determine 1347** what kind of permissions the xAccess method is looking for. 1348** With SQLITE_ACCESS_EXISTS, the xAccess method 1349** simply checks whether the file exists. 1350** With SQLITE_ACCESS_READWRITE, the xAccess method 1351** checks whether the named directory is both readable and writable 1352** (in other words, if files can be added, removed, and renamed within 1353** the directory). 1354** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1355** [temp_store_directory pragma], though this could change in a future 1356** release of SQLite. 1357** With SQLITE_ACCESS_READ, the xAccess method 1358** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1359** currently unused, though it might be used in a future release of 1360** SQLite. 1361*/ 1362#define SQLITE_ACCESS_EXISTS 0 1363#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1364#define SQLITE_ACCESS_READ 2 /* Unused */ 1365 1366/* 1367** CAPI3REF: Flags for the xShmLock VFS method 1368** 1369** These integer constants define the various locking operations 1370** allowed by the xShmLock method of [sqlite3_io_methods]. The 1371** following are the only legal combinations of flags to the 1372** xShmLock method: 1373** 1374** <ul> 1375** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1376** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1377** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1378** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1379** </ul> 1380** 1381** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1382** was given on the corresponding lock. 1383** 1384** The xShmLock method can transition between unlocked and SHARED or 1385** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1386** and EXCLUSIVE. 1387*/ 1388#define SQLITE_SHM_UNLOCK 1 1389#define SQLITE_SHM_LOCK 2 1390#define SQLITE_SHM_SHARED 4 1391#define SQLITE_SHM_EXCLUSIVE 8 1392 1393/* 1394** CAPI3REF: Maximum xShmLock index 1395** 1396** The xShmLock method on [sqlite3_io_methods] may use values 1397** between 0 and this upper bound as its "offset" argument. 1398** The SQLite core will never attempt to acquire or release a 1399** lock outside of this range 1400*/ 1401#define SQLITE_SHM_NLOCK 8 1402 1403 1404/* 1405** CAPI3REF: Initialize The SQLite Library 1406** 1407** ^The sqlite3_initialize() routine initializes the 1408** SQLite library. ^The sqlite3_shutdown() routine 1409** deallocates any resources that were allocated by sqlite3_initialize(). 1410** These routines are designed to aid in process initialization and 1411** shutdown on embedded systems. Workstation applications using 1412** SQLite normally do not need to invoke either of these routines. 1413** 1414** A call to sqlite3_initialize() is an "effective" call if it is 1415** the first time sqlite3_initialize() is invoked during the lifetime of 1416** the process, or if it is the first time sqlite3_initialize() is invoked 1417** following a call to sqlite3_shutdown(). ^(Only an effective call 1418** of sqlite3_initialize() does any initialization. All other calls 1419** are harmless no-ops.)^ 1420** 1421** A call to sqlite3_shutdown() is an "effective" call if it is the first 1422** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1423** an effective call to sqlite3_shutdown() does any deinitialization. 1424** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1425** 1426** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1427** is not. The sqlite3_shutdown() interface must only be called from a 1428** single thread. All open [database connections] must be closed and all 1429** other SQLite resources must be deallocated prior to invoking 1430** sqlite3_shutdown(). 1431** 1432** Among other things, ^sqlite3_initialize() will invoke 1433** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1434** will invoke sqlite3_os_end(). 1435** 1436** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1437** ^If for some reason, sqlite3_initialize() is unable to initialize 1438** the library (perhaps it is unable to allocate a needed resource such 1439** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1440** 1441** ^The sqlite3_initialize() routine is called internally by many other 1442** SQLite interfaces so that an application usually does not need to 1443** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1444** calls sqlite3_initialize() so the SQLite library will be automatically 1445** initialized when [sqlite3_open()] is called if it has not be initialized 1446** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1447** compile-time option, then the automatic calls to sqlite3_initialize() 1448** are omitted and the application must call sqlite3_initialize() directly 1449** prior to using any other SQLite interface. For maximum portability, 1450** it is recommended that applications always invoke sqlite3_initialize() 1451** directly prior to using any other SQLite interface. Future releases 1452** of SQLite may require this. In other words, the behavior exhibited 1453** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1454** default behavior in some future release of SQLite. 1455** 1456** The sqlite3_os_init() routine does operating-system specific 1457** initialization of the SQLite library. The sqlite3_os_end() 1458** routine undoes the effect of sqlite3_os_init(). Typical tasks 1459** performed by these routines include allocation or deallocation 1460** of static resources, initialization of global variables, 1461** setting up a default [sqlite3_vfs] module, or setting up 1462** a default configuration using [sqlite3_config()]. 1463** 1464** The application should never invoke either sqlite3_os_init() 1465** or sqlite3_os_end() directly. The application should only invoke 1466** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1467** interface is called automatically by sqlite3_initialize() and 1468** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1469** implementations for sqlite3_os_init() and sqlite3_os_end() 1470** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1471** When [custom builds | built for other platforms] 1472** (using the [SQLITE_OS_OTHER=1] compile-time 1473** option) the application must supply a suitable implementation for 1474** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1475** implementation of sqlite3_os_init() or sqlite3_os_end() 1476** must return [SQLITE_OK] on success and some other [error code] upon 1477** failure. 1478*/ 1479int sqlite3_initialize(void); 1480int sqlite3_shutdown(void); 1481int sqlite3_os_init(void); 1482int sqlite3_os_end(void); 1483 1484/* 1485** CAPI3REF: Configuring The SQLite Library 1486** 1487** The sqlite3_config() interface is used to make global configuration 1488** changes to SQLite in order to tune SQLite to the specific needs of 1489** the application. The default configuration is recommended for most 1490** applications and so this routine is usually not necessary. It is 1491** provided to support rare applications with unusual needs. 1492** 1493** <b>The sqlite3_config() interface is not threadsafe. The application 1494** must ensure that no other SQLite interfaces are invoked by other 1495** threads while sqlite3_config() is running.</b> 1496** 1497** The sqlite3_config() interface 1498** may only be invoked prior to library initialization using 1499** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1500** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1501** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1502** Note, however, that ^sqlite3_config() can be called as part of the 1503** implementation of an application-defined [sqlite3_os_init()]. 1504** 1505** The first argument to sqlite3_config() is an integer 1506** [configuration option] that determines 1507** what property of SQLite is to be configured. Subsequent arguments 1508** vary depending on the [configuration option] 1509** in the first argument. 1510** 1511** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1512** ^If the option is unknown or SQLite is unable to set the option 1513** then this routine returns a non-zero [error code]. 1514*/ 1515int sqlite3_config(int, ...); 1516 1517/* 1518** CAPI3REF: Configure database connections 1519** METHOD: sqlite3 1520** 1521** The sqlite3_db_config() interface is used to make configuration 1522** changes to a [database connection]. The interface is similar to 1523** [sqlite3_config()] except that the changes apply to a single 1524** [database connection] (specified in the first argument). 1525** 1526** The second argument to sqlite3_db_config(D,V,...) is the 1527** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1528** that indicates what aspect of the [database connection] is being configured. 1529** Subsequent arguments vary depending on the configuration verb. 1530** 1531** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1532** the call is considered successful. 1533*/ 1534int sqlite3_db_config(sqlite3*, int op, ...); 1535 1536/* 1537** CAPI3REF: Memory Allocation Routines 1538** 1539** An instance of this object defines the interface between SQLite 1540** and low-level memory allocation routines. 1541** 1542** This object is used in only one place in the SQLite interface. 1543** A pointer to an instance of this object is the argument to 1544** [sqlite3_config()] when the configuration option is 1545** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1546** By creating an instance of this object 1547** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1548** during configuration, an application can specify an alternative 1549** memory allocation subsystem for SQLite to use for all of its 1550** dynamic memory needs. 1551** 1552** Note that SQLite comes with several [built-in memory allocators] 1553** that are perfectly adequate for the overwhelming majority of applications 1554** and that this object is only useful to a tiny minority of applications 1555** with specialized memory allocation requirements. This object is 1556** also used during testing of SQLite in order to specify an alternative 1557** memory allocator that simulates memory out-of-memory conditions in 1558** order to verify that SQLite recovers gracefully from such 1559** conditions. 1560** 1561** The xMalloc, xRealloc, and xFree methods must work like the 1562** malloc(), realloc() and free() functions from the standard C library. 1563** ^SQLite guarantees that the second argument to 1564** xRealloc is always a value returned by a prior call to xRoundup. 1565** 1566** xSize should return the allocated size of a memory allocation 1567** previously obtained from xMalloc or xRealloc. The allocated size 1568** is always at least as big as the requested size but may be larger. 1569** 1570** The xRoundup method returns what would be the allocated size of 1571** a memory allocation given a particular requested size. Most memory 1572** allocators round up memory allocations at least to the next multiple 1573** of 8. Some allocators round up to a larger multiple or to a power of 2. 1574** Every memory allocation request coming in through [sqlite3_malloc()] 1575** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1576** that causes the corresponding memory allocation to fail. 1577** 1578** The xInit method initializes the memory allocator. For example, 1579** it might allocate any require mutexes or initialize internal data 1580** structures. The xShutdown method is invoked (indirectly) by 1581** [sqlite3_shutdown()] and should deallocate any resources acquired 1582** by xInit. The pAppData pointer is used as the only parameter to 1583** xInit and xShutdown. 1584** 1585** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1586** the xInit method, so the xInit method need not be threadsafe. The 1587** xShutdown method is only called from [sqlite3_shutdown()] so it does 1588** not need to be threadsafe either. For all other methods, SQLite 1589** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1590** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1591** it is by default) and so the methods are automatically serialized. 1592** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1593** methods must be threadsafe or else make their own arrangements for 1594** serialization. 1595** 1596** SQLite will never invoke xInit() more than once without an intervening 1597** call to xShutdown(). 1598*/ 1599typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1600struct sqlite3_mem_methods { 1601 void *(*xMalloc)(int); /* Memory allocation function */ 1602 void (*xFree)(void*); /* Free a prior allocation */ 1603 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1604 int (*xSize)(void*); /* Return the size of an allocation */ 1605 int (*xRoundup)(int); /* Round up request size to allocation size */ 1606 int (*xInit)(void*); /* Initialize the memory allocator */ 1607 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1608 void *pAppData; /* Argument to xInit() and xShutdown() */ 1609}; 1610 1611/* 1612** CAPI3REF: Configuration Options 1613** KEYWORDS: {configuration option} 1614** 1615** These constants are the available integer configuration options that 1616** can be passed as the first argument to the [sqlite3_config()] interface. 1617** 1618** New configuration options may be added in future releases of SQLite. 1619** Existing configuration options might be discontinued. Applications 1620** should check the return code from [sqlite3_config()] to make sure that 1621** the call worked. The [sqlite3_config()] interface will return a 1622** non-zero [error code] if a discontinued or unsupported configuration option 1623** is invoked. 1624** 1625** <dl> 1626** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1627** <dd>There are no arguments to this option. ^This option sets the 1628** [threading mode] to Single-thread. In other words, it disables 1629** all mutexing and puts SQLite into a mode where it can only be used 1630** by a single thread. ^If SQLite is compiled with 1631** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1632** it is not possible to change the [threading mode] from its default 1633** value of Single-thread and so [sqlite3_config()] will return 1634** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1635** configuration option.</dd> 1636** 1637** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1638** <dd>There are no arguments to this option. ^This option sets the 1639** [threading mode] to Multi-thread. In other words, it disables 1640** mutexing on [database connection] and [prepared statement] objects. 1641** The application is responsible for serializing access to 1642** [database connections] and [prepared statements]. But other mutexes 1643** are enabled so that SQLite will be safe to use in a multi-threaded 1644** environment as long as no two threads attempt to use the same 1645** [database connection] at the same time. ^If SQLite is compiled with 1646** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1647** it is not possible to set the Multi-thread [threading mode] and 1648** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1649** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1650** 1651** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1652** <dd>There are no arguments to this option. ^This option sets the 1653** [threading mode] to Serialized. In other words, this option enables 1654** all mutexes including the recursive 1655** mutexes on [database connection] and [prepared statement] objects. 1656** In this mode (which is the default when SQLite is compiled with 1657** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1658** to [database connections] and [prepared statements] so that the 1659** application is free to use the same [database connection] or the 1660** same [prepared statement] in different threads at the same time. 1661** ^If SQLite is compiled with 1662** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1663** it is not possible to set the Serialized [threading mode] and 1664** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1665** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1666** 1667** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1668** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1669** a pointer to an instance of the [sqlite3_mem_methods] structure. 1670** The argument specifies 1671** alternative low-level memory allocation routines to be used in place of 1672** the memory allocation routines built into SQLite.)^ ^SQLite makes 1673** its own private copy of the content of the [sqlite3_mem_methods] structure 1674** before the [sqlite3_config()] call returns.</dd> 1675** 1676** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1677** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1678** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1679** The [sqlite3_mem_methods] 1680** structure is filled with the currently defined memory allocation routines.)^ 1681** This option can be used to overload the default memory allocation 1682** routines with a wrapper that simulations memory allocation failure or 1683** tracks memory usage, for example. </dd> 1684** 1685** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1686** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1687** type int, interpreted as a boolean, which if true provides a hint to 1688** SQLite that it should avoid large memory allocations if possible. 1689** SQLite will run faster if it is free to make large memory allocations, 1690** but some application might prefer to run slower in exchange for 1691** guarantees about memory fragmentation that are possible if large 1692** allocations are avoided. This hint is normally off. 1693** </dd> 1694** 1695** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1696** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1697** interpreted as a boolean, which enables or disables the collection of 1698** memory allocation statistics. ^(When memory allocation statistics are 1699** disabled, the following SQLite interfaces become non-operational: 1700** <ul> 1701** <li> [sqlite3_memory_used()] 1702** <li> [sqlite3_memory_highwater()] 1703** <li> [sqlite3_soft_heap_limit64()] 1704** <li> [sqlite3_status64()] 1705** </ul>)^ 1706** ^Memory allocation statistics are enabled by default unless SQLite is 1707** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1708** allocation statistics are disabled by default. 1709** </dd> 1710** 1711** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1712** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1713** </dd> 1714** 1715** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1716** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1717** that SQLite can use for the database page cache with the default page 1718** cache implementation. 1719** This configuration option is a no-op if an application-define page 1720** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1721** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1722** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1723** and the number of cache lines (N). 1724** The sz argument should be the size of the largest database page 1725** (a power of two between 512 and 65536) plus some extra bytes for each 1726** page header. ^The number of extra bytes needed by the page header 1727** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1728** ^It is harmless, apart from the wasted memory, 1729** for the sz parameter to be larger than necessary. The pMem 1730** argument must be either a NULL pointer or a pointer to an 8-byte 1731** aligned block of memory of at least sz*N bytes, otherwise 1732** subsequent behavior is undefined. 1733** ^When pMem is not NULL, SQLite will strive to use the memory provided 1734** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1735** a page cache line is larger than sz bytes or if all of the pMem buffer 1736** is exhausted. 1737** ^If pMem is NULL and N is non-zero, then each database connection 1738** does an initial bulk allocation for page cache memory 1739** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1740** of -1024*N bytes if N is negative, . ^If additional 1741** page cache memory is needed beyond what is provided by the initial 1742** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1743** additional cache line. </dd> 1744** 1745** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1746** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1747** that SQLite will use for all of its dynamic memory allocation needs 1748** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1749** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1750** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1751** [SQLITE_ERROR] if invoked otherwise. 1752** ^There are three arguments to SQLITE_CONFIG_HEAP: 1753** An 8-byte aligned pointer to the memory, 1754** the number of bytes in the memory buffer, and the minimum allocation size. 1755** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1756** to using its default memory allocator (the system malloc() implementation), 1757** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1758** memory pointer is not NULL then the alternative memory 1759** allocator is engaged to handle all of SQLites memory allocation needs. 1760** The first pointer (the memory pointer) must be aligned to an 8-byte 1761** boundary or subsequent behavior of SQLite will be undefined. 1762** The minimum allocation size is capped at 2**12. Reasonable values 1763** for the minimum allocation size are 2**5 through 2**8.</dd> 1764** 1765** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1766** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1767** pointer to an instance of the [sqlite3_mutex_methods] structure. 1768** The argument specifies alternative low-level mutex routines to be used 1769** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1770** the content of the [sqlite3_mutex_methods] structure before the call to 1771** [sqlite3_config()] returns. ^If SQLite is compiled with 1772** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1773** the entire mutexing subsystem is omitted from the build and hence calls to 1774** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1775** return [SQLITE_ERROR].</dd> 1776** 1777** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1778** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1779** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1780** [sqlite3_mutex_methods] 1781** structure is filled with the currently defined mutex routines.)^ 1782** This option can be used to overload the default mutex allocation 1783** routines with a wrapper used to track mutex usage for performance 1784** profiling or testing, for example. ^If SQLite is compiled with 1785** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1786** the entire mutexing subsystem is omitted from the build and hence calls to 1787** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1788** return [SQLITE_ERROR].</dd> 1789** 1790** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1791** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1792** the default size of lookaside memory on each [database connection]. 1793** The first argument is the 1794** size of each lookaside buffer slot and the second is the number of 1795** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1796** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1797** option to [sqlite3_db_config()] can be used to change the lookaside 1798** configuration on individual connections.)^ </dd> 1799** 1800** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1801** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1802** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1803** the interface to a custom page cache implementation.)^ 1804** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1805** 1806** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1807** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1808** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1809** the current page cache implementation into that object.)^ </dd> 1810** 1811** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1812** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1813** global [error log]. 1814** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1815** function with a call signature of void(*)(void*,int,const char*), 1816** and a pointer to void. ^If the function pointer is not NULL, it is 1817** invoked by [sqlite3_log()] to process each logging event. ^If the 1818** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1819** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1820** passed through as the first parameter to the application-defined logger 1821** function whenever that function is invoked. ^The second parameter to 1822** the logger function is a copy of the first parameter to the corresponding 1823** [sqlite3_log()] call and is intended to be a [result code] or an 1824** [extended result code]. ^The third parameter passed to the logger is 1825** log message after formatting via [sqlite3_snprintf()]. 1826** The SQLite logging interface is not reentrant; the logger function 1827** supplied by the application must not invoke any SQLite interface. 1828** In a multi-threaded application, the application-defined logger 1829** function must be threadsafe. </dd> 1830** 1831** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1832** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1833** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1834** then URI handling is globally disabled.)^ ^If URI handling is globally 1835** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1836** [sqlite3_open16()] or 1837** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1838** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1839** connection is opened. ^If it is globally disabled, filenames are 1840** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1841** database connection is opened. ^(By default, URI handling is globally 1842** disabled. The default value may be changed by compiling with the 1843** [SQLITE_USE_URI] symbol defined.)^ 1844** 1845** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1846** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1847** argument which is interpreted as a boolean in order to enable or disable 1848** the use of covering indices for full table scans in the query optimizer. 1849** ^The default setting is determined 1850** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1851** if that compile-time option is omitted. 1852** The ability to disable the use of covering indices for full table scans 1853** is because some incorrectly coded legacy applications might malfunction 1854** when the optimization is enabled. Providing the ability to 1855** disable the optimization allows the older, buggy application code to work 1856** without change even with newer versions of SQLite. 1857** 1858** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1859** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1860** <dd> These options are obsolete and should not be used by new code. 1861** They are retained for backwards compatibility but are now no-ops. 1862** </dd> 1863** 1864** [[SQLITE_CONFIG_SQLLOG]] 1865** <dt>SQLITE_CONFIG_SQLLOG 1866** <dd>This option is only available if sqlite is compiled with the 1867** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1868** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1869** The second should be of type (void*). The callback is invoked by the library 1870** in three separate circumstances, identified by the value passed as the 1871** fourth parameter. If the fourth parameter is 0, then the database connection 1872** passed as the second argument has just been opened. The third argument 1873** points to a buffer containing the name of the main database file. If the 1874** fourth parameter is 1, then the SQL statement that the third parameter 1875** points to has just been executed. Or, if the fourth parameter is 2, then 1876** the connection being passed as the second parameter is being closed. The 1877** third parameter is passed NULL In this case. An example of using this 1878** configuration option can be seen in the "test_sqllog.c" source file in 1879** the canonical SQLite source tree.</dd> 1880** 1881** [[SQLITE_CONFIG_MMAP_SIZE]] 1882** <dt>SQLITE_CONFIG_MMAP_SIZE 1883** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1884** that are the default mmap size limit (the default setting for 1885** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1886** ^The default setting can be overridden by each database connection using 1887** either the [PRAGMA mmap_size] command, or by using the 1888** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1889** will be silently truncated if necessary so that it does not exceed the 1890** compile-time maximum mmap size set by the 1891** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1892** ^If either argument to this option is negative, then that argument is 1893** changed to its compile-time default. 1894** 1895** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1896** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1897** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1898** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1899** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1900** that specifies the maximum size of the created heap. 1901** 1902** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1903** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1904** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1905** is a pointer to an integer and writes into that integer the number of extra 1906** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1907** The amount of extra space required can change depending on the compiler, 1908** target platform, and SQLite version. 1909** 1910** [[SQLITE_CONFIG_PMASZ]] 1911** <dt>SQLITE_CONFIG_PMASZ 1912** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1913** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1914** sorter to that integer. The default minimum PMA Size is set by the 1915** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1916** to help with sort operations when multithreaded sorting 1917** is enabled (using the [PRAGMA threads] command) and the amount of content 1918** to be sorted exceeds the page size times the minimum of the 1919** [PRAGMA cache_size] setting and this value. 1920** 1921** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1922** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1923** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1924** becomes the [statement journal] spill-to-disk threshold. 1925** [Statement journals] are held in memory until their size (in bytes) 1926** exceeds this threshold, at which point they are written to disk. 1927** Or if the threshold is -1, statement journals are always held 1928** exclusively in memory. 1929** Since many statement journals never become large, setting the spill 1930** threshold to a value such as 64KiB can greatly reduce the amount of 1931** I/O required to support statement rollback. 1932** The default value for this setting is controlled by the 1933** [SQLITE_STMTJRNL_SPILL] compile-time option. 1934** </dl> 1935*/ 1936#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1937#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1938#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1939#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1940#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1941#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 1942#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1943#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1944#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1945#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1946#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1947/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1948#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1949#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1950#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1951#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1952#define SQLITE_CONFIG_URI 17 /* int */ 1953#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1954#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1955#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 1956#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 1957#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 1958#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 1959#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 1960#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 1961#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 1962#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 1963 1964/* 1965** CAPI3REF: Database Connection Configuration Options 1966** 1967** These constants are the available integer configuration options that 1968** can be passed as the second argument to the [sqlite3_db_config()] interface. 1969** 1970** New configuration options may be added in future releases of SQLite. 1971** Existing configuration options might be discontinued. Applications 1972** should check the return code from [sqlite3_db_config()] to make sure that 1973** the call worked. ^The [sqlite3_db_config()] interface will return a 1974** non-zero [error code] if a discontinued or unsupported configuration option 1975** is invoked. 1976** 1977** <dl> 1978** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1979** <dd> ^This option takes three additional arguments that determine the 1980** [lookaside memory allocator] configuration for the [database connection]. 1981** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1982** pointer to a memory buffer to use for lookaside memory. 1983** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1984** may be NULL in which case SQLite will allocate the 1985** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1986** size of each lookaside buffer slot. ^The third argument is the number of 1987** slots. The size of the buffer in the first argument must be greater than 1988** or equal to the product of the second and third arguments. The buffer 1989** must be aligned to an 8-byte boundary. ^If the second argument to 1990** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1991** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1992** configuration for a database connection can only be changed when that 1993** connection is not currently using lookaside memory, or in other words 1994** when the "current value" returned by 1995** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1996** Any attempt to change the lookaside memory configuration when lookaside 1997** memory is in use leaves the configuration unchanged and returns 1998** [SQLITE_BUSY].)^</dd> 1999** 2000** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2001** <dd> ^This option is used to enable or disable the enforcement of 2002** [foreign key constraints]. There should be two additional arguments. 2003** The first argument is an integer which is 0 to disable FK enforcement, 2004** positive to enable FK enforcement or negative to leave FK enforcement 2005** unchanged. The second parameter is a pointer to an integer into which 2006** is written 0 or 1 to indicate whether FK enforcement is off or on 2007** following this call. The second parameter may be a NULL pointer, in 2008** which case the FK enforcement setting is not reported back. </dd> 2009** 2010** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2011** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2012** There should be two additional arguments. 2013** The first argument is an integer which is 0 to disable triggers, 2014** positive to enable triggers or negative to leave the setting unchanged. 2015** The second parameter is a pointer to an integer into which 2016** is written 0 or 1 to indicate whether triggers are disabled or enabled 2017** following this call. The second parameter may be a NULL pointer, in 2018** which case the trigger setting is not reported back. </dd> 2019** 2020** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2021** <dd> ^This option is used to enable or disable the two-argument 2022** version of the [fts3_tokenizer()] function which is part of the 2023** [FTS3] full-text search engine extension. 2024** There should be two additional arguments. 2025** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2026** positive to enable fts3_tokenizer() or negative to leave the setting 2027** unchanged. 2028** The second parameter is a pointer to an integer into which 2029** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2030** following this call. The second parameter may be a NULL pointer, in 2031** which case the new setting is not reported back. </dd> 2032** 2033** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2034** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2035** interface independently of the [load_extension()] SQL function. 2036** The [sqlite3_enable_load_extension()] API enables or disables both the 2037** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2038** There should be two additional arguments. 2039** When the first argument to this interface is 1, then only the C-API is 2040** enabled and the SQL function remains disabled. If the first argument to 2041** this interface is 0, then both the C-API and the SQL function are disabled. 2042** If the first argument is -1, then no changes are made to state of either the 2043** C-API or the SQL function. 2044** The second parameter is a pointer to an integer into which 2045** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2046** is disabled or enabled following this call. The second parameter may 2047** be a NULL pointer, in which case the new setting is not reported back. 2048** </dd> 2049** 2050** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2051** <dd> ^This option is used to change the name of the "main" database 2052** schema. ^The sole argument is a pointer to a constant UTF8 string 2053** which will become the new schema name in place of "main". ^SQLite 2054** does not make a copy of the new main schema name string, so the application 2055** must ensure that the argument passed into this DBCONFIG option is unchanged 2056** until after the database connection closes. 2057** </dd> 2058** 2059** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2060** <dd> Usually, when a database in wal mode is closed or detached from a 2061** database handle, SQLite checks if this will mean that there are now no 2062** connections at all to the database. If so, it performs a checkpoint 2063** operation before closing the connection. This option may be used to 2064** override this behaviour. The first parameter passed to this operation 2065** is an integer - positive to disable checkpoints-on-close, or zero (the 2066** default) to enable them, and negative to leave the setting unchanged. 2067** The second parameter is a pointer to an integer 2068** into which is written 0 or 1 to indicate whether checkpoints-on-close 2069** have been disabled - 0 if they are not disabled, 1 if they are. 2070** </dd> 2071** 2072** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2073** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2074** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2075** a single SQL query statement will always use the same algorithm regardless 2076** of values of [bound parameters].)^ The QPSG disables some query optimizations 2077** that look at the values of bound parameters, which can make some queries 2078** slower. But the QPSG has the advantage of more predictable behavior. With 2079** the QPSG active, SQLite will always use the same query plan in the field as 2080** was used during testing in the lab. 2081** The first argument to this setting is an integer which is 0 to disable 2082** the QPSG, positive to enable QPSG, or negative to leave the setting 2083** unchanged. The second parameter is a pointer to an integer into which 2084** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2085** following this call. 2086** </dd> 2087** 2088** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2089** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2090** include output for any operations performed by trigger programs. This 2091** option is used to set or clear (the default) a flag that governs this 2092** behavior. The first parameter passed to this operation is an integer - 2093** positive to enable output for trigger programs, or zero to disable it, 2094** or negative to leave the setting unchanged. 2095** The second parameter is a pointer to an integer into which is written 2096** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2097** it is not disabled, 1 if it is. 2098** </dd> 2099** </dl> 2100*/ 2101#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2102#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2103#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2104#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2105#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2106#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2107#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2108#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2109#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2110#define SQLITE_DBCONFIG_MAX 1008 /* Largest DBCONFIG */ 2111 2112/* 2113** CAPI3REF: Enable Or Disable Extended Result Codes 2114** METHOD: sqlite3 2115** 2116** ^The sqlite3_extended_result_codes() routine enables or disables the 2117** [extended result codes] feature of SQLite. ^The extended result 2118** codes are disabled by default for historical compatibility. 2119*/ 2120int sqlite3_extended_result_codes(sqlite3*, int onoff); 2121 2122/* 2123** CAPI3REF: Last Insert Rowid 2124** METHOD: sqlite3 2125** 2126** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2127** has a unique 64-bit signed 2128** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2129** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2130** names are not also used by explicitly declared columns. ^If 2131** the table has a column of type [INTEGER PRIMARY KEY] then that column 2132** is another alias for the rowid. 2133** 2134** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2135** the most recent successful [INSERT] into a rowid table or [virtual table] 2136** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2137** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2138** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2139** zero. 2140** 2141** As well as being set automatically as rows are inserted into database 2142** tables, the value returned by this function may be set explicitly by 2143** [sqlite3_set_last_insert_rowid()] 2144** 2145** Some virtual table implementations may INSERT rows into rowid tables as 2146** part of committing a transaction (e.g. to flush data accumulated in memory 2147** to disk). In this case subsequent calls to this function return the rowid 2148** associated with these internal INSERT operations, which leads to 2149** unintuitive results. Virtual table implementations that do write to rowid 2150** tables in this way can avoid this problem by restoring the original 2151** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2152** control to the user. 2153** 2154** ^(If an [INSERT] occurs within a trigger then this routine will 2155** return the [rowid] of the inserted row as long as the trigger is 2156** running. Once the trigger program ends, the value returned 2157** by this routine reverts to what it was before the trigger was fired.)^ 2158** 2159** ^An [INSERT] that fails due to a constraint violation is not a 2160** successful [INSERT] and does not change the value returned by this 2161** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2162** and INSERT OR ABORT make no changes to the return value of this 2163** routine when their insertion fails. ^(When INSERT OR REPLACE 2164** encounters a constraint violation, it does not fail. The 2165** INSERT continues to completion after deleting rows that caused 2166** the constraint problem so INSERT OR REPLACE will always change 2167** the return value of this interface.)^ 2168** 2169** ^For the purposes of this routine, an [INSERT] is considered to 2170** be successful even if it is subsequently rolled back. 2171** 2172** This function is accessible to SQL statements via the 2173** [last_insert_rowid() SQL function]. 2174** 2175** If a separate thread performs a new [INSERT] on the same 2176** database connection while the [sqlite3_last_insert_rowid()] 2177** function is running and thus changes the last insert [rowid], 2178** then the value returned by [sqlite3_last_insert_rowid()] is 2179** unpredictable and might not equal either the old or the new 2180** last insert [rowid]. 2181*/ 2182sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2183 2184/* 2185** CAPI3REF: Set the Last Insert Rowid value. 2186** METHOD: sqlite3 2187** 2188** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2189** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2190** without inserting a row into the database. 2191*/ 2192void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2193 2194/* 2195** CAPI3REF: Count The Number Of Rows Modified 2196** METHOD: sqlite3 2197** 2198** ^This function returns the number of rows modified, inserted or 2199** deleted by the most recently completed INSERT, UPDATE or DELETE 2200** statement on the database connection specified by the only parameter. 2201** ^Executing any other type of SQL statement does not modify the value 2202** returned by this function. 2203** 2204** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2205** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2206** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2207** 2208** Changes to a view that are intercepted by 2209** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2210** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2211** DELETE statement run on a view is always zero. Only changes made to real 2212** tables are counted. 