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_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 476#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 477#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 478#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 479#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 480#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 481#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 482#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 483#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 484#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 485#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 486#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 487#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 488#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 489#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 490#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 491#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 492#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 493#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 494#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 495#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 496#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 497#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 498#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 499#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 500#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 501#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 502#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 503#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 504#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 505#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 506#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 507#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 508#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 509#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 510#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 511#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 512#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 513#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 514#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 515#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 516#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 517#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 518#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 519#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 520#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 521#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 522#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 523#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 524#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 525#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 526#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 527#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 528#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 529#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 530#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 531#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 532#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 533#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 534#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 535#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 536#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 537#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 538#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 539#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 540 541/* 542** CAPI3REF: Flags For File Open Operations 543** 544** These bit values are intended for use in the 545** 3rd parameter to the [sqlite3_open_v2()] interface and 546** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 547*/ 548#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 549#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 550#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 551#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 552#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 553#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 554#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 555#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 556#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 557#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 558#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 559#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 560#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 561#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 562#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 563#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 564#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 565#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 566#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 567#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 568 569/* Reserved: 0x00F00000 */ 570 571/* 572** CAPI3REF: Device Characteristics 573** 574** The xDeviceCharacteristics method of the [sqlite3_io_methods] 575** object returns an integer which is a vector of these 576** bit values expressing I/O characteristics of the mass storage 577** device that holds the file that the [sqlite3_io_methods] 578** refers to. 579** 580** The SQLITE_IOCAP_ATOMIC property means that all writes of 581** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 582** mean that writes of blocks that are nnn bytes in size and 583** are aligned to an address which is an integer multiple of 584** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 585** that when data is appended to a file, the data is appended 586** first then the size of the file is extended, never the other 587** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 588** information is written to disk in the same order as calls 589** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 590** after reboot following a crash or power loss, the only bytes in a 591** file that were written at the application level might have changed 592** and that adjacent bytes, even bytes within the same sector are 593** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 594** flag indicates that a file cannot be deleted when open. The 595** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 596** read-only media and cannot be changed even by processes with 597** elevated privileges. 598** 599** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 600** filesystem supports doing multiple write operations atomically when those 601** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 602** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 603*/ 604#define SQLITE_IOCAP_ATOMIC 0x00000001 605#define SQLITE_IOCAP_ATOMIC512 0x00000002 606#define SQLITE_IOCAP_ATOMIC1K 0x00000004 607#define SQLITE_IOCAP_ATOMIC2K 0x00000008 608#define SQLITE_IOCAP_ATOMIC4K 0x00000010 609#define SQLITE_IOCAP_ATOMIC8K 0x00000020 610#define SQLITE_IOCAP_ATOMIC16K 0x00000040 611#define SQLITE_IOCAP_ATOMIC32K 0x00000080 612#define SQLITE_IOCAP_ATOMIC64K 0x00000100 613#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 614#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 615#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 616#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 617#define SQLITE_IOCAP_IMMUTABLE 0x00002000 618#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 619 620/* 621** CAPI3REF: File Locking Levels 622** 623** SQLite uses one of these integer values as the second 624** argument to calls it makes to the xLock() and xUnlock() methods 625** of an [sqlite3_io_methods] object. 626*/ 627#define SQLITE_LOCK_NONE 0 628#define SQLITE_LOCK_SHARED 1 629#define SQLITE_LOCK_RESERVED 2 630#define SQLITE_LOCK_PENDING 3 631#define SQLITE_LOCK_EXCLUSIVE 4 632 633/* 634** CAPI3REF: Synchronization Type Flags 635** 636** When SQLite invokes the xSync() method of an 637** [sqlite3_io_methods] object it uses a combination of 638** these integer values as the second argument. 639** 640** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 641** sync operation only needs to flush data to mass storage. Inode 642** information need not be flushed. If the lower four bits of the flag 643** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 644** If the lower four bits equal SQLITE_SYNC_FULL, that means 645** to use Mac OS X style fullsync instead of fsync(). 646** 647** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 648** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 649** settings. The [synchronous pragma] determines when calls to the 650** xSync VFS method occur and applies uniformly across all platforms. 651** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 652** energetic or rigorous or forceful the sync operations are and 653** only make a difference on Mac OSX for the default SQLite code. 654** (Third-party VFS implementations might also make the distinction 655** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 656** operating systems natively supported by SQLite, only Mac OSX 657** cares about the difference.) 658*/ 659#define SQLITE_SYNC_NORMAL 0x00002 660#define SQLITE_SYNC_FULL 0x00003 661#define SQLITE_SYNC_DATAONLY 0x00010 662 663/* 664** CAPI3REF: OS Interface Open File Handle 665** 666** An [sqlite3_file] object represents an open file in the 667** [sqlite3_vfs | OS interface layer]. Individual OS interface 668** implementations will 669** want to subclass this object by appending additional fields 670** for their own use. The pMethods entry is a pointer to an 671** [sqlite3_io_methods] object that defines methods for performing 672** I/O operations on the open file. 673*/ 674typedef struct sqlite3_file sqlite3_file; 675struct sqlite3_file { 676 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 677}; 678 679/* 680** CAPI3REF: OS Interface File Virtual Methods Object 681** 682** Every file opened by the [sqlite3_vfs.xOpen] method populates an 683** [sqlite3_file] object (or, more commonly, a subclass of the 684** [sqlite3_file] object) with a pointer to an instance of this object. 685** This object defines the methods used to perform various operations 686** against the open file represented by the [sqlite3_file] object. 687** 688** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 689** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 690** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 691** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 692** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 693** to NULL. 694** 695** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 696** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 697** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 698** flag may be ORed in to indicate that only the data of the file 699** and not its inode needs to be synced. 700** 701** The integer values to xLock() and xUnlock() are one of 702** <ul> 703** <li> [SQLITE_LOCK_NONE], 704** <li> [SQLITE_LOCK_SHARED], 705** <li> [SQLITE_LOCK_RESERVED], 706** <li> [SQLITE_LOCK_PENDING], or 707** <li> [SQLITE_LOCK_EXCLUSIVE]. 708** </ul> 709** xLock() increases the lock. xUnlock() decreases the lock. 710** The xCheckReservedLock() method checks whether any database connection, 711** either in this process or in some other process, is holding a RESERVED, 712** PENDING, or EXCLUSIVE lock on the file. It returns true 713** if such a lock exists and false otherwise. 714** 715** The xFileControl() method is a generic interface that allows custom 716** VFS implementations to directly control an open file using the 717** [sqlite3_file_control()] interface. The second "op" argument is an 718** integer opcode. The third argument is a generic pointer intended to 719** point to a structure that may contain arguments or space in which to 720** write return values. Potential uses for xFileControl() might be 721** functions to enable blocking locks with timeouts, to change the 722** locking strategy (for example to use dot-file locks), to inquire 723** about the status of a lock, or to break stale locks. The SQLite 724** core reserves all opcodes less than 100 for its own use. 725** A [file control opcodes | list of opcodes] less than 100 is available. 726** Applications that define a custom xFileControl method should use opcodes 727** greater than 100 to avoid conflicts. VFS implementations should 728** return [SQLITE_NOTFOUND] for file control opcodes that they do not 729** recognize. 730** 731** The xSectorSize() method returns the sector size of the 732** device that underlies the file. The sector size is the 733** minimum write that can be performed without disturbing 734** other bytes in the file. The xDeviceCharacteristics() 735** method returns a bit vector describing behaviors of the 736** underlying device: 737** 738** <ul> 739** <li> [SQLITE_IOCAP_ATOMIC] 740** <li> [SQLITE_IOCAP_ATOMIC512] 741** <li> [SQLITE_IOCAP_ATOMIC1K] 742** <li> [SQLITE_IOCAP_ATOMIC2K] 743** <li> [SQLITE_IOCAP_ATOMIC4K] 744** <li> [SQLITE_IOCAP_ATOMIC8K] 745** <li> [SQLITE_IOCAP_ATOMIC16K] 746** <li> [SQLITE_IOCAP_ATOMIC32K] 747** <li> [SQLITE_IOCAP_ATOMIC64K] 748** <li> [SQLITE_IOCAP_SAFE_APPEND] 749** <li> [SQLITE_IOCAP_SEQUENTIAL] 750** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 751** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 752** <li> [SQLITE_IOCAP_IMMUTABLE] 753** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 754** </ul> 755** 756** The SQLITE_IOCAP_ATOMIC property means that all writes of 757** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 758** mean that writes of blocks that are nnn bytes in size and 759** are aligned to an address which is an integer multiple of 760** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 761** that when data is appended to a file, the data is appended 762** first then the size of the file is extended, never the other 763** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 764** information is written to disk in the same order as calls 765** to xWrite(). 766** 767** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 768** in the unread portions of the buffer with zeros. A VFS that 769** fails to zero-fill short reads might seem to work. However, 770** failure to zero-fill short reads will eventually lead to 771** database corruption. 772*/ 773typedef struct sqlite3_io_methods sqlite3_io_methods; 774struct sqlite3_io_methods { 775 int iVersion; 776 int (*xClose)(sqlite3_file*); 777 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 778 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 779 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 780 int (*xSync)(sqlite3_file*, int flags); 781 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 782 int (*xLock)(sqlite3_file*, int); 783 int (*xUnlock)(sqlite3_file*, int); 784 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 785 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 786 int (*xSectorSize)(sqlite3_file*); 787 int (*xDeviceCharacteristics)(sqlite3_file*); 788 /* Methods above are valid for version 1 */ 789 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 790 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 791 void (*xShmBarrier)(sqlite3_file*); 792 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 793 /* Methods above are valid for version 2 */ 794 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 795 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 796 /* Methods above are valid for version 3 */ 797 /* Additional methods may be added in future releases */ 798}; 799 800/* 801** CAPI3REF: Standard File Control Opcodes 802** KEYWORDS: {file control opcodes} {file control opcode} 803** 804** These integer constants are opcodes for the xFileControl method 805** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 806** interface. 807** 808** <ul> 809** <li>[[SQLITE_FCNTL_LOCKSTATE]] 810** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 811** opcode causes the xFileControl method to write the current state of 812** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 813** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 814** into an integer that the pArg argument points to. This capability 815** is used during testing and is only available when the SQLITE_TEST 816** compile-time option is used. 817** 818** <li>[[SQLITE_FCNTL_SIZE_HINT]] 819** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 820** layer a hint of how large the database file will grow to be during the 821** current transaction. This hint is not guaranteed to be accurate but it 822** is often close. The underlying VFS might choose to preallocate database 823** file space based on this hint in order to help writes to the database 824** file run faster. 825** 826** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 827** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 828** implements [sqlite3_deserialize()] to set an upper bound on the size 829** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 830** If the integer pointed to is negative, then it is filled in with the 831** current limit. Otherwise the limit is set to the larger of the value 832** of the integer pointed to and the current database size. The integer 833** pointed to is set to the new limit. 834** 835** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 836** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 837** extends and truncates the database file in chunks of a size specified 838** by the user. The fourth argument to [sqlite3_file_control()] should 839** point to an integer (type int) containing the new chunk-size to use 840** for the nominated database. Allocating database file space in large 841** chunks (say 1MB at a time), may reduce file-system fragmentation and 842** improve performance on some systems. 843** 844** <li>[[SQLITE_FCNTL_FILE_POINTER]] 845** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 846** to the [sqlite3_file] object associated with a particular database 847** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 848** 849** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 850** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 851** to the [sqlite3_file] object associated with the journal file (either 852** the [rollback journal] or the [write-ahead log]) for a particular database 853** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 854** 855** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 856** No longer in use. 857** 858** <li>[[SQLITE_FCNTL_SYNC]] 859** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 860** sent to the VFS immediately before the xSync method is invoked on a 861** database file descriptor. Or, if the xSync method is not invoked 862** because the user has configured SQLite with 863** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 864** of the xSync method. In most cases, the pointer argument passed with 865** this file-control is NULL. However, if the database file is being synced 866** as part of a multi-database commit, the argument points to a nul-terminated 867** string containing the transactions master-journal file name. VFSes that 868** do not need this signal should silently ignore this opcode. Applications 869** should not call [sqlite3_file_control()] with this opcode as doing so may 870** disrupt the operation of the specialized VFSes that do require it. 871** 872** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 873** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 874** and sent to the VFS after a transaction has been committed immediately 875** but before the database is unlocked. VFSes that do not need this signal 876** should silently ignore this opcode. Applications should not call 877** [sqlite3_file_control()] with this opcode as doing so may disrupt the 878** operation of the specialized VFSes that do require it. 879** 880** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 881** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 882** retry counts and intervals for certain disk I/O operations for the 883** windows [VFS] in order to provide robustness in the presence of 884** anti-virus programs. By default, the windows VFS will retry file read, 885** file write, and file delete operations up to 10 times, with a delay 886** of 25 milliseconds before the first retry and with the delay increasing 887** by an additional 25 milliseconds with each subsequent retry. This 888** opcode allows these two values (10 retries and 25 milliseconds of delay) 889** to be adjusted. The values are changed for all database connections 890** within the same process. The argument is a pointer to an array of two 891** integers where the first integer is the new retry count and the second 892** integer is the delay. If either integer is negative, then the setting 893** is not changed but instead the prior value of that setting is written 894** into the array entry, allowing the current retry settings to be 895** interrogated. The zDbName parameter is ignored. 896** 897** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 898** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 899** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 900** write ahead log ([WAL file]) and shared memory 901** files used for transaction control 902** are automatically deleted when the latest connection to the database 903** closes. Setting persistent WAL mode causes those files to persist after 904** close. Persisting the files is useful when other processes that do not 905** have write permission on the directory containing the database file want 906** to read the database file, as the WAL and shared memory files must exist 907** in order for the database to be readable. The fourth parameter to 908** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 909** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 910** WAL mode. If the integer is -1, then it is overwritten with the current 911** WAL persistence setting. 912** 913** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 914** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 915** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 916** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 917** xDeviceCharacteristics methods. The fourth parameter to 918** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 919** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 920** mode. If the integer is -1, then it is overwritten with the current 921** zero-damage mode setting. 922** 923** <li>[[SQLITE_FCNTL_OVERWRITE]] 924** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 925** a write transaction to indicate that, unless it is rolled back for some 926** reason, the entire database file will be overwritten by the current 927** transaction. This is used by VACUUM operations. 928** 929** <li>[[SQLITE_FCNTL_VFSNAME]] 930** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 931** all [VFSes] in the VFS stack. The names are of all VFS shims and the 932** final bottom-level VFS are written into memory obtained from 933** [sqlite3_malloc()] and the result is stored in the char* variable 934** that the fourth parameter of [sqlite3_file_control()] points to. 935** The caller is responsible for freeing the memory when done. As with 936** all file-control actions, there is no guarantee that this will actually 937** do anything. Callers should initialize the char* variable to a NULL 938** pointer in case this file-control is not implemented. This file-control 939** is intended for diagnostic use only. 940** 941** <li>[[SQLITE_FCNTL_VFS_POINTER]] 942** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 943** [VFSes] currently in use. ^(The argument X in 944** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 945** of type "[sqlite3_vfs] **". This opcodes will set *X 946** to a pointer to the top-level VFS.)^ 947** ^When there are multiple VFS shims in the stack, this opcode finds the 948** upper-most shim only. 949** 950** <li>[[SQLITE_FCNTL_PRAGMA]] 951** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 952** file control is sent to the open [sqlite3_file] object corresponding 953** to the database file to which the pragma statement refers. ^The argument 954** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 955** pointers to strings (char**) in which the second element of the array 956** is the name of the pragma and the third element is the argument to the 957** pragma or NULL if the pragma has no argument. ^The handler for an 958** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 959** of the char** argument point to a string obtained from [sqlite3_mprintf()] 960** or the equivalent and that string will become the result of the pragma or 961** the error message if the pragma fails. ^If the 962** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 963** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 964** file control returns [SQLITE_OK], then the parser assumes that the 965** VFS has handled the PRAGMA itself and the parser generates a no-op 966** prepared statement if result string is NULL, or that returns a copy 967** of the result string if the string is non-NULL. 968** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 969** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 970** that the VFS encountered an error while handling the [PRAGMA] and the 971** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 972** file control occurs at the beginning of pragma statement analysis and so 973** it is able to override built-in [PRAGMA] statements. 974** 975** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 976** ^The [SQLITE_FCNTL_BUSYHANDLER] 977** file-control may be invoked by SQLite on the database file handle 978** shortly after it is opened in order to provide a custom VFS with access 979** to the connections busy-handler callback. The argument is of type (void **) 980** - an array of two (void *) values. The first (void *) actually points 981** to a function of type (int (*)(void *)). In order to invoke the connections 982** busy-handler, this function should be invoked with the second (void *) in 983** the array as the only argument. If it returns non-zero, then the operation 984** should be retried. If it returns zero, the custom VFS should abandon the 985** current operation. 986** 987** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 988** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 989** to have SQLite generate a 990** temporary filename using the same algorithm that is followed to generate 991** temporary filenames for TEMP tables and other internal uses. The 992** argument should be a char** which will be filled with the filename 993** written into memory obtained from [sqlite3_malloc()]. The caller should 994** invoke [sqlite3_free()] on the result to avoid a memory leak. 995** 996** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 997** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 998** maximum number of bytes that will be used for memory-mapped I/O. 999** The argument is a pointer to a value of type sqlite3_int64 that 1000** is an advisory maximum number of bytes in the file to memory map. The 1001** pointer is overwritten with the old value. The limit is not changed if 1002** the value originally pointed to is negative, and so the current limit 1003** can be queried by passing in a pointer to a negative number. This 1004** file-control is used internally to implement [PRAGMA mmap_size]. 1005** 1006** <li>[[SQLITE_FCNTL_TRACE]] 1007** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1008** to the VFS about what the higher layers of the SQLite stack are doing. 1009** This file control is used by some VFS activity tracing [shims]. 1010** The argument is a zero-terminated string. Higher layers in the 1011** SQLite stack may generate instances of this file control if 1012** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1013** 1014** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1015** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1016** pointer to an integer and it writes a boolean into that integer depending 1017** on whether or not the file has been renamed, moved, or deleted since it 1018** was first opened. 1019** 1020** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1021** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1022** underlying native file handle associated with a file handle. This file 1023** control interprets its argument as a pointer to a native file handle and 1024** writes the resulting value there. 1025** 1026** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1027** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1028** opcode causes the xFileControl method to swap the file handle with the one 1029** pointed to by the pArg argument. This capability is used during testing 1030** and only needs to be supported when SQLITE_TEST is defined. 1031** 1032** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1033** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1034** be advantageous to block on the next WAL lock if the lock is not immediately 1035** available. The WAL subsystem issues this signal during rare 1036** circumstances in order to fix a problem with priority inversion. 1037** Applications should <em>not</em> use this file-control. 1038** 1039** <li>[[SQLITE_FCNTL_ZIPVFS]] 1040** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1041** VFS should return SQLITE_NOTFOUND for this opcode. 1042** 1043** <li>[[SQLITE_FCNTL_RBU]] 1044** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1045** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1046** this opcode. 1047** 1048** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1049** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1050** the file descriptor is placed in "batch write mode", which 1051** means all subsequent write operations will be deferred and done 1052** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1053** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1054** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1055** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1056** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1057** no VFS interface calls on the same [sqlite3_file] file descriptor 1058** except for calls to the xWrite method and the xFileControl method 1059** with [SQLITE_FCNTL_SIZE_HINT]. 1060** 1061** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1062** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1063** operations since the previous successful call to 1064** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1065** This file control returns [SQLITE_OK] if and only if the writes were 1066** all performed successfully and have been committed to persistent storage. 1067** ^Regardless of whether or not it is successful, this file control takes 1068** the file descriptor out of batch write mode so that all subsequent 1069** write operations are independent. 1070** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1071** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1072** 1073** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1074** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1075** operations since the previous successful call to 1076** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1077** ^This file control takes the file descriptor out of batch write mode 1078** so that all subsequent write operations are independent. 1079** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1080** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1081** 1082** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1083** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain 1084** a file lock using the xLock or xShmLock methods of the VFS to wait 1085** for up to M milliseconds before failing, where M is the single 1086** unsigned integer parameter. 1087** 1088** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1089** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1090** a database file. The argument is a pointer to a 32-bit unsigned integer. 1091** The "data version" for the pager is written into the pointer. The 1092** "data version" changes whenever any change occurs to the corresponding 1093** database file, either through SQL statements on the same database 1094** connection or through transactions committed by separate database 1095** connections possibly in other processes. The [sqlite3_total_changes()] 1096** interface can be used to find if any database on the connection has changed, 1097** but that interface responds to changes on TEMP as well as MAIN and does 1098** not provide a mechanism to detect changes to MAIN only. Also, the 1099** [sqlite3_total_changes()] interface responds to internal changes only and 1100** omits changes made by other database connections. The 1101** [PRAGMA data_version] command provide a mechanism to detect changes to 1102** a single attached database that occur due to other database connections, 1103** but omits changes implemented by the database connection on which it is 1104** called. This file control is the only mechanism to detect changes that 1105** happen either internally or externally and that are associated with 1106** a particular attached database. 1107** </ul> 1108*/ 1109#define SQLITE_FCNTL_LOCKSTATE 1 1110#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1111#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1112#define SQLITE_FCNTL_LAST_ERRNO 4 1113#define SQLITE_FCNTL_SIZE_HINT 5 1114#define SQLITE_FCNTL_CHUNK_SIZE 6 1115#define SQLITE_FCNTL_FILE_POINTER 7 1116#define SQLITE_FCNTL_SYNC_OMITTED 8 1117#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1118#define SQLITE_FCNTL_PERSIST_WAL 10 1119#define SQLITE_FCNTL_OVERWRITE 11 1120#define SQLITE_FCNTL_VFSNAME 12 1121#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1122#define SQLITE_FCNTL_PRAGMA 14 1123#define SQLITE_FCNTL_BUSYHANDLER 15 1124#define SQLITE_FCNTL_TEMPFILENAME 16 1125#define SQLITE_FCNTL_MMAP_SIZE 18 1126#define SQLITE_FCNTL_TRACE 19 1127#define SQLITE_FCNTL_HAS_MOVED 20 1128#define SQLITE_FCNTL_SYNC 21 1129#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1130#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1131#define SQLITE_FCNTL_WAL_BLOCK 24 1132#define SQLITE_FCNTL_ZIPVFS 25 1133#define SQLITE_FCNTL_RBU 26 1134#define SQLITE_FCNTL_VFS_POINTER 27 1135#define SQLITE_FCNTL_JOURNAL_POINTER 28 1136#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1137#define SQLITE_FCNTL_PDB 30 1138#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1139#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1140#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1141#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1142#define SQLITE_FCNTL_DATA_VERSION 35 1143#define SQLITE_FCNTL_SIZE_LIMIT 36 1144 1145/* deprecated names */ 1146#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1147#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1148#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1149 1150 1151/* 1152** CAPI3REF: Mutex Handle 1153** 1154** The mutex module within SQLite defines [sqlite3_mutex] to be an 1155** abstract type for a mutex object. The SQLite core never looks 1156** at the internal representation of an [sqlite3_mutex]. It only 1157** deals with pointers to the [sqlite3_mutex] object. 1158** 1159** Mutexes are created using [sqlite3_mutex_alloc()]. 1160*/ 1161typedef struct sqlite3_mutex sqlite3_mutex; 1162 1163/* 1164** CAPI3REF: Loadable Extension Thunk 1165** 1166** A pointer to the opaque sqlite3_api_routines structure is passed as 1167** the third parameter to entry points of [loadable extensions]. This 1168** structure must be typedefed in order to work around compiler warnings 1169** on some platforms. 1170*/ 1171typedef struct sqlite3_api_routines sqlite3_api_routines; 1172 1173/* 1174** CAPI3REF: OS Interface Object 1175** 1176** An instance of the sqlite3_vfs object defines the interface between 1177** the SQLite core and the underlying operating system. The "vfs" 1178** in the name of the object stands for "virtual file system". See 1179** the [VFS | VFS documentation] for further information. 1180** 1181** The VFS interface is sometimes extended by adding new methods onto 1182** the end. Each time such an extension occurs, the iVersion field 1183** is incremented. The iVersion value started out as 1 in 1184** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1185** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1186** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1187** may be appended to the sqlite3_vfs object and the iVersion value 1188** may increase again in future versions of SQLite. 1189** Note that the structure 1190** of the sqlite3_vfs object changes in the transition from 1191** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1192** and yet the iVersion field was not modified. 1193** 1194** The szOsFile field is the size of the subclassed [sqlite3_file] 1195** structure used by this VFS. mxPathname is the maximum length of 1196** a pathname in this VFS. 1197** 1198** Registered sqlite3_vfs objects are kept on a linked list formed by 1199** the pNext pointer. The [sqlite3_vfs_register()] 1200** and [sqlite3_vfs_unregister()] interfaces manage this list 1201** in a thread-safe way. The [sqlite3_vfs_find()] interface 1202** searches the list. Neither the application code nor the VFS 1203** implementation should use the pNext pointer. 1204** 1205** The pNext field is the only field in the sqlite3_vfs 1206** structure that SQLite will ever modify. SQLite will only access 1207** or modify this field while holding a particular static mutex. 1208** The application should never modify anything within the sqlite3_vfs 1209** object once the object has been registered. 1210** 1211** The zName field holds the name of the VFS module. The name must 1212** be unique across all VFS modules. 1213** 1214** [[sqlite3_vfs.xOpen]] 1215** ^SQLite guarantees that the zFilename parameter to xOpen 1216** is either a NULL pointer or string obtained 1217** from xFullPathname() with an optional suffix added. 1218** ^If a suffix is added to the zFilename parameter, it will 1219** consist of a single "-" character followed by no more than 1220** 11 alphanumeric and/or "-" characters. 1221** ^SQLite further guarantees that 1222** the string will be valid and unchanged until xClose() is 1223** called. Because of the previous sentence, 1224** the [sqlite3_file] can safely store a pointer to the 1225** filename if it needs to remember the filename for some reason. 1226** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1227** must invent its own temporary name for the file. ^Whenever the 1228** xFilename parameter is NULL it will also be the case that the 1229** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1230** 1231** The flags argument to xOpen() includes all bits set in 1232** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1233** or [sqlite3_open16()] is used, then flags includes at least 1234** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1235** If xOpen() opens a file read-only then it sets *pOutFlags to 1236** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1237** 1238** ^(SQLite will also add one of the following flags to the xOpen() 1239** call, depending on the object being opened: 1240** 1241** <ul> 1242** <li> [SQLITE_OPEN_MAIN_DB] 1243** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1244** <li> [SQLITE_OPEN_TEMP_DB] 1245** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1246** <li> [SQLITE_OPEN_TRANSIENT_DB] 1247** <li> [SQLITE_OPEN_SUBJOURNAL] 1248** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1249** <li> [SQLITE_OPEN_WAL] 1250** </ul>)^ 1251** 1252** The file I/O implementation can use the object type flags to 1253** change the way it deals with files. For example, an application 1254** that does not care about crash recovery or rollback might make 1255** the open of a journal file a no-op. Writes to this journal would 1256** also be no-ops, and any attempt to read the journal would return 1257** SQLITE_IOERR. Or the implementation might recognize that a database 1258** file will be doing page-aligned sector reads and writes in a random 1259** order and set up its I/O subsystem accordingly. 1260** 1261** SQLite might also add one of the following flags to the xOpen method: 1262** 1263** <ul> 1264** <li> [SQLITE_OPEN_DELETEONCLOSE] 1265** <li> [SQLITE_OPEN_EXCLUSIVE] 1266** </ul> 1267** 1268** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1269** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1270** will be set for TEMP databases and their journals, transient 1271** databases, and subjournals. 1272** 1273** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1274** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1275** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1276** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1277** SQLITE_OPEN_CREATE, is used to indicate that file should always 1278** be created, and that it is an error if it already exists. 1279** It is <i>not</i> used to indicate the file should be opened 1280** for exclusive access. 1281** 1282** ^At least szOsFile bytes of memory are allocated by SQLite 1283** to hold the [sqlite3_file] structure passed as the third 1284** argument to xOpen. The xOpen method does not have to 1285** allocate the structure; it should just fill it in. Note that 1286** the xOpen method must set the sqlite3_file.pMethods to either 1287** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1288** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1289** element will be valid after xOpen returns regardless of the success 1290** or failure of the xOpen call. 1291** 1292** [[sqlite3_vfs.xAccess]] 1293** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1294** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1295** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1296** to test whether a file is at least readable. The file can be a 1297** directory. 1298** 1299** ^SQLite will always allocate at least mxPathname+1 bytes for the 1300** output buffer xFullPathname. The exact size of the output buffer 1301** is also passed as a parameter to both methods. If the output buffer 1302** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1303** handled as a fatal error by SQLite, vfs implementations should endeavor 1304** to prevent this by setting mxPathname to a sufficiently large value. 1305** 1306** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1307** interfaces are not strictly a part of the filesystem, but they are 1308** included in the VFS structure for completeness. 1309** The xRandomness() function attempts to return nBytes bytes 1310** of good-quality randomness into zOut. The return value is 1311** the actual number of bytes of randomness obtained. 1312** The xSleep() method causes the calling thread to sleep for at 1313** least the number of microseconds given. ^The xCurrentTime() 1314** method returns a Julian Day Number for the current date and time as 1315** a floating point value. 1316** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1317** Day Number multiplied by 86400000 (the number of milliseconds in 1318** a 24-hour day). 1319** ^SQLite will use the xCurrentTimeInt64() method to get the current 1320** date and time if that method is available (if iVersion is 2 or 1321** greater and the function pointer is not NULL) and will fall back 1322** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1323** 1324** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1325** are not used by the SQLite core. These optional interfaces are provided 1326** by some VFSes to facilitate testing of the VFS code. By overriding 1327** system calls with functions under its control, a test program can 1328** simulate faults and error conditions that would otherwise be difficult 1329** or impossible to induce. The set of system calls that can be overridden 1330** varies from one VFS to another, and from one version of the same VFS to the 1331** next. Applications that use these interfaces must be prepared for any 1332** or all of these interfaces to be NULL or for their behavior to change 1333** from one release to the next. Applications must not attempt to access 1334** any of these methods if the iVersion of the VFS is less than 3. 1335*/ 1336typedef struct sqlite3_vfs sqlite3_vfs; 1337typedef void (*sqlite3_syscall_ptr)(void); 1338struct sqlite3_vfs { 1339 int iVersion; /* Structure version number (currently 3) */ 1340 int szOsFile; /* Size of subclassed sqlite3_file */ 1341 int mxPathname; /* Maximum file pathname length */ 1342 sqlite3_vfs *pNext; /* Next registered VFS */ 1343 const char *zName; /* Name of this virtual file system */ 1344 void *pAppData; /* Pointer to application-specific data */ 1345 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1346 int flags, int *pOutFlags); 1347 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1348 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1349 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1350 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1351 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1352 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1353 void (*xDlClose)(sqlite3_vfs*, void*); 1354 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1355 int (*xSleep)(sqlite3_vfs*, int microseconds); 1356 int (*xCurrentTime)(sqlite3_vfs*, double*); 1357 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1358 /* 1359 ** The methods above are in version 1 of the sqlite_vfs object 1360 ** definition. Those that follow are added in version 2 or later 1361 */ 1362 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1363 /* 1364 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1365 ** Those below are for version 3 and greater. 1366 */ 1367 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1368 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1369 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1370 /* 1371 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1372 ** New fields may be appended in future versions. The iVersion 1373 ** value will increment whenever this happens. 1374 */ 1375}; 1376 1377/* 1378** CAPI3REF: Flags for the xAccess VFS method 1379** 1380** These integer constants can be used as the third parameter to 1381** the xAccess method of an [sqlite3_vfs] object. They determine 1382** what kind of permissions the xAccess method is looking for. 1383** With SQLITE_ACCESS_EXISTS, the xAccess method 1384** simply checks whether the file exists. 1385** With SQLITE_ACCESS_READWRITE, the xAccess method 1386** checks whether the named directory is both readable and writable 1387** (in other words, if files can be added, removed, and renamed within 1388** the directory). 1389** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1390** [temp_store_directory pragma], though this could change in a future 1391** release of SQLite. 1392** With SQLITE_ACCESS_READ, the xAccess method 1393** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1394** currently unused, though it might be used in a future release of 1395** SQLite. 1396*/ 1397#define SQLITE_ACCESS_EXISTS 0 1398#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1399#define SQLITE_ACCESS_READ 2 /* Unused */ 1400 1401/* 1402** CAPI3REF: Flags for the xShmLock VFS method 1403** 1404** These integer constants define the various locking operations 1405** allowed by the xShmLock method of [sqlite3_io_methods]. The 1406** following are the only legal combinations of flags to the 1407** xShmLock method: 1408** 1409** <ul> 1410** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1411** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1412** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1413** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1414** </ul> 1415** 1416** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1417** was given on the corresponding lock. 1418** 1419** The xShmLock method can transition between unlocked and SHARED or 1420** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1421** and EXCLUSIVE. 1422*/ 1423#define SQLITE_SHM_UNLOCK 1 1424#define SQLITE_SHM_LOCK 2 1425#define SQLITE_SHM_SHARED 4 1426#define SQLITE_SHM_EXCLUSIVE 8 1427 1428/* 1429** CAPI3REF: Maximum xShmLock index 1430** 1431** The xShmLock method on [sqlite3_io_methods] may use values 1432** between 0 and this upper bound as its "offset" argument. 1433** The SQLite core will never attempt to acquire or release a 1434** lock outside of this range 1435*/ 1436#define SQLITE_SHM_NLOCK 8 1437 1438 1439/* 1440** CAPI3REF: Initialize The SQLite Library 1441** 1442** ^The sqlite3_initialize() routine initializes the 1443** SQLite library. ^The sqlite3_shutdown() routine 1444** deallocates any resources that were allocated by sqlite3_initialize(). 1445** These routines are designed to aid in process initialization and 1446** shutdown on embedded systems. Workstation applications using 1447** SQLite normally do not need to invoke either of these routines. 1448** 1449** A call to sqlite3_initialize() is an "effective" call if it is 1450** the first time sqlite3_initialize() is invoked during the lifetime of 1451** the process, or if it is the first time sqlite3_initialize() is invoked 1452** following a call to sqlite3_shutdown(). ^(Only an effective call 1453** of sqlite3_initialize() does any initialization. All other calls 1454** are harmless no-ops.)^ 1455** 1456** A call to sqlite3_shutdown() is an "effective" call if it is the first 1457** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1458** an effective call to sqlite3_shutdown() does any deinitialization. 1459** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1460** 1461** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1462** is not. The sqlite3_shutdown() interface must only be called from a 1463** single thread. All open [database connections] must be closed and all 1464** other SQLite resources must be deallocated prior to invoking 1465** sqlite3_shutdown(). 1466** 1467** Among other things, ^sqlite3_initialize() will invoke 1468** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1469** will invoke sqlite3_os_end(). 1470** 1471** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1472** ^If for some reason, sqlite3_initialize() is unable to initialize 1473** the library (perhaps it is unable to allocate a needed resource such 1474** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1475** 1476** ^The sqlite3_initialize() routine is called internally by many other 1477** SQLite interfaces so that an application usually does not need to 1478** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1479** calls sqlite3_initialize() so the SQLite library will be automatically 1480** initialized when [sqlite3_open()] is called if it has not be initialized 1481** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1482** compile-time option, then the automatic calls to sqlite3_initialize() 1483** are omitted and the application must call sqlite3_initialize() directly 1484** prior to using any other SQLite interface. For maximum portability, 1485** it is recommended that applications always invoke sqlite3_initialize() 1486** directly prior to using any other SQLite interface. Future releases 1487** of SQLite may require this. In other words, the behavior exhibited 1488** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1489** default behavior in some future release of SQLite. 1490** 1491** The sqlite3_os_init() routine does operating-system specific 1492** initialization of the SQLite library. The sqlite3_os_end() 1493** routine undoes the effect of sqlite3_os_init(). Typical tasks 1494** performed by these routines include allocation or deallocation 1495** of static resources, initialization of global variables, 1496** setting up a default [sqlite3_vfs] module, or setting up 1497** a default configuration using [sqlite3_config()]. 1498** 1499** The application should never invoke either sqlite3_os_init() 1500** or sqlite3_os_end() directly. The application should only invoke 1501** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1502** interface is called automatically by sqlite3_initialize() and 1503** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1504** implementations for sqlite3_os_init() and sqlite3_os_end() 1505** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1506** When [custom builds | built for other platforms] 1507** (using the [SQLITE_OS_OTHER=1] compile-time 1508** option) the application must supply a suitable implementation for 1509** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1510** implementation of sqlite3_os_init() or sqlite3_os_end() 1511** must return [SQLITE_OK] on success and some other [error code] upon 1512** failure. 1513*/ 1514int sqlite3_initialize(void); 1515int sqlite3_shutdown(void); 1516int sqlite3_os_init(void); 1517int sqlite3_os_end(void); 1518 1519/* 1520** CAPI3REF: Configuring The SQLite Library 1521** 1522** The sqlite3_config() interface is used to make global configuration 1523** changes to SQLite in order to tune SQLite to the specific needs of 1524** the application. The default configuration is recommended for most 1525** applications and so this routine is usually not necessary. It is 1526** provided to support rare applications with unusual needs. 1527** 1528** <b>The sqlite3_config() interface is not threadsafe. The application 1529** must ensure that no other SQLite interfaces are invoked by other 1530** threads while sqlite3_config() is running.</b> 1531** 1532** The sqlite3_config() interface 1533** may only be invoked prior to library initialization using 1534** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1535** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1536** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1537** Note, however, that ^sqlite3_config() can be called as part of the 1538** implementation of an application-defined [sqlite3_os_init()]. 