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#else 193# define sqlite3_compileoption_used(X) 0 194# define sqlite3_compileoption_get(X) ((void*)0) 195#endif 196 197/* 198** CAPI3REF: Test To See If The Library Is Threadsafe 199** 200** ^The sqlite3_threadsafe() function returns zero if and only if 201** SQLite was compiled with mutexing code omitted due to the 202** [SQLITE_THREADSAFE] compile-time option being set to 0. 203** 204** SQLite can be compiled with or without mutexes. When 205** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 206** are enabled and SQLite is threadsafe. When the 207** [SQLITE_THREADSAFE] macro is 0, 208** the mutexes are omitted. Without the mutexes, it is not safe 209** to use SQLite concurrently from more than one thread. 210** 211** Enabling mutexes incurs a measurable performance penalty. 212** So if speed is of utmost importance, it makes sense to disable 213** the mutexes. But for maximum safety, mutexes should be enabled. 214** ^The default behavior is for mutexes to be enabled. 215** 216** This interface can be used by an application to make sure that the 217** version of SQLite that it is linking against was compiled with 218** the desired setting of the [SQLITE_THREADSAFE] macro. 219** 220** This interface only reports on the compile-time mutex setting 221** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 222** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 223** can be fully or partially disabled using a call to [sqlite3_config()] 224** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 225** or [SQLITE_CONFIG_SERIALIZED]. ^(The return value of the 226** sqlite3_threadsafe() function shows only the compile-time setting of 227** thread safety, not any run-time changes to that setting made by 228** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 229** is unchanged by calls to sqlite3_config().)^ 230** 231** See the [threading mode] documentation for additional information. 232*/ 233int sqlite3_threadsafe(void); 234 235/* 236** CAPI3REF: Database Connection Handle 237** KEYWORDS: {database connection} {database connections} 238** 239** Each open SQLite database is represented by a pointer to an instance of 240** the opaque structure named "sqlite3". It is useful to think of an sqlite3 241** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 242** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 243** and [sqlite3_close_v2()] are its destructors. There are many other 244** interfaces (such as 245** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 246** [sqlite3_busy_timeout()] to name but three) that are methods on an 247** sqlite3 object. 248*/ 249typedef struct sqlite3 sqlite3; 250 251/* 252** CAPI3REF: 64-Bit Integer Types 253** KEYWORDS: sqlite_int64 sqlite_uint64 254** 255** Because there is no cross-platform way to specify 64-bit integer types 256** SQLite includes typedefs for 64-bit signed and unsigned integers. 257** 258** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 259** The sqlite_int64 and sqlite_uint64 types are supported for backwards 260** compatibility only. 261** 262** ^The sqlite3_int64 and sqlite_int64 types can store integer values 263** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 264** sqlite3_uint64 and sqlite_uint64 types can store integer values 265** between 0 and +18446744073709551615 inclusive. 266*/ 267#ifdef SQLITE_INT64_TYPE 268 typedef SQLITE_INT64_TYPE sqlite_int64; 269# ifdef SQLITE_UINT64_TYPE 270 typedef SQLITE_UINT64_TYPE sqlite_uint64; 271# else 272 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 273# endif 274#elif defined(_MSC_VER) || defined(__BORLANDC__) 275 typedef __int64 sqlite_int64; 276 typedef unsigned __int64 sqlite_uint64; 277#else 278 typedef long long int sqlite_int64; 279 typedef unsigned long long int sqlite_uint64; 280#endif 281typedef sqlite_int64 sqlite3_int64; 282typedef sqlite_uint64 sqlite3_uint64; 283 284/* 285** If compiling for a processor that lacks floating point support, 286** substitute integer for floating-point. 287*/ 288#ifdef SQLITE_OMIT_FLOATING_POINT 289# define double sqlite3_int64 290#endif 291 292/* 293** CAPI3REF: Closing A Database Connection 294** DESTRUCTOR: sqlite3 295** 296** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors 297** for the [sqlite3] object. 298** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if 299** the [sqlite3] object is successfully destroyed and all associated 300** resources are deallocated. 301** 302** ^If the database connection is associated with unfinalized prepared 303** statements or unfinished sqlite3_backup objects then sqlite3_close() 304** will leave the database connection open and return [SQLITE_BUSY]. 305** ^If sqlite3_close_v2() is called with unfinalized prepared statements 306** and/or unfinished sqlite3_backups, then the database connection becomes 307** an unusable "zombie" which will automatically be deallocated when the 308** last prepared statement is finalized or the last sqlite3_backup is 309** finished. The sqlite3_close_v2() interface is intended for use with 310** host languages that are garbage collected, and where the order in which 311** destructors are called is arbitrary. 312** 313** Applications should [sqlite3_finalize | finalize] all [prepared statements], 314** [sqlite3_blob_close | close] all [BLOB handles], and 315** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated 316** with the [sqlite3] object prior to attempting to close the object. ^If 317** sqlite3_close_v2() is called on a [database connection] that still has 318** outstanding [prepared statements], [BLOB handles], and/or 319** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation 320** of resources is deferred until all [prepared statements], [BLOB handles], 321** and [sqlite3_backup] objects are also destroyed. 322** 323** ^If an [sqlite3] object is destroyed while a transaction is open, 324** the transaction is automatically rolled back. 325** 326** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)] 327** must be either a NULL 328** pointer or an [sqlite3] object pointer obtained 329** from [sqlite3_open()], [sqlite3_open16()], or 330** [sqlite3_open_v2()], and not previously closed. 331** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer 332** argument is a harmless no-op. 333*/ 334int sqlite3_close(sqlite3*); 335int sqlite3_close_v2(sqlite3*); 336 337/* 338** The type for a callback function. 339** This is legacy and deprecated. It is included for historical 340** compatibility and is not documented. 341*/ 342typedef int (*sqlite3_callback)(void*,int,char**, char**); 343 344/* 345** CAPI3REF: One-Step Query Execution Interface 346** METHOD: sqlite3 347** 348** The sqlite3_exec() interface is a convenience wrapper around 349** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 350** that allows an application to run multiple statements of SQL 351** without having to use a lot of C code. 352** 353** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 354** semicolon-separate SQL statements passed into its 2nd argument, 355** in the context of the [database connection] passed in as its 1st 356** argument. ^If the callback function of the 3rd argument to 357** sqlite3_exec() is not NULL, then it is invoked for each result row 358** coming out of the evaluated SQL statements. ^The 4th argument to 359** sqlite3_exec() is relayed through to the 1st argument of each 360** callback invocation. ^If the callback pointer to sqlite3_exec() 361** is NULL, then no callback is ever invoked and result rows are 362** ignored. 363** 364** ^If an error occurs while evaluating the SQL statements passed into 365** sqlite3_exec(), then execution of the current statement stops and 366** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 367** is not NULL then any error message is written into memory obtained 368** from [sqlite3_malloc()] and passed back through the 5th parameter. 369** To avoid memory leaks, the application should invoke [sqlite3_free()] 370** on error message strings returned through the 5th parameter of 371** sqlite3_exec() after the error message string is no longer needed. 372** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 373** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 374** NULL before returning. 375** 376** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 377** routine returns SQLITE_ABORT without invoking the callback again and 378** without running any subsequent SQL statements. 379** 380** ^The 2nd argument to the sqlite3_exec() callback function is the 381** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 382** callback is an array of pointers to strings obtained as if from 383** [sqlite3_column_text()], one for each column. ^If an element of a 384** result row is NULL then the corresponding string pointer for the 385** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 386** sqlite3_exec() callback is an array of pointers to strings where each 387** entry represents the name of corresponding result column as obtained 388** from [sqlite3_column_name()]. 389** 390** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 391** to an empty string, or a pointer that contains only whitespace and/or 392** SQL comments, then no SQL statements are evaluated and the database 393** is not changed. 394** 395** Restrictions: 396** 397** <ul> 398** <li> The application must ensure that the 1st parameter to sqlite3_exec() 399** is a valid and open [database connection]. 400** <li> The application must not close the [database connection] specified by 401** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 402** <li> The application must not modify the SQL statement text passed into 403** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 404** </ul> 405*/ 406int sqlite3_exec( 407 sqlite3*, /* An open database */ 408 const char *sql, /* SQL to be evaluated */ 409 int (*callback)(void*,int,char**,char**), /* Callback function */ 410 void *, /* 1st argument to callback */ 411 char **errmsg /* Error msg written here */ 412); 413 414/* 415** CAPI3REF: Result Codes 416** KEYWORDS: {result code definitions} 417** 418** Many SQLite functions return an integer result code from the set shown 419** here in order to indicate success or failure. 420** 421** New error codes may be added in future versions of SQLite. 422** 423** See also: [extended result code definitions] 424*/ 425#define SQLITE_OK 0 /* Successful result */ 426/* beginning-of-error-codes */ 427#define SQLITE_ERROR 1 /* Generic error */ 428#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 429#define SQLITE_PERM 3 /* Access permission denied */ 430#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 431#define SQLITE_BUSY 5 /* The database file is locked */ 432#define SQLITE_LOCKED 6 /* A table in the database is locked */ 433#define SQLITE_NOMEM 7 /* A malloc() failed */ 434#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 435#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 436#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 437#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 438#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 439#define SQLITE_FULL 13 /* Insertion failed because database is full */ 440#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 441#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 442#define SQLITE_EMPTY 16 /* Internal use only */ 443#define SQLITE_SCHEMA 17 /* The database schema changed */ 444#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 445#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 446#define SQLITE_MISMATCH 20 /* Data type mismatch */ 447#define SQLITE_MISUSE 21 /* Library used incorrectly */ 448#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 449#define SQLITE_AUTH 23 /* Authorization denied */ 450#define SQLITE_FORMAT 24 /* Not used */ 451#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 452#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 453#define SQLITE_NOTICE 27 /* Notifications from sqlite3_log() */ 454#define SQLITE_WARNING 28 /* Warnings from sqlite3_log() */ 455#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 456#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 457/* end-of-error-codes */ 458 459/* 460** CAPI3REF: Extended Result Codes 461** KEYWORDS: {extended result code definitions} 462** 463** In its default configuration, SQLite API routines return one of 30 integer 464** [result codes]. However, experience has shown that many of 465** these result codes are too coarse-grained. They do not provide as 466** much information about problems as programmers might like. In an effort to 467** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8] 468** and later) include 469** support for additional result codes that provide more detailed information 470** about errors. These [extended result codes] are enabled or disabled 471** on a per database connection basis using the 472** [sqlite3_extended_result_codes()] API. Or, the extended code for 473** the most recent error can be obtained using 474** [sqlite3_extended_errcode()]. 475*/ 476#define SQLITE_ERROR_MISSING_COLLSEQ (SQLITE_ERROR | (1<<8)) 477#define SQLITE_ERROR_RETRY (SQLITE_ERROR | (2<<8)) 478#define SQLITE_ERROR_SNAPSHOT (SQLITE_ERROR | (3<<8)) 479#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 480#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 481#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 482#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 483#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 484#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 485#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 486#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 487#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 488#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 489#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 490#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 491#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 492#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 493#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 494#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 495#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 496#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 497#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 498#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 499#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 500#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 501#define SQLITE_IOERR_DELETE_NOENT (SQLITE_IOERR | (23<<8)) 502#define SQLITE_IOERR_MMAP (SQLITE_IOERR | (24<<8)) 503#define SQLITE_IOERR_GETTEMPPATH (SQLITE_IOERR | (25<<8)) 504#define SQLITE_IOERR_CONVPATH (SQLITE_IOERR | (26<<8)) 505#define SQLITE_IOERR_VNODE (SQLITE_IOERR | (27<<8)) 506#define SQLITE_IOERR_AUTH (SQLITE_IOERR | (28<<8)) 507#define SQLITE_IOERR_BEGIN_ATOMIC (SQLITE_IOERR | (29<<8)) 508#define SQLITE_IOERR_COMMIT_ATOMIC (SQLITE_IOERR | (30<<8)) 509#define SQLITE_IOERR_ROLLBACK_ATOMIC (SQLITE_IOERR | (31<<8)) 510#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 511#define SQLITE_LOCKED_VTAB (SQLITE_LOCKED | (2<<8)) 512#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 513#define SQLITE_BUSY_SNAPSHOT (SQLITE_BUSY | (2<<8)) 514#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 515#define SQLITE_CANTOPEN_ISDIR (SQLITE_CANTOPEN | (2<<8)) 516#define SQLITE_CANTOPEN_FULLPATH (SQLITE_CANTOPEN | (3<<8)) 517#define SQLITE_CANTOPEN_CONVPATH (SQLITE_CANTOPEN | (4<<8)) 518#define SQLITE_CANTOPEN_DIRTYWAL (SQLITE_CANTOPEN | (5<<8)) /* Not Used */ 519#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 520#define SQLITE_CORRUPT_SEQUENCE (SQLITE_CORRUPT | (2<<8)) 521#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 522#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 523#define SQLITE_READONLY_ROLLBACK (SQLITE_READONLY | (3<<8)) 524#define SQLITE_READONLY_DBMOVED (SQLITE_READONLY | (4<<8)) 525#define SQLITE_READONLY_CANTINIT (SQLITE_READONLY | (5<<8)) 526#define SQLITE_READONLY_DIRECTORY (SQLITE_READONLY | (6<<8)) 527#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 528#define SQLITE_CONSTRAINT_CHECK (SQLITE_CONSTRAINT | (1<<8)) 529#define SQLITE_CONSTRAINT_COMMITHOOK (SQLITE_CONSTRAINT | (2<<8)) 530#define SQLITE_CONSTRAINT_FOREIGNKEY (SQLITE_CONSTRAINT | (3<<8)) 531#define SQLITE_CONSTRAINT_FUNCTION (SQLITE_CONSTRAINT | (4<<8)) 532#define SQLITE_CONSTRAINT_NOTNULL (SQLITE_CONSTRAINT | (5<<8)) 533#define SQLITE_CONSTRAINT_PRIMARYKEY (SQLITE_CONSTRAINT | (6<<8)) 534#define SQLITE_CONSTRAINT_TRIGGER (SQLITE_CONSTRAINT | (7<<8)) 535#define SQLITE_CONSTRAINT_UNIQUE (SQLITE_CONSTRAINT | (8<<8)) 536#define SQLITE_CONSTRAINT_VTAB (SQLITE_CONSTRAINT | (9<<8)) 537#define SQLITE_CONSTRAINT_ROWID (SQLITE_CONSTRAINT |(10<<8)) 538#define SQLITE_NOTICE_RECOVER_WAL (SQLITE_NOTICE | (1<<8)) 539#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8)) 540#define SQLITE_WARNING_AUTOINDEX (SQLITE_WARNING | (1<<8)) 541#define SQLITE_AUTH_USER (SQLITE_AUTH | (1<<8)) 542#define SQLITE_OK_LOAD_PERMANENTLY (SQLITE_OK | (1<<8)) 543 544/* 545** CAPI3REF: Flags For File Open Operations 546** 547** These bit values are intended for use in the 548** 3rd parameter to the [sqlite3_open_v2()] interface and 549** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 550*/ 551#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 552#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 553#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 554#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 555#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 556#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 557#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 558#define SQLITE_OPEN_MEMORY 0x00000080 /* Ok for sqlite3_open_v2() */ 559#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 560#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 561#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 562#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 563#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 564#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 565#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 566#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 567#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 568#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 569#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 570#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 571 572/* Reserved: 0x00F00000 */ 573 574/* 575** CAPI3REF: Device Characteristics 576** 577** The xDeviceCharacteristics method of the [sqlite3_io_methods] 578** object returns an integer which is a vector of these 579** bit values expressing I/O characteristics of the mass storage 580** device that holds the file that the [sqlite3_io_methods] 581** refers to. 582** 583** The SQLITE_IOCAP_ATOMIC property means that all writes of 584** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 585** mean that writes of blocks that are nnn bytes in size and 586** are aligned to an address which is an integer multiple of 587** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 588** that when data is appended to a file, the data is appended 589** first then the size of the file is extended, never the other 590** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 591** information is written to disk in the same order as calls 592** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 593** after reboot following a crash or power loss, the only bytes in a 594** file that were written at the application level might have changed 595** and that adjacent bytes, even bytes within the same sector are 596** guaranteed to be unchanged. The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 597** flag indicates that a file cannot be deleted when open. The 598** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on 599** read-only media and cannot be changed even by processes with 600** elevated privileges. 601** 602** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying 603** filesystem supports doing multiple write operations atomically when those 604** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and 605** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. 606*/ 607#define SQLITE_IOCAP_ATOMIC 0x00000001 608#define SQLITE_IOCAP_ATOMIC512 0x00000002 609#define SQLITE_IOCAP_ATOMIC1K 0x00000004 610#define SQLITE_IOCAP_ATOMIC2K 0x00000008 611#define SQLITE_IOCAP_ATOMIC4K 0x00000010 612#define SQLITE_IOCAP_ATOMIC8K 0x00000020 613#define SQLITE_IOCAP_ATOMIC16K 0x00000040 614#define SQLITE_IOCAP_ATOMIC32K 0x00000080 615#define SQLITE_IOCAP_ATOMIC64K 0x00000100 616#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 617#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 618#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 619#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 620#define SQLITE_IOCAP_IMMUTABLE 0x00002000 621#define SQLITE_IOCAP_BATCH_ATOMIC 0x00004000 622 623/* 624** CAPI3REF: File Locking Levels 625** 626** SQLite uses one of these integer values as the second 627** argument to calls it makes to the xLock() and xUnlock() methods 628** of an [sqlite3_io_methods] object. 629*/ 630#define SQLITE_LOCK_NONE 0 631#define SQLITE_LOCK_SHARED 1 632#define SQLITE_LOCK_RESERVED 2 633#define SQLITE_LOCK_PENDING 3 634#define SQLITE_LOCK_EXCLUSIVE 4 635 636/* 637** CAPI3REF: Synchronization Type Flags 638** 639** When SQLite invokes the xSync() method of an 640** [sqlite3_io_methods] object it uses a combination of 641** these integer values as the second argument. 642** 643** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 644** sync operation only needs to flush data to mass storage. Inode 645** information need not be flushed. If the lower four bits of the flag 646** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 647** If the lower four bits equal SQLITE_SYNC_FULL, that means 648** to use Mac OS X style fullsync instead of fsync(). 649** 650** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 651** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 652** settings. The [synchronous pragma] determines when calls to the 653** xSync VFS method occur and applies uniformly across all platforms. 654** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 655** energetic or rigorous or forceful the sync operations are and 656** only make a difference on Mac OSX for the default SQLite code. 657** (Third-party VFS implementations might also make the distinction 658** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 659** operating systems natively supported by SQLite, only Mac OSX 660** cares about the difference.) 661*/ 662#define SQLITE_SYNC_NORMAL 0x00002 663#define SQLITE_SYNC_FULL 0x00003 664#define SQLITE_SYNC_DATAONLY 0x00010 665 666/* 667** CAPI3REF: OS Interface Open File Handle 668** 669** An [sqlite3_file] object represents an open file in the 670** [sqlite3_vfs | OS interface layer]. Individual OS interface 671** implementations will 672** want to subclass this object by appending additional fields 673** for their own use. The pMethods entry is a pointer to an 674** [sqlite3_io_methods] object that defines methods for performing 675** I/O operations on the open file. 676*/ 677typedef struct sqlite3_file sqlite3_file; 678struct sqlite3_file { 679 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 680}; 681 682/* 683** CAPI3REF: OS Interface File Virtual Methods Object 684** 685** Every file opened by the [sqlite3_vfs.xOpen] method populates an 686** [sqlite3_file] object (or, more commonly, a subclass of the 687** [sqlite3_file] object) with a pointer to an instance of this object. 688** This object defines the methods used to perform various operations 689** against the open file represented by the [sqlite3_file] object. 690** 691** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 692** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 693** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 694** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 695** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 696** to NULL. 697** 698** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 699** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 700** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 701** flag may be ORed in to indicate that only the data of the file 702** and not its inode needs to be synced. 703** 704** The integer values to xLock() and xUnlock() are one of 705** <ul> 706** <li> [SQLITE_LOCK_NONE], 707** <li> [SQLITE_LOCK_SHARED], 708** <li> [SQLITE_LOCK_RESERVED], 709** <li> [SQLITE_LOCK_PENDING], or 710** <li> [SQLITE_LOCK_EXCLUSIVE]. 711** </ul> 712** xLock() increases the lock. xUnlock() decreases the lock. 713** The xCheckReservedLock() method checks whether any database connection, 714** either in this process or in some other process, is holding a RESERVED, 715** PENDING, or EXCLUSIVE lock on the file. It returns true 716** if such a lock exists and false otherwise. 717** 718** The xFileControl() method is a generic interface that allows custom 719** VFS implementations to directly control an open file using the 720** [sqlite3_file_control()] interface. The second "op" argument is an 721** integer opcode. The third argument is a generic pointer intended to 722** point to a structure that may contain arguments or space in which to 723** write return values. Potential uses for xFileControl() might be 724** functions to enable blocking locks with timeouts, to change the 725** locking strategy (for example to use dot-file locks), to inquire 726** about the status of a lock, or to break stale locks. The SQLite 727** core reserves all opcodes less than 100 for its own use. 728** A [file control opcodes | list of opcodes] less than 100 is available. 729** Applications that define a custom xFileControl method should use opcodes 730** greater than 100 to avoid conflicts. VFS implementations should 731** return [SQLITE_NOTFOUND] for file control opcodes that they do not 732** recognize. 733** 734** The xSectorSize() method returns the sector size of the 735** device that underlies the file. The sector size is the 736** minimum write that can be performed without disturbing 737** other bytes in the file. The xDeviceCharacteristics() 738** method returns a bit vector describing behaviors of the 739** underlying device: 740** 741** <ul> 742** <li> [SQLITE_IOCAP_ATOMIC] 743** <li> [SQLITE_IOCAP_ATOMIC512] 744** <li> [SQLITE_IOCAP_ATOMIC1K] 745** <li> [SQLITE_IOCAP_ATOMIC2K] 746** <li> [SQLITE_IOCAP_ATOMIC4K] 747** <li> [SQLITE_IOCAP_ATOMIC8K] 748** <li> [SQLITE_IOCAP_ATOMIC16K] 749** <li> [SQLITE_IOCAP_ATOMIC32K] 750** <li> [SQLITE_IOCAP_ATOMIC64K] 751** <li> [SQLITE_IOCAP_SAFE_APPEND] 752** <li> [SQLITE_IOCAP_SEQUENTIAL] 753** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN] 754** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE] 755** <li> [SQLITE_IOCAP_IMMUTABLE] 756** <li> [SQLITE_IOCAP_BATCH_ATOMIC] 757** </ul> 758** 759** The SQLITE_IOCAP_ATOMIC property means that all writes of 760** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 761** mean that writes of blocks that are nnn bytes in size and 762** are aligned to an address which is an integer multiple of 763** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 764** that when data is appended to a file, the data is appended 765** first then the size of the file is extended, never the other 766** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 767** information is written to disk in the same order as calls 768** to xWrite(). 769** 770** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 771** in the unread portions of the buffer with zeros. A VFS that 772** fails to zero-fill short reads might seem to work. However, 773** failure to zero-fill short reads will eventually lead to 774** database corruption. 775*/ 776typedef struct sqlite3_io_methods sqlite3_io_methods; 777struct sqlite3_io_methods { 778 int iVersion; 779 int (*xClose)(sqlite3_file*); 780 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 781 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 782 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 783 int (*xSync)(sqlite3_file*, int flags); 784 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 785 int (*xLock)(sqlite3_file*, int); 786 int (*xUnlock)(sqlite3_file*, int); 787 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 788 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 789 int (*xSectorSize)(sqlite3_file*); 790 int (*xDeviceCharacteristics)(sqlite3_file*); 791 /* Methods above are valid for version 1 */ 792 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 793 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 794 void (*xShmBarrier)(sqlite3_file*); 795 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 796 /* Methods above are valid for version 2 */ 797 int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); 798 int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p); 799 /* Methods above are valid for version 3 */ 800 /* Additional methods may be added in future releases */ 801}; 802 803/* 804** CAPI3REF: Standard File Control Opcodes 805** KEYWORDS: {file control opcodes} {file control opcode} 806** 807** These integer constants are opcodes for the xFileControl method 808** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 809** interface. 810** 811** <ul> 812** <li>[[SQLITE_FCNTL_LOCKSTATE]] 813** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 814** opcode causes the xFileControl method to write the current state of 815** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 816** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 817** into an integer that the pArg argument points to. This capability 818** is used during testing and is only available when the SQLITE_TEST 819** compile-time option is used. 820** 821** <li>[[SQLITE_FCNTL_SIZE_HINT]] 822** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 823** layer a hint of how large the database file will grow to be during the 824** current transaction. This hint is not guaranteed to be accurate but it 825** is often close. The underlying VFS might choose to preallocate database 826** file space based on this hint in order to help writes to the database 827** file run faster. 828** 829** <li>[[SQLITE_FCNTL_SIZE_LIMIT]] 830** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that 831** implements [sqlite3_deserialize()] to set an upper bound on the size 832** of the in-memory database. The argument is a pointer to a [sqlite3_int64]. 833** If the integer pointed to is negative, then it is filled in with the 834** current limit. Otherwise the limit is set to the larger of the value 835** of the integer pointed to and the current database size. The integer 836** pointed to is set to the new limit. 837** 838** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 839** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 840** extends and truncates the database file in chunks of a size specified 841** by the user. The fourth argument to [sqlite3_file_control()] should 842** point to an integer (type int) containing the new chunk-size to use 843** for the nominated database. Allocating database file space in large 844** chunks (say 1MB at a time), may reduce file-system fragmentation and 845** improve performance on some systems. 846** 847** <li>[[SQLITE_FCNTL_FILE_POINTER]] 848** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 849** to the [sqlite3_file] object associated with a particular database 850** connection. See also [SQLITE_FCNTL_JOURNAL_POINTER]. 851** 852** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]] 853** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer 854** to the [sqlite3_file] object associated with the journal file (either 855** the [rollback journal] or the [write-ahead log]) for a particular database 856** connection. See also [SQLITE_FCNTL_FILE_POINTER]. 857** 858** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 859** No longer in use. 860** 861** <li>[[SQLITE_FCNTL_SYNC]] 862** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and 863** sent to the VFS immediately before the xSync method is invoked on a 864** database file descriptor. Or, if the xSync method is not invoked 865** because the user has configured SQLite with 866** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 867** of the xSync method. In most cases, the pointer argument passed with 868** this file-control is NULL. However, if the database file is being synced 869** as part of a multi-database commit, the argument points to a nul-terminated 870** string containing the transactions master-journal file name. VFSes that 871** do not need this signal should silently ignore this opcode. Applications 872** should not call [sqlite3_file_control()] with this opcode as doing so may 873** disrupt the operation of the specialized VFSes that do require it. 874** 875** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]] 876** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite 877** and sent to the VFS after a transaction has been committed immediately 878** but before the database is unlocked. VFSes that do not need this signal 879** should silently ignore this opcode. Applications should not call 880** [sqlite3_file_control()] with this opcode as doing so may disrupt the 881** operation of the specialized VFSes that do require it. 882** 883** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 884** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 885** retry counts and intervals for certain disk I/O operations for the 886** windows [VFS] in order to provide robustness in the presence of 887** anti-virus programs. By default, the windows VFS will retry file read, 888** file write, and file delete operations up to 10 times, with a delay 889** of 25 milliseconds before the first retry and with the delay increasing 890** by an additional 25 milliseconds with each subsequent retry. This 891** opcode allows these two values (10 retries and 25 milliseconds of delay) 892** to be adjusted. The values are changed for all database connections 893** within the same process. The argument is a pointer to an array of two 894** integers where the first integer is the new retry count and the second 895** integer is the delay. If either integer is negative, then the setting 896** is not changed but instead the prior value of that setting is written 897** into the array entry, allowing the current retry settings to be 898** interrogated. The zDbName parameter is ignored. 