2213** 2214** Things are more complicated if the sqlite3_changes() function is 2215** executed while a trigger program is running. This may happen if the 2216** program uses the [changes() SQL function], or if some other callback 2217** function invokes sqlite3_changes() directly. Essentially: 2218** 2219** <ul> 2220** <li> ^(Before entering a trigger program the value returned by 2221** sqlite3_changes() function is saved. After the trigger program 2222** has finished, the original value is restored.)^ 2223** 2224** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2225** statement sets the value returned by sqlite3_changes() 2226** upon completion as normal. Of course, this value will not include 2227** any changes performed by sub-triggers, as the sqlite3_changes() 2228** value will be saved and restored after each sub-trigger has run.)^ 2229** </ul> 2230** 2231** ^This means that if the changes() SQL function (or similar) is used 2232** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2233** returns the value as set when the calling statement began executing. 2234** ^If it is used by the second or subsequent such statement within a trigger 2235** program, the value returned reflects the number of rows modified by the 2236** previous INSERT, UPDATE or DELETE statement within the same trigger. 2237** 2238** See also the [sqlite3_total_changes()] interface, the 2239** [count_changes pragma], and the [changes() SQL function]. 2240** 2241** If a separate thread makes changes on the same database connection 2242** while [sqlite3_changes()] is running then the value returned 2243** is unpredictable and not meaningful. 2244*/ 2245int sqlite3_changes(sqlite3*); 2246 2247/* 2248** CAPI3REF: Total Number Of Rows Modified 2249** METHOD: sqlite3 2250** 2251** ^This function returns the total number of rows inserted, modified or 2252** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2253** since the database connection was opened, including those executed as 2254** part of trigger programs. ^Executing any other type of SQL statement 2255** does not affect the value returned by sqlite3_total_changes(). 2256** 2257** ^Changes made as part of [foreign key actions] are included in the 2258** count, but those made as part of REPLACE constraint resolution are 2259** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2260** are not counted. 2261** 2262** See also the [sqlite3_changes()] interface, the 2263** [count_changes pragma], and the [total_changes() SQL function]. 2264** 2265** If a separate thread makes changes on the same database connection 2266** while [sqlite3_total_changes()] is running then the value 2267** returned is unpredictable and not meaningful. 2268*/ 2269int sqlite3_total_changes(sqlite3*); 2270 2271/* 2272** CAPI3REF: Interrupt A Long-Running Query 2273** METHOD: sqlite3 2274** 2275** ^This function causes any pending database operation to abort and 2276** return at its earliest opportunity. This routine is typically 2277** called in response to a user action such as pressing "Cancel" 2278** or Ctrl-C where the user wants a long query operation to halt 2279** immediately. 2280** 2281** ^It is safe to call this routine from a thread different from the 2282** thread that is currently running the database operation. But it 2283** is not safe to call this routine with a [database connection] that 2284** is closed or might close before sqlite3_interrupt() returns. 2285** 2286** ^If an SQL operation is very nearly finished at the time when 2287** sqlite3_interrupt() is called, then it might not have an opportunity 2288** to be interrupted and might continue to completion. 2289** 2290** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2291** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2292** that is inside an explicit transaction, then the entire transaction 2293** will be rolled back automatically. 2294** 2295** ^The sqlite3_interrupt(D) call is in effect until all currently running 2296** SQL statements on [database connection] D complete. ^Any new SQL statements 2297** that are started after the sqlite3_interrupt() call and before the 2298** running statements reaches zero are interrupted as if they had been 2299** running prior to the sqlite3_interrupt() call. ^New SQL statements 2300** that are started after the running statement count reaches zero are 2301** not effected by the sqlite3_interrupt(). 2302** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2303** SQL statements is a no-op and has no effect on SQL statements 2304** that are started after the sqlite3_interrupt() call returns. 2305*/ 2306void sqlite3_interrupt(sqlite3*); 2307 2308/* 2309** CAPI3REF: Determine If An SQL Statement Is Complete 2310** 2311** These routines are useful during command-line input to determine if the 2312** currently entered text seems to form a complete SQL statement or 2313** if additional input is needed before sending the text into 2314** SQLite for parsing. ^These routines return 1 if the input string 2315** appears to be a complete SQL statement. ^A statement is judged to be 2316** complete if it ends with a semicolon token and is not a prefix of a 2317** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2318** string literals or quoted identifier names or comments are not 2319** independent tokens (they are part of the token in which they are 2320** embedded) and thus do not count as a statement terminator. ^Whitespace 2321** and comments that follow the final semicolon are ignored. 2322** 2323** ^These routines return 0 if the statement is incomplete. ^If a 2324** memory allocation fails, then SQLITE_NOMEM is returned. 2325** 2326** ^These routines do not parse the SQL statements thus 2327** will not detect syntactically incorrect SQL. 2328** 2329** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2330** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2331** automatically by sqlite3_complete16(). If that initialization fails, 2332** then the return value from sqlite3_complete16() will be non-zero 2333** regardless of whether or not the input SQL is complete.)^ 2334** 2335** The input to [sqlite3_complete()] must be a zero-terminated 2336** UTF-8 string. 2337** 2338** The input to [sqlite3_complete16()] must be a zero-terminated 2339** UTF-16 string in native byte order. 2340*/ 2341int sqlite3_complete(const char *sql); 2342int sqlite3_complete16(const void *sql); 2343 2344/* 2345** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2346** KEYWORDS: {busy-handler callback} {busy handler} 2347** METHOD: sqlite3 2348** 2349** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2350** that might be invoked with argument P whenever 2351** an attempt is made to access a database table associated with 2352** [database connection] D when another thread 2353** or process has the table locked. 2354** The sqlite3_busy_handler() interface is used to implement 2355** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2356** 2357** ^If the busy callback is NULL, then [SQLITE_BUSY] 2358** is returned immediately upon encountering the lock. ^If the busy callback 2359** is not NULL, then the callback might be invoked with two arguments. 2360** 2361** ^The first argument to the busy handler is a copy of the void* pointer which 2362** is the third argument to sqlite3_busy_handler(). ^The second argument to 2363** the busy handler callback is the number of times that the busy handler has 2364** been invoked previously for the same locking event. ^If the 2365** busy callback returns 0, then no additional attempts are made to 2366** access the database and [SQLITE_BUSY] is returned 2367** to the application. 2368** ^If the callback returns non-zero, then another attempt 2369** is made to access the database and the cycle repeats. 2370** 2371** The presence of a busy handler does not guarantee that it will be invoked 2372** when there is lock contention. ^If SQLite determines that invoking the busy 2373** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2374** to the application instead of invoking the 2375** busy handler. 2376** Consider a scenario where one process is holding a read lock that 2377** it is trying to promote to a reserved lock and 2378** a second process is holding a reserved lock that it is trying 2379** to promote to an exclusive lock. The first process cannot proceed 2380** because it is blocked by the second and the second process cannot 2381** proceed because it is blocked by the first. If both processes 2382** invoke the busy handlers, neither will make any progress. Therefore, 2383** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2384** will induce the first process to release its read lock and allow 2385** the second process to proceed. 2386** 2387** ^The default busy callback is NULL. 2388** 2389** ^(There can only be a single busy handler defined for each 2390** [database connection]. Setting a new busy handler clears any 2391** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2392** or evaluating [PRAGMA busy_timeout=N] will change the 2393** busy handler and thus clear any previously set busy handler. 2394** 2395** The busy callback should not take any actions which modify the 2396** database connection that invoked the busy handler. In other words, 2397** the busy handler is not reentrant. Any such actions 2398** result in undefined behavior. 2399** 2400** A busy handler must not close the database connection 2401** or [prepared statement] that invoked the busy handler. 2402*/ 2403int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2404 2405/* 2406** CAPI3REF: Set A Busy Timeout 2407** METHOD: sqlite3 2408** 2409** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2410** for a specified amount of time when a table is locked. ^The handler 2411** will sleep multiple times until at least "ms" milliseconds of sleeping 2412** have accumulated. ^After at least "ms" milliseconds of sleeping, 2413** the handler returns 0 which causes [sqlite3_step()] to return 2414** [SQLITE_BUSY]. 2415** 2416** ^Calling this routine with an argument less than or equal to zero 2417** turns off all busy handlers. 2418** 2419** ^(There can only be a single busy handler for a particular 2420** [database connection] at any given moment. If another busy handler 2421** was defined (using [sqlite3_busy_handler()]) prior to calling 2422** this routine, that other busy handler is cleared.)^ 2423** 2424** See also: [PRAGMA busy_timeout] 2425*/ 2426int sqlite3_busy_timeout(sqlite3*, int ms); 2427 2428/* 2429** CAPI3REF: Convenience Routines For Running Queries 2430** METHOD: sqlite3 2431** 2432** This is a legacy interface that is preserved for backwards compatibility. 2433** Use of this interface is not recommended. 2434** 2435** Definition: A <b>result table</b> is memory data structure created by the 2436** [sqlite3_get_table()] interface. A result table records the 2437** complete query results from one or more queries. 2438** 2439** The table conceptually has a number of rows and columns. But 2440** these numbers are not part of the result table itself. These 2441** numbers are obtained separately. Let N be the number of rows 2442** and M be the number of columns. 2443** 2444** A result table is an array of pointers to zero-terminated UTF-8 strings. 2445** There are (N+1)*M elements in the array. The first M pointers point 2446** to zero-terminated strings that contain the names of the columns. 2447** The remaining entries all point to query results. NULL values result 2448** in NULL pointers. All other values are in their UTF-8 zero-terminated 2449** string representation as returned by [sqlite3_column_text()]. 2450** 2451** A result table might consist of one or more memory allocations. 2452** It is not safe to pass a result table directly to [sqlite3_free()]. 2453** A result table should be deallocated using [sqlite3_free_table()]. 2454** 2455** ^(As an example of the result table format, suppose a query result 2456** is as follows: 2457** 2458** <blockquote><pre> 2459** Name | Age 2460** ----------------------- 2461** Alice | 43 2462** Bob | 28 2463** Cindy | 21 2464** </pre></blockquote> 2465** 2466** There are two column (M==2) and three rows (N==3). Thus the 2467** result table has 8 entries. Suppose the result table is stored 2468** in an array names azResult. Then azResult holds this content: 2469** 2470** <blockquote><pre> 2471** azResult[0] = "Name"; 2472** azResult[1] = "Age"; 2473** azResult[2] = "Alice"; 2474** azResult[3] = "43"; 2475** azResult[4] = "Bob"; 2476** azResult[5] = "28"; 2477** azResult[6] = "Cindy"; 2478** azResult[7] = "21"; 2479** </pre></blockquote>)^ 2480** 2481** ^The sqlite3_get_table() function evaluates one or more 2482** semicolon-separated SQL statements in the zero-terminated UTF-8 2483** string of its 2nd parameter and returns a result table to the 2484** pointer given in its 3rd parameter. 2485** 2486** After the application has finished with the result from sqlite3_get_table(), 2487** it must pass the result table pointer to sqlite3_free_table() in order to 2488** release the memory that was malloced. Because of the way the 2489** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2490** function must not try to call [sqlite3_free()] directly. Only 2491** [sqlite3_free_table()] is able to release the memory properly and safely. 2492** 2493** The sqlite3_get_table() interface is implemented as a wrapper around 2494** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2495** to any internal data structures of SQLite. It uses only the public 2496** interface defined here. As a consequence, errors that occur in the 2497** wrapper layer outside of the internal [sqlite3_exec()] call are not 2498** reflected in subsequent calls to [sqlite3_errcode()] or 2499** [sqlite3_errmsg()]. 2500*/ 2501int sqlite3_get_table( 2502 sqlite3 *db, /* An open database */ 2503 const char *zSql, /* SQL to be evaluated */ 2504 char ***pazResult, /* Results of the query */ 2505 int *pnRow, /* Number of result rows written here */ 2506 int *pnColumn, /* Number of result columns written here */ 2507 char **pzErrmsg /* Error msg written here */ 2508); 2509void sqlite3_free_table(char **result); 2510 2511/* 2512** CAPI3REF: Formatted String Printing Functions 2513** 2514** These routines are work-alikes of the "printf()" family of functions 2515** from the standard C library. 2516** These routines understand most of the common formatting options from 2517** the standard library printf() 2518** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2519** See the [built-in printf()] documentation for details. 2520** 2521** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2522** results into memory obtained from [sqlite3_malloc64()]. 2523** The strings returned by these two routines should be 2524** released by [sqlite3_free()]. ^Both routines return a 2525** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2526** memory to hold the resulting string. 2527** 2528** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2529** the standard C library. The result is written into the 2530** buffer supplied as the second parameter whose size is given by 2531** the first parameter. Note that the order of the 2532** first two parameters is reversed from snprintf().)^ This is an 2533** historical accident that cannot be fixed without breaking 2534** backwards compatibility. ^(Note also that sqlite3_snprintf() 2535** returns a pointer to its buffer instead of the number of 2536** characters actually written into the buffer.)^ We admit that 2537** the number of characters written would be a more useful return 2538** value but we cannot change the implementation of sqlite3_snprintf() 2539** now without breaking compatibility. 2540** 2541** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2542** guarantees that the buffer is always zero-terminated. ^The first 2543** parameter "n" is the total size of the buffer, including space for 2544** the zero terminator. So the longest string that can be completely 2545** written will be n-1 characters. 2546** 2547** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2548** 2549** See also: [built-in printf()], [printf() SQL function] 2550*/ 2551char *sqlite3_mprintf(const char*,...); 2552char *sqlite3_vmprintf(const char*, va_list); 2553char *sqlite3_snprintf(int,char*,const char*, ...); 2554char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2555 2556/* 2557** CAPI3REF: Memory Allocation Subsystem 2558** 2559** The SQLite core uses these three routines for all of its own 2560** internal memory allocation needs. "Core" in the previous sentence 2561** does not include operating-system specific VFS implementation. The 2562** Windows VFS uses native malloc() and free() for some operations. 2563** 2564** ^The sqlite3_malloc() routine returns a pointer to a block 2565** of memory at least N bytes in length, where N is the parameter. 2566** ^If sqlite3_malloc() is unable to obtain sufficient free 2567** memory, it returns a NULL pointer. ^If the parameter N to 2568** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2569** a NULL pointer. 2570** 2571** ^The sqlite3_malloc64(N) routine works just like 2572** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2573** of a signed 32-bit integer. 2574** 2575** ^Calling sqlite3_free() with a pointer previously returned 2576** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2577** that it might be reused. ^The sqlite3_free() routine is 2578** a no-op if is called with a NULL pointer. Passing a NULL pointer 2579** to sqlite3_free() is harmless. After being freed, memory 2580** should neither be read nor written. Even reading previously freed 2581** memory might result in a segmentation fault or other severe error. 2582** Memory corruption, a segmentation fault, or other severe error 2583** might result if sqlite3_free() is called with a non-NULL pointer that 2584** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2585** 2586** ^The sqlite3_realloc(X,N) interface attempts to resize a 2587** prior memory allocation X to be at least N bytes. 2588** ^If the X parameter to sqlite3_realloc(X,N) 2589** is a NULL pointer then its behavior is identical to calling 2590** sqlite3_malloc(N). 2591** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2592** negative then the behavior is exactly the same as calling 2593** sqlite3_free(X). 2594** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2595** of at least N bytes in size or NULL if insufficient memory is available. 2596** ^If M is the size of the prior allocation, then min(N,M) bytes 2597** of the prior allocation are copied into the beginning of buffer returned 2598** by sqlite3_realloc(X,N) and the prior allocation is freed. 2599** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2600** prior allocation is not freed. 2601** 2602** ^The sqlite3_realloc64(X,N) interfaces works the same as 2603** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2604** of a 32-bit signed integer. 2605** 2606** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2607** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2608** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2609** ^The value returned by sqlite3_msize(X) might be larger than the number 2610** of bytes requested when X was allocated. ^If X is a NULL pointer then 2611** sqlite3_msize(X) returns zero. If X points to something that is not 2612** the beginning of memory allocation, or if it points to a formerly 2613** valid memory allocation that has now been freed, then the behavior 2614** of sqlite3_msize(X) is undefined and possibly harmful. 2615** 2616** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2617** sqlite3_malloc64(), and sqlite3_realloc64() 2618** is always aligned to at least an 8 byte boundary, or to a 2619** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2620** option is used. 2621** 2622** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2623** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2624** implementation of these routines to be omitted. That capability 2625** is no longer provided. Only built-in memory allocators can be used. 2626** 2627** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2628** the system malloc() and free() directly when converting 2629** filenames between the UTF-8 encoding used by SQLite 2630** and whatever filename encoding is used by the particular Windows 2631** installation. Memory allocation errors were detected, but 2632** they were reported back as [SQLITE_CANTOPEN] or 2633** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2634** 2635** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2636** must be either NULL or else pointers obtained from a prior 2637** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2638** not yet been released. 2639** 2640** The application must not read or write any part of 2641** a block of memory after it has been released using 2642** [sqlite3_free()] or [sqlite3_realloc()]. 2643*/ 2644void *sqlite3_malloc(int); 2645void *sqlite3_malloc64(sqlite3_uint64); 2646void *sqlite3_realloc(void*, int); 2647void *sqlite3_realloc64(void*, sqlite3_uint64); 2648void sqlite3_free(void*); 2649sqlite3_uint64 sqlite3_msize(void*); 2650 2651/* 2652** CAPI3REF: Memory Allocator Statistics 2653** 2654** SQLite provides these two interfaces for reporting on the status 2655** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2656** routines, which form the built-in memory allocation subsystem. 2657** 2658** ^The [sqlite3_memory_used()] routine returns the number of bytes 2659** of memory currently outstanding (malloced but not freed). 2660** ^The [sqlite3_memory_highwater()] routine returns the maximum 2661** value of [sqlite3_memory_used()] since the high-water mark 2662** was last reset. ^The values returned by [sqlite3_memory_used()] and 2663** [sqlite3_memory_highwater()] include any overhead 2664** added by SQLite in its implementation of [sqlite3_malloc()], 2665** but not overhead added by the any underlying system library 2666** routines that [sqlite3_malloc()] may call. 2667** 2668** ^The memory high-water mark is reset to the current value of 2669** [sqlite3_memory_used()] if and only if the parameter to 2670** [sqlite3_memory_highwater()] is true. ^The value returned 2671** by [sqlite3_memory_highwater(1)] is the high-water mark 2672** prior to the reset. 2673*/ 2674sqlite3_int64 sqlite3_memory_used(void); 2675sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2676 2677/* 2678** CAPI3REF: Pseudo-Random Number Generator 2679** 2680** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2681** select random [ROWID | ROWIDs] when inserting new records into a table that 2682** already uses the largest possible [ROWID]. The PRNG is also used for 2683** the build-in random() and randomblob() SQL functions. This interface allows 2684** applications to access the same PRNG for other purposes. 2685** 2686** ^A call to this routine stores N bytes of randomness into buffer P. 2687** ^The P parameter can be a NULL pointer. 2688** 2689** ^If this routine has not been previously called or if the previous 2690** call had N less than one or a NULL pointer for P, then the PRNG is 2691** seeded using randomness obtained from the xRandomness method of 2692** the default [sqlite3_vfs] object. 2693** ^If the previous call to this routine had an N of 1 or more and a 2694** non-NULL P then the pseudo-randomness is generated 2695** internally and without recourse to the [sqlite3_vfs] xRandomness 2696** method. 2697*/ 2698void sqlite3_randomness(int N, void *P); 2699 2700/* 2701** CAPI3REF: Compile-Time Authorization Callbacks 2702** METHOD: sqlite3 2703** KEYWORDS: {authorizer callback} 2704** 2705** ^This routine registers an authorizer callback with a particular 2706** [database connection], supplied in the first argument. 2707** ^The authorizer callback is invoked as SQL statements are being compiled 2708** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2709** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2710** and [sqlite3_prepare16_v3()]. ^At various 2711** points during the compilation process, as logic is being created 2712** to perform various actions, the authorizer callback is invoked to 2713** see if those actions are allowed. ^The authorizer callback should 2714** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2715** specific action but allow the SQL statement to continue to be 2716** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2717** rejected with an error. ^If the authorizer callback returns 2718** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2719** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2720** the authorizer will fail with an error message. 2721** 2722** When the callback returns [SQLITE_OK], that means the operation 2723** requested is ok. ^When the callback returns [SQLITE_DENY], the 2724** [sqlite3_prepare_v2()] or equivalent call that triggered the 2725** authorizer will fail with an error message explaining that 2726** access is denied. 2727** 2728** ^The first parameter to the authorizer callback is a copy of the third 2729** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2730** to the callback is an integer [SQLITE_COPY | action code] that specifies 2731** the particular action to be authorized. ^The third through sixth parameters 2732** to the callback are either NULL pointers or zero-terminated strings 2733** that contain additional details about the action to be authorized. 2734** Applications must always be prepared to encounter a NULL pointer in any 2735** of the third through the sixth parameters of the authorization callback. 2736** 2737** ^If the action code is [SQLITE_READ] 2738** and the callback returns [SQLITE_IGNORE] then the 2739** [prepared statement] statement is constructed to substitute 2740** a NULL value in place of the table column that would have 2741** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2742** return can be used to deny an untrusted user access to individual 2743** columns of a table. 2744** ^When a table is referenced by a [SELECT] but no column values are 2745** extracted from that table (for example in a query like 2746** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2747** is invoked once for that table with a column name that is an empty string. 2748** ^If the action code is [SQLITE_DELETE] and the callback returns 2749** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2750** [truncate optimization] is disabled and all rows are deleted individually. 2751** 2752** An authorizer is used when [sqlite3_prepare | preparing] 2753** SQL statements from an untrusted source, to ensure that the SQL statements 2754** do not try to access data they are not allowed to see, or that they do not 2755** try to execute malicious statements that damage the database. For 2756** example, an application may allow a user to enter arbitrary 2757** SQL queries for evaluation by a database. But the application does 2758** not want the user to be able to make arbitrary changes to the 2759** database. An authorizer could then be put in place while the 2760** user-entered SQL is being [sqlite3_prepare | prepared] that 2761** disallows everything except [SELECT] statements. 2762** 2763** Applications that need to process SQL from untrusted sources 2764** might also consider lowering resource limits using [sqlite3_limit()] 2765** and limiting database size using the [max_page_count] [PRAGMA] 2766** in addition to using an authorizer. 2767** 2768** ^(Only a single authorizer can be in place on a database connection 2769** at a time. Each call to sqlite3_set_authorizer overrides the 2770** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2771** The authorizer is disabled by default. 2772** 2773** The authorizer callback must not do anything that will modify 2774** the database connection that invoked the authorizer callback. 2775** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2776** database connections for the meaning of "modify" in this paragraph. 2777** 2778** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2779** statement might be re-prepared during [sqlite3_step()] due to a 2780** schema change. Hence, the application should ensure that the 2781** correct authorizer callback remains in place during the [sqlite3_step()]. 2782** 2783** ^Note that the authorizer callback is invoked only during 2784** [sqlite3_prepare()] or its variants. Authorization is not 2785** performed during statement evaluation in [sqlite3_step()], unless 2786** as stated in the previous paragraph, sqlite3_step() invokes 2787** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2788*/ 2789int sqlite3_set_authorizer( 2790 sqlite3*, 2791 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2792 void *pUserData 2793); 2794 2795/* 2796** CAPI3REF: Authorizer Return Codes 2797** 2798** The [sqlite3_set_authorizer | authorizer callback function] must 2799** return either [SQLITE_OK] or one of these two constants in order 2800** to signal SQLite whether or not the action is permitted. See the 2801** [sqlite3_set_authorizer | authorizer documentation] for additional 2802** information. 2803** 2804** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2805** returned from the [sqlite3_vtab_on_conflict()] interface. 2806*/ 2807#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2808#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2809 2810/* 2811** CAPI3REF: Authorizer Action Codes 2812** 2813** The [sqlite3_set_authorizer()] interface registers a callback function 2814** that is invoked to authorize certain SQL statement actions. The 2815** second parameter to the callback is an integer code that specifies 2816** what action is being authorized. These are the integer action codes that 2817** the authorizer callback may be passed. 2818** 2819** These action code values signify what kind of operation is to be 2820** authorized. The 3rd and 4th parameters to the authorization 2821** callback function will be parameters or NULL depending on which of these 2822** codes is used as the second parameter. ^(The 5th parameter to the 2823** authorizer callback is the name of the database ("main", "temp", 2824** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2825** is the name of the inner-most trigger or view that is responsible for 2826** the access attempt or NULL if this access attempt is directly from 2827** top-level SQL code. 2828*/ 2829/******************************************* 3rd ************ 4th ***********/ 2830#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2831#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2832#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2833#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2834#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2835#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2836#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2837#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2838#define SQLITE_DELETE 9 /* Table Name NULL */ 2839#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2840#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2841#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2842#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2843#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2844#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2845#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2846#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2847#define SQLITE_INSERT 18 /* Table Name NULL */ 2848#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2849#define SQLITE_READ 20 /* Table Name Column Name */ 2850#define SQLITE_SELECT 21 /* NULL NULL */ 2851#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2852#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2853#define SQLITE_ATTACH 24 /* Filename NULL */ 2854#define SQLITE_DETACH 25 /* Database Name NULL */ 2855#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2856#define SQLITE_REINDEX 27 /* Index Name NULL */ 2857#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2858#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2859#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2860#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2861#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2862#define SQLITE_COPY 0 /* No longer used */ 2863#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2864 2865/* 2866** CAPI3REF: Tracing And Profiling Functions 2867** METHOD: sqlite3 2868** 2869** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2870** instead of the routines described here. 2871** 2872** These routines register callback functions that can be used for 2873** tracing and profiling the execution of SQL statements. 2874** 2875** ^The callback function registered by sqlite3_trace() is invoked at 2876** various times when an SQL statement is being run by [sqlite3_step()]. 2877** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2878** SQL statement text as the statement first begins executing. 2879** ^(Additional sqlite3_trace() callbacks might occur 2880** as each triggered subprogram is entered. The callbacks for triggers 2881** contain a UTF-8 SQL comment that identifies the trigger.)^ 2882** 2883** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 2884** the length of [bound parameter] expansion in the output of sqlite3_trace(). 2885** 2886** ^The callback function registered by sqlite3_profile() is invoked 2887** as each SQL statement finishes. ^The profile callback contains 2888** the original statement text and an estimate of wall-clock time 2889** of how long that statement took to run. ^The profile callback 2890** time is in units of nanoseconds, however the current implementation 2891** is only capable of millisecond resolution so the six least significant 2892** digits in the time are meaningless. Future versions of SQLite 2893** might provide greater resolution on the profiler callback. The 2894** sqlite3_profile() function is considered experimental and is 2895** subject to change in future versions of SQLite. 2896*/ 2897SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 2898 void(*xTrace)(void*,const char*), void*); 2899SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 2900 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2901 2902/* 2903** CAPI3REF: SQL Trace Event Codes 2904** KEYWORDS: SQLITE_TRACE 2905** 2906** These constants identify classes of events that can be monitored 2907** using the [sqlite3_trace_v2()] tracing logic. The M argument 2908** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 2909** the following constants. ^The first argument to the trace callback 2910** is one of the following constants. 2911** 2912** New tracing constants may be added in future releases. 2913** 2914** ^A trace callback has four arguments: xCallback(T,C,P,X). 2915** ^The T argument is one of the integer type codes above. 2916** ^The C argument is a copy of the context pointer passed in as the 2917** fourth argument to [sqlite3_trace_v2()]. 2918** The P and X arguments are pointers whose meanings depend on T. 2919** 2920** <dl> 2921** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 2922** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 2923** first begins running and possibly at other times during the 2924** execution of the prepared statement, such as at the start of each 2925** trigger subprogram. ^The P argument is a pointer to the 2926** [prepared statement]. ^The X argument is a pointer to a string which 2927** is the unexpanded SQL text of the prepared statement or an SQL comment 2928** that indicates the invocation of a trigger. ^The callback can compute 2929** the same text that would have been returned by the legacy [sqlite3_trace()] 2930** interface by using the X argument when X begins with "--" and invoking 2931** [sqlite3_expanded_sql(P)] otherwise. 2932** 2933** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 2934** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 2935** information as is provided by the [sqlite3_profile()] callback. 2936** ^The P argument is a pointer to the [prepared statement] and the 2937** X argument points to a 64-bit integer which is the estimated of 2938** the number of nanosecond that the prepared statement took to run. 2939** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 2940** 2941** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 2942** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 2943** statement generates a single row of result. 2944** ^The P argument is a pointer to the [prepared statement] and the 2945** X argument is unused. 2946** 2947** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 2948** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 2949** connection closes. 2950** ^The P argument is a pointer to the [database connection] object 2951** and the X argument is unused. 2952** </dl> 2953*/ 2954#define SQLITE_TRACE_STMT 0x01 2955#define SQLITE_TRACE_PROFILE 0x02 2956#define SQLITE_TRACE_ROW 0x04 2957#define SQLITE_TRACE_CLOSE 0x08 2958 2959/* 2960** CAPI3REF: SQL Trace Hook 2961** METHOD: sqlite3 2962** 2963** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 2964** function X against [database connection] D, using property mask M 2965** and context pointer P. ^If the X callback is 2966** NULL or if the M mask is zero, then tracing is disabled. The 2967** M argument should be the bitwise OR-ed combination of 2968** zero or more [SQLITE_TRACE] constants. 2969** 2970** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 2971** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 2972** 2973** ^The X callback is invoked whenever any of the events identified by 2974** mask M occur. ^The integer return value from the callback is currently 2975** ignored, though this may change in future releases. Callback 2976** implementations should return zero to ensure future compatibility. 2977** 2978** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 2979** ^The T argument is one of the [SQLITE_TRACE] 2980** constants to indicate why the callback was invoked. 2981** ^The C argument is a copy of the context pointer. 2982** The P and X arguments are pointers whose meanings depend on T. 2983** 2984** The sqlite3_trace_v2() interface is intended to replace the legacy 2985** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 2986** are deprecated. 2987*/ 2988int sqlite3_trace_v2( 2989 sqlite3*, 2990 unsigned uMask, 2991 int(*xCallback)(unsigned,void*,void*,void*), 2992 void *pCtx 2993); 2994 2995/* 2996** CAPI3REF: Query Progress Callbacks 2997** METHOD: sqlite3 2998** 2999** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3000** function X to be invoked periodically during long running calls to 3001** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3002** database connection D. An example use for this 3003** interface is to keep a GUI updated during a large query. 3004** 3005** ^The parameter P is passed through as the only parameter to the 3006** callback function X. ^The parameter N is the approximate number of 3007** [virtual machine instructions] that are evaluated between successive 3008** invocations of the callback X. ^If N is less than one then the progress 3009** handler is disabled. 3010** 3011** ^Only a single progress handler may be defined at one time per 3012** [database connection]; setting a new progress handler cancels the 3013** old one. ^Setting parameter X to NULL disables the progress handler. 3014** ^The progress handler is also disabled by setting N to a value less 3015** than 1. 3016** 3017** ^If the progress callback returns non-zero, the operation is 3018** interrupted. This feature can be used to implement a 3019** "Cancel" button on a GUI progress dialog box. 3020** 3021** The progress handler callback must not do anything that will modify 3022** the database connection that invoked the progress handler. 3023** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3024** database connections for the meaning of "modify" in this paragraph. 3025** 3026*/ 3027void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3028 3029/* 3030** CAPI3REF: Opening A New Database Connection 3031** CONSTRUCTOR: sqlite3 3032** 3033** ^These routines open an SQLite database file as specified by the 3034** filename argument. ^The filename argument is interpreted as UTF-8 for 3035** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3036** order for sqlite3_open16(). ^(A [database connection] handle is usually 3037** returned in *ppDb, even if an error occurs. The only exception is that 3038** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3039** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3040** object.)^ ^(If the database is opened (and/or created) successfully, then 3041** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3042** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3043** an English language description of the error following a failure of any 3044** of the sqlite3_open() routines. 3045** 3046** ^The default encoding will be UTF-8 for databases created using 3047** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3048** created using sqlite3_open16() will be UTF-16 in the native byte order. 3049** 3050** Whether or not an error occurs when it is opened, resources 3051** associated with the [database connection] handle should be released by 3052** passing it to [sqlite3_close()] when it is no longer required. 3053** 3054** The sqlite3_open_v2() interface works like sqlite3_open() 3055** except that it accepts two additional parameters for additional control 3056** over the new database connection. ^(The flags parameter to 3057** sqlite3_open_v2() can take one of 3058** the following three values, optionally combined with the 3059** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3060** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3061** 3062** <dl> 3063** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3064** <dd>The database is opened in read-only mode. If the database does not 3065** already exist, an error is returned.</dd>)^ 3066** 3067** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3068** <dd>The database is opened for reading and writing if possible, or reading 3069** only if the file is write protected by the operating system. In either 3070** case the database must already exist, otherwise an error is returned.</dd>)^ 3071** 3072** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3073** <dd>The database is opened for reading and writing, and is created if 3074** it does not already exist. This is the behavior that is always used for 3075** sqlite3_open() and sqlite3_open16().</dd>)^ 3076** </dl> 3077** 3078** If the 3rd parameter to sqlite3_open_v2() is not one of the 3079** combinations shown above optionally combined with other 3080** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3081** then the behavior is undefined. 3082** 3083** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3084** opens in the multi-thread [threading mode] as long as the single-thread 3085** mode has not been set at compile-time or start-time. ^If the 3086** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3087** in the serialized [threading mode] unless single-thread was 3088** previously selected at compile-time or start-time. 3089** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3090** eligible to use [shared cache mode], regardless of whether or not shared 3091** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3092** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3093** participate in [shared cache mode] even if it is enabled. 3094** 3095** ^The fourth parameter to sqlite3_open_v2() is the name of the 3096** [sqlite3_vfs] object that defines the operating system interface that 3097** the new database connection should use. ^If the fourth parameter is 3098** a NULL pointer then the default [sqlite3_vfs] object is used. 3099** 3100** ^If the filename is ":memory:", then a private, temporary in-memory database 3101** is created for the connection. ^This in-memory database will vanish when 3102** the database connection is closed. Future versions of SQLite might 3103** make use of additional special filenames that begin with the ":" character. 3104** It is recommended that when a database filename actually does begin with 3105** a ":" character you should prefix the filename with a pathname such as 3106** "./" to avoid ambiguity. 3107** 3108** ^If the filename is an empty string, then a private, temporary 3109** on-disk database will be created. ^This private database will be 3110** automatically deleted as soon as the database connection is closed. 3111** 3112** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3113** 3114** ^If [URI filename] interpretation is enabled, and the filename argument 3115** begins with "file:", then the filename is interpreted as a URI. ^URI 3116** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3117** set in the third argument to sqlite3_open_v2(), or if it has 3118** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3119** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3120** URI filename interpretation is turned off 3121** by default, but future releases of SQLite might enable URI filename 3122** interpretation by default. See "[URI filenames]" for additional 3123** information. 3124** 3125** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3126** authority, then it must be either an empty string or the string 3127** "localhost". ^If the authority is not an empty string or "localhost", an 3128** error is returned to the caller. ^The fragment component of a URI, if 3129** present, is ignored. 