1539** 1540** The first argument to sqlite3_config() is an integer 1541** [configuration option] that determines 1542** what property of SQLite is to be configured. Subsequent arguments 1543** vary depending on the [configuration option] 1544** in the first argument. 1545** 1546** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1547** ^If the option is unknown or SQLite is unable to set the option 1548** then this routine returns a non-zero [error code]. 1549*/ 1550int sqlite3_config(int, ...); 1551 1552/* 1553** CAPI3REF: Configure database connections 1554** METHOD: sqlite3 1555** 1556** The sqlite3_db_config() interface is used to make configuration 1557** changes to a [database connection]. The interface is similar to 1558** [sqlite3_config()] except that the changes apply to a single 1559** [database connection] (specified in the first argument). 1560** 1561** The second argument to sqlite3_db_config(D,V,...) is the 1562** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1563** that indicates what aspect of the [database connection] is being configured. 1564** Subsequent arguments vary depending on the configuration verb. 1565** 1566** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1567** the call is considered successful. 1568*/ 1569int sqlite3_db_config(sqlite3*, int op, ...); 1570 1571/* 1572** CAPI3REF: Memory Allocation Routines 1573** 1574** An instance of this object defines the interface between SQLite 1575** and low-level memory allocation routines. 1576** 1577** This object is used in only one place in the SQLite interface. 1578** A pointer to an instance of this object is the argument to 1579** [sqlite3_config()] when the configuration option is 1580** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1581** By creating an instance of this object 1582** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1583** during configuration, an application can specify an alternative 1584** memory allocation subsystem for SQLite to use for all of its 1585** dynamic memory needs. 1586** 1587** Note that SQLite comes with several [built-in memory allocators] 1588** that are perfectly adequate for the overwhelming majority of applications 1589** and that this object is only useful to a tiny minority of applications 1590** with specialized memory allocation requirements. This object is 1591** also used during testing of SQLite in order to specify an alternative 1592** memory allocator that simulates memory out-of-memory conditions in 1593** order to verify that SQLite recovers gracefully from such 1594** conditions. 1595** 1596** The xMalloc, xRealloc, and xFree methods must work like the 1597** malloc(), realloc() and free() functions from the standard C library. 1598** ^SQLite guarantees that the second argument to 1599** xRealloc is always a value returned by a prior call to xRoundup. 1600** 1601** xSize should return the allocated size of a memory allocation 1602** previously obtained from xMalloc or xRealloc. The allocated size 1603** is always at least as big as the requested size but may be larger. 1604** 1605** The xRoundup method returns what would be the allocated size of 1606** a memory allocation given a particular requested size. Most memory 1607** allocators round up memory allocations at least to the next multiple 1608** of 8. Some allocators round up to a larger multiple or to a power of 2. 1609** Every memory allocation request coming in through [sqlite3_malloc()] 1610** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1611** that causes the corresponding memory allocation to fail. 1612** 1613** The xInit method initializes the memory allocator. For example, 1614** it might allocate any require mutexes or initialize internal data 1615** structures. The xShutdown method is invoked (indirectly) by 1616** [sqlite3_shutdown()] and should deallocate any resources acquired 1617** by xInit. The pAppData pointer is used as the only parameter to 1618** xInit and xShutdown. 1619** 1620** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1621** the xInit method, so the xInit method need not be threadsafe. The 1622** xShutdown method is only called from [sqlite3_shutdown()] so it does 1623** not need to be threadsafe either. For all other methods, SQLite 1624** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1625** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1626** it is by default) and so the methods are automatically serialized. 1627** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1628** methods must be threadsafe or else make their own arrangements for 1629** serialization. 1630** 1631** SQLite will never invoke xInit() more than once without an intervening 1632** call to xShutdown(). 1633*/ 1634typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1635struct sqlite3_mem_methods { 1636 void *(*xMalloc)(int); /* Memory allocation function */ 1637 void (*xFree)(void*); /* Free a prior allocation */ 1638 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1639 int (*xSize)(void*); /* Return the size of an allocation */ 1640 int (*xRoundup)(int); /* Round up request size to allocation size */ 1641 int (*xInit)(void*); /* Initialize the memory allocator */ 1642 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1643 void *pAppData; /* Argument to xInit() and xShutdown() */ 1644}; 1645 1646/* 1647** CAPI3REF: Configuration Options 1648** KEYWORDS: {configuration option} 1649** 1650** These constants are the available integer configuration options that 1651** can be passed as the first argument to the [sqlite3_config()] interface. 1652** 1653** New configuration options may be added in future releases of SQLite. 1654** Existing configuration options might be discontinued. Applications 1655** should check the return code from [sqlite3_config()] to make sure that 1656** the call worked. The [sqlite3_config()] interface will return a 1657** non-zero [error code] if a discontinued or unsupported configuration option 1658** is invoked. 1659** 1660** <dl> 1661** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1662** <dd>There are no arguments to this option. ^This option sets the 1663** [threading mode] to Single-thread. In other words, it disables 1664** all mutexing and puts SQLite into a mode where it can only be used 1665** by a single thread. ^If SQLite is compiled with 1666** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1667** it is not possible to change the [threading mode] from its default 1668** value of Single-thread and so [sqlite3_config()] will return 1669** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1670** configuration option.</dd> 1671** 1672** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1673** <dd>There are no arguments to this option. ^This option sets the 1674** [threading mode] to Multi-thread. In other words, it disables 1675** mutexing on [database connection] and [prepared statement] objects. 1676** The application is responsible for serializing access to 1677** [database connections] and [prepared statements]. But other mutexes 1678** are enabled so that SQLite will be safe to use in a multi-threaded 1679** environment as long as no two threads attempt to use the same 1680** [database connection] at the same time. ^If SQLite is compiled with 1681** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1682** it is not possible to set the Multi-thread [threading mode] and 1683** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1684** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1685** 1686** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1687** <dd>There are no arguments to this option. ^This option sets the 1688** [threading mode] to Serialized. In other words, this option enables 1689** all mutexes including the recursive 1690** mutexes on [database connection] and [prepared statement] objects. 1691** In this mode (which is the default when SQLite is compiled with 1692** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1693** to [database connections] and [prepared statements] so that the 1694** application is free to use the same [database connection] or the 1695** same [prepared statement] in different threads at the same time. 1696** ^If SQLite is compiled with 1697** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1698** it is not possible to set the Serialized [threading mode] and 1699** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1700** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1701** 1702** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1703** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1704** a pointer to an instance of the [sqlite3_mem_methods] structure. 1705** The argument specifies 1706** alternative low-level memory allocation routines to be used in place of 1707** the memory allocation routines built into SQLite.)^ ^SQLite makes 1708** its own private copy of the content of the [sqlite3_mem_methods] structure 1709** before the [sqlite3_config()] call returns.</dd> 1710** 1711** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1712** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1713** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1714** The [sqlite3_mem_methods] 1715** structure is filled with the currently defined memory allocation routines.)^ 1716** This option can be used to overload the default memory allocation 1717** routines with a wrapper that simulations memory allocation failure or 1718** tracks memory usage, for example. </dd> 1719** 1720** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1721** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1722** type int, interpreted as a boolean, which if true provides a hint to 1723** SQLite that it should avoid large memory allocations if possible. 1724** SQLite will run faster if it is free to make large memory allocations, 1725** but some application might prefer to run slower in exchange for 1726** guarantees about memory fragmentation that are possible if large 1727** allocations are avoided. This hint is normally off. 1728** </dd> 1729** 1730** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1731** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1732** interpreted as a boolean, which enables or disables the collection of 1733** memory allocation statistics. ^(When memory allocation statistics are 1734** disabled, the following SQLite interfaces become non-operational: 1735** <ul> 1736** <li> [sqlite3_memory_used()] 1737** <li> [sqlite3_memory_highwater()] 1738** <li> [sqlite3_soft_heap_limit64()] 1739** <li> [sqlite3_status64()] 1740** </ul>)^ 1741** ^Memory allocation statistics are enabled by default unless SQLite is 1742** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1743** allocation statistics are disabled by default. 1744** </dd> 1745** 1746** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1747** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1748** </dd> 1749** 1750** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1751** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1752** that SQLite can use for the database page cache with the default page 1753** cache implementation. 1754** This configuration option is a no-op if an application-define page 1755** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1756** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1757** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1758** and the number of cache lines (N). 1759** The sz argument should be the size of the largest database page 1760** (a power of two between 512 and 65536) plus some extra bytes for each 1761** page header. ^The number of extra bytes needed by the page header 1762** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1763** ^It is harmless, apart from the wasted memory, 1764** for the sz parameter to be larger than necessary. The pMem 1765** argument must be either a NULL pointer or a pointer to an 8-byte 1766** aligned block of memory of at least sz*N bytes, otherwise 1767** subsequent behavior is undefined. 1768** ^When pMem is not NULL, SQLite will strive to use the memory provided 1769** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1770** a page cache line is larger than sz bytes or if all of the pMem buffer 1771** is exhausted. 1772** ^If pMem is NULL and N is non-zero, then each database connection 1773** does an initial bulk allocation for page cache memory 1774** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1775** of -1024*N bytes if N is negative, . ^If additional 1776** page cache memory is needed beyond what is provided by the initial 1777** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1778** additional cache line. </dd> 1779** 1780** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1781** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1782** that SQLite will use for all of its dynamic memory allocation needs 1783** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1784** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1785** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1786** [SQLITE_ERROR] if invoked otherwise. 1787** ^There are three arguments to SQLITE_CONFIG_HEAP: 1788** An 8-byte aligned pointer to the memory, 1789** the number of bytes in the memory buffer, and the minimum allocation size. 1790** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1791** to using its default memory allocator (the system malloc() implementation), 1792** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1793** memory pointer is not NULL then the alternative memory 1794** allocator is engaged to handle all of SQLites memory allocation needs. 1795** The first pointer (the memory pointer) must be aligned to an 8-byte 1796** boundary or subsequent behavior of SQLite will be undefined. 1797** The minimum allocation size is capped at 2**12. Reasonable values 1798** for the minimum allocation size are 2**5 through 2**8.</dd> 1799** 1800** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1801** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1802** pointer to an instance of the [sqlite3_mutex_methods] structure. 1803** The argument specifies alternative low-level mutex routines to be used 1804** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1805** the content of the [sqlite3_mutex_methods] structure before the call to 1806** [sqlite3_config()] returns. ^If SQLite is compiled with 1807** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1808** the entire mutexing subsystem is omitted from the build and hence calls to 1809** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1810** return [SQLITE_ERROR].</dd> 1811** 1812** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1813** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1814** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1815** [sqlite3_mutex_methods] 1816** structure is filled with the currently defined mutex routines.)^ 1817** This option can be used to overload the default mutex allocation 1818** routines with a wrapper used to track mutex usage for performance 1819** profiling or testing, for example. ^If SQLite is compiled with 1820** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1821** the entire mutexing subsystem is omitted from the build and hence calls to 1822** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1823** return [SQLITE_ERROR].</dd> 1824** 1825** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1826** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1827** the default size of lookaside memory on each [database connection]. 1828** The first argument is the 1829** size of each lookaside buffer slot and the second is the number of 1830** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1831** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1832** option to [sqlite3_db_config()] can be used to change the lookaside 1833** configuration on individual connections.)^ </dd> 1834** 1835** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1836** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1837** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1838** the interface to a custom page cache implementation.)^ 1839** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1840** 1841** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1842** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1843** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1844** the current page cache implementation into that object.)^ </dd> 1845** 1846** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1847** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1848** global [error log]. 1849** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1850** function with a call signature of void(*)(void*,int,const char*), 1851** and a pointer to void. ^If the function pointer is not NULL, it is 1852** invoked by [sqlite3_log()] to process each logging event. ^If the 1853** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1854** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1855** passed through as the first parameter to the application-defined logger 1856** function whenever that function is invoked. ^The second parameter to 1857** the logger function is a copy of the first parameter to the corresponding 1858** [sqlite3_log()] call and is intended to be a [result code] or an 1859** [extended result code]. ^The third parameter passed to the logger is 1860** log message after formatting via [sqlite3_snprintf()]. 1861** The SQLite logging interface is not reentrant; the logger function 1862** supplied by the application must not invoke any SQLite interface. 1863** In a multi-threaded application, the application-defined logger 1864** function must be threadsafe. </dd> 1865** 1866** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1867** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1868** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1869** then URI handling is globally disabled.)^ ^If URI handling is globally 1870** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1871** [sqlite3_open16()] or 1872** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1873** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1874** connection is opened. ^If it is globally disabled, filenames are 1875** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1876** database connection is opened. ^(By default, URI handling is globally 1877** disabled. The default value may be changed by compiling with the 1878** [SQLITE_USE_URI] symbol defined.)^ 1879** 1880** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1881** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1882** argument which is interpreted as a boolean in order to enable or disable 1883** the use of covering indices for full table scans in the query optimizer. 1884** ^The default setting is determined 1885** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1886** if that compile-time option is omitted. 1887** The ability to disable the use of covering indices for full table scans 1888** is because some incorrectly coded legacy applications might malfunction 1889** when the optimization is enabled. Providing the ability to 1890** disable the optimization allows the older, buggy application code to work 1891** without change even with newer versions of SQLite. 1892** 1893** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1894** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1895** <dd> These options are obsolete and should not be used by new code. 1896** They are retained for backwards compatibility but are now no-ops. 1897** </dd> 1898** 1899** [[SQLITE_CONFIG_SQLLOG]] 1900** <dt>SQLITE_CONFIG_SQLLOG 1901** <dd>This option is only available if sqlite is compiled with the 1902** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1903** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1904** The second should be of type (void*). The callback is invoked by the library 1905** in three separate circumstances, identified by the value passed as the 1906** fourth parameter. If the fourth parameter is 0, then the database connection 1907** passed as the second argument has just been opened. The third argument 1908** points to a buffer containing the name of the main database file. If the 1909** fourth parameter is 1, then the SQL statement that the third parameter 1910** points to has just been executed. Or, if the fourth parameter is 2, then 1911** the connection being passed as the second parameter is being closed. The 1912** third parameter is passed NULL In this case. An example of using this 1913** configuration option can be seen in the "test_sqllog.c" source file in 1914** the canonical SQLite source tree.</dd> 1915** 1916** [[SQLITE_CONFIG_MMAP_SIZE]] 1917** <dt>SQLITE_CONFIG_MMAP_SIZE 1918** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1919** that are the default mmap size limit (the default setting for 1920** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1921** ^The default setting can be overridden by each database connection using 1922** either the [PRAGMA mmap_size] command, or by using the 1923** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1924** will be silently truncated if necessary so that it does not exceed the 1925** compile-time maximum mmap size set by the 1926** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1927** ^If either argument to this option is negative, then that argument is 1928** changed to its compile-time default. 1929** 1930** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1931** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1932** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1933** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1934** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1935** that specifies the maximum size of the created heap. 1936** 1937** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1938** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1939** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1940** is a pointer to an integer and writes into that integer the number of extra 1941** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1942** The amount of extra space required can change depending on the compiler, 1943** target platform, and SQLite version. 1944** 1945** [[SQLITE_CONFIG_PMASZ]] 1946** <dt>SQLITE_CONFIG_PMASZ 1947** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1948** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1949** sorter to that integer. The default minimum PMA Size is set by the 1950** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1951** to help with sort operations when multithreaded sorting 1952** is enabled (using the [PRAGMA threads] command) and the amount of content 1953** to be sorted exceeds the page size times the minimum of the 1954** [PRAGMA cache_size] setting and this value. 1955** 1956** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1957** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1958** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1959** becomes the [statement journal] spill-to-disk threshold. 1960** [Statement journals] are held in memory until their size (in bytes) 1961** exceeds this threshold, at which point they are written to disk. 1962** Or if the threshold is -1, statement journals are always held 1963** exclusively in memory. 1964** Since many statement journals never become large, setting the spill 1965** threshold to a value such as 64KiB can greatly reduce the amount of 1966** I/O required to support statement rollback. 1967** The default value for this setting is controlled by the 1968** [SQLITE_STMTJRNL_SPILL] compile-time option. 1969** 1970** [[SQLITE_CONFIG_SORTERREF_SIZE]] 1971** <dt>SQLITE_CONFIG_SORTERREF_SIZE 1972** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 1973** of type (int) - the new value of the sorter-reference size threshold. 1974** Usually, when SQLite uses an external sort to order records according 1975** to an ORDER BY clause, all fields required by the caller are present in the 1976** sorted records. However, if SQLite determines based on the declared type 1977** of a table column that its values are likely to be very large - larger 1978** than the configured sorter-reference size threshold - then a reference 1979** is stored in each sorted record and the required column values loaded 1980** from the database as records are returned in sorted order. The default 1981** value for this option is to never use this optimization. Specifying a 1982** negative value for this option restores the default behaviour. 1983** This option is only available if SQLite is compiled with the 1984** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 1985** 1986** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 1987** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 1988** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 1989** [sqlite3_int64] parameter which is the default maximum size for an in-memory 1990** database created using [sqlite3_deserialize()]. This default maximum 1991** size can be adjusted up or down for individual databases using the 1992** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 1993** configuration setting is never used, then the default maximum is determined 1994** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 1995** compile-time option is not set, then the default maximum is 1073741824. 1996** </dl> 1997*/ 1998#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1999#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2000#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2001#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2002#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2003#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2004#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2005#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2006#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2007#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2008#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2009/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2010#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2011#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2012#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2013#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2014#define SQLITE_CONFIG_URI 17 /* int */ 2015#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2016#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2017#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2018#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2019#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2020#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2021#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2022#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2023#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2024#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2025#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2026#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2027 2028/* 2029** CAPI3REF: Database Connection Configuration Options 2030** 2031** These constants are the available integer configuration options that 2032** can be passed as the second argument to the [sqlite3_db_config()] interface. 2033** 2034** New configuration options may be added in future releases of SQLite. 2035** Existing configuration options might be discontinued. Applications 2036** should check the return code from [sqlite3_db_config()] to make sure that 2037** the call worked. ^The [sqlite3_db_config()] interface will return a 2038** non-zero [error code] if a discontinued or unsupported configuration option 2039** is invoked. 2040** 2041** <dl> 2042** [[SQLITE_DBCONFIG_LOOKASIDE]] 2043** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2044** <dd> ^This option takes three additional arguments that determine the 2045** [lookaside memory allocator] configuration for the [database connection]. 2046** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2047** pointer to a memory buffer to use for lookaside memory. 2048** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2049** may be NULL in which case SQLite will allocate the 2050** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2051** size of each lookaside buffer slot. ^The third argument is the number of 2052** slots. The size of the buffer in the first argument must be greater than 2053** or equal to the product of the second and third arguments. The buffer 2054** must be aligned to an 8-byte boundary. ^If the second argument to 2055** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2056** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2057** configuration for a database connection can only be changed when that 2058** connection is not currently using lookaside memory, or in other words 2059** when the "current value" returned by 2060** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2061** Any attempt to change the lookaside memory configuration when lookaside 2062** memory is in use leaves the configuration unchanged and returns 2063** [SQLITE_BUSY].)^</dd> 2064** 2065** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2066** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2067** <dd> ^This option is used to enable or disable the enforcement of 2068** [foreign key constraints]. There should be two additional arguments. 2069** The first argument is an integer which is 0 to disable FK enforcement, 2070** positive to enable FK enforcement or negative to leave FK enforcement 2071** unchanged. The second parameter is a pointer to an integer into which 2072** is written 0 or 1 to indicate whether FK enforcement is off or on 2073** following this call. The second parameter may be a NULL pointer, in 2074** which case the FK enforcement setting is not reported back. </dd> 2075** 2076** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2077** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2078** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2079** There should be two additional arguments. 2080** The first argument is an integer which is 0 to disable triggers, 2081** positive to enable triggers or negative to leave the setting unchanged. 2082** The second parameter is a pointer to an integer into which 2083** is written 0 or 1 to indicate whether triggers are disabled or enabled 2084** following this call. The second parameter may be a NULL pointer, in 2085** which case the trigger setting is not reported back. </dd> 2086** 2087** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2088** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2089** <dd> ^This option is used to enable or disable the 2090** [fts3_tokenizer()] function which is part of the 2091** [FTS3] full-text search engine extension. 2092** There should be two additional arguments. 2093** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2094** positive to enable fts3_tokenizer() or negative to leave the setting 2095** unchanged. 2096** The second parameter is a pointer to an integer into which 2097** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2098** following this call. The second parameter may be a NULL pointer, in 2099** which case the new setting is not reported back. </dd> 2100** 2101** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2102** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2103** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2104** interface independently of the [load_extension()] SQL function. 2105** The [sqlite3_enable_load_extension()] API enables or disables both the 2106** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2107** There should be two additional arguments. 2108** When the first argument to this interface is 1, then only the C-API is 2109** enabled and the SQL function remains disabled. If the first argument to 2110** this interface is 0, then both the C-API and the SQL function are disabled. 2111** If the first argument is -1, then no changes are made to state of either the 2112** C-API or the SQL function. 2113** The second parameter is a pointer to an integer into which 2114** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2115** is disabled or enabled following this call. The second parameter may 2116** be a NULL pointer, in which case the new setting is not reported back. 2117** </dd> 2118** 2119** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2120** <dd> ^This option is used to change the name of the "main" database 2121** schema. ^The sole argument is a pointer to a constant UTF8 string 2122** which will become the new schema name in place of "main". ^SQLite 2123** does not make a copy of the new main schema name string, so the application 2124** must ensure that the argument passed into this DBCONFIG option is unchanged 2125** until after the database connection closes. 2126** </dd> 2127** 2128** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2129** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2130** <dd> Usually, when a database in wal mode is closed or detached from a 2131** database handle, SQLite checks if this will mean that there are now no 2132** connections at all to the database. If so, it performs a checkpoint 2133** operation before closing the connection. This option may be used to 2134** override this behaviour. The first parameter passed to this operation 2135** is an integer - positive to disable checkpoints-on-close, or zero (the 2136** default) to enable them, and negative to leave the setting unchanged. 2137** The second parameter is a pointer to an integer 2138** into which is written 0 or 1 to indicate whether checkpoints-on-close 2139** have been disabled - 0 if they are not disabled, 1 if they are. 2140** </dd> 2141** 2142** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2143** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2144** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2145** a single SQL query statement will always use the same algorithm regardless 2146** of values of [bound parameters].)^ The QPSG disables some query optimizations 2147** that look at the values of bound parameters, which can make some queries 2148** slower. But the QPSG has the advantage of more predictable behavior. With 2149** the QPSG active, SQLite will always use the same query plan in the field as 2150** was used during testing in the lab. 2151** The first argument to this setting is an integer which is 0 to disable 2152** the QPSG, positive to enable QPSG, or negative to leave the setting 2153** unchanged. The second parameter is a pointer to an integer into which 2154** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2155** following this call. 2156** </dd> 2157** 2158** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2159** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2160** include output for any operations performed by trigger programs. This 2161** option is used to set or clear (the default) a flag that governs this 2162** behavior. The first parameter passed to this operation is an integer - 2163** positive to enable output for trigger programs, or zero to disable it, 2164** or negative to leave the setting unchanged. 2165** The second parameter is a pointer to an integer into which is written 2166** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2167** it is not disabled, 1 if it is. 2168** </dd> 2169** 2170** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2171** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2172** [VACUUM] in order to reset a database back to an empty database 2173** with no schema and no content. The following process works even for 2174** a badly corrupted database file: 2175** <ol> 2176** <li> If the database connection is newly opened, make sure it has read the 2177** database schema by preparing then discarding some query against the 2178** database, or calling sqlite3_table_column_metadata(), ignoring any 2179** errors. This step is only necessary if the application desires to keep 2180** the database in WAL mode after the reset if it was in WAL mode before 2181** the reset. 2182** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2183** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2184** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2185** </ol> 2186** Because resetting a database is destructive and irreversible, the 2187** process requires the use of this obscure API and multiple steps to help 2188** ensure that it does not happen by accident. 2189** 2190** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2191** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2192** "defensive" flag for a database connection. When the defensive 2193** flag is enabled, language features that allow ordinary SQL to 2194** deliberately corrupt the database file are disabled. The disabled 2195** features include but are not limited to the following: 2196** <ul> 2197** <li> The [PRAGMA writable_schema=ON] statement. 2198** <li> Writes to the [sqlite_dbpage] virtual table. 2199** <li> Direct writes to [shadow tables]. 2200** </ul> 2201** </dd> 2202** </dl> 2203*/ 2204#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2205#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2206#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2207#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2208#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2209#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2210#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2211#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2212#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2213#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2214#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2215#define SQLITE_DBCONFIG_MAX 1010 /* Largest DBCONFIG */ 2216 2217/* 2218** CAPI3REF: Enable Or Disable Extended Result Codes 2219** METHOD: sqlite3 2220** 2221** ^The sqlite3_extended_result_codes() routine enables or disables the 2222** [extended result codes] feature of SQLite. ^The extended result 2223** codes are disabled by default for historical compatibility. 2224*/ 2225int sqlite3_extended_result_codes(sqlite3*, int onoff); 2226 2227/* 2228** CAPI3REF: Last Insert Rowid 2229** METHOD: sqlite3 2230** 2231** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2232** has a unique 64-bit signed 2233** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2234** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2235** names are not also used by explicitly declared columns. ^If 2236** the table has a column of type [INTEGER PRIMARY KEY] then that column 2237** is another alias for the rowid. 2238** 2239** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2240** the most recent successful [INSERT] into a rowid table or [virtual table] 2241** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2242** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2243** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2244** zero. 2245** 2246** As well as being set automatically as rows are inserted into database 2247** tables, the value returned by this function may be set explicitly by 2248** [sqlite3_set_last_insert_rowid()] 2249** 2250** Some virtual table implementations may INSERT rows into rowid tables as 2251** part of committing a transaction (e.g. to flush data accumulated in memory 2252** to disk). In this case subsequent calls to this function return the rowid 2253** associated with these internal INSERT operations, which leads to 2254** unintuitive results. Virtual table implementations that do write to rowid 2255** tables in this way can avoid this problem by restoring the original 2256** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2257** control to the user. 2258** 2259** ^(If an [INSERT] occurs within a trigger then this routine will 2260** return the [rowid] of the inserted row as long as the trigger is 2261** running. Once the trigger program ends, the value returned 2262** by this routine reverts to what it was before the trigger was fired.)^ 2263** 2264** ^An [INSERT] that fails due to a constraint violation is not a 2265** successful [INSERT] and does not change the value returned by this 2266** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2267** and INSERT OR ABORT make no changes to the return value of this 2268** routine when their insertion fails. ^(When INSERT OR REPLACE 2269** encounters a constraint violation, it does not fail. The 2270** INSERT continues to completion after deleting rows that caused 2271** the constraint problem so INSERT OR REPLACE will always change 2272** the return value of this interface.)^ 2273** 2274** ^For the purposes of this routine, an [INSERT] is considered to 2275** be successful even if it is subsequently rolled back. 2276** 2277** This function is accessible to SQL statements via the 2278** [last_insert_rowid() SQL function]. 2279** 2280** If a separate thread performs a new [INSERT] on the same 2281** database connection while the [sqlite3_last_insert_rowid()] 2282** function is running and thus changes the last insert [rowid], 2283** then the value returned by [sqlite3_last_insert_rowid()] is 2284** unpredictable and might not equal either the old or the new 2285** last insert [rowid]. 2286*/ 2287sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2288 2289/* 2290** CAPI3REF: Set the Last Insert Rowid value. 2291** METHOD: sqlite3 2292** 2293** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2294** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2295** without inserting a row into the database. 2296*/ 2297void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2298 2299/* 2300** CAPI3REF: Count The Number Of Rows Modified 2301** METHOD: sqlite3 2302** 2303** ^This function returns the number of rows modified, inserted or 2304** deleted by the most recently completed INSERT, UPDATE or DELETE 2305** statement on the database connection specified by the only parameter. 2306** ^Executing any other type of SQL statement does not modify the value 2307** returned by this function. 2308** 2309** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2310** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2311** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2312** 2313** Changes to a view that are intercepted by 2314** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2315** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2316** DELETE statement run on a view is always zero. Only changes made to real 2317** tables are counted. 2318** 2319** Things are more complicated if the sqlite3_changes() function is 2320** executed while a trigger program is running. This may happen if the 2321** program uses the [changes() SQL function], or if some other callback 2322** function invokes sqlite3_changes() directly. Essentially: 2323** 2324** <ul> 2325** <li> ^(Before entering a trigger program the value returned by 2326** sqlite3_changes() function is saved. After the trigger program 2327** has finished, the original value is restored.)^ 2328** 2329** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2330** statement sets the value returned by sqlite3_changes() 2331** upon completion as normal. Of course, this value will not include 2332** any changes performed by sub-triggers, as the sqlite3_changes() 2333** value will be saved and restored after each sub-trigger has run.)^ 2334** </ul> 2335** 2336** ^This means that if the changes() SQL function (or similar) is used 2337** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2338** returns the value as set when the calling statement began executing. 2339** ^If it is used by the second or subsequent such statement within a trigger 2340** program, the value returned reflects the number of rows modified by the 2341** previous INSERT, UPDATE or DELETE statement within the same trigger. 2342** 2343** If a separate thread makes changes on the same database connection 2344** while [sqlite3_changes()] is running then the value returned 2345** is unpredictable and not meaningful. 2346** 2347** See also: 2348** <ul> 2349** <li> the [sqlite3_total_changes()] interface 2350** <li> the [count_changes pragma] 2351** <li> the [changes() SQL function] 2352** <li> the [data_version pragma] 2353** </ul> 2354*/ 2355int sqlite3_changes(sqlite3*); 2356 2357/* 2358** CAPI3REF: Total Number Of Rows Modified 2359** METHOD: sqlite3 2360** 2361** ^This function returns the total number of rows inserted, modified or 2362** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2363** since the database connection was opened, including those executed as 2364** part of trigger programs. ^Executing any other type of SQL statement 2365** does not affect the value returned by sqlite3_total_changes(). 2366** 2367** ^Changes made as part of [foreign key actions] are included in the 2368** count, but those made as part of REPLACE constraint resolution are 2369** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2370** are not counted. 2371** 2372** The [sqlite3_total_changes(D)] interface only reports the number 2373** of rows that changed due to SQL statement run against database 2374** connection D. Any changes by other database connections are ignored. 2375** To detect changes against a database file from other database 2376** connections use the [PRAGMA data_version] command or the 2377** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2378** 2379** If a separate thread makes changes on the same database connection 2380** while [sqlite3_total_changes()] is running then the value 2381** returned is unpredictable and not meaningful. 2382** 2383** See also: 2384** <ul> 2385** <li> the [sqlite3_changes()] interface 2386** <li> the [count_changes pragma] 2387** <li> the [changes() SQL function] 2388** <li> the [data_version pragma] 2389** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2390** </ul> 2391*/ 2392int sqlite3_total_changes(sqlite3*); 2393 2394/* 2395** CAPI3REF: Interrupt A Long-Running Query 2396** METHOD: sqlite3 2397** 2398** ^This function causes any pending database operation to abort and 2399** return at its earliest opportunity. This routine is typically 2400** called in response to a user action such as pressing "Cancel" 2401** or Ctrl-C where the user wants a long query operation to halt 2402** immediately. 2403** 2404** ^It is safe to call this routine from a thread different from the 2405** thread that is currently running the database operation. But it 2406** is not safe to call this routine with a [database connection] that 2407** is closed or might close before sqlite3_interrupt() returns. 2408** 2409** ^If an SQL operation is very nearly finished at the time when 2410** sqlite3_interrupt() is called, then it might not have an opportunity 2411** to be interrupted and might continue to completion. 2412** 2413** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2414** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2415** that is inside an explicit transaction, then the entire transaction 2416** will be rolled back automatically. 2417** 2418** ^The sqlite3_interrupt(D) call is in effect until all currently running 2419** SQL statements on [database connection] D complete. ^Any new SQL statements 2420** that are started after the sqlite3_interrupt() call and before the 2421** running statements reaches zero are interrupted as if they had been 2422** running prior to the sqlite3_interrupt() call. ^New SQL statements 2423** that are started after the running statement count reaches zero are 2424** not effected by the sqlite3_interrupt(). 2425** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2426** SQL statements is a no-op and has no effect on SQL statements 2427** that are started after the sqlite3_interrupt() call returns. 2428*/ 2429void sqlite3_interrupt(sqlite3*); 2430 2431/* 2432** CAPI3REF: Determine If An SQL Statement Is Complete 2433** 2434** These routines are useful during command-line input to determine if the 2435** currently entered text seems to form a complete SQL statement or 2436** if additional input is needed before sending the text into 2437** SQLite for parsing. ^These routines return 1 if the input string 2438** appears to be a complete SQL statement. ^A statement is judged to be 2439** complete if it ends with a semicolon token and is not a prefix of a 2440** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2441** string literals or quoted identifier names or comments are not 2442** independent tokens (they are part of the token in which they are 2443** embedded) and thus do not count as a statement terminator. ^Whitespace 2444** and comments that follow the final semicolon are ignored. 2445** 2446** ^These routines return 0 if the statement is incomplete. ^If a 2447** memory allocation fails, then SQLITE_NOMEM is returned. 2448** 2449** ^These routines do not parse the SQL statements thus 2450** will not detect syntactically incorrect SQL. 2451** 2452** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2453** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2454** automatically by sqlite3_complete16(). If that initialization fails, 2455** then the return value from sqlite3_complete16() will be non-zero 2456** regardless of whether or not the input SQL is complete.)^ 2457** 2458** The input to [sqlite3_complete()] must be a zero-terminated 2459** UTF-8 string. 2460** 2461** The input to [sqlite3_complete16()] must be a zero-terminated 2462** UTF-16 string in native byte order. 2463*/ 2464int sqlite3_complete(const char *sql); 2465int sqlite3_complete16(const void *sql); 2466 2467/* 2468** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2469** KEYWORDS: {busy-handler callback} {busy handler} 2470** METHOD: sqlite3 2471** 2472** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2473** that might be invoked with argument P whenever 2474** an attempt is made to access a database table associated with 2475** [database connection] D when another thread 2476** or process has the table locked. 2477** The sqlite3_busy_handler() interface is used to implement 2478** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2479** 2480** ^If the busy callback is NULL, then [SQLITE_BUSY] 2481** is returned immediately upon encountering the lock. ^If the busy callback 2482** is not NULL, then the callback might be invoked with two arguments. 2483** 2484** ^The first argument to the busy handler is a copy of the void* pointer which 2485** is the third argument to sqlite3_busy_handler(). ^The second argument to 2486** the busy handler callback is the number of times that the busy handler has 2487** been invoked previously for the same locking event. ^If the 2488** busy callback returns 0, then no additional attempts are made to 2489** access the database and [SQLITE_BUSY] is returned 2490** to the application. 2491** ^If the callback returns non-zero, then another attempt 2492** is made to access the database and the cycle repeats. 2493** 2494** The presence of a busy handler does not guarantee that it will be invoked 2495** when there is lock contention. ^If SQLite determines that invoking the busy 2496** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2497** to the application instead of invoking the 2498** busy handler. 2499** Consider a scenario where one process is holding a read lock that 2500** it is trying to promote to a reserved lock and 2501** a second process is holding a reserved lock that it is trying 2502** to promote to an exclusive lock. The first process cannot proceed 2503** because it is blocked by the second and the second process cannot 2504** proceed because it is blocked by the first. If both processes 2505** invoke the busy handlers, neither will make any progress. Therefore, 2506** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2507** will induce the first process to release its read lock and allow 2508** the second process to proceed. 2509** 2510** ^The default busy callback is NULL. 2511** 2512** ^(There can only be a single busy handler defined for each 2513** [database connection]. Setting a new busy handler clears any 2514** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2515** or evaluating [PRAGMA busy_timeout=N] will change the 2516** busy handler and thus clear any previously set busy handler. 2517** 2518** The busy callback should not take any actions which modify the 2519** database connection that invoked the busy handler. In other words, 2520** the busy handler is not reentrant. Any such actions 2521** result in undefined behavior. 2522** 2523** A busy handler must not close the database connection 2524** or [prepared statement] that invoked the busy handler. 2525*/ 2526int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2527 2528/* 2529** CAPI3REF: Set A Busy Timeout 2530** METHOD: sqlite3 2531** 2532** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2533** for a specified amount of time when a table is locked. ^The handler 2534** will sleep multiple times until at least "ms" milliseconds of sleeping 2535** have accumulated. ^After at least "ms" milliseconds of sleeping, 2536** the handler returns 0 which causes [sqlite3_step()] to return 2537** [SQLITE_BUSY]. 2538** 2539** ^Calling this routine with an argument less than or equal to zero 2540** turns off all busy handlers. 2541** 2542** ^(There can only be a single busy handler for a particular 2543** [database connection] at any given moment. If another busy handler 2544** was defined (using [sqlite3_busy_handler()]) prior to calling 2545** this routine, that other busy handler is cleared.)^ 2546** 2547** See also: [PRAGMA busy_timeout] 2548*/ 2549int sqlite3_busy_timeout(sqlite3*, int ms); 2550 2551/* 2552** CAPI3REF: Convenience Routines For Running Queries 2553** METHOD: sqlite3 2554** 2555** This is a legacy interface that is preserved for backwards compatibility. 2556** Use of this interface is not recommended. 2557** 2558** Definition: A <b>result table</b> is memory data structure created by the 2559** [sqlite3_get_table()] interface. A result table records the 2560** complete query results from one or more queries. 2561** 2562** The table conceptually has a number of rows and columns. But 2563** these numbers are not part of the result table itself. These 2564** numbers are obtained separately. Let N be the number of rows 2565** and M be the number of columns. 2566** 2567** A result table is an array of pointers to zero-terminated UTF-8 strings. 