899** 900** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 901** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 902** persistent [WAL | Write Ahead Log] setting. By default, the auxiliary 903** write ahead log ([WAL file]) and shared memory 904** files used for transaction control 905** are automatically deleted when the latest connection to the database 906** closes. Setting persistent WAL mode causes those files to persist after 907** close. Persisting the files is useful when other processes that do not 908** have write permission on the directory containing the database file want 909** to read the database file, as the WAL and shared memory files must exist 910** in order for the database to be readable. The fourth parameter to 911** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 912** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 913** WAL mode. If the integer is -1, then it is overwritten with the current 914** WAL persistence setting. 915** 916** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 917** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 918** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 919** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 920** xDeviceCharacteristics methods. The fourth parameter to 921** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 922** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 923** mode. If the integer is -1, then it is overwritten with the current 924** zero-damage mode setting. 925** 926** <li>[[SQLITE_FCNTL_OVERWRITE]] 927** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 928** a write transaction to indicate that, unless it is rolled back for some 929** reason, the entire database file will be overwritten by the current 930** transaction. This is used by VACUUM operations. 931** 932** <li>[[SQLITE_FCNTL_VFSNAME]] 933** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 934** all [VFSes] in the VFS stack. The names are of all VFS shims and the 935** final bottom-level VFS are written into memory obtained from 936** [sqlite3_malloc()] and the result is stored in the char* variable 937** that the fourth parameter of [sqlite3_file_control()] points to. 938** The caller is responsible for freeing the memory when done. As with 939** all file-control actions, there is no guarantee that this will actually 940** do anything. Callers should initialize the char* variable to a NULL 941** pointer in case this file-control is not implemented. This file-control 942** is intended for diagnostic use only. 943** 944** <li>[[SQLITE_FCNTL_VFS_POINTER]] 945** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level 946** [VFSes] currently in use. ^(The argument X in 947** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be 948** of type "[sqlite3_vfs] **". This opcodes will set *X 949** to a pointer to the top-level VFS.)^ 950** ^When there are multiple VFS shims in the stack, this opcode finds the 951** upper-most shim only. 952** 953** <li>[[SQLITE_FCNTL_PRAGMA]] 954** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 955** file control is sent to the open [sqlite3_file] object corresponding 956** to the database file to which the pragma statement refers. ^The argument 957** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 958** pointers to strings (char**) in which the second element of the array 959** is the name of the pragma and the third element is the argument to the 960** pragma or NULL if the pragma has no argument. ^The handler for an 961** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 962** of the char** argument point to a string obtained from [sqlite3_mprintf()] 963** or the equivalent and that string will become the result of the pragma or 964** the error message if the pragma fails. ^If the 965** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 966** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 967** file control returns [SQLITE_OK], then the parser assumes that the 968** VFS has handled the PRAGMA itself and the parser generates a no-op 969** prepared statement if result string is NULL, or that returns a copy 970** of the result string if the string is non-NULL. 971** ^If the [SQLITE_FCNTL_PRAGMA] file control returns 972** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 973** that the VFS encountered an error while handling the [PRAGMA] and the 974** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 975** file control occurs at the beginning of pragma statement analysis and so 976** it is able to override built-in [PRAGMA] statements. 977** 978** <li>[[SQLITE_FCNTL_BUSYHANDLER]] 979** ^The [SQLITE_FCNTL_BUSYHANDLER] 980** file-control may be invoked by SQLite on the database file handle 981** shortly after it is opened in order to provide a custom VFS with access 982** to the connections busy-handler callback. The argument is of type (void **) 983** - an array of two (void *) values. The first (void *) actually points 984** to a function of type (int (*)(void *)). In order to invoke the connections 985** busy-handler, this function should be invoked with the second (void *) in 986** the array as the only argument. If it returns non-zero, then the operation 987** should be retried. If it returns zero, the custom VFS should abandon the 988** current operation. 989** 990** <li>[[SQLITE_FCNTL_TEMPFILENAME]] 991** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control 992** to have SQLite generate a 993** temporary filename using the same algorithm that is followed to generate 994** temporary filenames for TEMP tables and other internal uses. The 995** argument should be a char** which will be filled with the filename 996** written into memory obtained from [sqlite3_malloc()]. The caller should 997** invoke [sqlite3_free()] on the result to avoid a memory leak. 998** 999** <li>[[SQLITE_FCNTL_MMAP_SIZE]] 1000** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the 1001** maximum number of bytes that will be used for memory-mapped I/O. 1002** The argument is a pointer to a value of type sqlite3_int64 that 1003** is an advisory maximum number of bytes in the file to memory map. The 1004** pointer is overwritten with the old value. The limit is not changed if 1005** the value originally pointed to is negative, and so the current limit 1006** can be queried by passing in a pointer to a negative number. This 1007** file-control is used internally to implement [PRAGMA mmap_size]. 1008** 1009** <li>[[SQLITE_FCNTL_TRACE]] 1010** The [SQLITE_FCNTL_TRACE] file control provides advisory information 1011** to the VFS about what the higher layers of the SQLite stack are doing. 1012** This file control is used by some VFS activity tracing [shims]. 1013** The argument is a zero-terminated string. Higher layers in the 1014** SQLite stack may generate instances of this file control if 1015** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled. 1016** 1017** <li>[[SQLITE_FCNTL_HAS_MOVED]] 1018** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a 1019** pointer to an integer and it writes a boolean into that integer depending 1020** on whether or not the file has been renamed, moved, or deleted since it 1021** was first opened. 1022** 1023** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]] 1024** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the 1025** underlying native file handle associated with a file handle. This file 1026** control interprets its argument as a pointer to a native file handle and 1027** writes the resulting value there. 1028** 1029** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]] 1030** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging. This 1031** opcode causes the xFileControl method to swap the file handle with the one 1032** pointed to by the pArg argument. This capability is used during testing 1033** and only needs to be supported when SQLITE_TEST is defined. 1034** 1035** <li>[[SQLITE_FCNTL_WAL_BLOCK]] 1036** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might 1037** be advantageous to block on the next WAL lock if the lock is not immediately 1038** available. The WAL subsystem issues this signal during rare 1039** circumstances in order to fix a problem with priority inversion. 1040** Applications should <em>not</em> use this file-control. 1041** 1042** <li>[[SQLITE_FCNTL_ZIPVFS]] 1043** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other 1044** VFS should return SQLITE_NOTFOUND for this opcode. 1045** 1046** <li>[[SQLITE_FCNTL_RBU]] 1047** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by 1048** the RBU extension only. All other VFS should return SQLITE_NOTFOUND for 1049** this opcode. 1050** 1051** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]] 1052** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then 1053** the file descriptor is placed in "batch write mode", which 1054** means all subsequent write operations will be deferred and done 1055** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]. Systems 1056** that do not support batch atomic writes will return SQLITE_NOTFOUND. 1057** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to 1058** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or 1059** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make 1060** no VFS interface calls on the same [sqlite3_file] file descriptor 1061** except for calls to the xWrite method and the xFileControl method 1062** with [SQLITE_FCNTL_SIZE_HINT]. 1063** 1064** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]] 1065** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write 1066** operations since the previous successful call to 1067** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically. 1068** This file control returns [SQLITE_OK] if and only if the writes were 1069** all performed successfully and have been committed to persistent storage. 1070** ^Regardless of whether or not it is successful, this file control takes 1071** the file descriptor out of batch write mode so that all subsequent 1072** write operations are independent. 1073** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without 1074** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1075** 1076** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]] 1077** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write 1078** operations since the previous successful call to 1079** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back. 1080** ^This file control takes the file descriptor out of batch write mode 1081** so that all subsequent write operations are independent. 1082** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without 1083** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]. 1084** 1085** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]] 1086** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode causes attempts to obtain 1087** a file lock using the xLock or xShmLock methods of the VFS to wait 1088** for up to M milliseconds before failing, where M is the single 1089** unsigned integer parameter. 1090** 1091** <li>[[SQLITE_FCNTL_DATA_VERSION]] 1092** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to 1093** a database file. The argument is a pointer to a 32-bit unsigned integer. 1094** The "data version" for the pager is written into the pointer. The 1095** "data version" changes whenever any change occurs to the corresponding 1096** database file, either through SQL statements on the same database 1097** connection or through transactions committed by separate database 1098** connections possibly in other processes. The [sqlite3_total_changes()] 1099** interface can be used to find if any database on the connection has changed, 1100** but that interface responds to changes on TEMP as well as MAIN and does 1101** not provide a mechanism to detect changes to MAIN only. Also, the 1102** [sqlite3_total_changes()] interface responds to internal changes only and 1103** omits changes made by other database connections. The 1104** [PRAGMA data_version] command provide a mechanism to detect changes to 1105** a single attached database that occur due to other database connections, 1106** but omits changes implemented by the database connection on which it is 1107** called. This file control is the only mechanism to detect changes that 1108** happen either internally or externally and that are associated with 1109** a particular attached database. 1110** </ul> 1111*/ 1112#define SQLITE_FCNTL_LOCKSTATE 1 1113#define SQLITE_FCNTL_GET_LOCKPROXYFILE 2 1114#define SQLITE_FCNTL_SET_LOCKPROXYFILE 3 1115#define SQLITE_FCNTL_LAST_ERRNO 4 1116#define SQLITE_FCNTL_SIZE_HINT 5 1117#define SQLITE_FCNTL_CHUNK_SIZE 6 1118#define SQLITE_FCNTL_FILE_POINTER 7 1119#define SQLITE_FCNTL_SYNC_OMITTED 8 1120#define SQLITE_FCNTL_WIN32_AV_RETRY 9 1121#define SQLITE_FCNTL_PERSIST_WAL 10 1122#define SQLITE_FCNTL_OVERWRITE 11 1123#define SQLITE_FCNTL_VFSNAME 12 1124#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 1125#define SQLITE_FCNTL_PRAGMA 14 1126#define SQLITE_FCNTL_BUSYHANDLER 15 1127#define SQLITE_FCNTL_TEMPFILENAME 16 1128#define SQLITE_FCNTL_MMAP_SIZE 18 1129#define SQLITE_FCNTL_TRACE 19 1130#define SQLITE_FCNTL_HAS_MOVED 20 1131#define SQLITE_FCNTL_SYNC 21 1132#define SQLITE_FCNTL_COMMIT_PHASETWO 22 1133#define SQLITE_FCNTL_WIN32_SET_HANDLE 23 1134#define SQLITE_FCNTL_WAL_BLOCK 24 1135#define SQLITE_FCNTL_ZIPVFS 25 1136#define SQLITE_FCNTL_RBU 26 1137#define SQLITE_FCNTL_VFS_POINTER 27 1138#define SQLITE_FCNTL_JOURNAL_POINTER 28 1139#define SQLITE_FCNTL_WIN32_GET_HANDLE 29 1140#define SQLITE_FCNTL_PDB 30 1141#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE 31 1142#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE 32 1143#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE 33 1144#define SQLITE_FCNTL_LOCK_TIMEOUT 34 1145#define SQLITE_FCNTL_DATA_VERSION 35 1146#define SQLITE_FCNTL_SIZE_LIMIT 36 1147 1148/* deprecated names */ 1149#define SQLITE_GET_LOCKPROXYFILE SQLITE_FCNTL_GET_LOCKPROXYFILE 1150#define SQLITE_SET_LOCKPROXYFILE SQLITE_FCNTL_SET_LOCKPROXYFILE 1151#define SQLITE_LAST_ERRNO SQLITE_FCNTL_LAST_ERRNO 1152 1153 1154/* 1155** CAPI3REF: Mutex Handle 1156** 1157** The mutex module within SQLite defines [sqlite3_mutex] to be an 1158** abstract type for a mutex object. The SQLite core never looks 1159** at the internal representation of an [sqlite3_mutex]. It only 1160** deals with pointers to the [sqlite3_mutex] object. 1161** 1162** Mutexes are created using [sqlite3_mutex_alloc()]. 1163*/ 1164typedef struct sqlite3_mutex sqlite3_mutex; 1165 1166/* 1167** CAPI3REF: Loadable Extension Thunk 1168** 1169** A pointer to the opaque sqlite3_api_routines structure is passed as 1170** the third parameter to entry points of [loadable extensions]. This 1171** structure must be typedefed in order to work around compiler warnings 1172** on some platforms. 1173*/ 1174typedef struct sqlite3_api_routines sqlite3_api_routines; 1175 1176/* 1177** CAPI3REF: OS Interface Object 1178** 1179** An instance of the sqlite3_vfs object defines the interface between 1180** the SQLite core and the underlying operating system. The "vfs" 1181** in the name of the object stands for "virtual file system". See 1182** the [VFS | VFS documentation] for further information. 1183** 1184** The VFS interface is sometimes extended by adding new methods onto 1185** the end. Each time such an extension occurs, the iVersion field 1186** is incremented. The iVersion value started out as 1 in 1187** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2 1188** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased 1189** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6]. Additional fields 1190** may be appended to the sqlite3_vfs object and the iVersion value 1191** may increase again in future versions of SQLite. 1192** Note that the structure 1193** of the sqlite3_vfs object changes in the transition from 1194** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0] 1195** and yet the iVersion field was not modified. 1196** 1197** The szOsFile field is the size of the subclassed [sqlite3_file] 1198** structure used by this VFS. mxPathname is the maximum length of 1199** a pathname in this VFS. 1200** 1201** Registered sqlite3_vfs objects are kept on a linked list formed by 1202** the pNext pointer. The [sqlite3_vfs_register()] 1203** and [sqlite3_vfs_unregister()] interfaces manage this list 1204** in a thread-safe way. The [sqlite3_vfs_find()] interface 1205** searches the list. Neither the application code nor the VFS 1206** implementation should use the pNext pointer. 1207** 1208** The pNext field is the only field in the sqlite3_vfs 1209** structure that SQLite will ever modify. SQLite will only access 1210** or modify this field while holding a particular static mutex. 1211** The application should never modify anything within the sqlite3_vfs 1212** object once the object has been registered. 1213** 1214** The zName field holds the name of the VFS module. The name must 1215** be unique across all VFS modules. 1216** 1217** [[sqlite3_vfs.xOpen]] 1218** ^SQLite guarantees that the zFilename parameter to xOpen 1219** is either a NULL pointer or string obtained 1220** from xFullPathname() with an optional suffix added. 1221** ^If a suffix is added to the zFilename parameter, it will 1222** consist of a single "-" character followed by no more than 1223** 11 alphanumeric and/or "-" characters. 1224** ^SQLite further guarantees that 1225** the string will be valid and unchanged until xClose() is 1226** called. Because of the previous sentence, 1227** the [sqlite3_file] can safely store a pointer to the 1228** filename if it needs to remember the filename for some reason. 1229** If the zFilename parameter to xOpen is a NULL pointer then xOpen 1230** must invent its own temporary name for the file. ^Whenever the 1231** xFilename parameter is NULL it will also be the case that the 1232** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 1233** 1234** The flags argument to xOpen() includes all bits set in 1235** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 1236** or [sqlite3_open16()] is used, then flags includes at least 1237** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 1238** If xOpen() opens a file read-only then it sets *pOutFlags to 1239** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 1240** 1241** ^(SQLite will also add one of the following flags to the xOpen() 1242** call, depending on the object being opened: 1243** 1244** <ul> 1245** <li> [SQLITE_OPEN_MAIN_DB] 1246** <li> [SQLITE_OPEN_MAIN_JOURNAL] 1247** <li> [SQLITE_OPEN_TEMP_DB] 1248** <li> [SQLITE_OPEN_TEMP_JOURNAL] 1249** <li> [SQLITE_OPEN_TRANSIENT_DB] 1250** <li> [SQLITE_OPEN_SUBJOURNAL] 1251** <li> [SQLITE_OPEN_MASTER_JOURNAL] 1252** <li> [SQLITE_OPEN_WAL] 1253** </ul>)^ 1254** 1255** The file I/O implementation can use the object type flags to 1256** change the way it deals with files. For example, an application 1257** that does not care about crash recovery or rollback might make 1258** the open of a journal file a no-op. Writes to this journal would 1259** also be no-ops, and any attempt to read the journal would return 1260** SQLITE_IOERR. Or the implementation might recognize that a database 1261** file will be doing page-aligned sector reads and writes in a random 1262** order and set up its I/O subsystem accordingly. 1263** 1264** SQLite might also add one of the following flags to the xOpen method: 1265** 1266** <ul> 1267** <li> [SQLITE_OPEN_DELETEONCLOSE] 1268** <li> [SQLITE_OPEN_EXCLUSIVE] 1269** </ul> 1270** 1271** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 1272** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 1273** will be set for TEMP databases and their journals, transient 1274** databases, and subjournals. 1275** 1276** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 1277** with the [SQLITE_OPEN_CREATE] flag, which are both directly 1278** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 1279** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 1280** SQLITE_OPEN_CREATE, is used to indicate that file should always 1281** be created, and that it is an error if it already exists. 1282** It is <i>not</i> used to indicate the file should be opened 1283** for exclusive access. 1284** 1285** ^At least szOsFile bytes of memory are allocated by SQLite 1286** to hold the [sqlite3_file] structure passed as the third 1287** argument to xOpen. The xOpen method does not have to 1288** allocate the structure; it should just fill it in. Note that 1289** the xOpen method must set the sqlite3_file.pMethods to either 1290** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 1291** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 1292** element will be valid after xOpen returns regardless of the success 1293** or failure of the xOpen call. 1294** 1295** [[sqlite3_vfs.xAccess]] 1296** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 1297** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 1298** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 1299** to test whether a file is at least readable. The SQLITE_ACCESS_READ 1300** flag is never actually used and is not implemented in the built-in 1301** VFSes of SQLite. The file is named by the second argument and can be a 1302** directory. The xAccess method returns [SQLITE_OK] on success or some 1303** non-zero error code if there is an I/O error or if the name of 1304** the file given in the second argument is illegal. If SQLITE_OK 1305** is returned, then non-zero or zero is written into *pResOut to indicate 1306** whether or not the file is accessible. 1307** 1308** ^SQLite will always allocate at least mxPathname+1 bytes for the 1309** output buffer xFullPathname. The exact size of the output buffer 1310** is also passed as a parameter to both methods. If the output buffer 1311** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 1312** handled as a fatal error by SQLite, vfs implementations should endeavor 1313** to prevent this by setting mxPathname to a sufficiently large value. 1314** 1315** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 1316** interfaces are not strictly a part of the filesystem, but they are 1317** included in the VFS structure for completeness. 1318** The xRandomness() function attempts to return nBytes bytes 1319** of good-quality randomness into zOut. The return value is 1320** the actual number of bytes of randomness obtained. 1321** The xSleep() method causes the calling thread to sleep for at 1322** least the number of microseconds given. ^The xCurrentTime() 1323** method returns a Julian Day Number for the current date and time as 1324** a floating point value. 1325** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1326** Day Number multiplied by 86400000 (the number of milliseconds in 1327** a 24-hour day). 1328** ^SQLite will use the xCurrentTimeInt64() method to get the current 1329** date and time if that method is available (if iVersion is 2 or 1330** greater and the function pointer is not NULL) and will fall back 1331** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1332** 1333** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1334** are not used by the SQLite core. These optional interfaces are provided 1335** by some VFSes to facilitate testing of the VFS code. By overriding 1336** system calls with functions under its control, a test program can 1337** simulate faults and error conditions that would otherwise be difficult 1338** or impossible to induce. The set of system calls that can be overridden 1339** varies from one VFS to another, and from one version of the same VFS to the 1340** next. Applications that use these interfaces must be prepared for any 1341** or all of these interfaces to be NULL or for their behavior to change 1342** from one release to the next. Applications must not attempt to access 1343** any of these methods if the iVersion of the VFS is less than 3. 1344*/ 1345typedef struct sqlite3_vfs sqlite3_vfs; 1346typedef void (*sqlite3_syscall_ptr)(void); 1347struct sqlite3_vfs { 1348 int iVersion; /* Structure version number (currently 3) */ 1349 int szOsFile; /* Size of subclassed sqlite3_file */ 1350 int mxPathname; /* Maximum file pathname length */ 1351 sqlite3_vfs *pNext; /* Next registered VFS */ 1352 const char *zName; /* Name of this virtual file system */ 1353 void *pAppData; /* Pointer to application-specific data */ 1354 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1355 int flags, int *pOutFlags); 1356 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1357 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1358 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1359 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1360 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1361 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1362 void (*xDlClose)(sqlite3_vfs*, void*); 1363 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1364 int (*xSleep)(sqlite3_vfs*, int microseconds); 1365 int (*xCurrentTime)(sqlite3_vfs*, double*); 1366 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1367 /* 1368 ** The methods above are in version 1 of the sqlite_vfs object 1369 ** definition. Those that follow are added in version 2 or later 1370 */ 1371 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1372 /* 1373 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1374 ** Those below are for version 3 and greater. 1375 */ 1376 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1377 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1378 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1379 /* 1380 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1381 ** New fields may be appended in future versions. The iVersion 1382 ** value will increment whenever this happens. 1383 */ 1384}; 1385 1386/* 1387** CAPI3REF: Flags for the xAccess VFS method 1388** 1389** These integer constants can be used as the third parameter to 1390** the xAccess method of an [sqlite3_vfs] object. They determine 1391** what kind of permissions the xAccess method is looking for. 1392** With SQLITE_ACCESS_EXISTS, the xAccess method 1393** simply checks whether the file exists. 1394** With SQLITE_ACCESS_READWRITE, the xAccess method 1395** checks whether the named directory is both readable and writable 1396** (in other words, if files can be added, removed, and renamed within 1397** the directory). 1398** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1399** [temp_store_directory pragma], though this could change in a future 1400** release of SQLite. 1401** With SQLITE_ACCESS_READ, the xAccess method 1402** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1403** currently unused, though it might be used in a future release of 1404** SQLite. 1405*/ 1406#define SQLITE_ACCESS_EXISTS 0 1407#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1408#define SQLITE_ACCESS_READ 2 /* Unused */ 1409 1410/* 1411** CAPI3REF: Flags for the xShmLock VFS method 1412** 1413** These integer constants define the various locking operations 1414** allowed by the xShmLock method of [sqlite3_io_methods]. The 1415** following are the only legal combinations of flags to the 1416** xShmLock method: 1417** 1418** <ul> 1419** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1420** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1421** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1422** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1423** </ul> 1424** 1425** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1426** was given on the corresponding lock. 1427** 1428** The xShmLock method can transition between unlocked and SHARED or 1429** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1430** and EXCLUSIVE. 1431*/ 1432#define SQLITE_SHM_UNLOCK 1 1433#define SQLITE_SHM_LOCK 2 1434#define SQLITE_SHM_SHARED 4 1435#define SQLITE_SHM_EXCLUSIVE 8 1436 1437/* 1438** CAPI3REF: Maximum xShmLock index 1439** 1440** The xShmLock method on [sqlite3_io_methods] may use values 1441** between 0 and this upper bound as its "offset" argument. 1442** The SQLite core will never attempt to acquire or release a 1443** lock outside of this range 1444*/ 1445#define SQLITE_SHM_NLOCK 8 1446 1447 1448/* 1449** CAPI3REF: Initialize The SQLite Library 1450** 1451** ^The sqlite3_initialize() routine initializes the 1452** SQLite library. ^The sqlite3_shutdown() routine 1453** deallocates any resources that were allocated by sqlite3_initialize(). 1454** These routines are designed to aid in process initialization and 1455** shutdown on embedded systems. Workstation applications using 1456** SQLite normally do not need to invoke either of these routines. 1457** 1458** A call to sqlite3_initialize() is an "effective" call if it is 1459** the first time sqlite3_initialize() is invoked during the lifetime of 1460** the process, or if it is the first time sqlite3_initialize() is invoked 1461** following a call to sqlite3_shutdown(). ^(Only an effective call 1462** of sqlite3_initialize() does any initialization. All other calls 1463** are harmless no-ops.)^ 1464** 1465** A call to sqlite3_shutdown() is an "effective" call if it is the first 1466** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1467** an effective call to sqlite3_shutdown() does any deinitialization. 1468** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1469** 1470** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1471** is not. The sqlite3_shutdown() interface must only be called from a 1472** single thread. All open [database connections] must be closed and all 1473** other SQLite resources must be deallocated prior to invoking 1474** sqlite3_shutdown(). 1475** 1476** Among other things, ^sqlite3_initialize() will invoke 1477** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1478** will invoke sqlite3_os_end(). 1479** 1480** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1481** ^If for some reason, sqlite3_initialize() is unable to initialize 1482** the library (perhaps it is unable to allocate a needed resource such 1483** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1484** 1485** ^The sqlite3_initialize() routine is called internally by many other 1486** SQLite interfaces so that an application usually does not need to 1487** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1488** calls sqlite3_initialize() so the SQLite library will be automatically 1489** initialized when [sqlite3_open()] is called if it has not be initialized 1490** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1491** compile-time option, then the automatic calls to sqlite3_initialize() 1492** are omitted and the application must call sqlite3_initialize() directly 1493** prior to using any other SQLite interface. For maximum portability, 1494** it is recommended that applications always invoke sqlite3_initialize() 1495** directly prior to using any other SQLite interface. Future releases 1496** of SQLite may require this. In other words, the behavior exhibited 1497** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1498** default behavior in some future release of SQLite. 1499** 1500** The sqlite3_os_init() routine does operating-system specific 1501** initialization of the SQLite library. The sqlite3_os_end() 1502** routine undoes the effect of sqlite3_os_init(). Typical tasks 1503** performed by these routines include allocation or deallocation 1504** of static resources, initialization of global variables, 1505** setting up a default [sqlite3_vfs] module, or setting up 1506** a default configuration using [sqlite3_config()]. 1507** 1508** The application should never invoke either sqlite3_os_init() 1509** or sqlite3_os_end() directly. The application should only invoke 1510** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1511** interface is called automatically by sqlite3_initialize() and 1512** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1513** implementations for sqlite3_os_init() and sqlite3_os_end() 1514** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1515** When [custom builds | built for other platforms] 1516** (using the [SQLITE_OS_OTHER=1] compile-time 1517** option) the application must supply a suitable implementation for 1518** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1519** implementation of sqlite3_os_init() or sqlite3_os_end() 1520** must return [SQLITE_OK] on success and some other [error code] upon 1521** failure. 1522*/ 1523int sqlite3_initialize(void); 1524int sqlite3_shutdown(void); 1525int sqlite3_os_init(void); 1526int sqlite3_os_end(void); 1527 1528/* 1529** CAPI3REF: Configuring The SQLite Library 1530** 1531** The sqlite3_config() interface is used to make global configuration 1532** changes to SQLite in order to tune SQLite to the specific needs of 1533** the application. The default configuration is recommended for most 1534** applications and so this routine is usually not necessary. It is 1535** provided to support rare applications with unusual needs. 1536** 1537** <b>The sqlite3_config() interface is not threadsafe. The application 1538** must ensure that no other SQLite interfaces are invoked by other 1539** threads while sqlite3_config() is running.</b> 1540** 1541** The sqlite3_config() interface 1542** may only be invoked prior to library initialization using 1543** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1544** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1545** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1546** Note, however, that ^sqlite3_config() can be called as part of the 1547** implementation of an application-defined [sqlite3_os_init()]. 1548** 1549** The first argument to sqlite3_config() is an integer 1550** [configuration option] that determines 1551** what property of SQLite is to be configured. Subsequent arguments 1552** vary depending on the [configuration option] 1553** in the first argument. 1554** 1555** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1556** ^If the option is unknown or SQLite is unable to set the option 1557** then this routine returns a non-zero [error code]. 1558*/ 1559int sqlite3_config(int, ...); 1560 1561/* 1562** CAPI3REF: Configure database connections 1563** METHOD: sqlite3 1564** 1565** The sqlite3_db_config() interface is used to make configuration 1566** changes to a [database connection]. The interface is similar to 1567** [sqlite3_config()] except that the changes apply to a single 1568** [database connection] (specified in the first argument). 1569** 1570** The second argument to sqlite3_db_config(D,V,...) is the 1571** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1572** that indicates what aspect of the [database connection] is being configured. 1573** Subsequent arguments vary depending on the configuration verb. 1574** 1575** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1576** the call is considered successful. 1577*/ 1578int sqlite3_db_config(sqlite3*, int op, ...); 1579 1580/* 1581** CAPI3REF: Memory Allocation Routines 1582** 1583** An instance of this object defines the interface between SQLite 1584** and low-level memory allocation routines. 1585** 1586** This object is used in only one place in the SQLite interface. 