3130** 3131** ^SQLite uses the path component of the URI as the name of the disk file 3132** which contains the database. ^If the path begins with a '/' character, 3133** then it is interpreted as an absolute path. ^If the path does not begin 3134** with a '/' (meaning that the authority section is omitted from the URI) 3135** then the path is interpreted as a relative path. 3136** ^(On windows, the first component of an absolute path 3137** is a drive specification (e.g. "C:").)^ 3138** 3139** [[core URI query parameters]] 3140** The query component of a URI may contain parameters that are interpreted 3141** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3142** SQLite and its built-in [VFSes] interpret the 3143** following query parameters: 3144** 3145** <ul> 3146** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3147** a VFS object that provides the operating system interface that should 3148** be used to access the database file on disk. ^If this option is set to 3149** an empty string the default VFS object is used. ^Specifying an unknown 3150** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3151** present, then the VFS specified by the option takes precedence over 3152** the value passed as the fourth parameter to sqlite3_open_v2(). 3153** 3154** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3155** "rwc", or "memory". Attempting to set it to any other value is 3156** an error)^. 3157** ^If "ro" is specified, then the database is opened for read-only 3158** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3159** third argument to sqlite3_open_v2(). ^If the mode option is set to 3160** "rw", then the database is opened for read-write (but not create) 3161** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3162** been set. ^Value "rwc" is equivalent to setting both 3163** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3164** set to "memory" then a pure [in-memory database] that never reads 3165** or writes from disk is used. ^It is an error to specify a value for 3166** the mode parameter that is less restrictive than that specified by 3167** the flags passed in the third parameter to sqlite3_open_v2(). 3168** 3169** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3170** "private". ^Setting it to "shared" is equivalent to setting the 3171** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3172** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3173** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3174** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3175** a URI filename, its value overrides any behavior requested by setting 3176** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3177** 3178** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3179** [powersafe overwrite] property does or does not apply to the 3180** storage media on which the database file resides. 3181** 3182** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3183** which if set disables file locking in rollback journal modes. This 3184** is useful for accessing a database on a filesystem that does not 3185** support locking. Caution: Database corruption might result if two 3186** or more processes write to the same database and any one of those 3187** processes uses nolock=1. 3188** 3189** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3190** parameter that indicates that the database file is stored on 3191** read-only media. ^When immutable is set, SQLite assumes that the 3192** database file cannot be changed, even by a process with higher 3193** privilege, and so the database is opened read-only and all locking 3194** and change detection is disabled. Caution: Setting the immutable 3195** property on a database file that does in fact change can result 3196** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3197** See also: [SQLITE_IOCAP_IMMUTABLE]. 3198** 3199** </ul> 3200** 3201** ^Specifying an unknown parameter in the query component of a URI is not an 3202** error. Future versions of SQLite might understand additional query 3203** parameters. See "[query parameters with special meaning to SQLite]" for 3204** additional information. 3205** 3206** [[URI filename examples]] <h3>URI filename examples</h3> 3207** 3208** <table border="1" align=center cellpadding=5> 3209** <tr><th> URI filenames <th> Results 3210** <tr><td> file:data.db <td> 3211** Open the file "data.db" in the current directory. 3212** <tr><td> file:/home/fred/data.db<br> 3213** file:///home/fred/data.db <br> 3214** file://localhost/home/fred/data.db <br> <td> 3215** Open the database file "/home/fred/data.db". 3216** <tr><td> file://darkstar/home/fred/data.db <td> 3217** An error. "darkstar" is not a recognized authority. 3218** <tr><td style="white-space:nowrap"> 3219** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3220** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3221** C:. Note that the %20 escaping in this example is not strictly 3222** necessary - space characters can be used literally 3223** in URI filenames. 3224** <tr><td> file:data.db?mode=ro&cache=private <td> 3225** Open file "data.db" in the current directory for read-only access. 3226** Regardless of whether or not shared-cache mode is enabled by 3227** default, use a private cache. 3228** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3229** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3230** that uses dot-files in place of posix advisory locking. 3231** <tr><td> file:data.db?mode=readonly <td> 3232** An error. "readonly" is not a valid option for the "mode" parameter. 3233** </table> 3234** 3235** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3236** query components of a URI. A hexadecimal escape sequence consists of a 3237** percent sign - "%" - followed by exactly two hexadecimal digits 3238** specifying an octet value. ^Before the path or query components of a 3239** URI filename are interpreted, they are encoded using UTF-8 and all 3240** hexadecimal escape sequences replaced by a single byte containing the 3241** corresponding octet. If this process generates an invalid UTF-8 encoding, 3242** the results are undefined. 3243** 3244** <b>Note to Windows users:</b> The encoding used for the filename argument 3245** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3246** codepage is currently defined. Filenames containing international 3247** characters must be converted to UTF-8 prior to passing them into 3248** sqlite3_open() or sqlite3_open_v2(). 3249** 3250** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3251** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3252** features that require the use of temporary files may fail. 3253** 3254** See also: [sqlite3_temp_directory] 3255*/ 3256int sqlite3_open( 3257 const char *filename, /* Database filename (UTF-8) */ 3258 sqlite3 **ppDb /* OUT: SQLite db handle */ 3259); 3260int sqlite3_open16( 3261 const void *filename, /* Database filename (UTF-16) */ 3262 sqlite3 **ppDb /* OUT: SQLite db handle */ 3263); 3264int sqlite3_open_v2( 3265 const char *filename, /* Database filename (UTF-8) */ 3266 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3267 int flags, /* Flags */ 3268 const char *zVfs /* Name of VFS module to use */ 3269); 3270 3271/* 3272** CAPI3REF: Obtain Values For URI Parameters 3273** 3274** These are utility routines, useful to VFS implementations, that check 3275** to see if a database file was a URI that contained a specific query 3276** parameter, and if so obtains the value of that query parameter. 3277** 3278** If F is the database filename pointer passed into the xOpen() method of 3279** a VFS implementation when the flags parameter to xOpen() has one or 3280** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3281** P is the name of the query parameter, then 3282** sqlite3_uri_parameter(F,P) returns the value of the P 3283** parameter if it exists or a NULL pointer if P does not appear as a 3284** query parameter on F. If P is a query parameter of F 3285** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3286** a pointer to an empty string. 3287** 3288** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3289** parameter and returns true (1) or false (0) according to the value 3290** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3291** value of query parameter P is one of "yes", "true", or "on" in any 3292** case or if the value begins with a non-zero number. The 3293** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3294** query parameter P is one of "no", "false", or "off" in any case or 3295** if the value begins with a numeric zero. If P is not a query 3296** parameter on F or if the value of P is does not match any of the 3297** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3298** 3299** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3300** 64-bit signed integer and returns that integer, or D if P does not 3301** exist. If the value of P is something other than an integer, then 3302** zero is returned. 3303** 3304** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3305** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3306** is not a database file pathname pointer that SQLite passed into the xOpen 3307** VFS method, then the behavior of this routine is undefined and probably 3308** undesirable. 3309*/ 3310const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3311int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3312sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3313 3314 3315/* 3316** CAPI3REF: Error Codes And Messages 3317** METHOD: sqlite3 3318** 3319** ^If the most recent sqlite3_* API call associated with 3320** [database connection] D failed, then the sqlite3_errcode(D) interface 3321** returns the numeric [result code] or [extended result code] for that 3322** API call. 3323** If the most recent API call was successful, 3324** then the return value from sqlite3_errcode() is undefined. 3325** ^The sqlite3_extended_errcode() 3326** interface is the same except that it always returns the 3327** [extended result code] even when extended result codes are 3328** disabled. 3329** 3330** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3331** text that describes the error, as either UTF-8 or UTF-16 respectively. 3332** ^(Memory to hold the error message string is managed internally. 3333** The application does not need to worry about freeing the result. 3334** However, the error string might be overwritten or deallocated by 3335** subsequent calls to other SQLite interface functions.)^ 3336** 3337** ^The sqlite3_errstr() interface returns the English-language text 3338** that describes the [result code], as UTF-8. 3339** ^(Memory to hold the error message string is managed internally 3340** and must not be freed by the application)^. 3341** 3342** When the serialized [threading mode] is in use, it might be the 3343** case that a second error occurs on a separate thread in between 3344** the time of the first error and the call to these interfaces. 3345** When that happens, the second error will be reported since these 3346** interfaces always report the most recent result. To avoid 3347** this, each thread can obtain exclusive use of the [database connection] D 3348** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3349** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3350** all calls to the interfaces listed here are completed. 3351** 3352** If an interface fails with SQLITE_MISUSE, that means the interface 3353** was invoked incorrectly by the application. In that case, the 3354** error code and message may or may not be set. 3355*/ 3356int sqlite3_errcode(sqlite3 *db); 3357int sqlite3_extended_errcode(sqlite3 *db); 3358const char *sqlite3_errmsg(sqlite3*); 3359const void *sqlite3_errmsg16(sqlite3*); 3360const char *sqlite3_errstr(int); 3361 3362/* 3363** CAPI3REF: Prepared Statement Object 3364** KEYWORDS: {prepared statement} {prepared statements} 3365** 3366** An instance of this object represents a single SQL statement that 3367** has been compiled into binary form and is ready to be evaluated. 3368** 3369** Think of each SQL statement as a separate computer program. The 3370** original SQL text is source code. A prepared statement object 3371** is the compiled object code. All SQL must be converted into a 3372** prepared statement before it can be run. 3373** 3374** The life-cycle of a prepared statement object usually goes like this: 3375** 3376** <ol> 3377** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3378** <li> Bind values to [parameters] using the sqlite3_bind_*() 3379** interfaces. 3380** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3381** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3382** to step 2. Do this zero or more times. 3383** <li> Destroy the object using [sqlite3_finalize()]. 3384** </ol> 3385*/ 3386typedef struct sqlite3_stmt sqlite3_stmt; 3387 3388/* 3389** CAPI3REF: Run-time Limits 3390** METHOD: sqlite3 3391** 3392** ^(This interface allows the size of various constructs to be limited 3393** on a connection by connection basis. The first parameter is the 3394** [database connection] whose limit is to be set or queried. The 3395** second parameter is one of the [limit categories] that define a 3396** class of constructs to be size limited. The third parameter is the 3397** new limit for that construct.)^ 3398** 3399** ^If the new limit is a negative number, the limit is unchanged. 3400** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3401** [limits | hard upper bound] 3402** set at compile-time by a C preprocessor macro called 3403** [limits | SQLITE_MAX_<i>NAME</i>]. 3404** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3405** ^Attempts to increase a limit above its hard upper bound are 3406** silently truncated to the hard upper bound. 3407** 3408** ^Regardless of whether or not the limit was changed, the 3409** [sqlite3_limit()] interface returns the prior value of the limit. 3410** ^Hence, to find the current value of a limit without changing it, 3411** simply invoke this interface with the third parameter set to -1. 3412** 3413** Run-time limits are intended for use in applications that manage 3414** both their own internal database and also databases that are controlled 3415** by untrusted external sources. An example application might be a 3416** web browser that has its own databases for storing history and 3417** separate databases controlled by JavaScript applications downloaded 3418** off the Internet. The internal databases can be given the 3419** large, default limits. Databases managed by external sources can 3420** be given much smaller limits designed to prevent a denial of service 3421** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3422** interface to further control untrusted SQL. The size of the database 3423** created by an untrusted script can be contained using the 3424** [max_page_count] [PRAGMA]. 3425** 3426** New run-time limit categories may be added in future releases. 3427*/ 3428int sqlite3_limit(sqlite3*, int id, int newVal); 3429 3430/* 3431** CAPI3REF: Run-Time Limit Categories 3432** KEYWORDS: {limit category} {*limit categories} 3433** 3434** These constants define various performance limits 3435** that can be lowered at run-time using [sqlite3_limit()]. 3436** The synopsis of the meanings of the various limits is shown below. 3437** Additional information is available at [limits | Limits in SQLite]. 3438** 3439** <dl> 3440** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3441** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3442** 3443** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3444** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3445** 3446** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3447** <dd>The maximum number of columns in a table definition or in the 3448** result set of a [SELECT] or the maximum number of columns in an index 3449** or in an ORDER BY or GROUP BY clause.</dd>)^ 3450** 3451** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3452** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3453** 3454** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3455** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3456** 3457** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3458** <dd>The maximum number of instructions in a virtual machine program 3459** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3460** the equivalent tries to allocate space for more than this many opcodes 3461** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3462** 3463** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3464** <dd>The maximum number of arguments on a function.</dd>)^ 3465** 3466** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3467** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3468** 3469** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3470** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3471** <dd>The maximum length of the pattern argument to the [LIKE] or 3472** [GLOB] operators.</dd>)^ 3473** 3474** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3475** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3476** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3477** 3478** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3479** <dd>The maximum depth of recursion for triggers.</dd>)^ 3480** 3481** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3482** <dd>The maximum number of auxiliary worker threads that a single 3483** [prepared statement] may start.</dd>)^ 3484** </dl> 3485*/ 3486#define SQLITE_LIMIT_LENGTH 0 3487#define SQLITE_LIMIT_SQL_LENGTH 1 3488#define SQLITE_LIMIT_COLUMN 2 3489#define SQLITE_LIMIT_EXPR_DEPTH 3 3490#define SQLITE_LIMIT_COMPOUND_SELECT 4 3491#define SQLITE_LIMIT_VDBE_OP 5 3492#define SQLITE_LIMIT_FUNCTION_ARG 6 3493#define SQLITE_LIMIT_ATTACHED 7 3494#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3495#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3496#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3497#define SQLITE_LIMIT_WORKER_THREADS 11 3498 3499/* 3500** CAPI3REF: Prepare Flags 3501** 3502** These constants define various flags that can be passed into 3503** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3504** [sqlite3_prepare16_v3()] interfaces. 3505** 3506** New flags may be added in future releases of SQLite. 3507** 3508** <dl> 3509** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3510** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3511** that the prepared statement will be retained for a long time and 3512** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3513** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3514** be used just once or at most a few times and then destroyed using 3515** [sqlite3_finalize()] relatively soon. The current implementation acts 3516** on this hint by avoiding the use of [lookaside memory] so as not to 3517** deplete the limited store of lookaside memory. Future versions of 3518** SQLite may act on this hint differently. 3519** </dl> 3520*/ 3521#define SQLITE_PREPARE_PERSISTENT 0x01 3522 3523/* 3524** CAPI3REF: Compiling An SQL Statement 3525** KEYWORDS: {SQL statement compiler} 3526** METHOD: sqlite3 3527** CONSTRUCTOR: sqlite3_stmt 3528** 3529** To execute an SQL statement, it must first be compiled into a byte-code 3530** program using one of these routines. Or, in other words, these routines 3531** are constructors for the [prepared statement] object. 3532** 3533** The preferred routine to use is [sqlite3_prepare_v2()]. The 3534** [sqlite3_prepare()] interface is legacy and should be avoided. 3535** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3536** for special purposes. 3537** 3538** The use of the UTF-8 interfaces is preferred, as SQLite currently 3539** does all parsing using UTF-8. The UTF-16 interfaces are provided 3540** as a convenience. The UTF-16 interfaces work by converting the 3541** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3542** 3543** The first argument, "db", is a [database connection] obtained from a 3544** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3545** [sqlite3_open16()]. The database connection must not have been closed. 3546** 3547** The second argument, "zSql", is the statement to be compiled, encoded 3548** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3549** and sqlite3_prepare_v3() 3550** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3551** and sqlite3_prepare16_v3() use UTF-16. 3552** 3553** ^If the nByte argument is negative, then zSql is read up to the 3554** first zero terminator. ^If nByte is positive, then it is the 3555** number of bytes read from zSql. ^If nByte is zero, then no prepared 3556** statement is generated. 3557** If the caller knows that the supplied string is nul-terminated, then 3558** there is a small performance advantage to passing an nByte parameter that 3559** is the number of bytes in the input string <i>including</i> 3560** the nul-terminator. 3561** 3562** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3563** past the end of the first SQL statement in zSql. These routines only 3564** compile the first statement in zSql, so *pzTail is left pointing to 3565** what remains uncompiled. 3566** 3567** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3568** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3569** to NULL. ^If the input text contains no SQL (if the input is an empty 3570** string or a comment) then *ppStmt is set to NULL. 3571** The calling procedure is responsible for deleting the compiled 3572** SQL statement using [sqlite3_finalize()] after it has finished with it. 3573** ppStmt may not be NULL. 3574** 3575** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3576** otherwise an [error code] is returned. 3577** 3578** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3579** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3580** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3581** are retained for backwards compatibility, but their use is discouraged. 3582** ^In the "vX" interfaces, the prepared statement 3583** that is returned (the [sqlite3_stmt] object) contains a copy of the 3584** original SQL text. This causes the [sqlite3_step()] interface to 3585** behave differently in three ways: 3586** 3587** <ol> 3588** <li> 3589** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3590** always used to do, [sqlite3_step()] will automatically recompile the SQL 3591** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3592** retries will occur before sqlite3_step() gives up and returns an error. 3593** </li> 3594** 3595** <li> 3596** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3597** [error codes] or [extended error codes]. ^The legacy behavior was that 3598** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3599** and the application would have to make a second call to [sqlite3_reset()] 3600** in order to find the underlying cause of the problem. With the "v2" prepare 3601** interfaces, the underlying reason for the error is returned immediately. 3602** </li> 3603** 3604** <li> 3605** ^If the specific value bound to [parameter | host parameter] in the 3606** WHERE clause might influence the choice of query plan for a statement, 3607** then the statement will be automatically recompiled, as if there had been 3608** a schema change, on the first [sqlite3_step()] call following any change 3609** to the [sqlite3_bind_text | bindings] of that [parameter]. 3610** ^The specific value of WHERE-clause [parameter] might influence the 3611** choice of query plan if the parameter is the left-hand side of a [LIKE] 3612** or [GLOB] operator or if the parameter is compared to an indexed column 3613** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3614** </li> 3615** </ol> 3616** 3617** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3618** the extra prepFlags parameter, which is a bit array consisting of zero or 3619** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3620** sqlite3_prepare_v2() interface works exactly the same as 3621** sqlite3_prepare_v3() with a zero prepFlags parameter. 3622*/ 3623int sqlite3_prepare( 3624 sqlite3 *db, /* Database handle */ 3625 const char *zSql, /* SQL statement, UTF-8 encoded */ 3626 int nByte, /* Maximum length of zSql in bytes. */ 3627 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3628 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3629); 3630int sqlite3_prepare_v2( 3631 sqlite3 *db, /* Database handle */ 3632 const char *zSql, /* SQL statement, UTF-8 encoded */ 3633 int nByte, /* Maximum length of zSql in bytes. */ 3634 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3635 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3636); 3637int sqlite3_prepare_v3( 3638 sqlite3 *db, /* Database handle */ 3639 const char *zSql, /* SQL statement, UTF-8 encoded */ 3640 int nByte, /* Maximum length of zSql in bytes. */ 3641 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3642 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3643 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3644); 3645int sqlite3_prepare16( 3646 sqlite3 *db, /* Database handle */ 3647 const void *zSql, /* SQL statement, UTF-16 encoded */ 3648 int nByte, /* Maximum length of zSql in bytes. */ 3649 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3650 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3651); 3652int sqlite3_prepare16_v2( 3653 sqlite3 *db, /* Database handle */ 3654 const void *zSql, /* SQL statement, UTF-16 encoded */ 3655 int nByte, /* Maximum length of zSql in bytes. */ 3656 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3657 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3658); 3659int sqlite3_prepare16_v3( 3660 sqlite3 *db, /* Database handle */ 3661 const void *zSql, /* SQL statement, UTF-16 encoded */ 3662 int nByte, /* Maximum length of zSql in bytes. */ 3663 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3664 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3665 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3666); 3667 3668/* 3669** CAPI3REF: Retrieving Statement SQL 3670** METHOD: sqlite3_stmt 3671** 3672** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3673** SQL text used to create [prepared statement] P if P was 3674** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3675** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3676** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3677** string containing the SQL text of prepared statement P with 3678** [bound parameters] expanded. 3679** 3680** ^(For example, if a prepared statement is created using the SQL 3681** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3682** and parameter :xyz is unbound, then sqlite3_sql() will return 3683** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3684** will return "SELECT 2345,NULL".)^ 3685** 3686** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3687** is available to hold the result, or if the result would exceed the 3688** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3689** 3690** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3691** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3692** option causes sqlite3_expanded_sql() to always return NULL. 3693** 3694** ^The string returned by sqlite3_sql(P) is managed by SQLite and is 3695** automatically freed when the prepared statement is finalized. 3696** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3697** is obtained from [sqlite3_malloc()] and must be free by the application 3698** by passing it to [sqlite3_free()]. 3699*/ 3700const char *sqlite3_sql(sqlite3_stmt *pStmt); 3701char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3702 3703/* 3704** CAPI3REF: Determine If An SQL Statement Writes The Database 3705** METHOD: sqlite3_stmt 3706** 3707** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3708** and only if the [prepared statement] X makes no direct changes to 3709** the content of the database file. 3710** 3711** Note that [application-defined SQL functions] or 3712** [virtual tables] might change the database indirectly as a side effect. 3713** ^(For example, if an application defines a function "eval()" that 3714** calls [sqlite3_exec()], then the following SQL statement would 3715** change the database file through side-effects: 3716** 3717** <blockquote><pre> 3718** SELECT eval('DELETE FROM t1') FROM t2; 3719** </pre></blockquote> 3720** 3721** But because the [SELECT] statement does not change the database file 3722** directly, sqlite3_stmt_readonly() would still return true.)^ 3723** 3724** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3725** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3726** since the statements themselves do not actually modify the database but 3727** rather they control the timing of when other statements modify the 3728** database. ^The [ATTACH] and [DETACH] statements also cause 3729** sqlite3_stmt_readonly() to return true since, while those statements 3730** change the configuration of a database connection, they do not make 3731** changes to the content of the database files on disk. 3732** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3733** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3734** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3735** sqlite3_stmt_readonly() returns false for those commands. 3736*/ 3737int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3738 3739/* 3740** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3741** METHOD: sqlite3_stmt 3742** 3743** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3744** [prepared statement] S has been stepped at least once using 3745** [sqlite3_step(S)] but has neither run to completion (returned 3746** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3747** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3748** interface returns false if S is a NULL pointer. If S is not a 3749** NULL pointer and is not a pointer to a valid [prepared statement] 3750** object, then the behavior is undefined and probably undesirable. 3751** 3752** This interface can be used in combination [sqlite3_next_stmt()] 3753** to locate all prepared statements associated with a database 3754** connection that are in need of being reset. This can be used, 3755** for example, in diagnostic routines to search for prepared 3756** statements that are holding a transaction open. 3757*/ 3758int sqlite3_stmt_busy(sqlite3_stmt*); 3759 3760/* 3761** CAPI3REF: Dynamically Typed Value Object 3762** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3763** 3764** SQLite uses the sqlite3_value object to represent all values 3765** that can be stored in a database table. SQLite uses dynamic typing 3766** for the values it stores. ^Values stored in sqlite3_value objects 3767** can be integers, floating point values, strings, BLOBs, or NULL. 3768** 3769** An sqlite3_value object may be either "protected" or "unprotected". 3770** Some interfaces require a protected sqlite3_value. Other interfaces 3771** will accept either a protected or an unprotected sqlite3_value. 3772** Every interface that accepts sqlite3_value arguments specifies 3773** whether or not it requires a protected sqlite3_value. The 3774** [sqlite3_value_dup()] interface can be used to construct a new 3775** protected sqlite3_value from an unprotected sqlite3_value. 3776** 3777** The terms "protected" and "unprotected" refer to whether or not 3778** a mutex is held. An internal mutex is held for a protected 3779** sqlite3_value object but no mutex is held for an unprotected 3780** sqlite3_value object. If SQLite is compiled to be single-threaded 3781** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3782** or if SQLite is run in one of reduced mutex modes 3783** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3784** then there is no distinction between protected and unprotected 3785** sqlite3_value objects and they can be used interchangeably. However, 3786** for maximum code portability it is recommended that applications 3787** still make the distinction between protected and unprotected 3788** sqlite3_value objects even when not strictly required. 3789** 3790** ^The sqlite3_value objects that are passed as parameters into the 3791** implementation of [application-defined SQL functions] are protected. 3792** ^The sqlite3_value object returned by 3793** [sqlite3_column_value()] is unprotected. 3794** Unprotected sqlite3_value objects may only be used as arguments 3795** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3796** [sqlite3_value_dup()]. 3797** The [sqlite3_value_blob | sqlite3_value_type()] family of 3798** interfaces require protected sqlite3_value objects. 3799*/ 3800typedef struct sqlite3_value sqlite3_value; 3801 3802/* 3803** CAPI3REF: SQL Function Context Object 3804** 3805** The context in which an SQL function executes is stored in an 3806** sqlite3_context object. ^A pointer to an sqlite3_context object 3807** is always first parameter to [application-defined SQL functions]. 3808** The application-defined SQL function implementation will pass this 3809** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3810** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3811** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3812** and/or [sqlite3_set_auxdata()]. 3813*/ 3814typedef struct sqlite3_context sqlite3_context; 3815 3816/* 3817** CAPI3REF: Binding Values To Prepared Statements 3818** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3819** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3820** METHOD: sqlite3_stmt 3821** 3822** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3823** literals may be replaced by a [parameter] that matches one of following 3824** templates: 3825** 3826** <ul> 3827** <li> ? 3828** <li> ?NNN 3829** <li> :VVV 3830** <li> @VVV 3831** <li> $VVV 3832** </ul> 3833** 3834** In the templates above, NNN represents an integer literal, 3835** and VVV represents an alphanumeric identifier.)^ ^The values of these 3836** parameters (also called "host parameter names" or "SQL parameters") 3837** can be set using the sqlite3_bind_*() routines defined here. 3838** 3839** ^The first argument to the sqlite3_bind_*() routines is always 3840** a pointer to the [sqlite3_stmt] object returned from 3841** [sqlite3_prepare_v2()] or its variants. 3842** 3843** ^The second argument is the index of the SQL parameter to be set. 3844** ^The leftmost SQL parameter has an index of 1. ^When the same named 3845** SQL parameter is used more than once, second and subsequent 3846** occurrences have the same index as the first occurrence. 3847** ^The index for named parameters can be looked up using the 3848** [sqlite3_bind_parameter_index()] API if desired. ^The index 3849** for "?NNN" parameters is the value of NNN. 3850** ^The NNN value must be between 1 and the [sqlite3_limit()] 3851** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3852** 3853** ^The third argument is the value to bind to the parameter. 3854** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3855** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 3856** is ignored and the end result is the same as sqlite3_bind_null(). 3857** 3858** ^(In those routines that have a fourth argument, its value is the 3859** number of bytes in the parameter. To be clear: the value is the 3860** number of <u>bytes</u> in the value, not the number of characters.)^ 3861** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 3862** is negative, then the length of the string is 3863** the number of bytes up to the first zero terminator. 3864** If the fourth parameter to sqlite3_bind_blob() is negative, then 3865** the behavior is undefined. 3866** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3867** or sqlite3_bind_text16() or sqlite3_bind_text64() then 3868** that parameter must be the byte offset 3869** where the NUL terminator would occur assuming the string were NUL 3870** terminated. If any NUL characters occur at byte offsets less than 3871** the value of the fourth parameter then the resulting string value will 3872** contain embedded NULs. The result of expressions involving strings 3873** with embedded NULs is undefined. 3874** 3875** ^The fifth argument to the BLOB and string binding interfaces 3876** is a destructor used to dispose of the BLOB or 3877** string after SQLite has finished with it. ^The destructor is called 3878** to dispose of the BLOB or string even if the call to bind API fails. 3879** ^If the fifth argument is 3880** the special value [SQLITE_STATIC], then SQLite assumes that the 3881** information is in static, unmanaged space and does not need to be freed. 3882** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3883** SQLite makes its own private copy of the data immediately, before 3884** the sqlite3_bind_*() routine returns. 3885** 3886** ^The sixth argument to sqlite3_bind_text64() must be one of 3887** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 3888** to specify the encoding of the text in the third parameter. If 3889** the sixth argument to sqlite3_bind_text64() is not one of the 3890** allowed values shown above, or if the text encoding is different 3891** from the encoding specified by the sixth parameter, then the behavior 3892** is undefined. 3893** 3894** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3895** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3896** (just an integer to hold its size) while it is being processed. 3897** Zeroblobs are intended to serve as placeholders for BLOBs whose 3898** content is later written using 3899** [sqlite3_blob_open | incremental BLOB I/O] routines. 3900** ^A negative value for the zeroblob results in a zero-length BLOB. 3901** 3902** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 3903** [prepared statement] S to have an SQL value of NULL, but to also be 3904** associated with the pointer P of type T. ^D is either a NULL pointer or 3905** a pointer to a destructor function for P. ^SQLite will invoke the 3906** destructor D with a single argument of P when it is finished using 3907** P. The T parameter should be a static string, preferably a string 3908** literal. The sqlite3_bind_pointer() routine is part of the 3909** [pointer passing interface] added for SQLite 3.20.0. 3910** 3911** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3912** for the [prepared statement] or with a prepared statement for which 3913** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3914** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3915** routine is passed a [prepared statement] that has been finalized, the 3916** result is undefined and probably harmful. 3917** 3918** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3919** ^Unbound parameters are interpreted as NULL. 3920** 3921** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3922** [error code] if anything goes wrong. 3923** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 3924** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 3925** [SQLITE_MAX_LENGTH]. 3926** ^[SQLITE_RANGE] is returned if the parameter 3927** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3928** 3929** See also: [sqlite3_bind_parameter_count()], 3930** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3931*/ 3932int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3933int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 3934 void(*)(void*)); 3935int sqlite3_bind_double(sqlite3_stmt*, int, double); 3936int sqlite3_bind_int(sqlite3_stmt*, int, int); 3937int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3938int sqlite3_bind_null(sqlite3_stmt*, int); 3939int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 3940int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3941int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 3942 void(*)(void*), unsigned char encoding); 3943int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3944int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 3945int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3946int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 3947 3948/* 3949** CAPI3REF: Number Of SQL Parameters 3950** METHOD: sqlite3_stmt 3951** 3952** ^This routine can be used to find the number of [SQL parameters] 3953** in a [prepared statement]. SQL parameters are tokens of the 3954** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3955** placeholders for values that are [sqlite3_bind_blob | bound] 3956** to the parameters at a later time. 3957** 3958** ^(This routine actually returns the index of the largest (rightmost) 3959** parameter. For all forms except ?NNN, this will correspond to the 3960** number of unique parameters. If parameters of the ?NNN form are used, 3961** there may be gaps in the list.)^ 3962** 3963** See also: [sqlite3_bind_blob|sqlite3_bind()], 3964** [sqlite3_bind_parameter_name()], and 3965** [sqlite3_bind_parameter_index()]. 3966*/ 3967int sqlite3_bind_parameter_count(sqlite3_stmt*); 3968 3969/* 3970** CAPI3REF: Name Of A Host Parameter 3971** METHOD: sqlite3_stmt 3972** 3973** ^The sqlite3_bind_parameter_name(P,N) interface returns 3974** the name of the N-th [SQL parameter] in the [prepared statement] P. 3975** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3976** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3977** respectively. 3978** In other words, the initial ":" or "$" or "@" or "?" 3979** is included as part of the name.)^ 3980** ^Parameters of the form "?" without a following integer have no name 3981** and are referred to as "nameless" or "anonymous parameters". 3982** 3983** ^The first host parameter has an index of 1, not 0. 3984** 3985** ^If the value N is out of range or if the N-th parameter is 3986** nameless, then NULL is returned. ^The returned string is 3987** always in UTF-8 encoding even if the named parameter was 3988** originally specified as UTF-16 in [sqlite3_prepare16()], 3989** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3990** 3991** See also: [sqlite3_bind_blob|sqlite3_bind()], 3992** [sqlite3_bind_parameter_count()], and 3993** [sqlite3_bind_parameter_index()]. 3994*/ 3995const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3996 3997/* 3998** CAPI3REF: Index Of A Parameter With A Given Name 3999** METHOD: sqlite3_stmt 4000** 4001** ^Return the index of an SQL parameter given its name. ^The 4002** index value returned is suitable for use as the second 4003** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4004** is returned if no matching parameter is found. ^The parameter 4005** name must be given in UTF-8 even if the original statement 4006** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4007** [sqlite3_prepare16_v3()]. 4008** 4009** See also: [sqlite3_bind_blob|sqlite3_bind()], 4010** [sqlite3_bind_parameter_count()], and 4011** [sqlite3_bind_parameter_name()]. 4012*/ 4013int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4014 4015/* 4016** CAPI3REF: Reset All Bindings On A Prepared Statement 4017** METHOD: sqlite3_stmt 4018** 4019** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4020** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4021** ^Use this routine to reset all host parameters to NULL. 4022*/ 4023int sqlite3_clear_bindings(sqlite3_stmt*); 4024 4025/* 4026** CAPI3REF: Number Of Columns In A Result Set 4027** METHOD: sqlite3_stmt 4028** 4029** ^Return the number of columns in the result set returned by the 4030** [prepared statement]. ^If this routine returns 0, that means the 4031** [prepared statement] returns no data (for example an [UPDATE]). 4032** ^However, just because this routine returns a positive number does not 4033** mean that one or more rows of data will be returned. ^A SELECT statement 4034** will always have a positive sqlite3_column_count() but depending on the 4035** WHERE clause constraints and the table content, it might return no rows. 4036** 4037** See also: [sqlite3_data_count()] 4038*/ 4039int sqlite3_column_count(sqlite3_stmt *pStmt); 4040 4041/* 4042** CAPI3REF: Column Names In A Result Set 4043** METHOD: sqlite3_stmt 4044** 4045** ^These routines return the name assigned to a particular column 4046** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4047** interface returns a pointer to a zero-terminated UTF-8 string 4048** and sqlite3_column_name16() returns a pointer to a zero-terminated 4049** UTF-16 string. ^The first parameter is the [prepared statement] 4050** that implements the [SELECT] statement. ^The second parameter is the 4051** column number. ^The leftmost column is number 0. 4052** 4053** ^The returned string pointer is valid until either the [prepared statement] 4054** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4055** reprepared by the first call to [sqlite3_step()] for a particular run 4056** or until the next call to 4057** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4058** 4059** ^If sqlite3_malloc() fails during the processing of either routine 4060** (for example during a conversion from UTF-8 to UTF-16) then a 4061** NULL pointer is returned. 4062** 4063** ^The name of a result column is the value of the "AS" clause for 4064** that column, if there is an AS clause. If there is no AS clause 4065** then the name of the column is unspecified and may change from 4066** one release of SQLite to the next. 4067*/ 4068const char *sqlite3_column_name(sqlite3_stmt*, int N); 4069const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4070 4071/* 4072** CAPI3REF: Source Of Data In A Query Result 4073** METHOD: sqlite3_stmt 4074** 4075** ^These routines provide a means to determine the database, table, and 4076** table column that is the origin of a particular result column in 4077** [SELECT] statement. 4078** ^The name of the database or table or column can be returned as 4079** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4080** the database name, the _table_ routines return the table name, and 4081** the origin_ routines return the column name. 4082** ^The returned string is valid until the [prepared statement] is destroyed 4083** using [sqlite3_finalize()] or until the statement is automatically 4084** reprepared by the first call to [sqlite3_step()] for a particular run 4085** or until the same information is requested 4086** again in a different encoding. 