2568** There are (N+1)*M elements in the array. The first M pointers point 2569** to zero-terminated strings that contain the names of the columns. 2570** The remaining entries all point to query results. NULL values result 2571** in NULL pointers. All other values are in their UTF-8 zero-terminated 2572** string representation as returned by [sqlite3_column_text()]. 2573** 2574** A result table might consist of one or more memory allocations. 2575** It is not safe to pass a result table directly to [sqlite3_free()]. 2576** A result table should be deallocated using [sqlite3_free_table()]. 2577** 2578** ^(As an example of the result table format, suppose a query result 2579** is as follows: 2580** 2581** <blockquote><pre> 2582** Name | Age 2583** ----------------------- 2584** Alice | 43 2585** Bob | 28 2586** Cindy | 21 2587** </pre></blockquote> 2588** 2589** There are two column (M==2) and three rows (N==3). Thus the 2590** result table has 8 entries. Suppose the result table is stored 2591** in an array names azResult. Then azResult holds this content: 2592** 2593** <blockquote><pre> 2594** azResult[0] = "Name"; 2595** azResult[1] = "Age"; 2596** azResult[2] = "Alice"; 2597** azResult[3] = "43"; 2598** azResult[4] = "Bob"; 2599** azResult[5] = "28"; 2600** azResult[6] = "Cindy"; 2601** azResult[7] = "21"; 2602** </pre></blockquote>)^ 2603** 2604** ^The sqlite3_get_table() function evaluates one or more 2605** semicolon-separated SQL statements in the zero-terminated UTF-8 2606** string of its 2nd parameter and returns a result table to the 2607** pointer given in its 3rd parameter. 2608** 2609** After the application has finished with the result from sqlite3_get_table(), 2610** it must pass the result table pointer to sqlite3_free_table() in order to 2611** release the memory that was malloced. Because of the way the 2612** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2613** function must not try to call [sqlite3_free()] directly. Only 2614** [sqlite3_free_table()] is able to release the memory properly and safely. 2615** 2616** The sqlite3_get_table() interface is implemented as a wrapper around 2617** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2618** to any internal data structures of SQLite. It uses only the public 2619** interface defined here. As a consequence, errors that occur in the 2620** wrapper layer outside of the internal [sqlite3_exec()] call are not 2621** reflected in subsequent calls to [sqlite3_errcode()] or 2622** [sqlite3_errmsg()]. 2623*/ 2624int sqlite3_get_table( 2625 sqlite3 *db, /* An open database */ 2626 const char *zSql, /* SQL to be evaluated */ 2627 char ***pazResult, /* Results of the query */ 2628 int *pnRow, /* Number of result rows written here */ 2629 int *pnColumn, /* Number of result columns written here */ 2630 char **pzErrmsg /* Error msg written here */ 2631); 2632void sqlite3_free_table(char **result); 2633 2634/* 2635** CAPI3REF: Formatted String Printing Functions 2636** 2637** These routines are work-alikes of the "printf()" family of functions 2638** from the standard C library. 2639** These routines understand most of the common formatting options from 2640** the standard library printf() 2641** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2642** See the [built-in printf()] documentation for details. 2643** 2644** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2645** results into memory obtained from [sqlite3_malloc64()]. 2646** The strings returned by these two routines should be 2647** released by [sqlite3_free()]. ^Both routines return a 2648** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2649** memory to hold the resulting string. 2650** 2651** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2652** the standard C library. The result is written into the 2653** buffer supplied as the second parameter whose size is given by 2654** the first parameter. Note that the order of the 2655** first two parameters is reversed from snprintf().)^ This is an 2656** historical accident that cannot be fixed without breaking 2657** backwards compatibility. ^(Note also that sqlite3_snprintf() 2658** returns a pointer to its buffer instead of the number of 2659** characters actually written into the buffer.)^ We admit that 2660** the number of characters written would be a more useful return 2661** value but we cannot change the implementation of sqlite3_snprintf() 2662** now without breaking compatibility. 2663** 2664** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2665** guarantees that the buffer is always zero-terminated. ^The first 2666** parameter "n" is the total size of the buffer, including space for 2667** the zero terminator. So the longest string that can be completely 2668** written will be n-1 characters. 2669** 2670** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2671** 2672** See also: [built-in printf()], [printf() SQL function] 2673*/ 2674char *sqlite3_mprintf(const char*,...); 2675char *sqlite3_vmprintf(const char*, va_list); 2676char *sqlite3_snprintf(int,char*,const char*, ...); 2677char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2678 2679/* 2680** CAPI3REF: Memory Allocation Subsystem 2681** 2682** The SQLite core uses these three routines for all of its own 2683** internal memory allocation needs. "Core" in the previous sentence 2684** does not include operating-system specific VFS implementation. The 2685** Windows VFS uses native malloc() and free() for some operations. 2686** 2687** ^The sqlite3_malloc() routine returns a pointer to a block 2688** of memory at least N bytes in length, where N is the parameter. 2689** ^If sqlite3_malloc() is unable to obtain sufficient free 2690** memory, it returns a NULL pointer. ^If the parameter N to 2691** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2692** a NULL pointer. 2693** 2694** ^The sqlite3_malloc64(N) routine works just like 2695** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2696** of a signed 32-bit integer. 2697** 2698** ^Calling sqlite3_free() with a pointer previously returned 2699** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2700** that it might be reused. ^The sqlite3_free() routine is 2701** a no-op if is called with a NULL pointer. Passing a NULL pointer 2702** to sqlite3_free() is harmless. After being freed, memory 2703** should neither be read nor written. Even reading previously freed 2704** memory might result in a segmentation fault or other severe error. 2705** Memory corruption, a segmentation fault, or other severe error 2706** might result if sqlite3_free() is called with a non-NULL pointer that 2707** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2708** 2709** ^The sqlite3_realloc(X,N) interface attempts to resize a 2710** prior memory allocation X to be at least N bytes. 2711** ^If the X parameter to sqlite3_realloc(X,N) 2712** is a NULL pointer then its behavior is identical to calling 2713** sqlite3_malloc(N). 2714** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2715** negative then the behavior is exactly the same as calling 2716** sqlite3_free(X). 2717** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2718** of at least N bytes in size or NULL if insufficient memory is available. 2719** ^If M is the size of the prior allocation, then min(N,M) bytes 2720** of the prior allocation are copied into the beginning of buffer returned 2721** by sqlite3_realloc(X,N) and the prior allocation is freed. 2722** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2723** prior allocation is not freed. 2724** 2725** ^The sqlite3_realloc64(X,N) interfaces works the same as 2726** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2727** of a 32-bit signed integer. 2728** 2729** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2730** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2731** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2732** ^The value returned by sqlite3_msize(X) might be larger than the number 2733** of bytes requested when X was allocated. ^If X is a NULL pointer then 2734** sqlite3_msize(X) returns zero. If X points to something that is not 2735** the beginning of memory allocation, or if it points to a formerly 2736** valid memory allocation that has now been freed, then the behavior 2737** of sqlite3_msize(X) is undefined and possibly harmful. 2738** 2739** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2740** sqlite3_malloc64(), and sqlite3_realloc64() 2741** is always aligned to at least an 8 byte boundary, or to a 2742** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2743** option is used. 2744** 2745** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2746** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2747** implementation of these routines to be omitted. That capability 2748** is no longer provided. Only built-in memory allocators can be used. 2749** 2750** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2751** the system malloc() and free() directly when converting 2752** filenames between the UTF-8 encoding used by SQLite 2753** and whatever filename encoding is used by the particular Windows 2754** installation. Memory allocation errors were detected, but 2755** they were reported back as [SQLITE_CANTOPEN] or 2756** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2757** 2758** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2759** must be either NULL or else pointers obtained from a prior 2760** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2761** not yet been released. 2762** 2763** The application must not read or write any part of 2764** a block of memory after it has been released using 2765** [sqlite3_free()] or [sqlite3_realloc()]. 2766*/ 2767void *sqlite3_malloc(int); 2768void *sqlite3_malloc64(sqlite3_uint64); 2769void *sqlite3_realloc(void*, int); 2770void *sqlite3_realloc64(void*, sqlite3_uint64); 2771void sqlite3_free(void*); 2772sqlite3_uint64 sqlite3_msize(void*); 2773 2774/* 2775** CAPI3REF: Memory Allocator Statistics 2776** 2777** SQLite provides these two interfaces for reporting on the status 2778** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2779** routines, which form the built-in memory allocation subsystem. 2780** 2781** ^The [sqlite3_memory_used()] routine returns the number of bytes 2782** of memory currently outstanding (malloced but not freed). 2783** ^The [sqlite3_memory_highwater()] routine returns the maximum 2784** value of [sqlite3_memory_used()] since the high-water mark 2785** was last reset. ^The values returned by [sqlite3_memory_used()] and 2786** [sqlite3_memory_highwater()] include any overhead 2787** added by SQLite in its implementation of [sqlite3_malloc()], 2788** but not overhead added by the any underlying system library 2789** routines that [sqlite3_malloc()] may call. 2790** 2791** ^The memory high-water mark is reset to the current value of 2792** [sqlite3_memory_used()] if and only if the parameter to 2793** [sqlite3_memory_highwater()] is true. ^The value returned 2794** by [sqlite3_memory_highwater(1)] is the high-water mark 2795** prior to the reset. 2796*/ 2797sqlite3_int64 sqlite3_memory_used(void); 2798sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2799 2800/* 2801** CAPI3REF: Pseudo-Random Number Generator 2802** 2803** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2804** select random [ROWID | ROWIDs] when inserting new records into a table that 2805** already uses the largest possible [ROWID]. The PRNG is also used for 2806** the build-in random() and randomblob() SQL functions. This interface allows 2807** applications to access the same PRNG for other purposes. 2808** 2809** ^A call to this routine stores N bytes of randomness into buffer P. 2810** ^The P parameter can be a NULL pointer. 2811** 2812** ^If this routine has not been previously called or if the previous 2813** call had N less than one or a NULL pointer for P, then the PRNG is 2814** seeded using randomness obtained from the xRandomness method of 2815** the default [sqlite3_vfs] object. 2816** ^If the previous call to this routine had an N of 1 or more and a 2817** non-NULL P then the pseudo-randomness is generated 2818** internally and without recourse to the [sqlite3_vfs] xRandomness 2819** method. 2820*/ 2821void sqlite3_randomness(int N, void *P); 2822 2823/* 2824** CAPI3REF: Compile-Time Authorization Callbacks 2825** METHOD: sqlite3 2826** KEYWORDS: {authorizer callback} 2827** 2828** ^This routine registers an authorizer callback with a particular 2829** [database connection], supplied in the first argument. 2830** ^The authorizer callback is invoked as SQL statements are being compiled 2831** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2832** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2833** and [sqlite3_prepare16_v3()]. ^At various 2834** points during the compilation process, as logic is being created 2835** to perform various actions, the authorizer callback is invoked to 2836** see if those actions are allowed. ^The authorizer callback should 2837** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2838** specific action but allow the SQL statement to continue to be 2839** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2840** rejected with an error. ^If the authorizer callback returns 2841** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2842** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2843** the authorizer will fail with an error message. 2844** 2845** When the callback returns [SQLITE_OK], that means the operation 2846** requested is ok. ^When the callback returns [SQLITE_DENY], the 2847** [sqlite3_prepare_v2()] or equivalent call that triggered the 2848** authorizer will fail with an error message explaining that 2849** access is denied. 2850** 2851** ^The first parameter to the authorizer callback is a copy of the third 2852** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2853** to the callback is an integer [SQLITE_COPY | action code] that specifies 2854** the particular action to be authorized. ^The third through sixth parameters 2855** to the callback are either NULL pointers or zero-terminated strings 2856** that contain additional details about the action to be authorized. 2857** Applications must always be prepared to encounter a NULL pointer in any 2858** of the third through the sixth parameters of the authorization callback. 2859** 2860** ^If the action code is [SQLITE_READ] 2861** and the callback returns [SQLITE_IGNORE] then the 2862** [prepared statement] statement is constructed to substitute 2863** a NULL value in place of the table column that would have 2864** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2865** return can be used to deny an untrusted user access to individual 2866** columns of a table. 2867** ^When a table is referenced by a [SELECT] but no column values are 2868** extracted from that table (for example in a query like 2869** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2870** is invoked once for that table with a column name that is an empty string. 2871** ^If the action code is [SQLITE_DELETE] and the callback returns 2872** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2873** [truncate optimization] is disabled and all rows are deleted individually. 2874** 2875** An authorizer is used when [sqlite3_prepare | preparing] 2876** SQL statements from an untrusted source, to ensure that the SQL statements 2877** do not try to access data they are not allowed to see, or that they do not 2878** try to execute malicious statements that damage the database. For 2879** example, an application may allow a user to enter arbitrary 2880** SQL queries for evaluation by a database. But the application does 2881** not want the user to be able to make arbitrary changes to the 2882** database. An authorizer could then be put in place while the 2883** user-entered SQL is being [sqlite3_prepare | prepared] that 2884** disallows everything except [SELECT] statements. 2885** 2886** Applications that need to process SQL from untrusted sources 2887** might also consider lowering resource limits using [sqlite3_limit()] 2888** and limiting database size using the [max_page_count] [PRAGMA] 2889** in addition to using an authorizer. 2890** 2891** ^(Only a single authorizer can be in place on a database connection 2892** at a time. Each call to sqlite3_set_authorizer overrides the 2893** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2894** The authorizer is disabled by default. 2895** 2896** The authorizer callback must not do anything that will modify 2897** the database connection that invoked the authorizer callback. 2898** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2899** database connections for the meaning of "modify" in this paragraph. 2900** 2901** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2902** statement might be re-prepared during [sqlite3_step()] due to a 2903** schema change. Hence, the application should ensure that the 2904** correct authorizer callback remains in place during the [sqlite3_step()]. 2905** 2906** ^Note that the authorizer callback is invoked only during 2907** [sqlite3_prepare()] or its variants. Authorization is not 2908** performed during statement evaluation in [sqlite3_step()], unless 2909** as stated in the previous paragraph, sqlite3_step() invokes 2910** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2911*/ 2912int sqlite3_set_authorizer( 2913 sqlite3*, 2914 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2915 void *pUserData 2916); 2917 2918/* 2919** CAPI3REF: Authorizer Return Codes 2920** 2921** The [sqlite3_set_authorizer | authorizer callback function] must 2922** return either [SQLITE_OK] or one of these two constants in order 2923** to signal SQLite whether or not the action is permitted. See the 2924** [sqlite3_set_authorizer | authorizer documentation] for additional 2925** information. 2926** 2927** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2928** returned from the [sqlite3_vtab_on_conflict()] interface. 2929*/ 2930#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2931#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2932 2933/* 2934** CAPI3REF: Authorizer Action Codes 2935** 2936** The [sqlite3_set_authorizer()] interface registers a callback function 2937** that is invoked to authorize certain SQL statement actions. The 2938** second parameter to the callback is an integer code that specifies 2939** what action is being authorized. These are the integer action codes that 2940** the authorizer callback may be passed. 2941** 2942** These action code values signify what kind of operation is to be 2943** authorized. The 3rd and 4th parameters to the authorization 2944** callback function will be parameters or NULL depending on which of these 2945** codes is used as the second parameter. ^(The 5th parameter to the 2946** authorizer callback is the name of the database ("main", "temp", 2947** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2948** is the name of the inner-most trigger or view that is responsible for 2949** the access attempt or NULL if this access attempt is directly from 2950** top-level SQL code. 2951*/ 2952/******************************************* 3rd ************ 4th ***********/ 2953#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2954#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2955#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2956#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2957#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2958#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2959#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2960#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2961#define SQLITE_DELETE 9 /* Table Name NULL */ 2962#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2963#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2964#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2965#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2966#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2967#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2968#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2969#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2970#define SQLITE_INSERT 18 /* Table Name NULL */ 2971#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2972#define SQLITE_READ 20 /* Table Name Column Name */ 2973#define SQLITE_SELECT 21 /* NULL NULL */ 2974#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2975#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2976#define SQLITE_ATTACH 24 /* Filename NULL */ 2977#define SQLITE_DETACH 25 /* Database Name NULL */ 2978#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2979#define SQLITE_REINDEX 27 /* Index Name NULL */ 2980#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2981#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2982#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2983#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2984#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2985#define SQLITE_COPY 0 /* No longer used */ 2986#define SQLITE_RECURSIVE 33 /* NULL NULL */ 2987 2988/* 2989** CAPI3REF: Tracing And Profiling Functions 2990** METHOD: sqlite3 2991** 2992** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 2993** instead of the routines described here. 2994** 2995** These routines register callback functions that can be used for 2996** tracing and profiling the execution of SQL statements. 2997** 2998** ^The callback function registered by sqlite3_trace() is invoked at 2999** various times when an SQL statement is being run by [sqlite3_step()]. 3000** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3001** SQL statement text as the statement first begins executing. 3002** ^(Additional sqlite3_trace() callbacks might occur 3003** as each triggered subprogram is entered. The callbacks for triggers 3004** contain a UTF-8 SQL comment that identifies the trigger.)^ 3005** 3006** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3007** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3008** 3009** ^The callback function registered by sqlite3_profile() is invoked 3010** as each SQL statement finishes. ^The profile callback contains 3011** the original statement text and an estimate of wall-clock time 3012** of how long that statement took to run. ^The profile callback 3013** time is in units of nanoseconds, however the current implementation 3014** is only capable of millisecond resolution so the six least significant 3015** digits in the time are meaningless. Future versions of SQLite 3016** might provide greater resolution on the profiler callback. Invoking 3017** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3018** profile callback. 3019*/ 3020SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3021 void(*xTrace)(void*,const char*), void*); 3022SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3023 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3024 3025/* 3026** CAPI3REF: SQL Trace Event Codes 3027** KEYWORDS: SQLITE_TRACE 3028** 3029** These constants identify classes of events that can be monitored 3030** using the [sqlite3_trace_v2()] tracing logic. The M argument 3031** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3032** the following constants. ^The first argument to the trace callback 3033** is one of the following constants. 3034** 3035** New tracing constants may be added in future releases. 3036** 3037** ^A trace callback has four arguments: xCallback(T,C,P,X). 3038** ^The T argument is one of the integer type codes above. 3039** ^The C argument is a copy of the context pointer passed in as the 3040** fourth argument to [sqlite3_trace_v2()]. 3041** The P and X arguments are pointers whose meanings depend on T. 3042** 3043** <dl> 3044** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3045** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3046** first begins running and possibly at other times during the 3047** execution of the prepared statement, such as at the start of each 3048** trigger subprogram. ^The P argument is a pointer to the 3049** [prepared statement]. ^The X argument is a pointer to a string which 3050** is the unexpanded SQL text of the prepared statement or an SQL comment 3051** that indicates the invocation of a trigger. ^The callback can compute 3052** the same text that would have been returned by the legacy [sqlite3_trace()] 3053** interface by using the X argument when X begins with "--" and invoking 3054** [sqlite3_expanded_sql(P)] otherwise. 3055** 3056** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3057** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3058** information as is provided by the [sqlite3_profile()] callback. 3059** ^The P argument is a pointer to the [prepared statement] and the 3060** X argument points to a 64-bit integer which is the estimated of 3061** the number of nanosecond that the prepared statement took to run. 3062** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3063** 3064** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3065** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3066** statement generates a single row of result. 3067** ^The P argument is a pointer to the [prepared statement] and the 3068** X argument is unused. 3069** 3070** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3071** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3072** connection closes. 3073** ^The P argument is a pointer to the [database connection] object 3074** and the X argument is unused. 3075** </dl> 3076*/ 3077#define SQLITE_TRACE_STMT 0x01 3078#define SQLITE_TRACE_PROFILE 0x02 3079#define SQLITE_TRACE_ROW 0x04 3080#define SQLITE_TRACE_CLOSE 0x08 3081 3082/* 3083** CAPI3REF: SQL Trace Hook 3084** METHOD: sqlite3 3085** 3086** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3087** function X against [database connection] D, using property mask M 3088** and context pointer P. ^If the X callback is 3089** NULL or if the M mask is zero, then tracing is disabled. The 3090** M argument should be the bitwise OR-ed combination of 3091** zero or more [SQLITE_TRACE] constants. 3092** 3093** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3094** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3095** 3096** ^The X callback is invoked whenever any of the events identified by 3097** mask M occur. ^The integer return value from the callback is currently 3098** ignored, though this may change in future releases. Callback 3099** implementations should return zero to ensure future compatibility. 3100** 3101** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3102** ^The T argument is one of the [SQLITE_TRACE] 3103** constants to indicate why the callback was invoked. 3104** ^The C argument is a copy of the context pointer. 3105** The P and X arguments are pointers whose meanings depend on T. 3106** 3107** The sqlite3_trace_v2() interface is intended to replace the legacy 3108** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3109** are deprecated. 3110*/ 3111int sqlite3_trace_v2( 3112 sqlite3*, 3113 unsigned uMask, 3114 int(*xCallback)(unsigned,void*,void*,void*), 3115 void *pCtx 3116); 3117 3118/* 3119** CAPI3REF: Query Progress Callbacks 3120** METHOD: sqlite3 3121** 3122** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3123** function X to be invoked periodically during long running calls to 3124** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3125** database connection D. An example use for this 3126** interface is to keep a GUI updated during a large query. 3127** 3128** ^The parameter P is passed through as the only parameter to the 3129** callback function X. ^The parameter N is the approximate number of 3130** [virtual machine instructions] that are evaluated between successive 3131** invocations of the callback X. ^If N is less than one then the progress 3132** handler is disabled. 3133** 3134** ^Only a single progress handler may be defined at one time per 3135** [database connection]; setting a new progress handler cancels the 3136** old one. ^Setting parameter X to NULL disables the progress handler. 3137** ^The progress handler is also disabled by setting N to a value less 3138** than 1. 3139** 3140** ^If the progress callback returns non-zero, the operation is 3141** interrupted. This feature can be used to implement a 3142** "Cancel" button on a GUI progress dialog box. 3143** 3144** The progress handler callback must not do anything that will modify 3145** the database connection that invoked the progress handler. 3146** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3147** database connections for the meaning of "modify" in this paragraph. 3148** 3149*/ 3150void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3151 3152/* 3153** CAPI3REF: Opening A New Database Connection 3154** CONSTRUCTOR: sqlite3 3155** 3156** ^These routines open an SQLite database file as specified by the 3157** filename argument. ^The filename argument is interpreted as UTF-8 for 3158** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3159** order for sqlite3_open16(). ^(A [database connection] handle is usually 3160** returned in *ppDb, even if an error occurs. The only exception is that 3161** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3162** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3163** object.)^ ^(If the database is opened (and/or created) successfully, then 3164** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3165** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3166** an English language description of the error following a failure of any 3167** of the sqlite3_open() routines. 3168** 3169** ^The default encoding will be UTF-8 for databases created using 3170** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3171** created using sqlite3_open16() will be UTF-16 in the native byte order. 3172** 3173** Whether or not an error occurs when it is opened, resources 3174** associated with the [database connection] handle should be released by 3175** passing it to [sqlite3_close()] when it is no longer required. 3176** 3177** The sqlite3_open_v2() interface works like sqlite3_open() 3178** except that it accepts two additional parameters for additional control 3179** over the new database connection. ^(The flags parameter to 3180** sqlite3_open_v2() can take one of 3181** the following three values, optionally combined with the 3182** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3183** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3184** 3185** <dl> 3186** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3187** <dd>The database is opened in read-only mode. If the database does not 3188** already exist, an error is returned.</dd>)^ 3189** 3190** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3191** <dd>The database is opened for reading and writing if possible, or reading 3192** only if the file is write protected by the operating system. In either 3193** case the database must already exist, otherwise an error is returned.</dd>)^ 3194** 3195** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3196** <dd>The database is opened for reading and writing, and is created if 3197** it does not already exist. This is the behavior that is always used for 3198** sqlite3_open() and sqlite3_open16().</dd>)^ 3199** </dl> 3200** 3201** If the 3rd parameter to sqlite3_open_v2() is not one of the 3202** combinations shown above optionally combined with other 3203** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3204** then the behavior is undefined. 3205** 3206** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3207** opens in the multi-thread [threading mode] as long as the single-thread 3208** mode has not been set at compile-time or start-time. ^If the 3209** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3210** in the serialized [threading mode] unless single-thread was 3211** previously selected at compile-time or start-time. 3212** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3213** eligible to use [shared cache mode], regardless of whether or not shared 3214** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3215** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3216** participate in [shared cache mode] even if it is enabled. 3217** 3218** ^The fourth parameter to sqlite3_open_v2() is the name of the 3219** [sqlite3_vfs] object that defines the operating system interface that 3220** the new database connection should use. ^If the fourth parameter is 3221** a NULL pointer then the default [sqlite3_vfs] object is used. 3222** 3223** ^If the filename is ":memory:", then a private, temporary in-memory database 3224** is created for the connection. ^This in-memory database will vanish when 3225** the database connection is closed. Future versions of SQLite might 3226** make use of additional special filenames that begin with the ":" character. 3227** It is recommended that when a database filename actually does begin with 3228** a ":" character you should prefix the filename with a pathname such as 3229** "./" to avoid ambiguity. 3230** 3231** ^If the filename is an empty string, then a private, temporary 3232** on-disk database will be created. ^This private database will be 3233** automatically deleted as soon as the database connection is closed. 3234** 3235** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3236** 3237** ^If [URI filename] interpretation is enabled, and the filename argument 3238** begins with "file:", then the filename is interpreted as a URI. ^URI 3239** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3240** set in the third argument to sqlite3_open_v2(), or if it has 3241** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3242** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3243** URI filename interpretation is turned off 3244** by default, but future releases of SQLite might enable URI filename 3245** interpretation by default. See "[URI filenames]" for additional 3246** information. 3247** 3248** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3249** authority, then it must be either an empty string or the string 3250** "localhost". ^If the authority is not an empty string or "localhost", an 3251** error is returned to the caller. ^The fragment component of a URI, if 3252** present, is ignored. 3253** 3254** ^SQLite uses the path component of the URI as the name of the disk file 3255** which contains the database. ^If the path begins with a '/' character, 3256** then it is interpreted as an absolute path. ^If the path does not begin 3257** with a '/' (meaning that the authority section is omitted from the URI) 3258** then the path is interpreted as a relative path. 3259** ^(On windows, the first component of an absolute path 3260** is a drive specification (e.g. "C:").)^ 3261** 3262** [[core URI query parameters]] 3263** The query component of a URI may contain parameters that are interpreted 3264** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3265** SQLite and its built-in [VFSes] interpret the 3266** following query parameters: 3267** 3268** <ul> 3269** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3270** a VFS object that provides the operating system interface that should 3271** be used to access the database file on disk. ^If this option is set to 3272** an empty string the default VFS object is used. ^Specifying an unknown 3273** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3274** present, then the VFS specified by the option takes precedence over 3275** the value passed as the fourth parameter to sqlite3_open_v2(). 3276** 3277** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3278** "rwc", or "memory". Attempting to set it to any other value is 3279** an error)^. 3280** ^If "ro" is specified, then the database is opened for read-only 3281** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3282** third argument to sqlite3_open_v2(). ^If the mode option is set to 3283** "rw", then the database is opened for read-write (but not create) 3284** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3285** been set. ^Value "rwc" is equivalent to setting both 3286** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3287** set to "memory" then a pure [in-memory database] that never reads 3288** or writes from disk is used. ^It is an error to specify a value for 3289** the mode parameter that is less restrictive than that specified by 3290** the flags passed in the third parameter to sqlite3_open_v2(). 3291** 3292** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3293** "private". ^Setting it to "shared" is equivalent to setting the 3294** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3295** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3296** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3297** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3298** a URI filename, its value overrides any behavior requested by setting 3299** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3300** 3301** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3302** [powersafe overwrite] property does or does not apply to the 3303** storage media on which the database file resides. 3304** 3305** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3306** which if set disables file locking in rollback journal modes. This 3307** is useful for accessing a database on a filesystem that does not 3308** support locking. Caution: Database corruption might result if two 3309** or more processes write to the same database and any one of those 3310** processes uses nolock=1. 3311** 3312** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3313** parameter that indicates that the database file is stored on 3314** read-only media. ^When immutable is set, SQLite assumes that the 3315** database file cannot be changed, even by a process with higher 3316** privilege, and so the database is opened read-only and all locking 3317** and change detection is disabled. Caution: Setting the immutable 3318** property on a database file that does in fact change can result 3319** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3320** See also: [SQLITE_IOCAP_IMMUTABLE]. 3321** 3322** </ul> 3323** 3324** ^Specifying an unknown parameter in the query component of a URI is not an 3325** error. Future versions of SQLite might understand additional query 3326** parameters. See "[query parameters with special meaning to SQLite]" for 3327** additional information. 3328** 3329** [[URI filename examples]] <h3>URI filename examples</h3> 3330** 3331** <table border="1" align=center cellpadding=5> 3332** <tr><th> URI filenames <th> Results 3333** <tr><td> file:data.db <td> 3334** Open the file "data.db" in the current directory. 3335** <tr><td> file:/home/fred/data.db<br> 3336** file:///home/fred/data.db <br> 3337** file://localhost/home/fred/data.db <br> <td> 3338** Open the database file "/home/fred/data.db". 3339** <tr><td> file://darkstar/home/fred/data.db <td> 3340** An error. "darkstar" is not a recognized authority. 3341** <tr><td style="white-space:nowrap"> 3342** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3343** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3344** C:. Note that the %20 escaping in this example is not strictly 3345** necessary - space characters can be used literally 3346** in URI filenames. 3347** <tr><td> file:data.db?mode=ro&cache=private <td> 3348** Open file "data.db" in the current directory for read-only access. 3349** Regardless of whether or not shared-cache mode is enabled by 3350** default, use a private cache. 3351** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3352** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3353** that uses dot-files in place of posix advisory locking. 3354** <tr><td> file:data.db?mode=readonly <td> 3355** An error. "readonly" is not a valid option for the "mode" parameter. 3356** </table> 3357** 3358** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3359** query components of a URI. A hexadecimal escape sequence consists of a 3360** percent sign - "%" - followed by exactly two hexadecimal digits 3361** specifying an octet value. ^Before the path or query components of a 3362** URI filename are interpreted, they are encoded using UTF-8 and all 3363** hexadecimal escape sequences replaced by a single byte containing the 3364** corresponding octet. If this process generates an invalid UTF-8 encoding, 3365** the results are undefined. 3366** 3367** <b>Note to Windows users:</b> The encoding used for the filename argument 3368** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3369** codepage is currently defined. Filenames containing international 3370** characters must be converted to UTF-8 prior to passing them into 3371** sqlite3_open() or sqlite3_open_v2(). 3372** 3373** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3374** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3375** features that require the use of temporary files may fail. 3376** 3377** See also: [sqlite3_temp_directory] 3378*/ 3379int sqlite3_open( 3380 const char *filename, /* Database filename (UTF-8) */ 3381 sqlite3 **ppDb /* OUT: SQLite db handle */ 3382); 3383int sqlite3_open16( 3384 const void *filename, /* Database filename (UTF-16) */ 3385 sqlite3 **ppDb /* OUT: SQLite db handle */ 3386); 3387int sqlite3_open_v2( 3388 const char *filename, /* Database filename (UTF-8) */ 3389 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3390 int flags, /* Flags */ 3391 const char *zVfs /* Name of VFS module to use */ 3392); 3393 3394/* 3395** CAPI3REF: Obtain Values For URI Parameters 3396** 3397** These are utility routines, useful to VFS implementations, that check 3398** to see if a database file was a URI that contained a specific query 3399** parameter, and if so obtains the value of that query parameter. 3400** 3401** If F is the database filename pointer passed into the xOpen() method of 3402** a VFS implementation when the flags parameter to xOpen() has one or 3403** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3404** P is the name of the query parameter, then 3405** sqlite3_uri_parameter(F,P) returns the value of the P 3406** parameter if it exists or a NULL pointer if P does not appear as a 3407** query parameter on F. If P is a query parameter of F 3408** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3409** a pointer to an empty string. 3410** 3411** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3412** parameter and returns true (1) or false (0) according to the value 3413** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3414** value of query parameter P is one of "yes", "true", or "on" in any 3415** case or if the value begins with a non-zero number. The 3416** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3417** query parameter P is one of "no", "false", or "off" in any case or 3418** if the value begins with a numeric zero. If P is not a query 3419** parameter on F or if the value of P is does not match any of the 3420** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3421** 3422** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3423** 64-bit signed integer and returns that integer, or D if P does not 3424** exist. If the value of P is something other than an integer, then 3425** zero is returned. 3426** 3427** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3428** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3429** is not a database file pathname pointer that SQLite passed into the xOpen 3430** VFS method, then the behavior of this routine is undefined and probably 3431** undesirable. 3432** 3433** See the [URI filename] documentation for additional information. 3434*/ 3435const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3436int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3437sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3438 3439 3440/* 3441** CAPI3REF: Error Codes And Messages 3442** METHOD: sqlite3 3443** 3444** ^If the most recent sqlite3_* API call associated with 3445** [database connection] D failed, then the sqlite3_errcode(D) interface 3446** returns the numeric [result code] or [extended result code] for that 3447** API call. 3448** ^The sqlite3_extended_errcode() 3449** interface is the same except that it always returns the 3450** [extended result code] even when extended result codes are 3451** disabled. 3452** 3453** The values returned by sqlite3_errcode() and/or 3454** sqlite3_extended_errcode() might change with each API call. 3455** Except, there are some interfaces that are guaranteed to never 3456** change the value of the error code. The error-code preserving 3457** interfaces are: 3458** 3459** <ul> 3460** <li> sqlite3_errcode() 3461** <li> sqlite3_extended_errcode() 3462** <li> sqlite3_errmsg() 3463** <li> sqlite3_errmsg16() 3464** </ul> 3465** 3466** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3467** text that describes the error, as either UTF-8 or UTF-16 respectively. 3468** ^(Memory to hold the error message string is managed internally. 3469** The application does not need to worry about freeing the result. 3470** However, the error string might be overwritten or deallocated by 3471** subsequent calls to other SQLite interface functions.)^ 3472** 3473** ^The sqlite3_errstr() interface returns the English-language text 3474** that describes the [result code], as UTF-8. 3475** ^(Memory to hold the error message string is managed internally 3476** and must not be freed by the application)^. 3477** 3478** When the serialized [threading mode] is in use, it might be the 3479** case that a second error occurs on a separate thread in between 3480** the time of the first error and the call to these interfaces. 3481** When that happens, the second error will be reported since these 3482** interfaces always report the most recent result. To avoid 3483** this, each thread can obtain exclusive use of the [database connection] D 3484** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3485** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3486** all calls to the interfaces listed here are completed. 3487** 3488** If an interface fails with SQLITE_MISUSE, that means the interface 3489** was invoked incorrectly by the application. In that case, the 3490** error code and message may or may not be set. 3491*/ 3492int sqlite3_errcode(sqlite3 *db); 3493int sqlite3_extended_errcode(sqlite3 *db); 3494const char *sqlite3_errmsg(sqlite3*); 3495const void *sqlite3_errmsg16(sqlite3*); 3496const char *sqlite3_errstr(int); 3497 3498/* 3499** CAPI3REF: Prepared Statement Object 3500** KEYWORDS: {prepared statement} {prepared statements} 3501** 3502** An instance of this object represents a single SQL statement that 3503** has been compiled into binary form and is ready to be evaluated. 3504** 3505** Think of each SQL statement as a separate computer program. The 3506** original SQL text is source code. A prepared statement object 3507** is the compiled object code. All SQL must be converted into a 3508** prepared statement before it can be run. 3509** 3510** The life-cycle of a prepared statement object usually goes like this: 3511** 3512** <ol> 3513** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3514** <li> Bind values to [parameters] using the sqlite3_bind_*() 3515** interfaces. 3516** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3517** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3518** to step 2. Do this zero or more times. 3519** <li> Destroy the object using [sqlite3_finalize()]. 3520** </ol> 3521*/ 3522typedef struct sqlite3_stmt sqlite3_stmt; 3523 3524/* 3525** CAPI3REF: Run-time Limits 3526** METHOD: sqlite3 3527** 3528** ^(This interface allows the size of various constructs to be limited 3529** on a connection by connection basis. The first parameter is the 3530** [database connection] whose limit is to be set or queried. The 3531** second parameter is one of the [limit categories] that define a 3532** class of constructs to be size limited. The third parameter is the 3533** new limit for that construct.)^ 3534** 3535** ^If the new limit is a negative number, the limit is unchanged. 3536** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3537** [limits | hard upper bound] 3538** set at compile-time by a C preprocessor macro called 3539** [limits | SQLITE_MAX_<i>NAME</i>]. 3540** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3541** ^Attempts to increase a limit above its hard upper bound are 3542** silently truncated to the hard upper bound. 3543** 3544** ^Regardless of whether or not the limit was changed, the 3545** [sqlite3_limit()] interface returns the prior value of the limit. 3546** ^Hence, to find the current value of a limit without changing it, 3547** simply invoke this interface with the third parameter set to -1. 3548** 3549** Run-time limits are intended for use in applications that manage 3550** both their own internal database and also databases that are controlled 3551** by untrusted external sources. An example application might be a 3552** web browser that has its own databases for storing history and 3553** separate databases controlled by JavaScript applications downloaded 3554** off the Internet. The internal databases can be given the 3555** large, default limits. Databases managed by external sources can 3556** be given much smaller limits designed to prevent a denial of service 3557** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3558** interface to further control untrusted SQL. The size of the database 3559** created by an untrusted script can be contained using the 3560** [max_page_count] [PRAGMA]. 3561** 3562** New run-time limit categories may be added in future releases. 3563*/ 3564int sqlite3_limit(sqlite3*, int id, int newVal); 3565 3566/* 3567** CAPI3REF: Run-Time Limit Categories 3568** KEYWORDS: {limit category} {*limit categories} 3569** 3570** These constants define various performance limits 3571** that can be lowered at run-time using [sqlite3_limit()]. 3572** The synopsis of the meanings of the various limits is shown below. 3573** Additional information is available at [limits | Limits in SQLite]. 3574** 3575** <dl> 3576** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3577** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3578** 3579** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3580** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3581** 3582** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3583** <dd>The maximum number of columns in a table definition or in the 3584** result set of a [SELECT] or the maximum number of columns in an index 3585** or in an ORDER BY or GROUP BY clause.</dd>)^ 3586** 3587** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3588** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3589** 3590** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3591** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3592** 3593** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3594** <dd>The maximum number of instructions in a virtual machine program 3595** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3596** the equivalent tries to allocate space for more than this many opcodes 3597** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3598** 3599** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3600** <dd>The maximum number of arguments on a function.</dd>)^ 3601** 3602** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3603** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3604** 3605** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3606** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3607** <dd>The maximum length of the pattern argument to the [LIKE] or 3608** [GLOB] operators.</dd>)^ 3609** 3610** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3611** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3612** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3613** 3614** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3615** <dd>The maximum depth of recursion for triggers.</dd>)^ 3616** 3617** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3618** <dd>The maximum number of auxiliary worker threads that a single 3619** [prepared statement] may start.</dd>)^ 3620** </dl> 3621*/ 3622#define SQLITE_LIMIT_LENGTH 0 3623#define SQLITE_LIMIT_SQL_LENGTH 1 3624#define SQLITE_LIMIT_COLUMN 2 3625#define SQLITE_LIMIT_EXPR_DEPTH 3 3626#define SQLITE_LIMIT_COMPOUND_SELECT 4 3627#define SQLITE_LIMIT_VDBE_OP 5 3628#define SQLITE_LIMIT_FUNCTION_ARG 6 3629#define SQLITE_LIMIT_ATTACHED 7 3630#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3631#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3632#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3633#define SQLITE_LIMIT_WORKER_THREADS 11 3634 3635/* 3636** CAPI3REF: Prepare Flags 3637** 3638** These constants define various flags that can be passed into 3639** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3640** [sqlite3_prepare16_v3()] interfaces. 3641** 3642** New flags may be added in future releases of SQLite. 3643** 3644** <dl> 3645** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3646** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3647** that the prepared statement will be retained for a long time and 3648** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3649** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3650** be used just once or at most a few times and then destroyed using 3651** [sqlite3_finalize()] relatively soon. The current implementation acts 3652** on this hint by avoiding the use of [lookaside memory] so as not to 3653** deplete the limited store of lookaside memory. Future versions of 3654** SQLite may act on this hint differently. 3655** 3656** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3657** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3658** to be required for any prepared statement that wanted to use the 3659** [sqlite3_normalized_sql()] interface. However, the 3660** [sqlite3_normalized_sql()] interface is now available to all 3661** prepared statements, regardless of whether or not they use this 3662** flag. 3663** 3664** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3665** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3666** to return an error (error code SQLITE_ERROR) if the statement uses 3667** any virtual tables. 