1587** A pointer to an instance of this object is the argument to 1588** [sqlite3_config()] when the configuration option is 1589** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1590** By creating an instance of this object 1591** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1592** during configuration, an application can specify an alternative 1593** memory allocation subsystem for SQLite to use for all of its 1594** dynamic memory needs. 1595** 1596** Note that SQLite comes with several [built-in memory allocators] 1597** that are perfectly adequate for the overwhelming majority of applications 1598** and that this object is only useful to a tiny minority of applications 1599** with specialized memory allocation requirements. This object is 1600** also used during testing of SQLite in order to specify an alternative 1601** memory allocator that simulates memory out-of-memory conditions in 1602** order to verify that SQLite recovers gracefully from such 1603** conditions. 1604** 1605** The xMalloc, xRealloc, and xFree methods must work like the 1606** malloc(), realloc() and free() functions from the standard C library. 1607** ^SQLite guarantees that the second argument to 1608** xRealloc is always a value returned by a prior call to xRoundup. 1609** 1610** xSize should return the allocated size of a memory allocation 1611** previously obtained from xMalloc or xRealloc. The allocated size 1612** is always at least as big as the requested size but may be larger. 1613** 1614** The xRoundup method returns what would be the allocated size of 1615** a memory allocation given a particular requested size. Most memory 1616** allocators round up memory allocations at least to the next multiple 1617** of 8. Some allocators round up to a larger multiple or to a power of 2. 1618** Every memory allocation request coming in through [sqlite3_malloc()] 1619** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1620** that causes the corresponding memory allocation to fail. 1621** 1622** The xInit method initializes the memory allocator. For example, 1623** it might allocate any require mutexes or initialize internal data 1624** structures. The xShutdown method is invoked (indirectly) by 1625** [sqlite3_shutdown()] and should deallocate any resources acquired 1626** by xInit. The pAppData pointer is used as the only parameter to 1627** xInit and xShutdown. 1628** 1629** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1630** the xInit method, so the xInit method need not be threadsafe. The 1631** xShutdown method is only called from [sqlite3_shutdown()] so it does 1632** not need to be threadsafe either. For all other methods, SQLite 1633** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1634** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1635** it is by default) and so the methods are automatically serialized. 1636** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1637** methods must be threadsafe or else make their own arrangements for 1638** serialization. 1639** 1640** SQLite will never invoke xInit() more than once without an intervening 1641** call to xShutdown(). 1642*/ 1643typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1644struct sqlite3_mem_methods { 1645 void *(*xMalloc)(int); /* Memory allocation function */ 1646 void (*xFree)(void*); /* Free a prior allocation */ 1647 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1648 int (*xSize)(void*); /* Return the size of an allocation */ 1649 int (*xRoundup)(int); /* Round up request size to allocation size */ 1650 int (*xInit)(void*); /* Initialize the memory allocator */ 1651 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1652 void *pAppData; /* Argument to xInit() and xShutdown() */ 1653}; 1654 1655/* 1656** CAPI3REF: Configuration Options 1657** KEYWORDS: {configuration option} 1658** 1659** These constants are the available integer configuration options that 1660** can be passed as the first argument to the [sqlite3_config()] interface. 1661** 1662** New configuration options may be added in future releases of SQLite. 1663** Existing configuration options might be discontinued. Applications 1664** should check the return code from [sqlite3_config()] to make sure that 1665** the call worked. The [sqlite3_config()] interface will return a 1666** non-zero [error code] if a discontinued or unsupported configuration option 1667** is invoked. 1668** 1669** <dl> 1670** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1671** <dd>There are no arguments to this option. ^This option sets the 1672** [threading mode] to Single-thread. In other words, it disables 1673** all mutexing and puts SQLite into a mode where it can only be used 1674** by a single thread. ^If SQLite is compiled with 1675** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1676** it is not possible to change the [threading mode] from its default 1677** value of Single-thread and so [sqlite3_config()] will return 1678** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1679** configuration option.</dd> 1680** 1681** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1682** <dd>There are no arguments to this option. ^This option sets the 1683** [threading mode] to Multi-thread. In other words, it disables 1684** mutexing on [database connection] and [prepared statement] objects. 1685** The application is responsible for serializing access to 1686** [database connections] and [prepared statements]. But other mutexes 1687** are enabled so that SQLite will be safe to use in a multi-threaded 1688** environment as long as no two threads attempt to use the same 1689** [database connection] at the same time. ^If SQLite is compiled with 1690** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1691** it is not possible to set the Multi-thread [threading mode] and 1692** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1693** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1694** 1695** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1696** <dd>There are no arguments to this option. ^This option sets the 1697** [threading mode] to Serialized. In other words, this option enables 1698** all mutexes including the recursive 1699** mutexes on [database connection] and [prepared statement] objects. 1700** In this mode (which is the default when SQLite is compiled with 1701** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1702** to [database connections] and [prepared statements] so that the 1703** application is free to use the same [database connection] or the 1704** same [prepared statement] in different threads at the same time. 1705** ^If SQLite is compiled with 1706** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1707** it is not possible to set the Serialized [threading mode] and 1708** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1709** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1710** 1711** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1712** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 1713** a pointer to an instance of the [sqlite3_mem_methods] structure. 1714** The argument specifies 1715** alternative low-level memory allocation routines to be used in place of 1716** the memory allocation routines built into SQLite.)^ ^SQLite makes 1717** its own private copy of the content of the [sqlite3_mem_methods] structure 1718** before the [sqlite3_config()] call returns.</dd> 1719** 1720** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1721** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which 1722** is a pointer to an instance of the [sqlite3_mem_methods] structure. 1723** The [sqlite3_mem_methods] 1724** structure is filled with the currently defined memory allocation routines.)^ 1725** This option can be used to overload the default memory allocation 1726** routines with a wrapper that simulations memory allocation failure or 1727** tracks memory usage, for example. </dd> 1728** 1729** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt> 1730** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of 1731** type int, interpreted as a boolean, which if true provides a hint to 1732** SQLite that it should avoid large memory allocations if possible. 1733** SQLite will run faster if it is free to make large memory allocations, 1734** but some application might prefer to run slower in exchange for 1735** guarantees about memory fragmentation that are possible if large 1736** allocations are avoided. This hint is normally off. 1737** </dd> 1738** 1739** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1740** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int, 1741** interpreted as a boolean, which enables or disables the collection of 1742** memory allocation statistics. ^(When memory allocation statistics are 1743** disabled, the following SQLite interfaces become non-operational: 1744** <ul> 1745** <li> [sqlite3_memory_used()] 1746** <li> [sqlite3_memory_highwater()] 1747** <li> [sqlite3_soft_heap_limit64()] 1748** <li> [sqlite3_status64()] 1749** </ul>)^ 1750** ^Memory allocation statistics are enabled by default unless SQLite is 1751** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1752** allocation statistics are disabled by default. 1753** </dd> 1754** 1755** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1756** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used. 1757** </dd> 1758** 1759** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1760** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool 1761** that SQLite can use for the database page cache with the default page 1762** cache implementation. 1763** This configuration option is a no-op if an application-define page 1764** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2]. 1765** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to 1766** 8-byte aligned memory (pMem), the size of each page cache line (sz), 1767** and the number of cache lines (N). 1768** The sz argument should be the size of the largest database page 1769** (a power of two between 512 and 65536) plus some extra bytes for each 1770** page header. ^The number of extra bytes needed by the page header 1771** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ]. 1772** ^It is harmless, apart from the wasted memory, 1773** for the sz parameter to be larger than necessary. The pMem 1774** argument must be either a NULL pointer or a pointer to an 8-byte 1775** aligned block of memory of at least sz*N bytes, otherwise 1776** subsequent behavior is undefined. 1777** ^When pMem is not NULL, SQLite will strive to use the memory provided 1778** to satisfy page cache needs, falling back to [sqlite3_malloc()] if 1779** a page cache line is larger than sz bytes or if all of the pMem buffer 1780** is exhausted. 1781** ^If pMem is NULL and N is non-zero, then each database connection 1782** does an initial bulk allocation for page cache memory 1783** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or 1784** of -1024*N bytes if N is negative, . ^If additional 1785** page cache memory is needed beyond what is provided by the initial 1786** allocation, then SQLite goes to [sqlite3_malloc()] separately for each 1787** additional cache line. </dd> 1788** 1789** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1790** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 1791** that SQLite will use for all of its dynamic memory allocation needs 1792** beyond those provided for by [SQLITE_CONFIG_PAGECACHE]. 1793** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled 1794** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns 1795** [SQLITE_ERROR] if invoked otherwise. 1796** ^There are three arguments to SQLITE_CONFIG_HEAP: 1797** An 8-byte aligned pointer to the memory, 1798** the number of bytes in the memory buffer, and the minimum allocation size. 1799** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1800** to using its default memory allocator (the system malloc() implementation), 1801** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1802** memory pointer is not NULL then the alternative memory 1803** allocator is engaged to handle all of SQLites memory allocation needs. 1804** The first pointer (the memory pointer) must be aligned to an 8-byte 1805** boundary or subsequent behavior of SQLite will be undefined. 1806** The minimum allocation size is capped at 2**12. Reasonable values 1807** for the minimum allocation size are 2**5 through 2**8.</dd> 1808** 1809** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1810** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a 1811** pointer to an instance of the [sqlite3_mutex_methods] structure. 1812** The argument specifies alternative low-level mutex routines to be used 1813** in place the mutex routines built into SQLite.)^ ^SQLite makes a copy of 1814** the content of the [sqlite3_mutex_methods] structure before the call to 1815** [sqlite3_config()] returns. ^If SQLite is compiled with 1816** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1817** the entire mutexing subsystem is omitted from the build and hence calls to 1818** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1819** return [SQLITE_ERROR].</dd> 1820** 1821** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1822** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which 1823** is a pointer to an instance of the [sqlite3_mutex_methods] structure. The 1824** [sqlite3_mutex_methods] 1825** structure is filled with the currently defined mutex routines.)^ 1826** This option can be used to overload the default mutex allocation 1827** routines with a wrapper used to track mutex usage for performance 1828** profiling or testing, for example. ^If SQLite is compiled with 1829** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1830** the entire mutexing subsystem is omitted from the build and hence calls to 1831** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1832** return [SQLITE_ERROR].</dd> 1833** 1834** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1835** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine 1836** the default size of lookaside memory on each [database connection]. 1837** The first argument is the 1838** size of each lookaside buffer slot and the second is the number of 1839** slots allocated to each database connection.)^ ^(SQLITE_CONFIG_LOOKASIDE 1840** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1841** option to [sqlite3_db_config()] can be used to change the lookaside 1842** configuration on individual connections.)^ </dd> 1843** 1844** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1845** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 1846** a pointer to an [sqlite3_pcache_methods2] object. This object specifies 1847** the interface to a custom page cache implementation.)^ 1848** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd> 1849** 1850** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1851** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which 1852** is a pointer to an [sqlite3_pcache_methods2] object. SQLite copies of 1853** the current page cache implementation into that object.)^ </dd> 1854** 1855** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1856** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite 1857** global [error log]. 1858** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1859** function with a call signature of void(*)(void*,int,const char*), 1860** and a pointer to void. ^If the function pointer is not NULL, it is 1861** invoked by [sqlite3_log()] to process each logging event. ^If the 1862** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1863** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1864** passed through as the first parameter to the application-defined logger 1865** function whenever that function is invoked. ^The second parameter to 1866** the logger function is a copy of the first parameter to the corresponding 1867** [sqlite3_log()] call and is intended to be a [result code] or an 1868** [extended result code]. ^The third parameter passed to the logger is 1869** log message after formatting via [sqlite3_snprintf()]. 1870** The SQLite logging interface is not reentrant; the logger function 1871** supplied by the application must not invoke any SQLite interface. 1872** In a multi-threaded application, the application-defined logger 1873** function must be threadsafe. </dd> 1874** 1875** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1876** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int. 1877** If non-zero, then URI handling is globally enabled. If the parameter is zero, 1878** then URI handling is globally disabled.)^ ^If URI handling is globally 1879** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()], 1880** [sqlite3_open16()] or 1881** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1882** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1883** connection is opened. ^If it is globally disabled, filenames are 1884** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1885** database connection is opened. ^(By default, URI handling is globally 1886** disabled. The default value may be changed by compiling with the 1887** [SQLITE_USE_URI] symbol defined.)^ 1888** 1889** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN 1890** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer 1891** argument which is interpreted as a boolean in order to enable or disable 1892** the use of covering indices for full table scans in the query optimizer. 1893** ^The default setting is determined 1894** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on" 1895** if that compile-time option is omitted. 1896** The ability to disable the use of covering indices for full table scans 1897** is because some incorrectly coded legacy applications might malfunction 1898** when the optimization is enabled. Providing the ability to 1899** disable the optimization allows the older, buggy application code to work 1900** without change even with newer versions of SQLite. 1901** 1902** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1903** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE 1904** <dd> These options are obsolete and should not be used by new code. 1905** They are retained for backwards compatibility but are now no-ops. 1906** </dd> 1907** 1908** [[SQLITE_CONFIG_SQLLOG]] 1909** <dt>SQLITE_CONFIG_SQLLOG 1910** <dd>This option is only available if sqlite is compiled with the 1911** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should 1912** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int). 1913** The second should be of type (void*). The callback is invoked by the library 1914** in three separate circumstances, identified by the value passed as the 1915** fourth parameter. If the fourth parameter is 0, then the database connection 1916** passed as the second argument has just been opened. The third argument 1917** points to a buffer containing the name of the main database file. If the 1918** fourth parameter is 1, then the SQL statement that the third parameter 1919** points to has just been executed. Or, if the fourth parameter is 2, then 1920** the connection being passed as the second parameter is being closed. The 1921** third parameter is passed NULL In this case. An example of using this 1922** configuration option can be seen in the "test_sqllog.c" source file in 1923** the canonical SQLite source tree.</dd> 1924** 1925** [[SQLITE_CONFIG_MMAP_SIZE]] 1926** <dt>SQLITE_CONFIG_MMAP_SIZE 1927** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values 1928** that are the default mmap size limit (the default setting for 1929** [PRAGMA mmap_size]) and the maximum allowed mmap size limit. 1930** ^The default setting can be overridden by each database connection using 1931** either the [PRAGMA mmap_size] command, or by using the 1932** [SQLITE_FCNTL_MMAP_SIZE] file control. ^(The maximum allowed mmap size 1933** will be silently truncated if necessary so that it does not exceed the 1934** compile-time maximum mmap size set by the 1935** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^ 1936** ^If either argument to this option is negative, then that argument is 1937** changed to its compile-time default. 1938** 1939** [[SQLITE_CONFIG_WIN32_HEAPSIZE]] 1940** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE 1941** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is 1942** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro 1943** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value 1944** that specifies the maximum size of the created heap. 1945** 1946** [[SQLITE_CONFIG_PCACHE_HDRSZ]] 1947** <dt>SQLITE_CONFIG_PCACHE_HDRSZ 1948** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which 1949** is a pointer to an integer and writes into that integer the number of extra 1950** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE]. 1951** The amount of extra space required can change depending on the compiler, 1952** target platform, and SQLite version. 1953** 1954** [[SQLITE_CONFIG_PMASZ]] 1955** <dt>SQLITE_CONFIG_PMASZ 1956** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which 1957** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded 1958** sorter to that integer. The default minimum PMA Size is set by the 1959** [SQLITE_SORTER_PMASZ] compile-time option. New threads are launched 1960** to help with sort operations when multithreaded sorting 1961** is enabled (using the [PRAGMA threads] command) and the amount of content 1962** to be sorted exceeds the page size times the minimum of the 1963** [PRAGMA cache_size] setting and this value. 1964** 1965** [[SQLITE_CONFIG_STMTJRNL_SPILL]] 1966** <dt>SQLITE_CONFIG_STMTJRNL_SPILL 1967** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which 1968** becomes the [statement journal] spill-to-disk threshold. 1969** [Statement journals] are held in memory until their size (in bytes) 1970** exceeds this threshold, at which point they are written to disk. 1971** Or if the threshold is -1, statement journals are always held 1972** exclusively in memory. 1973** Since many statement journals never become large, setting the spill 1974** threshold to a value such as 64KiB can greatly reduce the amount of 1975** I/O required to support statement rollback. 1976** The default value for this setting is controlled by the 1977** [SQLITE_STMTJRNL_SPILL] compile-time option. 1978** 1979** [[SQLITE_CONFIG_SORTERREF_SIZE]] 1980** <dt>SQLITE_CONFIG_SORTERREF_SIZE 1981** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter 1982** of type (int) - the new value of the sorter-reference size threshold. 1983** Usually, when SQLite uses an external sort to order records according 1984** to an ORDER BY clause, all fields required by the caller are present in the 1985** sorted records. However, if SQLite determines based on the declared type 1986** of a table column that its values are likely to be very large - larger 1987** than the configured sorter-reference size threshold - then a reference 1988** is stored in each sorted record and the required column values loaded 1989** from the database as records are returned in sorted order. The default 1990** value for this option is to never use this optimization. Specifying a 1991** negative value for this option restores the default behaviour. 1992** This option is only available if SQLite is compiled with the 1993** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option. 1994** 1995** [[SQLITE_CONFIG_MEMDB_MAXSIZE]] 1996** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE 1997** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter 1998** [sqlite3_int64] parameter which is the default maximum size for an in-memory 1999** database created using [sqlite3_deserialize()]. This default maximum 2000** size can be adjusted up or down for individual databases using the 2001** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control]. If this 2002** configuration setting is never used, then the default maximum is determined 2003** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option. If that 2004** compile-time option is not set, then the default maximum is 1073741824. 2005** </dl> 2006*/ 2007#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 2008#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 2009#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 2010#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 2011#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 2012#define SQLITE_CONFIG_SCRATCH 6 /* No longer used */ 2013#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 2014#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 2015#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 2016#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 2017#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 2018/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 2019#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 2020#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 2021#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 2022#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 2023#define SQLITE_CONFIG_URI 17 /* int */ 2024#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 2025#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 2026#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20 /* int */ 2027#define SQLITE_CONFIG_SQLLOG 21 /* xSqllog, void* */ 2028#define SQLITE_CONFIG_MMAP_SIZE 22 /* sqlite3_int64, sqlite3_int64 */ 2029#define SQLITE_CONFIG_WIN32_HEAPSIZE 23 /* int nByte */ 2030#define SQLITE_CONFIG_PCACHE_HDRSZ 24 /* int *psz */ 2031#define SQLITE_CONFIG_PMASZ 25 /* unsigned int szPma */ 2032#define SQLITE_CONFIG_STMTJRNL_SPILL 26 /* int nByte */ 2033#define SQLITE_CONFIG_SMALL_MALLOC 27 /* boolean */ 2034#define SQLITE_CONFIG_SORTERREF_SIZE 28 /* int nByte */ 2035#define SQLITE_CONFIG_MEMDB_MAXSIZE 29 /* sqlite3_int64 */ 2036 2037/* 2038** CAPI3REF: Database Connection Configuration Options 2039** 2040** These constants are the available integer configuration options that 2041** can be passed as the second argument to the [sqlite3_db_config()] interface. 2042** 2043** New configuration options may be added in future releases of SQLite. 2044** Existing configuration options might be discontinued. Applications 2045** should check the return code from [sqlite3_db_config()] to make sure that 2046** the call worked. ^The [sqlite3_db_config()] interface will return a 2047** non-zero [error code] if a discontinued or unsupported configuration option 2048** is invoked. 2049** 2050** <dl> 2051** [[SQLITE_DBCONFIG_LOOKASIDE]] 2052** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 2053** <dd> ^This option takes three additional arguments that determine the 2054** [lookaside memory allocator] configuration for the [database connection]. 2055** ^The first argument (the third parameter to [sqlite3_db_config()] is a 2056** pointer to a memory buffer to use for lookaside memory. 2057** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 2058** may be NULL in which case SQLite will allocate the 2059** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 2060** size of each lookaside buffer slot. ^The third argument is the number of 2061** slots. The size of the buffer in the first argument must be greater than 2062** or equal to the product of the second and third arguments. The buffer 2063** must be aligned to an 8-byte boundary. ^If the second argument to 2064** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 2065** rounded down to the next smaller multiple of 8. ^(The lookaside memory 2066** configuration for a database connection can only be changed when that 2067** connection is not currently using lookaside memory, or in other words 2068** when the "current value" returned by 2069** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 2070** Any attempt to change the lookaside memory configuration when lookaside 2071** memory is in use leaves the configuration unchanged and returns 2072** [SQLITE_BUSY].)^</dd> 2073** 2074** [[SQLITE_DBCONFIG_ENABLE_FKEY]] 2075** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 2076** <dd> ^This option is used to enable or disable the enforcement of 2077** [foreign key constraints]. There should be two additional arguments. 2078** The first argument is an integer which is 0 to disable FK enforcement, 2079** positive to enable FK enforcement or negative to leave FK enforcement 2080** unchanged. The second parameter is a pointer to an integer into which 2081** is written 0 or 1 to indicate whether FK enforcement is off or on 2082** following this call. The second parameter may be a NULL pointer, in 2083** which case the FK enforcement setting is not reported back. </dd> 2084** 2085** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]] 2086** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 2087** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 2088** There should be two additional arguments. 2089** The first argument is an integer which is 0 to disable triggers, 2090** positive to enable triggers or negative to leave the setting unchanged. 2091** The second parameter is a pointer to an integer into which 2092** is written 0 or 1 to indicate whether triggers are disabled or enabled 2093** following this call. The second parameter may be a NULL pointer, in 2094** which case the trigger setting is not reported back. </dd> 2095** 2096** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]] 2097** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt> 2098** <dd> ^This option is used to enable or disable the 2099** [fts3_tokenizer()] function which is part of the 2100** [FTS3] full-text search engine extension. 2101** There should be two additional arguments. 2102** The first argument is an integer which is 0 to disable fts3_tokenizer() or 2103** positive to enable fts3_tokenizer() or negative to leave the setting 2104** unchanged. 2105** The second parameter is a pointer to an integer into which 2106** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled 2107** following this call. The second parameter may be a NULL pointer, in 2108** which case the new setting is not reported back. </dd> 2109** 2110** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]] 2111** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt> 2112** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()] 2113** interface independently of the [load_extension()] SQL function. 2114** The [sqlite3_enable_load_extension()] API enables or disables both the 2115** C-API [sqlite3_load_extension()] and the SQL function [load_extension()]. 2116** There should be two additional arguments. 2117** When the first argument to this interface is 1, then only the C-API is 2118** enabled and the SQL function remains disabled. If the first argument to 2119** this interface is 0, then both the C-API and the SQL function are disabled. 2120** If the first argument is -1, then no changes are made to state of either the 2121** C-API or the SQL function. 2122** The second parameter is a pointer to an integer into which 2123** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface 2124** is disabled or enabled following this call. The second parameter may 2125** be a NULL pointer, in which case the new setting is not reported back. 2126** </dd> 2127** 2128** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt> 2129** <dd> ^This option is used to change the name of the "main" database 2130** schema. ^The sole argument is a pointer to a constant UTF8 string 2131** which will become the new schema name in place of "main". ^SQLite 2132** does not make a copy of the new main schema name string, so the application 2133** must ensure that the argument passed into this DBCONFIG option is unchanged 2134** until after the database connection closes. 2135** </dd> 2136** 2137** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]] 2138** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt> 2139** <dd> Usually, when a database in wal mode is closed or detached from a 2140** database handle, SQLite checks if this will mean that there are now no 2141** connections at all to the database. If so, it performs a checkpoint 2142** operation before closing the connection. This option may be used to 2143** override this behaviour. The first parameter passed to this operation 2144** is an integer - positive to disable checkpoints-on-close, or zero (the 2145** default) to enable them, and negative to leave the setting unchanged. 2146** The second parameter is a pointer to an integer 2147** into which is written 0 or 1 to indicate whether checkpoints-on-close 2148** have been disabled - 0 if they are not disabled, 1 if they are. 2149** </dd> 2150** 2151** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt> 2152** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates 2153** the [query planner stability guarantee] (QPSG). When the QPSG is active, 2154** a single SQL query statement will always use the same algorithm regardless 2155** of values of [bound parameters].)^ The QPSG disables some query optimizations 2156** that look at the values of bound parameters, which can make some queries 2157** slower. But the QPSG has the advantage of more predictable behavior. With 2158** the QPSG active, SQLite will always use the same query plan in the field as 2159** was used during testing in the lab. 2160** The first argument to this setting is an integer which is 0 to disable 2161** the QPSG, positive to enable QPSG, or negative to leave the setting 2162** unchanged. The second parameter is a pointer to an integer into which 2163** is written 0 or 1 to indicate whether the QPSG is disabled or enabled 2164** following this call. 2165** </dd> 2166** 2167** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt> 2168** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 2169** include output for any operations performed by trigger programs. This 2170** option is used to set or clear (the default) a flag that governs this 2171** behavior. The first parameter passed to this operation is an integer - 2172** positive to enable output for trigger programs, or zero to disable it, 2173** or negative to leave the setting unchanged. 2174** The second parameter is a pointer to an integer into which is written 2175** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 2176** it is not disabled, 1 if it is. 2177** </dd> 2178** 2179** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt> 2180** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run 2181** [VACUUM] in order to reset a database back to an empty database 2182** with no schema and no content. The following process works even for 2183** a badly corrupted database file: 2184** <ol> 2185** <li> If the database connection is newly opened, make sure it has read the 2186** database schema by preparing then discarding some query against the 2187** database, or calling sqlite3_table_column_metadata(), ignoring any 2188** errors. This step is only necessary if the application desires to keep 2189** the database in WAL mode after the reset if it was in WAL mode before 2190** the reset. 