4087** 4088** ^The names returned are the original un-aliased names of the 4089** database, table, and column. 4090** 4091** ^The first argument to these interfaces is a [prepared statement]. 4092** ^These functions return information about the Nth result column returned by 4093** the statement, where N is the second function argument. 4094** ^The left-most column is column 0 for these routines. 4095** 4096** ^If the Nth column returned by the statement is an expression or 4097** subquery and is not a column value, then all of these functions return 4098** NULL. ^These routine might also return NULL if a memory allocation error 4099** occurs. ^Otherwise, they return the name of the attached database, table, 4100** or column that query result column was extracted from. 4101** 4102** ^As with all other SQLite APIs, those whose names end with "16" return 4103** UTF-16 encoded strings and the other functions return UTF-8. 4104** 4105** ^These APIs are only available if the library was compiled with the 4106** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4107** 4108** If two or more threads call one or more of these routines against the same 4109** prepared statement and column at the same time then the results are 4110** undefined. 4111** 4112** If two or more threads call one or more 4113** [sqlite3_column_database_name | column metadata interfaces] 4114** for the same [prepared statement] and result column 4115** at the same time then the results are undefined. 4116*/ 4117const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4118const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4119const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4120const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4121const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4122const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4123 4124/* 4125** CAPI3REF: Declared Datatype Of A Query Result 4126** METHOD: sqlite3_stmt 4127** 4128** ^(The first parameter is a [prepared statement]. 4129** If this statement is a [SELECT] statement and the Nth column of the 4130** returned result set of that [SELECT] is a table column (not an 4131** expression or subquery) then the declared type of the table 4132** column is returned.)^ ^If the Nth column of the result set is an 4133** expression or subquery, then a NULL pointer is returned. 4134** ^The returned string is always UTF-8 encoded. 4135** 4136** ^(For example, given the database schema: 4137** 4138** CREATE TABLE t1(c1 VARIANT); 4139** 4140** and the following statement to be compiled: 4141** 4142** SELECT c1 + 1, c1 FROM t1; 4143** 4144** this routine would return the string "VARIANT" for the second result 4145** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4146** 4147** ^SQLite uses dynamic run-time typing. ^So just because a column 4148** is declared to contain a particular type does not mean that the 4149** data stored in that column is of the declared type. SQLite is 4150** strongly typed, but the typing is dynamic not static. ^Type 4151** is associated with individual values, not with the containers 4152** used to hold those values. 4153*/ 4154const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4155const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4156 4157/* 4158** CAPI3REF: Evaluate An SQL Statement 4159** METHOD: sqlite3_stmt 4160** 4161** After a [prepared statement] has been prepared using any of 4162** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4163** or [sqlite3_prepare16_v3()] or one of the legacy 4164** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4165** must be called one or more times to evaluate the statement. 4166** 4167** The details of the behavior of the sqlite3_step() interface depend 4168** on whether the statement was prepared using the newer "vX" interfaces 4169** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4170** [sqlite3_prepare16_v2()] or the older legacy 4171** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4172** new "vX" interface is recommended for new applications but the legacy 4173** interface will continue to be supported. 4174** 4175** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4176** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4177** ^With the "v2" interface, any of the other [result codes] or 4178** [extended result codes] might be returned as well. 4179** 4180** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4181** database locks it needs to do its job. ^If the statement is a [COMMIT] 4182** or occurs outside of an explicit transaction, then you can retry the 4183** statement. If the statement is not a [COMMIT] and occurs within an 4184** explicit transaction then you should rollback the transaction before 4185** continuing. 4186** 4187** ^[SQLITE_DONE] means that the statement has finished executing 4188** successfully. sqlite3_step() should not be called again on this virtual 4189** machine without first calling [sqlite3_reset()] to reset the virtual 4190** machine back to its initial state. 4191** 4192** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4193** is returned each time a new row of data is ready for processing by the 4194** caller. The values may be accessed using the [column access functions]. 4195** sqlite3_step() is called again to retrieve the next row of data. 4196** 4197** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4198** violation) has occurred. sqlite3_step() should not be called again on 4199** the VM. More information may be found by calling [sqlite3_errmsg()]. 4200** ^With the legacy interface, a more specific error code (for example, 4201** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4202** can be obtained by calling [sqlite3_reset()] on the 4203** [prepared statement]. ^In the "v2" interface, 4204** the more specific error code is returned directly by sqlite3_step(). 4205** 4206** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4207** Perhaps it was called on a [prepared statement] that has 4208** already been [sqlite3_finalize | finalized] or on one that had 4209** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4210** be the case that the same database connection is being used by two or 4211** more threads at the same moment in time. 4212** 4213** For all versions of SQLite up to and including 3.6.23.1, a call to 4214** [sqlite3_reset()] was required after sqlite3_step() returned anything 4215** other than [SQLITE_ROW] before any subsequent invocation of 4216** sqlite3_step(). Failure to reset the prepared statement using 4217** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4218** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4219** sqlite3_step() began 4220** calling [sqlite3_reset()] automatically in this circumstance rather 4221** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4222** break because any application that ever receives an SQLITE_MISUSE error 4223** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4224** can be used to restore the legacy behavior. 4225** 4226** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4227** API always returns a generic error code, [SQLITE_ERROR], following any 4228** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4229** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4230** specific [error codes] that better describes the error. 4231** We admit that this is a goofy design. The problem has been fixed 4232** with the "v2" interface. If you prepare all of your SQL statements 4233** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4234** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4235** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4236** then the more specific [error codes] are returned directly 4237** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4238*/ 4239int sqlite3_step(sqlite3_stmt*); 4240 4241/* 4242** CAPI3REF: Number of columns in a result set 4243** METHOD: sqlite3_stmt 4244** 4245** ^The sqlite3_data_count(P) interface returns the number of columns in the 4246** current row of the result set of [prepared statement] P. 4247** ^If prepared statement P does not have results ready to return 4248** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4249** interfaces) then sqlite3_data_count(P) returns 0. 4250** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4251** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4252** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4253** will return non-zero if previous call to [sqlite3_step](P) returned 4254** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4255** where it always returns zero since each step of that multi-step 4256** pragma returns 0 columns of data. 4257** 4258** See also: [sqlite3_column_count()] 4259*/ 4260int sqlite3_data_count(sqlite3_stmt *pStmt); 4261 4262/* 4263** CAPI3REF: Fundamental Datatypes 4264** KEYWORDS: SQLITE_TEXT 4265** 4266** ^(Every value in SQLite has one of five fundamental datatypes: 4267** 4268** <ul> 4269** <li> 64-bit signed integer 4270** <li> 64-bit IEEE floating point number 4271** <li> string 4272** <li> BLOB 4273** <li> NULL 4274** </ul>)^ 4275** 4276** These constants are codes for each of those types. 4277** 4278** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4279** for a completely different meaning. Software that links against both 4280** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4281** SQLITE_TEXT. 4282*/ 4283#define SQLITE_INTEGER 1 4284#define SQLITE_FLOAT 2 4285#define SQLITE_BLOB 4 4286#define SQLITE_NULL 5 4287#ifdef SQLITE_TEXT 4288# undef SQLITE_TEXT 4289#else 4290# define SQLITE_TEXT 3 4291#endif 4292#define SQLITE3_TEXT 3 4293 4294/* 4295** CAPI3REF: Result Values From A Query 4296** KEYWORDS: {column access functions} 4297** METHOD: sqlite3_stmt 4298** 4299** <b>Summary:</b> 4300** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4301** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4302** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4303** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4304** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4305** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4306** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4307** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4308** [sqlite3_value|unprotected sqlite3_value] object. 4309** <tr><td> <td> <td> 4310** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4311** or a UTF-8 TEXT result in bytes 4312** <tr><td><b>sqlite3_column_bytes16 </b> 4313** <td>→ <td>Size of UTF-16 4314** TEXT in bytes 4315** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4316** datatype of the result 4317** </table></blockquote> 4318** 4319** <b>Details:</b> 4320** 4321** ^These routines return information about a single column of the current 4322** result row of a query. ^In every case the first argument is a pointer 4323** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4324** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4325** and the second argument is the index of the column for which information 4326** should be returned. ^The leftmost column of the result set has the index 0. 4327** ^The number of columns in the result can be determined using 4328** [sqlite3_column_count()]. 4329** 4330** If the SQL statement does not currently point to a valid row, or if the 4331** column index is out of range, the result is undefined. 4332** These routines may only be called when the most recent call to 4333** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4334** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4335** If any of these routines are called after [sqlite3_reset()] or 4336** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4337** something other than [SQLITE_ROW], the results are undefined. 4338** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4339** are called from a different thread while any of these routines 4340** are pending, then the results are undefined. 4341** 4342** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4343** each return the value of a result column in a specific data format. If 4344** the result column is not initially in the requested format (for example, 4345** if the query returns an integer but the sqlite3_column_text() interface 4346** is used to extract the value) then an automatic type conversion is performed. 4347** 4348** ^The sqlite3_column_type() routine returns the 4349** [SQLITE_INTEGER | datatype code] for the initial data type 4350** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4351** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4352** The return value of sqlite3_column_type() can be used to decide which 4353** of the first six interface should be used to extract the column value. 4354** The value returned by sqlite3_column_type() is only meaningful if no 4355** automatic type conversions have occurred for the value in question. 4356** After a type conversion, the result of calling sqlite3_column_type() 4357** is undefined, though harmless. Future 4358** versions of SQLite may change the behavior of sqlite3_column_type() 4359** following a type conversion. 4360** 4361** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4362** or sqlite3_column_bytes16() interfaces can be used to determine the size 4363** of that BLOB or string. 4364** 4365** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4366** routine returns the number of bytes in that BLOB or string. 4367** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4368** the string to UTF-8 and then returns the number of bytes. 4369** ^If the result is a numeric value then sqlite3_column_bytes() uses 4370** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4371** the number of bytes in that string. 4372** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4373** 4374** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4375** routine returns the number of bytes in that BLOB or string. 4376** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4377** the string to UTF-16 and then returns the number of bytes. 4378** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4379** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4380** the number of bytes in that string. 4381** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4382** 4383** ^The values returned by [sqlite3_column_bytes()] and 4384** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4385** of the string. ^For clarity: the values returned by 4386** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4387** bytes in the string, not the number of characters. 4388** 4389** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4390** even empty strings, are always zero-terminated. ^The return 4391** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4392** 4393** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4394** [unprotected sqlite3_value] object. In a multithreaded environment, 4395** an unprotected sqlite3_value object may only be used safely with 4396** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4397** If the [unprotected sqlite3_value] object returned by 4398** [sqlite3_column_value()] is used in any other way, including calls 4399** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4400** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4401** Hence, the sqlite3_column_value() interface 4402** is normally only useful within the implementation of 4403** [application-defined SQL functions] or [virtual tables], not within 4404** top-level application code. 4405** 4406** The these routines may attempt to convert the datatype of the result. 4407** ^For example, if the internal representation is FLOAT and a text result 4408** is requested, [sqlite3_snprintf()] is used internally to perform the 4409** conversion automatically. ^(The following table details the conversions 4410** that are applied: 4411** 4412** <blockquote> 4413** <table border="1"> 4414** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4415** 4416** <tr><td> NULL <td> INTEGER <td> Result is 0 4417** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4418** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4419** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4420** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4421** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4422** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4423** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4424** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4425** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4426** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4427** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4428** <tr><td> TEXT <td> BLOB <td> No change 4429** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4430** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4431** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4432** </table> 4433** </blockquote>)^ 4434** 4435** Note that when type conversions occur, pointers returned by prior 4436** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4437** sqlite3_column_text16() may be invalidated. 4438** Type conversions and pointer invalidations might occur 4439** in the following cases: 4440** 4441** <ul> 4442** <li> The initial content is a BLOB and sqlite3_column_text() or 4443** sqlite3_column_text16() is called. A zero-terminator might 4444** need to be added to the string.</li> 4445** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4446** sqlite3_column_text16() is called. The content must be converted 4447** to UTF-16.</li> 4448** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4449** sqlite3_column_text() is called. The content must be converted 4450** to UTF-8.</li> 4451** </ul> 4452** 4453** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4454** not invalidate a prior pointer, though of course the content of the buffer 4455** that the prior pointer references will have been modified. Other kinds 4456** of conversion are done in place when it is possible, but sometimes they 4457** are not possible and in those cases prior pointers are invalidated. 4458** 4459** The safest policy is to invoke these routines 4460** in one of the following ways: 4461** 4462** <ul> 4463** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4464** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4465** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4466** </ul> 4467** 4468** In other words, you should call sqlite3_column_text(), 4469** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4470** into the desired format, then invoke sqlite3_column_bytes() or 4471** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4472** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4473** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4474** with calls to sqlite3_column_bytes(). 4475** 4476** ^The pointers returned are valid until a type conversion occurs as 4477** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4478** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4479** and BLOBs is freed automatically. Do not pass the pointers returned 4480** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4481** [sqlite3_free()]. 4482** 4483** ^(If a memory allocation error occurs during the evaluation of any 4484** of these routines, a default value is returned. The default value 4485** is either the integer 0, the floating point number 0.0, or a NULL 4486** pointer. Subsequent calls to [sqlite3_errcode()] will return 4487** [SQLITE_NOMEM].)^ 4488*/ 4489const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4490double sqlite3_column_double(sqlite3_stmt*, int iCol); 4491int sqlite3_column_int(sqlite3_stmt*, int iCol); 4492sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4493const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4494const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4495sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4496int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4497int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4498int sqlite3_column_type(sqlite3_stmt*, int iCol); 4499 4500/* 4501** CAPI3REF: Destroy A Prepared Statement Object 4502** DESTRUCTOR: sqlite3_stmt 4503** 4504** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4505** ^If the most recent evaluation of the statement encountered no errors 4506** or if the statement is never been evaluated, then sqlite3_finalize() returns 4507** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4508** sqlite3_finalize(S) returns the appropriate [error code] or 4509** [extended error code]. 4510** 4511** ^The sqlite3_finalize(S) routine can be called at any point during 4512** the life cycle of [prepared statement] S: 4513** before statement S is ever evaluated, after 4514** one or more calls to [sqlite3_reset()], or after any call 4515** to [sqlite3_step()] regardless of whether or not the statement has 4516** completed execution. 4517** 4518** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4519** 4520** The application must finalize every [prepared statement] in order to avoid 4521** resource leaks. It is a grievous error for the application to try to use 4522** a prepared statement after it has been finalized. Any use of a prepared 4523** statement after it has been finalized can result in undefined and 4524** undesirable behavior such as segfaults and heap corruption. 4525*/ 4526int sqlite3_finalize(sqlite3_stmt *pStmt); 4527 4528/* 4529** CAPI3REF: Reset A Prepared Statement Object 4530** METHOD: sqlite3_stmt 4531** 4532** The sqlite3_reset() function is called to reset a [prepared statement] 4533** object back to its initial state, ready to be re-executed. 4534** ^Any SQL statement variables that had values bound to them using 4535** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4536** Use [sqlite3_clear_bindings()] to reset the bindings. 4537** 4538** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4539** back to the beginning of its program. 4540** 4541** ^If the most recent call to [sqlite3_step(S)] for the 4542** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4543** or if [sqlite3_step(S)] has never before been called on S, 4544** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4545** 4546** ^If the most recent call to [sqlite3_step(S)] for the 4547** [prepared statement] S indicated an error, then 4548** [sqlite3_reset(S)] returns an appropriate [error code]. 4549** 4550** ^The [sqlite3_reset(S)] interface does not change the values 4551** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4552*/ 4553int sqlite3_reset(sqlite3_stmt *pStmt); 4554 4555/* 4556** CAPI3REF: Create Or Redefine SQL Functions 4557** KEYWORDS: {function creation routines} 4558** KEYWORDS: {application-defined SQL function} 4559** KEYWORDS: {application-defined SQL functions} 4560** METHOD: sqlite3 4561** 4562** ^These functions (collectively known as "function creation routines") 4563** are used to add SQL functions or aggregates or to redefine the behavior 4564** of existing SQL functions or aggregates. The only differences between 4565** these routines are the text encoding expected for 4566** the second parameter (the name of the function being created) 4567** and the presence or absence of a destructor callback for 4568** the application data pointer. 4569** 4570** ^The first parameter is the [database connection] to which the SQL 4571** function is to be added. ^If an application uses more than one database 4572** connection then application-defined SQL functions must be added 4573** to each database connection separately. 4574** 4575** ^The second parameter is the name of the SQL function to be created or 4576** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4577** representation, exclusive of the zero-terminator. ^Note that the name 4578** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4579** ^Any attempt to create a function with a longer name 4580** will result in [SQLITE_MISUSE] being returned. 4581** 4582** ^The third parameter (nArg) 4583** is the number of arguments that the SQL function or 4584** aggregate takes. ^If this parameter is -1, then the SQL function or 4585** aggregate may take any number of arguments between 0 and the limit 4586** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4587** parameter is less than -1 or greater than 127 then the behavior is 4588** undefined. 4589** 4590** ^The fourth parameter, eTextRep, specifies what 4591** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4592** its parameters. The application should set this parameter to 4593** [SQLITE_UTF16LE] if the function implementation invokes 4594** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4595** implementation invokes [sqlite3_value_text16be()] on an input, or 4596** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4597** otherwise. ^The same SQL function may be registered multiple times using 4598** different preferred text encodings, with different implementations for 4599** each encoding. 4600** ^When multiple implementations of the same function are available, SQLite 4601** will pick the one that involves the least amount of data conversion. 4602** 4603** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4604** to signal that the function will always return the same result given 4605** the same inputs within a single SQL statement. Most SQL functions are 4606** deterministic. The built-in [random()] SQL function is an example of a 4607** function that is not deterministic. The SQLite query planner is able to 4608** perform additional optimizations on deterministic functions, so use 4609** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4610** 4611** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4612** function can gain access to this pointer using [sqlite3_user_data()].)^ 4613** 4614** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 4615** pointers to C-language functions that implement the SQL function or 4616** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4617** callback only; NULL pointers must be passed as the xStep and xFinal 4618** parameters. ^An aggregate SQL function requires an implementation of xStep 4619** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4620** SQL function or aggregate, pass NULL pointers for all three function 4621** callbacks. 4622** 4623** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 4624** then it is destructor for the application data pointer. 4625** The destructor is invoked when the function is deleted, either by being 4626** overloaded or when the database connection closes.)^ 4627** ^The destructor is also invoked if the call to 4628** sqlite3_create_function_v2() fails. 4629** ^When the destructor callback of the tenth parameter is invoked, it 4630** is passed a single argument which is a copy of the application data 4631** pointer which was the fifth parameter to sqlite3_create_function_v2(). 4632** 4633** ^It is permitted to register multiple implementations of the same 4634** functions with the same name but with either differing numbers of 4635** arguments or differing preferred text encodings. ^SQLite will use 4636** the implementation that most closely matches the way in which the 4637** SQL function is used. ^A function implementation with a non-negative 4638** nArg parameter is a better match than a function implementation with 4639** a negative nArg. ^A function where the preferred text encoding 4640** matches the database encoding is a better 4641** match than a function where the encoding is different. 4642** ^A function where the encoding difference is between UTF16le and UTF16be 4643** is a closer match than a function where the encoding difference is 4644** between UTF8 and UTF16. 4645** 4646** ^Built-in functions may be overloaded by new application-defined functions. 4647** 4648** ^An application-defined function is permitted to call other 4649** SQLite interfaces. However, such calls must not 4650** close the database connection nor finalize or reset the prepared 4651** statement in which the function is running. 4652*/ 4653int sqlite3_create_function( 4654 sqlite3 *db, 4655 const char *zFunctionName, 4656 int nArg, 4657 int eTextRep, 4658 void *pApp, 4659 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4660 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4661 void (*xFinal)(sqlite3_context*) 4662); 4663int sqlite3_create_function16( 4664 sqlite3 *db, 4665 const void *zFunctionName, 4666 int nArg, 4667 int eTextRep, 4668 void *pApp, 4669 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4670 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4671 void (*xFinal)(sqlite3_context*) 4672); 4673int sqlite3_create_function_v2( 4674 sqlite3 *db, 4675 const char *zFunctionName, 4676 int nArg, 4677 int eTextRep, 4678 void *pApp, 4679 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4680 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4681 void (*xFinal)(sqlite3_context*), 4682 void(*xDestroy)(void*) 4683); 4684 4685/* 4686** CAPI3REF: Text Encodings 4687** 4688** These constant define integer codes that represent the various 4689** text encodings supported by SQLite. 4690*/ 4691#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4692#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4693#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4694#define SQLITE_UTF16 4 /* Use native byte order */ 4695#define SQLITE_ANY 5 /* Deprecated */ 4696#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4697 4698/* 4699** CAPI3REF: Function Flags 4700** 4701** These constants may be ORed together with the 4702** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4703** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4704** [sqlite3_create_function_v2()]. 4705*/ 4706#define SQLITE_DETERMINISTIC 0x800 4707 4708/* 4709** CAPI3REF: Deprecated Functions 4710** DEPRECATED 4711** 4712** These functions are [deprecated]. In order to maintain 4713** backwards compatibility with older code, these functions continue 4714** to be supported. However, new applications should avoid 4715** the use of these functions. To encourage programmers to avoid 4716** these functions, we will not explain what they do. 4717*/ 4718#ifndef SQLITE_OMIT_DEPRECATED 4719SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4720SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4721SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4722SQLITE_DEPRECATED int sqlite3_global_recover(void); 4723SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4724SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4725 void*,sqlite3_int64); 4726#endif 4727 4728/* 4729** CAPI3REF: Obtaining SQL Values 4730** METHOD: sqlite3_value 4731** 4732** <b>Summary:</b> 4733** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4734** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4735** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4736** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4737** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4738** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4739** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4740** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4741** the native byteorder 4742** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4743** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4744** <tr><td> <td> <td> 4745** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4746** or a UTF-8 TEXT in bytes 4747** <tr><td><b>sqlite3_value_bytes16 </b> 4748** <td>→ <td>Size of UTF-16 4749** TEXT in bytes 4750** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4751** datatype of the value 4752** <tr><td><b>sqlite3_value_numeric_type </b> 4753** <td>→ <td>Best numeric datatype of the value 4754** <tr><td><b>sqlite3_value_nochange </b> 4755** <td>→ <td>True if the column is unchanged in an UPDATE 4756** against a virtual table. 4757** </table></blockquote> 4758** 4759** <b>Details:</b> 4760** 4761** These routines extract type, size, and content information from 4762** [protected sqlite3_value] objects. Protected sqlite3_value objects 4763** are used to pass parameter information into implementation of 4764** [application-defined SQL functions] and [virtual tables]. 4765** 4766** These routines work only with [protected sqlite3_value] objects. 4767** Any attempt to use these routines on an [unprotected sqlite3_value] 4768** is not threadsafe. 4769** 4770** ^These routines work just like the corresponding [column access functions] 4771** except that these routines take a single [protected sqlite3_value] object 4772** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4773** 4774** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4775** in the native byte-order of the host machine. ^The 4776** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4777** extract UTF-16 strings as big-endian and little-endian respectively. 4778** 4779** ^If [sqlite3_value] object V was initialized 4780** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4781** and if X and Y are strings that compare equal according to strcmp(X,Y), 4782** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4783** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4784** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4785** 4786** ^(The sqlite3_value_type(V) interface returns the 4787** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4788** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4789** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 4790** Other interfaces might change the datatype for an sqlite3_value object. 4791** For example, if the datatype is initially SQLITE_INTEGER and 4792** sqlite3_value_text(V) is called to extract a text value for that 4793** integer, then subsequent calls to sqlite3_value_type(V) might return 4794** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 4795** occurs is undefined and may change from one release of SQLite to the next. 4796** 4797** ^(The sqlite3_value_numeric_type() interface attempts to apply 4798** numeric affinity to the value. This means that an attempt is 4799** made to convert the value to an integer or floating point. If 4800** such a conversion is possible without loss of information (in other 4801** words, if the value is a string that looks like a number) 4802** then the conversion is performed. Otherwise no conversion occurs. 4803** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 4804** 4805** ^Within the [xUpdate] method of a [virtual table], the 4806** sqlite3_value_nochange(X) interface returns true if and only if 4807** the column corresponding to X is unchanged by the UPDATE operation 4808** that the xUpdate method call was invoked to implement and if 4809** and the prior [xColumn] method call that was invoked to extracted 4810** the value for that column returned without setting a result (probably 4811** because it queried [sqlite3_vtab_nochange()] and found that the column 4812** was unchanging). ^Within an [xUpdate] method, any value for which 4813** sqlite3_value_nochange(X) is true will in all other respects appear 4814** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 4815** than within an [xUpdate] method call for an UPDATE statement, then 4816** the return value is arbitrary and meaningless. 4817** 4818** Please pay particular attention to the fact that the pointer returned 4819** from [sqlite3_value_blob()], [sqlite3_value_text()], or 4820** [sqlite3_value_text16()] can be invalidated by a subsequent call to 4821** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 4822** or [sqlite3_value_text16()]. 4823** 4824** These routines must be called from the same thread as 4825** the SQL function that supplied the [sqlite3_value*] parameters. 4826*/ 4827const void *sqlite3_value_blob(sqlite3_value*); 4828double sqlite3_value_double(sqlite3_value*); 4829int sqlite3_value_int(sqlite3_value*); 4830sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 4831void *sqlite3_value_pointer(sqlite3_value*, const char*); 4832const unsigned char *sqlite3_value_text(sqlite3_value*); 4833const void *sqlite3_value_text16(sqlite3_value*); 4834const void *sqlite3_value_text16le(sqlite3_value*); 4835const void *sqlite3_value_text16be(sqlite3_value*); 4836int sqlite3_value_bytes(sqlite3_value*); 4837int sqlite3_value_bytes16(sqlite3_value*); 4838int sqlite3_value_type(sqlite3_value*); 4839int sqlite3_value_numeric_type(sqlite3_value*); 4840int sqlite3_value_nochange(sqlite3_value*); 4841 4842/* 4843** CAPI3REF: Finding The Subtype Of SQL Values 4844** METHOD: sqlite3_value 4845** 4846** The sqlite3_value_subtype(V) function returns the subtype for 4847** an [application-defined SQL function] argument V. The subtype 4848** information can be used to pass a limited amount of context from 4849** one SQL function to another. Use the [sqlite3_result_subtype()] 4850** routine to set the subtype for the return value of an SQL function. 4851*/ 4852unsigned int sqlite3_value_subtype(sqlite3_value*); 4853 4854/* 4855** CAPI3REF: Copy And Free SQL Values 4856** METHOD: sqlite3_value 4857** 4858** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 4859** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 4860** is a [protected sqlite3_value] object even if the input is not. 4861** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 4862** memory allocation fails. 4863** 4864** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 4865** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 4866** then sqlite3_value_free(V) is a harmless no-op. 4867*/ 4868sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 4869void sqlite3_value_free(sqlite3_value*); 4870 4871/* 4872** CAPI3REF: Obtain Aggregate Function Context 4873** METHOD: sqlite3_context 4874** 4875** Implementations of aggregate SQL functions use this 4876** routine to allocate memory for storing their state. 4877** 4878** ^The first time the sqlite3_aggregate_context(C,N) routine is called 4879** for a particular aggregate function, SQLite 4880** allocates N of memory, zeroes out that memory, and returns a pointer 4881** to the new memory. ^On second and subsequent calls to 4882** sqlite3_aggregate_context() for the same aggregate function instance, 4883** the same buffer is returned. Sqlite3_aggregate_context() is normally 4884** called once for each invocation of the xStep callback and then one 4885** last time when the xFinal callback is invoked. ^(When no rows match 4886** an aggregate query, the xStep() callback of the aggregate function 4887** implementation is never called and xFinal() is called exactly once. 4888** In those cases, sqlite3_aggregate_context() might be called for the 4889** first time from within xFinal().)^ 4890** 4891** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 4892** when first called if N is less than or equal to zero or if a memory 4893** allocate error occurs. 4894** 4895** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 4896** determined by the N parameter on first successful call. Changing the 4897** value of N in subsequent call to sqlite3_aggregate_context() within 4898** the same aggregate function instance will not resize the memory 4899** allocation.)^ Within the xFinal callback, it is customary to set 4900** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 4901** pointless memory allocations occur. 4902** 4903** ^SQLite automatically frees the memory allocated by 4904** sqlite3_aggregate_context() when the aggregate query concludes. 4905** 4906** The first parameter must be a copy of the 4907** [sqlite3_context | SQL function context] that is the first parameter 4908** to the xStep or xFinal callback routine that implements the aggregate 4909** function. 4910** 4911** This routine must be called from the same thread in which 4912** the aggregate SQL function is running. 4913*/ 4914void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4915 4916/* 4917** CAPI3REF: User Data For Functions 4918** METHOD: sqlite3_context 4919** 4920** ^The sqlite3_user_data() interface returns a copy of 4921** the pointer that was the pUserData parameter (the 5th parameter) 4922** of the [sqlite3_create_function()] 4923** and [sqlite3_create_function16()] routines that originally 4924** registered the application defined function. 4925** 4926** This routine must be called from the same thread in which 4927** the application-defined function is running. 4928*/ 4929void *sqlite3_user_data(sqlite3_context*); 4930 4931/* 4932** CAPI3REF: Database Connection For Functions 4933** METHOD: sqlite3_context 4934** 4935** ^The sqlite3_context_db_handle() interface returns a copy of 4936** the pointer to the [database connection] (the 1st parameter) 4937** of the [sqlite3_create_function()] 4938** and [sqlite3_create_function16()] routines that originally 4939** registered the application defined function. 4940*/ 4941sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4942 4943/* 4944** CAPI3REF: Function Auxiliary Data 4945** METHOD: sqlite3_context 4946** 4947** These functions may be used by (non-aggregate) SQL functions to 4948** associate metadata with argument values. If the same value is passed to 4949** multiple invocations of the same SQL function during query execution, under 4950** some circumstances the associated metadata may be preserved. An example 4951** of where this might be useful is in a regular-expression matching 4952** function. The compiled version of the regular expression can be stored as 4953** metadata associated with the pattern string. 4954** Then as long as the pattern string remains the same, 4955** the compiled regular expression can be reused on multiple 4956** invocations of the same function. 4957** 4958** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 4959** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 4960** value to the application-defined function. ^N is zero for the left-most 4961** function argument. ^If there is no metadata 4962** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 4963** returns a NULL pointer. 4964** 4965** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 4966** argument of the application-defined function. ^Subsequent 4967** calls to sqlite3_get_auxdata(C,N) return P from the most recent 4968** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 4969** NULL if the metadata has been discarded. 4970** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 4971** SQLite will invoke the destructor function X with parameter P exactly 4972** once, when the metadata is discarded. 4973** SQLite is free to discard the metadata at any time, including: <ul> 4974** <li> ^(when the corresponding function parameter changes)^, or 4975** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 4976** SQL statement)^, or 4977** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 4978** parameter)^, or 4979** <li> ^(during the original sqlite3_set_auxdata() call when a memory 4980** allocation error occurs.)^ </ul> 4981** 4982** Note the last bullet in particular. The destructor X in 4983** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 4984** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 4985** should be called near the end of the function implementation and the 4986** function implementation should not make any use of P after 4987** sqlite3_set_auxdata() has been called. 4988** 4989** ^(In practice, metadata is preserved between function calls for 4990** function parameters that are compile-time constants, including literal 4991** values and [parameters] and expressions composed from the same.)^ 4992** 4993** The value of the N parameter to these interfaces should be non-negative. 4994** Future enhancements may make use of negative N values to define new 4995** kinds of function caching behavior. 4996** 4997** These routines must be called from the same thread in which 4998** the SQL function is running. 4999*/ 5000void *sqlite3_get_auxdata(sqlite3_context*, int N); 5001void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5002 5003 5004/* 5005** CAPI3REF: Constants Defining Special Destructor Behavior 5006** 5007** These are special values for the destructor that is passed in as the 5008** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5009** argument is SQLITE_STATIC, it means that the content pointer is constant 5010** and will never change. It does not need to be destroyed. ^The 5011** SQLITE_TRANSIENT value means that the content will likely change in 5012** the near future and that SQLite should make its own private copy of 5013** the content before returning. 5014** 5015** The typedef is necessary to work around problems in certain 5016** C++ compilers. 5017*/ 5018typedef void (*sqlite3_destructor_type)(void*); 5019#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5020#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5021 5022/* 5023** CAPI3REF: Setting The Result Of An SQL Function 5024** METHOD: sqlite3_context 5025** 5026** These routines are used by the xFunc or xFinal callbacks that 5027** implement SQL functions and aggregates. See 5028** [sqlite3_create_function()] and [sqlite3_create_function16()] 5029** for additional information. 5030** 5031** These functions work very much like the [parameter binding] family of 5032** functions used to bind values to host parameters in prepared statements. 5033** Refer to the [SQL parameter] documentation for additional information. 5034** 5035** ^The sqlite3_result_blob() interface sets the result from 5036** an application-defined function to be the BLOB whose content is pointed 5037** to by the second parameter and which is N bytes long where N is the 5038** third parameter. 