3668** </dl> 3669*/ 3670#define SQLITE_PREPARE_PERSISTENT 0x01 3671#define SQLITE_PREPARE_NORMALIZE 0x02 3672#define SQLITE_PREPARE_NO_VTAB 0x04 3673 3674/* 3675** CAPI3REF: Compiling An SQL Statement 3676** KEYWORDS: {SQL statement compiler} 3677** METHOD: sqlite3 3678** CONSTRUCTOR: sqlite3_stmt 3679** 3680** To execute an SQL statement, it must first be compiled into a byte-code 3681** program using one of these routines. Or, in other words, these routines 3682** are constructors for the [prepared statement] object. 3683** 3684** The preferred routine to use is [sqlite3_prepare_v2()]. The 3685** [sqlite3_prepare()] interface is legacy and should be avoided. 3686** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3687** for special purposes. 3688** 3689** The use of the UTF-8 interfaces is preferred, as SQLite currently 3690** does all parsing using UTF-8. The UTF-16 interfaces are provided 3691** as a convenience. The UTF-16 interfaces work by converting the 3692** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3693** 3694** The first argument, "db", is a [database connection] obtained from a 3695** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3696** [sqlite3_open16()]. The database connection must not have been closed. 3697** 3698** The second argument, "zSql", is the statement to be compiled, encoded 3699** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3700** and sqlite3_prepare_v3() 3701** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3702** and sqlite3_prepare16_v3() use UTF-16. 3703** 3704** ^If the nByte argument is negative, then zSql is read up to the 3705** first zero terminator. ^If nByte is positive, then it is the 3706** number of bytes read from zSql. ^If nByte is zero, then no prepared 3707** statement is generated. 3708** If the caller knows that the supplied string is nul-terminated, then 3709** there is a small performance advantage to passing an nByte parameter that 3710** is the number of bytes in the input string <i>including</i> 3711** the nul-terminator. 3712** 3713** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3714** past the end of the first SQL statement in zSql. These routines only 3715** compile the first statement in zSql, so *pzTail is left pointing to 3716** what remains uncompiled. 3717** 3718** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3719** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3720** to NULL. ^If the input text contains no SQL (if the input is an empty 3721** string or a comment) then *ppStmt is set to NULL. 3722** The calling procedure is responsible for deleting the compiled 3723** SQL statement using [sqlite3_finalize()] after it has finished with it. 3724** ppStmt may not be NULL. 3725** 3726** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3727** otherwise an [error code] is returned. 3728** 3729** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3730** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3731** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3732** are retained for backwards compatibility, but their use is discouraged. 3733** ^In the "vX" interfaces, the prepared statement 3734** that is returned (the [sqlite3_stmt] object) contains a copy of the 3735** original SQL text. This causes the [sqlite3_step()] interface to 3736** behave differently in three ways: 3737** 3738** <ol> 3739** <li> 3740** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3741** always used to do, [sqlite3_step()] will automatically recompile the SQL 3742** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3743** retries will occur before sqlite3_step() gives up and returns an error. 3744** </li> 3745** 3746** <li> 3747** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3748** [error codes] or [extended error codes]. ^The legacy behavior was that 3749** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3750** and the application would have to make a second call to [sqlite3_reset()] 3751** in order to find the underlying cause of the problem. With the "v2" prepare 3752** interfaces, the underlying reason for the error is returned immediately. 3753** </li> 3754** 3755** <li> 3756** ^If the specific value bound to [parameter | host parameter] in the 3757** WHERE clause might influence the choice of query plan for a statement, 3758** then the statement will be automatically recompiled, as if there had been 3759** a schema change, on the first [sqlite3_step()] call following any change 3760** to the [sqlite3_bind_text | bindings] of that [parameter]. 3761** ^The specific value of WHERE-clause [parameter] might influence the 3762** choice of query plan if the parameter is the left-hand side of a [LIKE] 3763** or [GLOB] operator or if the parameter is compared to an indexed column 3764** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 3765** </li> 3766** </ol> 3767** 3768** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3769** the extra prepFlags parameter, which is a bit array consisting of zero or 3770** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3771** sqlite3_prepare_v2() interface works exactly the same as 3772** sqlite3_prepare_v3() with a zero prepFlags parameter. 3773*/ 3774int sqlite3_prepare( 3775 sqlite3 *db, /* Database handle */ 3776 const char *zSql, /* SQL statement, UTF-8 encoded */ 3777 int nByte, /* Maximum length of zSql in bytes. */ 3778 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3779 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3780); 3781int sqlite3_prepare_v2( 3782 sqlite3 *db, /* Database handle */ 3783 const char *zSql, /* SQL statement, UTF-8 encoded */ 3784 int nByte, /* Maximum length of zSql in bytes. */ 3785 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3786 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3787); 3788int sqlite3_prepare_v3( 3789 sqlite3 *db, /* Database handle */ 3790 const char *zSql, /* SQL statement, UTF-8 encoded */ 3791 int nByte, /* Maximum length of zSql in bytes. */ 3792 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3793 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3794 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3795); 3796int sqlite3_prepare16( 3797 sqlite3 *db, /* Database handle */ 3798 const void *zSql, /* SQL statement, UTF-16 encoded */ 3799 int nByte, /* Maximum length of zSql in bytes. */ 3800 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3801 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3802); 3803int sqlite3_prepare16_v2( 3804 sqlite3 *db, /* Database handle */ 3805 const void *zSql, /* SQL statement, UTF-16 encoded */ 3806 int nByte, /* Maximum length of zSql in bytes. */ 3807 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3808 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3809); 3810int sqlite3_prepare16_v3( 3811 sqlite3 *db, /* Database handle */ 3812 const void *zSql, /* SQL statement, UTF-16 encoded */ 3813 int nByte, /* Maximum length of zSql in bytes. */ 3814 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3815 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3816 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3817); 3818 3819/* 3820** CAPI3REF: Retrieving Statement SQL 3821** METHOD: sqlite3_stmt 3822** 3823** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3824** SQL text used to create [prepared statement] P if P was 3825** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3826** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3827** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3828** string containing the SQL text of prepared statement P with 3829** [bound parameters] expanded. 3830** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 3831** string containing the normalized SQL text of prepared statement P. The 3832** semantics used to normalize a SQL statement are unspecified and subject 3833** to change. At a minimum, literal values will be replaced with suitable 3834** placeholders. 3835** 3836** ^(For example, if a prepared statement is created using the SQL 3837** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3838** and parameter :xyz is unbound, then sqlite3_sql() will return 3839** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3840** will return "SELECT 2345,NULL".)^ 3841** 3842** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3843** is available to hold the result, or if the result would exceed the 3844** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3845** 3846** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3847** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3848** option causes sqlite3_expanded_sql() to always return NULL. 3849** 3850** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 3851** are managed by SQLite and are automatically freed when the prepared 3852** statement is finalized. 3853** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3854** is obtained from [sqlite3_malloc()] and must be free by the application 3855** by passing it to [sqlite3_free()]. 3856*/ 3857const char *sqlite3_sql(sqlite3_stmt *pStmt); 3858char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3859const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 3860 3861/* 3862** CAPI3REF: Determine If An SQL Statement Writes The Database 3863** METHOD: sqlite3_stmt 3864** 3865** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3866** and only if the [prepared statement] X makes no direct changes to 3867** the content of the database file. 3868** 3869** Note that [application-defined SQL functions] or 3870** [virtual tables] might change the database indirectly as a side effect. 3871** ^(For example, if an application defines a function "eval()" that 3872** calls [sqlite3_exec()], then the following SQL statement would 3873** change the database file through side-effects: 3874** 3875** <blockquote><pre> 3876** SELECT eval('DELETE FROM t1') FROM t2; 3877** </pre></blockquote> 3878** 3879** But because the [SELECT] statement does not change the database file 3880** directly, sqlite3_stmt_readonly() would still return true.)^ 3881** 3882** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3883** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3884** since the statements themselves do not actually modify the database but 3885** rather they control the timing of when other statements modify the 3886** database. ^The [ATTACH] and [DETACH] statements also cause 3887** sqlite3_stmt_readonly() to return true since, while those statements 3888** change the configuration of a database connection, they do not make 3889** changes to the content of the database files on disk. 3890** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3891** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3892** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3893** sqlite3_stmt_readonly() returns false for those commands. 3894*/ 3895int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3896 3897/* 3898** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 3899** METHOD: sqlite3_stmt 3900** 3901** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 3902** prepared statement S is an EXPLAIN statement, or 2 if the 3903** statement S is an EXPLAIN QUERY PLAN. 3904** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 3905** an ordinary statement or a NULL pointer. 3906*/ 3907int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 3908 3909/* 3910** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3911** METHOD: sqlite3_stmt 3912** 3913** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3914** [prepared statement] S has been stepped at least once using 3915** [sqlite3_step(S)] but has neither run to completion (returned 3916** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3917** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3918** interface returns false if S is a NULL pointer. If S is not a 3919** NULL pointer and is not a pointer to a valid [prepared statement] 3920** object, then the behavior is undefined and probably undesirable. 3921** 3922** This interface can be used in combination [sqlite3_next_stmt()] 3923** to locate all prepared statements associated with a database 3924** connection that are in need of being reset. This can be used, 3925** for example, in diagnostic routines to search for prepared 3926** statements that are holding a transaction open. 3927*/ 3928int sqlite3_stmt_busy(sqlite3_stmt*); 3929 3930/* 3931** CAPI3REF: Dynamically Typed Value Object 3932** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3933** 3934** SQLite uses the sqlite3_value object to represent all values 3935** that can be stored in a database table. SQLite uses dynamic typing 3936** for the values it stores. ^Values stored in sqlite3_value objects 3937** can be integers, floating point values, strings, BLOBs, or NULL. 3938** 3939** An sqlite3_value object may be either "protected" or "unprotected". 3940** Some interfaces require a protected sqlite3_value. Other interfaces 3941** will accept either a protected or an unprotected sqlite3_value. 3942** Every interface that accepts sqlite3_value arguments specifies 3943** whether or not it requires a protected sqlite3_value. The 3944** [sqlite3_value_dup()] interface can be used to construct a new 3945** protected sqlite3_value from an unprotected sqlite3_value. 3946** 3947** The terms "protected" and "unprotected" refer to whether or not 3948** a mutex is held. An internal mutex is held for a protected 3949** sqlite3_value object but no mutex is held for an unprotected 3950** sqlite3_value object. If SQLite is compiled to be single-threaded 3951** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3952** or if SQLite is run in one of reduced mutex modes 3953** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3954** then there is no distinction between protected and unprotected 3955** sqlite3_value objects and they can be used interchangeably. However, 3956** for maximum code portability it is recommended that applications 3957** still make the distinction between protected and unprotected 3958** sqlite3_value objects even when not strictly required. 3959** 3960** ^The sqlite3_value objects that are passed as parameters into the 3961** implementation of [application-defined SQL functions] are protected. 3962** ^The sqlite3_value object returned by 3963** [sqlite3_column_value()] is unprotected. 3964** Unprotected sqlite3_value objects may only be used as arguments 3965** to [sqlite3_result_value()], [sqlite3_bind_value()], and 3966** [sqlite3_value_dup()]. 3967** The [sqlite3_value_blob | sqlite3_value_type()] family of 3968** interfaces require protected sqlite3_value objects. 3969*/ 3970typedef struct sqlite3_value sqlite3_value; 3971 3972/* 3973** CAPI3REF: SQL Function Context Object 3974** 3975** The context in which an SQL function executes is stored in an 3976** sqlite3_context object. ^A pointer to an sqlite3_context object 3977** is always first parameter to [application-defined SQL functions]. 3978** The application-defined SQL function implementation will pass this 3979** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3980** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3981** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3982** and/or [sqlite3_set_auxdata()]. 3983*/ 3984typedef struct sqlite3_context sqlite3_context; 3985 3986/* 3987** CAPI3REF: Binding Values To Prepared Statements 3988** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3989** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3990** METHOD: sqlite3_stmt 3991** 3992** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3993** literals may be replaced by a [parameter] that matches one of following 3994** templates: 3995** 3996** <ul> 3997** <li> ? 3998** <li> ?NNN 3999** <li> :VVV 4000** <li> @VVV 4001** <li> $VVV 4002** </ul> 4003** 4004** In the templates above, NNN represents an integer literal, 4005** and VVV represents an alphanumeric identifier.)^ ^The values of these 4006** parameters (also called "host parameter names" or "SQL parameters") 4007** can be set using the sqlite3_bind_*() routines defined here. 4008** 4009** ^The first argument to the sqlite3_bind_*() routines is always 4010** a pointer to the [sqlite3_stmt] object returned from 4011** [sqlite3_prepare_v2()] or its variants. 4012** 4013** ^The second argument is the index of the SQL parameter to be set. 4014** ^The leftmost SQL parameter has an index of 1. ^When the same named 4015** SQL parameter is used more than once, second and subsequent 4016** occurrences have the same index as the first occurrence. 4017** ^The index for named parameters can be looked up using the 4018** [sqlite3_bind_parameter_index()] API if desired. ^The index 4019** for "?NNN" parameters is the value of NNN. 4020** ^The NNN value must be between 1 and the [sqlite3_limit()] 4021** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 4022** 4023** ^The third argument is the value to bind to the parameter. 4024** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4025** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4026** is ignored and the end result is the same as sqlite3_bind_null(). 4027** 4028** ^(In those routines that have a fourth argument, its value is the 4029** number of bytes in the parameter. To be clear: the value is the 4030** number of <u>bytes</u> in the value, not the number of characters.)^ 4031** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4032** is negative, then the length of the string is 4033** the number of bytes up to the first zero terminator. 4034** If the fourth parameter to sqlite3_bind_blob() is negative, then 4035** the behavior is undefined. 4036** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4037** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4038** that parameter must be the byte offset 4039** where the NUL terminator would occur assuming the string were NUL 4040** terminated. If any NUL characters occur at byte offsets less than 4041** the value of the fourth parameter then the resulting string value will 4042** contain embedded NULs. The result of expressions involving strings 4043** with embedded NULs is undefined. 4044** 4045** ^The fifth argument to the BLOB and string binding interfaces 4046** is a destructor used to dispose of the BLOB or 4047** string after SQLite has finished with it. ^The destructor is called 4048** to dispose of the BLOB or string even if the call to the bind API fails, 4049** except the destructor is not called if the third parameter is a NULL 4050** pointer or the fourth parameter is negative. 4051** ^If the fifth argument is 4052** the special value [SQLITE_STATIC], then SQLite assumes that the 4053** information is in static, unmanaged space and does not need to be freed. 4054** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4055** SQLite makes its own private copy of the data immediately, before 4056** the sqlite3_bind_*() routine returns. 4057** 4058** ^The sixth argument to sqlite3_bind_text64() must be one of 4059** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4060** to specify the encoding of the text in the third parameter. If 4061** the sixth argument to sqlite3_bind_text64() is not one of the 4062** allowed values shown above, or if the text encoding is different 4063** from the encoding specified by the sixth parameter, then the behavior 4064** is undefined. 4065** 4066** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4067** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4068** (just an integer to hold its size) while it is being processed. 4069** Zeroblobs are intended to serve as placeholders for BLOBs whose 4070** content is later written using 4071** [sqlite3_blob_open | incremental BLOB I/O] routines. 4072** ^A negative value for the zeroblob results in a zero-length BLOB. 4073** 4074** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4075** [prepared statement] S to have an SQL value of NULL, but to also be 4076** associated with the pointer P of type T. ^D is either a NULL pointer or 4077** a pointer to a destructor function for P. ^SQLite will invoke the 4078** destructor D with a single argument of P when it is finished using 4079** P. The T parameter should be a static string, preferably a string 4080** literal. The sqlite3_bind_pointer() routine is part of the 4081** [pointer passing interface] added for SQLite 3.20.0. 4082** 4083** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4084** for the [prepared statement] or with a prepared statement for which 4085** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4086** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4087** routine is passed a [prepared statement] that has been finalized, the 4088** result is undefined and probably harmful. 4089** 4090** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4091** ^Unbound parameters are interpreted as NULL. 4092** 4093** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4094** [error code] if anything goes wrong. 4095** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4096** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4097** [SQLITE_MAX_LENGTH]. 4098** ^[SQLITE_RANGE] is returned if the parameter 4099** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4100** 4101** See also: [sqlite3_bind_parameter_count()], 4102** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4103*/ 4104int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4105int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4106 void(*)(void*)); 4107int sqlite3_bind_double(sqlite3_stmt*, int, double); 4108int sqlite3_bind_int(sqlite3_stmt*, int, int); 4109int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4110int sqlite3_bind_null(sqlite3_stmt*, int); 4111int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4112int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4113int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4114 void(*)(void*), unsigned char encoding); 4115int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4116int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4117int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4118int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4119 4120/* 4121** CAPI3REF: Number Of SQL Parameters 4122** METHOD: sqlite3_stmt 4123** 4124** ^This routine can be used to find the number of [SQL parameters] 4125** in a [prepared statement]. SQL parameters are tokens of the 4126** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4127** placeholders for values that are [sqlite3_bind_blob | bound] 4128** to the parameters at a later time. 4129** 4130** ^(This routine actually returns the index of the largest (rightmost) 4131** parameter. For all forms except ?NNN, this will correspond to the 4132** number of unique parameters. If parameters of the ?NNN form are used, 4133** there may be gaps in the list.)^ 4134** 4135** See also: [sqlite3_bind_blob|sqlite3_bind()], 4136** [sqlite3_bind_parameter_name()], and 4137** [sqlite3_bind_parameter_index()]. 4138*/ 4139int sqlite3_bind_parameter_count(sqlite3_stmt*); 4140 4141/* 4142** CAPI3REF: Name Of A Host Parameter 4143** METHOD: sqlite3_stmt 4144** 4145** ^The sqlite3_bind_parameter_name(P,N) interface returns 4146** the name of the N-th [SQL parameter] in the [prepared statement] P. 4147** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4148** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4149** respectively. 4150** In other words, the initial ":" or "$" or "@" or "?" 4151** is included as part of the name.)^ 4152** ^Parameters of the form "?" without a following integer have no name 4153** and are referred to as "nameless" or "anonymous parameters". 4154** 4155** ^The first host parameter has an index of 1, not 0. 4156** 4157** ^If the value N is out of range or if the N-th parameter is 4158** nameless, then NULL is returned. ^The returned string is 4159** always in UTF-8 encoding even if the named parameter was 4160** originally specified as UTF-16 in [sqlite3_prepare16()], 4161** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4162** 4163** See also: [sqlite3_bind_blob|sqlite3_bind()], 4164** [sqlite3_bind_parameter_count()], and 4165** [sqlite3_bind_parameter_index()]. 4166*/ 4167const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4168 4169/* 4170** CAPI3REF: Index Of A Parameter With A Given Name 4171** METHOD: sqlite3_stmt 4172** 4173** ^Return the index of an SQL parameter given its name. ^The 4174** index value returned is suitable for use as the second 4175** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4176** is returned if no matching parameter is found. ^The parameter 4177** name must be given in UTF-8 even if the original statement 4178** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4179** [sqlite3_prepare16_v3()]. 4180** 4181** See also: [sqlite3_bind_blob|sqlite3_bind()], 4182** [sqlite3_bind_parameter_count()], and 4183** [sqlite3_bind_parameter_name()]. 4184*/ 4185int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4186 4187/* 4188** CAPI3REF: Reset All Bindings On A Prepared Statement 4189** METHOD: sqlite3_stmt 4190** 4191** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4192** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4193** ^Use this routine to reset all host parameters to NULL. 4194*/ 4195int sqlite3_clear_bindings(sqlite3_stmt*); 4196 4197/* 4198** CAPI3REF: Number Of Columns In A Result Set 4199** METHOD: sqlite3_stmt 4200** 4201** ^Return the number of columns in the result set returned by the 4202** [prepared statement]. ^If this routine returns 0, that means the 4203** [prepared statement] returns no data (for example an [UPDATE]). 4204** ^However, just because this routine returns a positive number does not 4205** mean that one or more rows of data will be returned. ^A SELECT statement 4206** will always have a positive sqlite3_column_count() but depending on the 4207** WHERE clause constraints and the table content, it might return no rows. 4208** 4209** See also: [sqlite3_data_count()] 4210*/ 4211int sqlite3_column_count(sqlite3_stmt *pStmt); 4212 4213/* 4214** CAPI3REF: Column Names In A Result Set 4215** METHOD: sqlite3_stmt 4216** 4217** ^These routines return the name assigned to a particular column 4218** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4219** interface returns a pointer to a zero-terminated UTF-8 string 4220** and sqlite3_column_name16() returns a pointer to a zero-terminated 4221** UTF-16 string. ^The first parameter is the [prepared statement] 4222** that implements the [SELECT] statement. ^The second parameter is the 4223** column number. ^The leftmost column is number 0. 4224** 4225** ^The returned string pointer is valid until either the [prepared statement] 4226** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4227** reprepared by the first call to [sqlite3_step()] for a particular run 4228** or until the next call to 4229** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4230** 4231** ^If sqlite3_malloc() fails during the processing of either routine 4232** (for example during a conversion from UTF-8 to UTF-16) then a 4233** NULL pointer is returned. 4234** 4235** ^The name of a result column is the value of the "AS" clause for 4236** that column, if there is an AS clause. If there is no AS clause 4237** then the name of the column is unspecified and may change from 4238** one release of SQLite to the next. 4239*/ 4240const char *sqlite3_column_name(sqlite3_stmt*, int N); 4241const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4242 4243/* 4244** CAPI3REF: Source Of Data In A Query Result 4245** METHOD: sqlite3_stmt 4246** 4247** ^These routines provide a means to determine the database, table, and 4248** table column that is the origin of a particular result column in 4249** [SELECT] statement. 4250** ^The name of the database or table or column can be returned as 4251** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4252** the database name, the _table_ routines return the table name, and 4253** the origin_ routines return the column name. 4254** ^The returned string is valid until the [prepared statement] is destroyed 4255** using [sqlite3_finalize()] or until the statement is automatically 4256** reprepared by the first call to [sqlite3_step()] for a particular run 4257** or until the same information is requested 4258** again in a different encoding. 4259** 4260** ^The names returned are the original un-aliased names of the 4261** database, table, and column. 4262** 4263** ^The first argument to these interfaces is a [prepared statement]. 4264** ^These functions return information about the Nth result column returned by 4265** the statement, where N is the second function argument. 4266** ^The left-most column is column 0 for these routines. 4267** 4268** ^If the Nth column returned by the statement is an expression or 4269** subquery and is not a column value, then all of these functions return 4270** NULL. ^These routine might also return NULL if a memory allocation error 4271** occurs. ^Otherwise, they return the name of the attached database, table, 4272** or column that query result column was extracted from. 4273** 4274** ^As with all other SQLite APIs, those whose names end with "16" return 4275** UTF-16 encoded strings and the other functions return UTF-8. 4276** 4277** ^These APIs are only available if the library was compiled with the 4278** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4279** 4280** If two or more threads call one or more of these routines against the same 4281** prepared statement and column at the same time then the results are 4282** undefined. 4283** 4284** If two or more threads call one or more 4285** [sqlite3_column_database_name | column metadata interfaces] 4286** for the same [prepared statement] and result column 4287** at the same time then the results are undefined. 4288*/ 4289const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4290const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4291const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4292const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4293const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4294const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4295 4296/* 4297** CAPI3REF: Declared Datatype Of A Query Result 4298** METHOD: sqlite3_stmt 4299** 4300** ^(The first parameter is a [prepared statement]. 4301** If this statement is a [SELECT] statement and the Nth column of the 4302** returned result set of that [SELECT] is a table column (not an 4303** expression or subquery) then the declared type of the table 4304** column is returned.)^ ^If the Nth column of the result set is an 4305** expression or subquery, then a NULL pointer is returned. 4306** ^The returned string is always UTF-8 encoded. 4307** 4308** ^(For example, given the database schema: 4309** 4310** CREATE TABLE t1(c1 VARIANT); 4311** 4312** and the following statement to be compiled: 4313** 4314** SELECT c1 + 1, c1 FROM t1; 4315** 4316** this routine would return the string "VARIANT" for the second result 4317** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4318** 4319** ^SQLite uses dynamic run-time typing. ^So just because a column 4320** is declared to contain a particular type does not mean that the 4321** data stored in that column is of the declared type. SQLite is 4322** strongly typed, but the typing is dynamic not static. ^Type 4323** is associated with individual values, not with the containers 4324** used to hold those values. 4325*/ 4326const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4327const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4328 4329/* 4330** CAPI3REF: Evaluate An SQL Statement 4331** METHOD: sqlite3_stmt 4332** 4333** After a [prepared statement] has been prepared using any of 4334** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4335** or [sqlite3_prepare16_v3()] or one of the legacy 4336** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4337** must be called one or more times to evaluate the statement. 4338** 4339** The details of the behavior of the sqlite3_step() interface depend 4340** on whether the statement was prepared using the newer "vX" interfaces 4341** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4342** [sqlite3_prepare16_v2()] or the older legacy 4343** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4344** new "vX" interface is recommended for new applications but the legacy 4345** interface will continue to be supported. 4346** 4347** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4348** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4349** ^With the "v2" interface, any of the other [result codes] or 4350** [extended result codes] might be returned as well. 4351** 4352** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4353** database locks it needs to do its job. ^If the statement is a [COMMIT] 4354** or occurs outside of an explicit transaction, then you can retry the 4355** statement. If the statement is not a [COMMIT] and occurs within an 4356** explicit transaction then you should rollback the transaction before 4357** continuing. 4358** 4359** ^[SQLITE_DONE] means that the statement has finished executing 4360** successfully. sqlite3_step() should not be called again on this virtual 4361** machine without first calling [sqlite3_reset()] to reset the virtual 4362** machine back to its initial state. 4363** 4364** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4365** is returned each time a new row of data is ready for processing by the 4366** caller. The values may be accessed using the [column access functions]. 4367** sqlite3_step() is called again to retrieve the next row of data. 4368** 4369** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4370** violation) has occurred. sqlite3_step() should not be called again on 4371** the VM. More information may be found by calling [sqlite3_errmsg()]. 4372** ^With the legacy interface, a more specific error code (for example, 4373** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4374** can be obtained by calling [sqlite3_reset()] on the 4375** [prepared statement]. ^In the "v2" interface, 4376** the more specific error code is returned directly by sqlite3_step(). 4377** 4378** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4379** Perhaps it was called on a [prepared statement] that has 4380** already been [sqlite3_finalize | finalized] or on one that had 4381** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4382** be the case that the same database connection is being used by two or 4383** more threads at the same moment in time. 4384** 4385** For all versions of SQLite up to and including 3.6.23.1, a call to 4386** [sqlite3_reset()] was required after sqlite3_step() returned anything 4387** other than [SQLITE_ROW] before any subsequent invocation of 4388** sqlite3_step(). Failure to reset the prepared statement using 4389** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4390** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4391** sqlite3_step() began 4392** calling [sqlite3_reset()] automatically in this circumstance rather 4393** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4394** break because any application that ever receives an SQLITE_MISUSE error 4395** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4396** can be used to restore the legacy behavior. 4397** 4398** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4399** API always returns a generic error code, [SQLITE_ERROR], following any 4400** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4401** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4402** specific [error codes] that better describes the error. 4403** We admit that this is a goofy design. The problem has been fixed 4404** with the "v2" interface. If you prepare all of your SQL statements 4405** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4406** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4407** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4408** then the more specific [error codes] are returned directly 4409** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4410*/ 4411int sqlite3_step(sqlite3_stmt*); 4412 4413/* 4414** CAPI3REF: Number of columns in a result set 4415** METHOD: sqlite3_stmt 4416** 4417** ^The sqlite3_data_count(P) interface returns the number of columns in the 4418** current row of the result set of [prepared statement] P. 4419** ^If prepared statement P does not have results ready to return 4420** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4421** interfaces) then sqlite3_data_count(P) returns 0. 4422** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4423** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4424** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4425** will return non-zero if previous call to [sqlite3_step](P) returned 4426** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4427** where it always returns zero since each step of that multi-step 4428** pragma returns 0 columns of data. 4429** 4430** See also: [sqlite3_column_count()] 4431*/ 4432int sqlite3_data_count(sqlite3_stmt *pStmt); 4433 4434/* 4435** CAPI3REF: Fundamental Datatypes 4436** KEYWORDS: SQLITE_TEXT 4437** 4438** ^(Every value in SQLite has one of five fundamental datatypes: 4439** 4440** <ul> 4441** <li> 64-bit signed integer 4442** <li> 64-bit IEEE floating point number 4443** <li> string 4444** <li> BLOB 4445** <li> NULL 4446** </ul>)^ 4447** 4448** These constants are codes for each of those types. 4449** 4450** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4451** for a completely different meaning. Software that links against both 4452** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4453** SQLITE_TEXT. 4454*/ 4455#define SQLITE_INTEGER 1 4456#define SQLITE_FLOAT 2 4457#define SQLITE_BLOB 4 4458#define SQLITE_NULL 5 4459#ifdef SQLITE_TEXT 4460# undef SQLITE_TEXT 4461#else 4462# define SQLITE_TEXT 3 4463#endif 4464#define SQLITE3_TEXT 3 4465 4466/* 4467** CAPI3REF: Result Values From A Query 4468** KEYWORDS: {column access functions} 4469** METHOD: sqlite3_stmt 4470** 4471** <b>Summary:</b> 4472** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4473** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4474** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4475** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4476** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4477** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4478** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4479** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4480** [sqlite3_value|unprotected sqlite3_value] object. 4481** <tr><td> <td> <td> 4482** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4483** or a UTF-8 TEXT result in bytes 4484** <tr><td><b>sqlite3_column_bytes16 </b> 4485** <td>→ <td>Size of UTF-16 4486** TEXT in bytes 4487** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4488** datatype of the result 4489** </table></blockquote> 4490** 4491** <b>Details:</b> 4492** 4493** ^These routines return information about a single column of the current 4494** result row of a query. ^In every case the first argument is a pointer 4495** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4496** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4497** and the second argument is the index of the column for which information 4498** should be returned. ^The leftmost column of the result set has the index 0. 4499** ^The number of columns in the result can be determined using 4500** [sqlite3_column_count()]. 4501** 4502** If the SQL statement does not currently point to a valid row, or if the 4503** column index is out of range, the result is undefined. 4504** These routines may only be called when the most recent call to 4505** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4506** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4507** If any of these routines are called after [sqlite3_reset()] or 4508** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4509** something other than [SQLITE_ROW], the results are undefined. 4510** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4511** are called from a different thread while any of these routines 4512** are pending, then the results are undefined. 4513** 4514** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4515** each return the value of a result column in a specific data format. If 4516** the result column is not initially in the requested format (for example, 4517** if the query returns an integer but the sqlite3_column_text() interface 4518** is used to extract the value) then an automatic type conversion is performed. 4519** 4520** ^The sqlite3_column_type() routine returns the 4521** [SQLITE_INTEGER | datatype code] for the initial data type 4522** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4523** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4524** The return value of sqlite3_column_type() can be used to decide which 4525** of the first six interface should be used to extract the column value. 4526** The value returned by sqlite3_column_type() is only meaningful if no 4527** automatic type conversions have occurred for the value in question. 4528** After a type conversion, the result of calling sqlite3_column_type() 4529** is undefined, though harmless. Future 4530** versions of SQLite may change the behavior of sqlite3_column_type() 4531** following a type conversion. 4532** 4533** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4534** or sqlite3_column_bytes16() interfaces can be used to determine the size 4535** of that BLOB or string. 4536** 4537** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4538** routine returns the number of bytes in that BLOB or string. 4539** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4540** the string to UTF-8 and then returns the number of bytes. 4541** ^If the result is a numeric value then sqlite3_column_bytes() uses 4542** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4543** the number of bytes in that string. 4544** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4545** 4546** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4547** routine returns the number of bytes in that BLOB or string. 4548** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4549** the string to UTF-16 and then returns the number of bytes. 4550** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4551** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4552** the number of bytes in that string. 4553** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4554** 4555** ^The values returned by [sqlite3_column_bytes()] and 4556** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4557** of the string. ^For clarity: the values returned by 4558** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4559** bytes in the string, not the number of characters. 4560** 4561** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4562** even empty strings, are always zero-terminated. ^The return 4563** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4564** 4565** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4566** [unprotected sqlite3_value] object. In a multithreaded environment, 4567** an unprotected sqlite3_value object may only be used safely with 4568** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4569** If the [unprotected sqlite3_value] object returned by 4570** [sqlite3_column_value()] is used in any other way, including calls 4571** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4572** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4573** Hence, the sqlite3_column_value() interface 4574** is normally only useful within the implementation of 4575** [application-defined SQL functions] or [virtual tables], not within 4576** top-level application code. 4577** 4578** The these routines may attempt to convert the datatype of the result. 4579** ^For example, if the internal representation is FLOAT and a text result 4580** is requested, [sqlite3_snprintf()] is used internally to perform the 4581** conversion automatically. ^(The following table details the conversions 4582** that are applied: 4583** 4584** <blockquote> 4585** <table border="1"> 4586** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4587** 4588** <tr><td> NULL <td> INTEGER <td> Result is 0 4589** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4590** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4591** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4592** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4593** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4594** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4595** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4596** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4597** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4598** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4599** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4600** <tr><td> TEXT <td> BLOB <td> No change 4601** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4602** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4603** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4604** </table> 4605** </blockquote>)^ 4606** 4607** Note that when type conversions occur, pointers returned by prior 4608** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4609** sqlite3_column_text16() may be invalidated. 4610** Type conversions and pointer invalidations might occur 4611** in the following cases: 4612** 4613** <ul> 4614** <li> The initial content is a BLOB and sqlite3_column_text() or 4615** sqlite3_column_text16() is called. A zero-terminator might 4616** need to be added to the string.</li> 4617** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4618** sqlite3_column_text16() is called. The content must be converted 4619** to UTF-16.</li> 4620** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4621** sqlite3_column_text() is called. The content must be converted 4622** to UTF-8.</li> 4623** </ul> 4624** 4625** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4626** not invalidate a prior pointer, though of course the content of the buffer 4627** that the prior pointer references will have been modified. Other kinds 4628** of conversion are done in place when it is possible, but sometimes they 4629** are not possible and in those cases prior pointers are invalidated. 4630** 4631** The safest policy is to invoke these routines 4632** in one of the following ways: 4633** 4634** <ul> 4635** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4636** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4637** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4638** </ul> 4639** 4640** In other words, you should call sqlite3_column_text(), 4641** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4642** into the desired format, then invoke sqlite3_column_bytes() or 4643** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4644** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4645** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4646** with calls to sqlite3_column_bytes(). 4647** 4648** ^The pointers returned are valid until a type conversion occurs as 4649** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4650** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4651** and BLOBs is freed automatically. Do not pass the pointers returned 4652** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4653** [sqlite3_free()]. 4654** 4655** As long as the input parameters are correct, these routines will only 4656** fail if an out-of-memory error occurs during a format conversion. 4657** Only the following subset of interfaces are subject to out-of-memory 4658** errors: 4659** 4660** <ul> 4661** <li> sqlite3_column_blob() 4662** <li> sqlite3_column_text() 4663** <li> sqlite3_column_text16() 4664** <li> sqlite3_column_bytes() 4665** <li> sqlite3_column_bytes16() 4666** </ul> 4667** 4668** If an out-of-memory error occurs, then the return value from these 4669** routines is the same as if the column had contained an SQL NULL value. 4670** Valid SQL NULL returns can be distinguished from out-of-memory errors 4671** by invoking the [sqlite3_errcode()] immediately after the suspect 4672** return value is obtained and before any 4673** other SQLite interface is called on the same [database connection]. 4674*/ 4675const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4676double sqlite3_column_double(sqlite3_stmt*, int iCol); 4677int sqlite3_column_int(sqlite3_stmt*, int iCol); 4678sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4679const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4680const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4681sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4682int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4683int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4684int sqlite3_column_type(sqlite3_stmt*, int iCol); 4685 4686/* 4687** CAPI3REF: Destroy A Prepared Statement Object 4688** DESTRUCTOR: sqlite3_stmt 4689** 4690** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4691** ^If the most recent evaluation of the statement encountered no errors 4692** or if the statement is never been evaluated, then sqlite3_finalize() returns 4693** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4694** sqlite3_finalize(S) returns the appropriate [error code] or 4695** [extended error code]. 4696** 4697** ^The sqlite3_finalize(S) routine can be called at any point during 4698** the life cycle of [prepared statement] S: 4699** before statement S is ever evaluated, after 4700** one or more calls to [sqlite3_reset()], or after any call 4701** to [sqlite3_step()] regardless of whether or not the statement has 4702** completed execution. 4703** 4704** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4705** 4706** The application must finalize every [prepared statement] in order to avoid 4707** resource leaks. It is a grievous error for the application to try to use 4708** a prepared statement after it has been finalized. Any use of a prepared 4709** statement after it has been finalized can result in undefined and 4710** undesirable behavior such as segfaults and heap corruption. 4711*/ 4712int sqlite3_finalize(sqlite3_stmt *pStmt); 4713 4714/* 4715** CAPI3REF: Reset A Prepared Statement Object 4716** METHOD: sqlite3_stmt 4717** 4718** The sqlite3_reset() function is called to reset a [prepared statement] 4719** object back to its initial state, ready to be re-executed. 4720** ^Any SQL statement variables that had values bound to them using 4721** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4722** Use [sqlite3_clear_bindings()] to reset the bindings. 4723** 4724** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4725** back to the beginning of its program. 4726** 4727** ^If the most recent call to [sqlite3_step(S)] for the 4728** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4729** or if [sqlite3_step(S)] has never before been called on S, 4730** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4731** 4732** ^If the most recent call to [sqlite3_step(S)] for the 4733** [prepared statement] S indicated an error, then 4734** [sqlite3_reset(S)] returns an appropriate [error code]. 4735** 4736** ^The [sqlite3_reset(S)] interface does not change the values 4737** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4738*/ 4739int sqlite3_reset(sqlite3_stmt *pStmt); 4740 4741/* 4742** CAPI3REF: Create Or Redefine SQL Functions 4743** KEYWORDS: {function creation routines} 4744** KEYWORDS: {application-defined SQL function} 4745** KEYWORDS: {application-defined SQL functions} 4746** METHOD: sqlite3 4747** 4748** ^These functions (collectively known as "function creation routines") 4749** are used to add SQL functions or aggregates or to redefine the behavior 4750** of existing SQL functions or aggregates. The only differences between 4751** the three "sqlite3_create_function*" routines are the text encoding 4752** expected for the second parameter (the name of the function being 4753** created) and the presence or absence of a destructor callback for 4754** the application data pointer. Function sqlite3_create_window_function() 4755** is similar, but allows the user to supply the extra callback functions 4756** needed by [aggregate window functions]. 4757** 4758** ^The first parameter is the [database connection] to which the SQL 4759** function is to be added. ^If an application uses more than one database 4760** connection then application-defined SQL functions must be added 4761** to each database connection separately. 4762** 4763** ^The second parameter is the name of the SQL function to be created or 4764** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4765** representation, exclusive of the zero-terminator. ^Note that the name 4766** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4767** ^Any attempt to create a function with a longer name 4768** will result in [SQLITE_MISUSE] being returned. 4769** 4770** ^The third parameter (nArg) 4771** is the number of arguments that the SQL function or 4772** aggregate takes. ^If this parameter is -1, then the SQL function or 4773** aggregate may take any number of arguments between 0 and the limit 4774** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4775** parameter is less than -1 or greater than 127 then the behavior is 4776** undefined. 4777** 4778** ^The fourth parameter, eTextRep, specifies what 4779** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4780** its parameters. The application should set this parameter to 4781** [SQLITE_UTF16LE] if the function implementation invokes 4782** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4783** implementation invokes [sqlite3_value_text16be()] on an input, or 4784** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4785** otherwise. ^The same SQL function may be registered multiple times using 4786** different preferred text encodings, with different implementations for 4787** each encoding. 4788** ^When multiple implementations of the same function are available, SQLite 4789** will pick the one that involves the least amount of data conversion. 