2191** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0); 2192** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0); 2193** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0); 2194** </ol> 2195** Because resetting a database is destructive and irreversible, the 2196** process requires the use of this obscure API and multiple steps to help 2197** ensure that it does not happen by accident. 2198** 2199** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt> 2200** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the 2201** "defensive" flag for a database connection. When the defensive 2202** flag is enabled, language features that allow ordinary SQL to 2203** deliberately corrupt the database file are disabled. The disabled 2204** features include but are not limited to the following: 2205** <ul> 2206** <li> The [PRAGMA writable_schema=ON] statement. 2207** <li> The [PRAGMA journal_mode=OFF] statement. 2208** <li> Writes to the [sqlite_dbpage] virtual table. 2209** <li> Direct writes to [shadow tables]. 2210** </ul> 2211** </dd> 2212** 2213** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt> 2214** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the 2215** "writable_schema" flag. This has the same effect and is logically equivalent 2216** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF]. 2217** The first argument to this setting is an integer which is 0 to disable 2218** the writable_schema, positive to enable writable_schema, or negative to 2219** leave the setting unchanged. The second parameter is a pointer to an 2220** integer into which is written 0 or 1 to indicate whether the writable_schema 2221** is enabled or disabled following this call. 2222** </dd> 2223** 2224** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]] 2225** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt> 2226** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates 2227** the legacy behavior of the [ALTER TABLE RENAME] command such it 2228** behaves as it did prior to [version 3.24.0] (2018-06-04). See the 2229** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for 2230** additional information. This feature can also be turned on and off 2231** using the [PRAGMA legacy_alter_table] statement. 2232** </dd> 2233** 2234** [[SQLITE_DBCONFIG_DQS_DML]] 2235** <dt>SQLITE_DBCONFIG_DQS_DML</td> 2236** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates 2237** the legacy [double-quoted string literal] misfeature for DML statement 2238** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The 2239** default value of this setting is determined by the [-DSQLITE_DQS] 2240** compile-time option. 2241** </dd> 2242** 2243** [[SQLITE_DBCONFIG_DQS_DDL]] 2244** <dt>SQLITE_DBCONFIG_DQS_DDL</td> 2245** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates 2246** the legacy [double-quoted string literal] misfeature for DDL statements, 2247** such as CREATE TABLE and CREATE INDEX. The 2248** default value of this setting is determined by the [-DSQLITE_DQS] 2249** compile-time option. 2250** </dd> 2251** </dl> 2252*/ 2253#define SQLITE_DBCONFIG_MAINDBNAME 1000 /* const char* */ 2254#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 2255#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 2256#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 2257#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */ 2258#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */ 2259#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE 1006 /* int int* */ 2260#define SQLITE_DBCONFIG_ENABLE_QPSG 1007 /* int int* */ 2261#define SQLITE_DBCONFIG_TRIGGER_EQP 1008 /* int int* */ 2262#define SQLITE_DBCONFIG_RESET_DATABASE 1009 /* int int* */ 2263#define SQLITE_DBCONFIG_DEFENSIVE 1010 /* int int* */ 2264#define SQLITE_DBCONFIG_WRITABLE_SCHEMA 1011 /* int int* */ 2265#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE 1012 /* int int* */ 2266#define SQLITE_DBCONFIG_DQS_DML 1013 /* int int* */ 2267#define SQLITE_DBCONFIG_DQS_DDL 1014 /* int int* */ 2268#define SQLITE_DBCONFIG_MAX 1014 /* Largest DBCONFIG */ 2269 2270/* 2271** CAPI3REF: Enable Or Disable Extended Result Codes 2272** METHOD: sqlite3 2273** 2274** ^The sqlite3_extended_result_codes() routine enables or disables the 2275** [extended result codes] feature of SQLite. ^The extended result 2276** codes are disabled by default for historical compatibility. 2277*/ 2278int sqlite3_extended_result_codes(sqlite3*, int onoff); 2279 2280/* 2281** CAPI3REF: Last Insert Rowid 2282** METHOD: sqlite3 2283** 2284** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables) 2285** has a unique 64-bit signed 2286** integer key called the [ROWID | "rowid"]. ^The rowid is always available 2287** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 2288** names are not also used by explicitly declared columns. ^If 2289** the table has a column of type [INTEGER PRIMARY KEY] then that column 2290** is another alias for the rowid. 2291** 2292** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of 2293** the most recent successful [INSERT] into a rowid table or [virtual table] 2294** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not 2295** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 2296** on the database connection D, then sqlite3_last_insert_rowid(D) returns 2297** zero. 2298** 2299** As well as being set automatically as rows are inserted into database 2300** tables, the value returned by this function may be set explicitly by 2301** [sqlite3_set_last_insert_rowid()] 2302** 2303** Some virtual table implementations may INSERT rows into rowid tables as 2304** part of committing a transaction (e.g. to flush data accumulated in memory 2305** to disk). In this case subsequent calls to this function return the rowid 2306** associated with these internal INSERT operations, which leads to 2307** unintuitive results. Virtual table implementations that do write to rowid 2308** tables in this way can avoid this problem by restoring the original 2309** rowid value using [sqlite3_set_last_insert_rowid()] before returning 2310** control to the user. 2311** 2312** ^(If an [INSERT] occurs within a trigger then this routine will 2313** return the [rowid] of the inserted row as long as the trigger is 2314** running. Once the trigger program ends, the value returned 2315** by this routine reverts to what it was before the trigger was fired.)^ 2316** 2317** ^An [INSERT] that fails due to a constraint violation is not a 2318** successful [INSERT] and does not change the value returned by this 2319** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 2320** and INSERT OR ABORT make no changes to the return value of this 2321** routine when their insertion fails. ^(When INSERT OR REPLACE 2322** encounters a constraint violation, it does not fail. The 2323** INSERT continues to completion after deleting rows that caused 2324** the constraint problem so INSERT OR REPLACE will always change 2325** the return value of this interface.)^ 2326** 2327** ^For the purposes of this routine, an [INSERT] is considered to 2328** be successful even if it is subsequently rolled back. 2329** 2330** This function is accessible to SQL statements via the 2331** [last_insert_rowid() SQL function]. 2332** 2333** If a separate thread performs a new [INSERT] on the same 2334** database connection while the [sqlite3_last_insert_rowid()] 2335** function is running and thus changes the last insert [rowid], 2336** then the value returned by [sqlite3_last_insert_rowid()] is 2337** unpredictable and might not equal either the old or the new 2338** last insert [rowid]. 2339*/ 2340sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 2341 2342/* 2343** CAPI3REF: Set the Last Insert Rowid value. 2344** METHOD: sqlite3 2345** 2346** The sqlite3_set_last_insert_rowid(D, R) method allows the application to 2347** set the value returned by calling sqlite3_last_insert_rowid(D) to R 2348** without inserting a row into the database. 2349*/ 2350void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64); 2351 2352/* 2353** CAPI3REF: Count The Number Of Rows Modified 2354** METHOD: sqlite3 2355** 2356** ^This function returns the number of rows modified, inserted or 2357** deleted by the most recently completed INSERT, UPDATE or DELETE 2358** statement on the database connection specified by the only parameter. 2359** ^Executing any other type of SQL statement does not modify the value 2360** returned by this function. 2361** 2362** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are 2363** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 2364** [foreign key actions] or [REPLACE] constraint resolution are not counted. 2365** 2366** Changes to a view that are intercepted by 2367** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 2368** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 2369** DELETE statement run on a view is always zero. Only changes made to real 2370** tables are counted. 2371** 2372** Things are more complicated if the sqlite3_changes() function is 2373** executed while a trigger program is running. This may happen if the 2374** program uses the [changes() SQL function], or if some other callback 2375** function invokes sqlite3_changes() directly. Essentially: 2376** 2377** <ul> 2378** <li> ^(Before entering a trigger program the value returned by 2379** sqlite3_changes() function is saved. After the trigger program 2380** has finished, the original value is restored.)^ 2381** 2382** <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 2383** statement sets the value returned by sqlite3_changes() 2384** upon completion as normal. Of course, this value will not include 2385** any changes performed by sub-triggers, as the sqlite3_changes() 2386** value will be saved and restored after each sub-trigger has run.)^ 2387** </ul> 2388** 2389** ^This means that if the changes() SQL function (or similar) is used 2390** by the first INSERT, UPDATE or DELETE statement within a trigger, it 2391** returns the value as set when the calling statement began executing. 2392** ^If it is used by the second or subsequent such statement within a trigger 2393** program, the value returned reflects the number of rows modified by the 2394** previous INSERT, UPDATE or DELETE statement within the same trigger. 2395** 2396** If a separate thread makes changes on the same database connection 2397** while [sqlite3_changes()] is running then the value returned 2398** is unpredictable and not meaningful. 2399** 2400** See also: 2401** <ul> 2402** <li> the [sqlite3_total_changes()] interface 2403** <li> the [count_changes pragma] 2404** <li> the [changes() SQL function] 2405** <li> the [data_version pragma] 2406** </ul> 2407*/ 2408int sqlite3_changes(sqlite3*); 2409 2410/* 2411** CAPI3REF: Total Number Of Rows Modified 2412** METHOD: sqlite3 2413** 2414** ^This function returns the total number of rows inserted, modified or 2415** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed 2416** since the database connection was opened, including those executed as 2417** part of trigger programs. ^Executing any other type of SQL statement 2418** does not affect the value returned by sqlite3_total_changes(). 2419** 2420** ^Changes made as part of [foreign key actions] are included in the 2421** count, but those made as part of REPLACE constraint resolution are 2422** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 2423** are not counted. 2424** 2425** The [sqlite3_total_changes(D)] interface only reports the number 2426** of rows that changed due to SQL statement run against database 2427** connection D. Any changes by other database connections are ignored. 2428** To detect changes against a database file from other database 2429** connections use the [PRAGMA data_version] command or the 2430** [SQLITE_FCNTL_DATA_VERSION] [file control]. 2431** 2432** If a separate thread makes changes on the same database connection 2433** while [sqlite3_total_changes()] is running then the value 2434** returned is unpredictable and not meaningful. 2435** 2436** See also: 2437** <ul> 2438** <li> the [sqlite3_changes()] interface 2439** <li> the [count_changes pragma] 2440** <li> the [changes() SQL function] 2441** <li> the [data_version pragma] 2442** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control] 2443** </ul> 2444*/ 2445int sqlite3_total_changes(sqlite3*); 2446 2447/* 2448** CAPI3REF: Interrupt A Long-Running Query 2449** METHOD: sqlite3 2450** 2451** ^This function causes any pending database operation to abort and 2452** return at its earliest opportunity. This routine is typically 2453** called in response to a user action such as pressing "Cancel" 2454** or Ctrl-C where the user wants a long query operation to halt 2455** immediately. 2456** 2457** ^It is safe to call this routine from a thread different from the 2458** thread that is currently running the database operation. But it 2459** is not safe to call this routine with a [database connection] that 2460** is closed or might close before sqlite3_interrupt() returns. 2461** 2462** ^If an SQL operation is very nearly finished at the time when 2463** sqlite3_interrupt() is called, then it might not have an opportunity 2464** to be interrupted and might continue to completion. 2465** 2466** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 2467** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 2468** that is inside an explicit transaction, then the entire transaction 2469** will be rolled back automatically. 2470** 2471** ^The sqlite3_interrupt(D) call is in effect until all currently running 2472** SQL statements on [database connection] D complete. ^Any new SQL statements 2473** that are started after the sqlite3_interrupt() call and before the 2474** running statements reaches zero are interrupted as if they had been 2475** running prior to the sqlite3_interrupt() call. ^New SQL statements 2476** that are started after the running statement count reaches zero are 2477** not effected by the sqlite3_interrupt(). 2478** ^A call to sqlite3_interrupt(D) that occurs when there are no running 2479** SQL statements is a no-op and has no effect on SQL statements 2480** that are started after the sqlite3_interrupt() call returns. 2481*/ 2482void sqlite3_interrupt(sqlite3*); 2483 2484/* 2485** CAPI3REF: Determine If An SQL Statement Is Complete 2486** 2487** These routines are useful during command-line input to determine if the 2488** currently entered text seems to form a complete SQL statement or 2489** if additional input is needed before sending the text into 2490** SQLite for parsing. ^These routines return 1 if the input string 2491** appears to be a complete SQL statement. ^A statement is judged to be 2492** complete if it ends with a semicolon token and is not a prefix of a 2493** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 2494** string literals or quoted identifier names or comments are not 2495** independent tokens (they are part of the token in which they are 2496** embedded) and thus do not count as a statement terminator. ^Whitespace 2497** and comments that follow the final semicolon are ignored. 2498** 2499** ^These routines return 0 if the statement is incomplete. ^If a 2500** memory allocation fails, then SQLITE_NOMEM is returned. 2501** 2502** ^These routines do not parse the SQL statements thus 2503** will not detect syntactically incorrect SQL. 2504** 2505** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 2506** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 2507** automatically by sqlite3_complete16(). If that initialization fails, 2508** then the return value from sqlite3_complete16() will be non-zero 2509** regardless of whether or not the input SQL is complete.)^ 2510** 2511** The input to [sqlite3_complete()] must be a zero-terminated 2512** UTF-8 string. 2513** 2514** The input to [sqlite3_complete16()] must be a zero-terminated 2515** UTF-16 string in native byte order. 2516*/ 2517int sqlite3_complete(const char *sql); 2518int sqlite3_complete16(const void *sql); 2519 2520/* 2521** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 2522** KEYWORDS: {busy-handler callback} {busy handler} 2523** METHOD: sqlite3 2524** 2525** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X 2526** that might be invoked with argument P whenever 2527** an attempt is made to access a database table associated with 2528** [database connection] D when another thread 2529** or process has the table locked. 2530** The sqlite3_busy_handler() interface is used to implement 2531** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout]. 2532** 2533** ^If the busy callback is NULL, then [SQLITE_BUSY] 2534** is returned immediately upon encountering the lock. ^If the busy callback 2535** is not NULL, then the callback might be invoked with two arguments. 2536** 2537** ^The first argument to the busy handler is a copy of the void* pointer which 2538** is the third argument to sqlite3_busy_handler(). ^The second argument to 2539** the busy handler callback is the number of times that the busy handler has 2540** been invoked previously for the same locking event. ^If the 2541** busy callback returns 0, then no additional attempts are made to 2542** access the database and [SQLITE_BUSY] is returned 2543** to the application. 2544** ^If the callback returns non-zero, then another attempt 2545** is made to access the database and the cycle repeats. 2546** 2547** The presence of a busy handler does not guarantee that it will be invoked 2548** when there is lock contention. ^If SQLite determines that invoking the busy 2549** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 2550** to the application instead of invoking the 2551** busy handler. 2552** Consider a scenario where one process is holding a read lock that 2553** it is trying to promote to a reserved lock and 2554** a second process is holding a reserved lock that it is trying 2555** to promote to an exclusive lock. The first process cannot proceed 2556** because it is blocked by the second and the second process cannot 2557** proceed because it is blocked by the first. If both processes 2558** invoke the busy handlers, neither will make any progress. Therefore, 2559** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 2560** will induce the first process to release its read lock and allow 2561** the second process to proceed. 2562** 2563** ^The default busy callback is NULL. 2564** 2565** ^(There can only be a single busy handler defined for each 2566** [database connection]. Setting a new busy handler clears any 2567** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 2568** or evaluating [PRAGMA busy_timeout=N] will change the 2569** busy handler and thus clear any previously set busy handler. 2570** 2571** The busy callback should not take any actions which modify the 2572** database connection that invoked the busy handler. In other words, 2573** the busy handler is not reentrant. Any such actions 2574** result in undefined behavior. 2575** 2576** A busy handler must not close the database connection 2577** or [prepared statement] that invoked the busy handler. 2578*/ 2579int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*); 2580 2581/* 2582** CAPI3REF: Set A Busy Timeout 2583** METHOD: sqlite3 2584** 2585** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 2586** for a specified amount of time when a table is locked. ^The handler 2587** will sleep multiple times until at least "ms" milliseconds of sleeping 2588** have accumulated. ^After at least "ms" milliseconds of sleeping, 2589** the handler returns 0 which causes [sqlite3_step()] to return 2590** [SQLITE_BUSY]. 2591** 2592** ^Calling this routine with an argument less than or equal to zero 2593** turns off all busy handlers. 2594** 2595** ^(There can only be a single busy handler for a particular 2596** [database connection] at any given moment. If another busy handler 2597** was defined (using [sqlite3_busy_handler()]) prior to calling 2598** this routine, that other busy handler is cleared.)^ 2599** 2600** See also: [PRAGMA busy_timeout] 2601*/ 2602int sqlite3_busy_timeout(sqlite3*, int ms); 2603 2604/* 2605** CAPI3REF: Convenience Routines For Running Queries 2606** METHOD: sqlite3 2607** 2608** This is a legacy interface that is preserved for backwards compatibility. 2609** Use of this interface is not recommended. 2610** 2611** Definition: A <b>result table</b> is memory data structure created by the 2612** [sqlite3_get_table()] interface. A result table records the 2613** complete query results from one or more queries. 2614** 2615** The table conceptually has a number of rows and columns. But 2616** these numbers are not part of the result table itself. These 2617** numbers are obtained separately. Let N be the number of rows 2618** and M be the number of columns. 2619** 2620** A result table is an array of pointers to zero-terminated UTF-8 strings. 2621** There are (N+1)*M elements in the array. The first M pointers point 2622** to zero-terminated strings that contain the names of the columns. 2623** The remaining entries all point to query results. NULL values result 2624** in NULL pointers. All other values are in their UTF-8 zero-terminated 2625** string representation as returned by [sqlite3_column_text()]. 2626** 2627** A result table might consist of one or more memory allocations. 2628** It is not safe to pass a result table directly to [sqlite3_free()]. 2629** A result table should be deallocated using [sqlite3_free_table()]. 2630** 2631** ^(As an example of the result table format, suppose a query result 2632** is as follows: 2633** 2634** <blockquote><pre> 2635** Name | Age 2636** ----------------------- 2637** Alice | 43 2638** Bob | 28 2639** Cindy | 21 2640** </pre></blockquote> 2641** 2642** There are two column (M==2) and three rows (N==3). Thus the 2643** result table has 8 entries. Suppose the result table is stored 2644** in an array names azResult. Then azResult holds this content: 2645** 2646** <blockquote><pre> 2647** azResult[0] = "Name"; 2648** azResult[1] = "Age"; 2649** azResult[2] = "Alice"; 2650** azResult[3] = "43"; 2651** azResult[4] = "Bob"; 2652** azResult[5] = "28"; 2653** azResult[6] = "Cindy"; 2654** azResult[7] = "21"; 2655** </pre></blockquote>)^ 2656** 2657** ^The sqlite3_get_table() function evaluates one or more 2658** semicolon-separated SQL statements in the zero-terminated UTF-8 2659** string of its 2nd parameter and returns a result table to the 2660** pointer given in its 3rd parameter. 2661** 2662** After the application has finished with the result from sqlite3_get_table(), 2663** it must pass the result table pointer to sqlite3_free_table() in order to 2664** release the memory that was malloced. Because of the way the 2665** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 2666** function must not try to call [sqlite3_free()] directly. Only 2667** [sqlite3_free_table()] is able to release the memory properly and safely. 2668** 2669** The sqlite3_get_table() interface is implemented as a wrapper around 2670** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2671** to any internal data structures of SQLite. It uses only the public 2672** interface defined here. As a consequence, errors that occur in the 2673** wrapper layer outside of the internal [sqlite3_exec()] call are not 2674** reflected in subsequent calls to [sqlite3_errcode()] or 2675** [sqlite3_errmsg()]. 2676*/ 2677int sqlite3_get_table( 2678 sqlite3 *db, /* An open database */ 2679 const char *zSql, /* SQL to be evaluated */ 2680 char ***pazResult, /* Results of the query */ 2681 int *pnRow, /* Number of result rows written here */ 2682 int *pnColumn, /* Number of result columns written here */ 2683 char **pzErrmsg /* Error msg written here */ 2684); 2685void sqlite3_free_table(char **result); 2686 2687/* 2688** CAPI3REF: Formatted String Printing Functions 2689** 2690** These routines are work-alikes of the "printf()" family of functions 2691** from the standard C library. 2692** These routines understand most of the common formatting options from 2693** the standard library printf() 2694** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]). 2695** See the [built-in printf()] documentation for details. 2696** 2697** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2698** results into memory obtained from [sqlite3_malloc64()]. 2699** The strings returned by these two routines should be 2700** released by [sqlite3_free()]. ^Both routines return a 2701** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough 2702** memory to hold the resulting string. 2703** 2704** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2705** the standard C library. The result is written into the 2706** buffer supplied as the second parameter whose size is given by 2707** the first parameter. Note that the order of the 2708** first two parameters is reversed from snprintf().)^ This is an 2709** historical accident that cannot be fixed without breaking 2710** backwards compatibility. ^(Note also that sqlite3_snprintf() 2711** returns a pointer to its buffer instead of the number of 2712** characters actually written into the buffer.)^ We admit that 2713** the number of characters written would be a more useful return 2714** value but we cannot change the implementation of sqlite3_snprintf() 2715** now without breaking compatibility. 2716** 2717** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2718** guarantees that the buffer is always zero-terminated. ^The first 2719** parameter "n" is the total size of the buffer, including space for 2720** the zero terminator. So the longest string that can be completely 2721** written will be n-1 characters. 2722** 2723** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2724** 2725** See also: [built-in printf()], [printf() SQL function] 2726*/ 2727char *sqlite3_mprintf(const char*,...); 2728char *sqlite3_vmprintf(const char*, va_list); 2729char *sqlite3_snprintf(int,char*,const char*, ...); 2730char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2731 2732/* 2733** CAPI3REF: Memory Allocation Subsystem 2734** 2735** The SQLite core uses these three routines for all of its own 2736** internal memory allocation needs. "Core" in the previous sentence 2737** does not include operating-system specific VFS implementation. The 2738** Windows VFS uses native malloc() and free() for some operations. 2739** 2740** ^The sqlite3_malloc() routine returns a pointer to a block 2741** of memory at least N bytes in length, where N is the parameter. 2742** ^If sqlite3_malloc() is unable to obtain sufficient free 2743** memory, it returns a NULL pointer. ^If the parameter N to 2744** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2745** a NULL pointer. 2746** 2747** ^The sqlite3_malloc64(N) routine works just like 2748** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead 2749** of a signed 32-bit integer. 2750** 2751** ^Calling sqlite3_free() with a pointer previously returned 2752** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2753** that it might be reused. ^The sqlite3_free() routine is 2754** a no-op if is called with a NULL pointer. Passing a NULL pointer 2755** to sqlite3_free() is harmless. After being freed, memory 2756** should neither be read nor written. Even reading previously freed 2757** memory might result in a segmentation fault or other severe error. 2758** Memory corruption, a segmentation fault, or other severe error 2759** might result if sqlite3_free() is called with a non-NULL pointer that 2760** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2761** 2762** ^The sqlite3_realloc(X,N) interface attempts to resize a 2763** prior memory allocation X to be at least N bytes. 2764** ^If the X parameter to sqlite3_realloc(X,N) 2765** is a NULL pointer then its behavior is identical to calling 2766** sqlite3_malloc(N). 2767** ^If the N parameter to sqlite3_realloc(X,N) is zero or 2768** negative then the behavior is exactly the same as calling 2769** sqlite3_free(X). 2770** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation 2771** of at least N bytes in size or NULL if insufficient memory is available. 2772** ^If M is the size of the prior allocation, then min(N,M) bytes 2773** of the prior allocation are copied into the beginning of buffer returned 2774** by sqlite3_realloc(X,N) and the prior allocation is freed. 2775** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the 2776** prior allocation is not freed. 2777** 2778** ^The sqlite3_realloc64(X,N) interfaces works the same as 2779** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead 2780** of a 32-bit signed integer. 2781** 2782** ^If X is a memory allocation previously obtained from sqlite3_malloc(), 2783** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then 2784** sqlite3_msize(X) returns the size of that memory allocation in bytes. 2785** ^The value returned by sqlite3_msize(X) might be larger than the number 2786** of bytes requested when X was allocated. ^If X is a NULL pointer then 2787** sqlite3_msize(X) returns zero. If X points to something that is not 2788** the beginning of memory allocation, or if it points to a formerly 2789** valid memory allocation that has now been freed, then the behavior 2790** of sqlite3_msize(X) is undefined and possibly harmful. 2791** 2792** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(), 2793** sqlite3_malloc64(), and sqlite3_realloc64() 2794** is always aligned to at least an 8 byte boundary, or to a 2795** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2796** option is used. 2797** 2798** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2799** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2800** implementation of these routines to be omitted. That capability 2801** is no longer provided. Only built-in memory allocators can be used. 2802** 2803** Prior to SQLite version 3.7.10, the Windows OS interface layer called 2804** the system malloc() and free() directly when converting 2805** filenames between the UTF-8 encoding used by SQLite 2806** and whatever filename encoding is used by the particular Windows 2807** installation. Memory allocation errors were detected, but 2808** they were reported back as [SQLITE_CANTOPEN] or 2809** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2810** 2811** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2812** must be either NULL or else pointers obtained from a prior 2813** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2814** not yet been released. 2815** 2816** The application must not read or write any part of 2817** a block of memory after it has been released using 2818** [sqlite3_free()] or [sqlite3_realloc()]. 2819*/ 2820void *sqlite3_malloc(int); 2821void *sqlite3_malloc64(sqlite3_uint64); 2822void *sqlite3_realloc(void*, int); 2823void *sqlite3_realloc64(void*, sqlite3_uint64); 2824void sqlite3_free(void*); 2825sqlite3_uint64 sqlite3_msize(void*); 2826 2827/* 2828** CAPI3REF: Memory Allocator Statistics 2829** 2830** SQLite provides these two interfaces for reporting on the status 2831** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2832** routines, which form the built-in memory allocation subsystem. 2833** 2834** ^The [sqlite3_memory_used()] routine returns the number of bytes 2835** of memory currently outstanding (malloced but not freed). 2836** ^The [sqlite3_memory_highwater()] routine returns the maximum 2837** value of [sqlite3_memory_used()] since the high-water mark 2838** was last reset. ^The values returned by [sqlite3_memory_used()] and 2839** [sqlite3_memory_highwater()] include any overhead 2840** added by SQLite in its implementation of [sqlite3_malloc()], 2841** but not overhead added by the any underlying system library 2842** routines that [sqlite3_malloc()] may call. 2843** 2844** ^The memory high-water mark is reset to the current value of 2845** [sqlite3_memory_used()] if and only if the parameter to 2846** [sqlite3_memory_highwater()] is true. ^The value returned 2847** by [sqlite3_memory_highwater(1)] is the high-water mark 2848** prior to the reset. 2849*/ 2850sqlite3_int64 sqlite3_memory_used(void); 2851sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2852 2853/* 2854** CAPI3REF: Pseudo-Random Number Generator 2855** 2856** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2857** select random [ROWID | ROWIDs] when inserting new records into a table that 2858** already uses the largest possible [ROWID]. The PRNG is also used for 2859** the build-in random() and randomblob() SQL functions. This interface allows 2860** applications to access the same PRNG for other purposes. 2861** 2862** ^A call to this routine stores N bytes of randomness into buffer P. 2863** ^The P parameter can be a NULL pointer. 2864** 2865** ^If this routine has not been previously called or if the previous 2866** call had N less than one or a NULL pointer for P, then the PRNG is 2867** seeded using randomness obtained from the xRandomness method of 2868** the default [sqlite3_vfs] object. 2869** ^If the previous call to this routine had an N of 1 or more and a 2870** non-NULL P then the pseudo-randomness is generated 2871** internally and without recourse to the [sqlite3_vfs] xRandomness 2872** method. 2873*/ 2874void sqlite3_randomness(int N, void *P); 2875 2876/* 2877** CAPI3REF: Compile-Time Authorization Callbacks 2878** METHOD: sqlite3 2879** KEYWORDS: {authorizer callback} 2880** 2881** ^This routine registers an authorizer callback with a particular 2882** [database connection], supplied in the first argument. 2883** ^The authorizer callback is invoked as SQL statements are being compiled 2884** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2885** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()], 2886** and [sqlite3_prepare16_v3()]. ^At various 2887** points during the compilation process, as logic is being created 2888** to perform various actions, the authorizer callback is invoked to 2889** see if those actions are allowed. ^The authorizer callback should 2890** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2891** specific action but allow the SQL statement to continue to be 2892** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2893** rejected with an error. ^If the authorizer callback returns 2894** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2895** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2896** the authorizer will fail with an error message. 2897** 2898** When the callback returns [SQLITE_OK], that means the operation 2899** requested is ok. ^When the callback returns [SQLITE_DENY], the 2900** [sqlite3_prepare_v2()] or equivalent call that triggered the 2901** authorizer will fail with an error message explaining that 2902** access is denied. 