5039** 5040** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5041** interfaces set the result of the application-defined function to be 5042** a BLOB containing all zero bytes and N bytes in size. 5043** 5044** ^The sqlite3_result_double() interface sets the result from 5045** an application-defined function to be a floating point value specified 5046** by its 2nd argument. 5047** 5048** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5049** cause the implemented SQL function to throw an exception. 5050** ^SQLite uses the string pointed to by the 5051** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5052** as the text of an error message. ^SQLite interprets the error 5053** message string from sqlite3_result_error() as UTF-8. ^SQLite 5054** interprets the string from sqlite3_result_error16() as UTF-16 in native 5055** byte order. ^If the third parameter to sqlite3_result_error() 5056** or sqlite3_result_error16() is negative then SQLite takes as the error 5057** message all text up through the first zero character. 5058** ^If the third parameter to sqlite3_result_error() or 5059** sqlite3_result_error16() is non-negative then SQLite takes that many 5060** bytes (not characters) from the 2nd parameter as the error message. 5061** ^The sqlite3_result_error() and sqlite3_result_error16() 5062** routines make a private copy of the error message text before 5063** they return. Hence, the calling function can deallocate or 5064** modify the text after they return without harm. 5065** ^The sqlite3_result_error_code() function changes the error code 5066** returned by SQLite as a result of an error in a function. ^By default, 5067** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5068** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5069** 5070** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5071** error indicating that a string or BLOB is too long to represent. 5072** 5073** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5074** error indicating that a memory allocation failed. 5075** 5076** ^The sqlite3_result_int() interface sets the return value 5077** of the application-defined function to be the 32-bit signed integer 5078** value given in the 2nd argument. 5079** ^The sqlite3_result_int64() interface sets the return value 5080** of the application-defined function to be the 64-bit signed integer 5081** value given in the 2nd argument. 5082** 5083** ^The sqlite3_result_null() interface sets the return value 5084** of the application-defined function to be NULL. 5085** 5086** ^The sqlite3_result_text(), sqlite3_result_text16(), 5087** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5088** set the return value of the application-defined function to be 5089** a text string which is represented as UTF-8, UTF-16 native byte order, 5090** UTF-16 little endian, or UTF-16 big endian, respectively. 5091** ^The sqlite3_result_text64() interface sets the return value of an 5092** application-defined function to be a text string in an encoding 5093** specified by the fifth (and last) parameter, which must be one 5094** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5095** ^SQLite takes the text result from the application from 5096** the 2nd parameter of the sqlite3_result_text* interfaces. 5097** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5098** is negative, then SQLite takes result text from the 2nd parameter 5099** through the first zero character. 5100** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5101** is non-negative, then as many bytes (not characters) of the text 5102** pointed to by the 2nd parameter are taken as the application-defined 5103** function result. If the 3rd parameter is non-negative, then it 5104** must be the byte offset into the string where the NUL terminator would 5105** appear if the string where NUL terminated. If any NUL characters occur 5106** in the string at a byte offset that is less than the value of the 3rd 5107** parameter, then the resulting string will contain embedded NULs and the 5108** result of expressions operating on strings with embedded NULs is undefined. 5109** ^If the 4th parameter to the sqlite3_result_text* interfaces 5110** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5111** function as the destructor on the text or BLOB result when it has 5112** finished using that result. 5113** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5114** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5115** assumes that the text or BLOB result is in constant space and does not 5116** copy the content of the parameter nor call a destructor on the content 5117** when it has finished using that result. 5118** ^If the 4th parameter to the sqlite3_result_text* interfaces 5119** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5120** then SQLite makes a copy of the result into space obtained 5121** from [sqlite3_malloc()] before it returns. 5122** 5123** ^The sqlite3_result_value() interface sets the result of 5124** the application-defined function to be a copy of the 5125** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5126** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5127** so that the [sqlite3_value] specified in the parameter may change or 5128** be deallocated after sqlite3_result_value() returns without harm. 5129** ^A [protected sqlite3_value] object may always be used where an 5130** [unprotected sqlite3_value] object is required, so either 5131** kind of [sqlite3_value] object can be used with this interface. 5132** 5133** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5134** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5135** also associates the host-language pointer P or type T with that 5136** NULL value such that the pointer can be retrieved within an 5137** [application-defined SQL function] using [sqlite3_value_pointer()]. 5138** ^If the D parameter is not NULL, then it is a pointer to a destructor 5139** for the P parameter. ^SQLite invokes D with P as its only argument 5140** when SQLite is finished with P. The T parameter should be a static 5141** string and preferably a string literal. The sqlite3_result_pointer() 5142** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5143** 5144** If these routines are called from within the different thread 5145** than the one containing the application-defined function that received 5146** the [sqlite3_context] pointer, the results are undefined. 5147*/ 5148void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5149void sqlite3_result_blob64(sqlite3_context*,const void*, 5150 sqlite3_uint64,void(*)(void*)); 5151void sqlite3_result_double(sqlite3_context*, double); 5152void sqlite3_result_error(sqlite3_context*, const char*, int); 5153void sqlite3_result_error16(sqlite3_context*, const void*, int); 5154void sqlite3_result_error_toobig(sqlite3_context*); 5155void sqlite3_result_error_nomem(sqlite3_context*); 5156void sqlite3_result_error_code(sqlite3_context*, int); 5157void sqlite3_result_int(sqlite3_context*, int); 5158void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5159void sqlite3_result_null(sqlite3_context*); 5160void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5161void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5162 void(*)(void*), unsigned char encoding); 5163void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5164void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5165void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5166void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5167void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5168void sqlite3_result_zeroblob(sqlite3_context*, int n); 5169int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5170 5171 5172/* 5173** CAPI3REF: Setting The Subtype Of An SQL Function 5174** METHOD: sqlite3_context 5175** 5176** The sqlite3_result_subtype(C,T) function causes the subtype of 5177** the result from the [application-defined SQL function] with 5178** [sqlite3_context] C to be the value T. Only the lower 8 bits 5179** of the subtype T are preserved in current versions of SQLite; 5180** higher order bits are discarded. 5181** The number of subtype bytes preserved by SQLite might increase 5182** in future releases of SQLite. 5183*/ 5184void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5185 5186/* 5187** CAPI3REF: Define New Collating Sequences 5188** METHOD: sqlite3 5189** 5190** ^These functions add, remove, or modify a [collation] associated 5191** with the [database connection] specified as the first argument. 5192** 5193** ^The name of the collation is a UTF-8 string 5194** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5195** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5196** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5197** considered to be the same name. 5198** 5199** ^(The third argument (eTextRep) must be one of the constants: 5200** <ul> 5201** <li> [SQLITE_UTF8], 5202** <li> [SQLITE_UTF16LE], 5203** <li> [SQLITE_UTF16BE], 5204** <li> [SQLITE_UTF16], or 5205** <li> [SQLITE_UTF16_ALIGNED]. 5206** </ul>)^ 5207** ^The eTextRep argument determines the encoding of strings passed 5208** to the collating function callback, xCallback. 5209** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5210** force strings to be UTF16 with native byte order. 5211** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5212** on an even byte address. 5213** 5214** ^The fourth argument, pArg, is an application data pointer that is passed 5215** through as the first argument to the collating function callback. 5216** 5217** ^The fifth argument, xCallback, is a pointer to the collating function. 5218** ^Multiple collating functions can be registered using the same name but 5219** with different eTextRep parameters and SQLite will use whichever 5220** function requires the least amount of data transformation. 5221** ^If the xCallback argument is NULL then the collating function is 5222** deleted. ^When all collating functions having the same name are deleted, 5223** that collation is no longer usable. 5224** 5225** ^The collating function callback is invoked with a copy of the pArg 5226** application data pointer and with two strings in the encoding specified 5227** by the eTextRep argument. The collating function must return an 5228** integer that is negative, zero, or positive 5229** if the first string is less than, equal to, or greater than the second, 5230** respectively. A collating function must always return the same answer 5231** given the same inputs. If two or more collating functions are registered 5232** to the same collation name (using different eTextRep values) then all 5233** must give an equivalent answer when invoked with equivalent strings. 5234** The collating function must obey the following properties for all 5235** strings A, B, and C: 5236** 5237** <ol> 5238** <li> If A==B then B==A. 5239** <li> If A==B and B==C then A==C. 5240** <li> If A<B THEN B>A. 5241** <li> If A<B and B<C then A<C. 5242** </ol> 5243** 5244** If a collating function fails any of the above constraints and that 5245** collating function is registered and used, then the behavior of SQLite 5246** is undefined. 5247** 5248** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5249** with the addition that the xDestroy callback is invoked on pArg when 5250** the collating function is deleted. 5251** ^Collating functions are deleted when they are overridden by later 5252** calls to the collation creation functions or when the 5253** [database connection] is closed using [sqlite3_close()]. 5254** 5255** ^The xDestroy callback is <u>not</u> called if the 5256** sqlite3_create_collation_v2() function fails. Applications that invoke 5257** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5258** check the return code and dispose of the application data pointer 5259** themselves rather than expecting SQLite to deal with it for them. 5260** This is different from every other SQLite interface. The inconsistency 5261** is unfortunate but cannot be changed without breaking backwards 5262** compatibility. 5263** 5264** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5265*/ 5266int sqlite3_create_collation( 5267 sqlite3*, 5268 const char *zName, 5269 int eTextRep, 5270 void *pArg, 5271 int(*xCompare)(void*,int,const void*,int,const void*) 5272); 5273int sqlite3_create_collation_v2( 5274 sqlite3*, 5275 const char *zName, 5276 int eTextRep, 5277 void *pArg, 5278 int(*xCompare)(void*,int,const void*,int,const void*), 5279 void(*xDestroy)(void*) 5280); 5281int sqlite3_create_collation16( 5282 sqlite3*, 5283 const void *zName, 5284 int eTextRep, 5285 void *pArg, 5286 int(*xCompare)(void*,int,const void*,int,const void*) 5287); 5288 5289/* 5290** CAPI3REF: Collation Needed Callbacks 5291** METHOD: sqlite3 5292** 5293** ^To avoid having to register all collation sequences before a database 5294** can be used, a single callback function may be registered with the 5295** [database connection] to be invoked whenever an undefined collation 5296** sequence is required. 5297** 5298** ^If the function is registered using the sqlite3_collation_needed() API, 5299** then it is passed the names of undefined collation sequences as strings 5300** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5301** the names are passed as UTF-16 in machine native byte order. 5302** ^A call to either function replaces the existing collation-needed callback. 5303** 5304** ^(When the callback is invoked, the first argument passed is a copy 5305** of the second argument to sqlite3_collation_needed() or 5306** sqlite3_collation_needed16(). The second argument is the database 5307** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5308** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5309** sequence function required. The fourth parameter is the name of the 5310** required collation sequence.)^ 5311** 5312** The callback function should register the desired collation using 5313** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5314** [sqlite3_create_collation_v2()]. 5315*/ 5316int sqlite3_collation_needed( 5317 sqlite3*, 5318 void*, 5319 void(*)(void*,sqlite3*,int eTextRep,const char*) 5320); 5321int sqlite3_collation_needed16( 5322 sqlite3*, 5323 void*, 5324 void(*)(void*,sqlite3*,int eTextRep,const void*) 5325); 5326 5327#ifdef SQLITE_HAS_CODEC 5328/* 5329** Specify the key for an encrypted database. This routine should be 5330** called right after sqlite3_open(). 5331** 5332** The code to implement this API is not available in the public release 5333** of SQLite. 5334*/ 5335int sqlite3_key( 5336 sqlite3 *db, /* Database to be rekeyed */ 5337 const void *pKey, int nKey /* The key */ 5338); 5339int sqlite3_key_v2( 5340 sqlite3 *db, /* Database to be rekeyed */ 5341 const char *zDbName, /* Name of the database */ 5342 const void *pKey, int nKey /* The key */ 5343); 5344 5345/* 5346** Change the key on an open database. If the current database is not 5347** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5348** database is decrypted. 5349** 5350** The code to implement this API is not available in the public release 5351** of SQLite. 5352*/ 5353int sqlite3_rekey( 5354 sqlite3 *db, /* Database to be rekeyed */ 5355 const void *pKey, int nKey /* The new key */ 5356); 5357int sqlite3_rekey_v2( 5358 sqlite3 *db, /* Database to be rekeyed */ 5359 const char *zDbName, /* Name of the database */ 5360 const void *pKey, int nKey /* The new key */ 5361); 5362 5363/* 5364** Specify the activation key for a SEE database. Unless 5365** activated, none of the SEE routines will work. 5366*/ 5367void sqlite3_activate_see( 5368 const char *zPassPhrase /* Activation phrase */ 5369); 5370#endif 5371 5372#ifdef SQLITE_ENABLE_CEROD 5373/* 5374** Specify the activation key for a CEROD database. Unless 5375** activated, none of the CEROD routines will work. 5376*/ 5377void sqlite3_activate_cerod( 5378 const char *zPassPhrase /* Activation phrase */ 5379); 5380#endif 5381 5382/* 5383** CAPI3REF: Suspend Execution For A Short Time 5384** 5385** The sqlite3_sleep() function causes the current thread to suspend execution 5386** for at least a number of milliseconds specified in its parameter. 5387** 5388** If the operating system does not support sleep requests with 5389** millisecond time resolution, then the time will be rounded up to 5390** the nearest second. The number of milliseconds of sleep actually 5391** requested from the operating system is returned. 5392** 5393** ^SQLite implements this interface by calling the xSleep() 5394** method of the default [sqlite3_vfs] object. If the xSleep() method 5395** of the default VFS is not implemented correctly, or not implemented at 5396** all, then the behavior of sqlite3_sleep() may deviate from the description 5397** in the previous paragraphs. 5398*/ 5399int sqlite3_sleep(int); 5400 5401/* 5402** CAPI3REF: Name Of The Folder Holding Temporary Files 5403** 5404** ^(If this global variable is made to point to a string which is 5405** the name of a folder (a.k.a. directory), then all temporary files 5406** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5407** will be placed in that directory.)^ ^If this variable 5408** is a NULL pointer, then SQLite performs a search for an appropriate 5409** temporary file directory. 5410** 5411** Applications are strongly discouraged from using this global variable. 5412** It is required to set a temporary folder on Windows Runtime (WinRT). 5413** But for all other platforms, it is highly recommended that applications 5414** neither read nor write this variable. This global variable is a relic 5415** that exists for backwards compatibility of legacy applications and should 5416** be avoided in new projects. 5417** 5418** It is not safe to read or modify this variable in more than one 5419** thread at a time. It is not safe to read or modify this variable 5420** if a [database connection] is being used at the same time in a separate 5421** thread. 5422** It is intended that this variable be set once 5423** as part of process initialization and before any SQLite interface 5424** routines have been called and that this variable remain unchanged 5425** thereafter. 5426** 5427** ^The [temp_store_directory pragma] may modify this variable and cause 5428** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5429** the [temp_store_directory pragma] always assumes that any string 5430** that this variable points to is held in memory obtained from 5431** [sqlite3_malloc] and the pragma may attempt to free that memory 5432** using [sqlite3_free]. 5433** Hence, if this variable is modified directly, either it should be 5434** made NULL or made to point to memory obtained from [sqlite3_malloc] 5435** or else the use of the [temp_store_directory pragma] should be avoided. 5436** Except when requested by the [temp_store_directory pragma], SQLite 5437** does not free the memory that sqlite3_temp_directory points to. If 5438** the application wants that memory to be freed, it must do 5439** so itself, taking care to only do so after all [database connection] 5440** objects have been destroyed. 5441** 5442** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5443** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5444** features that require the use of temporary files may fail. Here is an 5445** example of how to do this using C++ with the Windows Runtime: 5446** 5447** <blockquote><pre> 5448** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5449** TemporaryFolder->Path->Data(); 5450** char zPathBuf[MAX_PATH + 1]; 5451** memset(zPathBuf, 0, sizeof(zPathBuf)); 5452** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5453** NULL, NULL); 5454** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5455** </pre></blockquote> 5456*/ 5457SQLITE_EXTERN char *sqlite3_temp_directory; 5458 5459/* 5460** CAPI3REF: Name Of The Folder Holding Database Files 5461** 5462** ^(If this global variable is made to point to a string which is 5463** the name of a folder (a.k.a. directory), then all database files 5464** specified with a relative pathname and created or accessed by 5465** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5466** to be relative to that directory.)^ ^If this variable is a NULL 5467** pointer, then SQLite assumes that all database files specified 5468** with a relative pathname are relative to the current directory 5469** for the process. Only the windows VFS makes use of this global 5470** variable; it is ignored by the unix VFS. 5471** 5472** Changing the value of this variable while a database connection is 5473** open can result in a corrupt database. 5474** 5475** It is not safe to read or modify this variable in more than one 5476** thread at a time. It is not safe to read or modify this variable 5477** if a [database connection] is being used at the same time in a separate 5478** thread. 5479** It is intended that this variable be set once 5480** as part of process initialization and before any SQLite interface 5481** routines have been called and that this variable remain unchanged 5482** thereafter. 5483** 5484** ^The [data_store_directory pragma] may modify this variable and cause 5485** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5486** the [data_store_directory pragma] always assumes that any string 5487** that this variable points to is held in memory obtained from 5488** [sqlite3_malloc] and the pragma may attempt to free that memory 5489** using [sqlite3_free]. 5490** Hence, if this variable is modified directly, either it should be 5491** made NULL or made to point to memory obtained from [sqlite3_malloc] 5492** or else the use of the [data_store_directory pragma] should be avoided. 5493*/ 5494SQLITE_EXTERN char *sqlite3_data_directory; 5495 5496/* 5497** CAPI3REF: Test For Auto-Commit Mode 5498** KEYWORDS: {autocommit mode} 5499** METHOD: sqlite3 5500** 5501** ^The sqlite3_get_autocommit() interface returns non-zero or 5502** zero if the given database connection is or is not in autocommit mode, 5503** respectively. ^Autocommit mode is on by default. 5504** ^Autocommit mode is disabled by a [BEGIN] statement. 5505** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5506** 5507** If certain kinds of errors occur on a statement within a multi-statement 5508** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5509** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5510** transaction might be rolled back automatically. The only way to 5511** find out whether SQLite automatically rolled back the transaction after 5512** an error is to use this function. 5513** 5514** If another thread changes the autocommit status of the database 5515** connection while this routine is running, then the return value 5516** is undefined. 5517*/ 5518int sqlite3_get_autocommit(sqlite3*); 5519 5520/* 5521** CAPI3REF: Find The Database Handle Of A Prepared Statement 5522** METHOD: sqlite3_stmt 5523** 5524** ^The sqlite3_db_handle interface returns the [database connection] handle 5525** to which a [prepared statement] belongs. ^The [database connection] 5526** returned by sqlite3_db_handle is the same [database connection] 5527** that was the first argument 5528** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5529** create the statement in the first place. 5530*/ 5531sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5532 5533/* 5534** CAPI3REF: Return The Filename For A Database Connection 5535** METHOD: sqlite3 5536** 5537** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5538** associated with database N of connection D. ^The main database file 5539** has the name "main". If there is no attached database N on the database 5540** connection D, or if database N is a temporary or in-memory database, then 5541** a NULL pointer is returned. 5542** 5543** ^The filename returned by this function is the output of the 5544** xFullPathname method of the [VFS]. ^In other words, the filename 5545** will be an absolute pathname, even if the filename used 5546** to open the database originally was a URI or relative pathname. 5547*/ 5548const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5549 5550/* 5551** CAPI3REF: Determine if a database is read-only 5552** METHOD: sqlite3 5553** 5554** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5555** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5556** the name of a database on connection D. 5557*/ 5558int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5559 5560/* 5561** CAPI3REF: Find the next prepared statement 5562** METHOD: sqlite3 5563** 5564** ^This interface returns a pointer to the next [prepared statement] after 5565** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5566** then this interface returns a pointer to the first prepared statement 5567** associated with the database connection pDb. ^If no prepared statement 5568** satisfies the conditions of this routine, it returns NULL. 5569** 5570** The [database connection] pointer D in a call to 5571** [sqlite3_next_stmt(D,S)] must refer to an open database 5572** connection and in particular must not be a NULL pointer. 5573*/ 5574sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5575 5576/* 5577** CAPI3REF: Commit And Rollback Notification Callbacks 5578** METHOD: sqlite3 5579** 5580** ^The sqlite3_commit_hook() interface registers a callback 5581** function to be invoked whenever a transaction is [COMMIT | committed]. 5582** ^Any callback set by a previous call to sqlite3_commit_hook() 5583** for the same database connection is overridden. 5584** ^The sqlite3_rollback_hook() interface registers a callback 5585** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5586** ^Any callback set by a previous call to sqlite3_rollback_hook() 5587** for the same database connection is overridden. 5588** ^The pArg argument is passed through to the callback. 5589** ^If the callback on a commit hook function returns non-zero, 5590** then the commit is converted into a rollback. 5591** 5592** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5593** return the P argument from the previous call of the same function 5594** on the same [database connection] D, or NULL for 5595** the first call for each function on D. 5596** 5597** The commit and rollback hook callbacks are not reentrant. 5598** The callback implementation must not do anything that will modify 5599** the database connection that invoked the callback. Any actions 5600** to modify the database connection must be deferred until after the 5601** completion of the [sqlite3_step()] call that triggered the commit 5602** or rollback hook in the first place. 5603** Note that running any other SQL statements, including SELECT statements, 5604** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5605** the database connections for the meaning of "modify" in this paragraph. 5606** 5607** ^Registering a NULL function disables the callback. 5608** 5609** ^When the commit hook callback routine returns zero, the [COMMIT] 5610** operation is allowed to continue normally. ^If the commit hook 5611** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5612** ^The rollback hook is invoked on a rollback that results from a commit 5613** hook returning non-zero, just as it would be with any other rollback. 5614** 5615** ^For the purposes of this API, a transaction is said to have been 5616** rolled back if an explicit "ROLLBACK" statement is executed, or 5617** an error or constraint causes an implicit rollback to occur. 5618** ^The rollback callback is not invoked if a transaction is 5619** automatically rolled back because the database connection is closed. 5620** 5621** See also the [sqlite3_update_hook()] interface. 5622*/ 5623void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5624void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5625 5626/* 5627** CAPI3REF: Data Change Notification Callbacks 5628** METHOD: sqlite3 5629** 5630** ^The sqlite3_update_hook() interface registers a callback function 5631** with the [database connection] identified by the first argument 5632** to be invoked whenever a row is updated, inserted or deleted in 5633** a [rowid table]. 5634** ^Any callback set by a previous call to this function 5635** for the same database connection is overridden. 5636** 5637** ^The second argument is a pointer to the function to invoke when a 5638** row is updated, inserted or deleted in a rowid table. 5639** ^The first argument to the callback is a copy of the third argument 5640** to sqlite3_update_hook(). 5641** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5642** or [SQLITE_UPDATE], depending on the operation that caused the callback 5643** to be invoked. 5644** ^The third and fourth arguments to the callback contain pointers to the 5645** database and table name containing the affected row. 5646** ^The final callback parameter is the [rowid] of the row. 5647** ^In the case of an update, this is the [rowid] after the update takes place. 5648** 5649** ^(The update hook is not invoked when internal system tables are 5650** modified (i.e. sqlite_master and sqlite_sequence).)^ 5651** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5652** 5653** ^In the current implementation, the update hook 5654** is not invoked when conflicting rows are deleted because of an 5655** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5656** invoked when rows are deleted using the [truncate optimization]. 5657** The exceptions defined in this paragraph might change in a future 5658** release of SQLite. 5659** 5660** The update hook implementation must not do anything that will modify 5661** the database connection that invoked the update hook. Any actions 5662** to modify the database connection must be deferred until after the 5663** completion of the [sqlite3_step()] call that triggered the update hook. 5664** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5665** database connections for the meaning of "modify" in this paragraph. 5666** 5667** ^The sqlite3_update_hook(D,C,P) function 5668** returns the P argument from the previous call 5669** on the same [database connection] D, or NULL for 5670** the first call on D. 5671** 5672** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5673** and [sqlite3_preupdate_hook()] interfaces. 5674*/ 5675void *sqlite3_update_hook( 5676 sqlite3*, 5677 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5678 void* 5679); 5680 5681/* 5682** CAPI3REF: Enable Or Disable Shared Pager Cache 5683** 5684** ^(This routine enables or disables the sharing of the database cache 5685** and schema data structures between [database connection | connections] 5686** to the same database. Sharing is enabled if the argument is true 5687** and disabled if the argument is false.)^ 5688** 5689** ^Cache sharing is enabled and disabled for an entire process. 5690** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5691** In prior versions of SQLite, 5692** sharing was enabled or disabled for each thread separately. 5693** 5694** ^(The cache sharing mode set by this interface effects all subsequent 5695** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5696** Existing database connections continue use the sharing mode 5697** that was in effect at the time they were opened.)^ 5698** 5699** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5700** successfully. An [error code] is returned otherwise.)^ 5701** 5702** ^Shared cache is disabled by default. But this might change in 5703** future releases of SQLite. Applications that care about shared 5704** cache setting should set it explicitly. 5705** 5706** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5707** and will always return SQLITE_MISUSE. On those systems, 5708** shared cache mode should be enabled per-database connection via 5709** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5710** 5711** This interface is threadsafe on processors where writing a 5712** 32-bit integer is atomic. 5713** 5714** See Also: [SQLite Shared-Cache Mode] 5715*/ 5716int sqlite3_enable_shared_cache(int); 5717 5718/* 5719** CAPI3REF: Attempt To Free Heap Memory 5720** 5721** ^The sqlite3_release_memory() interface attempts to free N bytes 5722** of heap memory by deallocating non-essential memory allocations 5723** held by the database library. Memory used to cache database 5724** pages to improve performance is an example of non-essential memory. 5725** ^sqlite3_release_memory() returns the number of bytes actually freed, 5726** which might be more or less than the amount requested. 5727** ^The sqlite3_release_memory() routine is a no-op returning zero 5728** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5729** 5730** See also: [sqlite3_db_release_memory()] 5731*/ 5732int sqlite3_release_memory(int); 5733 5734/* 5735** CAPI3REF: Free Memory Used By A Database Connection 5736** METHOD: sqlite3 5737** 5738** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 5739** memory as possible from database connection D. Unlike the 5740** [sqlite3_release_memory()] interface, this interface is in effect even 5741** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 5742** omitted. 5743** 5744** See also: [sqlite3_release_memory()] 5745*/ 5746int sqlite3_db_release_memory(sqlite3*); 5747 5748/* 5749** CAPI3REF: Impose A Limit On Heap Size 5750** 5751** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 5752** soft limit on the amount of heap memory that may be allocated by SQLite. 5753** ^SQLite strives to keep heap memory utilization below the soft heap 5754** limit by reducing the number of pages held in the page cache 5755** as heap memory usages approaches the limit. 5756** ^The soft heap limit is "soft" because even though SQLite strives to stay 5757** below the limit, it will exceed the limit rather than generate 5758** an [SQLITE_NOMEM] error. In other words, the soft heap limit 5759** is advisory only. 5760** 5761** ^The return value from sqlite3_soft_heap_limit64() is the size of 5762** the soft heap limit prior to the call, or negative in the case of an 5763** error. ^If the argument N is negative 5764** then no change is made to the soft heap limit. Hence, the current 5765** size of the soft heap limit can be determined by invoking 5766** sqlite3_soft_heap_limit64() with a negative argument. 5767** 5768** ^If the argument N is zero then the soft heap limit is disabled. 5769** 5770** ^(The soft heap limit is not enforced in the current implementation 5771** if one or more of following conditions are true: 5772** 5773** <ul> 5774** <li> The soft heap limit is set to zero. 5775** <li> Memory accounting is disabled using a combination of the 5776** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 5777** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 5778** <li> An alternative page cache implementation is specified using 5779** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 5780** <li> The page cache allocates from its own memory pool supplied 5781** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 5782** from the heap. 5783** </ul>)^ 5784** 5785** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 5786** the soft heap limit is enforced 5787** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 5788** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 5789** the soft heap limit is enforced on every memory allocation. Without 5790** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 5791** when memory is allocated by the page cache. Testing suggests that because 5792** the page cache is the predominate memory user in SQLite, most 5793** applications will achieve adequate soft heap limit enforcement without 5794** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5795** 5796** The circumstances under which SQLite will enforce the soft heap limit may 5797** changes in future releases of SQLite. 5798*/ 5799sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 5800 5801/* 5802** CAPI3REF: Deprecated Soft Heap Limit Interface 5803** DEPRECATED 5804** 5805** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 5806** interface. This routine is provided for historical compatibility 5807** only. All new applications should use the 5808** [sqlite3_soft_heap_limit64()] interface rather than this one. 5809*/ 5810SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 5811 5812 5813/* 5814** CAPI3REF: Extract Metadata About A Column Of A Table 5815** METHOD: sqlite3 5816** 5817** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 5818** information about column C of table T in database D 5819** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 5820** interface returns SQLITE_OK and fills in the non-NULL pointers in 5821** the final five arguments with appropriate values if the specified 5822** column exists. ^The sqlite3_table_column_metadata() interface returns 5823** SQLITE_ERROR and if the specified column does not exist. 5824** ^If the column-name parameter to sqlite3_table_column_metadata() is a 5825** NULL pointer, then this routine simply checks for the existence of the 5826** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 5827** does not. If the table name parameter T in a call to 5828** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 5829** undefined behavior. 5830** 5831** ^The column is identified by the second, third and fourth parameters to 5832** this function. ^(The second parameter is either the name of the database 5833** (i.e. "main", "temp", or an attached database) containing the specified 5834** table or NULL.)^ ^If it is NULL, then all attached databases are searched 5835** for the table using the same algorithm used by the database engine to 5836** resolve unqualified table references. 5837** 5838** ^The third and fourth parameters to this function are the table and column 5839** name of the desired column, respectively. 5840** 5841** ^Metadata is returned by writing to the memory locations passed as the 5th 5842** and subsequent parameters to this function. ^Any of these arguments may be 5843** NULL, in which case the corresponding element of metadata is omitted. 5844** 5845** ^(<blockquote> 5846** <table border="1"> 5847** <tr><th> Parameter <th> Output<br>Type <th> Description 5848** 5849** <tr><td> 5th <td> const char* <td> Data type 5850** <tr><td> 6th <td> const char* <td> Name of default collation sequence 5851** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 5852** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 5853** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 5854** </table> 5855** </blockquote>)^ 5856** 5857** ^The memory pointed to by the character pointers returned for the 5858** declaration type and collation sequence is valid until the next 5859** call to any SQLite API function. 5860** 5861** ^If the specified table is actually a view, an [error code] is returned. 5862** 5863** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 5864** is not a [WITHOUT ROWID] table and an 5865** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 5866** parameters are set for the explicitly declared column. ^(If there is no 5867** [INTEGER PRIMARY KEY] column, then the outputs 5868** for the [rowid] are set as follows: 5869** 5870** <pre> 5871** data type: "INTEGER" 5872** collation sequence: "BINARY" 5873** not null: 0 5874** primary key: 1 5875** auto increment: 0 5876** </pre>)^ 5877** 5878** ^This function causes all database schemas to be read from disk and 5879** parsed, if that has not already been done, and returns an error if 5880** any errors are encountered while loading the schema. 5881*/ 5882int sqlite3_table_column_metadata( 5883 sqlite3 *db, /* Connection handle */ 5884 const char *zDbName, /* Database name or NULL */ 5885 const char *zTableName, /* Table name */ 5886 const char *zColumnName, /* Column name */ 5887 char const **pzDataType, /* OUTPUT: Declared data type */ 5888 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 5889 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 5890 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 5891 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 5892); 5893 5894/* 5895** CAPI3REF: Load An Extension 5896** METHOD: sqlite3 5897** 5898** ^This interface loads an SQLite extension library from the named file. 5899** 5900** ^The sqlite3_load_extension() interface attempts to load an 5901** [SQLite extension] library contained in the file zFile. If 5902** the file cannot be loaded directly, attempts are made to load 5903** with various operating-system specific extensions added. 5904** So for example, if "samplelib" cannot be loaded, then names like 5905** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 5906** be tried also. 5907** 5908** ^The entry point is zProc. 5909** ^(zProc may be 0, in which case SQLite will try to come up with an 5910** entry point name on its own. It first tries "sqlite3_extension_init". 5911** If that does not work, it constructs a name "sqlite3_X_init" where the 5912** X is consists of the lower-case equivalent of all ASCII alphabetic 5913** characters in the filename from the last "/" to the first following 5914** "." and omitting any initial "lib".)^ 5915** ^The sqlite3_load_extension() interface returns 5916** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 5917** ^If an error occurs and pzErrMsg is not 0, then the 5918** [sqlite3_load_extension()] interface shall attempt to 5919** fill *pzErrMsg with error message text stored in memory 5920** obtained from [sqlite3_malloc()]. The calling function 5921** should free this memory by calling [sqlite3_free()]. 5922** 5923** ^Extension loading must be enabled using 5924** [sqlite3_enable_load_extension()] or 5925** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 5926** prior to calling this API, 5927** otherwise an error will be returned. 5928** 5929** <b>Security warning:</b> It is recommended that the 5930** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 5931** interface. The use of the [sqlite3_enable_load_extension()] interface 5932** should be avoided. This will keep the SQL function [load_extension()] 5933** disabled and prevent SQL injections from giving attackers 5934** access to extension loading capabilities. 5935** 5936** See also the [load_extension() SQL function]. 5937*/ 5938int sqlite3_load_extension( 5939 sqlite3 *db, /* Load the extension into this database connection */ 5940 const char *zFile, /* Name of the shared library containing extension */ 5941 const char *zProc, /* Entry point. Derived from zFile if 0 */ 5942 char **pzErrMsg /* Put error message here if not 0 */ 5943); 5944 5945/* 5946** CAPI3REF: Enable Or Disable Extension Loading 5947** METHOD: sqlite3 5948** 5949** ^So as not to open security holes in older applications that are 5950** unprepared to deal with [extension loading], and as a means of disabling 5951** [extension loading] while evaluating user-entered SQL, the following API 5952** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 5953** 5954** ^Extension loading is off by default. 5955** ^Call the sqlite3_enable_load_extension() routine with onoff==1 5956** to turn extension loading on and call it with onoff==0 to turn 5957** it back off again. 5958** 5959** ^This interface enables or disables both the C-API 5960** [sqlite3_load_extension()] and the SQL function [load_extension()]. 5961** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 5962** to enable or disable only the C-API.)^ 5963** 5964** <b>Security warning:</b> It is recommended that extension loading 5965** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 5966** rather than this interface, so the [load_extension()] SQL function 5967** remains disabled. This will prevent SQL injections from giving attackers 5968** access to extension loading capabilities. 5969*/ 5970int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 5971 5972/* 5973** CAPI3REF: Automatically Load Statically Linked Extensions 5974** 5975** ^This interface causes the xEntryPoint() function to be invoked for 5976** each new [database connection] that is created. The idea here is that 5977** xEntryPoint() is the entry point for a statically linked [SQLite extension] 5978** that is to be automatically loaded into all new database connections. 5979** 5980** ^(Even though the function prototype shows that xEntryPoint() takes 5981** no arguments and returns void, SQLite invokes xEntryPoint() with three 5982** arguments and expects an integer result as if the signature of the 5983** entry point where as follows: 5984** 5985** <blockquote><pre> 5986** int xEntryPoint( 5987** sqlite3 *db, 5988** const char **pzErrMsg, 5989** const struct sqlite3_api_routines *pThunk 5990** ); 5991** </pre></blockquote>)^ 5992** 5993** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 5994** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 5995** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 5996** is NULL before calling the xEntryPoint(). ^SQLite will invoke 5997** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 5998** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 5999** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6000** 6001** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6002** on the list of automatic extensions is a harmless no-op. ^No entry point 6003** will be called more than once for each database connection that is opened. 6004** 6005** See also: [sqlite3_reset_auto_extension()] 6006** and [sqlite3_cancel_auto_extension()] 6007*/ 6008int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6009 6010/* 6011** CAPI3REF: Cancel Automatic Extension Loading 6012** 6013** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6014** initialization routine X that was registered using a prior call to 6015** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6016** routine returns 1 if initialization routine X was successfully 6017** unregistered and it returns 0 if X was not on the list of initialization 6018** routines. 6019*/ 6020int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6021 6022/* 6023** CAPI3REF: Reset Automatic Extension Loading 6024** 6025** ^This interface disables all automatic extensions previously 6026** registered using [sqlite3_auto_extension()]. 