4790** 4791** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4792** to signal that the function will always return the same result given 4793** the same inputs within a single SQL statement. Most SQL functions are 4794** deterministic. The built-in [random()] SQL function is an example of a 4795** function that is not deterministic. The SQLite query planner is able to 4796** perform additional optimizations on deterministic functions, so use 4797** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4798** 4799** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4800** function can gain access to this pointer using [sqlite3_user_data()].)^ 4801** 4802** ^The sixth, seventh and eighth parameters passed to the three 4803** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 4804** pointers to C-language functions that implement the SQL function or 4805** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4806** callback only; NULL pointers must be passed as the xStep and xFinal 4807** parameters. ^An aggregate SQL function requires an implementation of xStep 4808** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4809** SQL function or aggregate, pass NULL pointers for all three function 4810** callbacks. 4811** 4812** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 4813** and xInverse) passed to sqlite3_create_window_function are pointers to 4814** C-language callbacks that implement the new function. xStep and xFinal 4815** must both be non-NULL. xValue and xInverse may either both be NULL, in 4816** which case a regular aggregate function is created, or must both be 4817** non-NULL, in which case the new function may be used as either an aggregate 4818** or aggregate window function. More details regarding the implementation 4819** of aggregate window functions are 4820** [user-defined window functions|available here]. 4821** 4822** ^(If the final parameter to sqlite3_create_function_v2() or 4823** sqlite3_create_window_function() is not NULL, then it is destructor for 4824** the application data pointer. The destructor is invoked when the function 4825** is deleted, either by being overloaded or when the database connection 4826** closes.)^ ^The destructor is also invoked if the call to 4827** sqlite3_create_function_v2() fails. ^When the destructor callback is 4828** invoked, it is passed a single argument which is a copy of the application 4829** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 4830** 4831** ^It is permitted to register multiple implementations of the same 4832** functions with the same name but with either differing numbers of 4833** arguments or differing preferred text encodings. ^SQLite will use 4834** the implementation that most closely matches the way in which the 4835** SQL function is used. ^A function implementation with a non-negative 4836** nArg parameter is a better match than a function implementation with 4837** a negative nArg. ^A function where the preferred text encoding 4838** matches the database encoding is a better 4839** match than a function where the encoding is different. 4840** ^A function where the encoding difference is between UTF16le and UTF16be 4841** is a closer match than a function where the encoding difference is 4842** between UTF8 and UTF16. 4843** 4844** ^Built-in functions may be overloaded by new application-defined functions. 4845** 4846** ^An application-defined function is permitted to call other 4847** SQLite interfaces. However, such calls must not 4848** close the database connection nor finalize or reset the prepared 4849** statement in which the function is running. 4850*/ 4851int sqlite3_create_function( 4852 sqlite3 *db, 4853 const char *zFunctionName, 4854 int nArg, 4855 int eTextRep, 4856 void *pApp, 4857 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4858 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4859 void (*xFinal)(sqlite3_context*) 4860); 4861int sqlite3_create_function16( 4862 sqlite3 *db, 4863 const void *zFunctionName, 4864 int nArg, 4865 int eTextRep, 4866 void *pApp, 4867 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4868 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4869 void (*xFinal)(sqlite3_context*) 4870); 4871int sqlite3_create_function_v2( 4872 sqlite3 *db, 4873 const char *zFunctionName, 4874 int nArg, 4875 int eTextRep, 4876 void *pApp, 4877 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4878 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4879 void (*xFinal)(sqlite3_context*), 4880 void(*xDestroy)(void*) 4881); 4882int sqlite3_create_window_function( 4883 sqlite3 *db, 4884 const char *zFunctionName, 4885 int nArg, 4886 int eTextRep, 4887 void *pApp, 4888 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4889 void (*xFinal)(sqlite3_context*), 4890 void (*xValue)(sqlite3_context*), 4891 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 4892 void(*xDestroy)(void*) 4893); 4894 4895/* 4896** CAPI3REF: Text Encodings 4897** 4898** These constant define integer codes that represent the various 4899** text encodings supported by SQLite. 4900*/ 4901#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4902#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4903#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4904#define SQLITE_UTF16 4 /* Use native byte order */ 4905#define SQLITE_ANY 5 /* Deprecated */ 4906#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4907 4908/* 4909** CAPI3REF: Function Flags 4910** 4911** These constants may be ORed together with the 4912** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4913** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4914** [sqlite3_create_function_v2()]. 4915*/ 4916#define SQLITE_DETERMINISTIC 0x800 4917 4918/* 4919** CAPI3REF: Deprecated Functions 4920** DEPRECATED 4921** 4922** These functions are [deprecated]. In order to maintain 4923** backwards compatibility with older code, these functions continue 4924** to be supported. However, new applications should avoid 4925** the use of these functions. To encourage programmers to avoid 4926** these functions, we will not explain what they do. 4927*/ 4928#ifndef SQLITE_OMIT_DEPRECATED 4929SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4930SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4931SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4932SQLITE_DEPRECATED int sqlite3_global_recover(void); 4933SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4934SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4935 void*,sqlite3_int64); 4936#endif 4937 4938/* 4939** CAPI3REF: Obtaining SQL Values 4940** METHOD: sqlite3_value 4941** 4942** <b>Summary:</b> 4943** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4944** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4945** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4946** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 4947** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 4948** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 4949** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 4950** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 4951** the native byteorder 4952** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 4953** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 4954** <tr><td> <td> <td> 4955** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 4956** or a UTF-8 TEXT in bytes 4957** <tr><td><b>sqlite3_value_bytes16 </b> 4958** <td>→ <td>Size of UTF-16 4959** TEXT in bytes 4960** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 4961** datatype of the value 4962** <tr><td><b>sqlite3_value_numeric_type </b> 4963** <td>→ <td>Best numeric datatype of the value 4964** <tr><td><b>sqlite3_value_nochange </b> 4965** <td>→ <td>True if the column is unchanged in an UPDATE 4966** against a virtual table. 4967** </table></blockquote> 4968** 4969** <b>Details:</b> 4970** 4971** These routines extract type, size, and content information from 4972** [protected sqlite3_value] objects. Protected sqlite3_value objects 4973** are used to pass parameter information into implementation of 4974** [application-defined SQL functions] and [virtual tables]. 4975** 4976** These routines work only with [protected sqlite3_value] objects. 4977** Any attempt to use these routines on an [unprotected sqlite3_value] 4978** is not threadsafe. 4979** 4980** ^These routines work just like the corresponding [column access functions] 4981** except that these routines take a single [protected sqlite3_value] object 4982** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 4983** 4984** ^The sqlite3_value_text16() interface extracts a UTF-16 string 4985** in the native byte-order of the host machine. ^The 4986** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 4987** extract UTF-16 strings as big-endian and little-endian respectively. 4988** 4989** ^If [sqlite3_value] object V was initialized 4990** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 4991** and if X and Y are strings that compare equal according to strcmp(X,Y), 4992** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 4993** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 4994** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 4995** 4996** ^(The sqlite3_value_type(V) interface returns the 4997** [SQLITE_INTEGER | datatype code] for the initial datatype of the 4998** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 4999** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5000** Other interfaces might change the datatype for an sqlite3_value object. 5001** For example, if the datatype is initially SQLITE_INTEGER and 5002** sqlite3_value_text(V) is called to extract a text value for that 5003** integer, then subsequent calls to sqlite3_value_type(V) might return 5004** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5005** occurs is undefined and may change from one release of SQLite to the next. 5006** 5007** ^(The sqlite3_value_numeric_type() interface attempts to apply 5008** numeric affinity to the value. This means that an attempt is 5009** made to convert the value to an integer or floating point. If 5010** such a conversion is possible without loss of information (in other 5011** words, if the value is a string that looks like a number) 5012** then the conversion is performed. Otherwise no conversion occurs. 5013** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5014** 5015** ^Within the [xUpdate] method of a [virtual table], the 5016** sqlite3_value_nochange(X) interface returns true if and only if 5017** the column corresponding to X is unchanged by the UPDATE operation 5018** that the xUpdate method call was invoked to implement and if 5019** and the prior [xColumn] method call that was invoked to extracted 5020** the value for that column returned without setting a result (probably 5021** because it queried [sqlite3_vtab_nochange()] and found that the column 5022** was unchanging). ^Within an [xUpdate] method, any value for which 5023** sqlite3_value_nochange(X) is true will in all other respects appear 5024** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5025** than within an [xUpdate] method call for an UPDATE statement, then 5026** the return value is arbitrary and meaningless. 5027** 5028** Please pay particular attention to the fact that the pointer returned 5029** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5030** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5031** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5032** or [sqlite3_value_text16()]. 5033** 5034** These routines must be called from the same thread as 5035** the SQL function that supplied the [sqlite3_value*] parameters. 5036** 5037** As long as the input parameter is correct, these routines can only 5038** fail if an out-of-memory error occurs during a format conversion. 5039** Only the following subset of interfaces are subject to out-of-memory 5040** errors: 5041** 5042** <ul> 5043** <li> sqlite3_value_blob() 5044** <li> sqlite3_value_text() 5045** <li> sqlite3_value_text16() 5046** <li> sqlite3_value_text16le() 5047** <li> sqlite3_value_text16be() 5048** <li> sqlite3_value_bytes() 5049** <li> sqlite3_value_bytes16() 5050** </ul> 5051** 5052** If an out-of-memory error occurs, then the return value from these 5053** routines is the same as if the column had contained an SQL NULL value. 5054** Valid SQL NULL returns can be distinguished from out-of-memory errors 5055** by invoking the [sqlite3_errcode()] immediately after the suspect 5056** return value is obtained and before any 5057** other SQLite interface is called on the same [database connection]. 5058*/ 5059const void *sqlite3_value_blob(sqlite3_value*); 5060double sqlite3_value_double(sqlite3_value*); 5061int sqlite3_value_int(sqlite3_value*); 5062sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5063void *sqlite3_value_pointer(sqlite3_value*, const char*); 5064const unsigned char *sqlite3_value_text(sqlite3_value*); 5065const void *sqlite3_value_text16(sqlite3_value*); 5066const void *sqlite3_value_text16le(sqlite3_value*); 5067const void *sqlite3_value_text16be(sqlite3_value*); 5068int sqlite3_value_bytes(sqlite3_value*); 5069int sqlite3_value_bytes16(sqlite3_value*); 5070int sqlite3_value_type(sqlite3_value*); 5071int sqlite3_value_numeric_type(sqlite3_value*); 5072int sqlite3_value_nochange(sqlite3_value*); 5073 5074/* 5075** CAPI3REF: Finding The Subtype Of SQL Values 5076** METHOD: sqlite3_value 5077** 5078** The sqlite3_value_subtype(V) function returns the subtype for 5079** an [application-defined SQL function] argument V. The subtype 5080** information can be used to pass a limited amount of context from 5081** one SQL function to another. Use the [sqlite3_result_subtype()] 5082** routine to set the subtype for the return value of an SQL function. 5083*/ 5084unsigned int sqlite3_value_subtype(sqlite3_value*); 5085 5086/* 5087** CAPI3REF: Copy And Free SQL Values 5088** METHOD: sqlite3_value 5089** 5090** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5091** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5092** is a [protected sqlite3_value] object even if the input is not. 5093** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5094** memory allocation fails. 5095** 5096** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5097** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5098** then sqlite3_value_free(V) is a harmless no-op. 5099*/ 5100sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5101void sqlite3_value_free(sqlite3_value*); 5102 5103/* 5104** CAPI3REF: Obtain Aggregate Function Context 5105** METHOD: sqlite3_context 5106** 5107** Implementations of aggregate SQL functions use this 5108** routine to allocate memory for storing their state. 5109** 5110** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5111** for a particular aggregate function, SQLite 5112** allocates N of memory, zeroes out that memory, and returns a pointer 5113** to the new memory. ^On second and subsequent calls to 5114** sqlite3_aggregate_context() for the same aggregate function instance, 5115** the same buffer is returned. Sqlite3_aggregate_context() is normally 5116** called once for each invocation of the xStep callback and then one 5117** last time when the xFinal callback is invoked. ^(When no rows match 5118** an aggregate query, the xStep() callback of the aggregate function 5119** implementation is never called and xFinal() is called exactly once. 5120** In those cases, sqlite3_aggregate_context() might be called for the 5121** first time from within xFinal().)^ 5122** 5123** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5124** when first called if N is less than or equal to zero or if a memory 5125** allocate error occurs. 5126** 5127** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5128** determined by the N parameter on first successful call. Changing the 5129** value of N in subsequent call to sqlite3_aggregate_context() within 5130** the same aggregate function instance will not resize the memory 5131** allocation.)^ Within the xFinal callback, it is customary to set 5132** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5133** pointless memory allocations occur. 5134** 5135** ^SQLite automatically frees the memory allocated by 5136** sqlite3_aggregate_context() when the aggregate query concludes. 5137** 5138** The first parameter must be a copy of the 5139** [sqlite3_context | SQL function context] that is the first parameter 5140** to the xStep or xFinal callback routine that implements the aggregate 5141** function. 5142** 5143** This routine must be called from the same thread in which 5144** the aggregate SQL function is running. 5145*/ 5146void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5147 5148/* 5149** CAPI3REF: User Data For Functions 5150** METHOD: sqlite3_context 5151** 5152** ^The sqlite3_user_data() interface returns a copy of 5153** the pointer that was the pUserData parameter (the 5th parameter) 5154** of the [sqlite3_create_function()] 5155** and [sqlite3_create_function16()] routines that originally 5156** registered the application defined function. 5157** 5158** This routine must be called from the same thread in which 5159** the application-defined function is running. 5160*/ 5161void *sqlite3_user_data(sqlite3_context*); 5162 5163/* 5164** CAPI3REF: Database Connection For Functions 5165** METHOD: sqlite3_context 5166** 5167** ^The sqlite3_context_db_handle() interface returns a copy of 5168** the pointer to the [database connection] (the 1st parameter) 5169** of the [sqlite3_create_function()] 5170** and [sqlite3_create_function16()] routines that originally 5171** registered the application defined function. 5172*/ 5173sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5174 5175/* 5176** CAPI3REF: Function Auxiliary Data 5177** METHOD: sqlite3_context 5178** 5179** These functions may be used by (non-aggregate) SQL functions to 5180** associate metadata with argument values. If the same value is passed to 5181** multiple invocations of the same SQL function during query execution, under 5182** some circumstances the associated metadata may be preserved. An example 5183** of where this might be useful is in a regular-expression matching 5184** function. The compiled version of the regular expression can be stored as 5185** metadata associated with the pattern string. 5186** Then as long as the pattern string remains the same, 5187** the compiled regular expression can be reused on multiple 5188** invocations of the same function. 5189** 5190** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5191** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5192** value to the application-defined function. ^N is zero for the left-most 5193** function argument. ^If there is no metadata 5194** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5195** returns a NULL pointer. 5196** 5197** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5198** argument of the application-defined function. ^Subsequent 5199** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5200** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5201** NULL if the metadata has been discarded. 5202** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5203** SQLite will invoke the destructor function X with parameter P exactly 5204** once, when the metadata is discarded. 5205** SQLite is free to discard the metadata at any time, including: <ul> 5206** <li> ^(when the corresponding function parameter changes)^, or 5207** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5208** SQL statement)^, or 5209** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5210** parameter)^, or 5211** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5212** allocation error occurs.)^ </ul> 5213** 5214** Note the last bullet in particular. The destructor X in 5215** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5216** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5217** should be called near the end of the function implementation and the 5218** function implementation should not make any use of P after 5219** sqlite3_set_auxdata() has been called. 5220** 5221** ^(In practice, metadata is preserved between function calls for 5222** function parameters that are compile-time constants, including literal 5223** values and [parameters] and expressions composed from the same.)^ 5224** 5225** The value of the N parameter to these interfaces should be non-negative. 5226** Future enhancements may make use of negative N values to define new 5227** kinds of function caching behavior. 5228** 5229** These routines must be called from the same thread in which 5230** the SQL function is running. 5231*/ 5232void *sqlite3_get_auxdata(sqlite3_context*, int N); 5233void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5234 5235 5236/* 5237** CAPI3REF: Constants Defining Special Destructor Behavior 5238** 5239** These are special values for the destructor that is passed in as the 5240** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5241** argument is SQLITE_STATIC, it means that the content pointer is constant 5242** and will never change. It does not need to be destroyed. ^The 5243** SQLITE_TRANSIENT value means that the content will likely change in 5244** the near future and that SQLite should make its own private copy of 5245** the content before returning. 5246** 5247** The typedef is necessary to work around problems in certain 5248** C++ compilers. 5249*/ 5250typedef void (*sqlite3_destructor_type)(void*); 5251#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5252#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5253 5254/* 5255** CAPI3REF: Setting The Result Of An SQL Function 5256** METHOD: sqlite3_context 5257** 5258** These routines are used by the xFunc or xFinal callbacks that 5259** implement SQL functions and aggregates. See 5260** [sqlite3_create_function()] and [sqlite3_create_function16()] 5261** for additional information. 5262** 5263** These functions work very much like the [parameter binding] family of 5264** functions used to bind values to host parameters in prepared statements. 5265** Refer to the [SQL parameter] documentation for additional information. 5266** 5267** ^The sqlite3_result_blob() interface sets the result from 5268** an application-defined function to be the BLOB whose content is pointed 5269** to by the second parameter and which is N bytes long where N is the 5270** third parameter. 5271** 5272** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5273** interfaces set the result of the application-defined function to be 5274** a BLOB containing all zero bytes and N bytes in size. 5275** 5276** ^The sqlite3_result_double() interface sets the result from 5277** an application-defined function to be a floating point value specified 5278** by its 2nd argument. 5279** 5280** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5281** cause the implemented SQL function to throw an exception. 5282** ^SQLite uses the string pointed to by the 5283** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5284** as the text of an error message. ^SQLite interprets the error 5285** message string from sqlite3_result_error() as UTF-8. ^SQLite 5286** interprets the string from sqlite3_result_error16() as UTF-16 in native 5287** byte order. ^If the third parameter to sqlite3_result_error() 5288** or sqlite3_result_error16() is negative then SQLite takes as the error 5289** message all text up through the first zero character. 5290** ^If the third parameter to sqlite3_result_error() or 5291** sqlite3_result_error16() is non-negative then SQLite takes that many 5292** bytes (not characters) from the 2nd parameter as the error message. 5293** ^The sqlite3_result_error() and sqlite3_result_error16() 5294** routines make a private copy of the error message text before 5295** they return. Hence, the calling function can deallocate or 5296** modify the text after they return without harm. 5297** ^The sqlite3_result_error_code() function changes the error code 5298** returned by SQLite as a result of an error in a function. ^By default, 5299** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5300** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5301** 5302** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5303** error indicating that a string or BLOB is too long to represent. 5304** 5305** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5306** error indicating that a memory allocation failed. 5307** 5308** ^The sqlite3_result_int() interface sets the return value 5309** of the application-defined function to be the 32-bit signed integer 5310** value given in the 2nd argument. 5311** ^The sqlite3_result_int64() interface sets the return value 5312** of the application-defined function to be the 64-bit signed integer 5313** value given in the 2nd argument. 5314** 5315** ^The sqlite3_result_null() interface sets the return value 5316** of the application-defined function to be NULL. 5317** 5318** ^The sqlite3_result_text(), sqlite3_result_text16(), 5319** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5320** set the return value of the application-defined function to be 5321** a text string which is represented as UTF-8, UTF-16 native byte order, 5322** UTF-16 little endian, or UTF-16 big endian, respectively. 5323** ^The sqlite3_result_text64() interface sets the return value of an 5324** application-defined function to be a text string in an encoding 5325** specified by the fifth (and last) parameter, which must be one 5326** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5327** ^SQLite takes the text result from the application from 5328** the 2nd parameter of the sqlite3_result_text* interfaces. 5329** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5330** is negative, then SQLite takes result text from the 2nd parameter 5331** through the first zero character. 5332** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5333** is non-negative, then as many bytes (not characters) of the text 5334** pointed to by the 2nd parameter are taken as the application-defined 5335** function result. If the 3rd parameter is non-negative, then it 5336** must be the byte offset into the string where the NUL terminator would 5337** appear if the string where NUL terminated. If any NUL characters occur 5338** in the string at a byte offset that is less than the value of the 3rd 5339** parameter, then the resulting string will contain embedded NULs and the 5340** result of expressions operating on strings with embedded NULs is undefined. 5341** ^If the 4th parameter to the sqlite3_result_text* interfaces 5342** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5343** function as the destructor on the text or BLOB result when it has 5344** finished using that result. 5345** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5346** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5347** assumes that the text or BLOB result is in constant space and does not 5348** copy the content of the parameter nor call a destructor on the content 5349** when it has finished using that result. 5350** ^If the 4th parameter to the sqlite3_result_text* interfaces 5351** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5352** then SQLite makes a copy of the result into space obtained 5353** from [sqlite3_malloc()] before it returns. 5354** 5355** ^The sqlite3_result_value() interface sets the result of 5356** the application-defined function to be a copy of the 5357** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5358** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5359** so that the [sqlite3_value] specified in the parameter may change or 5360** be deallocated after sqlite3_result_value() returns without harm. 5361** ^A [protected sqlite3_value] object may always be used where an 5362** [unprotected sqlite3_value] object is required, so either 5363** kind of [sqlite3_value] object can be used with this interface. 5364** 5365** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5366** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5367** also associates the host-language pointer P or type T with that 5368** NULL value such that the pointer can be retrieved within an 5369** [application-defined SQL function] using [sqlite3_value_pointer()]. 5370** ^If the D parameter is not NULL, then it is a pointer to a destructor 5371** for the P parameter. ^SQLite invokes D with P as its only argument 5372** when SQLite is finished with P. The T parameter should be a static 5373** string and preferably a string literal. The sqlite3_result_pointer() 5374** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5375** 5376** If these routines are called from within the different thread 5377** than the one containing the application-defined function that received 5378** the [sqlite3_context] pointer, the results are undefined. 5379*/ 5380void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5381void sqlite3_result_blob64(sqlite3_context*,const void*, 5382 sqlite3_uint64,void(*)(void*)); 5383void sqlite3_result_double(sqlite3_context*, double); 5384void sqlite3_result_error(sqlite3_context*, const char*, int); 5385void sqlite3_result_error16(sqlite3_context*, const void*, int); 5386void sqlite3_result_error_toobig(sqlite3_context*); 5387void sqlite3_result_error_nomem(sqlite3_context*); 5388void sqlite3_result_error_code(sqlite3_context*, int); 5389void sqlite3_result_int(sqlite3_context*, int); 5390void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5391void sqlite3_result_null(sqlite3_context*); 5392void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5393void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5394 void(*)(void*), unsigned char encoding); 5395void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5396void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5397void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5398void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5399void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5400void sqlite3_result_zeroblob(sqlite3_context*, int n); 5401int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5402 5403 5404/* 5405** CAPI3REF: Setting The Subtype Of An SQL Function 5406** METHOD: sqlite3_context 5407** 5408** The sqlite3_result_subtype(C,T) function causes the subtype of 5409** the result from the [application-defined SQL function] with 5410** [sqlite3_context] C to be the value T. Only the lower 8 bits 5411** of the subtype T are preserved in current versions of SQLite; 5412** higher order bits are discarded. 5413** The number of subtype bytes preserved by SQLite might increase 5414** in future releases of SQLite. 5415*/ 5416void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5417 5418/* 5419** CAPI3REF: Define New Collating Sequences 5420** METHOD: sqlite3 5421** 5422** ^These functions add, remove, or modify a [collation] associated 5423** with the [database connection] specified as the first argument. 5424** 5425** ^The name of the collation is a UTF-8 string 5426** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5427** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5428** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5429** considered to be the same name. 5430** 5431** ^(The third argument (eTextRep) must be one of the constants: 5432** <ul> 5433** <li> [SQLITE_UTF8], 5434** <li> [SQLITE_UTF16LE], 5435** <li> [SQLITE_UTF16BE], 5436** <li> [SQLITE_UTF16], or 5437** <li> [SQLITE_UTF16_ALIGNED]. 5438** </ul>)^ 5439** ^The eTextRep argument determines the encoding of strings passed 5440** to the collating function callback, xCallback. 5441** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5442** force strings to be UTF16 with native byte order. 5443** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5444** on an even byte address. 5445** 5446** ^The fourth argument, pArg, is an application data pointer that is passed 5447** through as the first argument to the collating function callback. 5448** 5449** ^The fifth argument, xCallback, is a pointer to the collating function. 5450** ^Multiple collating functions can be registered using the same name but 5451** with different eTextRep parameters and SQLite will use whichever 5452** function requires the least amount of data transformation. 5453** ^If the xCallback argument is NULL then the collating function is 5454** deleted. ^When all collating functions having the same name are deleted, 5455** that collation is no longer usable. 5456** 5457** ^The collating function callback is invoked with a copy of the pArg 5458** application data pointer and with two strings in the encoding specified 5459** by the eTextRep argument. The collating function must return an 5460** integer that is negative, zero, or positive 5461** if the first string is less than, equal to, or greater than the second, 5462** respectively. A collating function must always return the same answer 5463** given the same inputs. If two or more collating functions are registered 5464** to the same collation name (using different eTextRep values) then all 5465** must give an equivalent answer when invoked with equivalent strings. 5466** The collating function must obey the following properties for all 5467** strings A, B, and C: 5468** 5469** <ol> 5470** <li> If A==B then B==A. 5471** <li> If A==B and B==C then A==C. 5472** <li> If A<B THEN B>A. 5473** <li> If A<B and B<C then A<C. 5474** </ol> 5475** 5476** If a collating function fails any of the above constraints and that 5477** collating function is registered and used, then the behavior of SQLite 5478** is undefined. 5479** 5480** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5481** with the addition that the xDestroy callback is invoked on pArg when 5482** the collating function is deleted. 5483** ^Collating functions are deleted when they are overridden by later 5484** calls to the collation creation functions or when the 5485** [database connection] is closed using [sqlite3_close()]. 5486** 5487** ^The xDestroy callback is <u>not</u> called if the 5488** sqlite3_create_collation_v2() function fails. Applications that invoke 5489** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5490** check the return code and dispose of the application data pointer 5491** themselves rather than expecting SQLite to deal with it for them. 5492** This is different from every other SQLite interface. The inconsistency 5493** is unfortunate but cannot be changed without breaking backwards 5494** compatibility. 5495** 5496** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5497*/ 5498int sqlite3_create_collation( 5499 sqlite3*, 5500 const char *zName, 5501 int eTextRep, 5502 void *pArg, 5503 int(*xCompare)(void*,int,const void*,int,const void*) 5504); 5505int sqlite3_create_collation_v2( 5506 sqlite3*, 5507 const char *zName, 5508 int eTextRep, 5509 void *pArg, 5510 int(*xCompare)(void*,int,const void*,int,const void*), 5511 void(*xDestroy)(void*) 5512); 5513int sqlite3_create_collation16( 5514 sqlite3*, 5515 const void *zName, 5516 int eTextRep, 5517 void *pArg, 5518 int(*xCompare)(void*,int,const void*,int,const void*) 5519); 5520 5521/* 5522** CAPI3REF: Collation Needed Callbacks 5523** METHOD: sqlite3 5524** 5525** ^To avoid having to register all collation sequences before a database 5526** can be used, a single callback function may be registered with the 5527** [database connection] to be invoked whenever an undefined collation 5528** sequence is required. 5529** 5530** ^If the function is registered using the sqlite3_collation_needed() API, 5531** then it is passed the names of undefined collation sequences as strings 5532** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5533** the names are passed as UTF-16 in machine native byte order. 5534** ^A call to either function replaces the existing collation-needed callback. 5535** 5536** ^(When the callback is invoked, the first argument passed is a copy 5537** of the second argument to sqlite3_collation_needed() or 5538** sqlite3_collation_needed16(). The second argument is the database 5539** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5540** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5541** sequence function required. The fourth parameter is the name of the 5542** required collation sequence.)^ 5543** 5544** The callback function should register the desired collation using 5545** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5546** [sqlite3_create_collation_v2()]. 5547*/ 5548int sqlite3_collation_needed( 5549 sqlite3*, 5550 void*, 5551 void(*)(void*,sqlite3*,int eTextRep,const char*) 5552); 5553int sqlite3_collation_needed16( 5554 sqlite3*, 5555 void*, 5556 void(*)(void*,sqlite3*,int eTextRep,const void*) 5557); 5558 5559#ifdef SQLITE_HAS_CODEC 5560/* 5561** Specify the key for an encrypted database. This routine should be 5562** called right after sqlite3_open(). 5563** 5564** The code to implement this API is not available in the public release 5565** of SQLite. 5566*/ 5567int sqlite3_key( 5568 sqlite3 *db, /* Database to be rekeyed */ 5569 const void *pKey, int nKey /* The key */ 5570); 5571int sqlite3_key_v2( 5572 sqlite3 *db, /* Database to be rekeyed */ 5573 const char *zDbName, /* Name of the database */ 5574 const void *pKey, int nKey /* The key */ 5575); 5576 5577/* 5578** Change the key on an open database. If the current database is not 5579** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5580** database is decrypted. 5581** 5582** The code to implement this API is not available in the public release 5583** of SQLite. 5584*/ 5585int sqlite3_rekey( 5586 sqlite3 *db, /* Database to be rekeyed */ 5587 const void *pKey, int nKey /* The new key */ 5588); 5589int sqlite3_rekey_v2( 5590 sqlite3 *db, /* Database to be rekeyed */ 5591 const char *zDbName, /* Name of the database */ 5592 const void *pKey, int nKey /* The new key */ 5593); 5594 5595/* 5596** Specify the activation key for a SEE database. Unless 5597** activated, none of the SEE routines will work. 5598*/ 5599void sqlite3_activate_see( 5600 const char *zPassPhrase /* Activation phrase */ 5601); 5602#endif 5603 5604#ifdef SQLITE_ENABLE_CEROD 5605/* 5606** Specify the activation key for a CEROD database. Unless 5607** activated, none of the CEROD routines will work. 5608*/ 5609void sqlite3_activate_cerod( 5610 const char *zPassPhrase /* Activation phrase */ 5611); 5612#endif 5613 5614/* 5615** CAPI3REF: Suspend Execution For A Short Time 5616** 5617** The sqlite3_sleep() function causes the current thread to suspend execution 5618** for at least a number of milliseconds specified in its parameter. 5619** 5620** If the operating system does not support sleep requests with 5621** millisecond time resolution, then the time will be rounded up to 5622** the nearest second. The number of milliseconds of sleep actually 5623** requested from the operating system is returned. 5624** 5625** ^SQLite implements this interface by calling the xSleep() 5626** method of the default [sqlite3_vfs] object. If the xSleep() method 5627** of the default VFS is not implemented correctly, or not implemented at 5628** all, then the behavior of sqlite3_sleep() may deviate from the description 5629** in the previous paragraphs. 5630*/ 5631int sqlite3_sleep(int); 5632 5633/* 5634** CAPI3REF: Name Of The Folder Holding Temporary Files 5635** 5636** ^(If this global variable is made to point to a string which is 5637** the name of a folder (a.k.a. directory), then all temporary files 5638** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5639** will be placed in that directory.)^ ^If this variable 5640** is a NULL pointer, then SQLite performs a search for an appropriate 5641** temporary file directory. 5642** 5643** Applications are strongly discouraged from using this global variable. 5644** It is required to set a temporary folder on Windows Runtime (WinRT). 5645** But for all other platforms, it is highly recommended that applications 5646** neither read nor write this variable. This global variable is a relic 5647** that exists for backwards compatibility of legacy applications and should 5648** be avoided in new projects. 5649** 5650** It is not safe to read or modify this variable in more than one 5651** thread at a time. It is not safe to read or modify this variable 5652** if a [database connection] is being used at the same time in a separate 5653** thread. 5654** It is intended that this variable be set once 5655** as part of process initialization and before any SQLite interface 5656** routines have been called and that this variable remain unchanged 5657** thereafter. 5658** 5659** ^The [temp_store_directory pragma] may modify this variable and cause 5660** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5661** the [temp_store_directory pragma] always assumes that any string 5662** that this variable points to is held in memory obtained from 5663** [sqlite3_malloc] and the pragma may attempt to free that memory 5664** using [sqlite3_free]. 5665** Hence, if this variable is modified directly, either it should be 5666** made NULL or made to point to memory obtained from [sqlite3_malloc] 5667** or else the use of the [temp_store_directory pragma] should be avoided. 5668** Except when requested by the [temp_store_directory pragma], SQLite 5669** does not free the memory that sqlite3_temp_directory points to. If 5670** the application wants that memory to be freed, it must do 5671** so itself, taking care to only do so after all [database connection] 5672** objects have been destroyed. 5673** 5674** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5675** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5676** features that require the use of temporary files may fail. Here is an 5677** example of how to do this using C++ with the Windows Runtime: 5678** 5679** <blockquote><pre> 5680** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5681** TemporaryFolder->Path->Data(); 5682** char zPathBuf[MAX_PATH + 1]; 5683** memset(zPathBuf, 0, sizeof(zPathBuf)); 5684** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5685** NULL, NULL); 5686** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5687** </pre></blockquote> 5688*/ 5689SQLITE_EXTERN char *sqlite3_temp_directory; 5690 5691/* 5692** CAPI3REF: Name Of The Folder Holding Database Files 5693** 5694** ^(If this global variable is made to point to a string which is 5695** the name of a folder (a.k.a. directory), then all database files 5696** specified with a relative pathname and created or accessed by 5697** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5698** to be relative to that directory.)^ ^If this variable is a NULL 5699** pointer, then SQLite assumes that all database files specified 5700** with a relative pathname are relative to the current directory 5701** for the process. Only the windows VFS makes use of this global 5702** variable; it is ignored by the unix VFS. 5703** 5704** Changing the value of this variable while a database connection is 5705** open can result in a corrupt database. 5706** 5707** It is not safe to read or modify this variable in more than one 5708** thread at a time. It is not safe to read or modify this variable 5709** if a [database connection] is being used at the same time in a separate 5710** thread. 5711** It is intended that this variable be set once 5712** as part of process initialization and before any SQLite interface 5713** routines have been called and that this variable remain unchanged 5714** thereafter. 5715** 5716** ^The [data_store_directory pragma] may modify this variable and cause 5717** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5718** the [data_store_directory pragma] always assumes that any string 5719** that this variable points to is held in memory obtained from 5720** [sqlite3_malloc] and the pragma may attempt to free that memory 5721** using [sqlite3_free]. 5722** Hence, if this variable is modified directly, either it should be 5723** made NULL or made to point to memory obtained from [sqlite3_malloc] 5724** or else the use of the [data_store_directory pragma] should be avoided. 5725*/ 5726SQLITE_EXTERN char *sqlite3_data_directory; 5727 5728/* 5729** CAPI3REF: Win32 Specific Interface 5730** 5731** These interfaces are available only on Windows. The 5732** [sqlite3_win32_set_directory] interface is used to set the value associated 5733** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 5734** zValue, depending on the value of the type parameter. The zValue parameter 5735** should be NULL to cause the previous value to be freed via [sqlite3_free]; 5736** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 5737** prior to being used. The [sqlite3_win32_set_directory] interface returns 5738** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 5739** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 5740** [sqlite3_data_directory] variable is intended to act as a replacement for 5741** the current directory on the sub-platforms of Win32 where that concept is 5742** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 5743** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 5744** sqlite3_win32_set_directory interface except the string parameter must be 5745** UTF-8 or UTF-16, respectively. 5746*/ 5747int sqlite3_win32_set_directory( 5748 unsigned long type, /* Identifier for directory being set or reset */ 5749 void *zValue /* New value for directory being set or reset */ 5750); 5751int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 5752int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 5753 5754/* 5755** CAPI3REF: Win32 Directory Types 5756** 5757** These macros are only available on Windows. They define the allowed values 5758** for the type argument to the [sqlite3_win32_set_directory] interface. 5759*/ 5760#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 5761#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 5762 5763/* 5764** CAPI3REF: Test For Auto-Commit Mode 5765** KEYWORDS: {autocommit mode} 5766** METHOD: sqlite3 5767** 5768** ^The sqlite3_get_autocommit() interface returns non-zero or 5769** zero if the given database connection is or is not in autocommit mode, 5770** respectively. ^Autocommit mode is on by default. 5771** ^Autocommit mode is disabled by a [BEGIN] statement. 5772** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5773** 5774** If certain kinds of errors occur on a statement within a multi-statement 5775** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5776** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5777** transaction might be rolled back automatically. The only way to 5778** find out whether SQLite automatically rolled back the transaction after 5779** an error is to use this function. 5780** 5781** If another thread changes the autocommit status of the database 5782** connection while this routine is running, then the return value 5783** is undefined. 5784*/ 5785int sqlite3_get_autocommit(sqlite3*); 5786 5787/* 5788** CAPI3REF: Find The Database Handle Of A Prepared Statement 5789** METHOD: sqlite3_stmt 5790** 5791** ^The sqlite3_db_handle interface returns the [database connection] handle 5792** to which a [prepared statement] belongs. ^The [database connection] 5793** returned by sqlite3_db_handle is the same [database connection] 5794** that was the first argument 5795** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5796** create the statement in the first place. 5797*/ 5798sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5799 5800/* 5801** CAPI3REF: Return The Filename For A Database Connection 5802** METHOD: sqlite3 5803** 5804** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5805** associated with database N of connection D. ^The main database file 5806** has the name "main". If there is no attached database N on the database 5807** connection D, or if database N is a temporary or in-memory database, then 5808** this function will return either a NULL pointer or an empty string. 5809** 5810** ^The filename returned by this function is the output of the 5811** xFullPathname method of the [VFS]. ^In other words, the filename 5812** will be an absolute pathname, even if the filename used 5813** to open the database originally was a URI or relative pathname. 5814*/ 5815const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5816 5817/* 5818** CAPI3REF: Determine if a database is read-only 5819** METHOD: sqlite3 5820** 5821** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5822** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5823** the name of a database on connection D. 5824*/ 5825int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5826 5827/* 5828** CAPI3REF: Find the next prepared statement 5829** METHOD: sqlite3 5830** 5831** ^This interface returns a pointer to the next [prepared statement] after 5832** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5833** then this interface returns a pointer to the first prepared statement 5834** associated with the database connection pDb. ^If no prepared statement 5835** satisfies the conditions of this routine, it returns NULL. 5836** 5837** The [database connection] pointer D in a call to 5838** [sqlite3_next_stmt(D,S)] must refer to an open database 5839** connection and in particular must not be a NULL pointer. 5840*/ 5841sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5842 5843/* 5844** CAPI3REF: Commit And Rollback Notification Callbacks 5845** METHOD: sqlite3 5846** 5847** ^The sqlite3_commit_hook() interface registers a callback 5848** function to be invoked whenever a transaction is [COMMIT | committed]. 5849** ^Any callback set by a previous call to sqlite3_commit_hook() 5850** for the same database connection is overridden. 5851** ^The sqlite3_rollback_hook() interface registers a callback 5852** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5853** ^Any callback set by a previous call to sqlite3_rollback_hook() 5854** for the same database connection is overridden. 5855** ^The pArg argument is passed through to the callback. 5856** ^If the callback on a commit hook function returns non-zero, 5857** then the commit is converted into a rollback. 5858** 5859** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5860** return the P argument from the previous call of the same function 5861** on the same [database connection] D, or NULL for 5862** the first call for each function on D. 5863** 5864** The commit and rollback hook callbacks are not reentrant. 5865** The callback implementation must not do anything that will modify 5866** the database connection that invoked the callback. Any actions 5867** to modify the database connection must be deferred until after the 5868** completion of the [sqlite3_step()] call that triggered the commit 5869** or rollback hook in the first place. 5870** Note that running any other SQL statements, including SELECT statements, 5871** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5872** the database connections for the meaning of "modify" in this paragraph. 5873** 5874** ^Registering a NULL function disables the callback. 5875** 5876** ^When the commit hook callback routine returns zero, the [COMMIT] 5877** operation is allowed to continue normally. ^If the commit hook 5878** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5879** ^The rollback hook is invoked on a rollback that results from a commit 5880** hook returning non-zero, just as it would be with any other rollback. 5881** 5882** ^For the purposes of this API, a transaction is said to have been 5883** rolled back if an explicit "ROLLBACK" statement is executed, or 5884** an error or constraint causes an implicit rollback to occur. 5885** ^The rollback callback is not invoked if a transaction is 5886** automatically rolled back because the database connection is closed. 5887** 5888** See also the [sqlite3_update_hook()] interface. 5889*/ 5890void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5891void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5892 5893/* 5894** CAPI3REF: Data Change Notification Callbacks 5895** METHOD: sqlite3 5896** 5897** ^The sqlite3_update_hook() interface registers a callback function 5898** with the [database connection] identified by the first argument 5899** to be invoked whenever a row is updated, inserted or deleted in 5900** a [rowid table]. 5901** ^Any callback set by a previous call to this function 5902** for the same database connection is overridden. 5903** 5904** ^The second argument is a pointer to the function to invoke when a 5905** row is updated, inserted or deleted in a rowid table. 5906** ^The first argument to the callback is a copy of the third argument 5907** to sqlite3_update_hook(). 5908** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5909** or [SQLITE_UPDATE], depending on the operation that caused the callback 5910** to be invoked. 5911** ^The third and fourth arguments to the callback contain pointers to the 5912** database and table name containing the affected row. 5913** ^The final callback parameter is the [rowid] of the row. 5914** ^In the case of an update, this is the [rowid] after the update takes place. 5915** 5916** ^(The update hook is not invoked when internal system tables are 5917** modified (i.e. sqlite_master and sqlite_sequence).)^ 5918** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5919** 5920** ^In the current implementation, the update hook 5921** is not invoked when conflicting rows are deleted because of an 5922** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5923** invoked when rows are deleted using the [truncate optimization]. 5924** The exceptions defined in this paragraph might change in a future 5925** release of SQLite. 5926** 5927** The update hook implementation must not do anything that will modify 5928** the database connection that invoked the update hook. Any actions 5929** to modify the database connection must be deferred until after the 5930** completion of the [sqlite3_step()] call that triggered the update hook. 5931** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5932** database connections for the meaning of "modify" in this paragraph. 5933** 5934** ^The sqlite3_update_hook(D,C,P) function 5935** returns the P argument from the previous call 5936** on the same [database connection] D, or NULL for 5937** the first call on D. 5938** 5939** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 5940** and [sqlite3_preupdate_hook()] interfaces. 