2903** 2904** ^The first parameter to the authorizer callback is a copy of the third 2905** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2906** to the callback is an integer [SQLITE_COPY | action code] that specifies 2907** the particular action to be authorized. ^The third through sixth parameters 2908** to the callback are either NULL pointers or zero-terminated strings 2909** that contain additional details about the action to be authorized. 2910** Applications must always be prepared to encounter a NULL pointer in any 2911** of the third through the sixth parameters of the authorization callback. 2912** 2913** ^If the action code is [SQLITE_READ] 2914** and the callback returns [SQLITE_IGNORE] then the 2915** [prepared statement] statement is constructed to substitute 2916** a NULL value in place of the table column that would have 2917** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2918** return can be used to deny an untrusted user access to individual 2919** columns of a table. 2920** ^When a table is referenced by a [SELECT] but no column values are 2921** extracted from that table (for example in a query like 2922** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback 2923** is invoked once for that table with a column name that is an empty string. 2924** ^If the action code is [SQLITE_DELETE] and the callback returns 2925** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2926** [truncate optimization] is disabled and all rows are deleted individually. 2927** 2928** An authorizer is used when [sqlite3_prepare | preparing] 2929** SQL statements from an untrusted source, to ensure that the SQL statements 2930** do not try to access data they are not allowed to see, or that they do not 2931** try to execute malicious statements that damage the database. For 2932** example, an application may allow a user to enter arbitrary 2933** SQL queries for evaluation by a database. But the application does 2934** not want the user to be able to make arbitrary changes to the 2935** database. An authorizer could then be put in place while the 2936** user-entered SQL is being [sqlite3_prepare | prepared] that 2937** disallows everything except [SELECT] statements. 2938** 2939** Applications that need to process SQL from untrusted sources 2940** might also consider lowering resource limits using [sqlite3_limit()] 2941** and limiting database size using the [max_page_count] [PRAGMA] 2942** in addition to using an authorizer. 2943** 2944** ^(Only a single authorizer can be in place on a database connection 2945** at a time. Each call to sqlite3_set_authorizer overrides the 2946** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2947** The authorizer is disabled by default. 2948** 2949** The authorizer callback must not do anything that will modify 2950** the database connection that invoked the authorizer callback. 2951** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2952** database connections for the meaning of "modify" in this paragraph. 2953** 2954** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2955** statement might be re-prepared during [sqlite3_step()] due to a 2956** schema change. Hence, the application should ensure that the 2957** correct authorizer callback remains in place during the [sqlite3_step()]. 2958** 2959** ^Note that the authorizer callback is invoked only during 2960** [sqlite3_prepare()] or its variants. Authorization is not 2961** performed during statement evaluation in [sqlite3_step()], unless 2962** as stated in the previous paragraph, sqlite3_step() invokes 2963** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2964*/ 2965int sqlite3_set_authorizer( 2966 sqlite3*, 2967 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2968 void *pUserData 2969); 2970 2971/* 2972** CAPI3REF: Authorizer Return Codes 2973** 2974** The [sqlite3_set_authorizer | authorizer callback function] must 2975** return either [SQLITE_OK] or one of these two constants in order 2976** to signal SQLite whether or not the action is permitted. See the 2977** [sqlite3_set_authorizer | authorizer documentation] for additional 2978** information. 2979** 2980** Note that SQLITE_IGNORE is also used as a [conflict resolution mode] 2981** returned from the [sqlite3_vtab_on_conflict()] interface. 2982*/ 2983#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2984#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2985 2986/* 2987** CAPI3REF: Authorizer Action Codes 2988** 2989** The [sqlite3_set_authorizer()] interface registers a callback function 2990** that is invoked to authorize certain SQL statement actions. The 2991** second parameter to the callback is an integer code that specifies 2992** what action is being authorized. These are the integer action codes that 2993** the authorizer callback may be passed. 2994** 2995** These action code values signify what kind of operation is to be 2996** authorized. The 3rd and 4th parameters to the authorization 2997** callback function will be parameters or NULL depending on which of these 2998** codes is used as the second parameter. ^(The 5th parameter to the 2999** authorizer callback is the name of the database ("main", "temp", 3000** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 3001** is the name of the inner-most trigger or view that is responsible for 3002** the access attempt or NULL if this access attempt is directly from 3003** top-level SQL code. 3004*/ 3005/******************************************* 3rd ************ 4th ***********/ 3006#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 3007#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 3008#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 3009#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 3010#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 3011#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 3012#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 3013#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 3014#define SQLITE_DELETE 9 /* Table Name NULL */ 3015#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 3016#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 3017#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 3018#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 3019#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 3020#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 3021#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 3022#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 3023#define SQLITE_INSERT 18 /* Table Name NULL */ 3024#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 3025#define SQLITE_READ 20 /* Table Name Column Name */ 3026#define SQLITE_SELECT 21 /* NULL NULL */ 3027#define SQLITE_TRANSACTION 22 /* Operation NULL */ 3028#define SQLITE_UPDATE 23 /* Table Name Column Name */ 3029#define SQLITE_ATTACH 24 /* Filename NULL */ 3030#define SQLITE_DETACH 25 /* Database Name NULL */ 3031#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 3032#define SQLITE_REINDEX 27 /* Index Name NULL */ 3033#define SQLITE_ANALYZE 28 /* Table Name NULL */ 3034#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 3035#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 3036#define SQLITE_FUNCTION 31 /* NULL Function Name */ 3037#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 3038#define SQLITE_COPY 0 /* No longer used */ 3039#define SQLITE_RECURSIVE 33 /* NULL NULL */ 3040 3041/* 3042** CAPI3REF: Tracing And Profiling Functions 3043** METHOD: sqlite3 3044** 3045** These routines are deprecated. Use the [sqlite3_trace_v2()] interface 3046** instead of the routines described here. 3047** 3048** These routines register callback functions that can be used for 3049** tracing and profiling the execution of SQL statements. 3050** 3051** ^The callback function registered by sqlite3_trace() is invoked at 3052** various times when an SQL statement is being run by [sqlite3_step()]. 3053** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 3054** SQL statement text as the statement first begins executing. 3055** ^(Additional sqlite3_trace() callbacks might occur 3056** as each triggered subprogram is entered. The callbacks for triggers 3057** contain a UTF-8 SQL comment that identifies the trigger.)^ 3058** 3059** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit 3060** the length of [bound parameter] expansion in the output of sqlite3_trace(). 3061** 3062** ^The callback function registered by sqlite3_profile() is invoked 3063** as each SQL statement finishes. ^The profile callback contains 3064** the original statement text and an estimate of wall-clock time 3065** of how long that statement took to run. ^The profile callback 3066** time is in units of nanoseconds, however the current implementation 3067** is only capable of millisecond resolution so the six least significant 3068** digits in the time are meaningless. Future versions of SQLite 3069** might provide greater resolution on the profiler callback. Invoking 3070** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the 3071** profile callback. 3072*/ 3073SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*, 3074 void(*xTrace)(void*,const char*), void*); 3075SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*, 3076 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 3077 3078/* 3079** CAPI3REF: SQL Trace Event Codes 3080** KEYWORDS: SQLITE_TRACE 3081** 3082** These constants identify classes of events that can be monitored 3083** using the [sqlite3_trace_v2()] tracing logic. The M argument 3084** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of 3085** the following constants. ^The first argument to the trace callback 3086** is one of the following constants. 3087** 3088** New tracing constants may be added in future releases. 3089** 3090** ^A trace callback has four arguments: xCallback(T,C,P,X). 3091** ^The T argument is one of the integer type codes above. 3092** ^The C argument is a copy of the context pointer passed in as the 3093** fourth argument to [sqlite3_trace_v2()]. 3094** The P and X arguments are pointers whose meanings depend on T. 3095** 3096** <dl> 3097** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt> 3098** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement 3099** first begins running and possibly at other times during the 3100** execution of the prepared statement, such as at the start of each 3101** trigger subprogram. ^The P argument is a pointer to the 3102** [prepared statement]. ^The X argument is a pointer to a string which 3103** is the unexpanded SQL text of the prepared statement or an SQL comment 3104** that indicates the invocation of a trigger. ^The callback can compute 3105** the same text that would have been returned by the legacy [sqlite3_trace()] 3106** interface by using the X argument when X begins with "--" and invoking 3107** [sqlite3_expanded_sql(P)] otherwise. 3108** 3109** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt> 3110** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same 3111** information as is provided by the [sqlite3_profile()] callback. 3112** ^The P argument is a pointer to the [prepared statement] and the 3113** X argument points to a 64-bit integer which is the estimated of 3114** the number of nanosecond that the prepared statement took to run. 3115** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes. 3116** 3117** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt> 3118** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared 3119** statement generates a single row of result. 3120** ^The P argument is a pointer to the [prepared statement] and the 3121** X argument is unused. 3122** 3123** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt> 3124** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database 3125** connection closes. 3126** ^The P argument is a pointer to the [database connection] object 3127** and the X argument is unused. 3128** </dl> 3129*/ 3130#define SQLITE_TRACE_STMT 0x01 3131#define SQLITE_TRACE_PROFILE 0x02 3132#define SQLITE_TRACE_ROW 0x04 3133#define SQLITE_TRACE_CLOSE 0x08 3134 3135/* 3136** CAPI3REF: SQL Trace Hook 3137** METHOD: sqlite3 3138** 3139** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback 3140** function X against [database connection] D, using property mask M 3141** and context pointer P. ^If the X callback is 3142** NULL or if the M mask is zero, then tracing is disabled. The 3143** M argument should be the bitwise OR-ed combination of 3144** zero or more [SQLITE_TRACE] constants. 3145** 3146** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 3147** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2(). 3148** 3149** ^The X callback is invoked whenever any of the events identified by 3150** mask M occur. ^The integer return value from the callback is currently 3151** ignored, though this may change in future releases. Callback 3152** implementations should return zero to ensure future compatibility. 3153** 3154** ^A trace callback is invoked with four arguments: callback(T,C,P,X). 3155** ^The T argument is one of the [SQLITE_TRACE] 3156** constants to indicate why the callback was invoked. 3157** ^The C argument is a copy of the context pointer. 3158** The P and X arguments are pointers whose meanings depend on T. 3159** 3160** The sqlite3_trace_v2() interface is intended to replace the legacy 3161** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which 3162** are deprecated. 3163*/ 3164int sqlite3_trace_v2( 3165 sqlite3*, 3166 unsigned uMask, 3167 int(*xCallback)(unsigned,void*,void*,void*), 3168 void *pCtx 3169); 3170 3171/* 3172** CAPI3REF: Query Progress Callbacks 3173** METHOD: sqlite3 3174** 3175** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 3176** function X to be invoked periodically during long running calls to 3177** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 3178** database connection D. An example use for this 3179** interface is to keep a GUI updated during a large query. 3180** 3181** ^The parameter P is passed through as the only parameter to the 3182** callback function X. ^The parameter N is the approximate number of 3183** [virtual machine instructions] that are evaluated between successive 3184** invocations of the callback X. ^If N is less than one then the progress 3185** handler is disabled. 3186** 3187** ^Only a single progress handler may be defined at one time per 3188** [database connection]; setting a new progress handler cancels the 3189** old one. ^Setting parameter X to NULL disables the progress handler. 3190** ^The progress handler is also disabled by setting N to a value less 3191** than 1. 3192** 3193** ^If the progress callback returns non-zero, the operation is 3194** interrupted. This feature can be used to implement a 3195** "Cancel" button on a GUI progress dialog box. 3196** 3197** The progress handler callback must not do anything that will modify 3198** the database connection that invoked the progress handler. 3199** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3200** database connections for the meaning of "modify" in this paragraph. 3201** 3202*/ 3203void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 3204 3205/* 3206** CAPI3REF: Opening A New Database Connection 3207** CONSTRUCTOR: sqlite3 3208** 3209** ^These routines open an SQLite database file as specified by the 3210** filename argument. ^The filename argument is interpreted as UTF-8 for 3211** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 3212** order for sqlite3_open16(). ^(A [database connection] handle is usually 3213** returned in *ppDb, even if an error occurs. The only exception is that 3214** if SQLite is unable to allocate memory to hold the [sqlite3] object, 3215** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 3216** object.)^ ^(If the database is opened (and/or created) successfully, then 3217** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 3218** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 3219** an English language description of the error following a failure of any 3220** of the sqlite3_open() routines. 3221** 3222** ^The default encoding will be UTF-8 for databases created using 3223** sqlite3_open() or sqlite3_open_v2(). ^The default encoding for databases 3224** created using sqlite3_open16() will be UTF-16 in the native byte order. 3225** 3226** Whether or not an error occurs when it is opened, resources 3227** associated with the [database connection] handle should be released by 3228** passing it to [sqlite3_close()] when it is no longer required. 3229** 3230** The sqlite3_open_v2() interface works like sqlite3_open() 3231** except that it accepts two additional parameters for additional control 3232** over the new database connection. ^(The flags parameter to 3233** sqlite3_open_v2() can take one of 3234** the following three values, optionally combined with the 3235** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 3236** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 3237** 3238** <dl> 3239** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 3240** <dd>The database is opened in read-only mode. If the database does not 3241** already exist, an error is returned.</dd>)^ 3242** 3243** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 3244** <dd>The database is opened for reading and writing if possible, or reading 3245** only if the file is write protected by the operating system. In either 3246** case the database must already exist, otherwise an error is returned.</dd>)^ 3247** 3248** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 3249** <dd>The database is opened for reading and writing, and is created if 3250** it does not already exist. This is the behavior that is always used for 3251** sqlite3_open() and sqlite3_open16().</dd>)^ 3252** </dl> 3253** 3254** If the 3rd parameter to sqlite3_open_v2() is not one of the 3255** combinations shown above optionally combined with other 3256** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 3257** then the behavior is undefined. 3258** 3259** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 3260** opens in the multi-thread [threading mode] as long as the single-thread 3261** mode has not been set at compile-time or start-time. ^If the 3262** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 3263** in the serialized [threading mode] unless single-thread was 3264** previously selected at compile-time or start-time. 3265** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 3266** eligible to use [shared cache mode], regardless of whether or not shared 3267** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 3268** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 3269** participate in [shared cache mode] even if it is enabled. 3270** 3271** ^The fourth parameter to sqlite3_open_v2() is the name of the 3272** [sqlite3_vfs] object that defines the operating system interface that 3273** the new database connection should use. ^If the fourth parameter is 3274** a NULL pointer then the default [sqlite3_vfs] object is used. 3275** 3276** ^If the filename is ":memory:", then a private, temporary in-memory database 3277** is created for the connection. ^This in-memory database will vanish when 3278** the database connection is closed. Future versions of SQLite might 3279** make use of additional special filenames that begin with the ":" character. 3280** It is recommended that when a database filename actually does begin with 3281** a ":" character you should prefix the filename with a pathname such as 3282** "./" to avoid ambiguity. 3283** 3284** ^If the filename is an empty string, then a private, temporary 3285** on-disk database will be created. ^This private database will be 3286** automatically deleted as soon as the database connection is closed. 3287** 3288** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 3289** 3290** ^If [URI filename] interpretation is enabled, and the filename argument 3291** begins with "file:", then the filename is interpreted as a URI. ^URI 3292** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 3293** set in the third argument to sqlite3_open_v2(), or if it has 3294** been enabled globally using the [SQLITE_CONFIG_URI] option with the 3295** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 3296** URI filename interpretation is turned off 3297** by default, but future releases of SQLite might enable URI filename 3298** interpretation by default. See "[URI filenames]" for additional 3299** information. 3300** 3301** URI filenames are parsed according to RFC 3986. ^If the URI contains an 3302** authority, then it must be either an empty string or the string 3303** "localhost". ^If the authority is not an empty string or "localhost", an 3304** error is returned to the caller. ^The fragment component of a URI, if 3305** present, is ignored. 3306** 3307** ^SQLite uses the path component of the URI as the name of the disk file 3308** which contains the database. ^If the path begins with a '/' character, 3309** then it is interpreted as an absolute path. ^If the path does not begin 3310** with a '/' (meaning that the authority section is omitted from the URI) 3311** then the path is interpreted as a relative path. 3312** ^(On windows, the first component of an absolute path 3313** is a drive specification (e.g. "C:").)^ 3314** 3315** [[core URI query parameters]] 3316** The query component of a URI may contain parameters that are interpreted 3317** either by SQLite itself, or by a [VFS | custom VFS implementation]. 3318** SQLite and its built-in [VFSes] interpret the 3319** following query parameters: 3320** 3321** <ul> 3322** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 3323** a VFS object that provides the operating system interface that should 3324** be used to access the database file on disk. ^If this option is set to 3325** an empty string the default VFS object is used. ^Specifying an unknown 3326** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 3327** present, then the VFS specified by the option takes precedence over 3328** the value passed as the fourth parameter to sqlite3_open_v2(). 3329** 3330** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw", 3331** "rwc", or "memory". Attempting to set it to any other value is 3332** an error)^. 3333** ^If "ro" is specified, then the database is opened for read-only 3334** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 3335** third argument to sqlite3_open_v2(). ^If the mode option is set to 3336** "rw", then the database is opened for read-write (but not create) 3337** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 3338** been set. ^Value "rwc" is equivalent to setting both 3339** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If the mode option is 3340** set to "memory" then a pure [in-memory database] that never reads 3341** or writes from disk is used. ^It is an error to specify a value for 3342** the mode parameter that is less restrictive than that specified by 3343** the flags passed in the third parameter to sqlite3_open_v2(). 3344** 3345** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 3346** "private". ^Setting it to "shared" is equivalent to setting the 3347** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 3348** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 3349** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 3350** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 3351** a URI filename, its value overrides any behavior requested by setting 3352** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 3353** 3354** <li> <b>psow</b>: ^The psow parameter indicates whether or not the 3355** [powersafe overwrite] property does or does not apply to the 3356** storage media on which the database file resides. 3357** 3358** <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter 3359** which if set disables file locking in rollback journal modes. This 3360** is useful for accessing a database on a filesystem that does not 3361** support locking. Caution: Database corruption might result if two 3362** or more processes write to the same database and any one of those 3363** processes uses nolock=1. 3364** 3365** <li> <b>immutable</b>: ^The immutable parameter is a boolean query 3366** parameter that indicates that the database file is stored on 3367** read-only media. ^When immutable is set, SQLite assumes that the 3368** database file cannot be changed, even by a process with higher 3369** privilege, and so the database is opened read-only and all locking 3370** and change detection is disabled. Caution: Setting the immutable 3371** property on a database file that does in fact change can result 3372** in incorrect query results and/or [SQLITE_CORRUPT] errors. 3373** See also: [SQLITE_IOCAP_IMMUTABLE]. 3374** 3375** </ul> 3376** 3377** ^Specifying an unknown parameter in the query component of a URI is not an 3378** error. Future versions of SQLite might understand additional query 3379** parameters. See "[query parameters with special meaning to SQLite]" for 3380** additional information. 3381** 3382** [[URI filename examples]] <h3>URI filename examples</h3> 3383** 3384** <table border="1" align=center cellpadding=5> 3385** <tr><th> URI filenames <th> Results 3386** <tr><td> file:data.db <td> 3387** Open the file "data.db" in the current directory. 3388** <tr><td> file:/home/fred/data.db<br> 3389** file:///home/fred/data.db <br> 3390** file://localhost/home/fred/data.db <br> <td> 3391** Open the database file "/home/fred/data.db". 3392** <tr><td> file://darkstar/home/fred/data.db <td> 3393** An error. "darkstar" is not a recognized authority. 3394** <tr><td style="white-space:nowrap"> 3395** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 3396** <td> Windows only: Open the file "data.db" on fred's desktop on drive 3397** C:. Note that the %20 escaping in this example is not strictly 3398** necessary - space characters can be used literally 3399** in URI filenames. 3400** <tr><td> file:data.db?mode=ro&cache=private <td> 3401** Open file "data.db" in the current directory for read-only access. 3402** Regardless of whether or not shared-cache mode is enabled by 3403** default, use a private cache. 3404** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td> 3405** Open file "/home/fred/data.db". Use the special VFS "unix-dotfile" 3406** that uses dot-files in place of posix advisory locking. 3407** <tr><td> file:data.db?mode=readonly <td> 3408** An error. "readonly" is not a valid option for the "mode" parameter. 3409** </table> 3410** 3411** ^URI hexadecimal escape sequences (%HH) are supported within the path and 3412** query components of a URI. A hexadecimal escape sequence consists of a 3413** percent sign - "%" - followed by exactly two hexadecimal digits 3414** specifying an octet value. ^Before the path or query components of a 3415** URI filename are interpreted, they are encoded using UTF-8 and all 3416** hexadecimal escape sequences replaced by a single byte containing the 3417** corresponding octet. If this process generates an invalid UTF-8 encoding, 3418** the results are undefined. 3419** 3420** <b>Note to Windows users:</b> The encoding used for the filename argument 3421** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 3422** codepage is currently defined. Filenames containing international 3423** characters must be converted to UTF-8 prior to passing them into 3424** sqlite3_open() or sqlite3_open_v2(). 3425** 3426** <b>Note to Windows Runtime users:</b> The temporary directory must be set 3427** prior to calling sqlite3_open() or sqlite3_open_v2(). Otherwise, various 3428** features that require the use of temporary files may fail. 3429** 3430** See also: [sqlite3_temp_directory] 3431*/ 3432int sqlite3_open( 3433 const char *filename, /* Database filename (UTF-8) */ 3434 sqlite3 **ppDb /* OUT: SQLite db handle */ 3435); 3436int sqlite3_open16( 3437 const void *filename, /* Database filename (UTF-16) */ 3438 sqlite3 **ppDb /* OUT: SQLite db handle */ 3439); 3440int sqlite3_open_v2( 3441 const char *filename, /* Database filename (UTF-8) */ 3442 sqlite3 **ppDb, /* OUT: SQLite db handle */ 3443 int flags, /* Flags */ 3444 const char *zVfs /* Name of VFS module to use */ 3445); 3446 3447/* 3448** CAPI3REF: Obtain Values For URI Parameters 3449** 3450** These are utility routines, useful to VFS implementations, that check 3451** to see if a database file was a URI that contained a specific query 3452** parameter, and if so obtains the value of that query parameter. 3453** 3454** If F is the database filename pointer passed into the xOpen() method of 3455** a VFS implementation when the flags parameter to xOpen() has one or 3456** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 3457** P is the name of the query parameter, then 3458** sqlite3_uri_parameter(F,P) returns the value of the P 3459** parameter if it exists or a NULL pointer if P does not appear as a 3460** query parameter on F. If P is a query parameter of F 3461** has no explicit value, then sqlite3_uri_parameter(F,P) returns 3462** a pointer to an empty string. 3463** 3464** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 3465** parameter and returns true (1) or false (0) according to the value 3466** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 3467** value of query parameter P is one of "yes", "true", or "on" in any 3468** case or if the value begins with a non-zero number. The 3469** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 3470** query parameter P is one of "no", "false", or "off" in any case or 3471** if the value begins with a numeric zero. If P is not a query 3472** parameter on F or if the value of P is does not match any of the 3473** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 3474** 3475** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 3476** 64-bit signed integer and returns that integer, or D if P does not 3477** exist. If the value of P is something other than an integer, then 3478** zero is returned. 3479** 3480** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 3481** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 3482** is not a database file pathname pointer that SQLite passed into the xOpen 3483** VFS method, then the behavior of this routine is undefined and probably 3484** undesirable. 3485** 3486** See the [URI filename] documentation for additional information. 3487*/ 3488const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 3489int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 3490sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 3491 3492 3493/* 3494** CAPI3REF: Error Codes And Messages 3495** METHOD: sqlite3 3496** 3497** ^If the most recent sqlite3_* API call associated with 3498** [database connection] D failed, then the sqlite3_errcode(D) interface 3499** returns the numeric [result code] or [extended result code] for that 3500** API call. 3501** ^The sqlite3_extended_errcode() 3502** interface is the same except that it always returns the 3503** [extended result code] even when extended result codes are 3504** disabled. 3505** 3506** The values returned by sqlite3_errcode() and/or 3507** sqlite3_extended_errcode() might change with each API call. 3508** Except, there are some interfaces that are guaranteed to never 3509** change the value of the error code. The error-code preserving 3510** interfaces are: 3511** 3512** <ul> 3513** <li> sqlite3_errcode() 3514** <li> sqlite3_extended_errcode() 3515** <li> sqlite3_errmsg() 3516** <li> sqlite3_errmsg16() 3517** </ul> 3518** 3519** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 3520** text that describes the error, as either UTF-8 or UTF-16 respectively. 3521** ^(Memory to hold the error message string is managed internally. 3522** The application does not need to worry about freeing the result. 3523** However, the error string might be overwritten or deallocated by 3524** subsequent calls to other SQLite interface functions.)^ 3525** 3526** ^The sqlite3_errstr() interface returns the English-language text 3527** that describes the [result code], as UTF-8. 3528** ^(Memory to hold the error message string is managed internally 3529** and must not be freed by the application)^. 3530** 3531** When the serialized [threading mode] is in use, it might be the 3532** case that a second error occurs on a separate thread in between 3533** the time of the first error and the call to these interfaces. 3534** When that happens, the second error will be reported since these 3535** interfaces always report the most recent result. To avoid 3536** this, each thread can obtain exclusive use of the [database connection] D 3537** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 3538** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 3539** all calls to the interfaces listed here are completed. 3540** 3541** If an interface fails with SQLITE_MISUSE, that means the interface 3542** was invoked incorrectly by the application. In that case, the 3543** error code and message may or may not be set. 3544*/ 3545int sqlite3_errcode(sqlite3 *db); 3546int sqlite3_extended_errcode(sqlite3 *db); 3547const char *sqlite3_errmsg(sqlite3*); 3548const void *sqlite3_errmsg16(sqlite3*); 3549const char *sqlite3_errstr(int); 3550 3551/* 3552** CAPI3REF: Prepared Statement Object 3553** KEYWORDS: {prepared statement} {prepared statements} 3554** 3555** An instance of this object represents a single SQL statement that 3556** has been compiled into binary form and is ready to be evaluated. 3557** 3558** Think of each SQL statement as a separate computer program. The 3559** original SQL text is source code. A prepared statement object 3560** is the compiled object code. All SQL must be converted into a 3561** prepared statement before it can be run. 3562** 3563** The life-cycle of a prepared statement object usually goes like this: 3564** 3565** <ol> 3566** <li> Create the prepared statement object using [sqlite3_prepare_v2()]. 3567** <li> Bind values to [parameters] using the sqlite3_bind_*() 3568** interfaces. 3569** <li> Run the SQL by calling [sqlite3_step()] one or more times. 3570** <li> Reset the prepared statement using [sqlite3_reset()] then go back 3571** to step 2. Do this zero or more times. 3572** <li> Destroy the object using [sqlite3_finalize()]. 3573** </ol> 3574*/ 3575typedef struct sqlite3_stmt sqlite3_stmt; 3576 3577/* 3578** CAPI3REF: Run-time Limits 3579** METHOD: sqlite3 3580** 3581** ^(This interface allows the size of various constructs to be limited 3582** on a connection by connection basis. The first parameter is the 3583** [database connection] whose limit is to be set or queried. The 3584** second parameter is one of the [limit categories] that define a 3585** class of constructs to be size limited. The third parameter is the 3586** new limit for that construct.)^ 3587** 3588** ^If the new limit is a negative number, the limit is unchanged. 3589** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 3590** [limits | hard upper bound] 3591** set at compile-time by a C preprocessor macro called 3592** [limits | SQLITE_MAX_<i>NAME</i>]. 