6027*/ 6028void sqlite3_reset_auto_extension(void); 6029 6030/* 6031** The interface to the virtual-table mechanism is currently considered 6032** to be experimental. The interface might change in incompatible ways. 6033** If this is a problem for you, do not use the interface at this time. 6034** 6035** When the virtual-table mechanism stabilizes, we will declare the 6036** interface fixed, support it indefinitely, and remove this comment. 6037*/ 6038 6039/* 6040** Structures used by the virtual table interface 6041*/ 6042typedef struct sqlite3_vtab sqlite3_vtab; 6043typedef struct sqlite3_index_info sqlite3_index_info; 6044typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6045typedef struct sqlite3_module sqlite3_module; 6046 6047/* 6048** CAPI3REF: Virtual Table Object 6049** KEYWORDS: sqlite3_module {virtual table module} 6050** 6051** This structure, sometimes called a "virtual table module", 6052** defines the implementation of a [virtual tables]. 6053** This structure consists mostly of methods for the module. 6054** 6055** ^A virtual table module is created by filling in a persistent 6056** instance of this structure and passing a pointer to that instance 6057** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6058** ^The registration remains valid until it is replaced by a different 6059** module or until the [database connection] closes. The content 6060** of this structure must not change while it is registered with 6061** any database connection. 6062*/ 6063struct sqlite3_module { 6064 int iVersion; 6065 int (*xCreate)(sqlite3*, void *pAux, 6066 int argc, const char *const*argv, 6067 sqlite3_vtab **ppVTab, char**); 6068 int (*xConnect)(sqlite3*, void *pAux, 6069 int argc, const char *const*argv, 6070 sqlite3_vtab **ppVTab, char**); 6071 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6072 int (*xDisconnect)(sqlite3_vtab *pVTab); 6073 int (*xDestroy)(sqlite3_vtab *pVTab); 6074 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6075 int (*xClose)(sqlite3_vtab_cursor*); 6076 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6077 int argc, sqlite3_value **argv); 6078 int (*xNext)(sqlite3_vtab_cursor*); 6079 int (*xEof)(sqlite3_vtab_cursor*); 6080 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6081 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6082 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6083 int (*xBegin)(sqlite3_vtab *pVTab); 6084 int (*xSync)(sqlite3_vtab *pVTab); 6085 int (*xCommit)(sqlite3_vtab *pVTab); 6086 int (*xRollback)(sqlite3_vtab *pVTab); 6087 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6088 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6089 void **ppArg); 6090 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6091 /* The methods above are in version 1 of the sqlite_module object. Those 6092 ** below are for version 2 and greater. */ 6093 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6094 int (*xRelease)(sqlite3_vtab *pVTab, int); 6095 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6096}; 6097 6098/* 6099** CAPI3REF: Virtual Table Indexing Information 6100** KEYWORDS: sqlite3_index_info 6101** 6102** The sqlite3_index_info structure and its substructures is used as part 6103** of the [virtual table] interface to 6104** pass information into and receive the reply from the [xBestIndex] 6105** method of a [virtual table module]. The fields under **Inputs** are the 6106** inputs to xBestIndex and are read-only. xBestIndex inserts its 6107** results into the **Outputs** fields. 6108** 6109** ^(The aConstraint[] array records WHERE clause constraints of the form: 6110** 6111** <blockquote>column OP expr</blockquote> 6112** 6113** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6114** stored in aConstraint[].op using one of the 6115** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6116** ^(The index of the column is stored in 6117** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6118** expr on the right-hand side can be evaluated (and thus the constraint 6119** is usable) and false if it cannot.)^ 6120** 6121** ^The optimizer automatically inverts terms of the form "expr OP column" 6122** and makes other simplifications to the WHERE clause in an attempt to 6123** get as many WHERE clause terms into the form shown above as possible. 6124** ^The aConstraint[] array only reports WHERE clause terms that are 6125** relevant to the particular virtual table being queried. 6126** 6127** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6128** ^Each term of aOrderBy records a column of the ORDER BY clause. 6129** 6130** The colUsed field indicates which columns of the virtual table may be 6131** required by the current scan. Virtual table columns are numbered from 6132** zero in the order in which they appear within the CREATE TABLE statement 6133** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6134** the corresponding bit is set within the colUsed mask if the column may be 6135** required by SQLite. If the table has at least 64 columns and any column 6136** to the right of the first 63 is required, then bit 63 of colUsed is also 6137** set. In other words, column iCol may be required if the expression 6138** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6139** non-zero. 6140** 6141** The [xBestIndex] method must fill aConstraintUsage[] with information 6142** about what parameters to pass to xFilter. ^If argvIndex>0 then 6143** the right-hand side of the corresponding aConstraint[] is evaluated 6144** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6145** is true, then the constraint is assumed to be fully handled by the 6146** virtual table and is not checked again by SQLite.)^ 6147** 6148** ^The idxNum and idxPtr values are recorded and passed into the 6149** [xFilter] method. 6150** ^[sqlite3_free()] is used to free idxPtr if and only if 6151** needToFreeIdxPtr is true. 6152** 6153** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6154** the correct order to satisfy the ORDER BY clause so that no separate 6155** sorting step is required. 6156** 6157** ^The estimatedCost value is an estimate of the cost of a particular 6158** strategy. A cost of N indicates that the cost of the strategy is similar 6159** to a linear scan of an SQLite table with N rows. A cost of log(N) 6160** indicates that the expense of the operation is similar to that of a 6161** binary search on a unique indexed field of an SQLite table with N rows. 6162** 6163** ^The estimatedRows value is an estimate of the number of rows that 6164** will be returned by the strategy. 6165** 6166** The xBestIndex method may optionally populate the idxFlags field with a 6167** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6168** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6169** assumes that the strategy may visit at most one row. 6170** 6171** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6172** SQLite also assumes that if a call to the xUpdate() method is made as 6173** part of the same statement to delete or update a virtual table row and the 6174** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6175** any database changes. In other words, if the xUpdate() returns 6176** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6177** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6178** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6179** the xUpdate method are automatically rolled back by SQLite. 6180** 6181** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6182** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6183** If a virtual table extension is 6184** used with an SQLite version earlier than 3.8.2, the results of attempting 6185** to read or write the estimatedRows field are undefined (but are likely 6186** to included crashing the application). The estimatedRows field should 6187** therefore only be used if [sqlite3_libversion_number()] returns a 6188** value greater than or equal to 3008002. Similarly, the idxFlags field 6189** was added for [version 3.9.0] ([dateof:3.9.0]). 6190** It may therefore only be used if 6191** sqlite3_libversion_number() returns a value greater than or equal to 6192** 3009000. 6193*/ 6194struct sqlite3_index_info { 6195 /* Inputs */ 6196 int nConstraint; /* Number of entries in aConstraint */ 6197 struct sqlite3_index_constraint { 6198 int iColumn; /* Column constrained. -1 for ROWID */ 6199 unsigned char op; /* Constraint operator */ 6200 unsigned char usable; /* True if this constraint is usable */ 6201 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6202 } *aConstraint; /* Table of WHERE clause constraints */ 6203 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6204 struct sqlite3_index_orderby { 6205 int iColumn; /* Column number */ 6206 unsigned char desc; /* True for DESC. False for ASC. */ 6207 } *aOrderBy; /* The ORDER BY clause */ 6208 /* Outputs */ 6209 struct sqlite3_index_constraint_usage { 6210 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6211 unsigned char omit; /* Do not code a test for this constraint */ 6212 } *aConstraintUsage; 6213 int idxNum; /* Number used to identify the index */ 6214 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6215 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6216 int orderByConsumed; /* True if output is already ordered */ 6217 double estimatedCost; /* Estimated cost of using this index */ 6218 /* Fields below are only available in SQLite 3.8.2 and later */ 6219 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6220 /* Fields below are only available in SQLite 3.9.0 and later */ 6221 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6222 /* Fields below are only available in SQLite 3.10.0 and later */ 6223 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6224}; 6225 6226/* 6227** CAPI3REF: Virtual Table Scan Flags 6228*/ 6229#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6230 6231/* 6232** CAPI3REF: Virtual Table Constraint Operator Codes 6233** 6234** These macros defined the allowed values for the 6235** [sqlite3_index_info].aConstraint[].op field. Each value represents 6236** an operator that is part of a constraint term in the wHERE clause of 6237** a query that uses a [virtual table]. 6238*/ 6239#define SQLITE_INDEX_CONSTRAINT_EQ 2 6240#define SQLITE_INDEX_CONSTRAINT_GT 4 6241#define SQLITE_INDEX_CONSTRAINT_LE 8 6242#define SQLITE_INDEX_CONSTRAINT_LT 16 6243#define SQLITE_INDEX_CONSTRAINT_GE 32 6244#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6245#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6246#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6247#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6248#define SQLITE_INDEX_CONSTRAINT_NE 68 6249#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6250#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6251#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6252#define SQLITE_INDEX_CONSTRAINT_IS 72 6253 6254/* 6255** CAPI3REF: Register A Virtual Table Implementation 6256** METHOD: sqlite3 6257** 6258** ^These routines are used to register a new [virtual table module] name. 6259** ^Module names must be registered before 6260** creating a new [virtual table] using the module and before using a 6261** preexisting [virtual table] for the module. 6262** 6263** ^The module name is registered on the [database connection] specified 6264** by the first parameter. ^The name of the module is given by the 6265** second parameter. ^The third parameter is a pointer to 6266** the implementation of the [virtual table module]. ^The fourth 6267** parameter is an arbitrary client data pointer that is passed through 6268** into the [xCreate] and [xConnect] methods of the virtual table module 6269** when a new virtual table is be being created or reinitialized. 6270** 6271** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6272** is a pointer to a destructor for the pClientData. ^SQLite will 6273** invoke the destructor function (if it is not NULL) when SQLite 6274** no longer needs the pClientData pointer. ^The destructor will also 6275** be invoked if the call to sqlite3_create_module_v2() fails. 6276** ^The sqlite3_create_module() 6277** interface is equivalent to sqlite3_create_module_v2() with a NULL 6278** destructor. 6279*/ 6280int sqlite3_create_module( 6281 sqlite3 *db, /* SQLite connection to register module with */ 6282 const char *zName, /* Name of the module */ 6283 const sqlite3_module *p, /* Methods for the module */ 6284 void *pClientData /* Client data for xCreate/xConnect */ 6285); 6286int sqlite3_create_module_v2( 6287 sqlite3 *db, /* SQLite connection to register module with */ 6288 const char *zName, /* Name of the module */ 6289 const sqlite3_module *p, /* Methods for the module */ 6290 void *pClientData, /* Client data for xCreate/xConnect */ 6291 void(*xDestroy)(void*) /* Module destructor function */ 6292); 6293 6294/* 6295** CAPI3REF: Virtual Table Instance Object 6296** KEYWORDS: sqlite3_vtab 6297** 6298** Every [virtual table module] implementation uses a subclass 6299** of this object to describe a particular instance 6300** of the [virtual table]. Each subclass will 6301** be tailored to the specific needs of the module implementation. 6302** The purpose of this superclass is to define certain fields that are 6303** common to all module implementations. 6304** 6305** ^Virtual tables methods can set an error message by assigning a 6306** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6307** take care that any prior string is freed by a call to [sqlite3_free()] 6308** prior to assigning a new string to zErrMsg. ^After the error message 6309** is delivered up to the client application, the string will be automatically 6310** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6311*/ 6312struct sqlite3_vtab { 6313 const sqlite3_module *pModule; /* The module for this virtual table */ 6314 int nRef; /* Number of open cursors */ 6315 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6316 /* Virtual table implementations will typically add additional fields */ 6317}; 6318 6319/* 6320** CAPI3REF: Virtual Table Cursor Object 6321** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6322** 6323** Every [virtual table module] implementation uses a subclass of the 6324** following structure to describe cursors that point into the 6325** [virtual table] and are used 6326** to loop through the virtual table. Cursors are created using the 6327** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6328** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6329** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6330** of the module. Each module implementation will define 6331** the content of a cursor structure to suit its own needs. 6332** 6333** This superclass exists in order to define fields of the cursor that 6334** are common to all implementations. 6335*/ 6336struct sqlite3_vtab_cursor { 6337 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6338 /* Virtual table implementations will typically add additional fields */ 6339}; 6340 6341/* 6342** CAPI3REF: Declare The Schema Of A Virtual Table 6343** 6344** ^The [xCreate] and [xConnect] methods of a 6345** [virtual table module] call this interface 6346** to declare the format (the names and datatypes of the columns) of 6347** the virtual tables they implement. 6348*/ 6349int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6350 6351/* 6352** CAPI3REF: Overload A Function For A Virtual Table 6353** METHOD: sqlite3 6354** 6355** ^(Virtual tables can provide alternative implementations of functions 6356** using the [xFindFunction] method of the [virtual table module]. 6357** But global versions of those functions 6358** must exist in order to be overloaded.)^ 6359** 6360** ^(This API makes sure a global version of a function with a particular 6361** name and number of parameters exists. If no such function exists 6362** before this API is called, a new function is created.)^ ^The implementation 6363** of the new function always causes an exception to be thrown. So 6364** the new function is not good for anything by itself. Its only 6365** purpose is to be a placeholder function that can be overloaded 6366** by a [virtual table]. 6367*/ 6368int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6369 6370/* 6371** The interface to the virtual-table mechanism defined above (back up 6372** to a comment remarkably similar to this one) is currently considered 6373** to be experimental. The interface might change in incompatible ways. 6374** If this is a problem for you, do not use the interface at this time. 6375** 6376** When the virtual-table mechanism stabilizes, we will declare the 6377** interface fixed, support it indefinitely, and remove this comment. 6378*/ 6379 6380/* 6381** CAPI3REF: A Handle To An Open BLOB 6382** KEYWORDS: {BLOB handle} {BLOB handles} 6383** 6384** An instance of this object represents an open BLOB on which 6385** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6386** ^Objects of this type are created by [sqlite3_blob_open()] 6387** and destroyed by [sqlite3_blob_close()]. 6388** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6389** can be used to read or write small subsections of the BLOB. 6390** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6391*/ 6392typedef struct sqlite3_blob sqlite3_blob; 6393 6394/* 6395** CAPI3REF: Open A BLOB For Incremental I/O 6396** METHOD: sqlite3 6397** CONSTRUCTOR: sqlite3_blob 6398** 6399** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6400** in row iRow, column zColumn, table zTable in database zDb; 6401** in other words, the same BLOB that would be selected by: 6402** 6403** <pre> 6404** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6405** </pre>)^ 6406** 6407** ^(Parameter zDb is not the filename that contains the database, but 6408** rather the symbolic name of the database. For attached databases, this is 6409** the name that appears after the AS keyword in the [ATTACH] statement. 6410** For the main database file, the database name is "main". For TEMP 6411** tables, the database name is "temp".)^ 6412** 6413** ^If the flags parameter is non-zero, then the BLOB is opened for read 6414** and write access. ^If the flags parameter is zero, the BLOB is opened for 6415** read-only access. 6416** 6417** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6418** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6419** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6420** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6421** on *ppBlob after this function it returns. 6422** 6423** This function fails with SQLITE_ERROR if any of the following are true: 6424** <ul> 6425** <li> ^(Database zDb does not exist)^, 6426** <li> ^(Table zTable does not exist within database zDb)^, 6427** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6428** <li> ^(Column zColumn does not exist)^, 6429** <li> ^(Row iRow is not present in the table)^, 6430** <li> ^(The specified column of row iRow contains a value that is not 6431** a TEXT or BLOB value)^, 6432** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6433** constraint and the blob is being opened for read/write access)^, 6434** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6435** column zColumn is part of a [child key] definition and the blob is 6436** being opened for read/write access)^. 6437** </ul> 6438** 6439** ^Unless it returns SQLITE_MISUSE, this function sets the 6440** [database connection] error code and message accessible via 6441** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6442** 6443** A BLOB referenced by sqlite3_blob_open() may be read using the 6444** [sqlite3_blob_read()] interface and modified by using 6445** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6446** different row of the same table using the [sqlite3_blob_reopen()] 6447** interface. However, the column, table, or database of a [BLOB handle] 6448** cannot be changed after the [BLOB handle] is opened. 6449** 6450** ^(If the row that a BLOB handle points to is modified by an 6451** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6452** then the BLOB handle is marked as "expired". 6453** This is true if any column of the row is changed, even a column 6454** other than the one the BLOB handle is open on.)^ 6455** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6456** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6457** ^(Changes written into a BLOB prior to the BLOB expiring are not 6458** rolled back by the expiration of the BLOB. Such changes will eventually 6459** commit if the transaction continues to completion.)^ 6460** 6461** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6462** the opened blob. ^The size of a blob may not be changed by this 6463** interface. Use the [UPDATE] SQL command to change the size of a 6464** blob. 6465** 6466** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6467** and the built-in [zeroblob] SQL function may be used to create a 6468** zero-filled blob to read or write using the incremental-blob interface. 6469** 6470** To avoid a resource leak, every open [BLOB handle] should eventually 6471** be released by a call to [sqlite3_blob_close()]. 6472** 6473** See also: [sqlite3_blob_close()], 6474** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6475** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6476*/ 6477int sqlite3_blob_open( 6478 sqlite3*, 6479 const char *zDb, 6480 const char *zTable, 6481 const char *zColumn, 6482 sqlite3_int64 iRow, 6483 int flags, 6484 sqlite3_blob **ppBlob 6485); 6486 6487/* 6488** CAPI3REF: Move a BLOB Handle to a New Row 6489** METHOD: sqlite3_blob 6490** 6491** ^This function is used to move an existing [BLOB handle] so that it points 6492** to a different row of the same database table. ^The new row is identified 6493** by the rowid value passed as the second argument. Only the row can be 6494** changed. ^The database, table and column on which the blob handle is open 6495** remain the same. Moving an existing [BLOB handle] to a new row is 6496** faster than closing the existing handle and opening a new one. 6497** 6498** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6499** it must exist and there must be either a blob or text value stored in 6500** the nominated column.)^ ^If the new row is not present in the table, or if 6501** it does not contain a blob or text value, or if another error occurs, an 6502** SQLite error code is returned and the blob handle is considered aborted. 6503** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6504** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6505** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6506** always returns zero. 6507** 6508** ^This function sets the database handle error code and message. 6509*/ 6510int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6511 6512/* 6513** CAPI3REF: Close A BLOB Handle 6514** DESTRUCTOR: sqlite3_blob 6515** 6516** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6517** unconditionally. Even if this routine returns an error code, the 6518** handle is still closed.)^ 6519** 6520** ^If the blob handle being closed was opened for read-write access, and if 6521** the database is in auto-commit mode and there are no other open read-write 6522** blob handles or active write statements, the current transaction is 6523** committed. ^If an error occurs while committing the transaction, an error 6524** code is returned and the transaction rolled back. 6525** 6526** Calling this function with an argument that is not a NULL pointer or an 6527** open blob handle results in undefined behaviour. ^Calling this routine 6528** with a null pointer (such as would be returned by a failed call to 6529** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6530** is passed a valid open blob handle, the values returned by the 6531** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6532*/ 6533int sqlite3_blob_close(sqlite3_blob *); 6534 6535/* 6536** CAPI3REF: Return The Size Of An Open BLOB 6537** METHOD: sqlite3_blob 6538** 6539** ^Returns the size in bytes of the BLOB accessible via the 6540** successfully opened [BLOB handle] in its only argument. ^The 6541** incremental blob I/O routines can only read or overwriting existing 6542** blob content; they cannot change the size of a blob. 6543** 6544** This routine only works on a [BLOB handle] which has been created 6545** by a prior successful call to [sqlite3_blob_open()] and which has not 6546** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6547** to this routine results in undefined and probably undesirable behavior. 6548*/ 6549int sqlite3_blob_bytes(sqlite3_blob *); 6550 6551/* 6552** CAPI3REF: Read Data From A BLOB Incrementally 6553** METHOD: sqlite3_blob 6554** 6555** ^(This function is used to read data from an open [BLOB handle] into a 6556** caller-supplied buffer. N bytes of data are copied into buffer Z 6557** from the open BLOB, starting at offset iOffset.)^ 6558** 6559** ^If offset iOffset is less than N bytes from the end of the BLOB, 6560** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6561** less than zero, [SQLITE_ERROR] is returned and no data is read. 6562** ^The size of the blob (and hence the maximum value of N+iOffset) 6563** can be determined using the [sqlite3_blob_bytes()] interface. 6564** 6565** ^An attempt to read from an expired [BLOB handle] fails with an 6566** error code of [SQLITE_ABORT]. 6567** 6568** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6569** Otherwise, an [error code] or an [extended error code] is returned.)^ 6570** 6571** This routine only works on a [BLOB handle] which has been created 6572** by a prior successful call to [sqlite3_blob_open()] and which has not 6573** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6574** to this routine results in undefined and probably undesirable behavior. 6575** 6576** See also: [sqlite3_blob_write()]. 6577*/ 6578int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6579 6580/* 6581** CAPI3REF: Write Data Into A BLOB Incrementally 6582** METHOD: sqlite3_blob 6583** 6584** ^(This function is used to write data into an open [BLOB handle] from a 6585** caller-supplied buffer. N bytes of data are copied from the buffer Z 6586** into the open BLOB, starting at offset iOffset.)^ 6587** 6588** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6589** Otherwise, an [error code] or an [extended error code] is returned.)^ 6590** ^Unless SQLITE_MISUSE is returned, this function sets the 6591** [database connection] error code and message accessible via 6592** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6593** 6594** ^If the [BLOB handle] passed as the first argument was not opened for 6595** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6596** this function returns [SQLITE_READONLY]. 6597** 6598** This function may only modify the contents of the BLOB; it is 6599** not possible to increase the size of a BLOB using this API. 6600** ^If offset iOffset is less than N bytes from the end of the BLOB, 6601** [SQLITE_ERROR] is returned and no data is written. The size of the 6602** BLOB (and hence the maximum value of N+iOffset) can be determined 6603** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6604** than zero [SQLITE_ERROR] is returned and no data is written. 6605** 6606** ^An attempt to write to an expired [BLOB handle] fails with an 6607** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6608** before the [BLOB handle] expired are not rolled back by the 6609** expiration of the handle, though of course those changes might 6610** have been overwritten by the statement that expired the BLOB handle 6611** or by other independent statements. 6612** 6613** This routine only works on a [BLOB handle] which has been created 6614** by a prior successful call to [sqlite3_blob_open()] and which has not 6615** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6616** to this routine results in undefined and probably undesirable behavior. 6617** 6618** See also: [sqlite3_blob_read()]. 6619*/ 6620int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6621 6622/* 6623** CAPI3REF: Virtual File System Objects 6624** 6625** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6626** that SQLite uses to interact 6627** with the underlying operating system. Most SQLite builds come with a 6628** single default VFS that is appropriate for the host computer. 6629** New VFSes can be registered and existing VFSes can be unregistered. 6630** The following interfaces are provided. 6631** 6632** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6633** ^Names are case sensitive. 6634** ^Names are zero-terminated UTF-8 strings. 6635** ^If there is no match, a NULL pointer is returned. 6636** ^If zVfsName is NULL then the default VFS is returned. 6637** 6638** ^New VFSes are registered with sqlite3_vfs_register(). 6639** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6640** ^The same VFS can be registered multiple times without injury. 6641** ^To make an existing VFS into the default VFS, register it again 6642** with the makeDflt flag set. If two different VFSes with the 6643** same name are registered, the behavior is undefined. If a 6644** VFS is registered with a name that is NULL or an empty string, 6645** then the behavior is undefined. 6646** 6647** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6648** ^(If the default VFS is unregistered, another VFS is chosen as 6649** the default. The choice for the new VFS is arbitrary.)^ 6650*/ 6651sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6652int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6653int sqlite3_vfs_unregister(sqlite3_vfs*); 6654 6655/* 6656** CAPI3REF: Mutexes 6657** 6658** The SQLite core uses these routines for thread 6659** synchronization. Though they are intended for internal 6660** use by SQLite, code that links against SQLite is 6661** permitted to use any of these routines. 6662** 6663** The SQLite source code contains multiple implementations 6664** of these mutex routines. An appropriate implementation 6665** is selected automatically at compile-time. The following 6666** implementations are available in the SQLite core: 6667** 6668** <ul> 6669** <li> SQLITE_MUTEX_PTHREADS 6670** <li> SQLITE_MUTEX_W32 6671** <li> SQLITE_MUTEX_NOOP 6672** </ul> 6673** 6674** The SQLITE_MUTEX_NOOP implementation is a set of routines 6675** that does no real locking and is appropriate for use in 6676** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6677** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6678** and Windows. 6679** 6680** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6681** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6682** implementation is included with the library. In this case the 6683** application must supply a custom mutex implementation using the 6684** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6685** before calling sqlite3_initialize() or any other public sqlite3_ 6686** function that calls sqlite3_initialize(). 6687** 6688** ^The sqlite3_mutex_alloc() routine allocates a new 6689** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6690** routine returns NULL if it is unable to allocate the requested 6691** mutex. The argument to sqlite3_mutex_alloc() must one of these 6692** integer constants: 6693** 6694** <ul> 6695** <li> SQLITE_MUTEX_FAST 6696** <li> SQLITE_MUTEX_RECURSIVE 6697** <li> SQLITE_MUTEX_STATIC_MASTER 6698** <li> SQLITE_MUTEX_STATIC_MEM 6699** <li> SQLITE_MUTEX_STATIC_OPEN 6700** <li> SQLITE_MUTEX_STATIC_PRNG 6701** <li> SQLITE_MUTEX_STATIC_LRU 6702** <li> SQLITE_MUTEX_STATIC_PMEM 6703** <li> SQLITE_MUTEX_STATIC_APP1 6704** <li> SQLITE_MUTEX_STATIC_APP2 6705** <li> SQLITE_MUTEX_STATIC_APP3 6706** <li> SQLITE_MUTEX_STATIC_VFS1 6707** <li> SQLITE_MUTEX_STATIC_VFS2 6708** <li> SQLITE_MUTEX_STATIC_VFS3 6709** </ul> 6710** 6711** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6712** cause sqlite3_mutex_alloc() to create 6713** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6714** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6715** The mutex implementation does not need to make a distinction 6716** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6717** not want to. SQLite will only request a recursive mutex in 6718** cases where it really needs one. If a faster non-recursive mutex 6719** implementation is available on the host platform, the mutex subsystem 6720** might return such a mutex in response to SQLITE_MUTEX_FAST. 6721** 6722** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6723** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6724** a pointer to a static preexisting mutex. ^Nine static mutexes are 6725** used by the current version of SQLite. Future versions of SQLite 6726** may add additional static mutexes. Static mutexes are for internal 6727** use by SQLite only. Applications that use SQLite mutexes should 6728** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 6729** SQLITE_MUTEX_RECURSIVE. 6730** 6731** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 6732** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 6733** returns a different mutex on every call. ^For the static 6734** mutex types, the same mutex is returned on every call that has 6735** the same type number. 6736** 6737** ^The sqlite3_mutex_free() routine deallocates a previously 6738** allocated dynamic mutex. Attempting to deallocate a static 6739** mutex results in undefined behavior. 6740** 6741** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 6742** to enter a mutex. ^If another thread is already within the mutex, 6743** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 6744** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 6745** upon successful entry. ^(Mutexes created using 6746** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 6747** In such cases, the 6748** mutex must be exited an equal number of times before another thread 6749** can enter.)^ If the same thread tries to enter any mutex other 6750** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 6751** 6752** ^(Some systems (for example, Windows 95) do not support the operation 6753** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 6754** will always return SQLITE_BUSY. The SQLite core only ever uses 6755** sqlite3_mutex_try() as an optimization so this is acceptable 6756** behavior.)^ 6757** 6758** ^The sqlite3_mutex_leave() routine exits a mutex that was 6759** previously entered by the same thread. The behavior 6760** is undefined if the mutex is not currently entered by the 6761** calling thread or is not currently allocated. 6762** 6763** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 6764** sqlite3_mutex_leave() is a NULL pointer, then all three routines 6765** behave as no-ops. 6766** 6767** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 6768*/ 6769sqlite3_mutex *sqlite3_mutex_alloc(int); 6770void sqlite3_mutex_free(sqlite3_mutex*); 6771void sqlite3_mutex_enter(sqlite3_mutex*); 6772int sqlite3_mutex_try(sqlite3_mutex*); 6773void sqlite3_mutex_leave(sqlite3_mutex*); 6774 6775/* 6776** CAPI3REF: Mutex Methods Object 6777** 6778** An instance of this structure defines the low-level routines 6779** used to allocate and use mutexes. 6780** 6781** Usually, the default mutex implementations provided by SQLite are 6782** sufficient, however the application has the option of substituting a custom 6783** implementation for specialized deployments or systems for which SQLite 6784** does not provide a suitable implementation. In this case, the application 6785** creates and populates an instance of this structure to pass 6786** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 6787** Additionally, an instance of this structure can be used as an 6788** output variable when querying the system for the current mutex 6789** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 6790** 6791** ^The xMutexInit method defined by this structure is invoked as 6792** part of system initialization by the sqlite3_initialize() function. 6793** ^The xMutexInit routine is called by SQLite exactly once for each 6794** effective call to [sqlite3_initialize()]. 6795** 6796** ^The xMutexEnd method defined by this structure is invoked as 6797** part of system shutdown by the sqlite3_shutdown() function. The 6798** implementation of this method is expected to release all outstanding 6799** resources obtained by the mutex methods implementation, especially 6800** those obtained by the xMutexInit method. ^The xMutexEnd() 6801** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 6802** 6803** ^(The remaining seven methods defined by this structure (xMutexAlloc, 6804** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 6805** xMutexNotheld) implement the following interfaces (respectively): 6806** 6807** <ul> 6808** <li> [sqlite3_mutex_alloc()] </li> 6809** <li> [sqlite3_mutex_free()] </li> 6810** <li> [sqlite3_mutex_enter()] </li> 6811** <li> [sqlite3_mutex_try()] </li> 6812** <li> [sqlite3_mutex_leave()] </li> 6813** <li> [sqlite3_mutex_held()] </li> 6814** <li> [sqlite3_mutex_notheld()] </li> 6815** </ul>)^ 6816** 6817** The only difference is that the public sqlite3_XXX functions enumerated 6818** above silently ignore any invocations that pass a NULL pointer instead 6819** of a valid mutex handle. The implementations of the methods defined 6820** by this structure are not required to handle this case, the results 6821** of passing a NULL pointer instead of a valid mutex handle are undefined 6822** (i.e. it is acceptable to provide an implementation that segfaults if 6823** it is passed a NULL pointer). 6824** 6825** The xMutexInit() method must be threadsafe. It must be harmless to 6826** invoke xMutexInit() multiple times within the same process and without 6827** intervening calls to xMutexEnd(). Second and subsequent calls to 6828** xMutexInit() must be no-ops. 6829** 6830** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 6831** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 6832** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 6833** memory allocation for a fast or recursive mutex. 6834** 6835** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 6836** called, but only if the prior call to xMutexInit returned SQLITE_OK. 6837** If xMutexInit fails in any way, it is expected to clean up after itself 6838** prior to returning. 6839*/ 6840typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 6841struct sqlite3_mutex_methods { 6842 int (*xMutexInit)(void); 6843 int (*xMutexEnd)(void); 6844 sqlite3_mutex *(*xMutexAlloc)(int); 6845 void (*xMutexFree)(sqlite3_mutex *); 6846 void (*xMutexEnter)(sqlite3_mutex *); 6847 int (*xMutexTry)(sqlite3_mutex *); 6848 void (*xMutexLeave)(sqlite3_mutex *); 6849 int (*xMutexHeld)(sqlite3_mutex *); 6850 int (*xMutexNotheld)(sqlite3_mutex *); 6851}; 6852 6853/* 6854** CAPI3REF: Mutex Verification Routines 6855** 6856** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 6857** are intended for use inside assert() statements. The SQLite core 6858** never uses these routines except inside an assert() and applications 6859** are advised to follow the lead of the core. The SQLite core only 6860** provides implementations for these routines when it is compiled 6861** with the SQLITE_DEBUG flag. External mutex implementations 6862** are only required to provide these routines if SQLITE_DEBUG is 6863** defined and if NDEBUG is not defined. 6864** 6865** These routines should return true if the mutex in their argument 6866** is held or not held, respectively, by the calling thread. 6867** 6868** The implementation is not required to provide versions of these 6869** routines that actually work. If the implementation does not provide working 6870** versions of these routines, it should at least provide stubs that always 6871** return true so that one does not get spurious assertion failures. 6872** 6873** If the argument to sqlite3_mutex_held() is a NULL pointer then 6874** the routine should return 1. This seems counter-intuitive since 6875** clearly the mutex cannot be held if it does not exist. But 6876** the reason the mutex does not exist is because the build is not 6877** using mutexes. And we do not want the assert() containing the 6878** call to sqlite3_mutex_held() to fail, so a non-zero return is 6879** the appropriate thing to do. The sqlite3_mutex_notheld() 6880** interface should also return 1 when given a NULL pointer. 6881*/ 6882#ifndef NDEBUG 6883int sqlite3_mutex_held(sqlite3_mutex*); 6884int sqlite3_mutex_notheld(sqlite3_mutex*); 6885#endif 6886 6887/* 6888** CAPI3REF: Mutex Types 6889** 6890** The [sqlite3_mutex_alloc()] interface takes a single argument 6891** which is one of these integer constants. 6892** 6893** The set of static mutexes may change from one SQLite release to the 6894** next. Applications that override the built-in mutex logic must be 6895** prepared to accommodate additional static mutexes. 6896*/ 6897#define SQLITE_MUTEX_FAST 0 6898#define SQLITE_MUTEX_RECURSIVE 1 6899#define SQLITE_MUTEX_STATIC_MASTER 2 6900#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 6901#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 6902#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 6903#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 6904#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 6905#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 6906#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 6907#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 6908#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 6909#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 6910#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 6911#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 6912#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 6913 6914/* 6915** CAPI3REF: Retrieve the mutex for a database connection 6916** METHOD: sqlite3 6917** 6918** ^This interface returns a pointer the [sqlite3_mutex] object that 6919** serializes access to the [database connection] given in the argument 6920** when the [threading mode] is Serialized. 6921** ^If the [threading mode] is Single-thread or Multi-thread then this 6922** routine returns a NULL pointer. 6923*/ 6924sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 6925 6926/* 6927** CAPI3REF: Low-Level Control Of Database Files 6928** METHOD: sqlite3 6929** 6930** ^The [sqlite3_file_control()] interface makes a direct call to the 6931** xFileControl method for the [sqlite3_io_methods] object associated 6932** with a particular database identified by the second argument. ^The 6933** name of the database is "main" for the main database or "temp" for the 6934** TEMP database, or the name that appears after the AS keyword for 6935** databases that are added using the [ATTACH] SQL command. 6936** ^A NULL pointer can be used in place of "main" to refer to the 6937** main database file. 6938** ^The third and fourth parameters to this routine 6939** are passed directly through to the second and third parameters of 6940** the xFileControl method. ^The return value of the xFileControl 6941** method becomes the return value of this routine. 6942** 6943** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 6944** a pointer to the underlying [sqlite3_file] object to be written into 6945** the space pointed to by the 4th parameter. ^The [SQLITE_FCNTL_FILE_POINTER] 6946** case is a short-circuit path which does not actually invoke the 6947** underlying sqlite3_io_methods.xFileControl method. 6948** 6949** ^If the second parameter (zDbName) does not match the name of any 6950** open database file, then SQLITE_ERROR is returned. ^This error 6951** code is not remembered and will not be recalled by [sqlite3_errcode()] 6952** or [sqlite3_errmsg()]. The underlying xFileControl method might 6953** also return SQLITE_ERROR. There is no way to distinguish between 6954** an incorrect zDbName and an SQLITE_ERROR return from the underlying 6955** xFileControl method. 6956** 6957** See also: [file control opcodes] 6958*/ 6959int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 6960 6961/* 6962** CAPI3REF: Testing Interface 6963** 6964** ^The sqlite3_test_control() interface is used to read out internal 6965** state of SQLite and to inject faults into SQLite for testing 6966** purposes. ^The first parameter is an operation code that determines 6967** the number, meaning, and operation of all subsequent parameters. 6968** 6969** This interface is not for use by applications. It exists solely 6970** for verifying the correct operation of the SQLite library. Depending 6971** on how the SQLite library is compiled, this interface might not exist. 6972** 6973** The details of the operation codes, their meanings, the parameters 6974** they take, and what they do are all subject to change without notice. 6975** Unlike most of the SQLite API, this function is not guaranteed to 6976** operate consistently from one release to the next. 6977*/ 6978int sqlite3_test_control(int op, ...); 6979 6980/* 6981** CAPI3REF: Testing Interface Operation Codes 6982** 6983** These constants are the valid operation code parameters used 6984** as the first argument to [sqlite3_test_control()]. 6985** 6986** These parameters and their meanings are subject to change 6987** without notice. These values are for testing purposes only. 6988** Applications should not use any of these parameters or the 6989** [sqlite3_test_control()] interface. 