5941*/ 5942void *sqlite3_update_hook( 5943 sqlite3*, 5944 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 5945 void* 5946); 5947 5948/* 5949** CAPI3REF: Enable Or Disable Shared Pager Cache 5950** 5951** ^(This routine enables or disables the sharing of the database cache 5952** and schema data structures between [database connection | connections] 5953** to the same database. Sharing is enabled if the argument is true 5954** and disabled if the argument is false.)^ 5955** 5956** ^Cache sharing is enabled and disabled for an entire process. 5957** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 5958** In prior versions of SQLite, 5959** sharing was enabled or disabled for each thread separately. 5960** 5961** ^(The cache sharing mode set by this interface effects all subsequent 5962** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 5963** Existing database connections continue use the sharing mode 5964** that was in effect at the time they were opened.)^ 5965** 5966** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 5967** successfully. An [error code] is returned otherwise.)^ 5968** 5969** ^Shared cache is disabled by default. But this might change in 5970** future releases of SQLite. Applications that care about shared 5971** cache setting should set it explicitly. 5972** 5973** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 5974** and will always return SQLITE_MISUSE. On those systems, 5975** shared cache mode should be enabled per-database connection via 5976** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 5977** 5978** This interface is threadsafe on processors where writing a 5979** 32-bit integer is atomic. 5980** 5981** See Also: [SQLite Shared-Cache Mode] 5982*/ 5983int sqlite3_enable_shared_cache(int); 5984 5985/* 5986** CAPI3REF: Attempt To Free Heap Memory 5987** 5988** ^The sqlite3_release_memory() interface attempts to free N bytes 5989** of heap memory by deallocating non-essential memory allocations 5990** held by the database library. Memory used to cache database 5991** pages to improve performance is an example of non-essential memory. 5992** ^sqlite3_release_memory() returns the number of bytes actually freed, 5993** which might be more or less than the amount requested. 5994** ^The sqlite3_release_memory() routine is a no-op returning zero 5995** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 5996** 5997** See also: [sqlite3_db_release_memory()] 5998*/ 5999int sqlite3_release_memory(int); 6000 6001/* 6002** CAPI3REF: Free Memory Used By A Database Connection 6003** METHOD: sqlite3 6004** 6005** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6006** memory as possible from database connection D. Unlike the 6007** [sqlite3_release_memory()] interface, this interface is in effect even 6008** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6009** omitted. 6010** 6011** See also: [sqlite3_release_memory()] 6012*/ 6013int sqlite3_db_release_memory(sqlite3*); 6014 6015/* 6016** CAPI3REF: Impose A Limit On Heap Size 6017** 6018** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6019** soft limit on the amount of heap memory that may be allocated by SQLite. 6020** ^SQLite strives to keep heap memory utilization below the soft heap 6021** limit by reducing the number of pages held in the page cache 6022** as heap memory usages approaches the limit. 6023** ^The soft heap limit is "soft" because even though SQLite strives to stay 6024** below the limit, it will exceed the limit rather than generate 6025** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6026** is advisory only. 6027** 6028** ^The return value from sqlite3_soft_heap_limit64() is the size of 6029** the soft heap limit prior to the call, or negative in the case of an 6030** error. ^If the argument N is negative 6031** then no change is made to the soft heap limit. Hence, the current 6032** size of the soft heap limit can be determined by invoking 6033** sqlite3_soft_heap_limit64() with a negative argument. 6034** 6035** ^If the argument N is zero then the soft heap limit is disabled. 6036** 6037** ^(The soft heap limit is not enforced in the current implementation 6038** if one or more of following conditions are true: 6039** 6040** <ul> 6041** <li> The soft heap limit is set to zero. 6042** <li> Memory accounting is disabled using a combination of the 6043** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6044** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6045** <li> An alternative page cache implementation is specified using 6046** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6047** <li> The page cache allocates from its own memory pool supplied 6048** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6049** from the heap. 6050** </ul>)^ 6051** 6052** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 6053** the soft heap limit is enforced 6054** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 6055** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 6056** the soft heap limit is enforced on every memory allocation. Without 6057** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 6058** when memory is allocated by the page cache. Testing suggests that because 6059** the page cache is the predominate memory user in SQLite, most 6060** applications will achieve adequate soft heap limit enforcement without 6061** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6062** 6063** The circumstances under which SQLite will enforce the soft heap limit may 6064** changes in future releases of SQLite. 6065*/ 6066sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6067 6068/* 6069** CAPI3REF: Deprecated Soft Heap Limit Interface 6070** DEPRECATED 6071** 6072** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6073** interface. This routine is provided for historical compatibility 6074** only. All new applications should use the 6075** [sqlite3_soft_heap_limit64()] interface rather than this one. 6076*/ 6077SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6078 6079 6080/* 6081** CAPI3REF: Extract Metadata About A Column Of A Table 6082** METHOD: sqlite3 6083** 6084** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6085** information about column C of table T in database D 6086** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6087** interface returns SQLITE_OK and fills in the non-NULL pointers in 6088** the final five arguments with appropriate values if the specified 6089** column exists. ^The sqlite3_table_column_metadata() interface returns 6090** SQLITE_ERROR and if the specified column does not exist. 6091** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6092** NULL pointer, then this routine simply checks for the existence of the 6093** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6094** does not. If the table name parameter T in a call to 6095** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6096** undefined behavior. 6097** 6098** ^The column is identified by the second, third and fourth parameters to 6099** this function. ^(The second parameter is either the name of the database 6100** (i.e. "main", "temp", or an attached database) containing the specified 6101** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6102** for the table using the same algorithm used by the database engine to 6103** resolve unqualified table references. 6104** 6105** ^The third and fourth parameters to this function are the table and column 6106** name of the desired column, respectively. 6107** 6108** ^Metadata is returned by writing to the memory locations passed as the 5th 6109** and subsequent parameters to this function. ^Any of these arguments may be 6110** NULL, in which case the corresponding element of metadata is omitted. 6111** 6112** ^(<blockquote> 6113** <table border="1"> 6114** <tr><th> Parameter <th> Output<br>Type <th> Description 6115** 6116** <tr><td> 5th <td> const char* <td> Data type 6117** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6118** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6119** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6120** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6121** </table> 6122** </blockquote>)^ 6123** 6124** ^The memory pointed to by the character pointers returned for the 6125** declaration type and collation sequence is valid until the next 6126** call to any SQLite API function. 6127** 6128** ^If the specified table is actually a view, an [error code] is returned. 6129** 6130** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6131** is not a [WITHOUT ROWID] table and an 6132** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6133** parameters are set for the explicitly declared column. ^(If there is no 6134** [INTEGER PRIMARY KEY] column, then the outputs 6135** for the [rowid] are set as follows: 6136** 6137** <pre> 6138** data type: "INTEGER" 6139** collation sequence: "BINARY" 6140** not null: 0 6141** primary key: 1 6142** auto increment: 0 6143** </pre>)^ 6144** 6145** ^This function causes all database schemas to be read from disk and 6146** parsed, if that has not already been done, and returns an error if 6147** any errors are encountered while loading the schema. 6148*/ 6149int sqlite3_table_column_metadata( 6150 sqlite3 *db, /* Connection handle */ 6151 const char *zDbName, /* Database name or NULL */ 6152 const char *zTableName, /* Table name */ 6153 const char *zColumnName, /* Column name */ 6154 char const **pzDataType, /* OUTPUT: Declared data type */ 6155 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6156 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6157 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6158 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6159); 6160 6161/* 6162** CAPI3REF: Load An Extension 6163** METHOD: sqlite3 6164** 6165** ^This interface loads an SQLite extension library from the named file. 6166** 6167** ^The sqlite3_load_extension() interface attempts to load an 6168** [SQLite extension] library contained in the file zFile. If 6169** the file cannot be loaded directly, attempts are made to load 6170** with various operating-system specific extensions added. 6171** So for example, if "samplelib" cannot be loaded, then names like 6172** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6173** be tried also. 6174** 6175** ^The entry point is zProc. 6176** ^(zProc may be 0, in which case SQLite will try to come up with an 6177** entry point name on its own. It first tries "sqlite3_extension_init". 6178** If that does not work, it constructs a name "sqlite3_X_init" where the 6179** X is consists of the lower-case equivalent of all ASCII alphabetic 6180** characters in the filename from the last "/" to the first following 6181** "." and omitting any initial "lib".)^ 6182** ^The sqlite3_load_extension() interface returns 6183** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6184** ^If an error occurs and pzErrMsg is not 0, then the 6185** [sqlite3_load_extension()] interface shall attempt to 6186** fill *pzErrMsg with error message text stored in memory 6187** obtained from [sqlite3_malloc()]. The calling function 6188** should free this memory by calling [sqlite3_free()]. 6189** 6190** ^Extension loading must be enabled using 6191** [sqlite3_enable_load_extension()] or 6192** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6193** prior to calling this API, 6194** otherwise an error will be returned. 6195** 6196** <b>Security warning:</b> It is recommended that the 6197** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6198** interface. The use of the [sqlite3_enable_load_extension()] interface 6199** should be avoided. This will keep the SQL function [load_extension()] 6200** disabled and prevent SQL injections from giving attackers 6201** access to extension loading capabilities. 6202** 6203** See also the [load_extension() SQL function]. 6204*/ 6205int sqlite3_load_extension( 6206 sqlite3 *db, /* Load the extension into this database connection */ 6207 const char *zFile, /* Name of the shared library containing extension */ 6208 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6209 char **pzErrMsg /* Put error message here if not 0 */ 6210); 6211 6212/* 6213** CAPI3REF: Enable Or Disable Extension Loading 6214** METHOD: sqlite3 6215** 6216** ^So as not to open security holes in older applications that are 6217** unprepared to deal with [extension loading], and as a means of disabling 6218** [extension loading] while evaluating user-entered SQL, the following API 6219** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6220** 6221** ^Extension loading is off by default. 6222** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6223** to turn extension loading on and call it with onoff==0 to turn 6224** it back off again. 6225** 6226** ^This interface enables or disables both the C-API 6227** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6228** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6229** to enable or disable only the C-API.)^ 6230** 6231** <b>Security warning:</b> It is recommended that extension loading 6232** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6233** rather than this interface, so the [load_extension()] SQL function 6234** remains disabled. This will prevent SQL injections from giving attackers 6235** access to extension loading capabilities. 6236*/ 6237int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6238 6239/* 6240** CAPI3REF: Automatically Load Statically Linked Extensions 6241** 6242** ^This interface causes the xEntryPoint() function to be invoked for 6243** each new [database connection] that is created. The idea here is that 6244** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6245** that is to be automatically loaded into all new database connections. 6246** 6247** ^(Even though the function prototype shows that xEntryPoint() takes 6248** no arguments and returns void, SQLite invokes xEntryPoint() with three 6249** arguments and expects an integer result as if the signature of the 6250** entry point where as follows: 6251** 6252** <blockquote><pre> 6253** int xEntryPoint( 6254** sqlite3 *db, 6255** const char **pzErrMsg, 6256** const struct sqlite3_api_routines *pThunk 6257** ); 6258** </pre></blockquote>)^ 6259** 6260** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6261** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6262** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6263** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6264** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6265** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6266** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6267** 6268** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6269** on the list of automatic extensions is a harmless no-op. ^No entry point 6270** will be called more than once for each database connection that is opened. 6271** 6272** See also: [sqlite3_reset_auto_extension()] 6273** and [sqlite3_cancel_auto_extension()] 6274*/ 6275int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6276 6277/* 6278** CAPI3REF: Cancel Automatic Extension Loading 6279** 6280** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6281** initialization routine X that was registered using a prior call to 6282** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6283** routine returns 1 if initialization routine X was successfully 6284** unregistered and it returns 0 if X was not on the list of initialization 6285** routines. 6286*/ 6287int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6288 6289/* 6290** CAPI3REF: Reset Automatic Extension Loading 6291** 6292** ^This interface disables all automatic extensions previously 6293** registered using [sqlite3_auto_extension()]. 6294*/ 6295void sqlite3_reset_auto_extension(void); 6296 6297/* 6298** The interface to the virtual-table mechanism is currently considered 6299** to be experimental. The interface might change in incompatible ways. 6300** If this is a problem for you, do not use the interface at this time. 6301** 6302** When the virtual-table mechanism stabilizes, we will declare the 6303** interface fixed, support it indefinitely, and remove this comment. 6304*/ 6305 6306/* 6307** Structures used by the virtual table interface 6308*/ 6309typedef struct sqlite3_vtab sqlite3_vtab; 6310typedef struct sqlite3_index_info sqlite3_index_info; 6311typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6312typedef struct sqlite3_module sqlite3_module; 6313 6314/* 6315** CAPI3REF: Virtual Table Object 6316** KEYWORDS: sqlite3_module {virtual table module} 6317** 6318** This structure, sometimes called a "virtual table module", 6319** defines the implementation of a [virtual tables]. 6320** This structure consists mostly of methods for the module. 6321** 6322** ^A virtual table module is created by filling in a persistent 6323** instance of this structure and passing a pointer to that instance 6324** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6325** ^The registration remains valid until it is replaced by a different 6326** module or until the [database connection] closes. The content 6327** of this structure must not change while it is registered with 6328** any database connection. 6329*/ 6330struct sqlite3_module { 6331 int iVersion; 6332 int (*xCreate)(sqlite3*, void *pAux, 6333 int argc, const char *const*argv, 6334 sqlite3_vtab **ppVTab, char**); 6335 int (*xConnect)(sqlite3*, void *pAux, 6336 int argc, const char *const*argv, 6337 sqlite3_vtab **ppVTab, char**); 6338 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6339 int (*xDisconnect)(sqlite3_vtab *pVTab); 6340 int (*xDestroy)(sqlite3_vtab *pVTab); 6341 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6342 int (*xClose)(sqlite3_vtab_cursor*); 6343 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6344 int argc, sqlite3_value **argv); 6345 int (*xNext)(sqlite3_vtab_cursor*); 6346 int (*xEof)(sqlite3_vtab_cursor*); 6347 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6348 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6349 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6350 int (*xBegin)(sqlite3_vtab *pVTab); 6351 int (*xSync)(sqlite3_vtab *pVTab); 6352 int (*xCommit)(sqlite3_vtab *pVTab); 6353 int (*xRollback)(sqlite3_vtab *pVTab); 6354 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6355 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6356 void **ppArg); 6357 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6358 /* The methods above are in version 1 of the sqlite_module object. Those 6359 ** below are for version 2 and greater. */ 6360 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6361 int (*xRelease)(sqlite3_vtab *pVTab, int); 6362 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6363 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6364 ** Those below are for version 3 and greater. */ 6365 int (*xShadowName)(const char*); 6366}; 6367 6368/* 6369** CAPI3REF: Virtual Table Indexing Information 6370** KEYWORDS: sqlite3_index_info 6371** 6372** The sqlite3_index_info structure and its substructures is used as part 6373** of the [virtual table] interface to 6374** pass information into and receive the reply from the [xBestIndex] 6375** method of a [virtual table module]. The fields under **Inputs** are the 6376** inputs to xBestIndex and are read-only. xBestIndex inserts its 6377** results into the **Outputs** fields. 6378** 6379** ^(The aConstraint[] array records WHERE clause constraints of the form: 6380** 6381** <blockquote>column OP expr</blockquote> 6382** 6383** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6384** stored in aConstraint[].op using one of the 6385** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6386** ^(The index of the column is stored in 6387** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6388** expr on the right-hand side can be evaluated (and thus the constraint 6389** is usable) and false if it cannot.)^ 6390** 6391** ^The optimizer automatically inverts terms of the form "expr OP column" 6392** and makes other simplifications to the WHERE clause in an attempt to 6393** get as many WHERE clause terms into the form shown above as possible. 6394** ^The aConstraint[] array only reports WHERE clause terms that are 6395** relevant to the particular virtual table being queried. 6396** 6397** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6398** ^Each term of aOrderBy records a column of the ORDER BY clause. 6399** 6400** The colUsed field indicates which columns of the virtual table may be 6401** required by the current scan. Virtual table columns are numbered from 6402** zero in the order in which they appear within the CREATE TABLE statement 6403** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6404** the corresponding bit is set within the colUsed mask if the column may be 6405** required by SQLite. If the table has at least 64 columns and any column 6406** to the right of the first 63 is required, then bit 63 of colUsed is also 6407** set. In other words, column iCol may be required if the expression 6408** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6409** non-zero. 6410** 6411** The [xBestIndex] method must fill aConstraintUsage[] with information 6412** about what parameters to pass to xFilter. ^If argvIndex>0 then 6413** the right-hand side of the corresponding aConstraint[] is evaluated 6414** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6415** is true, then the constraint is assumed to be fully handled by the 6416** virtual table and is not checked again by SQLite.)^ 6417** 6418** ^The idxNum and idxPtr values are recorded and passed into the 6419** [xFilter] method. 6420** ^[sqlite3_free()] is used to free idxPtr if and only if 6421** needToFreeIdxPtr is true. 6422** 6423** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6424** the correct order to satisfy the ORDER BY clause so that no separate 6425** sorting step is required. 6426** 6427** ^The estimatedCost value is an estimate of the cost of a particular 6428** strategy. A cost of N indicates that the cost of the strategy is similar 6429** to a linear scan of an SQLite table with N rows. A cost of log(N) 6430** indicates that the expense of the operation is similar to that of a 6431** binary search on a unique indexed field of an SQLite table with N rows. 6432** 6433** ^The estimatedRows value is an estimate of the number of rows that 6434** will be returned by the strategy. 6435** 6436** The xBestIndex method may optionally populate the idxFlags field with a 6437** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6438** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6439** assumes that the strategy may visit at most one row. 6440** 6441** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6442** SQLite also assumes that if a call to the xUpdate() method is made as 6443** part of the same statement to delete or update a virtual table row and the 6444** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6445** any database changes. In other words, if the xUpdate() returns 6446** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6447** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6448** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6449** the xUpdate method are automatically rolled back by SQLite. 6450** 6451** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6452** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6453** If a virtual table extension is 6454** used with an SQLite version earlier than 3.8.2, the results of attempting 6455** to read or write the estimatedRows field are undefined (but are likely 6456** to included crashing the application). The estimatedRows field should 6457** therefore only be used if [sqlite3_libversion_number()] returns a 6458** value greater than or equal to 3008002. Similarly, the idxFlags field 6459** was added for [version 3.9.0] ([dateof:3.9.0]). 6460** It may therefore only be used if 6461** sqlite3_libversion_number() returns a value greater than or equal to 6462** 3009000. 6463*/ 6464struct sqlite3_index_info { 6465 /* Inputs */ 6466 int nConstraint; /* Number of entries in aConstraint */ 6467 struct sqlite3_index_constraint { 6468 int iColumn; /* Column constrained. -1 for ROWID */ 6469 unsigned char op; /* Constraint operator */ 6470 unsigned char usable; /* True if this constraint is usable */ 6471 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6472 } *aConstraint; /* Table of WHERE clause constraints */ 6473 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6474 struct sqlite3_index_orderby { 6475 int iColumn; /* Column number */ 6476 unsigned char desc; /* True for DESC. False for ASC. */ 6477 } *aOrderBy; /* The ORDER BY clause */ 6478 /* Outputs */ 6479 struct sqlite3_index_constraint_usage { 6480 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6481 unsigned char omit; /* Do not code a test for this constraint */ 6482 } *aConstraintUsage; 6483 int idxNum; /* Number used to identify the index */ 6484 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6485 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6486 int orderByConsumed; /* True if output is already ordered */ 6487 double estimatedCost; /* Estimated cost of using this index */ 6488 /* Fields below are only available in SQLite 3.8.2 and later */ 6489 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6490 /* Fields below are only available in SQLite 3.9.0 and later */ 6491 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6492 /* Fields below are only available in SQLite 3.10.0 and later */ 6493 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6494}; 6495 6496/* 6497** CAPI3REF: Virtual Table Scan Flags 6498** 6499** Virtual table implementations are allowed to set the 6500** [sqlite3_index_info].idxFlags field to some combination of 6501** these bits. 6502*/ 6503#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6504 6505/* 6506** CAPI3REF: Virtual Table Constraint Operator Codes 6507** 6508** These macros defined the allowed values for the 6509** [sqlite3_index_info].aConstraint[].op field. Each value represents 6510** an operator that is part of a constraint term in the wHERE clause of 6511** a query that uses a [virtual table]. 6512*/ 6513#define SQLITE_INDEX_CONSTRAINT_EQ 2 6514#define SQLITE_INDEX_CONSTRAINT_GT 4 6515#define SQLITE_INDEX_CONSTRAINT_LE 8 6516#define SQLITE_INDEX_CONSTRAINT_LT 16 6517#define SQLITE_INDEX_CONSTRAINT_GE 32 6518#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6519#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6520#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6521#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6522#define SQLITE_INDEX_CONSTRAINT_NE 68 6523#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6524#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6525#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6526#define SQLITE_INDEX_CONSTRAINT_IS 72 6527#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6528 6529/* 6530** CAPI3REF: Register A Virtual Table Implementation 6531** METHOD: sqlite3 6532** 6533** ^These routines are used to register a new [virtual table module] name. 6534** ^Module names must be registered before 6535** creating a new [virtual table] using the module and before using a 6536** preexisting [virtual table] for the module. 6537** 6538** ^The module name is registered on the [database connection] specified 6539** by the first parameter. ^The name of the module is given by the 6540** second parameter. ^The third parameter is a pointer to 6541** the implementation of the [virtual table module]. ^The fourth 6542** parameter is an arbitrary client data pointer that is passed through 6543** into the [xCreate] and [xConnect] methods of the virtual table module 6544** when a new virtual table is be being created or reinitialized. 6545** 6546** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6547** is a pointer to a destructor for the pClientData. ^SQLite will 6548** invoke the destructor function (if it is not NULL) when SQLite 6549** no longer needs the pClientData pointer. ^The destructor will also 6550** be invoked if the call to sqlite3_create_module_v2() fails. 6551** ^The sqlite3_create_module() 6552** interface is equivalent to sqlite3_create_module_v2() with a NULL 6553** destructor. 6554*/ 6555int sqlite3_create_module( 6556 sqlite3 *db, /* SQLite connection to register module with */ 6557 const char *zName, /* Name of the module */ 6558 const sqlite3_module *p, /* Methods for the module */ 6559 void *pClientData /* Client data for xCreate/xConnect */ 6560); 6561int sqlite3_create_module_v2( 6562 sqlite3 *db, /* SQLite connection to register module with */ 6563 const char *zName, /* Name of the module */ 6564 const sqlite3_module *p, /* Methods for the module */ 6565 void *pClientData, /* Client data for xCreate/xConnect */ 6566 void(*xDestroy)(void*) /* Module destructor function */ 6567); 6568 6569/* 6570** CAPI3REF: Virtual Table Instance Object 6571** KEYWORDS: sqlite3_vtab 6572** 6573** Every [virtual table module] implementation uses a subclass 6574** of this object to describe a particular instance 6575** of the [virtual table]. Each subclass will 6576** be tailored to the specific needs of the module implementation. 6577** The purpose of this superclass is to define certain fields that are 6578** common to all module implementations. 6579** 6580** ^Virtual tables methods can set an error message by assigning a 6581** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6582** take care that any prior string is freed by a call to [sqlite3_free()] 6583** prior to assigning a new string to zErrMsg. ^After the error message 6584** is delivered up to the client application, the string will be automatically 6585** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6586*/ 6587struct sqlite3_vtab { 6588 const sqlite3_module *pModule; /* The module for this virtual table */ 6589 int nRef; /* Number of open cursors */ 6590 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6591 /* Virtual table implementations will typically add additional fields */ 6592}; 6593 6594/* 6595** CAPI3REF: Virtual Table Cursor Object 6596** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6597** 6598** Every [virtual table module] implementation uses a subclass of the 6599** following structure to describe cursors that point into the 6600** [virtual table] and are used 6601** to loop through the virtual table. Cursors are created using the 6602** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6603** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6604** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6605** of the module. Each module implementation will define 6606** the content of a cursor structure to suit its own needs. 6607** 6608** This superclass exists in order to define fields of the cursor that 6609** are common to all implementations. 6610*/ 6611struct sqlite3_vtab_cursor { 6612 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6613 /* Virtual table implementations will typically add additional fields */ 6614}; 6615 6616/* 6617** CAPI3REF: Declare The Schema Of A Virtual Table 6618** 6619** ^The [xCreate] and [xConnect] methods of a 6620** [virtual table module] call this interface 6621** to declare the format (the names and datatypes of the columns) of 6622** the virtual tables they implement. 6623*/ 6624int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6625 6626/* 6627** CAPI3REF: Overload A Function For A Virtual Table 6628** METHOD: sqlite3 6629** 6630** ^(Virtual tables can provide alternative implementations of functions 6631** using the [xFindFunction] method of the [virtual table module]. 6632** But global versions of those functions 6633** must exist in order to be overloaded.)^ 6634** 6635** ^(This API makes sure a global version of a function with a particular 6636** name and number of parameters exists. If no such function exists 6637** before this API is called, a new function is created.)^ ^The implementation 6638** of the new function always causes an exception to be thrown. So 6639** the new function is not good for anything by itself. Its only 6640** purpose is to be a placeholder function that can be overloaded 6641** by a [virtual table]. 6642*/ 6643int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6644 6645/* 6646** The interface to the virtual-table mechanism defined above (back up 6647** to a comment remarkably similar to this one) is currently considered 6648** to be experimental. The interface might change in incompatible ways. 6649** If this is a problem for you, do not use the interface at this time. 6650** 6651** When the virtual-table mechanism stabilizes, we will declare the 6652** interface fixed, support it indefinitely, and remove this comment. 6653*/ 6654 6655/* 6656** CAPI3REF: A Handle To An Open BLOB 6657** KEYWORDS: {BLOB handle} {BLOB handles} 6658** 6659** An instance of this object represents an open BLOB on which 6660** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6661** ^Objects of this type are created by [sqlite3_blob_open()] 6662** and destroyed by [sqlite3_blob_close()]. 6663** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6664** can be used to read or write small subsections of the BLOB. 6665** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6666*/ 6667typedef struct sqlite3_blob sqlite3_blob; 6668 6669/* 6670** CAPI3REF: Open A BLOB For Incremental I/O 6671** METHOD: sqlite3 6672** CONSTRUCTOR: sqlite3_blob 6673** 6674** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6675** in row iRow, column zColumn, table zTable in database zDb; 6676** in other words, the same BLOB that would be selected by: 6677** 6678** <pre> 6679** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6680** </pre>)^ 6681** 6682** ^(Parameter zDb is not the filename that contains the database, but 6683** rather the symbolic name of the database. For attached databases, this is 6684** the name that appears after the AS keyword in the [ATTACH] statement. 6685** For the main database file, the database name is "main". For TEMP 6686** tables, the database name is "temp".)^ 6687** 6688** ^If the flags parameter is non-zero, then the BLOB is opened for read 6689** and write access. ^If the flags parameter is zero, the BLOB is opened for 6690** read-only access. 6691** 6692** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6693** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6694** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6695** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6696** on *ppBlob after this function it returns. 6697** 6698** This function fails with SQLITE_ERROR if any of the following are true: 6699** <ul> 6700** <li> ^(Database zDb does not exist)^, 6701** <li> ^(Table zTable does not exist within database zDb)^, 6702** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6703** <li> ^(Column zColumn does not exist)^, 6704** <li> ^(Row iRow is not present in the table)^, 6705** <li> ^(The specified column of row iRow contains a value that is not 6706** a TEXT or BLOB value)^, 6707** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6708** constraint and the blob is being opened for read/write access)^, 6709** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6710** column zColumn is part of a [child key] definition and the blob is 6711** being opened for read/write access)^. 6712** </ul> 6713** 6714** ^Unless it returns SQLITE_MISUSE, this function sets the 6715** [database connection] error code and message accessible via 6716** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6717** 6718** A BLOB referenced by sqlite3_blob_open() may be read using the 6719** [sqlite3_blob_read()] interface and modified by using 6720** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6721** different row of the same table using the [sqlite3_blob_reopen()] 6722** interface. However, the column, table, or database of a [BLOB handle] 6723** cannot be changed after the [BLOB handle] is opened. 6724** 6725** ^(If the row that a BLOB handle points to is modified by an 6726** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6727** then the BLOB handle is marked as "expired". 6728** This is true if any column of the row is changed, even a column 6729** other than the one the BLOB handle is open on.)^ 6730** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6731** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6732** ^(Changes written into a BLOB prior to the BLOB expiring are not 6733** rolled back by the expiration of the BLOB. Such changes will eventually 6734** commit if the transaction continues to completion.)^ 6735** 6736** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6737** the opened blob. ^The size of a blob may not be changed by this 6738** interface. Use the [UPDATE] SQL command to change the size of a 6739** blob. 6740** 6741** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6742** and the built-in [zeroblob] SQL function may be used to create a 6743** zero-filled blob to read or write using the incremental-blob interface. 6744** 6745** To avoid a resource leak, every open [BLOB handle] should eventually 6746** be released by a call to [sqlite3_blob_close()]. 6747** 6748** See also: [sqlite3_blob_close()], 6749** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6750** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6751*/ 6752int sqlite3_blob_open( 6753 sqlite3*, 6754 const char *zDb, 6755 const char *zTable, 6756 const char *zColumn, 6757 sqlite3_int64 iRow, 6758 int flags, 6759 sqlite3_blob **ppBlob 6760); 6761 6762/* 6763** CAPI3REF: Move a BLOB Handle to a New Row 6764** METHOD: sqlite3_blob 6765** 6766** ^This function is used to move an existing [BLOB handle] so that it points 6767** to a different row of the same database table. ^The new row is identified 6768** by the rowid value passed as the second argument. Only the row can be 6769** changed. ^The database, table and column on which the blob handle is open 6770** remain the same. Moving an existing [BLOB handle] to a new row is 6771** faster than closing the existing handle and opening a new one. 6772** 6773** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6774** it must exist and there must be either a blob or text value stored in 6775** the nominated column.)^ ^If the new row is not present in the table, or if 6776** it does not contain a blob or text value, or if another error occurs, an 6777** SQLite error code is returned and the blob handle is considered aborted. 6778** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6779** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6780** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6781** always returns zero. 6782** 6783** ^This function sets the database handle error code and message. 6784*/ 6785int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6786 6787/* 6788** CAPI3REF: Close A BLOB Handle 6789** DESTRUCTOR: sqlite3_blob 6790** 6791** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6792** unconditionally. Even if this routine returns an error code, the 6793** handle is still closed.)^ 6794** 6795** ^If the blob handle being closed was opened for read-write access, and if 6796** the database is in auto-commit mode and there are no other open read-write 6797** blob handles or active write statements, the current transaction is 6798** committed. ^If an error occurs while committing the transaction, an error 6799** code is returned and the transaction rolled back. 6800** 6801** Calling this function with an argument that is not a NULL pointer or an 6802** open blob handle results in undefined behaviour. ^Calling this routine 6803** with a null pointer (such as would be returned by a failed call to 6804** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6805** is passed a valid open blob handle, the values returned by the 6806** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6807*/ 6808int sqlite3_blob_close(sqlite3_blob *); 6809 6810/* 6811** CAPI3REF: Return The Size Of An Open BLOB 6812** METHOD: sqlite3_blob 6813** 6814** ^Returns the size in bytes of the BLOB accessible via the 6815** successfully opened [BLOB handle] in its only argument. ^The 6816** incremental blob I/O routines can only read or overwriting existing 6817** blob content; they cannot change the size of a blob. 6818** 6819** This routine only works on a [BLOB handle] which has been created 6820** by a prior successful call to [sqlite3_blob_open()] and which has not 6821** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6822** to this routine results in undefined and probably undesirable behavior. 6823*/ 6824int sqlite3_blob_bytes(sqlite3_blob *); 6825 6826/* 6827** CAPI3REF: Read Data From A BLOB Incrementally 6828** METHOD: sqlite3_blob 6829** 6830** ^(This function is used to read data from an open [BLOB handle] into a 6831** caller-supplied buffer. N bytes of data are copied into buffer Z 6832** from the open BLOB, starting at offset iOffset.)^ 6833** 6834** ^If offset iOffset is less than N bytes from the end of the BLOB, 6835** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6836** less than zero, [SQLITE_ERROR] is returned and no data is read. 6837** ^The size of the blob (and hence the maximum value of N+iOffset) 6838** can be determined using the [sqlite3_blob_bytes()] interface. 6839** 6840** ^An attempt to read from an expired [BLOB handle] fails with an 6841** error code of [SQLITE_ABORT]. 6842** 6843** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6844** Otherwise, an [error code] or an [extended error code] is returned.)^ 6845** 6846** This routine only works on a [BLOB handle] which has been created 6847** by a prior successful call to [sqlite3_blob_open()] and which has not 6848** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6849** to this routine results in undefined and probably undesirable behavior. 6850** 6851** See also: [sqlite3_blob_write()]. 6852*/ 6853int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6854 6855/* 6856** CAPI3REF: Write Data Into A BLOB Incrementally 6857** METHOD: sqlite3_blob 6858** 6859** ^(This function is used to write data into an open [BLOB handle] from a 6860** caller-supplied buffer. N bytes of data are copied from the buffer Z 6861** into the open BLOB, starting at offset iOffset.)^ 6862** 6863** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6864** Otherwise, an [error code] or an [extended error code] is returned.)^ 6865** ^Unless SQLITE_MISUSE is returned, this function sets the 6866** [database connection] error code and message accessible via 6867** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6868** 6869** ^If the [BLOB handle] passed as the first argument was not opened for 6870** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6871** this function returns [SQLITE_READONLY]. 6872** 6873** This function may only modify the contents of the BLOB; it is 6874** not possible to increase the size of a BLOB using this API. 6875** ^If offset iOffset is less than N bytes from the end of the BLOB, 6876** [SQLITE_ERROR] is returned and no data is written. The size of the 6877** BLOB (and hence the maximum value of N+iOffset) can be determined 6878** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6879** than zero [SQLITE_ERROR] is returned and no data is written. 6880** 6881** ^An attempt to write to an expired [BLOB handle] fails with an 6882** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6883** before the [BLOB handle] expired are not rolled back by the 6884** expiration of the handle, though of course those changes might 6885** have been overwritten by the statement that expired the BLOB handle 6886** or by other independent statements. 6887** 6888** This routine only works on a [BLOB handle] which has been created 6889** by a prior successful call to [sqlite3_blob_open()] and which has not 6890** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6891** to this routine results in undefined and probably undesirable behavior. 6892** 6893** See also: [sqlite3_blob_read()]. 6894*/ 6895int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6896 6897/* 6898** CAPI3REF: Virtual File System Objects 6899** 6900** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6901** that SQLite uses to interact 6902** with the underlying operating system. Most SQLite builds come with a 6903** single default VFS that is appropriate for the host computer. 6904** New VFSes can be registered and existing VFSes can be unregistered. 6905** The following interfaces are provided. 6906** 6907** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6908** ^Names are case sensitive. 6909** ^Names are zero-terminated UTF-8 strings. 6910** ^If there is no match, a NULL pointer is returned. 6911** ^If zVfsName is NULL then the default VFS is returned. 6912** 6913** ^New VFSes are registered with sqlite3_vfs_register(). 6914** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6915** ^The same VFS can be registered multiple times without injury. 6916** ^To make an existing VFS into the default VFS, register it again 6917** with the makeDflt flag set. If two different VFSes with the 6918** same name are registered, the behavior is undefined. If a 6919** VFS is registered with a name that is NULL or an empty string, 6920** then the behavior is undefined. 6921** 6922** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6923** ^(If the default VFS is unregistered, another VFS is chosen as 6924** the default. The choice for the new VFS is arbitrary.)^ 6925*/ 6926sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6927int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6928int sqlite3_vfs_unregister(sqlite3_vfs*); 6929 6930/* 6931** CAPI3REF: Mutexes 6932** 6933** The SQLite core uses these routines for thread 6934** synchronization. Though they are intended for internal 6935** use by SQLite, code that links against SQLite is 6936** permitted to use any of these routines. 6937** 6938** The SQLite source code contains multiple implementations 6939** of these mutex routines. An appropriate implementation 6940** is selected automatically at compile-time. The following 6941** implementations are available in the SQLite core: 6942** 6943** <ul> 6944** <li> SQLITE_MUTEX_PTHREADS 6945** <li> SQLITE_MUTEX_W32 6946** <li> SQLITE_MUTEX_NOOP 6947** </ul> 6948** 6949** The SQLITE_MUTEX_NOOP implementation is a set of routines 6950** that does no real locking and is appropriate for use in 6951** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 6952** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 6953** and Windows. 6954** 6955** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 6956** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 6957** implementation is included with the library. In this case the 6958** application must supply a custom mutex implementation using the 6959** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 6960** before calling sqlite3_initialize() or any other public sqlite3_ 6961** function that calls sqlite3_initialize(). 6962** 6963** ^The sqlite3_mutex_alloc() routine allocates a new 6964** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 6965** routine returns NULL if it is unable to allocate the requested 6966** mutex. The argument to sqlite3_mutex_alloc() must one of these 6967** integer constants: 6968** 6969** <ul> 6970** <li> SQLITE_MUTEX_FAST 6971** <li> SQLITE_MUTEX_RECURSIVE 6972** <li> SQLITE_MUTEX_STATIC_MASTER 6973** <li> SQLITE_MUTEX_STATIC_MEM 6974** <li> SQLITE_MUTEX_STATIC_OPEN 6975** <li> SQLITE_MUTEX_STATIC_PRNG 6976** <li> SQLITE_MUTEX_STATIC_LRU 6977** <li> SQLITE_MUTEX_STATIC_PMEM 6978** <li> SQLITE_MUTEX_STATIC_APP1 6979** <li> SQLITE_MUTEX_STATIC_APP2 6980** <li> SQLITE_MUTEX_STATIC_APP3 6981** <li> SQLITE_MUTEX_STATIC_VFS1 6982** <li> SQLITE_MUTEX_STATIC_VFS2 6983** <li> SQLITE_MUTEX_STATIC_VFS3 6984** </ul> 6985** 6986** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 6987** cause sqlite3_mutex_alloc() to create 6988** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 6989** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 6990** The mutex implementation does not need to make a distinction 6991** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 6992** not want to. SQLite will only request a recursive mutex in 6993** cases where it really needs one. If a faster non-recursive mutex 6994** implementation is available on the host platform, the mutex subsystem 6995** might return such a mutex in response to SQLITE_MUTEX_FAST. 6996** 6997** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 6998** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 6999** a pointer to a static preexisting mutex. ^Nine static mutexes are 7000** used by the current version of SQLite. Future versions of SQLite 7001** may add additional static mutexes. Static mutexes are for internal 7002** use by SQLite only. Applications that use SQLite mutexes should 7003** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7004** SQLITE_MUTEX_RECURSIVE. 7005** 7006** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7007** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7008** returns a different mutex on every call. ^For the static 7009** mutex types, the same mutex is returned on every call that has 7010** the same type number. 7011** 7012** ^The sqlite3_mutex_free() routine deallocates a previously 7013** allocated dynamic mutex. Attempting to deallocate a static 7014** mutex results in undefined behavior. 7015** 7016** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7017** to enter a mutex. ^If another thread is already within the mutex, 7018** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7019** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7020** upon successful entry. ^(Mutexes created using 7021** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7022** In such cases, the 7023** mutex must be exited an equal number of times before another thread 7024** can enter.)^ If the same thread tries to enter any mutex other 7025** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7026** 7027** ^(Some systems (for example, Windows 95) do not support the operation 7028** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7029** will always return SQLITE_BUSY. The SQLite core only ever uses 7030** sqlite3_mutex_try() as an optimization so this is acceptable 7031** behavior.)^ 7032** 7033** ^The sqlite3_mutex_leave() routine exits a mutex that was 7034** previously entered by the same thread. The behavior 7035** is undefined if the mutex is not currently entered by the 7036** calling thread or is not currently allocated. 7037** 7038** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7039** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7040** behave as no-ops. 7041** 7042** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7043*/ 7044sqlite3_mutex *sqlite3_mutex_alloc(int); 7045void sqlite3_mutex_free(sqlite3_mutex*); 7046void sqlite3_mutex_enter(sqlite3_mutex*); 7047int sqlite3_mutex_try(sqlite3_mutex*); 7048void sqlite3_mutex_leave(sqlite3_mutex*); 7049 7050/* 7051** CAPI3REF: Mutex Methods Object 7052** 7053** An instance of this structure defines the low-level routines 7054** used to allocate and use mutexes. 7055** 7056** Usually, the default mutex implementations provided by SQLite are 7057** sufficient, however the application has the option of substituting a custom 7058** implementation for specialized deployments or systems for which SQLite 7059** does not provide a suitable implementation. In this case, the application 7060** creates and populates an instance of this structure to pass 7061** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7062** Additionally, an instance of this structure can be used as an 7063** output variable when querying the system for the current mutex 7064** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7065** 7066** ^The xMutexInit method defined by this structure is invoked as 7067** part of system initialization by the sqlite3_initialize() function. 7068** ^The xMutexInit routine is called by SQLite exactly once for each 7069** effective call to [sqlite3_initialize()]. 7070** 7071** ^The xMutexEnd method defined by this structure is invoked as 7072** part of system shutdown by the sqlite3_shutdown() function. The 7073** implementation of this method is expected to release all outstanding 7074** resources obtained by the mutex methods implementation, especially 7075** those obtained by the xMutexInit method. ^The xMutexEnd() 7076** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7077** 7078** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7079** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7080** xMutexNotheld) implement the following interfaces (respectively): 7081** 7082** <ul> 7083** <li> [sqlite3_mutex_alloc()] </li> 7084** <li> [sqlite3_mutex_free()] </li> 7085** <li> [sqlite3_mutex_enter()] </li> 7086** <li> [sqlite3_mutex_try()] </li> 7087** <li> [sqlite3_mutex_leave()] </li> 7088** <li> [sqlite3_mutex_held()] </li> 7089** <li> [sqlite3_mutex_notheld()] </li> 7090** </ul>)^ 7091** 7092** The only difference is that the public sqlite3_XXX functions enumerated 7093** above silently ignore any invocations that pass a NULL pointer instead 7094** of a valid mutex handle. The implementations of the methods defined 7095** by this structure are not required to handle this case, the results 7096** of passing a NULL pointer instead of a valid mutex handle are undefined 7097** (i.e. it is acceptable to provide an implementation that segfaults if 7098** it is passed a NULL pointer). 7099** 7100** The xMutexInit() method must be threadsafe. It must be harmless to 7101** invoke xMutexInit() multiple times within the same process and without 7102** intervening calls to xMutexEnd(). Second and subsequent calls to 7103** xMutexInit() must be no-ops. 7104** 7105** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7106** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7107** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7108** memory allocation for a fast or recursive mutex. 7109** 7110** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7111** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7112** If xMutexInit fails in any way, it is expected to clean up after itself 7113** prior to returning. 