3593** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 3594** ^Attempts to increase a limit above its hard upper bound are 3595** silently truncated to the hard upper bound. 3596** 3597** ^Regardless of whether or not the limit was changed, the 3598** [sqlite3_limit()] interface returns the prior value of the limit. 3599** ^Hence, to find the current value of a limit without changing it, 3600** simply invoke this interface with the third parameter set to -1. 3601** 3602** Run-time limits are intended for use in applications that manage 3603** both their own internal database and also databases that are controlled 3604** by untrusted external sources. An example application might be a 3605** web browser that has its own databases for storing history and 3606** separate databases controlled by JavaScript applications downloaded 3607** off the Internet. The internal databases can be given the 3608** large, default limits. Databases managed by external sources can 3609** be given much smaller limits designed to prevent a denial of service 3610** attack. Developers might also want to use the [sqlite3_set_authorizer()] 3611** interface to further control untrusted SQL. The size of the database 3612** created by an untrusted script can be contained using the 3613** [max_page_count] [PRAGMA]. 3614** 3615** New run-time limit categories may be added in future releases. 3616*/ 3617int sqlite3_limit(sqlite3*, int id, int newVal); 3618 3619/* 3620** CAPI3REF: Run-Time Limit Categories 3621** KEYWORDS: {limit category} {*limit categories} 3622** 3623** These constants define various performance limits 3624** that can be lowered at run-time using [sqlite3_limit()]. 3625** The synopsis of the meanings of the various limits is shown below. 3626** Additional information is available at [limits | Limits in SQLite]. 3627** 3628** <dl> 3629** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 3630** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 3631** 3632** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 3633** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 3634** 3635** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 3636** <dd>The maximum number of columns in a table definition or in the 3637** result set of a [SELECT] or the maximum number of columns in an index 3638** or in an ORDER BY or GROUP BY clause.</dd>)^ 3639** 3640** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 3641** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 3642** 3643** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 3644** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 3645** 3646** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 3647** <dd>The maximum number of instructions in a virtual machine program 3648** used to implement an SQL statement. If [sqlite3_prepare_v2()] or 3649** the equivalent tries to allocate space for more than this many opcodes 3650** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^ 3651** 3652** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 3653** <dd>The maximum number of arguments on a function.</dd>)^ 3654** 3655** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 3656** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 3657** 3658** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 3659** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 3660** <dd>The maximum length of the pattern argument to the [LIKE] or 3661** [GLOB] operators.</dd>)^ 3662** 3663** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 3664** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 3665** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 3666** 3667** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 3668** <dd>The maximum depth of recursion for triggers.</dd>)^ 3669** 3670** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt> 3671** <dd>The maximum number of auxiliary worker threads that a single 3672** [prepared statement] may start.</dd>)^ 3673** </dl> 3674*/ 3675#define SQLITE_LIMIT_LENGTH 0 3676#define SQLITE_LIMIT_SQL_LENGTH 1 3677#define SQLITE_LIMIT_COLUMN 2 3678#define SQLITE_LIMIT_EXPR_DEPTH 3 3679#define SQLITE_LIMIT_COMPOUND_SELECT 4 3680#define SQLITE_LIMIT_VDBE_OP 5 3681#define SQLITE_LIMIT_FUNCTION_ARG 6 3682#define SQLITE_LIMIT_ATTACHED 7 3683#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 3684#define SQLITE_LIMIT_VARIABLE_NUMBER 9 3685#define SQLITE_LIMIT_TRIGGER_DEPTH 10 3686#define SQLITE_LIMIT_WORKER_THREADS 11 3687 3688/* 3689** CAPI3REF: Prepare Flags 3690** 3691** These constants define various flags that can be passed into 3692** "prepFlags" parameter of the [sqlite3_prepare_v3()] and 3693** [sqlite3_prepare16_v3()] interfaces. 3694** 3695** New flags may be added in future releases of SQLite. 3696** 3697** <dl> 3698** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt> 3699** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner 3700** that the prepared statement will be retained for a long time and 3701** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()] 3702** and [sqlite3_prepare16_v3()] assume that the prepared statement will 3703** be used just once or at most a few times and then destroyed using 3704** [sqlite3_finalize()] relatively soon. The current implementation acts 3705** on this hint by avoiding the use of [lookaside memory] so as not to 3706** deplete the limited store of lookaside memory. Future versions of 3707** SQLite may act on this hint differently. 3708** 3709** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt> 3710** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used 3711** to be required for any prepared statement that wanted to use the 3712** [sqlite3_normalized_sql()] interface. However, the 3713** [sqlite3_normalized_sql()] interface is now available to all 3714** prepared statements, regardless of whether or not they use this 3715** flag. 3716** 3717** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt> 3718** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler 3719** to return an error (error code SQLITE_ERROR) if the statement uses 3720** any virtual tables. 3721** </dl> 3722*/ 3723#define SQLITE_PREPARE_PERSISTENT 0x01 3724#define SQLITE_PREPARE_NORMALIZE 0x02 3725#define SQLITE_PREPARE_NO_VTAB 0x04 3726 3727/* 3728** CAPI3REF: Compiling An SQL Statement 3729** KEYWORDS: {SQL statement compiler} 3730** METHOD: sqlite3 3731** CONSTRUCTOR: sqlite3_stmt 3732** 3733** To execute an SQL statement, it must first be compiled into a byte-code 3734** program using one of these routines. Or, in other words, these routines 3735** are constructors for the [prepared statement] object. 3736** 3737** The preferred routine to use is [sqlite3_prepare_v2()]. The 3738** [sqlite3_prepare()] interface is legacy and should be avoided. 3739** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used 3740** for special purposes. 3741** 3742** The use of the UTF-8 interfaces is preferred, as SQLite currently 3743** does all parsing using UTF-8. The UTF-16 interfaces are provided 3744** as a convenience. The UTF-16 interfaces work by converting the 3745** input text into UTF-8, then invoking the corresponding UTF-8 interface. 3746** 3747** The first argument, "db", is a [database connection] obtained from a 3748** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 3749** [sqlite3_open16()]. The database connection must not have been closed. 3750** 3751** The second argument, "zSql", is the statement to be compiled, encoded 3752** as either UTF-8 or UTF-16. The sqlite3_prepare(), sqlite3_prepare_v2(), 3753** and sqlite3_prepare_v3() 3754** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(), 3755** and sqlite3_prepare16_v3() use UTF-16. 3756** 3757** ^If the nByte argument is negative, then zSql is read up to the 3758** first zero terminator. ^If nByte is positive, then it is the 3759** number of bytes read from zSql. ^If nByte is zero, then no prepared 3760** statement is generated. 3761** If the caller knows that the supplied string is nul-terminated, then 3762** there is a small performance advantage to passing an nByte parameter that 3763** is the number of bytes in the input string <i>including</i> 3764** the nul-terminator. 3765** 3766** ^If pzTail is not NULL then *pzTail is made to point to the first byte 3767** past the end of the first SQL statement in zSql. These routines only 3768** compile the first statement in zSql, so *pzTail is left pointing to 3769** what remains uncompiled. 3770** 3771** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 3772** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 3773** to NULL. ^If the input text contains no SQL (if the input is an empty 3774** string or a comment) then *ppStmt is set to NULL. 3775** The calling procedure is responsible for deleting the compiled 3776** SQL statement using [sqlite3_finalize()] after it has finished with it. 3777** ppStmt may not be NULL. 3778** 3779** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 3780** otherwise an [error code] is returned. 3781** 3782** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(), 3783** and sqlite3_prepare16_v3() interfaces are recommended for all new programs. 3784** The older interfaces (sqlite3_prepare() and sqlite3_prepare16()) 3785** are retained for backwards compatibility, but their use is discouraged. 3786** ^In the "vX" interfaces, the prepared statement 3787** that is returned (the [sqlite3_stmt] object) contains a copy of the 3788** original SQL text. This causes the [sqlite3_step()] interface to 3789** behave differently in three ways: 3790** 3791** <ol> 3792** <li> 3793** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 3794** always used to do, [sqlite3_step()] will automatically recompile the SQL 3795** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY] 3796** retries will occur before sqlite3_step() gives up and returns an error. 3797** </li> 3798** 3799** <li> 3800** ^When an error occurs, [sqlite3_step()] will return one of the detailed 3801** [error codes] or [extended error codes]. ^The legacy behavior was that 3802** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 3803** and the application would have to make a second call to [sqlite3_reset()] 3804** in order to find the underlying cause of the problem. With the "v2" prepare 3805** interfaces, the underlying reason for the error is returned immediately. 3806** </li> 3807** 3808** <li> 3809** ^If the specific value bound to [parameter | host parameter] in the 3810** WHERE clause might influence the choice of query plan for a statement, 3811** then the statement will be automatically recompiled, as if there had been 3812** a schema change, on the first [sqlite3_step()] call following any change 3813** to the [sqlite3_bind_text | bindings] of that [parameter]. 3814** ^The specific value of WHERE-clause [parameter] might influence the 3815** choice of query plan if the parameter is the left-hand side of a [LIKE] 3816** or [GLOB] operator or if the parameter is compared to an indexed column 3817** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled. 3818** </li> 3819** </ol> 3820** 3821** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having 3822** the extra prepFlags parameter, which is a bit array consisting of zero or 3823** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags. ^The 3824** sqlite3_prepare_v2() interface works exactly the same as 3825** sqlite3_prepare_v3() with a zero prepFlags parameter. 3826*/ 3827int sqlite3_prepare( 3828 sqlite3 *db, /* Database handle */ 3829 const char *zSql, /* SQL statement, UTF-8 encoded */ 3830 int nByte, /* Maximum length of zSql in bytes. */ 3831 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3832 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3833); 3834int sqlite3_prepare_v2( 3835 sqlite3 *db, /* Database handle */ 3836 const char *zSql, /* SQL statement, UTF-8 encoded */ 3837 int nByte, /* Maximum length of zSql in bytes. */ 3838 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3839 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3840); 3841int sqlite3_prepare_v3( 3842 sqlite3 *db, /* Database handle */ 3843 const char *zSql, /* SQL statement, UTF-8 encoded */ 3844 int nByte, /* Maximum length of zSql in bytes. */ 3845 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3846 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3847 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 3848); 3849int sqlite3_prepare16( 3850 sqlite3 *db, /* Database handle */ 3851 const void *zSql, /* SQL statement, UTF-16 encoded */ 3852 int nByte, /* Maximum length of zSql in bytes. */ 3853 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3854 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3855); 3856int sqlite3_prepare16_v2( 3857 sqlite3 *db, /* Database handle */ 3858 const void *zSql, /* SQL statement, UTF-16 encoded */ 3859 int nByte, /* Maximum length of zSql in bytes. */ 3860 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3861 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3862); 3863int sqlite3_prepare16_v3( 3864 sqlite3 *db, /* Database handle */ 3865 const void *zSql, /* SQL statement, UTF-16 encoded */ 3866 int nByte, /* Maximum length of zSql in bytes. */ 3867 unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */ 3868 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 3869 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 3870); 3871 3872/* 3873** CAPI3REF: Retrieving Statement SQL 3874** METHOD: sqlite3_stmt 3875** 3876** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8 3877** SQL text used to create [prepared statement] P if P was 3878** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], 3879** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 3880** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8 3881** string containing the SQL text of prepared statement P with 3882** [bound parameters] expanded. 3883** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8 3884** string containing the normalized SQL text of prepared statement P. The 3885** semantics used to normalize a SQL statement are unspecified and subject 3886** to change. At a minimum, literal values will be replaced with suitable 3887** placeholders. 3888** 3889** ^(For example, if a prepared statement is created using the SQL 3890** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345 3891** and parameter :xyz is unbound, then sqlite3_sql() will return 3892** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql() 3893** will return "SELECT 2345,NULL".)^ 3894** 3895** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory 3896** is available to hold the result, or if the result would exceed the 3897** the maximum string length determined by the [SQLITE_LIMIT_LENGTH]. 3898** 3899** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of 3900** bound parameter expansions. ^The [SQLITE_OMIT_TRACE] compile-time 3901** option causes sqlite3_expanded_sql() to always return NULL. 3902** 3903** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P) 3904** are managed by SQLite and are automatically freed when the prepared 3905** statement is finalized. 3906** ^The string returned by sqlite3_expanded_sql(P), on the other hand, 3907** is obtained from [sqlite3_malloc()] and must be free by the application 3908** by passing it to [sqlite3_free()]. 3909*/ 3910const char *sqlite3_sql(sqlite3_stmt *pStmt); 3911char *sqlite3_expanded_sql(sqlite3_stmt *pStmt); 3912const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt); 3913 3914/* 3915** CAPI3REF: Determine If An SQL Statement Writes The Database 3916** METHOD: sqlite3_stmt 3917** 3918** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 3919** and only if the [prepared statement] X makes no direct changes to 3920** the content of the database file. 3921** 3922** Note that [application-defined SQL functions] or 3923** [virtual tables] might change the database indirectly as a side effect. 3924** ^(For example, if an application defines a function "eval()" that 3925** calls [sqlite3_exec()], then the following SQL statement would 3926** change the database file through side-effects: 3927** 3928** <blockquote><pre> 3929** SELECT eval('DELETE FROM t1') FROM t2; 3930** </pre></blockquote> 3931** 3932** But because the [SELECT] statement does not change the database file 3933** directly, sqlite3_stmt_readonly() would still return true.)^ 3934** 3935** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3936** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3937** since the statements themselves do not actually modify the database but 3938** rather they control the timing of when other statements modify the 3939** database. ^The [ATTACH] and [DETACH] statements also cause 3940** sqlite3_stmt_readonly() to return true since, while those statements 3941** change the configuration of a database connection, they do not make 3942** changes to the content of the database files on disk. 3943** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since 3944** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and 3945** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so 3946** sqlite3_stmt_readonly() returns false for those commands. 3947*/ 3948int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3949 3950/* 3951** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement 3952** METHOD: sqlite3_stmt 3953** 3954** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the 3955** prepared statement S is an EXPLAIN statement, or 2 if the 3956** statement S is an EXPLAIN QUERY PLAN. 3957** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is 3958** an ordinary statement or a NULL pointer. 3959*/ 3960int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt); 3961 3962/* 3963** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3964** METHOD: sqlite3_stmt 3965** 3966** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3967** [prepared statement] S has been stepped at least once using 3968** [sqlite3_step(S)] but has neither run to completion (returned 3969** [SQLITE_DONE] from [sqlite3_step(S)]) nor 3970** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3971** interface returns false if S is a NULL pointer. If S is not a 3972** NULL pointer and is not a pointer to a valid [prepared statement] 3973** object, then the behavior is undefined and probably undesirable. 3974** 3975** This interface can be used in combination [sqlite3_next_stmt()] 3976** to locate all prepared statements associated with a database 3977** connection that are in need of being reset. This can be used, 3978** for example, in diagnostic routines to search for prepared 3979** statements that are holding a transaction open. 3980*/ 3981int sqlite3_stmt_busy(sqlite3_stmt*); 3982 3983/* 3984** CAPI3REF: Dynamically Typed Value Object 3985** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3986** 3987** SQLite uses the sqlite3_value object to represent all values 3988** that can be stored in a database table. SQLite uses dynamic typing 3989** for the values it stores. ^Values stored in sqlite3_value objects 3990** can be integers, floating point values, strings, BLOBs, or NULL. 3991** 3992** An sqlite3_value object may be either "protected" or "unprotected". 3993** Some interfaces require a protected sqlite3_value. Other interfaces 3994** will accept either a protected or an unprotected sqlite3_value. 3995** Every interface that accepts sqlite3_value arguments specifies 3996** whether or not it requires a protected sqlite3_value. The 3997** [sqlite3_value_dup()] interface can be used to construct a new 3998** protected sqlite3_value from an unprotected sqlite3_value. 3999** 4000** The terms "protected" and "unprotected" refer to whether or not 4001** a mutex is held. An internal mutex is held for a protected 4002** sqlite3_value object but no mutex is held for an unprotected 4003** sqlite3_value object. If SQLite is compiled to be single-threaded 4004** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 4005** or if SQLite is run in one of reduced mutex modes 4006** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 4007** then there is no distinction between protected and unprotected 4008** sqlite3_value objects and they can be used interchangeably. However, 4009** for maximum code portability it is recommended that applications 4010** still make the distinction between protected and unprotected 4011** sqlite3_value objects even when not strictly required. 4012** 4013** ^The sqlite3_value objects that are passed as parameters into the 4014** implementation of [application-defined SQL functions] are protected. 4015** ^The sqlite3_value object returned by 4016** [sqlite3_column_value()] is unprotected. 4017** Unprotected sqlite3_value objects may only be used as arguments 4018** to [sqlite3_result_value()], [sqlite3_bind_value()], and 4019** [sqlite3_value_dup()]. 4020** The [sqlite3_value_blob | sqlite3_value_type()] family of 4021** interfaces require protected sqlite3_value objects. 4022*/ 4023typedef struct sqlite3_value sqlite3_value; 4024 4025/* 4026** CAPI3REF: SQL Function Context Object 4027** 4028** The context in which an SQL function executes is stored in an 4029** sqlite3_context object. ^A pointer to an sqlite3_context object 4030** is always first parameter to [application-defined SQL functions]. 4031** The application-defined SQL function implementation will pass this 4032** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 4033** [sqlite3_aggregate_context()], [sqlite3_user_data()], 4034** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 4035** and/or [sqlite3_set_auxdata()]. 4036*/ 4037typedef struct sqlite3_context sqlite3_context; 4038 4039/* 4040** CAPI3REF: Binding Values To Prepared Statements 4041** KEYWORDS: {host parameter} {host parameters} {host parameter name} 4042** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 4043** METHOD: sqlite3_stmt 4044** 4045** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 4046** literals may be replaced by a [parameter] that matches one of following 4047** templates: 4048** 4049** <ul> 4050** <li> ? 4051** <li> ?NNN 4052** <li> :VVV 4053** <li> @VVV 4054** <li> $VVV 4055** </ul> 4056** 4057** In the templates above, NNN represents an integer literal, 4058** and VVV represents an alphanumeric identifier.)^ ^The values of these 4059** parameters (also called "host parameter names" or "SQL parameters") 4060** can be set using the sqlite3_bind_*() routines defined here. 4061** 4062** ^The first argument to the sqlite3_bind_*() routines is always 4063** a pointer to the [sqlite3_stmt] object returned from 4064** [sqlite3_prepare_v2()] or its variants. 4065** 4066** ^The second argument is the index of the SQL parameter to be set. 4067** ^The leftmost SQL parameter has an index of 1. ^When the same named 4068** SQL parameter is used more than once, second and subsequent 4069** occurrences have the same index as the first occurrence. 4070** ^The index for named parameters can be looked up using the 4071** [sqlite3_bind_parameter_index()] API if desired. ^The index 4072** for "?NNN" parameters is the value of NNN. 4073** ^The NNN value must be between 1 and the [sqlite3_limit()] 4074** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 4075** 4076** ^The third argument is the value to bind to the parameter. 4077** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4078** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter 4079** is ignored and the end result is the same as sqlite3_bind_null(). 4080** 4081** ^(In those routines that have a fourth argument, its value is the 4082** number of bytes in the parameter. To be clear: the value is the 4083** number of <u>bytes</u> in the value, not the number of characters.)^ 4084** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16() 4085** is negative, then the length of the string is 4086** the number of bytes up to the first zero terminator. 4087** If the fourth parameter to sqlite3_bind_blob() is negative, then 4088** the behavior is undefined. 4089** If a non-negative fourth parameter is provided to sqlite3_bind_text() 4090** or sqlite3_bind_text16() or sqlite3_bind_text64() then 4091** that parameter must be the byte offset 4092** where the NUL terminator would occur assuming the string were NUL 4093** terminated. If any NUL characters occur at byte offsets less than 4094** the value of the fourth parameter then the resulting string value will 4095** contain embedded NULs. The result of expressions involving strings 4096** with embedded NULs is undefined. 4097** 4098** ^The fifth argument to the BLOB and string binding interfaces 4099** is a destructor used to dispose of the BLOB or 4100** string after SQLite has finished with it. ^The destructor is called 4101** to dispose of the BLOB or string even if the call to the bind API fails, 4102** except the destructor is not called if the third parameter is a NULL 4103** pointer or the fourth parameter is negative. 4104** ^If the fifth argument is 4105** the special value [SQLITE_STATIC], then SQLite assumes that the 4106** information is in static, unmanaged space and does not need to be freed. 4107** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 4108** SQLite makes its own private copy of the data immediately, before 4109** the sqlite3_bind_*() routine returns. 4110** 4111** ^The sixth argument to sqlite3_bind_text64() must be one of 4112** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE] 4113** to specify the encoding of the text in the third parameter. If 4114** the sixth argument to sqlite3_bind_text64() is not one of the 4115** allowed values shown above, or if the text encoding is different 4116** from the encoding specified by the sixth parameter, then the behavior 4117** is undefined. 4118** 4119** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 4120** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 4121** (just an integer to hold its size) while it is being processed. 4122** Zeroblobs are intended to serve as placeholders for BLOBs whose 4123** content is later written using 4124** [sqlite3_blob_open | incremental BLOB I/O] routines. 4125** ^A negative value for the zeroblob results in a zero-length BLOB. 4126** 4127** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in 4128** [prepared statement] S to have an SQL value of NULL, but to also be 4129** associated with the pointer P of type T. ^D is either a NULL pointer or 4130** a pointer to a destructor function for P. ^SQLite will invoke the 4131** destructor D with a single argument of P when it is finished using 4132** P. The T parameter should be a static string, preferably a string 4133** literal. The sqlite3_bind_pointer() routine is part of the 4134** [pointer passing interface] added for SQLite 3.20.0. 4135** 4136** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 4137** for the [prepared statement] or with a prepared statement for which 4138** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 4139** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 4140** routine is passed a [prepared statement] that has been finalized, the 4141** result is undefined and probably harmful. 4142** 4143** ^Bindings are not cleared by the [sqlite3_reset()] routine. 4144** ^Unbound parameters are interpreted as NULL. 4145** 4146** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 4147** [error code] if anything goes wrong. 4148** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB 4149** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or 4150** [SQLITE_MAX_LENGTH]. 4151** ^[SQLITE_RANGE] is returned if the parameter 4152** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 4153** 4154** See also: [sqlite3_bind_parameter_count()], 4155** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 4156*/ 4157int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 4158int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64, 4159 void(*)(void*)); 4160int sqlite3_bind_double(sqlite3_stmt*, int, double); 4161int sqlite3_bind_int(sqlite3_stmt*, int, int); 4162int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 4163int sqlite3_bind_null(sqlite3_stmt*, int); 4164int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*)); 4165int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 4166int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64, 4167 void(*)(void*), unsigned char encoding); 4168int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 4169int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*)); 4170int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 4171int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64); 4172 4173/* 4174** CAPI3REF: Number Of SQL Parameters 4175** METHOD: sqlite3_stmt 4176** 4177** ^This routine can be used to find the number of [SQL parameters] 4178** in a [prepared statement]. SQL parameters are tokens of the 4179** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 4180** placeholders for values that are [sqlite3_bind_blob | bound] 4181** to the parameters at a later time. 4182** 4183** ^(This routine actually returns the index of the largest (rightmost) 4184** parameter. For all forms except ?NNN, this will correspond to the 4185** number of unique parameters. If parameters of the ?NNN form are used, 4186** there may be gaps in the list.)^ 4187** 4188** See also: [sqlite3_bind_blob|sqlite3_bind()], 4189** [sqlite3_bind_parameter_name()], and 4190** [sqlite3_bind_parameter_index()]. 4191*/ 4192int sqlite3_bind_parameter_count(sqlite3_stmt*); 4193 4194/* 4195** CAPI3REF: Name Of A Host Parameter 4196** METHOD: sqlite3_stmt 4197** 4198** ^The sqlite3_bind_parameter_name(P,N) interface returns 4199** the name of the N-th [SQL parameter] in the [prepared statement] P. 4200** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 4201** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 4202** respectively. 4203** In other words, the initial ":" or "$" or "@" or "?" 4204** is included as part of the name.)^ 4205** ^Parameters of the form "?" without a following integer have no name 4206** and are referred to as "nameless" or "anonymous parameters". 4207** 4208** ^The first host parameter has an index of 1, not 0. 4209** 4210** ^If the value N is out of range or if the N-th parameter is 4211** nameless, then NULL is returned. ^The returned string is 4212** always in UTF-8 encoding even if the named parameter was 4213** originally specified as UTF-16 in [sqlite3_prepare16()], 4214** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()]. 4215** 4216** See also: [sqlite3_bind_blob|sqlite3_bind()], 4217** [sqlite3_bind_parameter_count()], and 4218** [sqlite3_bind_parameter_index()]. 4219*/ 4220const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 4221 4222/* 4223** CAPI3REF: Index Of A Parameter With A Given Name 4224** METHOD: sqlite3_stmt 4225** 4226** ^Return the index of an SQL parameter given its name. ^The 4227** index value returned is suitable for use as the second 4228** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 4229** is returned if no matching parameter is found. ^The parameter 4230** name must be given in UTF-8 even if the original statement 4231** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or 4232** [sqlite3_prepare16_v3()]. 4233** 4234** See also: [sqlite3_bind_blob|sqlite3_bind()], 4235** [sqlite3_bind_parameter_count()], and 4236** [sqlite3_bind_parameter_name()]. 4237*/ 4238int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 4239 4240/* 4241** CAPI3REF: Reset All Bindings On A Prepared Statement 4242** METHOD: sqlite3_stmt 4243** 4244** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 4245** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 4246** ^Use this routine to reset all host parameters to NULL. 4247*/ 4248int sqlite3_clear_bindings(sqlite3_stmt*); 4249 4250/* 4251** CAPI3REF: Number Of Columns In A Result Set 4252** METHOD: sqlite3_stmt 4253** 4254** ^Return the number of columns in the result set returned by the 4255** [prepared statement]. ^If this routine returns 0, that means the 4256** [prepared statement] returns no data (for example an [UPDATE]). 4257** ^However, just because this routine returns a positive number does not 4258** mean that one or more rows of data will be returned. ^A SELECT statement 4259** will always have a positive sqlite3_column_count() but depending on the 4260** WHERE clause constraints and the table content, it might return no rows. 4261** 4262** See also: [sqlite3_data_count()] 4263*/ 4264int sqlite3_column_count(sqlite3_stmt *pStmt); 4265 4266/* 4267** CAPI3REF: Column Names In A Result Set 4268** METHOD: sqlite3_stmt 4269** 4270** ^These routines return the name assigned to a particular column 4271** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 4272** interface returns a pointer to a zero-terminated UTF-8 string 4273** and sqlite3_column_name16() returns a pointer to a zero-terminated 4274** UTF-16 string. ^The first parameter is the [prepared statement] 4275** that implements the [SELECT] statement. ^The second parameter is the 4276** column number. ^The leftmost column is number 0. 4277** 4278** ^The returned string pointer is valid until either the [prepared statement] 4279** is destroyed by [sqlite3_finalize()] or until the statement is automatically 4280** reprepared by the first call to [sqlite3_step()] for a particular run 4281** or until the next call to 4282** sqlite3_column_name() or sqlite3_column_name16() on the same column. 4283** 4284** ^If sqlite3_malloc() fails during the processing of either routine 4285** (for example during a conversion from UTF-8 to UTF-16) then a 4286** NULL pointer is returned. 4287** 4288** ^The name of a result column is the value of the "AS" clause for 4289** that column, if there is an AS clause. If there is no AS clause 4290** then the name of the column is unspecified and may change from 4291** one release of SQLite to the next. 4292*/ 4293const char *sqlite3_column_name(sqlite3_stmt*, int N); 4294const void *sqlite3_column_name16(sqlite3_stmt*, int N); 4295 4296/* 4297** CAPI3REF: Source Of Data In A Query Result 4298** METHOD: sqlite3_stmt 4299** 4300** ^These routines provide a means to determine the database, table, and 4301** table column that is the origin of a particular result column in 4302** [SELECT] statement. 4303** ^The name of the database or table or column can be returned as 4304** either a UTF-8 or UTF-16 string. ^The _database_ routines return 4305** the database name, the _table_ routines return the table name, and 4306** the origin_ routines return the column name. 4307** ^The returned string is valid until the [prepared statement] is destroyed 4308** using [sqlite3_finalize()] or until the statement is automatically 4309** reprepared by the first call to [sqlite3_step()] for a particular run 4310** or until the same information is requested 4311** again in a different encoding. 4312** 4313** ^The names returned are the original un-aliased names of the 4314** database, table, and column. 