6990*/ 6991#define SQLITE_TESTCTRL_FIRST 5 6992#define SQLITE_TESTCTRL_PRNG_SAVE 5 6993#define SQLITE_TESTCTRL_PRNG_RESTORE 6 6994#define SQLITE_TESTCTRL_PRNG_RESET 7 6995#define SQLITE_TESTCTRL_BITVEC_TEST 8 6996#define SQLITE_TESTCTRL_FAULT_INSTALL 9 6997#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 6998#define SQLITE_TESTCTRL_PENDING_BYTE 11 6999#define SQLITE_TESTCTRL_ASSERT 12 7000#define SQLITE_TESTCTRL_ALWAYS 13 7001#define SQLITE_TESTCTRL_RESERVE 14 7002#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7003#define SQLITE_TESTCTRL_ISKEYWORD 16 7004#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7005#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7006#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7007#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7008#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7009#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7010#define SQLITE_TESTCTRL_BYTEORDER 22 7011#define SQLITE_TESTCTRL_ISINIT 23 7012#define SQLITE_TESTCTRL_SORTER_MMAP 24 7013#define SQLITE_TESTCTRL_IMPOSTER 25 7014#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7015#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */ 7016 7017/* 7018** CAPI3REF: SQLite Runtime Status 7019** 7020** ^These interfaces are used to retrieve runtime status information 7021** about the performance of SQLite, and optionally to reset various 7022** highwater marks. ^The first argument is an integer code for 7023** the specific parameter to measure. ^(Recognized integer codes 7024** are of the form [status parameters | SQLITE_STATUS_...].)^ 7025** ^The current value of the parameter is returned into *pCurrent. 7026** ^The highest recorded value is returned in *pHighwater. ^If the 7027** resetFlag is true, then the highest record value is reset after 7028** *pHighwater is written. ^(Some parameters do not record the highest 7029** value. For those parameters 7030** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7031** ^(Other parameters record only the highwater mark and not the current 7032** value. For these latter parameters nothing is written into *pCurrent.)^ 7033** 7034** ^The sqlite3_status() and sqlite3_status64() routines return 7035** SQLITE_OK on success and a non-zero [error code] on failure. 7036** 7037** If either the current value or the highwater mark is too large to 7038** be represented by a 32-bit integer, then the values returned by 7039** sqlite3_status() are undefined. 7040** 7041** See also: [sqlite3_db_status()] 7042*/ 7043int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7044int sqlite3_status64( 7045 int op, 7046 sqlite3_int64 *pCurrent, 7047 sqlite3_int64 *pHighwater, 7048 int resetFlag 7049); 7050 7051 7052/* 7053** CAPI3REF: Status Parameters 7054** KEYWORDS: {status parameters} 7055** 7056** These integer constants designate various run-time status parameters 7057** that can be returned by [sqlite3_status()]. 7058** 7059** <dl> 7060** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7061** <dd>This parameter is the current amount of memory checked out 7062** using [sqlite3_malloc()], either directly or indirectly. The 7063** figure includes calls made to [sqlite3_malloc()] by the application 7064** and internal memory usage by the SQLite library. Auxiliary page-cache 7065** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7066** this parameter. The amount returned is the sum of the allocation 7067** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7068** 7069** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7070** <dd>This parameter records the largest memory allocation request 7071** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7072** internal equivalents). Only the value returned in the 7073** *pHighwater parameter to [sqlite3_status()] is of interest. 7074** The value written into the *pCurrent parameter is undefined.</dd>)^ 7075** 7076** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7077** <dd>This parameter records the number of separate memory allocations 7078** currently checked out.</dd>)^ 7079** 7080** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7081** <dd>This parameter returns the number of pages used out of the 7082** [pagecache memory allocator] that was configured using 7083** [SQLITE_CONFIG_PAGECACHE]. The 7084** value returned is in pages, not in bytes.</dd>)^ 7085** 7086** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7087** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7088** <dd>This parameter returns the number of bytes of page cache 7089** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7090** buffer and where forced to overflow to [sqlite3_malloc()]. The 7091** returned value includes allocations that overflowed because they 7092** where too large (they were larger than the "sz" parameter to 7093** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7094** no space was left in the page cache.</dd>)^ 7095** 7096** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7097** <dd>This parameter records the largest memory allocation request 7098** handed to [pagecache memory allocator]. Only the value returned in the 7099** *pHighwater parameter to [sqlite3_status()] is of interest. 7100** The value written into the *pCurrent parameter is undefined.</dd>)^ 7101** 7102** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7103** <dd>No longer used.</dd> 7104** 7105** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7106** <dd>No longer used.</dd> 7107** 7108** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7109** <dd>No longer used.</dd> 7110** 7111** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7112** <dd>The *pHighwater parameter records the deepest parser stack. 7113** The *pCurrent value is undefined. The *pHighwater value is only 7114** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7115** </dl> 7116** 7117** New status parameters may be added from time to time. 7118*/ 7119#define SQLITE_STATUS_MEMORY_USED 0 7120#define SQLITE_STATUS_PAGECACHE_USED 1 7121#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7122#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7123#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7124#define SQLITE_STATUS_MALLOC_SIZE 5 7125#define SQLITE_STATUS_PARSER_STACK 6 7126#define SQLITE_STATUS_PAGECACHE_SIZE 7 7127#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7128#define SQLITE_STATUS_MALLOC_COUNT 9 7129 7130/* 7131** CAPI3REF: Database Connection Status 7132** METHOD: sqlite3 7133** 7134** ^This interface is used to retrieve runtime status information 7135** about a single [database connection]. ^The first argument is the 7136** database connection object to be interrogated. ^The second argument 7137** is an integer constant, taken from the set of 7138** [SQLITE_DBSTATUS options], that 7139** determines the parameter to interrogate. The set of 7140** [SQLITE_DBSTATUS options] is likely 7141** to grow in future releases of SQLite. 7142** 7143** ^The current value of the requested parameter is written into *pCur 7144** and the highest instantaneous value is written into *pHiwtr. ^If 7145** the resetFlg is true, then the highest instantaneous value is 7146** reset back down to the current value. 7147** 7148** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7149** non-zero [error code] on failure. 7150** 7151** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7152*/ 7153int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7154 7155/* 7156** CAPI3REF: Status Parameters for database connections 7157** KEYWORDS: {SQLITE_DBSTATUS options} 7158** 7159** These constants are the available integer "verbs" that can be passed as 7160** the second argument to the [sqlite3_db_status()] interface. 7161** 7162** New verbs may be added in future releases of SQLite. Existing verbs 7163** might be discontinued. Applications should check the return code from 7164** [sqlite3_db_status()] to make sure that the call worked. 7165** The [sqlite3_db_status()] interface will return a non-zero error code 7166** if a discontinued or unsupported verb is invoked. 7167** 7168** <dl> 7169** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7170** <dd>This parameter returns the number of lookaside memory slots currently 7171** checked out.</dd>)^ 7172** 7173** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7174** <dd>This parameter returns the number malloc attempts that were 7175** satisfied using lookaside memory. Only the high-water value is meaningful; 7176** the current value is always zero.)^ 7177** 7178** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7179** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7180** <dd>This parameter returns the number malloc attempts that might have 7181** been satisfied using lookaside memory but failed due to the amount of 7182** memory requested being larger than the lookaside slot size. 7183** Only the high-water value is meaningful; 7184** the current value is always zero.)^ 7185** 7186** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7187** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7188** <dd>This parameter returns the number malloc attempts that might have 7189** been satisfied using lookaside memory but failed due to all lookaside 7190** memory already being in use. 7191** Only the high-water value is meaningful; 7192** the current value is always zero.)^ 7193** 7194** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7195** <dd>This parameter returns the approximate number of bytes of heap 7196** memory used by all pager caches associated with the database connection.)^ 7197** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7198** 7199** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7200** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7201** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7202** pager cache is shared between two or more connections the bytes of heap 7203** memory used by that pager cache is divided evenly between the attached 7204** connections.)^ In other words, if none of the pager caches associated 7205** with the database connection are shared, this request returns the same 7206** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7207** shared, the value returned by this call will be smaller than that returned 7208** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7209** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7210** 7211** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7212** <dd>This parameter returns the approximate number of bytes of heap 7213** memory used to store the schema for all databases associated 7214** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7215** ^The full amount of memory used by the schemas is reported, even if the 7216** schema memory is shared with other database connections due to 7217** [shared cache mode] being enabled. 7218** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7219** 7220** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7221** <dd>This parameter returns the approximate number of bytes of heap 7222** and lookaside memory used by all prepared statements associated with 7223** the database connection.)^ 7224** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7225** </dd> 7226** 7227** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7228** <dd>This parameter returns the number of pager cache hits that have 7229** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7230** is always 0. 7231** </dd> 7232** 7233** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7234** <dd>This parameter returns the number of pager cache misses that have 7235** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7236** is always 0. 7237** </dd> 7238** 7239** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7240** <dd>This parameter returns the number of dirty cache entries that have 7241** been written to disk. Specifically, the number of pages written to the 7242** wal file in wal mode databases, or the number of pages written to the 7243** database file in rollback mode databases. Any pages written as part of 7244** transaction rollback or database recovery operations are not included. 7245** If an IO or other error occurs while writing a page to disk, the effect 7246** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7247** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7248** </dd> 7249** 7250** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 7251** <dd>This parameter returns the number of dirty cache entries that have 7252** been written to disk in the middle of a transaction due to the page 7253** cache overflowing. Transactions are more efficient if they are written 7254** to disk all at once. When pages spill mid-transaction, that introduces 7255** additional overhead. This parameter can be used help identify 7256** inefficiencies that can be resolve by increasing the cache size. 7257** </dd> 7258** 7259** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7260** <dd>This parameter returns zero for the current value if and only if 7261** all foreign key constraints (deferred or immediate) have been 7262** resolved.)^ ^The highwater mark is always 0. 7263** </dd> 7264** </dl> 7265*/ 7266#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7267#define SQLITE_DBSTATUS_CACHE_USED 1 7268#define SQLITE_DBSTATUS_SCHEMA_USED 2 7269#define SQLITE_DBSTATUS_STMT_USED 3 7270#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7271#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7272#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7273#define SQLITE_DBSTATUS_CACHE_HIT 7 7274#define SQLITE_DBSTATUS_CACHE_MISS 8 7275#define SQLITE_DBSTATUS_CACHE_WRITE 9 7276#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7277#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7278#define SQLITE_DBSTATUS_CACHE_SPILL 12 7279#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 7280 7281 7282/* 7283** CAPI3REF: Prepared Statement Status 7284** METHOD: sqlite3_stmt 7285** 7286** ^(Each prepared statement maintains various 7287** [SQLITE_STMTSTATUS counters] that measure the number 7288** of times it has performed specific operations.)^ These counters can 7289** be used to monitor the performance characteristics of the prepared 7290** statements. For example, if the number of table steps greatly exceeds 7291** the number of table searches or result rows, that would tend to indicate 7292** that the prepared statement is using a full table scan rather than 7293** an index. 7294** 7295** ^(This interface is used to retrieve and reset counter values from 7296** a [prepared statement]. The first argument is the prepared statement 7297** object to be interrogated. The second argument 7298** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7299** to be interrogated.)^ 7300** ^The current value of the requested counter is returned. 7301** ^If the resetFlg is true, then the counter is reset to zero after this 7302** interface call returns. 7303** 7304** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7305*/ 7306int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7307 7308/* 7309** CAPI3REF: Status Parameters for prepared statements 7310** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7311** 7312** These preprocessor macros define integer codes that name counter 7313** values associated with the [sqlite3_stmt_status()] interface. 7314** The meanings of the various counters are as follows: 7315** 7316** <dl> 7317** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7318** <dd>^This is the number of times that SQLite has stepped forward in 7319** a table as part of a full table scan. Large numbers for this counter 7320** may indicate opportunities for performance improvement through 7321** careful use of indices.</dd> 7322** 7323** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7324** <dd>^This is the number of sort operations that have occurred. 7325** A non-zero value in this counter may indicate an opportunity to 7326** improvement performance through careful use of indices.</dd> 7327** 7328** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7329** <dd>^This is the number of rows inserted into transient indices that 7330** were created automatically in order to help joins run faster. 7331** A non-zero value in this counter may indicate an opportunity to 7332** improvement performance by adding permanent indices that do not 7333** need to be reinitialized each time the statement is run.</dd> 7334** 7335** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7336** <dd>^This is the number of virtual machine operations executed 7337** by the prepared statement if that number is less than or equal 7338** to 2147483647. The number of virtual machine operations can be 7339** used as a proxy for the total work done by the prepared statement. 7340** If the number of virtual machine operations exceeds 2147483647 7341** then the value returned by this statement status code is undefined. 7342** 7343** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7344** <dd>^This is the number of times that the prepare statement has been 7345** automatically regenerated due to schema changes or change to 7346** [bound parameters] that might affect the query plan. 7347** 7348** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7349** <dd>^This is the number of times that the prepared statement has 7350** been run. A single "run" for the purposes of this counter is one 7351** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7352** The counter is incremented on the first [sqlite3_step()] call of each 7353** cycle. 7354** 7355** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7356** <dd>^This is the approximate number of bytes of heap memory 7357** used to store the prepared statement. ^This value is not actually 7358** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7359** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7360** </dd> 7361** </dl> 7362*/ 7363#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7364#define SQLITE_STMTSTATUS_SORT 2 7365#define SQLITE_STMTSTATUS_AUTOINDEX 3 7366#define SQLITE_STMTSTATUS_VM_STEP 4 7367#define SQLITE_STMTSTATUS_REPREPARE 5 7368#define SQLITE_STMTSTATUS_RUN 6 7369#define SQLITE_STMTSTATUS_MEMUSED 99 7370 7371/* 7372** CAPI3REF: Custom Page Cache Object 7373** 7374** The sqlite3_pcache type is opaque. It is implemented by 7375** the pluggable module. The SQLite core has no knowledge of 7376** its size or internal structure and never deals with the 7377** sqlite3_pcache object except by holding and passing pointers 7378** to the object. 7379** 7380** See [sqlite3_pcache_methods2] for additional information. 7381*/ 7382typedef struct sqlite3_pcache sqlite3_pcache; 7383 7384/* 7385** CAPI3REF: Custom Page Cache Object 7386** 7387** The sqlite3_pcache_page object represents a single page in the 7388** page cache. The page cache will allocate instances of this 7389** object. Various methods of the page cache use pointers to instances 7390** of this object as parameters or as their return value. 7391** 7392** See [sqlite3_pcache_methods2] for additional information. 7393*/ 7394typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7395struct sqlite3_pcache_page { 7396 void *pBuf; /* The content of the page */ 7397 void *pExtra; /* Extra information associated with the page */ 7398}; 7399 7400/* 7401** CAPI3REF: Application Defined Page Cache. 7402** KEYWORDS: {page cache} 7403** 7404** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7405** register an alternative page cache implementation by passing in an 7406** instance of the sqlite3_pcache_methods2 structure.)^ 7407** In many applications, most of the heap memory allocated by 7408** SQLite is used for the page cache. 7409** By implementing a 7410** custom page cache using this API, an application can better control 7411** the amount of memory consumed by SQLite, the way in which 7412** that memory is allocated and released, and the policies used to 7413** determine exactly which parts of a database file are cached and for 7414** how long. 7415** 7416** The alternative page cache mechanism is an 7417** extreme measure that is only needed by the most demanding applications. 7418** The built-in page cache is recommended for most uses. 7419** 7420** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7421** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7422** the application may discard the parameter after the call to 7423** [sqlite3_config()] returns.)^ 7424** 7425** [[the xInit() page cache method]] 7426** ^(The xInit() method is called once for each effective 7427** call to [sqlite3_initialize()])^ 7428** (usually only once during the lifetime of the process). ^(The xInit() 7429** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7430** The intent of the xInit() method is to set up global data structures 7431** required by the custom page cache implementation. 7432** ^(If the xInit() method is NULL, then the 7433** built-in default page cache is used instead of the application defined 7434** page cache.)^ 7435** 7436** [[the xShutdown() page cache method]] 7437** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7438** It can be used to clean up 7439** any outstanding resources before process shutdown, if required. 7440** ^The xShutdown() method may be NULL. 7441** 7442** ^SQLite automatically serializes calls to the xInit method, 7443** so the xInit method need not be threadsafe. ^The 7444** xShutdown method is only called from [sqlite3_shutdown()] so it does 7445** not need to be threadsafe either. All other methods must be threadsafe 7446** in multithreaded applications. 7447** 7448** ^SQLite will never invoke xInit() more than once without an intervening 7449** call to xShutdown(). 7450** 7451** [[the xCreate() page cache methods]] 7452** ^SQLite invokes the xCreate() method to construct a new cache instance. 7453** SQLite will typically create one cache instance for each open database file, 7454** though this is not guaranteed. ^The 7455** first parameter, szPage, is the size in bytes of the pages that must 7456** be allocated by the cache. ^szPage will always a power of two. ^The 7457** second parameter szExtra is a number of bytes of extra storage 7458** associated with each page cache entry. ^The szExtra parameter will 7459** a number less than 250. SQLite will use the 7460** extra szExtra bytes on each page to store metadata about the underlying 7461** database page on disk. The value passed into szExtra depends 7462** on the SQLite version, the target platform, and how SQLite was compiled. 7463** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7464** created will be used to cache database pages of a file stored on disk, or 7465** false if it is used for an in-memory database. The cache implementation 7466** does not have to do anything special based with the value of bPurgeable; 7467** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7468** never invoke xUnpin() except to deliberately delete a page. 7469** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7470** false will always have the "discard" flag set to true. 7471** ^Hence, a cache created with bPurgeable false will 7472** never contain any unpinned pages. 7473** 7474** [[the xCachesize() page cache method]] 7475** ^(The xCachesize() method may be called at any time by SQLite to set the 7476** suggested maximum cache-size (number of pages stored by) the cache 7477** instance passed as the first argument. This is the value configured using 7478** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7479** parameter, the implementation is not required to do anything with this 7480** value; it is advisory only. 7481** 7482** [[the xPagecount() page cache methods]] 7483** The xPagecount() method must return the number of pages currently 7484** stored in the cache, both pinned and unpinned. 7485** 7486** [[the xFetch() page cache methods]] 7487** The xFetch() method locates a page in the cache and returns a pointer to 7488** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7489** The pBuf element of the returned sqlite3_pcache_page object will be a 7490** pointer to a buffer of szPage bytes used to store the content of a 7491** single database page. The pExtra element of sqlite3_pcache_page will be 7492** a pointer to the szExtra bytes of extra storage that SQLite has requested 7493** for each entry in the page cache. 7494** 7495** The page to be fetched is determined by the key. ^The minimum key value 7496** is 1. After it has been retrieved using xFetch, the page is considered 7497** to be "pinned". 7498** 7499** If the requested page is already in the page cache, then the page cache 7500** implementation must return a pointer to the page buffer with its content 7501** intact. If the requested page is not already in the cache, then the 7502** cache implementation should use the value of the createFlag 7503** parameter to help it determined what action to take: 7504** 7505** <table border=1 width=85% align=center> 7506** <tr><th> createFlag <th> Behavior when page is not already in cache 7507** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7508** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7509** Otherwise return NULL. 7510** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7511** NULL if allocating a new page is effectively impossible. 7512** </table> 7513** 7514** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7515** will only use a createFlag of 2 after a prior call with a createFlag of 1 7516** failed.)^ In between the to xFetch() calls, SQLite may 7517** attempt to unpin one or more cache pages by spilling the content of 7518** pinned pages to disk and synching the operating system disk cache. 7519** 7520** [[the xUnpin() page cache method]] 7521** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7522** as its second argument. If the third parameter, discard, is non-zero, 7523** then the page must be evicted from the cache. 7524** ^If the discard parameter is 7525** zero, then the page may be discarded or retained at the discretion of 7526** page cache implementation. ^The page cache implementation 7527** may choose to evict unpinned pages at any time. 7528** 7529** The cache must not perform any reference counting. A single 7530** call to xUnpin() unpins the page regardless of the number of prior calls 7531** to xFetch(). 7532** 7533** [[the xRekey() page cache methods]] 7534** The xRekey() method is used to change the key value associated with the 7535** page passed as the second argument. If the cache 7536** previously contains an entry associated with newKey, it must be 7537** discarded. ^Any prior cache entry associated with newKey is guaranteed not 7538** to be pinned. 7539** 7540** When SQLite calls the xTruncate() method, the cache must discard all 7541** existing cache entries with page numbers (keys) greater than or equal 7542** to the value of the iLimit parameter passed to xTruncate(). If any 7543** of these pages are pinned, they are implicitly unpinned, meaning that 7544** they can be safely discarded. 7545** 7546** [[the xDestroy() page cache method]] 7547** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 7548** All resources associated with the specified cache should be freed. ^After 7549** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 7550** handle invalid, and will not use it with any other sqlite3_pcache_methods2 7551** functions. 7552** 7553** [[the xShrink() page cache method]] 7554** ^SQLite invokes the xShrink() method when it wants the page cache to 7555** free up as much of heap memory as possible. The page cache implementation 7556** is not obligated to free any memory, but well-behaved implementations should 7557** do their best. 7558*/ 7559typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 7560struct sqlite3_pcache_methods2 { 7561 int iVersion; 7562 void *pArg; 7563 int (*xInit)(void*); 7564 void (*xShutdown)(void*); 7565 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 7566 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7567 int (*xPagecount)(sqlite3_pcache*); 7568 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7569 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 7570 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 7571 unsigned oldKey, unsigned newKey); 7572 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7573 void (*xDestroy)(sqlite3_pcache*); 7574 void (*xShrink)(sqlite3_pcache*); 7575}; 7576 7577/* 7578** This is the obsolete pcache_methods object that has now been replaced 7579** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 7580** retained in the header file for backwards compatibility only. 7581*/ 7582typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 7583struct sqlite3_pcache_methods { 7584 void *pArg; 7585 int (*xInit)(void*); 7586 void (*xShutdown)(void*); 7587 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 7588 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 7589 int (*xPagecount)(sqlite3_pcache*); 7590 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 7591 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 7592 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 7593 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 7594 void (*xDestroy)(sqlite3_pcache*); 7595}; 7596 7597 7598/* 7599** CAPI3REF: Online Backup Object 7600** 7601** The sqlite3_backup object records state information about an ongoing 7602** online backup operation. ^The sqlite3_backup object is created by 7603** a call to [sqlite3_backup_init()] and is destroyed by a call to 7604** [sqlite3_backup_finish()]. 7605** 7606** See Also: [Using the SQLite Online Backup API] 7607*/ 7608typedef struct sqlite3_backup sqlite3_backup; 7609 7610/* 7611** CAPI3REF: Online Backup API. 7612** 7613** The backup API copies the content of one database into another. 7614** It is useful either for creating backups of databases or 7615** for copying in-memory databases to or from persistent files. 7616** 7617** See Also: [Using the SQLite Online Backup API] 7618** 7619** ^SQLite holds a write transaction open on the destination database file 7620** for the duration of the backup operation. 7621** ^The source database is read-locked only while it is being read; 7622** it is not locked continuously for the entire backup operation. 7623** ^Thus, the backup may be performed on a live source database without 7624** preventing other database connections from 7625** reading or writing to the source database while the backup is underway. 7626** 7627** ^(To perform a backup operation: 7628** <ol> 7629** <li><b>sqlite3_backup_init()</b> is called once to initialize the 7630** backup, 7631** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 7632** the data between the two databases, and finally 7633** <li><b>sqlite3_backup_finish()</b> is called to release all resources 7634** associated with the backup operation. 7635** </ol>)^ 7636** There should be exactly one call to sqlite3_backup_finish() for each 7637** successful call to sqlite3_backup_init(). 7638** 7639** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 7640** 7641** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 7642** [database connection] associated with the destination database 7643** and the database name, respectively. 7644** ^The database name is "main" for the main database, "temp" for the 7645** temporary database, or the name specified after the AS keyword in 7646** an [ATTACH] statement for an attached database. 7647** ^The S and M arguments passed to 7648** sqlite3_backup_init(D,N,S,M) identify the [database connection] 7649** and database name of the source database, respectively. 7650** ^The source and destination [database connections] (parameters S and D) 7651** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 7652** an error. 7653** 7654** ^A call to sqlite3_backup_init() will fail, returning NULL, if 7655** there is already a read or read-write transaction open on the 7656** destination database. 7657** 7658** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 7659** returned and an error code and error message are stored in the 7660** destination [database connection] D. 7661** ^The error code and message for the failed call to sqlite3_backup_init() 7662** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 7663** [sqlite3_errmsg16()] functions. 7664** ^A successful call to sqlite3_backup_init() returns a pointer to an 7665** [sqlite3_backup] object. 7666** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 7667** sqlite3_backup_finish() functions to perform the specified backup 7668** operation. 7669** 7670** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 7671** 7672** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 7673** the source and destination databases specified by [sqlite3_backup] object B. 7674** ^If N is negative, all remaining source pages are copied. 7675** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 7676** are still more pages to be copied, then the function returns [SQLITE_OK]. 7677** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 7678** from source to destination, then it returns [SQLITE_DONE]. 7679** ^If an error occurs while running sqlite3_backup_step(B,N), 7680** then an [error code] is returned. ^As well as [SQLITE_OK] and 7681** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 7682** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 7683** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 7684** 7685** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 7686** <ol> 7687** <li> the destination database was opened read-only, or 7688** <li> the destination database is using write-ahead-log journaling 7689** and the destination and source page sizes differ, or 7690** <li> the destination database is an in-memory database and the 7691** destination and source page sizes differ. 7692** </ol>)^ 7693** 7694** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 7695** the [sqlite3_busy_handler | busy-handler function] 7696** is invoked (if one is specified). ^If the 7697** busy-handler returns non-zero before the lock is available, then 7698** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 7699** sqlite3_backup_step() can be retried later. ^If the source 7700** [database connection] 7701** is being used to write to the source database when sqlite3_backup_step() 7702** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 7703** case the call to sqlite3_backup_step() can be retried later on. ^(If 7704** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 7705** [SQLITE_READONLY] is returned, then 7706** there is no point in retrying the call to sqlite3_backup_step(). These 7707** errors are considered fatal.)^ The application must accept 7708** that the backup operation has failed and pass the backup operation handle 7709** to the sqlite3_backup_finish() to release associated resources. 7710** 7711** ^The first call to sqlite3_backup_step() obtains an exclusive lock 7712** on the destination file. ^The exclusive lock is not released until either 7713** sqlite3_backup_finish() is called or the backup operation is complete 7714** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 7715** sqlite3_backup_step() obtains a [shared lock] on the source database that 7716** lasts for the duration of the sqlite3_backup_step() call. 7717** ^Because the source database is not locked between calls to 7718** sqlite3_backup_step(), the source database may be modified mid-way 7719** through the backup process. ^If the source database is modified by an 7720** external process or via a database connection other than the one being 7721** used by the backup operation, then the backup will be automatically 7722** restarted by the next call to sqlite3_backup_step(). ^If the source 7723** database is modified by the using the same database connection as is used 7724** by the backup operation, then the backup database is automatically 7725** updated at the same time. 7726** 7727** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 7728** 7729** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 7730** application wishes to abandon the backup operation, the application 7731** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 7732** ^The sqlite3_backup_finish() interfaces releases all 7733** resources associated with the [sqlite3_backup] object. 7734** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 7735** active write-transaction on the destination database is rolled back. 7736** The [sqlite3_backup] object is invalid 7737** and may not be used following a call to sqlite3_backup_finish(). 7738** 7739** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 7740** sqlite3_backup_step() errors occurred, regardless or whether or not 7741** sqlite3_backup_step() completed. 7742** ^If an out-of-memory condition or IO error occurred during any prior 7743** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 7744** sqlite3_backup_finish() returns the corresponding [error code]. 7745** 7746** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 7747** is not a permanent error and does not affect the return value of 7748** sqlite3_backup_finish(). 7749** 7750** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 7751** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 7752** 7753** ^The sqlite3_backup_remaining() routine returns the number of pages still 7754** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 7755** ^The sqlite3_backup_pagecount() routine returns the total number of pages 7756** in the source database at the conclusion of the most recent 7757** sqlite3_backup_step(). 7758** ^(The values returned by these functions are only updated by 7759** sqlite3_backup_step(). If the source database is modified in a way that 7760** changes the size of the source database or the number of pages remaining, 7761** those changes are not reflected in the output of sqlite3_backup_pagecount() 7762** and sqlite3_backup_remaining() until after the next 7763** sqlite3_backup_step().)^ 7764** 7765** <b>Concurrent Usage of Database Handles</b> 7766** 7767** ^The source [database connection] may be used by the application for other 7768** purposes while a backup operation is underway or being initialized. 7769** ^If SQLite is compiled and configured to support threadsafe database 7770** connections, then the source database connection may be used concurrently 7771** from within other threads. 7772** 7773** However, the application must guarantee that the destination 7774** [database connection] is not passed to any other API (by any thread) after 7775** sqlite3_backup_init() is called and before the corresponding call to 7776** sqlite3_backup_finish(). SQLite does not currently check to see 7777** if the application incorrectly accesses the destination [database connection] 7778** and so no error code is reported, but the operations may malfunction 7779** nevertheless. Use of the destination database connection while a 7780** backup is in progress might also also cause a mutex deadlock. 7781** 7782** If running in [shared cache mode], the application must 7783** guarantee that the shared cache used by the destination database 7784** is not accessed while the backup is running. In practice this means 7785** that the application must guarantee that the disk file being 7786** backed up to is not accessed by any connection within the process, 7787** not just the specific connection that was passed to sqlite3_backup_init(). 7788** 7789** The [sqlite3_backup] object itself is partially threadsafe. Multiple 7790** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 7791** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 7792** APIs are not strictly speaking threadsafe. If they are invoked at the 7793** same time as another thread is invoking sqlite3_backup_step() it is 7794** possible that they return invalid values. 7795*/ 7796sqlite3_backup *sqlite3_backup_init( 7797 sqlite3 *pDest, /* Destination database handle */ 7798 const char *zDestName, /* Destination database name */ 7799 sqlite3 *pSource, /* Source database handle */ 7800 const char *zSourceName /* Source database name */ 7801); 7802int sqlite3_backup_step(sqlite3_backup *p, int nPage); 7803int sqlite3_backup_finish(sqlite3_backup *p); 7804int sqlite3_backup_remaining(sqlite3_backup *p); 7805int sqlite3_backup_pagecount(sqlite3_backup *p); 7806 7807/* 7808** CAPI3REF: Unlock Notification 7809** METHOD: sqlite3 7810** 7811** ^When running in shared-cache mode, a database operation may fail with 7812** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 7813** individual tables within the shared-cache cannot be obtained. See 7814** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 7815** ^This API may be used to register a callback that SQLite will invoke 7816** when the connection currently holding the required lock relinquishes it. 7817** ^This API is only available if the library was compiled with the 7818** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 7819** 7820** See Also: [Using the SQLite Unlock Notification Feature]. 7821** 7822** ^Shared-cache locks are released when a database connection concludes 7823** its current transaction, either by committing it or rolling it back. 7824** 7825** ^When a connection (known as the blocked connection) fails to obtain a 7826** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 7827** identity of the database connection (the blocking connection) that 7828** has locked the required resource is stored internally. ^After an 7829** application receives an SQLITE_LOCKED error, it may call the 7830** sqlite3_unlock_notify() method with the blocked connection handle as 7831** the first argument to register for a callback that will be invoked 7832** when the blocking connections current transaction is concluded. ^The 7833** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 7834** call that concludes the blocking connections transaction. 7835** 7836** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 7837** there is a chance that the blocking connection will have already 7838** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 7839** If this happens, then the specified callback is invoked immediately, 7840** from within the call to sqlite3_unlock_notify().)^ 7841** 7842** ^If the blocked connection is attempting to obtain a write-lock on a 7843** shared-cache table, and more than one other connection currently holds 7844** a read-lock on the same table, then SQLite arbitrarily selects one of 7845** the other connections to use as the blocking connection. 7846** 7847** ^(There may be at most one unlock-notify callback registered by a 7848** blocked connection. If sqlite3_unlock_notify() is called when the 7849** blocked connection already has a registered unlock-notify callback, 7850** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 7851** called with a NULL pointer as its second argument, then any existing 7852** unlock-notify callback is canceled. ^The blocked connections 7853** unlock-notify callback may also be canceled by closing the blocked 7854** connection using [sqlite3_close()]. 7855** 7856** The unlock-notify callback is not reentrant. If an application invokes 7857** any sqlite3_xxx API functions from within an unlock-notify callback, a 7858** crash or deadlock may be the result. 7859** 7860** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 7861** returns SQLITE_OK. 7862** 7863** <b>Callback Invocation Details</b> 7864** 7865** When an unlock-notify callback is registered, the application provides a 7866** single void* pointer that is passed to the callback when it is invoked. 7867** However, the signature of the callback function allows SQLite to pass 7868** it an array of void* context pointers. The first argument passed to 7869** an unlock-notify callback is a pointer to an array of void* pointers, 7870** and the second is the number of entries in the array. 7871** 7872** When a blocking connections transaction is concluded, there may be 7873** more than one blocked connection that has registered for an unlock-notify 7874** callback. ^If two or more such blocked connections have specified the 7875** same callback function, then instead of invoking the callback function 7876** multiple times, it is invoked once with the set of void* context pointers 7877** specified by the blocked connections bundled together into an array. 7878** This gives the application an opportunity to prioritize any actions 7879** related to the set of unblocked database connections. 7880** 7881** <b>Deadlock Detection</b> 7882** 7883** Assuming that after registering for an unlock-notify callback a 7884** database waits for the callback to be issued before taking any further 7885** action (a reasonable assumption), then using this API may cause the 7886** application to deadlock. For example, if connection X is waiting for 7887** connection Y's transaction to be concluded, and similarly connection 7888** Y is waiting on connection X's transaction, then neither connection 7889** will proceed and the system may remain deadlocked indefinitely. 7890** 7891** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 7892** detection. ^If a given call to sqlite3_unlock_notify() would put the 7893** system in a deadlocked state, then SQLITE_LOCKED is returned and no 7894** unlock-notify callback is registered. The system is said to be in 7895** a deadlocked state if connection A has registered for an unlock-notify 7896** callback on the conclusion of connection B's transaction, and connection 7897** B has itself registered for an unlock-notify callback when connection 7898** A's transaction is concluded. ^Indirect deadlock is also detected, so 7899** the system is also considered to be deadlocked if connection B has 7900** registered for an unlock-notify callback on the conclusion of connection 7901** C's transaction, where connection C is waiting on connection A. ^Any 7902** number of levels of indirection are allowed. 7903** 7904** <b>The "DROP TABLE" Exception</b> 7905** 7906** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 7907** always appropriate to call sqlite3_unlock_notify(). There is however, 7908** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 7909** SQLite checks if there are any currently executing SELECT statements 7910** that belong to the same connection. If there are, SQLITE_LOCKED is 7911** returned. In this case there is no "blocking connection", so invoking 7912** sqlite3_unlock_notify() results in the unlock-notify callback being 7913** invoked immediately. If the application then re-attempts the "DROP TABLE" 7914** or "DROP INDEX" query, an infinite loop might be the result. 