7114*/ 7115typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7116struct sqlite3_mutex_methods { 7117 int (*xMutexInit)(void); 7118 int (*xMutexEnd)(void); 7119 sqlite3_mutex *(*xMutexAlloc)(int); 7120 void (*xMutexFree)(sqlite3_mutex *); 7121 void (*xMutexEnter)(sqlite3_mutex *); 7122 int (*xMutexTry)(sqlite3_mutex *); 7123 void (*xMutexLeave)(sqlite3_mutex *); 7124 int (*xMutexHeld)(sqlite3_mutex *); 7125 int (*xMutexNotheld)(sqlite3_mutex *); 7126}; 7127 7128/* 7129** CAPI3REF: Mutex Verification Routines 7130** 7131** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7132** are intended for use inside assert() statements. The SQLite core 7133** never uses these routines except inside an assert() and applications 7134** are advised to follow the lead of the core. The SQLite core only 7135** provides implementations for these routines when it is compiled 7136** with the SQLITE_DEBUG flag. External mutex implementations 7137** are only required to provide these routines if SQLITE_DEBUG is 7138** defined and if NDEBUG is not defined. 7139** 7140** These routines should return true if the mutex in their argument 7141** is held or not held, respectively, by the calling thread. 7142** 7143** The implementation is not required to provide versions of these 7144** routines that actually work. If the implementation does not provide working 7145** versions of these routines, it should at least provide stubs that always 7146** return true so that one does not get spurious assertion failures. 7147** 7148** If the argument to sqlite3_mutex_held() is a NULL pointer then 7149** the routine should return 1. This seems counter-intuitive since 7150** clearly the mutex cannot be held if it does not exist. But 7151** the reason the mutex does not exist is because the build is not 7152** using mutexes. And we do not want the assert() containing the 7153** call to sqlite3_mutex_held() to fail, so a non-zero return is 7154** the appropriate thing to do. The sqlite3_mutex_notheld() 7155** interface should also return 1 when given a NULL pointer. 7156*/ 7157#ifndef NDEBUG 7158int sqlite3_mutex_held(sqlite3_mutex*); 7159int sqlite3_mutex_notheld(sqlite3_mutex*); 7160#endif 7161 7162/* 7163** CAPI3REF: Mutex Types 7164** 7165** The [sqlite3_mutex_alloc()] interface takes a single argument 7166** which is one of these integer constants. 7167** 7168** The set of static mutexes may change from one SQLite release to the 7169** next. Applications that override the built-in mutex logic must be 7170** prepared to accommodate additional static mutexes. 7171*/ 7172#define SQLITE_MUTEX_FAST 0 7173#define SQLITE_MUTEX_RECURSIVE 1 7174#define SQLITE_MUTEX_STATIC_MASTER 2 7175#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7176#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7177#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7178#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7179#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7180#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7181#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7182#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7183#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7184#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7185#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7186#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7187#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7188 7189/* 7190** CAPI3REF: Retrieve the mutex for a database connection 7191** METHOD: sqlite3 7192** 7193** ^This interface returns a pointer the [sqlite3_mutex] object that 7194** serializes access to the [database connection] given in the argument 7195** when the [threading mode] is Serialized. 7196** ^If the [threading mode] is Single-thread or Multi-thread then this 7197** routine returns a NULL pointer. 7198*/ 7199sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7200 7201/* 7202** CAPI3REF: Low-Level Control Of Database Files 7203** METHOD: sqlite3 7204** KEYWORDS: {file control} 7205** 7206** ^The [sqlite3_file_control()] interface makes a direct call to the 7207** xFileControl method for the [sqlite3_io_methods] object associated 7208** with a particular database identified by the second argument. ^The 7209** name of the database is "main" for the main database or "temp" for the 7210** TEMP database, or the name that appears after the AS keyword for 7211** databases that are added using the [ATTACH] SQL command. 7212** ^A NULL pointer can be used in place of "main" to refer to the 7213** main database file. 7214** ^The third and fourth parameters to this routine 7215** are passed directly through to the second and third parameters of 7216** the xFileControl method. ^The return value of the xFileControl 7217** method becomes the return value of this routine. 7218** 7219** A few opcodes for [sqlite3_file_control()] are handled directly 7220** by the SQLite core and never invoke the 7221** sqlite3_io_methods.xFileControl method. 7222** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7223** a pointer to the underlying [sqlite3_file] object to be written into 7224** the space pointed to by the 4th parameter. The 7225** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7226** the [sqlite3_file] object associated with the journal file instead of 7227** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7228** a pointer to the underlying [sqlite3_vfs] object for the file. 7229** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7230** from the pager. 7231** 7232** ^If the second parameter (zDbName) does not match the name of any 7233** open database file, then SQLITE_ERROR is returned. ^This error 7234** code is not remembered and will not be recalled by [sqlite3_errcode()] 7235** or [sqlite3_errmsg()]. The underlying xFileControl method might 7236** also return SQLITE_ERROR. There is no way to distinguish between 7237** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7238** xFileControl method. 7239** 7240** See also: [file control opcodes] 7241*/ 7242int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7243 7244/* 7245** CAPI3REF: Testing Interface 7246** 7247** ^The sqlite3_test_control() interface is used to read out internal 7248** state of SQLite and to inject faults into SQLite for testing 7249** purposes. ^The first parameter is an operation code that determines 7250** the number, meaning, and operation of all subsequent parameters. 7251** 7252** This interface is not for use by applications. It exists solely 7253** for verifying the correct operation of the SQLite library. Depending 7254** on how the SQLite library is compiled, this interface might not exist. 7255** 7256** The details of the operation codes, their meanings, the parameters 7257** they take, and what they do are all subject to change without notice. 7258** Unlike most of the SQLite API, this function is not guaranteed to 7259** operate consistently from one release to the next. 7260*/ 7261int sqlite3_test_control(int op, ...); 7262 7263/* 7264** CAPI3REF: Testing Interface Operation Codes 7265** 7266** These constants are the valid operation code parameters used 7267** as the first argument to [sqlite3_test_control()]. 7268** 7269** These parameters and their meanings are subject to change 7270** without notice. These values are for testing purposes only. 7271** Applications should not use any of these parameters or the 7272** [sqlite3_test_control()] interface. 7273*/ 7274#define SQLITE_TESTCTRL_FIRST 5 7275#define SQLITE_TESTCTRL_PRNG_SAVE 5 7276#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7277#define SQLITE_TESTCTRL_PRNG_RESET 7 7278#define SQLITE_TESTCTRL_BITVEC_TEST 8 7279#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7280#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7281#define SQLITE_TESTCTRL_PENDING_BYTE 11 7282#define SQLITE_TESTCTRL_ASSERT 12 7283#define SQLITE_TESTCTRL_ALWAYS 13 7284#define SQLITE_TESTCTRL_RESERVE 14 7285#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7286#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7287#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7288#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7289#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7290#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7291#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7292#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7293#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7294#define SQLITE_TESTCTRL_BYTEORDER 22 7295#define SQLITE_TESTCTRL_ISINIT 23 7296#define SQLITE_TESTCTRL_SORTER_MMAP 24 7297#define SQLITE_TESTCTRL_IMPOSTER 25 7298#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7299#define SQLITE_TESTCTRL_LAST 26 /* Largest TESTCTRL */ 7300 7301/* 7302** CAPI3REF: SQL Keyword Checking 7303** 7304** These routines provide access to the set of SQL language keywords 7305** recognized by SQLite. Applications can uses these routines to determine 7306** whether or not a specific identifier needs to be escaped (for example, 7307** by enclosing in double-quotes) so as not to confuse the parser. 7308** 7309** The sqlite3_keyword_count() interface returns the number of distinct 7310** keywords understood by SQLite. 7311** 7312** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7313** makes *Z point to that keyword expressed as UTF8 and writes the number 7314** of bytes in the keyword into *L. The string that *Z points to is not 7315** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7316** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7317** or L are NULL or invalid pointers then calls to 7318** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7319** 7320** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7321** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7322** if it is and zero if not. 7323** 7324** The parser used by SQLite is forgiving. It is often possible to use 7325** a keyword as an identifier as long as such use does not result in a 7326** parsing ambiguity. For example, the statement 7327** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7328** creates a new table named "BEGIN" with three columns named 7329** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7330** using keywords as identifiers. Common techniques used to avoid keyword 7331** name collisions include: 7332** <ul> 7333** <li> Put all identifier names inside double-quotes. This is the official 7334** SQL way to escape identifier names. 7335** <li> Put identifier names inside [...]. This is not standard SQL, 7336** but it is what SQL Server does and so lots of programmers use this 7337** technique. 7338** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7339** with "Z". 7340** <li> Include a digit somewhere in every identifier name. 7341** </ul> 7342** 7343** Note that the number of keywords understood by SQLite can depend on 7344** compile-time options. For example, "VACUUM" is not a keyword if 7345** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7346** new keywords may be added to future releases of SQLite. 7347*/ 7348int sqlite3_keyword_count(void); 7349int sqlite3_keyword_name(int,const char**,int*); 7350int sqlite3_keyword_check(const char*,int); 7351 7352/* 7353** CAPI3REF: Dynamic String Object 7354** KEYWORDS: {dynamic string} 7355** 7356** An instance of the sqlite3_str object contains a dynamically-sized 7357** string under construction. 7358** 7359** The lifecycle of an sqlite3_str object is as follows: 7360** <ol> 7361** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7362** <li> ^Text is appended to the sqlite3_str object using various 7363** methods, such as [sqlite3_str_appendf()]. 7364** <li> ^The sqlite3_str object is destroyed and the string it created 7365** is returned using the [sqlite3_str_finish()] interface. 7366** </ol> 7367*/ 7368typedef struct sqlite3_str sqlite3_str; 7369 7370/* 7371** CAPI3REF: Create A New Dynamic String Object 7372** CONSTRUCTOR: sqlite3_str 7373** 7374** ^The [sqlite3_str_new(D)] interface allocates and initializes 7375** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7376** [sqlite3_str_new()] must be freed by a subsequent call to 7377** [sqlite3_str_finish(X)]. 7378** 7379** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7380** valid [sqlite3_str] object, though in the event of an out-of-memory 7381** error the returned object might be a special singleton that will 7382** silently reject new text, always return SQLITE_NOMEM from 7383** [sqlite3_str_errcode()], always return 0 for 7384** [sqlite3_str_length()], and always return NULL from 7385** [sqlite3_str_finish(X)]. It is always safe to use the value 7386** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7387** to any of the other [sqlite3_str] methods. 7388** 7389** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7390** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7391** length of the string contained in the [sqlite3_str] object will be 7392** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7393** of [SQLITE_MAX_LENGTH]. 7394*/ 7395sqlite3_str *sqlite3_str_new(sqlite3*); 7396 7397/* 7398** CAPI3REF: Finalize A Dynamic String 7399** DESTRUCTOR: sqlite3_str 7400** 7401** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7402** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7403** that contains the constructed string. The calling application should 7404** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7405** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7406** errors were encountered during construction of the string. ^The 7407** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7408** string in [sqlite3_str] object X is zero bytes long. 7409*/ 7410char *sqlite3_str_finish(sqlite3_str*); 7411 7412/* 7413** CAPI3REF: Add Content To A Dynamic String 7414** METHOD: sqlite3_str 7415** 7416** These interfaces add content to an sqlite3_str object previously obtained 7417** from [sqlite3_str_new()]. 7418** 7419** ^The [sqlite3_str_appendf(X,F,...)] and 7420** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7421** functionality of SQLite to append formatted text onto the end of 7422** [sqlite3_str] object X. 7423** 7424** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7425** onto the end of the [sqlite3_str] object X. N must be non-negative. 7426** S must contain at least N non-zero bytes of content. To append a 7427** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7428** method instead. 7429** 7430** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7431** zero-terminated string S onto the end of [sqlite3_str] object X. 7432** 7433** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7434** single-byte character C onto the end of [sqlite3_str] object X. 7435** ^This method can be used, for example, to add whitespace indentation. 7436** 7437** ^The [sqlite3_str_reset(X)] method resets the string under construction 7438** inside [sqlite3_str] object X back to zero bytes in length. 7439** 7440** These methods do not return a result code. ^If an error occurs, that fact 7441** is recorded in the [sqlite3_str] object and can be recovered by a 7442** subsequent call to [sqlite3_str_errcode(X)]. 7443*/ 7444void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7445void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7446void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7447void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7448void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7449void sqlite3_str_reset(sqlite3_str*); 7450 7451/* 7452** CAPI3REF: Status Of A Dynamic String 7453** METHOD: sqlite3_str 7454** 7455** These interfaces return the current status of an [sqlite3_str] object. 7456** 7457** ^If any prior errors have occurred while constructing the dynamic string 7458** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7459** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7460** [SQLITE_NOMEM] following any out-of-memory error, or 7461** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7462** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7463** 7464** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7465** of the dynamic string under construction in [sqlite3_str] object X. 7466** ^The length returned by [sqlite3_str_length(X)] does not include the 7467** zero-termination byte. 7468** 7469** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7470** content of the dynamic string under construction in X. The value 7471** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7472** and might be freed or altered by any subsequent method on the same 7473** [sqlite3_str] object. Applications must not used the pointer returned 7474** [sqlite3_str_value(X)] after any subsequent method call on the same 7475** object. ^Applications may change the content of the string returned 7476** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7477** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7478** write any byte after any subsequent sqlite3_str method call. 7479*/ 7480int sqlite3_str_errcode(sqlite3_str*); 7481int sqlite3_str_length(sqlite3_str*); 7482char *sqlite3_str_value(sqlite3_str*); 7483 7484/* 7485** CAPI3REF: SQLite Runtime Status 7486** 7487** ^These interfaces are used to retrieve runtime status information 7488** about the performance of SQLite, and optionally to reset various 7489** highwater marks. ^The first argument is an integer code for 7490** the specific parameter to measure. ^(Recognized integer codes 7491** are of the form [status parameters | SQLITE_STATUS_...].)^ 7492** ^The current value of the parameter is returned into *pCurrent. 7493** ^The highest recorded value is returned in *pHighwater. ^If the 7494** resetFlag is true, then the highest record value is reset after 7495** *pHighwater is written. ^(Some parameters do not record the highest 7496** value. For those parameters 7497** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7498** ^(Other parameters record only the highwater mark and not the current 7499** value. For these latter parameters nothing is written into *pCurrent.)^ 7500** 7501** ^The sqlite3_status() and sqlite3_status64() routines return 7502** SQLITE_OK on success and a non-zero [error code] on failure. 7503** 7504** If either the current value or the highwater mark is too large to 7505** be represented by a 32-bit integer, then the values returned by 7506** sqlite3_status() are undefined. 7507** 7508** See also: [sqlite3_db_status()] 7509*/ 7510int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7511int sqlite3_status64( 7512 int op, 7513 sqlite3_int64 *pCurrent, 7514 sqlite3_int64 *pHighwater, 7515 int resetFlag 7516); 7517 7518 7519/* 7520** CAPI3REF: Status Parameters 7521** KEYWORDS: {status parameters} 7522** 7523** These integer constants designate various run-time status parameters 7524** that can be returned by [sqlite3_status()]. 7525** 7526** <dl> 7527** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7528** <dd>This parameter is the current amount of memory checked out 7529** using [sqlite3_malloc()], either directly or indirectly. The 7530** figure includes calls made to [sqlite3_malloc()] by the application 7531** and internal memory usage by the SQLite library. Auxiliary page-cache 7532** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7533** this parameter. The amount returned is the sum of the allocation 7534** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7535** 7536** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7537** <dd>This parameter records the largest memory allocation request 7538** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7539** internal equivalents). Only the value returned in the 7540** *pHighwater parameter to [sqlite3_status()] is of interest. 7541** The value written into the *pCurrent parameter is undefined.</dd>)^ 7542** 7543** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7544** <dd>This parameter records the number of separate memory allocations 7545** currently checked out.</dd>)^ 7546** 7547** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7548** <dd>This parameter returns the number of pages used out of the 7549** [pagecache memory allocator] that was configured using 7550** [SQLITE_CONFIG_PAGECACHE]. The 7551** value returned is in pages, not in bytes.</dd>)^ 7552** 7553** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7554** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7555** <dd>This parameter returns the number of bytes of page cache 7556** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7557** buffer and where forced to overflow to [sqlite3_malloc()]. The 7558** returned value includes allocations that overflowed because they 7559** where too large (they were larger than the "sz" parameter to 7560** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7561** no space was left in the page cache.</dd>)^ 7562** 7563** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7564** <dd>This parameter records the largest memory allocation request 7565** handed to [pagecache memory allocator]. Only the value returned in the 7566** *pHighwater parameter to [sqlite3_status()] is of interest. 7567** The value written into the *pCurrent parameter is undefined.</dd>)^ 7568** 7569** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7570** <dd>No longer used.</dd> 7571** 7572** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7573** <dd>No longer used.</dd> 7574** 7575** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7576** <dd>No longer used.</dd> 7577** 7578** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7579** <dd>The *pHighwater parameter records the deepest parser stack. 7580** The *pCurrent value is undefined. The *pHighwater value is only 7581** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7582** </dl> 7583** 7584** New status parameters may be added from time to time. 7585*/ 7586#define SQLITE_STATUS_MEMORY_USED 0 7587#define SQLITE_STATUS_PAGECACHE_USED 1 7588#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7589#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7590#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7591#define SQLITE_STATUS_MALLOC_SIZE 5 7592#define SQLITE_STATUS_PARSER_STACK 6 7593#define SQLITE_STATUS_PAGECACHE_SIZE 7 7594#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7595#define SQLITE_STATUS_MALLOC_COUNT 9 7596 7597/* 7598** CAPI3REF: Database Connection Status 7599** METHOD: sqlite3 7600** 7601** ^This interface is used to retrieve runtime status information 7602** about a single [database connection]. ^The first argument is the 7603** database connection object to be interrogated. ^The second argument 7604** is an integer constant, taken from the set of 7605** [SQLITE_DBSTATUS options], that 7606** determines the parameter to interrogate. The set of 7607** [SQLITE_DBSTATUS options] is likely 7608** to grow in future releases of SQLite. 7609** 7610** ^The current value of the requested parameter is written into *pCur 7611** and the highest instantaneous value is written into *pHiwtr. ^If 7612** the resetFlg is true, then the highest instantaneous value is 7613** reset back down to the current value. 7614** 7615** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7616** non-zero [error code] on failure. 7617** 7618** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7619*/ 7620int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7621 7622/* 7623** CAPI3REF: Status Parameters for database connections 7624** KEYWORDS: {SQLITE_DBSTATUS options} 7625** 7626** These constants are the available integer "verbs" that can be passed as 7627** the second argument to the [sqlite3_db_status()] interface. 7628** 7629** New verbs may be added in future releases of SQLite. Existing verbs 7630** might be discontinued. Applications should check the return code from 7631** [sqlite3_db_status()] to make sure that the call worked. 7632** The [sqlite3_db_status()] interface will return a non-zero error code 7633** if a discontinued or unsupported verb is invoked. 7634** 7635** <dl> 7636** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7637** <dd>This parameter returns the number of lookaside memory slots currently 7638** checked out.</dd>)^ 7639** 7640** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7641** <dd>This parameter returns the number malloc attempts that were 7642** satisfied using lookaside memory. Only the high-water value is meaningful; 7643** the current value is always zero.)^ 7644** 7645** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7646** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7647** <dd>This parameter returns the number malloc attempts that might have 7648** been satisfied using lookaside memory but failed due to the amount of 7649** memory requested being larger than the lookaside slot size. 7650** Only the high-water value is meaningful; 7651** the current value is always zero.)^ 7652** 7653** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7654** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7655** <dd>This parameter returns the number malloc attempts that might have 7656** been satisfied using lookaside memory but failed due to all lookaside 7657** memory already being in use. 7658** Only the high-water value is meaningful; 7659** the current value is always zero.)^ 7660** 7661** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7662** <dd>This parameter returns the approximate number of bytes of heap 7663** memory used by all pager caches associated with the database connection.)^ 7664** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7665** 7666** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7667** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7668** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7669** pager cache is shared between two or more connections the bytes of heap 7670** memory used by that pager cache is divided evenly between the attached 7671** connections.)^ In other words, if none of the pager caches associated 7672** with the database connection are shared, this request returns the same 7673** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7674** shared, the value returned by this call will be smaller than that returned 7675** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7676** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7677** 7678** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7679** <dd>This parameter returns the approximate number of bytes of heap 7680** memory used to store the schema for all databases associated 7681** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7682** ^The full amount of memory used by the schemas is reported, even if the 7683** schema memory is shared with other database connections due to 7684** [shared cache mode] being enabled. 7685** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7686** 7687** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7688** <dd>This parameter returns the approximate number of bytes of heap 7689** and lookaside memory used by all prepared statements associated with 7690** the database connection.)^ 7691** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7692** </dd> 7693** 7694** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7695** <dd>This parameter returns the number of pager cache hits that have 7696** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7697** is always 0. 7698** </dd> 7699** 7700** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7701** <dd>This parameter returns the number of pager cache misses that have 7702** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7703** is always 0. 7704** </dd> 7705** 7706** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7707** <dd>This parameter returns the number of dirty cache entries that have 7708** been written to disk. Specifically, the number of pages written to the 7709** wal file in wal mode databases, or the number of pages written to the 7710** database file in rollback mode databases. Any pages written as part of 7711** transaction rollback or database recovery operations are not included. 7712** If an IO or other error occurs while writing a page to disk, the effect 7713** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7714** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7715** </dd> 7716** 7717** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 7718** <dd>This parameter returns the number of dirty cache entries that have 7719** been written to disk in the middle of a transaction due to the page 7720** cache overflowing. Transactions are more efficient if they are written 7721** to disk all at once. When pages spill mid-transaction, that introduces 7722** additional overhead. This parameter can be used help identify 7723** inefficiencies that can be resolve by increasing the cache size. 7724** </dd> 7725** 7726** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7727** <dd>This parameter returns zero for the current value if and only if 7728** all foreign key constraints (deferred or immediate) have been 7729** resolved.)^ ^The highwater mark is always 0. 7730** </dd> 7731** </dl> 7732*/ 7733#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7734#define SQLITE_DBSTATUS_CACHE_USED 1 7735#define SQLITE_DBSTATUS_SCHEMA_USED 2 7736#define SQLITE_DBSTATUS_STMT_USED 3 7737#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7738#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7739#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7740#define SQLITE_DBSTATUS_CACHE_HIT 7 7741#define SQLITE_DBSTATUS_CACHE_MISS 8 7742#define SQLITE_DBSTATUS_CACHE_WRITE 9 7743#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7744#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7745#define SQLITE_DBSTATUS_CACHE_SPILL 12 7746#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 7747 7748 7749/* 7750** CAPI3REF: Prepared Statement Status 7751** METHOD: sqlite3_stmt 7752** 7753** ^(Each prepared statement maintains various 7754** [SQLITE_STMTSTATUS counters] that measure the number 7755** of times it has performed specific operations.)^ These counters can 7756** be used to monitor the performance characteristics of the prepared 7757** statements. For example, if the number of table steps greatly exceeds 7758** the number of table searches or result rows, that would tend to indicate 7759** that the prepared statement is using a full table scan rather than 7760** an index. 7761** 7762** ^(This interface is used to retrieve and reset counter values from 7763** a [prepared statement]. The first argument is the prepared statement 7764** object to be interrogated. The second argument 7765** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7766** to be interrogated.)^ 7767** ^The current value of the requested counter is returned. 7768** ^If the resetFlg is true, then the counter is reset to zero after this 7769** interface call returns. 7770** 7771** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7772*/ 7773int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7774 7775/* 7776** CAPI3REF: Status Parameters for prepared statements 7777** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7778** 7779** These preprocessor macros define integer codes that name counter 7780** values associated with the [sqlite3_stmt_status()] interface. 7781** The meanings of the various counters are as follows: 7782** 7783** <dl> 7784** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7785** <dd>^This is the number of times that SQLite has stepped forward in 7786** a table as part of a full table scan. Large numbers for this counter 7787** may indicate opportunities for performance improvement through 7788** careful use of indices.</dd> 7789** 7790** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7791** <dd>^This is the number of sort operations that have occurred. 7792** A non-zero value in this counter may indicate an opportunity to 7793** improvement performance through careful use of indices.</dd> 7794** 7795** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7796** <dd>^This is the number of rows inserted into transient indices that 7797** were created automatically in order to help joins run faster. 7798** A non-zero value in this counter may indicate an opportunity to 7799** improvement performance by adding permanent indices that do not 7800** need to be reinitialized each time the statement is run.</dd> 7801** 7802** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7803** <dd>^This is the number of virtual machine operations executed 7804** by the prepared statement if that number is less than or equal 7805** to 2147483647. The number of virtual machine operations can be 7806** used as a proxy for the total work done by the prepared statement. 7807** If the number of virtual machine operations exceeds 2147483647 7808** then the value returned by this statement status code is undefined. 7809** 7810** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7811** <dd>^This is the number of times that the prepare statement has been 7812** automatically regenerated due to schema changes or change to 7813** [bound parameters] that might affect the query plan. 7814** 7815** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7816** <dd>^This is the number of times that the prepared statement has 7817** been run. A single "run" for the purposes of this counter is one 7818** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7819** The counter is incremented on the first [sqlite3_step()] call of each 7820** cycle. 7821** 7822** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7823** <dd>^This is the approximate number of bytes of heap memory 7824** used to store the prepared statement. ^This value is not actually 7825** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7826** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7827** </dd> 7828** </dl> 7829*/ 7830#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7831#define SQLITE_STMTSTATUS_SORT 2 7832#define SQLITE_STMTSTATUS_AUTOINDEX 3 7833#define SQLITE_STMTSTATUS_VM_STEP 4 7834#define SQLITE_STMTSTATUS_REPREPARE 5 7835#define SQLITE_STMTSTATUS_RUN 6 7836#define SQLITE_STMTSTATUS_MEMUSED 99 7837 7838/* 7839** CAPI3REF: Custom Page Cache Object 7840** 7841** The sqlite3_pcache type is opaque. It is implemented by 7842** the pluggable module. The SQLite core has no knowledge of 7843** its size or internal structure and never deals with the 7844** sqlite3_pcache object except by holding and passing pointers 7845** to the object. 7846** 7847** See [sqlite3_pcache_methods2] for additional information. 7848*/ 7849typedef struct sqlite3_pcache sqlite3_pcache; 7850 7851/* 7852** CAPI3REF: Custom Page Cache Object 7853** 7854** The sqlite3_pcache_page object represents a single page in the 7855** page cache. The page cache will allocate instances of this 7856** object. Various methods of the page cache use pointers to instances 7857** of this object as parameters or as their return value. 7858** 7859** See [sqlite3_pcache_methods2] for additional information. 7860*/ 7861typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7862struct sqlite3_pcache_page { 7863 void *pBuf; /* The content of the page */ 7864 void *pExtra; /* Extra information associated with the page */ 7865}; 7866 7867/* 7868** CAPI3REF: Application Defined Page Cache. 7869** KEYWORDS: {page cache} 7870** 7871** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7872** register an alternative page cache implementation by passing in an 7873** instance of the sqlite3_pcache_methods2 structure.)^ 7874** In many applications, most of the heap memory allocated by 7875** SQLite is used for the page cache. 7876** By implementing a 7877** custom page cache using this API, an application can better control 7878** the amount of memory consumed by SQLite, the way in which 7879** that memory is allocated and released, and the policies used to 7880** determine exactly which parts of a database file are cached and for 7881** how long. 7882** 7883** The alternative page cache mechanism is an 7884** extreme measure that is only needed by the most demanding applications. 7885** The built-in page cache is recommended for most uses. 7886** 7887** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7888** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7889** the application may discard the parameter after the call to 7890** [sqlite3_config()] returns.)^ 7891** 7892** [[the xInit() page cache method]] 7893** ^(The xInit() method is called once for each effective 7894** call to [sqlite3_initialize()])^ 7895** (usually only once during the lifetime of the process). ^(The xInit() 7896** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7897** The intent of the xInit() method is to set up global data structures 7898** required by the custom page cache implementation. 7899** ^(If the xInit() method is NULL, then the 7900** built-in default page cache is used instead of the application defined 7901** page cache.)^ 7902** 7903** [[the xShutdown() page cache method]] 7904** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7905** It can be used to clean up 7906** any outstanding resources before process shutdown, if required. 7907** ^The xShutdown() method may be NULL. 7908** 7909** ^SQLite automatically serializes calls to the xInit method, 7910** so the xInit method need not be threadsafe. ^The 7911** xShutdown method is only called from [sqlite3_shutdown()] so it does 7912** not need to be threadsafe either. All other methods must be threadsafe 7913** in multithreaded applications. 7914** 7915** ^SQLite will never invoke xInit() more than once without an intervening 7916** call to xShutdown(). 7917** 7918** [[the xCreate() page cache methods]] 7919** ^SQLite invokes the xCreate() method to construct a new cache instance. 7920** SQLite will typically create one cache instance for each open database file, 7921** though this is not guaranteed. ^The 7922** first parameter, szPage, is the size in bytes of the pages that must 7923** be allocated by the cache. ^szPage will always a power of two. ^The 7924** second parameter szExtra is a number of bytes of extra storage 7925** associated with each page cache entry. ^The szExtra parameter will 7926** a number less than 250. SQLite will use the 7927** extra szExtra bytes on each page to store metadata about the underlying 7928** database page on disk. The value passed into szExtra depends 7929** on the SQLite version, the target platform, and how SQLite was compiled. 7930** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7931** created will be used to cache database pages of a file stored on disk, or 7932** false if it is used for an in-memory database. The cache implementation 7933** does not have to do anything special based with the value of bPurgeable; 7934** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7935** never invoke xUnpin() except to deliberately delete a page. 7936** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 7937** false will always have the "discard" flag set to true. 7938** ^Hence, a cache created with bPurgeable false will 7939** never contain any unpinned pages. 7940** 7941** [[the xCachesize() page cache method]] 7942** ^(The xCachesize() method may be called at any time by SQLite to set the 7943** suggested maximum cache-size (number of pages stored by) the cache 7944** instance passed as the first argument. This is the value configured using 7945** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 7946** parameter, the implementation is not required to do anything with this 7947** value; it is advisory only. 7948** 7949** [[the xPagecount() page cache methods]] 7950** The xPagecount() method must return the number of pages currently 7951** stored in the cache, both pinned and unpinned. 7952** 7953** [[the xFetch() page cache methods]] 7954** The xFetch() method locates a page in the cache and returns a pointer to 7955** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 7956** The pBuf element of the returned sqlite3_pcache_page object will be a 7957** pointer to a buffer of szPage bytes used to store the content of a 7958** single database page. The pExtra element of sqlite3_pcache_page will be 7959** a pointer to the szExtra bytes of extra storage that SQLite has requested 7960** for each entry in the page cache. 7961** 7962** The page to be fetched is determined by the key. ^The minimum key value 7963** is 1. After it has been retrieved using xFetch, the page is considered 7964** to be "pinned". 7965** 7966** If the requested page is already in the page cache, then the page cache 7967** implementation must return a pointer to the page buffer with its content 7968** intact. If the requested page is not already in the cache, then the 7969** cache implementation should use the value of the createFlag 7970** parameter to help it determined what action to take: 7971** 7972** <table border=1 width=85% align=center> 7973** <tr><th> createFlag <th> Behavior when page is not already in cache 7974** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 7975** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 7976** Otherwise return NULL. 7977** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 7978** NULL if allocating a new page is effectively impossible. 7979** </table> 7980** 7981** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 7982** will only use a createFlag of 2 after a prior call with a createFlag of 1 7983** failed.)^ In between the to xFetch() calls, SQLite may 7984** attempt to unpin one or more cache pages by spilling the content of 7985** pinned pages to disk and synching the operating system disk cache. 7986** 7987** [[the xUnpin() page cache method]] 7988** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 7989** as its second argument. If the third parameter, discard, is non-zero, 7990** then the page must be evicted from the cache. 7991** ^If the discard parameter is 7992** zero, then the page may be discarded or retained at the discretion of 7993** page cache implementation. ^The page cache implementation 7994** may choose to evict unpinned pages at any time. 7995** 7996** The cache must not perform any reference counting. A single 7997** call to xUnpin() unpins the page regardless of the number of prior calls 7998** to xFetch(). 7999** 8000** [[the xRekey() page cache methods]] 8001** The xRekey() method is used to change the key value associated with the 8002** page passed as the second argument. If the cache 8003** previously contains an entry associated with newKey, it must be 8004** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8005** to be pinned. 8006** 8007** When SQLite calls the xTruncate() method, the cache must discard all 8008** existing cache entries with page numbers (keys) greater than or equal 8009** to the value of the iLimit parameter passed to xTruncate(). If any 8010** of these pages are pinned, they are implicitly unpinned, meaning that 8011** they can be safely discarded. 8012** 8013** [[the xDestroy() page cache method]] 8014** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8015** All resources associated with the specified cache should be freed. ^After 8016** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8017** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8018** functions. 8019** 8020** [[the xShrink() page cache method]] 8021** ^SQLite invokes the xShrink() method when it wants the page cache to 8022** free up as much of heap memory as possible. The page cache implementation 8023** is not obligated to free any memory, but well-behaved implementations should 8024** do their best. 8025*/ 8026typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8027struct sqlite3_pcache_methods2 { 8028 int iVersion; 8029 void *pArg; 8030 int (*xInit)(void*); 8031 void (*xShutdown)(void*); 8032 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8033 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8034 int (*xPagecount)(sqlite3_pcache*); 8035 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8036 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8037 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8038 unsigned oldKey, unsigned newKey); 8039 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8040 void (*xDestroy)(sqlite3_pcache*); 8041 void (*xShrink)(sqlite3_pcache*); 8042}; 8043 8044/* 8045** This is the obsolete pcache_methods object that has now been replaced 8046** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8047** retained in the header file for backwards compatibility only. 8048*/ 8049typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8050struct sqlite3_pcache_methods { 8051 void *pArg; 8052 int (*xInit)(void*); 8053 void (*xShutdown)(void*); 8054 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8055 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8056 int (*xPagecount)(sqlite3_pcache*); 8057 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8058 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8059 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8060 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8061 void (*xDestroy)(sqlite3_pcache*); 8062}; 8063 8064 8065/* 8066** CAPI3REF: Online Backup Object 8067** 8068** The sqlite3_backup object records state information about an ongoing 8069** online backup operation. ^The sqlite3_backup object is created by 8070** a call to [sqlite3_backup_init()] and is destroyed by a call to 8071** [sqlite3_backup_finish()]. 8072** 8073** See Also: [Using the SQLite Online Backup API] 8074*/ 8075typedef struct sqlite3_backup sqlite3_backup; 8076 8077/* 8078** CAPI3REF: Online Backup API. 8079** 8080** The backup API copies the content of one database into another. 8081** It is useful either for creating backups of databases or 8082** for copying in-memory databases to or from persistent files. 8083** 8084** See Also: [Using the SQLite Online Backup API] 8085** 8086** ^SQLite holds a write transaction open on the destination database file 8087** for the duration of the backup operation. 8088** ^The source database is read-locked only while it is being read; 8089** it is not locked continuously for the entire backup operation. 8090** ^Thus, the backup may be performed on a live source database without 8091** preventing other database connections from 8092** reading or writing to the source database while the backup is underway. 8093** 8094** ^(To perform a backup operation: 8095** <ol> 8096** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8097** backup, 8098** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8099** the data between the two databases, and finally 8100** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8101** associated with the backup operation. 8102** </ol>)^ 8103** There should be exactly one call to sqlite3_backup_finish() for each 8104** successful call to sqlite3_backup_init(). 8105** 8106** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8107** 8108** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8109** [database connection] associated with the destination database 8110** and the database name, respectively. 8111** ^The database name is "main" for the main database, "temp" for the 8112** temporary database, or the name specified after the AS keyword in 8113** an [ATTACH] statement for an attached database. 8114** ^The S and M arguments passed to 8115** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8116** and database name of the source database, respectively. 8117** ^The source and destination [database connections] (parameters S and D) 8118** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8119** an error. 8120** 8121** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8122** there is already a read or read-write transaction open on the 8123** destination database. 8124** 8125** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8126** returned and an error code and error message are stored in the 8127** destination [database connection] D. 8128** ^The error code and message for the failed call to sqlite3_backup_init() 8129** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8130** [sqlite3_errmsg16()] functions. 8131** ^A successful call to sqlite3_backup_init() returns a pointer to an 8132** [sqlite3_backup] object. 8133** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8134** sqlite3_backup_finish() functions to perform the specified backup 8135** operation. 8136** 8137** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8138** 8139** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8140** the source and destination databases specified by [sqlite3_backup] object B. 8141** ^If N is negative, all remaining source pages are copied. 8142** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8143** are still more pages to be copied, then the function returns [SQLITE_OK]. 8144** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8145** from source to destination, then it returns [SQLITE_DONE]. 8146** ^If an error occurs while running sqlite3_backup_step(B,N), 8147** then an [error code] is returned. ^As well as [SQLITE_OK] and 8148** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8149** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8150** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8151** 8152** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8153** <ol> 8154** <li> the destination database was opened read-only, or 8155** <li> the destination database is using write-ahead-log journaling 8156** and the destination and source page sizes differ, or 8157** <li> the destination database is an in-memory database and the 8158** destination and source page sizes differ. 8159** </ol>)^ 8160** 8161** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8162** the [sqlite3_busy_handler | busy-handler function] 8163** is invoked (if one is specified). ^If the 8164** busy-handler returns non-zero before the lock is available, then 8165** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8166** sqlite3_backup_step() can be retried later. ^If the source 8167** [database connection] 8168** is being used to write to the source database when sqlite3_backup_step() 8169** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8170** case the call to sqlite3_backup_step() can be retried later on. ^(If 8171** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8172** [SQLITE_READONLY] is returned, then 8173** there is no point in retrying the call to sqlite3_backup_step(). These 8174** errors are considered fatal.)^ The application must accept 8175** that the backup operation has failed and pass the backup operation handle 8176** to the sqlite3_backup_finish() to release associated resources. 8177** 8178** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8179** on the destination file. ^The exclusive lock is not released until either 8180** sqlite3_backup_finish() is called or the backup operation is complete 8181** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8182** sqlite3_backup_step() obtains a [shared lock] on the source database that 8183** lasts for the duration of the sqlite3_backup_step() call. 8184** ^Because the source database is not locked between calls to 8185** sqlite3_backup_step(), the source database may be modified mid-way 8186** through the backup process. ^If the source database is modified by an 8187** external process or via a database connection other than the one being 8188** used by the backup operation, then the backup will be automatically 8189** restarted by the next call to sqlite3_backup_step(). ^If the source 8190** database is modified by the using the same database connection as is used 8191** by the backup operation, then the backup database is automatically 8192** updated at the same time. 8193** 8194** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8195** 8196** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8197** application wishes to abandon the backup operation, the application 8198** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8199** ^The sqlite3_backup_finish() interfaces releases all 8200** resources associated with the [sqlite3_backup] object. 8201** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8202** active write-transaction on the destination database is rolled back. 8203** The [sqlite3_backup] object is invalid 8204** and may not be used following a call to sqlite3_backup_finish(). 8205** 8206** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8207** sqlite3_backup_step() errors occurred, regardless or whether or not 8208** sqlite3_backup_step() completed. 8209** ^If an out-of-memory condition or IO error occurred during any prior 8210** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8211** sqlite3_backup_finish() returns the corresponding [error code]. 8212** 8213** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8214** is not a permanent error and does not affect the return value of 8215** sqlite3_backup_finish(). 8216** 8217** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8218** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8219** 8220** ^The sqlite3_backup_remaining() routine returns the number of pages still 8221** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8222** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8223** in the source database at the conclusion of the most recent 8224** sqlite3_backup_step(). 8225** ^(The values returned by these functions are only updated by 8226** sqlite3_backup_step(). If the source database is modified in a way that 8227** changes the size of the source database or the number of pages remaining, 8228** those changes are not reflected in the output of sqlite3_backup_pagecount() 8229** and sqlite3_backup_remaining() until after the next 8230** sqlite3_backup_step().)^ 8231** 8232** <b>Concurrent Usage of Database Handles</b> 8233** 8234** ^The source [database connection] may be used by the application for other 8235** purposes while a backup operation is underway or being initialized. 8236** ^If SQLite is compiled and configured to support threadsafe database 8237** connections, then the source database connection may be used concurrently 8238** from within other threads. 