4315** 4316** ^The first argument to these interfaces is a [prepared statement]. 4317** ^These functions return information about the Nth result column returned by 4318** the statement, where N is the second function argument. 4319** ^The left-most column is column 0 for these routines. 4320** 4321** ^If the Nth column returned by the statement is an expression or 4322** subquery and is not a column value, then all of these functions return 4323** NULL. ^These routine might also return NULL if a memory allocation error 4324** occurs. ^Otherwise, they return the name of the attached database, table, 4325** or column that query result column was extracted from. 4326** 4327** ^As with all other SQLite APIs, those whose names end with "16" return 4328** UTF-16 encoded strings and the other functions return UTF-8. 4329** 4330** ^These APIs are only available if the library was compiled with the 4331** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 4332** 4333** If two or more threads call one or more of these routines against the same 4334** prepared statement and column at the same time then the results are 4335** undefined. 4336** 4337** If two or more threads call one or more 4338** [sqlite3_column_database_name | column metadata interfaces] 4339** for the same [prepared statement] and result column 4340** at the same time then the results are undefined. 4341*/ 4342const char *sqlite3_column_database_name(sqlite3_stmt*,int); 4343const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 4344const char *sqlite3_column_table_name(sqlite3_stmt*,int); 4345const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 4346const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 4347const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 4348 4349/* 4350** CAPI3REF: Declared Datatype Of A Query Result 4351** METHOD: sqlite3_stmt 4352** 4353** ^(The first parameter is a [prepared statement]. 4354** If this statement is a [SELECT] statement and the Nth column of the 4355** returned result set of that [SELECT] is a table column (not an 4356** expression or subquery) then the declared type of the table 4357** column is returned.)^ ^If the Nth column of the result set is an 4358** expression or subquery, then a NULL pointer is returned. 4359** ^The returned string is always UTF-8 encoded. 4360** 4361** ^(For example, given the database schema: 4362** 4363** CREATE TABLE t1(c1 VARIANT); 4364** 4365** and the following statement to be compiled: 4366** 4367** SELECT c1 + 1, c1 FROM t1; 4368** 4369** this routine would return the string "VARIANT" for the second result 4370** column (i==1), and a NULL pointer for the first result column (i==0).)^ 4371** 4372** ^SQLite uses dynamic run-time typing. ^So just because a column 4373** is declared to contain a particular type does not mean that the 4374** data stored in that column is of the declared type. SQLite is 4375** strongly typed, but the typing is dynamic not static. ^Type 4376** is associated with individual values, not with the containers 4377** used to hold those values. 4378*/ 4379const char *sqlite3_column_decltype(sqlite3_stmt*,int); 4380const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 4381 4382/* 4383** CAPI3REF: Evaluate An SQL Statement 4384** METHOD: sqlite3_stmt 4385** 4386** After a [prepared statement] has been prepared using any of 4387** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()], 4388** or [sqlite3_prepare16_v3()] or one of the legacy 4389** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 4390** must be called one or more times to evaluate the statement. 4391** 4392** The details of the behavior of the sqlite3_step() interface depend 4393** on whether the statement was prepared using the newer "vX" interfaces 4394** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()], 4395** [sqlite3_prepare16_v2()] or the older legacy 4396** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 4397** new "vX" interface is recommended for new applications but the legacy 4398** interface will continue to be supported. 4399** 4400** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 4401** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 4402** ^With the "v2" interface, any of the other [result codes] or 4403** [extended result codes] might be returned as well. 4404** 4405** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 4406** database locks it needs to do its job. ^If the statement is a [COMMIT] 4407** or occurs outside of an explicit transaction, then you can retry the 4408** statement. If the statement is not a [COMMIT] and occurs within an 4409** explicit transaction then you should rollback the transaction before 4410** continuing. 4411** 4412** ^[SQLITE_DONE] means that the statement has finished executing 4413** successfully. sqlite3_step() should not be called again on this virtual 4414** machine without first calling [sqlite3_reset()] to reset the virtual 4415** machine back to its initial state. 4416** 4417** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 4418** is returned each time a new row of data is ready for processing by the 4419** caller. The values may be accessed using the [column access functions]. 4420** sqlite3_step() is called again to retrieve the next row of data. 4421** 4422** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 4423** violation) has occurred. sqlite3_step() should not be called again on 4424** the VM. More information may be found by calling [sqlite3_errmsg()]. 4425** ^With the legacy interface, a more specific error code (for example, 4426** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 4427** can be obtained by calling [sqlite3_reset()] on the 4428** [prepared statement]. ^In the "v2" interface, 4429** the more specific error code is returned directly by sqlite3_step(). 4430** 4431** [SQLITE_MISUSE] means that the this routine was called inappropriately. 4432** Perhaps it was called on a [prepared statement] that has 4433** already been [sqlite3_finalize | finalized] or on one that had 4434** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 4435** be the case that the same database connection is being used by two or 4436** more threads at the same moment in time. 4437** 4438** For all versions of SQLite up to and including 3.6.23.1, a call to 4439** [sqlite3_reset()] was required after sqlite3_step() returned anything 4440** other than [SQLITE_ROW] before any subsequent invocation of 4441** sqlite3_step(). Failure to reset the prepared statement using 4442** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 4443** sqlite3_step(). But after [version 3.6.23.1] ([dateof:3.6.23.1], 4444** sqlite3_step() began 4445** calling [sqlite3_reset()] automatically in this circumstance rather 4446** than returning [SQLITE_MISUSE]. This is not considered a compatibility 4447** break because any application that ever receives an SQLITE_MISUSE error 4448** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 4449** can be used to restore the legacy behavior. 4450** 4451** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 4452** API always returns a generic error code, [SQLITE_ERROR], following any 4453** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 4454** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 4455** specific [error codes] that better describes the error. 4456** We admit that this is a goofy design. The problem has been fixed 4457** with the "v2" interface. If you prepare all of your SQL statements 4458** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()] 4459** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead 4460** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 4461** then the more specific [error codes] are returned directly 4462** by sqlite3_step(). The use of the "vX" interfaces is recommended. 4463*/ 4464int sqlite3_step(sqlite3_stmt*); 4465 4466/* 4467** CAPI3REF: Number of columns in a result set 4468** METHOD: sqlite3_stmt 4469** 4470** ^The sqlite3_data_count(P) interface returns the number of columns in the 4471** current row of the result set of [prepared statement] P. 4472** ^If prepared statement P does not have results ready to return 4473** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 4474** interfaces) then sqlite3_data_count(P) returns 0. 4475** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 4476** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 4477** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 4478** will return non-zero if previous call to [sqlite3_step](P) returned 4479** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 4480** where it always returns zero since each step of that multi-step 4481** pragma returns 0 columns of data. 4482** 4483** See also: [sqlite3_column_count()] 4484*/ 4485int sqlite3_data_count(sqlite3_stmt *pStmt); 4486 4487/* 4488** CAPI3REF: Fundamental Datatypes 4489** KEYWORDS: SQLITE_TEXT 4490** 4491** ^(Every value in SQLite has one of five fundamental datatypes: 4492** 4493** <ul> 4494** <li> 64-bit signed integer 4495** <li> 64-bit IEEE floating point number 4496** <li> string 4497** <li> BLOB 4498** <li> NULL 4499** </ul>)^ 4500** 4501** These constants are codes for each of those types. 4502** 4503** Note that the SQLITE_TEXT constant was also used in SQLite version 2 4504** for a completely different meaning. Software that links against both 4505** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 4506** SQLITE_TEXT. 4507*/ 4508#define SQLITE_INTEGER 1 4509#define SQLITE_FLOAT 2 4510#define SQLITE_BLOB 4 4511#define SQLITE_NULL 5 4512#ifdef SQLITE_TEXT 4513# undef SQLITE_TEXT 4514#else 4515# define SQLITE_TEXT 3 4516#endif 4517#define SQLITE3_TEXT 3 4518 4519/* 4520** CAPI3REF: Result Values From A Query 4521** KEYWORDS: {column access functions} 4522** METHOD: sqlite3_stmt 4523** 4524** <b>Summary:</b> 4525** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4526** <tr><td><b>sqlite3_column_blob</b><td>→<td>BLOB result 4527** <tr><td><b>sqlite3_column_double</b><td>→<td>REAL result 4528** <tr><td><b>sqlite3_column_int</b><td>→<td>32-bit INTEGER result 4529** <tr><td><b>sqlite3_column_int64</b><td>→<td>64-bit INTEGER result 4530** <tr><td><b>sqlite3_column_text</b><td>→<td>UTF-8 TEXT result 4531** <tr><td><b>sqlite3_column_text16</b><td>→<td>UTF-16 TEXT result 4532** <tr><td><b>sqlite3_column_value</b><td>→<td>The result as an 4533** [sqlite3_value|unprotected sqlite3_value] object. 4534** <tr><td> <td> <td> 4535** <tr><td><b>sqlite3_column_bytes</b><td>→<td>Size of a BLOB 4536** or a UTF-8 TEXT result in bytes 4537** <tr><td><b>sqlite3_column_bytes16 </b> 4538** <td>→ <td>Size of UTF-16 4539** TEXT in bytes 4540** <tr><td><b>sqlite3_column_type</b><td>→<td>Default 4541** datatype of the result 4542** </table></blockquote> 4543** 4544** <b>Details:</b> 4545** 4546** ^These routines return information about a single column of the current 4547** result row of a query. ^In every case the first argument is a pointer 4548** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 4549** that was returned from [sqlite3_prepare_v2()] or one of its variants) 4550** and the second argument is the index of the column for which information 4551** should be returned. ^The leftmost column of the result set has the index 0. 4552** ^The number of columns in the result can be determined using 4553** [sqlite3_column_count()]. 4554** 4555** If the SQL statement does not currently point to a valid row, or if the 4556** column index is out of range, the result is undefined. 4557** These routines may only be called when the most recent call to 4558** [sqlite3_step()] has returned [SQLITE_ROW] and neither 4559** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 4560** If any of these routines are called after [sqlite3_reset()] or 4561** [sqlite3_finalize()] or after [sqlite3_step()] has returned 4562** something other than [SQLITE_ROW], the results are undefined. 4563** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 4564** are called from a different thread while any of these routines 4565** are pending, then the results are undefined. 4566** 4567** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16) 4568** each return the value of a result column in a specific data format. If 4569** the result column is not initially in the requested format (for example, 4570** if the query returns an integer but the sqlite3_column_text() interface 4571** is used to extract the value) then an automatic type conversion is performed. 4572** 4573** ^The sqlite3_column_type() routine returns the 4574** [SQLITE_INTEGER | datatype code] for the initial data type 4575** of the result column. ^The returned value is one of [SQLITE_INTEGER], 4576** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. 4577** The return value of sqlite3_column_type() can be used to decide which 4578** of the first six interface should be used to extract the column value. 4579** The value returned by sqlite3_column_type() is only meaningful if no 4580** automatic type conversions have occurred for the value in question. 4581** After a type conversion, the result of calling sqlite3_column_type() 4582** is undefined, though harmless. Future 4583** versions of SQLite may change the behavior of sqlite3_column_type() 4584** following a type conversion. 4585** 4586** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes() 4587** or sqlite3_column_bytes16() interfaces can be used to determine the size 4588** of that BLOB or string. 4589** 4590** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 4591** routine returns the number of bytes in that BLOB or string. 4592** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 4593** the string to UTF-8 and then returns the number of bytes. 4594** ^If the result is a numeric value then sqlite3_column_bytes() uses 4595** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 4596** the number of bytes in that string. 4597** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 4598** 4599** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 4600** routine returns the number of bytes in that BLOB or string. 4601** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 4602** the string to UTF-16 and then returns the number of bytes. 4603** ^If the result is a numeric value then sqlite3_column_bytes16() uses 4604** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 4605** the number of bytes in that string. 4606** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 4607** 4608** ^The values returned by [sqlite3_column_bytes()] and 4609** [sqlite3_column_bytes16()] do not include the zero terminators at the end 4610** of the string. ^For clarity: the values returned by 4611** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 4612** bytes in the string, not the number of characters. 4613** 4614** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 4615** even empty strings, are always zero-terminated. ^The return 4616** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 4617** 4618** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an 4619** [unprotected sqlite3_value] object. In a multithreaded environment, 4620** an unprotected sqlite3_value object may only be used safely with 4621** [sqlite3_bind_value()] and [sqlite3_result_value()]. 4622** If the [unprotected sqlite3_value] object returned by 4623** [sqlite3_column_value()] is used in any other way, including calls 4624** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 4625** or [sqlite3_value_bytes()], the behavior is not threadsafe. 4626** Hence, the sqlite3_column_value() interface 4627** is normally only useful within the implementation of 4628** [application-defined SQL functions] or [virtual tables], not within 4629** top-level application code. 4630** 4631** The these routines may attempt to convert the datatype of the result. 4632** ^For example, if the internal representation is FLOAT and a text result 4633** is requested, [sqlite3_snprintf()] is used internally to perform the 4634** conversion automatically. ^(The following table details the conversions 4635** that are applied: 4636** 4637** <blockquote> 4638** <table border="1"> 4639** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 4640** 4641** <tr><td> NULL <td> INTEGER <td> Result is 0 4642** <tr><td> NULL <td> FLOAT <td> Result is 0.0 4643** <tr><td> NULL <td> TEXT <td> Result is a NULL pointer 4644** <tr><td> NULL <td> BLOB <td> Result is a NULL pointer 4645** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 4646** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 4647** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 4648** <tr><td> FLOAT <td> INTEGER <td> [CAST] to INTEGER 4649** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 4650** <tr><td> FLOAT <td> BLOB <td> [CAST] to BLOB 4651** <tr><td> TEXT <td> INTEGER <td> [CAST] to INTEGER 4652** <tr><td> TEXT <td> FLOAT <td> [CAST] to REAL 4653** <tr><td> TEXT <td> BLOB <td> No change 4654** <tr><td> BLOB <td> INTEGER <td> [CAST] to INTEGER 4655** <tr><td> BLOB <td> FLOAT <td> [CAST] to REAL 4656** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 4657** </table> 4658** </blockquote>)^ 4659** 4660** Note that when type conversions occur, pointers returned by prior 4661** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 4662** sqlite3_column_text16() may be invalidated. 4663** Type conversions and pointer invalidations might occur 4664** in the following cases: 4665** 4666** <ul> 4667** <li> The initial content is a BLOB and sqlite3_column_text() or 4668** sqlite3_column_text16() is called. A zero-terminator might 4669** need to be added to the string.</li> 4670** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 4671** sqlite3_column_text16() is called. The content must be converted 4672** to UTF-16.</li> 4673** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 4674** sqlite3_column_text() is called. The content must be converted 4675** to UTF-8.</li> 4676** </ul> 4677** 4678** ^Conversions between UTF-16be and UTF-16le are always done in place and do 4679** not invalidate a prior pointer, though of course the content of the buffer 4680** that the prior pointer references will have been modified. Other kinds 4681** of conversion are done in place when it is possible, but sometimes they 4682** are not possible and in those cases prior pointers are invalidated. 4683** 4684** The safest policy is to invoke these routines 4685** in one of the following ways: 4686** 4687** <ul> 4688** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 4689** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 4690** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 4691** </ul> 4692** 4693** In other words, you should call sqlite3_column_text(), 4694** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 4695** into the desired format, then invoke sqlite3_column_bytes() or 4696** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 4697** to sqlite3_column_text() or sqlite3_column_blob() with calls to 4698** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 4699** with calls to sqlite3_column_bytes(). 4700** 4701** ^The pointers returned are valid until a type conversion occurs as 4702** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 4703** [sqlite3_finalize()] is called. ^The memory space used to hold strings 4704** and BLOBs is freed automatically. Do not pass the pointers returned 4705** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 4706** [sqlite3_free()]. 4707** 4708** As long as the input parameters are correct, these routines will only 4709** fail if an out-of-memory error occurs during a format conversion. 4710** Only the following subset of interfaces are subject to out-of-memory 4711** errors: 4712** 4713** <ul> 4714** <li> sqlite3_column_blob() 4715** <li> sqlite3_column_text() 4716** <li> sqlite3_column_text16() 4717** <li> sqlite3_column_bytes() 4718** <li> sqlite3_column_bytes16() 4719** </ul> 4720** 4721** If an out-of-memory error occurs, then the return value from these 4722** routines is the same as if the column had contained an SQL NULL value. 4723** Valid SQL NULL returns can be distinguished from out-of-memory errors 4724** by invoking the [sqlite3_errcode()] immediately after the suspect 4725** return value is obtained and before any 4726** other SQLite interface is called on the same [database connection]. 4727*/ 4728const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 4729double sqlite3_column_double(sqlite3_stmt*, int iCol); 4730int sqlite3_column_int(sqlite3_stmt*, int iCol); 4731sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 4732const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 4733const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 4734sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 4735int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 4736int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 4737int sqlite3_column_type(sqlite3_stmt*, int iCol); 4738 4739/* 4740** CAPI3REF: Destroy A Prepared Statement Object 4741** DESTRUCTOR: sqlite3_stmt 4742** 4743** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 4744** ^If the most recent evaluation of the statement encountered no errors 4745** or if the statement is never been evaluated, then sqlite3_finalize() returns 4746** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 4747** sqlite3_finalize(S) returns the appropriate [error code] or 4748** [extended error code]. 4749** 4750** ^The sqlite3_finalize(S) routine can be called at any point during 4751** the life cycle of [prepared statement] S: 4752** before statement S is ever evaluated, after 4753** one or more calls to [sqlite3_reset()], or after any call 4754** to [sqlite3_step()] regardless of whether or not the statement has 4755** completed execution. 4756** 4757** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 4758** 4759** The application must finalize every [prepared statement] in order to avoid 4760** resource leaks. It is a grievous error for the application to try to use 4761** a prepared statement after it has been finalized. Any use of a prepared 4762** statement after it has been finalized can result in undefined and 4763** undesirable behavior such as segfaults and heap corruption. 4764*/ 4765int sqlite3_finalize(sqlite3_stmt *pStmt); 4766 4767/* 4768** CAPI3REF: Reset A Prepared Statement Object 4769** METHOD: sqlite3_stmt 4770** 4771** The sqlite3_reset() function is called to reset a [prepared statement] 4772** object back to its initial state, ready to be re-executed. 4773** ^Any SQL statement variables that had values bound to them using 4774** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 4775** Use [sqlite3_clear_bindings()] to reset the bindings. 4776** 4777** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 4778** back to the beginning of its program. 4779** 4780** ^If the most recent call to [sqlite3_step(S)] for the 4781** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 4782** or if [sqlite3_step(S)] has never before been called on S, 4783** then [sqlite3_reset(S)] returns [SQLITE_OK]. 4784** 4785** ^If the most recent call to [sqlite3_step(S)] for the 4786** [prepared statement] S indicated an error, then 4787** [sqlite3_reset(S)] returns an appropriate [error code]. 4788** 4789** ^The [sqlite3_reset(S)] interface does not change the values 4790** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 4791*/ 4792int sqlite3_reset(sqlite3_stmt *pStmt); 4793 4794/* 4795** CAPI3REF: Create Or Redefine SQL Functions 4796** KEYWORDS: {function creation routines} 4797** KEYWORDS: {application-defined SQL function} 4798** KEYWORDS: {application-defined SQL functions} 4799** METHOD: sqlite3 4800** 4801** ^These functions (collectively known as "function creation routines") 4802** are used to add SQL functions or aggregates or to redefine the behavior 4803** of existing SQL functions or aggregates. The only differences between 4804** the three "sqlite3_create_function*" routines are the text encoding 4805** expected for the second parameter (the name of the function being 4806** created) and the presence or absence of a destructor callback for 4807** the application data pointer. Function sqlite3_create_window_function() 4808** is similar, but allows the user to supply the extra callback functions 4809** needed by [aggregate window functions]. 4810** 4811** ^The first parameter is the [database connection] to which the SQL 4812** function is to be added. ^If an application uses more than one database 4813** connection then application-defined SQL functions must be added 4814** to each database connection separately. 4815** 4816** ^The second parameter is the name of the SQL function to be created or 4817** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 4818** representation, exclusive of the zero-terminator. ^Note that the name 4819** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 4820** ^Any attempt to create a function with a longer name 4821** will result in [SQLITE_MISUSE] being returned. 4822** 4823** ^The third parameter (nArg) 4824** is the number of arguments that the SQL function or 4825** aggregate takes. ^If this parameter is -1, then the SQL function or 4826** aggregate may take any number of arguments between 0 and the limit 4827** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 4828** parameter is less than -1 or greater than 127 then the behavior is 4829** undefined. 4830** 4831** ^The fourth parameter, eTextRep, specifies what 4832** [SQLITE_UTF8 | text encoding] this SQL function prefers for 4833** its parameters. The application should set this parameter to 4834** [SQLITE_UTF16LE] if the function implementation invokes 4835** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the 4836** implementation invokes [sqlite3_value_text16be()] on an input, or 4837** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8] 4838** otherwise. ^The same SQL function may be registered multiple times using 4839** different preferred text encodings, with different implementations for 4840** each encoding. 4841** ^When multiple implementations of the same function are available, SQLite 4842** will pick the one that involves the least amount of data conversion. 4843** 4844** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC] 4845** to signal that the function will always return the same result given 4846** the same inputs within a single SQL statement. Most SQL functions are 4847** deterministic. The built-in [random()] SQL function is an example of a 4848** function that is not deterministic. The SQLite query planner is able to 4849** perform additional optimizations on deterministic functions, so use 4850** of the [SQLITE_DETERMINISTIC] flag is recommended where possible. 4851** 4852** ^(The fifth parameter is an arbitrary pointer. The implementation of the 4853** function can gain access to this pointer using [sqlite3_user_data()].)^ 4854** 4855** ^The sixth, seventh and eighth parameters passed to the three 4856** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are 4857** pointers to C-language functions that implement the SQL function or 4858** aggregate. ^A scalar SQL function requires an implementation of the xFunc 4859** callback only; NULL pointers must be passed as the xStep and xFinal 4860** parameters. ^An aggregate SQL function requires an implementation of xStep 4861** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 4862** SQL function or aggregate, pass NULL pointers for all three function 4863** callbacks. 4864** 4865** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue 4866** and xInverse) passed to sqlite3_create_window_function are pointers to 4867** C-language callbacks that implement the new function. xStep and xFinal 4868** must both be non-NULL. xValue and xInverse may either both be NULL, in 4869** which case a regular aggregate function is created, or must both be 4870** non-NULL, in which case the new function may be used as either an aggregate 4871** or aggregate window function. More details regarding the implementation 4872** of aggregate window functions are 4873** [user-defined window functions|available here]. 4874** 4875** ^(If the final parameter to sqlite3_create_function_v2() or 4876** sqlite3_create_window_function() is not NULL, then it is destructor for 4877** the application data pointer. The destructor is invoked when the function 4878** is deleted, either by being overloaded or when the database connection 4879** closes.)^ ^The destructor is also invoked if the call to 4880** sqlite3_create_function_v2() fails. ^When the destructor callback is 4881** invoked, it is passed a single argument which is a copy of the application 4882** data pointer which was the fifth parameter to sqlite3_create_function_v2(). 4883** 4884** ^It is permitted to register multiple implementations of the same 4885** functions with the same name but with either differing numbers of 4886** arguments or differing preferred text encodings. ^SQLite will use 4887** the implementation that most closely matches the way in which the 4888** SQL function is used. ^A function implementation with a non-negative 4889** nArg parameter is a better match than a function implementation with 4890** a negative nArg. ^A function where the preferred text encoding 4891** matches the database encoding is a better 4892** match than a function where the encoding is different. 4893** ^A function where the encoding difference is between UTF16le and UTF16be 4894** is a closer match than a function where the encoding difference is 4895** between UTF8 and UTF16. 4896** 4897** ^Built-in functions may be overloaded by new application-defined functions. 4898** 4899** ^An application-defined function is permitted to call other 4900** SQLite interfaces. However, such calls must not 4901** close the database connection nor finalize or reset the prepared 4902** statement in which the function is running. 4903*/ 4904int sqlite3_create_function( 4905 sqlite3 *db, 4906 const char *zFunctionName, 4907 int nArg, 4908 int eTextRep, 4909 void *pApp, 4910 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4911 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4912 void (*xFinal)(sqlite3_context*) 4913); 4914int sqlite3_create_function16( 4915 sqlite3 *db, 4916 const void *zFunctionName, 4917 int nArg, 4918 int eTextRep, 4919 void *pApp, 4920 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4921 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4922 void (*xFinal)(sqlite3_context*) 4923); 4924int sqlite3_create_function_v2( 4925 sqlite3 *db, 4926 const char *zFunctionName, 4927 int nArg, 4928 int eTextRep, 4929 void *pApp, 4930 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 4931 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4932 void (*xFinal)(sqlite3_context*), 4933 void(*xDestroy)(void*) 4934); 4935int sqlite3_create_window_function( 4936 sqlite3 *db, 4937 const char *zFunctionName, 4938 int nArg, 4939 int eTextRep, 4940 void *pApp, 4941 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 4942 void (*xFinal)(sqlite3_context*), 4943 void (*xValue)(sqlite3_context*), 4944 void (*xInverse)(sqlite3_context*,int,sqlite3_value**), 4945 void(*xDestroy)(void*) 4946); 4947 4948/* 4949** CAPI3REF: Text Encodings 4950** 4951** These constant define integer codes that represent the various 4952** text encodings supported by SQLite. 4953*/ 4954#define SQLITE_UTF8 1 /* IMP: R-37514-35566 */ 4955#define SQLITE_UTF16LE 2 /* IMP: R-03371-37637 */ 4956#define SQLITE_UTF16BE 3 /* IMP: R-51971-34154 */ 4957#define SQLITE_UTF16 4 /* Use native byte order */ 4958#define SQLITE_ANY 5 /* Deprecated */ 4959#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 4960 4961/* 4962** CAPI3REF: Function Flags 4963** 4964** These constants may be ORed together with the 4965** [SQLITE_UTF8 | preferred text encoding] as the fourth argument 4966** to [sqlite3_create_function()], [sqlite3_create_function16()], or 4967** [sqlite3_create_function_v2()]. 4968*/ 4969#define SQLITE_DETERMINISTIC 0x800 4970 4971/* 4972** CAPI3REF: Deprecated Functions 4973** DEPRECATED 4974** 4975** These functions are [deprecated]. In order to maintain 4976** backwards compatibility with older code, these functions continue 4977** to be supported. However, new applications should avoid 4978** the use of these functions. To encourage programmers to avoid 4979** these functions, we will not explain what they do. 4980*/ 4981#ifndef SQLITE_OMIT_DEPRECATED 4982SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 4983SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 4984SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 4985SQLITE_DEPRECATED int sqlite3_global_recover(void); 4986SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 4987SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int), 4988 void*,sqlite3_int64); 4989#endif 4990 4991/* 4992** CAPI3REF: Obtaining SQL Values 4993** METHOD: sqlite3_value 4994** 4995** <b>Summary:</b> 4996** <blockquote><table border=0 cellpadding=0 cellspacing=0> 4997** <tr><td><b>sqlite3_value_blob</b><td>→<td>BLOB value 4998** <tr><td><b>sqlite3_value_double</b><td>→<td>REAL value 4999** <tr><td><b>sqlite3_value_int</b><td>→<td>32-bit INTEGER value 5000** <tr><td><b>sqlite3_value_int64</b><td>→<td>64-bit INTEGER value 5001** <tr><td><b>sqlite3_value_pointer</b><td>→<td>Pointer value 5002** <tr><td><b>sqlite3_value_text</b><td>→<td>UTF-8 TEXT value 5003** <tr><td><b>sqlite3_value_text16</b><td>→<td>UTF-16 TEXT value in 5004** the native byteorder 5005** <tr><td><b>sqlite3_value_text16be</b><td>→<td>UTF-16be TEXT value 5006** <tr><td><b>sqlite3_value_text16le</b><td>→<td>UTF-16le TEXT value 5007** <tr><td> <td> <td> 5008** <tr><td><b>sqlite3_value_bytes</b><td>→<td>Size of a BLOB 5009** or a UTF-8 TEXT in bytes 5010** <tr><td><b>sqlite3_value_bytes16 </b> 5011** <td>→ <td>Size of UTF-16 5012** TEXT in bytes 5013** <tr><td><b>sqlite3_value_type</b><td>→<td>Default 5014** datatype of the value 5015** <tr><td><b>sqlite3_value_numeric_type </b> 5016** <td>→ <td>Best numeric datatype of the value 5017** <tr><td><b>sqlite3_value_nochange </b> 5018** <td>→ <td>True if the column is unchanged in an UPDATE 5019** against a virtual table. 5020** <tr><td><b>sqlite3_value_frombind </b> 5021** <td>→ <td>True if value originated from a [bound parameter] 5022** </table></blockquote> 5023** 5024** <b>Details:</b> 5025** 5026** These routines extract type, size, and content information from 5027** [protected sqlite3_value] objects. Protected sqlite3_value objects 5028** are used to pass parameter information into implementation of 5029** [application-defined SQL functions] and [virtual tables]. 5030** 5031** These routines work only with [protected sqlite3_value] objects. 5032** Any attempt to use these routines on an [unprotected sqlite3_value] 5033** is not threadsafe. 