7915** 7916** One way around this problem is to check the extended error code returned 7917** by an sqlite3_step() call. ^(If there is a blocking connection, then the 7918** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 7919** the special "DROP TABLE/INDEX" case, the extended error code is just 7920** SQLITE_LOCKED.)^ 7921*/ 7922int sqlite3_unlock_notify( 7923 sqlite3 *pBlocked, /* Waiting connection */ 7924 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 7925 void *pNotifyArg /* Argument to pass to xNotify */ 7926); 7927 7928 7929/* 7930** CAPI3REF: String Comparison 7931** 7932** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 7933** and extensions to compare the contents of two buffers containing UTF-8 7934** strings in a case-independent fashion, using the same definition of "case 7935** independence" that SQLite uses internally when comparing identifiers. 7936*/ 7937int sqlite3_stricmp(const char *, const char *); 7938int sqlite3_strnicmp(const char *, const char *, int); 7939 7940/* 7941** CAPI3REF: String Globbing 7942* 7943** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 7944** string X matches the [GLOB] pattern P. 7945** ^The definition of [GLOB] pattern matching used in 7946** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 7947** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 7948** is case sensitive. 7949** 7950** Note that this routine returns zero on a match and non-zero if the strings 7951** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7952** 7953** See also: [sqlite3_strlike()]. 7954*/ 7955int sqlite3_strglob(const char *zGlob, const char *zStr); 7956 7957/* 7958** CAPI3REF: String LIKE Matching 7959* 7960** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 7961** string X matches the [LIKE] pattern P with escape character E. 7962** ^The definition of [LIKE] pattern matching used in 7963** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 7964** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 7965** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 7966** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 7967** insensitive - equivalent upper and lower case ASCII characters match 7968** one another. 7969** 7970** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 7971** only ASCII characters are case folded. 7972** 7973** Note that this routine returns zero on a match and non-zero if the strings 7974** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 7975** 7976** See also: [sqlite3_strglob()]. 7977*/ 7978int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 7979 7980/* 7981** CAPI3REF: Error Logging Interface 7982** 7983** ^The [sqlite3_log()] interface writes a message into the [error log] 7984** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 7985** ^If logging is enabled, the zFormat string and subsequent arguments are 7986** used with [sqlite3_snprintf()] to generate the final output string. 7987** 7988** The sqlite3_log() interface is intended for use by extensions such as 7989** virtual tables, collating functions, and SQL functions. While there is 7990** nothing to prevent an application from calling sqlite3_log(), doing so 7991** is considered bad form. 7992** 7993** The zFormat string must not be NULL. 7994** 7995** To avoid deadlocks and other threading problems, the sqlite3_log() routine 7996** will not use dynamically allocated memory. The log message is stored in 7997** a fixed-length buffer on the stack. If the log message is longer than 7998** a few hundred characters, it will be truncated to the length of the 7999** buffer. 8000*/ 8001void sqlite3_log(int iErrCode, const char *zFormat, ...); 8002 8003/* 8004** CAPI3REF: Write-Ahead Log Commit Hook 8005** METHOD: sqlite3 8006** 8007** ^The [sqlite3_wal_hook()] function is used to register a callback that 8008** is invoked each time data is committed to a database in wal mode. 8009** 8010** ^(The callback is invoked by SQLite after the commit has taken place and 8011** the associated write-lock on the database released)^, so the implementation 8012** may read, write or [checkpoint] the database as required. 8013** 8014** ^The first parameter passed to the callback function when it is invoked 8015** is a copy of the third parameter passed to sqlite3_wal_hook() when 8016** registering the callback. ^The second is a copy of the database handle. 8017** ^The third parameter is the name of the database that was written to - 8018** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8019** is the number of pages currently in the write-ahead log file, 8020** including those that were just committed. 8021** 8022** The callback function should normally return [SQLITE_OK]. ^If an error 8023** code is returned, that error will propagate back up through the 8024** SQLite code base to cause the statement that provoked the callback 8025** to report an error, though the commit will have still occurred. If the 8026** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8027** that does not correspond to any valid SQLite error code, the results 8028** are undefined. 8029** 8030** A single database handle may have at most a single write-ahead log callback 8031** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8032** previously registered write-ahead log callback. ^Note that the 8033** [sqlite3_wal_autocheckpoint()] interface and the 8034** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8035** overwrite any prior [sqlite3_wal_hook()] settings. 8036*/ 8037void *sqlite3_wal_hook( 8038 sqlite3*, 8039 int(*)(void *,sqlite3*,const char*,int), 8040 void* 8041); 8042 8043/* 8044** CAPI3REF: Configure an auto-checkpoint 8045** METHOD: sqlite3 8046** 8047** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8048** [sqlite3_wal_hook()] that causes any database on [database connection] D 8049** to automatically [checkpoint] 8050** after committing a transaction if there are N or 8051** more frames in the [write-ahead log] file. ^Passing zero or 8052** a negative value as the nFrame parameter disables automatic 8053** checkpoints entirely. 8054** 8055** ^The callback registered by this function replaces any existing callback 8056** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8057** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8058** configured by this function. 8059** 8060** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8061** from SQL. 8062** 8063** ^Checkpoints initiated by this mechanism are 8064** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8065** 8066** ^Every new [database connection] defaults to having the auto-checkpoint 8067** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8068** pages. The use of this interface 8069** is only necessary if the default setting is found to be suboptimal 8070** for a particular application. 8071*/ 8072int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8073 8074/* 8075** CAPI3REF: Checkpoint a database 8076** METHOD: sqlite3 8077** 8078** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8079** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8080** 8081** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8082** [write-ahead log] for database X on [database connection] D to be 8083** transferred into the database file and for the write-ahead log to 8084** be reset. See the [checkpointing] documentation for addition 8085** information. 8086** 8087** This interface used to be the only way to cause a checkpoint to 8088** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8089** interface was added. This interface is retained for backwards 8090** compatibility and as a convenience for applications that need to manually 8091** start a callback but which do not need the full power (and corresponding 8092** complication) of [sqlite3_wal_checkpoint_v2()]. 8093*/ 8094int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8095 8096/* 8097** CAPI3REF: Checkpoint a database 8098** METHOD: sqlite3 8099** 8100** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8101** operation on database X of [database connection] D in mode M. Status 8102** information is written back into integers pointed to by L and C.)^ 8103** ^(The M parameter must be a valid [checkpoint mode]:)^ 8104** 8105** <dl> 8106** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8107** ^Checkpoint as many frames as possible without waiting for any database 8108** readers or writers to finish, then sync the database file if all frames 8109** in the log were checkpointed. ^The [busy-handler callback] 8110** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8111** ^On the other hand, passive mode might leave the checkpoint unfinished 8112** if there are concurrent readers or writers. 8113** 8114** <dt>SQLITE_CHECKPOINT_FULL<dd> 8115** ^This mode blocks (it invokes the 8116** [sqlite3_busy_handler|busy-handler callback]) until there is no 8117** database writer and all readers are reading from the most recent database 8118** snapshot. ^It then checkpoints all frames in the log file and syncs the 8119** database file. ^This mode blocks new database writers while it is pending, 8120** but new database readers are allowed to continue unimpeded. 8121** 8122** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8123** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8124** that after checkpointing the log file it blocks (calls the 8125** [busy-handler callback]) 8126** until all readers are reading from the database file only. ^This ensures 8127** that the next writer will restart the log file from the beginning. 8128** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8129** database writer attempts while it is pending, but does not impede readers. 8130** 8131** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8132** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8133** addition that it also truncates the log file to zero bytes just prior 8134** to a successful return. 8135** </dl> 8136** 8137** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8138** the log file or to -1 if the checkpoint could not run because 8139** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8140** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8141** log file (including any that were already checkpointed before the function 8142** was called) or to -1 if the checkpoint could not run due to an error or 8143** because the database is not in WAL mode. ^Note that upon successful 8144** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8145** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8146** 8147** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8148** any other process is running a checkpoint operation at the same time, the 8149** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8150** busy-handler configured, it will not be invoked in this case. 8151** 8152** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8153** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8154** obtained immediately, and a busy-handler is configured, it is invoked and 8155** the writer lock retried until either the busy-handler returns 0 or the lock 8156** is successfully obtained. ^The busy-handler is also invoked while waiting for 8157** database readers as described above. ^If the busy-handler returns 0 before 8158** the writer lock is obtained or while waiting for database readers, the 8159** checkpoint operation proceeds from that point in the same way as 8160** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8161** without blocking any further. ^SQLITE_BUSY is returned in this case. 8162** 8163** ^If parameter zDb is NULL or points to a zero length string, then the 8164** specified operation is attempted on all WAL databases [attached] to 8165** [database connection] db. In this case the 8166** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8167** an SQLITE_BUSY error is encountered when processing one or more of the 8168** attached WAL databases, the operation is still attempted on any remaining 8169** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8170** error occurs while processing an attached database, processing is abandoned 8171** and the error code is returned to the caller immediately. ^If no error 8172** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8173** databases, SQLITE_OK is returned. 8174** 8175** ^If database zDb is the name of an attached database that is not in WAL 8176** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8177** zDb is not NULL (or a zero length string) and is not the name of any 8178** attached database, SQLITE_ERROR is returned to the caller. 8179** 8180** ^Unless it returns SQLITE_MISUSE, 8181** the sqlite3_wal_checkpoint_v2() interface 8182** sets the error information that is queried by 8183** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8184** 8185** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8186** from SQL. 8187*/ 8188int sqlite3_wal_checkpoint_v2( 8189 sqlite3 *db, /* Database handle */ 8190 const char *zDb, /* Name of attached database (or NULL) */ 8191 int eMode, /* SQLITE_CHECKPOINT_* value */ 8192 int *pnLog, /* OUT: Size of WAL log in frames */ 8193 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8194); 8195 8196/* 8197** CAPI3REF: Checkpoint Mode Values 8198** KEYWORDS: {checkpoint mode} 8199** 8200** These constants define all valid values for the "checkpoint mode" passed 8201** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8202** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8203** meaning of each of these checkpoint modes. 8204*/ 8205#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8206#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8207#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8208#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8209 8210/* 8211** CAPI3REF: Virtual Table Interface Configuration 8212** 8213** This function may be called by either the [xConnect] or [xCreate] method 8214** of a [virtual table] implementation to configure 8215** various facets of the virtual table interface. 8216** 8217** If this interface is invoked outside the context of an xConnect or 8218** xCreate virtual table method then the behavior is undefined. 8219** 8220** At present, there is only one option that may be configured using 8221** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8222** may be added in the future. 8223*/ 8224int sqlite3_vtab_config(sqlite3*, int op, ...); 8225 8226/* 8227** CAPI3REF: Virtual Table Configuration Options 8228** 8229** These macros define the various options to the 8230** [sqlite3_vtab_config()] interface that [virtual table] implementations 8231** can use to customize and optimize their behavior. 8232** 8233** <dl> 8234** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8235** <dd>Calls of the form 8236** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8237** where X is an integer. If X is zero, then the [virtual table] whose 8238** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8239** support constraints. In this configuration (which is the default) if 8240** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8241** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8242** specified as part of the users SQL statement, regardless of the actual 8243** ON CONFLICT mode specified. 8244** 8245** If X is non-zero, then the virtual table implementation guarantees 8246** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8247** any modifications to internal or persistent data structures have been made. 8248** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8249** is able to roll back a statement or database transaction, and abandon 8250** or continue processing the current SQL statement as appropriate. 8251** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8252** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8253** had been ABORT. 8254** 8255** Virtual table implementations that are required to handle OR REPLACE 8256** must do so within the [xUpdate] method. If a call to the 8257** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8258** CONFLICT policy is REPLACE, the virtual table implementation should 8259** silently replace the appropriate rows within the xUpdate callback and 8260** return SQLITE_OK. Or, if this is not possible, it may return 8261** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8262** constraint handling. 8263** </dl> 8264*/ 8265#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8266 8267/* 8268** CAPI3REF: Determine The Virtual Table Conflict Policy 8269** 8270** This function may only be called from within a call to the [xUpdate] method 8271** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8272** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8273** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8274** of the SQL statement that triggered the call to the [xUpdate] method of the 8275** [virtual table]. 8276*/ 8277int sqlite3_vtab_on_conflict(sqlite3 *); 8278 8279/* 8280** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 8281** 8282** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 8283** method of a [virtual table], then it returns true if and only if the 8284** column is being fetched as part of an UPDATE operation during which the 8285** column value will not change. Applications might use this to substitute 8286** a lighter-weight value to return that the corresponding [xUpdate] method 8287** understands as a "no-change" value. 8288** 8289** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 8290** the column is not changed by the UPDATE statement, they the xColumn 8291** method can optionally return without setting a result, without calling 8292** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 8293** In that case, [sqlite3_value_nochange(X)] will return true for the 8294** same column in the [xUpdate] method. 8295*/ 8296int sqlite3_vtab_nochange(sqlite3_context*); 8297 8298/* 8299** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8300** 8301** This function may only be called from within a call to the [xBestIndex] 8302** method of a [virtual table]. 8303** 8304** The first argument must be the sqlite3_index_info object that is the 8305** first parameter to the xBestIndex() method. The second argument must be 8306** an index into the aConstraint[] array belonging to the sqlite3_index_info 8307** structure passed to xBestIndex. This function returns a pointer to a buffer 8308** containing the name of the collation sequence for the corresponding 8309** constraint. 8310*/ 8311SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8312 8313/* 8314** CAPI3REF: Conflict resolution modes 8315** KEYWORDS: {conflict resolution mode} 8316** 8317** These constants are returned by [sqlite3_vtab_on_conflict()] to 8318** inform a [virtual table] implementation what the [ON CONFLICT] mode 8319** is for the SQL statement being evaluated. 8320** 8321** Note that the [SQLITE_IGNORE] constant is also used as a potential 8322** return value from the [sqlite3_set_authorizer()] callback and that 8323** [SQLITE_ABORT] is also a [result code]. 8324*/ 8325#define SQLITE_ROLLBACK 1 8326/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8327#define SQLITE_FAIL 3 8328/* #define SQLITE_ABORT 4 // Also an error code */ 8329#define SQLITE_REPLACE 5 8330 8331/* 8332** CAPI3REF: Prepared Statement Scan Status Opcodes 8333** KEYWORDS: {scanstatus options} 8334** 8335** The following constants can be used for the T parameter to the 8336** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8337** different metric for sqlite3_stmt_scanstatus() to return. 8338** 8339** When the value returned to V is a string, space to hold that string is 8340** managed by the prepared statement S and will be automatically freed when 8341** S is finalized. 8342** 8343** <dl> 8344** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8345** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8346** set to the total number of times that the X-th loop has run.</dd> 8347** 8348** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8349** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8350** to the total number of rows examined by all iterations of the X-th loop.</dd> 8351** 8352** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8353** <dd>^The "double" variable pointed to by the T parameter will be set to the 8354** query planner's estimate for the average number of rows output from each 8355** iteration of the X-th loop. If the query planner's estimates was accurate, 8356** then this value will approximate the quotient NVISIT/NLOOP and the 8357** product of this value for all prior loops with the same SELECTID will 8358** be the NLOOP value for the current loop. 8359** 8360** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8361** <dd>^The "const char *" variable pointed to by the T parameter will be set 8362** to a zero-terminated UTF-8 string containing the name of the index or table 8363** used for the X-th loop. 8364** 8365** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8366** <dd>^The "const char *" variable pointed to by the T parameter will be set 8367** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8368** description for the X-th loop. 8369** 8370** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8371** <dd>^The "int" variable pointed to by the T parameter will be set to the 8372** "select-id" for the X-th loop. The select-id identifies which query or 8373** subquery the loop is part of. The main query has a select-id of zero. 8374** The select-id is the same value as is output in the first column 8375** of an [EXPLAIN QUERY PLAN] query. 8376** </dl> 8377*/ 8378#define SQLITE_SCANSTAT_NLOOP 0 8379#define SQLITE_SCANSTAT_NVISIT 1 8380#define SQLITE_SCANSTAT_EST 2 8381#define SQLITE_SCANSTAT_NAME 3 8382#define SQLITE_SCANSTAT_EXPLAIN 4 8383#define SQLITE_SCANSTAT_SELECTID 5 8384 8385/* 8386** CAPI3REF: Prepared Statement Scan Status 8387** METHOD: sqlite3_stmt 8388** 8389** This interface returns information about the predicted and measured 8390** performance for pStmt. Advanced applications can use this 8391** interface to compare the predicted and the measured performance and 8392** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8393** 8394** Since this interface is expected to be rarely used, it is only 8395** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8396** compile-time option. 8397** 8398** The "iScanStatusOp" parameter determines which status information to return. 8399** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8400** of this interface is undefined. 8401** ^The requested measurement is written into a variable pointed to by 8402** the "pOut" parameter. 8403** Parameter "idx" identifies the specific loop to retrieve statistics for. 8404** Loops are numbered starting from zero. ^If idx is out of range - less than 8405** zero or greater than or equal to the total number of loops used to implement 8406** the statement - a non-zero value is returned and the variable that pOut 8407** points to is unchanged. 8408** 8409** ^Statistics might not be available for all loops in all statements. ^In cases 8410** where there exist loops with no available statistics, this function behaves 8411** as if the loop did not exist - it returns non-zero and leave the variable 8412** that pOut points to unchanged. 8413** 8414** See also: [sqlite3_stmt_scanstatus_reset()] 8415*/ 8416int sqlite3_stmt_scanstatus( 8417 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8418 int idx, /* Index of loop to report on */ 8419 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8420 void *pOut /* Result written here */ 8421); 8422 8423/* 8424** CAPI3REF: Zero Scan-Status Counters 8425** METHOD: sqlite3_stmt 8426** 8427** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8428** 8429** This API is only available if the library is built with pre-processor 8430** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8431*/ 8432void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8433 8434/* 8435** CAPI3REF: Flush caches to disk mid-transaction 8436** 8437** ^If a write-transaction is open on [database connection] D when the 8438** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8439** pages in the pager-cache that are not currently in use are written out 8440** to disk. A dirty page may be in use if a database cursor created by an 8441** active SQL statement is reading from it, or if it is page 1 of a database 8442** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8443** interface flushes caches for all schemas - "main", "temp", and 8444** any [attached] databases. 8445** 8446** ^If this function needs to obtain extra database locks before dirty pages 8447** can be flushed to disk, it does so. ^If those locks cannot be obtained 8448** immediately and there is a busy-handler callback configured, it is invoked 8449** in the usual manner. ^If the required lock still cannot be obtained, then 8450** the database is skipped and an attempt made to flush any dirty pages 8451** belonging to the next (if any) database. ^If any databases are skipped 8452** because locks cannot be obtained, but no other error occurs, this 8453** function returns SQLITE_BUSY. 8454** 8455** ^If any other error occurs while flushing dirty pages to disk (for 8456** example an IO error or out-of-memory condition), then processing is 8457** abandoned and an SQLite [error code] is returned to the caller immediately. 8458** 8459** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8460** 8461** ^This function does not set the database handle error code or message 8462** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8463*/ 8464int sqlite3_db_cacheflush(sqlite3*); 8465 8466/* 8467** CAPI3REF: The pre-update hook. 8468** 8469** ^These interfaces are only available if SQLite is compiled using the 8470** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8471** 8472** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8473** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8474** on a database table. 8475** ^At most one preupdate hook may be registered at a time on a single 8476** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8477** the previous setting. 8478** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8479** with a NULL pointer as the second parameter. 8480** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8481** the first parameter to callbacks. 8482** 8483** ^The preupdate hook only fires for changes to real database tables; the 8484** preupdate hook is not invoked for changes to [virtual tables] or to 8485** system tables like sqlite_master or sqlite_stat1. 8486** 8487** ^The second parameter to the preupdate callback is a pointer to 8488** the [database connection] that registered the preupdate hook. 8489** ^The third parameter to the preupdate callback is one of the constants 8490** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8491** kind of update operation that is about to occur. 8492** ^(The fourth parameter to the preupdate callback is the name of the 8493** database within the database connection that is being modified. This 8494** will be "main" for the main database or "temp" for TEMP tables or 8495** the name given after the AS keyword in the [ATTACH] statement for attached 8496** databases.)^ 8497** ^The fifth parameter to the preupdate callback is the name of the 8498** table that is being modified. 8499** 8500** For an UPDATE or DELETE operation on a [rowid table], the sixth 8501** parameter passed to the preupdate callback is the initial [rowid] of the 8502** row being modified or deleted. For an INSERT operation on a rowid table, 8503** or any operation on a WITHOUT ROWID table, the value of the sixth 8504** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8505** seventh parameter is the final rowid value of the row being inserted 8506** or updated. The value of the seventh parameter passed to the callback 8507** function is not defined for operations on WITHOUT ROWID tables, or for 8508** INSERT operations on rowid tables. 8509** 8510** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8511** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8512** provide additional information about a preupdate event. These routines 8513** may only be called from within a preupdate callback. Invoking any of 8514** these routines from outside of a preupdate callback or with a 8515** [database connection] pointer that is different from the one supplied 8516** to the preupdate callback results in undefined and probably undesirable 8517** behavior. 8518** 8519** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8520** in the row that is being inserted, updated, or deleted. 8521** 8522** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8523** a [protected sqlite3_value] that contains the value of the Nth column of 8524** the table row before it is updated. The N parameter must be between 0 8525** and one less than the number of columns or the behavior will be 8526** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8527** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8528** behavior is undefined. The [sqlite3_value] that P points to 8529** will be destroyed when the preupdate callback returns. 8530** 8531** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 8532** a [protected sqlite3_value] that contains the value of the Nth column of 8533** the table row after it is updated. The N parameter must be between 0 8534** and one less than the number of columns or the behavior will be 8535** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 8536** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 8537** behavior is undefined. The [sqlite3_value] that P points to 8538** will be destroyed when the preupdate callback returns. 8539** 8540** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 8541** callback was invoked as a result of a direct insert, update, or delete 8542** operation; or 1 for inserts, updates, or deletes invoked by top-level 8543** triggers; or 2 for changes resulting from triggers called by top-level 8544** triggers; and so forth. 8545** 8546** See also: [sqlite3_update_hook()] 8547*/ 8548#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 8549void *sqlite3_preupdate_hook( 8550 sqlite3 *db, 8551 void(*xPreUpdate)( 8552 void *pCtx, /* Copy of third arg to preupdate_hook() */ 8553 sqlite3 *db, /* Database handle */ 8554 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 8555 char const *zDb, /* Database name */ 8556 char const *zName, /* Table name */ 8557 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 8558 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 8559 ), 8560 void* 8561); 8562int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 8563int sqlite3_preupdate_count(sqlite3 *); 8564int sqlite3_preupdate_depth(sqlite3 *); 8565int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 8566#endif 8567 8568/* 8569** CAPI3REF: Low-level system error code 8570** 8571** ^Attempt to return the underlying operating system error code or error 8572** number that caused the most recent I/O error or failure to open a file. 8573** The return value is OS-dependent. For example, on unix systems, after 8574** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 8575** called to get back the underlying "errno" that caused the problem, such 8576** as ENOSPC, EAUTH, EISDIR, and so forth. 8577*/ 8578int sqlite3_system_errno(sqlite3*); 8579 8580/* 8581** CAPI3REF: Database Snapshot 8582** KEYWORDS: {snapshot} {sqlite3_snapshot} 8583** EXPERIMENTAL 8584** 8585** An instance of the snapshot object records the state of a [WAL mode] 8586** database for some specific point in history. 8587** 8588** In [WAL mode], multiple [database connections] that are open on the 8589** same database file can each be reading a different historical version 8590** of the database file. When a [database connection] begins a read 8591** transaction, that connection sees an unchanging copy of the database 8592** as it existed for the point in time when the transaction first started. 8593** Subsequent changes to the database from other connections are not seen 8594** by the reader until a new read transaction is started. 8595** 8596** The sqlite3_snapshot object records state information about an historical 8597** version of the database file so that it is possible to later open a new read 8598** transaction that sees that historical version of the database rather than 8599** the most recent version. 8600** 8601** The constructor for this object is [sqlite3_snapshot_get()]. The 8602** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer 8603** to an historical snapshot (if possible). The destructor for 8604** sqlite3_snapshot objects is [sqlite3_snapshot_free()]. 8605*/ 8606typedef struct sqlite3_snapshot { 8607 unsigned char hidden[48]; 8608} sqlite3_snapshot; 8609 8610/* 8611** CAPI3REF: Record A Database Snapshot 8612** EXPERIMENTAL 8613** 8614** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 8615** new [sqlite3_snapshot] object that records the current state of 8616** schema S in database connection D. ^On success, the 8617** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 8618** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 8619** If there is not already a read-transaction open on schema S when 8620** this function is called, one is opened automatically. 8621** 8622** The following must be true for this function to succeed. If any of 8623** the following statements are false when sqlite3_snapshot_get() is 8624** called, SQLITE_ERROR is returned. The final value of *P is undefined 8625** in this case. 8626** 8627** <ul> 8628** <li> The database handle must be in [autocommit mode]. 8629** 8630** <li> Schema S of [database connection] D must be a [WAL mode] database. 8631** 8632** <li> There must not be a write transaction open on schema S of database 8633** connection D. 8634** 8635** <li> One or more transactions must have been written to the current wal 8636** file since it was created on disk (by any connection). This means 8637** that a snapshot cannot be taken on a wal mode database with no wal 8638** file immediately after it is first opened. At least one transaction 8639** must be written to it first. 8640** </ul> 8641** 8642** This function may also return SQLITE_NOMEM. If it is called with the 8643** database handle in autocommit mode but fails for some other reason, 8644** whether or not a read transaction is opened on schema S is undefined. 8645** 8646** The [sqlite3_snapshot] object returned from a successful call to 8647** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 8648** to avoid a memory leak. 8649** 8650** The [sqlite3_snapshot_get()] interface is only available when the 8651** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8652*/ 8653SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 8654 sqlite3 *db, 8655 const char *zSchema, 8656 sqlite3_snapshot **ppSnapshot 8657); 8658 8659/* 8660** CAPI3REF: Start a read transaction on an historical snapshot 8661** EXPERIMENTAL 8662** 8663** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a 8664** read transaction for schema S of 8665** [database connection] D such that the read transaction 8666** refers to historical [snapshot] P, rather than the most 8667** recent change to the database. 8668** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success 8669** or an appropriate [error code] if it fails. 8670** 8671** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be 8672** the first operation following the [BEGIN] that takes the schema S 8673** out of [autocommit mode]. 8674** ^In other words, schema S must not currently be in 8675** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the 8676** database connection D must be out of [autocommit mode]. 8677** ^A [snapshot] will fail to open if it has been overwritten by a 8678** [checkpoint]. 8679** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 8680** database connection D does not know that the database file for 8681** schema S is in [WAL mode]. A database connection might not know 8682** that the database file is in [WAL mode] if there has been no prior 8683** I/O on that database connection, or if the database entered [WAL mode] 8684** after the most recent I/O on the database connection.)^ 8685** (Hint: Run "[PRAGMA application_id]" against a newly opened 8686** database connection in order to make it ready to use snapshots.) 8687** 8688** The [sqlite3_snapshot_open()] interface is only available when the 8689** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8690*/ 8691SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 8692 sqlite3 *db, 8693 const char *zSchema, 8694 sqlite3_snapshot *pSnapshot 8695); 8696 8697/* 8698** CAPI3REF: Destroy a snapshot 8699** EXPERIMENTAL 8700** 8701** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 8702** The application must eventually free every [sqlite3_snapshot] object 8703** using this routine to avoid a memory leak. 8704** 8705** The [sqlite3_snapshot_free()] interface is only available when the 8706** SQLITE_ENABLE_SNAPSHOT compile-time option is used. 8707*/ 8708SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 8709 8710/* 8711** CAPI3REF: Compare the ages of two snapshot handles. 8712** EXPERIMENTAL 8713** 8714** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 8715** of two valid snapshot handles. 8716** 8717** If the two snapshot handles are not associated with the same database 8718** file, the result of the comparison is undefined. 8719** 8720** Additionally, the result of the comparison is only valid if both of the 8721** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 8722** last time the wal file was deleted. The wal file is deleted when the 8723** database is changed back to rollback mode or when the number of database 8724** clients drops to zero. If either snapshot handle was obtained before the 8725** wal file was last deleted, the value returned by this function 8726** is undefined. 8727** 8728** Otherwise, this API returns a negative value if P1 refers to an older 8729** snapshot than P2, zero if the two handles refer to the same database 8730** snapshot, and a positive value if P1 is a newer snapshot than P2. 8731*/ 8732SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 8733 sqlite3_snapshot *p1, 8734 sqlite3_snapshot *p2 8735); 8736 8737/* 8738** CAPI3REF: Recover snapshots from a wal file 8739** EXPERIMENTAL 8740** 8741** If all connections disconnect from a database file but do not perform 8742** a checkpoint, the existing wal file is opened along with the database 8743** file the next time the database is opened. At this point it is only 8744** possible to successfully call sqlite3_snapshot_open() to open the most 8745** recent snapshot of the database (the one at the head of the wal file), 8746** even though the wal file may contain other valid snapshots for which 8747** clients have sqlite3_snapshot handles. 8748** 8749** This function attempts to scan the wal file associated with database zDb 8750** of database handle db and make all valid snapshots available to 8751** sqlite3_snapshot_open(). It is an error if there is already a read 8752** transaction open on the database, or if the database is not a wal mode 8753** database. 8754** 8755** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 8756*/ 8757SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 8758 8759/* 8760** CAPI3REF: Serialize a database 8761** 8762** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 8763** that is a serialization of the S database on [database connection] D. 8764** If P is not a NULL pointer, then the size of the database in bytes 8765** is written into *P. 8766** 8767** For an ordinary on-disk database file, the serialization is just a 8768** copy of the disk file. For an in-memory database or a "TEMP" database, 8769** the serialization is the same sequence of bytes which would be written 8770** to disk if that database where backed up to disk. 8771** 8772** The usual case is that sqlite3_serialize() copies the serialization of 8773** the database into memory obtained from [sqlite3_malloc64()] and returns 8774** a pointer to that memory. The caller is responsible for freeing the 8775** returned value to avoid a memory leak. However, if the F argument 8776** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 8777** are made, and the sqlite3_serialize() function will return a pointer 8778** to the contiguous memory representation of the database that SQLite 8779** is currently using for that database, or NULL if the no such contiguous 8780** memory representation of the database exists. A contiguous memory 8781** representation of the database will usually only exist if there has 8782** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 8783** values of D and S. 8784** The size of the database is written into *P even if the 8785** SQLITE_SERIALIZE_NOCOPY bit is set but no contigious copy 8786** of the database exists. 8787** 8788** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 8789** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 8790** allocation error occurs. 8791** 8792** This interface is only available if SQLite is compiled with the 8793** [SQLITE_ENABLE_DESERIALIZE] option. 8794*/ 8795unsigned char *sqlite3_serialize( 8796 sqlite3 *db, /* The database connection */ 8797 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 8798 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 8799 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 8800); 8801 8802/* 8803** CAPI3REF: Flags for sqlite3_serialize 8804** 8805** Zero or more of the following constants can be OR-ed together for 8806** the F argument to [sqlite3_serialize(D,S,P,F)]. 8807** 8808** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 8809** a pointer to contiguous in-memory database that it is currently using, 8810** without making a copy of the database. If SQLite is not currently using 8811** a contiguous in-memory database, then this option causes 8812** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 8813** using a contiguous in-memory database if it has been initialized by a 8814** prior call to [sqlite3_deserialize()]. 8815*/ 8816#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 8817 8818/* 8819** CAPI3REF: Deserialize a database 8820** 8821** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 8822** [database connection] D to disconnect from database S and then 8823** reopen S as an in-memory database based on the serialization contained 8824** in P. The serialized database P is N bytes in size. M is the size of 8825** the buffer P, which might be larger than N. If M is larger than N, and 8826** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 8827** permitted to add content to the in-memory database as long as the total 8828** size does not exceed M bytes. 8829** 8830** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 8831** invoke sqlite3_free() on the serialization buffer when the database 8832** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 8833** SQLite will try to increase the buffer size using sqlite3_realloc64() 8834** if writes on the database cause it to grow larger than M bytes. 8835** 8836** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 8837** database is currently in a read transaction or is involved in a backup 8838** operation. 8839** 8840** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 8841** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 8842** [sqlite3_free()] is invoked on argument P prior to returning. 8843** 8844** This interface is only available if SQLite is compiled with the 8845** [SQLITE_ENABLE_DESERIALIZE] option. 8846*/ 8847int sqlite3_deserialize( 8848 sqlite3 *db, /* The database connection */ 8849 const char *zSchema, /* Which DB to reopen with the deserialization */ 8850 unsigned char *pData, /* The serialized database content */ 8851 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 8852 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 8853 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 8854); 8855 8856/* 8857** CAPI3REF: Flags for sqlite3_deserialize() 8858** 8859** The following are allowed values for 6th argument (the F argument) to 8860** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 8861** 8862** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 8863** in the P argument is held in memory obtained from [sqlite3_malloc64()] 8864** and that SQLite should take ownership of this memory and automatically 8865** free it when it has finished using it. Without this flag, the caller 8866** is resposible for freeing any dynamically allocated memory. 8867** 8868** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 8869** grow the size of the database using calls to [sqlite3_realloc64()]. This 8870** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 8871** Without this flag, the deserialized database cannot increase in size beyond 8872** the number of bytes specified by the M parameter. 8873** 8874** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 8875** should be treated as read-only. 8876*/ 8877#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 8878#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 8879#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 8880 8881/* 8882** Undo the hack that converts floating point types to integer for 8883** builds on processors without floating point support. 8884*/ 8885#ifdef SQLITE_OMIT_FLOATING_POINT 8886# undef double 8887#endif 8888 8889#ifdef __cplusplus 8890} /* End of the 'extern "C"' block */ 8891#endif 8892#endif /* SQLITE3_H */ 8893