8239** 8240** However, the application must guarantee that the destination 8241** [database connection] is not passed to any other API (by any thread) after 8242** sqlite3_backup_init() is called and before the corresponding call to 8243** sqlite3_backup_finish(). SQLite does not currently check to see 8244** if the application incorrectly accesses the destination [database connection] 8245** and so no error code is reported, but the operations may malfunction 8246** nevertheless. Use of the destination database connection while a 8247** backup is in progress might also also cause a mutex deadlock. 8248** 8249** If running in [shared cache mode], the application must 8250** guarantee that the shared cache used by the destination database 8251** is not accessed while the backup is running. In practice this means 8252** that the application must guarantee that the disk file being 8253** backed up to is not accessed by any connection within the process, 8254** not just the specific connection that was passed to sqlite3_backup_init(). 8255** 8256** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8257** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8258** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8259** APIs are not strictly speaking threadsafe. If they are invoked at the 8260** same time as another thread is invoking sqlite3_backup_step() it is 8261** possible that they return invalid values. 8262*/ 8263sqlite3_backup *sqlite3_backup_init( 8264 sqlite3 *pDest, /* Destination database handle */ 8265 const char *zDestName, /* Destination database name */ 8266 sqlite3 *pSource, /* Source database handle */ 8267 const char *zSourceName /* Source database name */ 8268); 8269int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8270int sqlite3_backup_finish(sqlite3_backup *p); 8271int sqlite3_backup_remaining(sqlite3_backup *p); 8272int sqlite3_backup_pagecount(sqlite3_backup *p); 8273 8274/* 8275** CAPI3REF: Unlock Notification 8276** METHOD: sqlite3 8277** 8278** ^When running in shared-cache mode, a database operation may fail with 8279** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8280** individual tables within the shared-cache cannot be obtained. See 8281** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8282** ^This API may be used to register a callback that SQLite will invoke 8283** when the connection currently holding the required lock relinquishes it. 8284** ^This API is only available if the library was compiled with the 8285** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8286** 8287** See Also: [Using the SQLite Unlock Notification Feature]. 8288** 8289** ^Shared-cache locks are released when a database connection concludes 8290** its current transaction, either by committing it or rolling it back. 8291** 8292** ^When a connection (known as the blocked connection) fails to obtain a 8293** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8294** identity of the database connection (the blocking connection) that 8295** has locked the required resource is stored internally. ^After an 8296** application receives an SQLITE_LOCKED error, it may call the 8297** sqlite3_unlock_notify() method with the blocked connection handle as 8298** the first argument to register for a callback that will be invoked 8299** when the blocking connections current transaction is concluded. ^The 8300** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8301** call that concludes the blocking connections transaction. 8302** 8303** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8304** there is a chance that the blocking connection will have already 8305** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8306** If this happens, then the specified callback is invoked immediately, 8307** from within the call to sqlite3_unlock_notify().)^ 8308** 8309** ^If the blocked connection is attempting to obtain a write-lock on a 8310** shared-cache table, and more than one other connection currently holds 8311** a read-lock on the same table, then SQLite arbitrarily selects one of 8312** the other connections to use as the blocking connection. 8313** 8314** ^(There may be at most one unlock-notify callback registered by a 8315** blocked connection. If sqlite3_unlock_notify() is called when the 8316** blocked connection already has a registered unlock-notify callback, 8317** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8318** called with a NULL pointer as its second argument, then any existing 8319** unlock-notify callback is canceled. ^The blocked connections 8320** unlock-notify callback may also be canceled by closing the blocked 8321** connection using [sqlite3_close()]. 8322** 8323** The unlock-notify callback is not reentrant. If an application invokes 8324** any sqlite3_xxx API functions from within an unlock-notify callback, a 8325** crash or deadlock may be the result. 8326** 8327** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8328** returns SQLITE_OK. 8329** 8330** <b>Callback Invocation Details</b> 8331** 8332** When an unlock-notify callback is registered, the application provides a 8333** single void* pointer that is passed to the callback when it is invoked. 8334** However, the signature of the callback function allows SQLite to pass 8335** it an array of void* context pointers. The first argument passed to 8336** an unlock-notify callback is a pointer to an array of void* pointers, 8337** and the second is the number of entries in the array. 8338** 8339** When a blocking connections transaction is concluded, there may be 8340** more than one blocked connection that has registered for an unlock-notify 8341** callback. ^If two or more such blocked connections have specified the 8342** same callback function, then instead of invoking the callback function 8343** multiple times, it is invoked once with the set of void* context pointers 8344** specified by the blocked connections bundled together into an array. 8345** This gives the application an opportunity to prioritize any actions 8346** related to the set of unblocked database connections. 8347** 8348** <b>Deadlock Detection</b> 8349** 8350** Assuming that after registering for an unlock-notify callback a 8351** database waits for the callback to be issued before taking any further 8352** action (a reasonable assumption), then using this API may cause the 8353** application to deadlock. For example, if connection X is waiting for 8354** connection Y's transaction to be concluded, and similarly connection 8355** Y is waiting on connection X's transaction, then neither connection 8356** will proceed and the system may remain deadlocked indefinitely. 8357** 8358** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8359** detection. ^If a given call to sqlite3_unlock_notify() would put the 8360** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8361** unlock-notify callback is registered. The system is said to be in 8362** a deadlocked state if connection A has registered for an unlock-notify 8363** callback on the conclusion of connection B's transaction, and connection 8364** B has itself registered for an unlock-notify callback when connection 8365** A's transaction is concluded. ^Indirect deadlock is also detected, so 8366** the system is also considered to be deadlocked if connection B has 8367** registered for an unlock-notify callback on the conclusion of connection 8368** C's transaction, where connection C is waiting on connection A. ^Any 8369** number of levels of indirection are allowed. 8370** 8371** <b>The "DROP TABLE" Exception</b> 8372** 8373** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8374** always appropriate to call sqlite3_unlock_notify(). There is however, 8375** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8376** SQLite checks if there are any currently executing SELECT statements 8377** that belong to the same connection. If there are, SQLITE_LOCKED is 8378** returned. In this case there is no "blocking connection", so invoking 8379** sqlite3_unlock_notify() results in the unlock-notify callback being 8380** invoked immediately. If the application then re-attempts the "DROP TABLE" 8381** or "DROP INDEX" query, an infinite loop might be the result. 8382** 8383** One way around this problem is to check the extended error code returned 8384** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8385** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8386** the special "DROP TABLE/INDEX" case, the extended error code is just 8387** SQLITE_LOCKED.)^ 8388*/ 8389int sqlite3_unlock_notify( 8390 sqlite3 *pBlocked, /* Waiting connection */ 8391 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8392 void *pNotifyArg /* Argument to pass to xNotify */ 8393); 8394 8395 8396/* 8397** CAPI3REF: String Comparison 8398** 8399** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8400** and extensions to compare the contents of two buffers containing UTF-8 8401** strings in a case-independent fashion, using the same definition of "case 8402** independence" that SQLite uses internally when comparing identifiers. 8403*/ 8404int sqlite3_stricmp(const char *, const char *); 8405int sqlite3_strnicmp(const char *, const char *, int); 8406 8407/* 8408** CAPI3REF: String Globbing 8409* 8410** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8411** string X matches the [GLOB] pattern P. 8412** ^The definition of [GLOB] pattern matching used in 8413** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8414** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8415** is case sensitive. 8416** 8417** Note that this routine returns zero on a match and non-zero if the strings 8418** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8419** 8420** See also: [sqlite3_strlike()]. 8421*/ 8422int sqlite3_strglob(const char *zGlob, const char *zStr); 8423 8424/* 8425** CAPI3REF: String LIKE Matching 8426* 8427** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8428** string X matches the [LIKE] pattern P with escape character E. 8429** ^The definition of [LIKE] pattern matching used in 8430** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8431** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8432** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8433** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8434** insensitive - equivalent upper and lower case ASCII characters match 8435** one another. 8436** 8437** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8438** only ASCII characters are case folded. 8439** 8440** Note that this routine returns zero on a match and non-zero if the strings 8441** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8442** 8443** See also: [sqlite3_strglob()]. 8444*/ 8445int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8446 8447/* 8448** CAPI3REF: Error Logging Interface 8449** 8450** ^The [sqlite3_log()] interface writes a message into the [error log] 8451** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8452** ^If logging is enabled, the zFormat string and subsequent arguments are 8453** used with [sqlite3_snprintf()] to generate the final output string. 8454** 8455** The sqlite3_log() interface is intended for use by extensions such as 8456** virtual tables, collating functions, and SQL functions. While there is 8457** nothing to prevent an application from calling sqlite3_log(), doing so 8458** is considered bad form. 8459** 8460** The zFormat string must not be NULL. 8461** 8462** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8463** will not use dynamically allocated memory. The log message is stored in 8464** a fixed-length buffer on the stack. If the log message is longer than 8465** a few hundred characters, it will be truncated to the length of the 8466** buffer. 8467*/ 8468void sqlite3_log(int iErrCode, const char *zFormat, ...); 8469 8470/* 8471** CAPI3REF: Write-Ahead Log Commit Hook 8472** METHOD: sqlite3 8473** 8474** ^The [sqlite3_wal_hook()] function is used to register a callback that 8475** is invoked each time data is committed to a database in wal mode. 8476** 8477** ^(The callback is invoked by SQLite after the commit has taken place and 8478** the associated write-lock on the database released)^, so the implementation 8479** may read, write or [checkpoint] the database as required. 8480** 8481** ^The first parameter passed to the callback function when it is invoked 8482** is a copy of the third parameter passed to sqlite3_wal_hook() when 8483** registering the callback. ^The second is a copy of the database handle. 8484** ^The third parameter is the name of the database that was written to - 8485** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8486** is the number of pages currently in the write-ahead log file, 8487** including those that were just committed. 8488** 8489** The callback function should normally return [SQLITE_OK]. ^If an error 8490** code is returned, that error will propagate back up through the 8491** SQLite code base to cause the statement that provoked the callback 8492** to report an error, though the commit will have still occurred. If the 8493** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8494** that does not correspond to any valid SQLite error code, the results 8495** are undefined. 8496** 8497** A single database handle may have at most a single write-ahead log callback 8498** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8499** previously registered write-ahead log callback. ^Note that the 8500** [sqlite3_wal_autocheckpoint()] interface and the 8501** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8502** overwrite any prior [sqlite3_wal_hook()] settings. 8503*/ 8504void *sqlite3_wal_hook( 8505 sqlite3*, 8506 int(*)(void *,sqlite3*,const char*,int), 8507 void* 8508); 8509 8510/* 8511** CAPI3REF: Configure an auto-checkpoint 8512** METHOD: sqlite3 8513** 8514** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8515** [sqlite3_wal_hook()] that causes any database on [database connection] D 8516** to automatically [checkpoint] 8517** after committing a transaction if there are N or 8518** more frames in the [write-ahead log] file. ^Passing zero or 8519** a negative value as the nFrame parameter disables automatic 8520** checkpoints entirely. 8521** 8522** ^The callback registered by this function replaces any existing callback 8523** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8524** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8525** configured by this function. 8526** 8527** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8528** from SQL. 8529** 8530** ^Checkpoints initiated by this mechanism are 8531** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8532** 8533** ^Every new [database connection] defaults to having the auto-checkpoint 8534** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8535** pages. The use of this interface 8536** is only necessary if the default setting is found to be suboptimal 8537** for a particular application. 8538*/ 8539int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8540 8541/* 8542** CAPI3REF: Checkpoint a database 8543** METHOD: sqlite3 8544** 8545** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8546** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8547** 8548** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8549** [write-ahead log] for database X on [database connection] D to be 8550** transferred into the database file and for the write-ahead log to 8551** be reset. See the [checkpointing] documentation for addition 8552** information. 8553** 8554** This interface used to be the only way to cause a checkpoint to 8555** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8556** interface was added. This interface is retained for backwards 8557** compatibility and as a convenience for applications that need to manually 8558** start a callback but which do not need the full power (and corresponding 8559** complication) of [sqlite3_wal_checkpoint_v2()]. 8560*/ 8561int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8562 8563/* 8564** CAPI3REF: Checkpoint a database 8565** METHOD: sqlite3 8566** 8567** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8568** operation on database X of [database connection] D in mode M. Status 8569** information is written back into integers pointed to by L and C.)^ 8570** ^(The M parameter must be a valid [checkpoint mode]:)^ 8571** 8572** <dl> 8573** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8574** ^Checkpoint as many frames as possible without waiting for any database 8575** readers or writers to finish, then sync the database file if all frames 8576** in the log were checkpointed. ^The [busy-handler callback] 8577** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8578** ^On the other hand, passive mode might leave the checkpoint unfinished 8579** if there are concurrent readers or writers. 8580** 8581** <dt>SQLITE_CHECKPOINT_FULL<dd> 8582** ^This mode blocks (it invokes the 8583** [sqlite3_busy_handler|busy-handler callback]) until there is no 8584** database writer and all readers are reading from the most recent database 8585** snapshot. ^It then checkpoints all frames in the log file and syncs the 8586** database file. ^This mode blocks new database writers while it is pending, 8587** but new database readers are allowed to continue unimpeded. 8588** 8589** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8590** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8591** that after checkpointing the log file it blocks (calls the 8592** [busy-handler callback]) 8593** until all readers are reading from the database file only. ^This ensures 8594** that the next writer will restart the log file from the beginning. 8595** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8596** database writer attempts while it is pending, but does not impede readers. 8597** 8598** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8599** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8600** addition that it also truncates the log file to zero bytes just prior 8601** to a successful return. 8602** </dl> 8603** 8604** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8605** the log file or to -1 if the checkpoint could not run because 8606** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8607** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8608** log file (including any that were already checkpointed before the function 8609** was called) or to -1 if the checkpoint could not run due to an error or 8610** because the database is not in WAL mode. ^Note that upon successful 8611** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8612** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8613** 8614** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8615** any other process is running a checkpoint operation at the same time, the 8616** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8617** busy-handler configured, it will not be invoked in this case. 8618** 8619** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8620** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8621** obtained immediately, and a busy-handler is configured, it is invoked and 8622** the writer lock retried until either the busy-handler returns 0 or the lock 8623** is successfully obtained. ^The busy-handler is also invoked while waiting for 8624** database readers as described above. ^If the busy-handler returns 0 before 8625** the writer lock is obtained or while waiting for database readers, the 8626** checkpoint operation proceeds from that point in the same way as 8627** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8628** without blocking any further. ^SQLITE_BUSY is returned in this case. 8629** 8630** ^If parameter zDb is NULL or points to a zero length string, then the 8631** specified operation is attempted on all WAL databases [attached] to 8632** [database connection] db. In this case the 8633** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8634** an SQLITE_BUSY error is encountered when processing one or more of the 8635** attached WAL databases, the operation is still attempted on any remaining 8636** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8637** error occurs while processing an attached database, processing is abandoned 8638** and the error code is returned to the caller immediately. ^If no error 8639** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8640** databases, SQLITE_OK is returned. 8641** 8642** ^If database zDb is the name of an attached database that is not in WAL 8643** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8644** zDb is not NULL (or a zero length string) and is not the name of any 8645** attached database, SQLITE_ERROR is returned to the caller. 8646** 8647** ^Unless it returns SQLITE_MISUSE, 8648** the sqlite3_wal_checkpoint_v2() interface 8649** sets the error information that is queried by 8650** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8651** 8652** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8653** from SQL. 8654*/ 8655int sqlite3_wal_checkpoint_v2( 8656 sqlite3 *db, /* Database handle */ 8657 const char *zDb, /* Name of attached database (or NULL) */ 8658 int eMode, /* SQLITE_CHECKPOINT_* value */ 8659 int *pnLog, /* OUT: Size of WAL log in frames */ 8660 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8661); 8662 8663/* 8664** CAPI3REF: Checkpoint Mode Values 8665** KEYWORDS: {checkpoint mode} 8666** 8667** These constants define all valid values for the "checkpoint mode" passed 8668** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8669** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8670** meaning of each of these checkpoint modes. 8671*/ 8672#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8673#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8674#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8675#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8676 8677/* 8678** CAPI3REF: Virtual Table Interface Configuration 8679** 8680** This function may be called by either the [xConnect] or [xCreate] method 8681** of a [virtual table] implementation to configure 8682** various facets of the virtual table interface. 8683** 8684** If this interface is invoked outside the context of an xConnect or 8685** xCreate virtual table method then the behavior is undefined. 8686** 8687** At present, there is only one option that may be configured using 8688** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8689** may be added in the future. 8690*/ 8691int sqlite3_vtab_config(sqlite3*, int op, ...); 8692 8693/* 8694** CAPI3REF: Virtual Table Configuration Options 8695** 8696** These macros define the various options to the 8697** [sqlite3_vtab_config()] interface that [virtual table] implementations 8698** can use to customize and optimize their behavior. 8699** 8700** <dl> 8701** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 8702** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8703** <dd>Calls of the form 8704** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8705** where X is an integer. If X is zero, then the [virtual table] whose 8706** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8707** support constraints. In this configuration (which is the default) if 8708** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8709** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8710** specified as part of the users SQL statement, regardless of the actual 8711** ON CONFLICT mode specified. 8712** 8713** If X is non-zero, then the virtual table implementation guarantees 8714** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8715** any modifications to internal or persistent data structures have been made. 8716** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8717** is able to roll back a statement or database transaction, and abandon 8718** or continue processing the current SQL statement as appropriate. 8719** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8720** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8721** had been ABORT. 8722** 8723** Virtual table implementations that are required to handle OR REPLACE 8724** must do so within the [xUpdate] method. If a call to the 8725** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8726** CONFLICT policy is REPLACE, the virtual table implementation should 8727** silently replace the appropriate rows within the xUpdate callback and 8728** return SQLITE_OK. Or, if this is not possible, it may return 8729** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8730** constraint handling. 8731** </dl> 8732*/ 8733#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8734 8735/* 8736** CAPI3REF: Determine The Virtual Table Conflict Policy 8737** 8738** This function may only be called from within a call to the [xUpdate] method 8739** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8740** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8741** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8742** of the SQL statement that triggered the call to the [xUpdate] method of the 8743** [virtual table]. 8744*/ 8745int sqlite3_vtab_on_conflict(sqlite3 *); 8746 8747/* 8748** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 8749** 8750** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 8751** method of a [virtual table], then it returns true if and only if the 8752** column is being fetched as part of an UPDATE operation during which the 8753** column value will not change. Applications might use this to substitute 8754** a return value that is less expensive to compute and that the corresponding 8755** [xUpdate] method understands as a "no-change" value. 8756** 8757** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 8758** the column is not changed by the UPDATE statement, then the xColumn 8759** method can optionally return without setting a result, without calling 8760** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 8761** In that case, [sqlite3_value_nochange(X)] will return true for the 8762** same column in the [xUpdate] method. 8763*/ 8764int sqlite3_vtab_nochange(sqlite3_context*); 8765 8766/* 8767** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8768** 8769** This function may only be called from within a call to the [xBestIndex] 8770** method of a [virtual table]. 8771** 8772** The first argument must be the sqlite3_index_info object that is the 8773** first parameter to the xBestIndex() method. The second argument must be 8774** an index into the aConstraint[] array belonging to the sqlite3_index_info 8775** structure passed to xBestIndex. This function returns a pointer to a buffer 8776** containing the name of the collation sequence for the corresponding 8777** constraint. 8778*/ 8779SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8780 8781/* 8782** CAPI3REF: Conflict resolution modes 8783** KEYWORDS: {conflict resolution mode} 8784** 8785** These constants are returned by [sqlite3_vtab_on_conflict()] to 8786** inform a [virtual table] implementation what the [ON CONFLICT] mode 8787** is for the SQL statement being evaluated. 8788** 8789** Note that the [SQLITE_IGNORE] constant is also used as a potential 8790** return value from the [sqlite3_set_authorizer()] callback and that 8791** [SQLITE_ABORT] is also a [result code]. 8792*/ 8793#define SQLITE_ROLLBACK 1 8794/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8795#define SQLITE_FAIL 3 8796/* #define SQLITE_ABORT 4 // Also an error code */ 8797#define SQLITE_REPLACE 5 8798 8799/* 8800** CAPI3REF: Prepared Statement Scan Status Opcodes 8801** KEYWORDS: {scanstatus options} 8802** 8803** The following constants can be used for the T parameter to the 8804** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8805** different metric for sqlite3_stmt_scanstatus() to return. 8806** 8807** When the value returned to V is a string, space to hold that string is 8808** managed by the prepared statement S and will be automatically freed when 8809** S is finalized. 8810** 8811** <dl> 8812** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8813** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8814** set to the total number of times that the X-th loop has run.</dd> 8815** 8816** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8817** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8818** to the total number of rows examined by all iterations of the X-th loop.</dd> 8819** 8820** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8821** <dd>^The "double" variable pointed to by the T parameter will be set to the 8822** query planner's estimate for the average number of rows output from each 8823** iteration of the X-th loop. If the query planner's estimates was accurate, 8824** then this value will approximate the quotient NVISIT/NLOOP and the 8825** product of this value for all prior loops with the same SELECTID will 8826** be the NLOOP value for the current loop. 8827** 8828** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8829** <dd>^The "const char *" variable pointed to by the T parameter will be set 8830** to a zero-terminated UTF-8 string containing the name of the index or table 8831** used for the X-th loop. 8832** 8833** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8834** <dd>^The "const char *" variable pointed to by the T parameter will be set 8835** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8836** description for the X-th loop. 8837** 8838** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8839** <dd>^The "int" variable pointed to by the T parameter will be set to the 8840** "select-id" for the X-th loop. The select-id identifies which query or 8841** subquery the loop is part of. The main query has a select-id of zero. 8842** The select-id is the same value as is output in the first column 8843** of an [EXPLAIN QUERY PLAN] query. 8844** </dl> 8845*/ 8846#define SQLITE_SCANSTAT_NLOOP 0 8847#define SQLITE_SCANSTAT_NVISIT 1 8848#define SQLITE_SCANSTAT_EST 2 8849#define SQLITE_SCANSTAT_NAME 3 8850#define SQLITE_SCANSTAT_EXPLAIN 4 8851#define SQLITE_SCANSTAT_SELECTID 5 8852 8853/* 8854** CAPI3REF: Prepared Statement Scan Status 8855** METHOD: sqlite3_stmt 8856** 8857** This interface returns information about the predicted and measured 8858** performance for pStmt. Advanced applications can use this 8859** interface to compare the predicted and the measured performance and 8860** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8861** 8862** Since this interface is expected to be rarely used, it is only 8863** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8864** compile-time option. 8865** 8866** The "iScanStatusOp" parameter determines which status information to return. 8867** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8868** of this interface is undefined. 8869** ^The requested measurement is written into a variable pointed to by 8870** the "pOut" parameter. 8871** Parameter "idx" identifies the specific loop to retrieve statistics for. 8872** Loops are numbered starting from zero. ^If idx is out of range - less than 8873** zero or greater than or equal to the total number of loops used to implement 8874** the statement - a non-zero value is returned and the variable that pOut 8875** points to is unchanged. 8876** 8877** ^Statistics might not be available for all loops in all statements. ^In cases 8878** where there exist loops with no available statistics, this function behaves 8879** as if the loop did not exist - it returns non-zero and leave the variable 8880** that pOut points to unchanged. 8881** 8882** See also: [sqlite3_stmt_scanstatus_reset()] 8883*/ 8884int sqlite3_stmt_scanstatus( 8885 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8886 int idx, /* Index of loop to report on */ 8887 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8888 void *pOut /* Result written here */ 8889); 8890 8891/* 8892** CAPI3REF: Zero Scan-Status Counters 8893** METHOD: sqlite3_stmt 8894** 8895** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8896** 8897** This API is only available if the library is built with pre-processor 8898** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8899*/ 8900void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8901 8902/* 8903** CAPI3REF: Flush caches to disk mid-transaction 8904** 8905** ^If a write-transaction is open on [database connection] D when the 8906** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8907** pages in the pager-cache that are not currently in use are written out 8908** to disk. A dirty page may be in use if a database cursor created by an 8909** active SQL statement is reading from it, or if it is page 1 of a database 8910** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8911** interface flushes caches for all schemas - "main", "temp", and 8912** any [attached] databases. 8913** 8914** ^If this function needs to obtain extra database locks before dirty pages 8915** can be flushed to disk, it does so. ^If those locks cannot be obtained 8916** immediately and there is a busy-handler callback configured, it is invoked 8917** in the usual manner. ^If the required lock still cannot be obtained, then 8918** the database is skipped and an attempt made to flush any dirty pages 8919** belonging to the next (if any) database. ^If any databases are skipped 8920** because locks cannot be obtained, but no other error occurs, this 8921** function returns SQLITE_BUSY. 8922** 8923** ^If any other error occurs while flushing dirty pages to disk (for 8924** example an IO error or out-of-memory condition), then processing is 8925** abandoned and an SQLite [error code] is returned to the caller immediately. 8926** 8927** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8928** 8929** ^This function does not set the database handle error code or message 8930** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8931*/ 8932int sqlite3_db_cacheflush(sqlite3*); 8933 8934/* 8935** CAPI3REF: The pre-update hook. 8936** 8937** ^These interfaces are only available if SQLite is compiled using the 8938** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 8939** 8940** ^The [sqlite3_preupdate_hook()] interface registers a callback function 8941** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 8942** on a database table. 8943** ^At most one preupdate hook may be registered at a time on a single 8944** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 8945** the previous setting. 8946** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 8947** with a NULL pointer as the second parameter. 8948** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 8949** the first parameter to callbacks. 8950** 8951** ^The preupdate hook only fires for changes to real database tables; the 8952** preupdate hook is not invoked for changes to [virtual tables] or to 8953** system tables like sqlite_master or sqlite_stat1. 8954** 8955** ^The second parameter to the preupdate callback is a pointer to 8956** the [database connection] that registered the preupdate hook. 8957** ^The third parameter to the preupdate callback is one of the constants 8958** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 8959** kind of update operation that is about to occur. 8960** ^(The fourth parameter to the preupdate callback is the name of the 8961** database within the database connection that is being modified. This 8962** will be "main" for the main database or "temp" for TEMP tables or 8963** the name given after the AS keyword in the [ATTACH] statement for attached 8964** databases.)^ 8965** ^The fifth parameter to the preupdate callback is the name of the 8966** table that is being modified. 8967** 8968** For an UPDATE or DELETE operation on a [rowid table], the sixth 8969** parameter passed to the preupdate callback is the initial [rowid] of the 8970** row being modified or deleted. For an INSERT operation on a rowid table, 8971** or any operation on a WITHOUT ROWID table, the value of the sixth 8972** parameter is undefined. For an INSERT or UPDATE on a rowid table the 8973** seventh parameter is the final rowid value of the row being inserted 8974** or updated. The value of the seventh parameter passed to the callback 8975** function is not defined for operations on WITHOUT ROWID tables, or for 8976** INSERT operations on rowid tables. 8977** 8978** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 8979** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 8980** provide additional information about a preupdate event. These routines 8981** may only be called from within a preupdate callback. Invoking any of 8982** these routines from outside of a preupdate callback or with a 8983** [database connection] pointer that is different from the one supplied 8984** to the preupdate callback results in undefined and probably undesirable 8985** behavior. 8986** 8987** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 8988** in the row that is being inserted, updated, or deleted. 8989** 8990** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 8991** a [protected sqlite3_value] that contains the value of the Nth column of 8992** the table row before it is updated. The N parameter must be between 0 8993** and one less than the number of columns or the behavior will be 8994** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 8995** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 8996** behavior is undefined. The [sqlite3_value] that P points to 8997** will be destroyed when the preupdate callback returns. 8998** 8999** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9000** a [protected sqlite3_value] that contains the value of the Nth column of 9001** the table row after it is updated. The N parameter must be between 0 9002** and one less than the number of columns or the behavior will be 9003** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9004** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9005** behavior is undefined. The [sqlite3_value] that P points to 9006** will be destroyed when the preupdate callback returns. 9007** 9008** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9009** callback was invoked as a result of a direct insert, update, or delete 9010** operation; or 1 for inserts, updates, or deletes invoked by top-level 9011** triggers; or 2 for changes resulting from triggers called by top-level 9012** triggers; and so forth. 9013** 9014** See also: [sqlite3_update_hook()] 9015*/ 9016#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9017void *sqlite3_preupdate_hook( 9018 sqlite3 *db, 9019 void(*xPreUpdate)( 9020 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9021 sqlite3 *db, /* Database handle */ 9022 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9023 char const *zDb, /* Database name */ 9024 char const *zName, /* Table name */ 9025 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9026 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9027 ), 9028 void* 9029); 9030int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9031int sqlite3_preupdate_count(sqlite3 *); 9032int sqlite3_preupdate_depth(sqlite3 *); 9033int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9034#endif 9035 9036/* 9037** CAPI3REF: Low-level system error code 9038** 9039** ^Attempt to return the underlying operating system error code or error 9040** number that caused the most recent I/O error or failure to open a file. 9041** The return value is OS-dependent. For example, on unix systems, after 9042** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9043** called to get back the underlying "errno" that caused the problem, such 9044** as ENOSPC, EAUTH, EISDIR, and so forth. 9045*/ 9046int sqlite3_system_errno(sqlite3*); 9047 9048/* 9049** CAPI3REF: Database Snapshot 9050** KEYWORDS: {snapshot} {sqlite3_snapshot} 9051** 9052** An instance of the snapshot object records the state of a [WAL mode] 9053** database for some specific point in history. 9054** 9055** In [WAL mode], multiple [database connections] that are open on the 9056** same database file can each be reading a different historical version 9057** of the database file. When a [database connection] begins a read 9058** transaction, that connection sees an unchanging copy of the database 9059** as it existed for the point in time when the transaction first started. 9060** Subsequent changes to the database from other connections are not seen 9061** by the reader until a new read transaction is started. 9062** 9063** The sqlite3_snapshot object records state information about an historical 9064** version of the database file so that it is possible to later open a new read 9065** transaction that sees that historical version of the database rather than 9066** the most recent version. 9067*/ 9068typedef struct sqlite3_snapshot { 9069 unsigned char hidden[48]; 9070} sqlite3_snapshot; 9071 9072/* 9073** CAPI3REF: Record A Database Snapshot 9074** CONSTRUCTOR: sqlite3_snapshot 9075** 9076** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9077** new [sqlite3_snapshot] object that records the current state of 9078** schema S in database connection D. ^On success, the 9079** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9080** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9081** If there is not already a read-transaction open on schema S when 9082** this function is called, one is opened automatically. 9083** 9084** The following must be true for this function to succeed. If any of 9085** the following statements are false when sqlite3_snapshot_get() is 9086** called, SQLITE_ERROR is returned. The final value of *P is undefined 9087** in this case. 9088** 9089** <ul> 9090** <li> The database handle must not be in [autocommit mode]. 9091** 9092** <li> Schema S of [database connection] D must be a [WAL mode] database. 9093** 9094** <li> There must not be a write transaction open on schema S of database 9095** connection D. 9096** 9097** <li> One or more transactions must have been written to the current wal 9098** file since it was created on disk (by any connection). This means 9099** that a snapshot cannot be taken on a wal mode database with no wal 9100** file immediately after it is first opened. At least one transaction 9101** must be written to it first. 9102** </ul> 9103** 9104** This function may also return SQLITE_NOMEM. If it is called with the 9105** database handle in autocommit mode but fails for some other reason, 9106** whether or not a read transaction is opened on schema S is undefined. 9107** 9108** The [sqlite3_snapshot] object returned from a successful call to 9109** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9110** to avoid a memory leak. 9111** 9112** The [sqlite3_snapshot_get()] interface is only available when the 9113** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9114*/ 9115SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9116 sqlite3 *db, 9117 const char *zSchema, 9118 sqlite3_snapshot **ppSnapshot 9119); 9120 9121/* 9122** CAPI3REF: Start a read transaction on an historical snapshot 9123** METHOD: sqlite3_snapshot 9124** 9125** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9126** transaction or upgrades an existing one for schema S of 9127** [database connection] D such that the read transaction refers to 9128** historical [snapshot] P, rather than the most recent change to the 9129** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9130** on success or an appropriate [error code] if it fails. 9131** 9132** ^In order to succeed, the database connection must not be in 9133** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9134** is already a read transaction open on schema S, then the database handle 9135** must have no active statements (SELECT statements that have been passed 9136** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9137** SQLITE_ERROR is returned if either of these conditions is violated, or 9138** if schema S does not exist, or if the snapshot object is invalid. 9139** 9140** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9141** snapshot has been overwritten by a [checkpoint]. In this case 9142** SQLITE_ERROR_SNAPSHOT is returned. 9143** 9144** If there is already a read transaction open when this function is 9145** invoked, then the same read transaction remains open (on the same 9146** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9147** is returned. If another error code - for example SQLITE_PROTOCOL or an 9148** SQLITE_IOERR error code - is returned, then the final state of the 9149** read transaction is undefined. If SQLITE_OK is returned, then the 9150** read transaction is now open on database snapshot P. 9151** 9152** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9153** database connection D does not know that the database file for 9154** schema S is in [WAL mode]. A database connection might not know 9155** that the database file is in [WAL mode] if there has been no prior 9156** I/O on that database connection, or if the database entered [WAL mode] 9157** after the most recent I/O on the database connection.)^ 9158** (Hint: Run "[PRAGMA application_id]" against a newly opened 9159** database connection in order to make it ready to use snapshots.) 9160** 9161** The [sqlite3_snapshot_open()] interface is only available when the 9162** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9163*/ 9164SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9165 sqlite3 *db, 9166 const char *zSchema, 9167 sqlite3_snapshot *pSnapshot 9168); 9169 9170/* 9171** CAPI3REF: Destroy a snapshot 9172** DESTRUCTOR: sqlite3_snapshot 9173** 9174** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9175** The application must eventually free every [sqlite3_snapshot] object 9176** using this routine to avoid a memory leak. 9177** 9178** The [sqlite3_snapshot_free()] interface is only available when the 9179** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9180*/ 9181SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9182 9183/* 9184** CAPI3REF: Compare the ages of two snapshot handles. 9185** METHOD: sqlite3_snapshot 9186** 9187** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9188** of two valid snapshot handles. 9189** 9190** If the two snapshot handles are not associated with the same database 9191** file, the result of the comparison is undefined. 9192** 9193** Additionally, the result of the comparison is only valid if both of the 9194** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9195** last time the wal file was deleted. The wal file is deleted when the 9196** database is changed back to rollback mode or when the number of database 9197** clients drops to zero. If either snapshot handle was obtained before the 9198** wal file was last deleted, the value returned by this function 9199** is undefined. 9200** 9201** Otherwise, this API returns a negative value if P1 refers to an older 9202** snapshot than P2, zero if the two handles refer to the same database 9203** snapshot, and a positive value if P1 is a newer snapshot than P2. 9204** 9205** This interface is only available if SQLite is compiled with the 9206** [SQLITE_ENABLE_SNAPSHOT] option. 9207*/ 9208SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9209 sqlite3_snapshot *p1, 9210 sqlite3_snapshot *p2 9211); 9212 9213/* 9214** CAPI3REF: Recover snapshots from a wal file 9215** METHOD: sqlite3_snapshot 9216** 9217** If a [WAL file] remains on disk after all database connections close 9218** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9219** or because the last process to have the database opened exited without 9220** calling [sqlite3_close()]) and a new connection is subsequently opened 9221** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9222** will only be able to open the last transaction added to the WAL file 9223** even though the WAL file contains other valid transactions. 9224** 9225** This function attempts to scan the WAL file associated with database zDb 9226** of database handle db and make all valid snapshots available to 9227** sqlite3_snapshot_open(). It is an error if there is already a read 9228** transaction open on the database, or if the database is not a WAL mode 9229** database. 9230** 9231** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9232** 9233** This interface is only available if SQLite is compiled with the 9234** [SQLITE_ENABLE_SNAPSHOT] option. 9235*/ 9236SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9237 9238/* 9239** CAPI3REF: Serialize a database 9240** 9241** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9242** that is a serialization of the S database on [database connection] D. 9243** If P is not a NULL pointer, then the size of the database in bytes 9244** is written into *P. 9245** 9246** For an ordinary on-disk database file, the serialization is just a 9247** copy of the disk file. For an in-memory database or a "TEMP" database, 9248** the serialization is the same sequence of bytes which would be written 9249** to disk if that database where backed up to disk. 9250** 9251** The usual case is that sqlite3_serialize() copies the serialization of 9252** the database into memory obtained from [sqlite3_malloc64()] and returns 9253** a pointer to that memory. The caller is responsible for freeing the 9254** returned value to avoid a memory leak. However, if the F argument 9255** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9256** are made, and the sqlite3_serialize() function will return a pointer 9257** to the contiguous memory representation of the database that SQLite 9258** is currently using for that database, or NULL if the no such contiguous 9259** memory representation of the database exists. A contiguous memory 9260** representation of the database will usually only exist if there has 9261** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9262** values of D and S. 9263** The size of the database is written into *P even if the 9264** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9265** of the database exists. 9266** 9267** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9268** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9269** allocation error occurs. 9270** 9271** This interface is only available if SQLite is compiled with the 9272** [SQLITE_ENABLE_DESERIALIZE] option. 9273*/ 9274unsigned char *sqlite3_serialize( 9275 sqlite3 *db, /* The database connection */ 9276 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9277 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9278 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9279); 9280 9281/* 9282** CAPI3REF: Flags for sqlite3_serialize 9283** 9284** Zero or more of the following constants can be OR-ed together for 9285** the F argument to [sqlite3_serialize(D,S,P,F)]. 9286** 9287** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9288** a pointer to contiguous in-memory database that it is currently using, 9289** without making a copy of the database. If SQLite is not currently using 9290** a contiguous in-memory database, then this option causes 9291** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9292** using a contiguous in-memory database if it has been initialized by a 9293** prior call to [sqlite3_deserialize()]. 9294*/ 9295#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9296 9297/* 9298** CAPI3REF: Deserialize a database 9299** 9300** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9301** [database connection] D to disconnect from database S and then 9302** reopen S as an in-memory database based on the serialization contained 9303** in P. The serialized database P is N bytes in size. M is the size of 9304** the buffer P, which might be larger than N. If M is larger than N, and 9305** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9306** permitted to add content to the in-memory database as long as the total 9307** size does not exceed M bytes. 9308** 9309** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9310** invoke sqlite3_free() on the serialization buffer when the database 9311** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9312** SQLite will try to increase the buffer size using sqlite3_realloc64() 9313** if writes on the database cause it to grow larger than M bytes. 9314** 9315** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9316** database is currently in a read transaction or is involved in a backup 9317** operation. 9318** 9319** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9320** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9321** [sqlite3_free()] is invoked on argument P prior to returning. 9322** 9323** This interface is only available if SQLite is compiled with the 9324** [SQLITE_ENABLE_DESERIALIZE] option. 9325*/ 9326int sqlite3_deserialize( 9327 sqlite3 *db, /* The database connection */ 9328 const char *zSchema, /* Which DB to reopen with the deserialization */ 9329 unsigned char *pData, /* The serialized database content */ 9330 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9331 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9332 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9333); 9334 9335/* 9336** CAPI3REF: Flags for sqlite3_deserialize() 9337** 9338** The following are allowed values for 6th argument (the F argument) to 9339** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9340** 9341** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9342** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9343** and that SQLite should take ownership of this memory and automatically 9344** free it when it has finished using it. Without this flag, the caller 9345** is responsible for freeing any dynamically allocated memory. 9346** 9347** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9348** grow the size of the database using calls to [sqlite3_realloc64()]. This 9349** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9350** Without this flag, the deserialized database cannot increase in size beyond 9351** the number of bytes specified by the M parameter. 9352** 9353** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9354** should be treated as read-only. 9355*/ 9356#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9357#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9358#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9359 9360/* 9361** Undo the hack that converts floating point types to integer for 9362** builds on processors without floating point support. 9363*/ 9364#ifdef SQLITE_OMIT_FLOATING_POINT 9365# undef double 9366#endif 9367 9368#ifdef __cplusplus 9369} /* End of the 'extern "C"' block */ 9370#endif 9371#endif /* SQLITE3_H */ 9372