5034** 5035** ^These routines work just like the corresponding [column access functions] 5036** except that these routines take a single [protected sqlite3_value] object 5037** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 5038** 5039** ^The sqlite3_value_text16() interface extracts a UTF-16 string 5040** in the native byte-order of the host machine. ^The 5041** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 5042** extract UTF-16 strings as big-endian and little-endian respectively. 5043** 5044** ^If [sqlite3_value] object V was initialized 5045** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)] 5046** and if X and Y are strings that compare equal according to strcmp(X,Y), 5047** then sqlite3_value_pointer(V,Y) will return the pointer P. ^Otherwise, 5048** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 5049** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5050** 5051** ^(The sqlite3_value_type(V) interface returns the 5052** [SQLITE_INTEGER | datatype code] for the initial datatype of the 5053** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER], 5054** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^ 5055** Other interfaces might change the datatype for an sqlite3_value object. 5056** For example, if the datatype is initially SQLITE_INTEGER and 5057** sqlite3_value_text(V) is called to extract a text value for that 5058** integer, then subsequent calls to sqlite3_value_type(V) might return 5059** SQLITE_TEXT. Whether or not a persistent internal datatype conversion 5060** occurs is undefined and may change from one release of SQLite to the next. 5061** 5062** ^(The sqlite3_value_numeric_type() interface attempts to apply 5063** numeric affinity to the value. This means that an attempt is 5064** made to convert the value to an integer or floating point. If 5065** such a conversion is possible without loss of information (in other 5066** words, if the value is a string that looks like a number) 5067** then the conversion is performed. Otherwise no conversion occurs. 5068** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 5069** 5070** ^Within the [xUpdate] method of a [virtual table], the 5071** sqlite3_value_nochange(X) interface returns true if and only if 5072** the column corresponding to X is unchanged by the UPDATE operation 5073** that the xUpdate method call was invoked to implement and if 5074** and the prior [xColumn] method call that was invoked to extracted 5075** the value for that column returned without setting a result (probably 5076** because it queried [sqlite3_vtab_nochange()] and found that the column 5077** was unchanging). ^Within an [xUpdate] method, any value for which 5078** sqlite3_value_nochange(X) is true will in all other respects appear 5079** to be a NULL value. If sqlite3_value_nochange(X) is invoked anywhere other 5080** than within an [xUpdate] method call for an UPDATE statement, then 5081** the return value is arbitrary and meaningless. 5082** 5083** ^The sqlite3_value_frombind(X) interface returns non-zero if the 5084** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()] 5085** interfaces. ^If X comes from an SQL literal value, or a table column, 5086** and expression, then sqlite3_value_frombind(X) returns zero. 5087** 5088** Please pay particular attention to the fact that the pointer returned 5089** from [sqlite3_value_blob()], [sqlite3_value_text()], or 5090** [sqlite3_value_text16()] can be invalidated by a subsequent call to 5091** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 5092** or [sqlite3_value_text16()]. 5093** 5094** These routines must be called from the same thread as 5095** the SQL function that supplied the [sqlite3_value*] parameters. 5096** 5097** As long as the input parameter is correct, these routines can only 5098** fail if an out-of-memory error occurs during a format conversion. 5099** Only the following subset of interfaces are subject to out-of-memory 5100** errors: 5101** 5102** <ul> 5103** <li> sqlite3_value_blob() 5104** <li> sqlite3_value_text() 5105** <li> sqlite3_value_text16() 5106** <li> sqlite3_value_text16le() 5107** <li> sqlite3_value_text16be() 5108** <li> sqlite3_value_bytes() 5109** <li> sqlite3_value_bytes16() 5110** </ul> 5111** 5112** If an out-of-memory error occurs, then the return value from these 5113** routines is the same as if the column had contained an SQL NULL value. 5114** Valid SQL NULL returns can be distinguished from out-of-memory errors 5115** by invoking the [sqlite3_errcode()] immediately after the suspect 5116** return value is obtained and before any 5117** other SQLite interface is called on the same [database connection]. 5118*/ 5119const void *sqlite3_value_blob(sqlite3_value*); 5120double sqlite3_value_double(sqlite3_value*); 5121int sqlite3_value_int(sqlite3_value*); 5122sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 5123void *sqlite3_value_pointer(sqlite3_value*, const char*); 5124const unsigned char *sqlite3_value_text(sqlite3_value*); 5125const void *sqlite3_value_text16(sqlite3_value*); 5126const void *sqlite3_value_text16le(sqlite3_value*); 5127const void *sqlite3_value_text16be(sqlite3_value*); 5128int sqlite3_value_bytes(sqlite3_value*); 5129int sqlite3_value_bytes16(sqlite3_value*); 5130int sqlite3_value_type(sqlite3_value*); 5131int sqlite3_value_numeric_type(sqlite3_value*); 5132int sqlite3_value_nochange(sqlite3_value*); 5133int sqlite3_value_frombind(sqlite3_value*); 5134 5135/* 5136** CAPI3REF: Finding The Subtype Of SQL Values 5137** METHOD: sqlite3_value 5138** 5139** The sqlite3_value_subtype(V) function returns the subtype for 5140** an [application-defined SQL function] argument V. The subtype 5141** information can be used to pass a limited amount of context from 5142** one SQL function to another. Use the [sqlite3_result_subtype()] 5143** routine to set the subtype for the return value of an SQL function. 5144*/ 5145unsigned int sqlite3_value_subtype(sqlite3_value*); 5146 5147/* 5148** CAPI3REF: Copy And Free SQL Values 5149** METHOD: sqlite3_value 5150** 5151** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value] 5152** object D and returns a pointer to that copy. ^The [sqlite3_value] returned 5153** is a [protected sqlite3_value] object even if the input is not. 5154** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a 5155** memory allocation fails. 5156** 5157** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object 5158** previously obtained from [sqlite3_value_dup()]. ^If V is a NULL pointer 5159** then sqlite3_value_free(V) is a harmless no-op. 5160*/ 5161sqlite3_value *sqlite3_value_dup(const sqlite3_value*); 5162void sqlite3_value_free(sqlite3_value*); 5163 5164/* 5165** CAPI3REF: Obtain Aggregate Function Context 5166** METHOD: sqlite3_context 5167** 5168** Implementations of aggregate SQL functions use this 5169** routine to allocate memory for storing their state. 5170** 5171** ^The first time the sqlite3_aggregate_context(C,N) routine is called 5172** for a particular aggregate function, SQLite 5173** allocates N of memory, zeroes out that memory, and returns a pointer 5174** to the new memory. ^On second and subsequent calls to 5175** sqlite3_aggregate_context() for the same aggregate function instance, 5176** the same buffer is returned. Sqlite3_aggregate_context() is normally 5177** called once for each invocation of the xStep callback and then one 5178** last time when the xFinal callback is invoked. ^(When no rows match 5179** an aggregate query, the xStep() callback of the aggregate function 5180** implementation is never called and xFinal() is called exactly once. 5181** In those cases, sqlite3_aggregate_context() might be called for the 5182** first time from within xFinal().)^ 5183** 5184** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 5185** when first called if N is less than or equal to zero or if a memory 5186** allocate error occurs. 5187** 5188** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 5189** determined by the N parameter on first successful call. Changing the 5190** value of N in subsequent call to sqlite3_aggregate_context() within 5191** the same aggregate function instance will not resize the memory 5192** allocation.)^ Within the xFinal callback, it is customary to set 5193** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 5194** pointless memory allocations occur. 5195** 5196** ^SQLite automatically frees the memory allocated by 5197** sqlite3_aggregate_context() when the aggregate query concludes. 5198** 5199** The first parameter must be a copy of the 5200** [sqlite3_context | SQL function context] that is the first parameter 5201** to the xStep or xFinal callback routine that implements the aggregate 5202** function. 5203** 5204** This routine must be called from the same thread in which 5205** the aggregate SQL function is running. 5206*/ 5207void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 5208 5209/* 5210** CAPI3REF: User Data For Functions 5211** METHOD: sqlite3_context 5212** 5213** ^The sqlite3_user_data() interface returns a copy of 5214** the pointer that was the pUserData parameter (the 5th parameter) 5215** of the [sqlite3_create_function()] 5216** and [sqlite3_create_function16()] routines that originally 5217** registered the application defined function. 5218** 5219** This routine must be called from the same thread in which 5220** the application-defined function is running. 5221*/ 5222void *sqlite3_user_data(sqlite3_context*); 5223 5224/* 5225** CAPI3REF: Database Connection For Functions 5226** METHOD: sqlite3_context 5227** 5228** ^The sqlite3_context_db_handle() interface returns a copy of 5229** the pointer to the [database connection] (the 1st parameter) 5230** of the [sqlite3_create_function()] 5231** and [sqlite3_create_function16()] routines that originally 5232** registered the application defined function. 5233*/ 5234sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 5235 5236/* 5237** CAPI3REF: Function Auxiliary Data 5238** METHOD: sqlite3_context 5239** 5240** These functions may be used by (non-aggregate) SQL functions to 5241** associate metadata with argument values. If the same value is passed to 5242** multiple invocations of the same SQL function during query execution, under 5243** some circumstances the associated metadata may be preserved. An example 5244** of where this might be useful is in a regular-expression matching 5245** function. The compiled version of the regular expression can be stored as 5246** metadata associated with the pattern string. 5247** Then as long as the pattern string remains the same, 5248** the compiled regular expression can be reused on multiple 5249** invocations of the same function. 5250** 5251** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata 5252** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument 5253** value to the application-defined function. ^N is zero for the left-most 5254** function argument. ^If there is no metadata 5255** associated with the function argument, the sqlite3_get_auxdata(C,N) interface 5256** returns a NULL pointer. 5257** 5258** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th 5259** argument of the application-defined function. ^Subsequent 5260** calls to sqlite3_get_auxdata(C,N) return P from the most recent 5261** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or 5262** NULL if the metadata has been discarded. 5263** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL, 5264** SQLite will invoke the destructor function X with parameter P exactly 5265** once, when the metadata is discarded. 5266** SQLite is free to discard the metadata at any time, including: <ul> 5267** <li> ^(when the corresponding function parameter changes)^, or 5268** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the 5269** SQL statement)^, or 5270** <li> ^(when sqlite3_set_auxdata() is invoked again on the same 5271** parameter)^, or 5272** <li> ^(during the original sqlite3_set_auxdata() call when a memory 5273** allocation error occurs.)^ </ul> 5274** 5275** Note the last bullet in particular. The destructor X in 5276** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the 5277** sqlite3_set_auxdata() interface even returns. Hence sqlite3_set_auxdata() 5278** should be called near the end of the function implementation and the 5279** function implementation should not make any use of P after 5280** sqlite3_set_auxdata() has been called. 5281** 5282** ^(In practice, metadata is preserved between function calls for 5283** function parameters that are compile-time constants, including literal 5284** values and [parameters] and expressions composed from the same.)^ 5285** 5286** The value of the N parameter to these interfaces should be non-negative. 5287** Future enhancements may make use of negative N values to define new 5288** kinds of function caching behavior. 5289** 5290** These routines must be called from the same thread in which 5291** the SQL function is running. 5292*/ 5293void *sqlite3_get_auxdata(sqlite3_context*, int N); 5294void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 5295 5296 5297/* 5298** CAPI3REF: Constants Defining Special Destructor Behavior 5299** 5300** These are special values for the destructor that is passed in as the 5301** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 5302** argument is SQLITE_STATIC, it means that the content pointer is constant 5303** and will never change. It does not need to be destroyed. ^The 5304** SQLITE_TRANSIENT value means that the content will likely change in 5305** the near future and that SQLite should make its own private copy of 5306** the content before returning. 5307** 5308** The typedef is necessary to work around problems in certain 5309** C++ compilers. 5310*/ 5311typedef void (*sqlite3_destructor_type)(void*); 5312#define SQLITE_STATIC ((sqlite3_destructor_type)0) 5313#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 5314 5315/* 5316** CAPI3REF: Setting The Result Of An SQL Function 5317** METHOD: sqlite3_context 5318** 5319** These routines are used by the xFunc or xFinal callbacks that 5320** implement SQL functions and aggregates. See 5321** [sqlite3_create_function()] and [sqlite3_create_function16()] 5322** for additional information. 5323** 5324** These functions work very much like the [parameter binding] family of 5325** functions used to bind values to host parameters in prepared statements. 5326** Refer to the [SQL parameter] documentation for additional information. 5327** 5328** ^The sqlite3_result_blob() interface sets the result from 5329** an application-defined function to be the BLOB whose content is pointed 5330** to by the second parameter and which is N bytes long where N is the 5331** third parameter. 5332** 5333** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N) 5334** interfaces set the result of the application-defined function to be 5335** a BLOB containing all zero bytes and N bytes in size. 5336** 5337** ^The sqlite3_result_double() interface sets the result from 5338** an application-defined function to be a floating point value specified 5339** by its 2nd argument. 5340** 5341** ^The sqlite3_result_error() and sqlite3_result_error16() functions 5342** cause the implemented SQL function to throw an exception. 5343** ^SQLite uses the string pointed to by the 5344** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 5345** as the text of an error message. ^SQLite interprets the error 5346** message string from sqlite3_result_error() as UTF-8. ^SQLite 5347** interprets the string from sqlite3_result_error16() as UTF-16 in native 5348** byte order. ^If the third parameter to sqlite3_result_error() 5349** or sqlite3_result_error16() is negative then SQLite takes as the error 5350** message all text up through the first zero character. 5351** ^If the third parameter to sqlite3_result_error() or 5352** sqlite3_result_error16() is non-negative then SQLite takes that many 5353** bytes (not characters) from the 2nd parameter as the error message. 5354** ^The sqlite3_result_error() and sqlite3_result_error16() 5355** routines make a private copy of the error message text before 5356** they return. Hence, the calling function can deallocate or 5357** modify the text after they return without harm. 5358** ^The sqlite3_result_error_code() function changes the error code 5359** returned by SQLite as a result of an error in a function. ^By default, 5360** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 5361** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 5362** 5363** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an 5364** error indicating that a string or BLOB is too long to represent. 5365** 5366** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an 5367** error indicating that a memory allocation failed. 5368** 5369** ^The sqlite3_result_int() interface sets the return value 5370** of the application-defined function to be the 32-bit signed integer 5371** value given in the 2nd argument. 5372** ^The sqlite3_result_int64() interface sets the return value 5373** of the application-defined function to be the 64-bit signed integer 5374** value given in the 2nd argument. 5375** 5376** ^The sqlite3_result_null() interface sets the return value 5377** of the application-defined function to be NULL. 5378** 5379** ^The sqlite3_result_text(), sqlite3_result_text16(), 5380** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 5381** set the return value of the application-defined function to be 5382** a text string which is represented as UTF-8, UTF-16 native byte order, 5383** UTF-16 little endian, or UTF-16 big endian, respectively. 5384** ^The sqlite3_result_text64() interface sets the return value of an 5385** application-defined function to be a text string in an encoding 5386** specified by the fifth (and last) parameter, which must be one 5387** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]. 5388** ^SQLite takes the text result from the application from 5389** the 2nd parameter of the sqlite3_result_text* interfaces. 5390** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5391** is negative, then SQLite takes result text from the 2nd parameter 5392** through the first zero character. 5393** ^If the 3rd parameter to the sqlite3_result_text* interfaces 5394** is non-negative, then as many bytes (not characters) of the text 5395** pointed to by the 2nd parameter are taken as the application-defined 5396** function result. If the 3rd parameter is non-negative, then it 5397** must be the byte offset into the string where the NUL terminator would 5398** appear if the string where NUL terminated. If any NUL characters occur 5399** in the string at a byte offset that is less than the value of the 3rd 5400** parameter, then the resulting string will contain embedded NULs and the 5401** result of expressions operating on strings with embedded NULs is undefined. 5402** ^If the 4th parameter to the sqlite3_result_text* interfaces 5403** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 5404** function as the destructor on the text or BLOB result when it has 5405** finished using that result. 5406** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 5407** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 5408** assumes that the text or BLOB result is in constant space and does not 5409** copy the content of the parameter nor call a destructor on the content 5410** when it has finished using that result. 5411** ^If the 4th parameter to the sqlite3_result_text* interfaces 5412** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 5413** then SQLite makes a copy of the result into space obtained 5414** from [sqlite3_malloc()] before it returns. 5415** 5416** ^The sqlite3_result_value() interface sets the result of 5417** the application-defined function to be a copy of the 5418** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 5419** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 5420** so that the [sqlite3_value] specified in the parameter may change or 5421** be deallocated after sqlite3_result_value() returns without harm. 5422** ^A [protected sqlite3_value] object may always be used where an 5423** [unprotected sqlite3_value] object is required, so either 5424** kind of [sqlite3_value] object can be used with this interface. 5425** 5426** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an 5427** SQL NULL value, just like [sqlite3_result_null(C)], except that it 5428** also associates the host-language pointer P or type T with that 5429** NULL value such that the pointer can be retrieved within an 5430** [application-defined SQL function] using [sqlite3_value_pointer()]. 5431** ^If the D parameter is not NULL, then it is a pointer to a destructor 5432** for the P parameter. ^SQLite invokes D with P as its only argument 5433** when SQLite is finished with P. The T parameter should be a static 5434** string and preferably a string literal. The sqlite3_result_pointer() 5435** routine is part of the [pointer passing interface] added for SQLite 3.20.0. 5436** 5437** If these routines are called from within the different thread 5438** than the one containing the application-defined function that received 5439** the [sqlite3_context] pointer, the results are undefined. 5440*/ 5441void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 5442void sqlite3_result_blob64(sqlite3_context*,const void*, 5443 sqlite3_uint64,void(*)(void*)); 5444void sqlite3_result_double(sqlite3_context*, double); 5445void sqlite3_result_error(sqlite3_context*, const char*, int); 5446void sqlite3_result_error16(sqlite3_context*, const void*, int); 5447void sqlite3_result_error_toobig(sqlite3_context*); 5448void sqlite3_result_error_nomem(sqlite3_context*); 5449void sqlite3_result_error_code(sqlite3_context*, int); 5450void sqlite3_result_int(sqlite3_context*, int); 5451void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 5452void sqlite3_result_null(sqlite3_context*); 5453void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 5454void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64, 5455 void(*)(void*), unsigned char encoding); 5456void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 5457void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 5458void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 5459void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 5460void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*)); 5461void sqlite3_result_zeroblob(sqlite3_context*, int n); 5462int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n); 5463 5464 5465/* 5466** CAPI3REF: Setting The Subtype Of An SQL Function 5467** METHOD: sqlite3_context 5468** 5469** The sqlite3_result_subtype(C,T) function causes the subtype of 5470** the result from the [application-defined SQL function] with 5471** [sqlite3_context] C to be the value T. Only the lower 8 bits 5472** of the subtype T are preserved in current versions of SQLite; 5473** higher order bits are discarded. 5474** The number of subtype bytes preserved by SQLite might increase 5475** in future releases of SQLite. 5476*/ 5477void sqlite3_result_subtype(sqlite3_context*,unsigned int); 5478 5479/* 5480** CAPI3REF: Define New Collating Sequences 5481** METHOD: sqlite3 5482** 5483** ^These functions add, remove, or modify a [collation] associated 5484** with the [database connection] specified as the first argument. 5485** 5486** ^The name of the collation is a UTF-8 string 5487** for sqlite3_create_collation() and sqlite3_create_collation_v2() 5488** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 5489** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 5490** considered to be the same name. 5491** 5492** ^(The third argument (eTextRep) must be one of the constants: 5493** <ul> 5494** <li> [SQLITE_UTF8], 5495** <li> [SQLITE_UTF16LE], 5496** <li> [SQLITE_UTF16BE], 5497** <li> [SQLITE_UTF16], or 5498** <li> [SQLITE_UTF16_ALIGNED]. 5499** </ul>)^ 5500** ^The eTextRep argument determines the encoding of strings passed 5501** to the collating function callback, xCallback. 5502** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 5503** force strings to be UTF16 with native byte order. 5504** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 5505** on an even byte address. 5506** 5507** ^The fourth argument, pArg, is an application data pointer that is passed 5508** through as the first argument to the collating function callback. 5509** 5510** ^The fifth argument, xCallback, is a pointer to the collating function. 5511** ^Multiple collating functions can be registered using the same name but 5512** with different eTextRep parameters and SQLite will use whichever 5513** function requires the least amount of data transformation. 5514** ^If the xCallback argument is NULL then the collating function is 5515** deleted. ^When all collating functions having the same name are deleted, 5516** that collation is no longer usable. 5517** 5518** ^The collating function callback is invoked with a copy of the pArg 5519** application data pointer and with two strings in the encoding specified 5520** by the eTextRep argument. The collating function must return an 5521** integer that is negative, zero, or positive 5522** if the first string is less than, equal to, or greater than the second, 5523** respectively. A collating function must always return the same answer 5524** given the same inputs. If two or more collating functions are registered 5525** to the same collation name (using different eTextRep values) then all 5526** must give an equivalent answer when invoked with equivalent strings. 5527** The collating function must obey the following properties for all 5528** strings A, B, and C: 5529** 5530** <ol> 5531** <li> If A==B then B==A. 5532** <li> If A==B and B==C then A==C. 5533** <li> If A<B THEN B>A. 5534** <li> If A<B and B<C then A<C. 5535** </ol> 5536** 5537** If a collating function fails any of the above constraints and that 5538** collating function is registered and used, then the behavior of SQLite 5539** is undefined. 5540** 5541** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 5542** with the addition that the xDestroy callback is invoked on pArg when 5543** the collating function is deleted. 5544** ^Collating functions are deleted when they are overridden by later 5545** calls to the collation creation functions or when the 5546** [database connection] is closed using [sqlite3_close()]. 5547** 5548** ^The xDestroy callback is <u>not</u> called if the 5549** sqlite3_create_collation_v2() function fails. Applications that invoke 5550** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 5551** check the return code and dispose of the application data pointer 5552** themselves rather than expecting SQLite to deal with it for them. 5553** This is different from every other SQLite interface. The inconsistency 5554** is unfortunate but cannot be changed without breaking backwards 5555** compatibility. 5556** 5557** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 5558*/ 5559int sqlite3_create_collation( 5560 sqlite3*, 5561 const char *zName, 5562 int eTextRep, 5563 void *pArg, 5564 int(*xCompare)(void*,int,const void*,int,const void*) 5565); 5566int sqlite3_create_collation_v2( 5567 sqlite3*, 5568 const char *zName, 5569 int eTextRep, 5570 void *pArg, 5571 int(*xCompare)(void*,int,const void*,int,const void*), 5572 void(*xDestroy)(void*) 5573); 5574int sqlite3_create_collation16( 5575 sqlite3*, 5576 const void *zName, 5577 int eTextRep, 5578 void *pArg, 5579 int(*xCompare)(void*,int,const void*,int,const void*) 5580); 5581 5582/* 5583** CAPI3REF: Collation Needed Callbacks 5584** METHOD: sqlite3 5585** 5586** ^To avoid having to register all collation sequences before a database 5587** can be used, a single callback function may be registered with the 5588** [database connection] to be invoked whenever an undefined collation 5589** sequence is required. 5590** 5591** ^If the function is registered using the sqlite3_collation_needed() API, 5592** then it is passed the names of undefined collation sequences as strings 5593** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 5594** the names are passed as UTF-16 in machine native byte order. 5595** ^A call to either function replaces the existing collation-needed callback. 5596** 5597** ^(When the callback is invoked, the first argument passed is a copy 5598** of the second argument to sqlite3_collation_needed() or 5599** sqlite3_collation_needed16(). The second argument is the database 5600** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 5601** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 5602** sequence function required. The fourth parameter is the name of the 5603** required collation sequence.)^ 5604** 5605** The callback function should register the desired collation using 5606** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 5607** [sqlite3_create_collation_v2()]. 5608*/ 5609int sqlite3_collation_needed( 5610 sqlite3*, 5611 void*, 5612 void(*)(void*,sqlite3*,int eTextRep,const char*) 5613); 5614int sqlite3_collation_needed16( 5615 sqlite3*, 5616 void*, 5617 void(*)(void*,sqlite3*,int eTextRep,const void*) 5618); 5619 5620#ifdef SQLITE_HAS_CODEC 5621/* 5622** Specify the key for an encrypted database. This routine should be 5623** called right after sqlite3_open(). 5624** 5625** The code to implement this API is not available in the public release 5626** of SQLite. 5627*/ 5628int sqlite3_key( 5629 sqlite3 *db, /* Database to be rekeyed */ 5630 const void *pKey, int nKey /* The key */ 5631); 5632int sqlite3_key_v2( 5633 sqlite3 *db, /* Database to be rekeyed */ 5634 const char *zDbName, /* Name of the database */ 5635 const void *pKey, int nKey /* The key */ 5636); 5637 5638/* 5639** Change the key on an open database. If the current database is not 5640** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 5641** database is decrypted. 5642** 5643** The code to implement this API is not available in the public release 5644** of SQLite. 5645*/ 5646int sqlite3_rekey( 5647 sqlite3 *db, /* Database to be rekeyed */ 5648 const void *pKey, int nKey /* The new key */ 5649); 5650int sqlite3_rekey_v2( 5651 sqlite3 *db, /* Database to be rekeyed */ 5652 const char *zDbName, /* Name of the database */ 5653 const void *pKey, int nKey /* The new key */ 5654); 5655 5656/* 5657** Specify the activation key for a SEE database. Unless 5658** activated, none of the SEE routines will work. 5659*/ 5660void sqlite3_activate_see( 5661 const char *zPassPhrase /* Activation phrase */ 5662); 5663#endif 5664 5665#ifdef SQLITE_ENABLE_CEROD 5666/* 5667** Specify the activation key for a CEROD database. Unless 5668** activated, none of the CEROD routines will work. 5669*/ 5670void sqlite3_activate_cerod( 5671 const char *zPassPhrase /* Activation phrase */ 5672); 5673#endif 5674 5675/* 5676** CAPI3REF: Suspend Execution For A Short Time 5677** 5678** The sqlite3_sleep() function causes the current thread to suspend execution 5679** for at least a number of milliseconds specified in its parameter. 5680** 5681** If the operating system does not support sleep requests with 5682** millisecond time resolution, then the time will be rounded up to 5683** the nearest second. The number of milliseconds of sleep actually 5684** requested from the operating system is returned. 5685** 5686** ^SQLite implements this interface by calling the xSleep() 5687** method of the default [sqlite3_vfs] object. If the xSleep() method 5688** of the default VFS is not implemented correctly, or not implemented at 5689** all, then the behavior of sqlite3_sleep() may deviate from the description 5690** in the previous paragraphs. 5691*/ 5692int sqlite3_sleep(int); 5693 5694/* 5695** CAPI3REF: Name Of The Folder Holding Temporary Files 5696** 5697** ^(If this global variable is made to point to a string which is 5698** the name of a folder (a.k.a. directory), then all temporary files 5699** created by SQLite when using a built-in [sqlite3_vfs | VFS] 5700** will be placed in that directory.)^ ^If this variable 5701** is a NULL pointer, then SQLite performs a search for an appropriate 5702** temporary file directory. 5703** 5704** Applications are strongly discouraged from using this global variable. 5705** It is required to set a temporary folder on Windows Runtime (WinRT). 5706** But for all other platforms, it is highly recommended that applications 5707** neither read nor write this variable. This global variable is a relic 5708** that exists for backwards compatibility of legacy applications and should 5709** be avoided in new projects. 5710** 5711** It is not safe to read or modify this variable in more than one 5712** thread at a time. It is not safe to read or modify this variable 5713** if a [database connection] is being used at the same time in a separate 5714** thread. 5715** It is intended that this variable be set once 5716** as part of process initialization and before any SQLite interface 5717** routines have been called and that this variable remain unchanged 5718** thereafter. 5719** 5720** ^The [temp_store_directory pragma] may modify this variable and cause 5721** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5722** the [temp_store_directory pragma] always assumes that any string 5723** that this variable points to is held in memory obtained from 5724** [sqlite3_malloc] and the pragma may attempt to free that memory 5725** using [sqlite3_free]. 5726** Hence, if this variable is modified directly, either it should be 5727** made NULL or made to point to memory obtained from [sqlite3_malloc] 5728** or else the use of the [temp_store_directory pragma] should be avoided. 5729** Except when requested by the [temp_store_directory pragma], SQLite 5730** does not free the memory that sqlite3_temp_directory points to. If 5731** the application wants that memory to be freed, it must do 5732** so itself, taking care to only do so after all [database connection] 5733** objects have been destroyed. 5734** 5735** <b>Note to Windows Runtime users:</b> The temporary directory must be set 5736** prior to calling [sqlite3_open] or [sqlite3_open_v2]. Otherwise, various 5737** features that require the use of temporary files may fail. Here is an 5738** example of how to do this using C++ with the Windows Runtime: 5739** 5740** <blockquote><pre> 5741** LPCWSTR zPath = Windows::Storage::ApplicationData::Current-> 5742** TemporaryFolder->Path->Data(); 5743** char zPathBuf[MAX_PATH + 1]; 5744** memset(zPathBuf, 0, sizeof(zPathBuf)); 5745** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf), 5746** NULL, NULL); 5747** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf); 5748** </pre></blockquote> 5749*/ 5750SQLITE_EXTERN char *sqlite3_temp_directory; 5751 5752/* 5753** CAPI3REF: Name Of The Folder Holding Database Files 5754** 5755** ^(If this global variable is made to point to a string which is 5756** the name of a folder (a.k.a. directory), then all database files 5757** specified with a relative pathname and created or accessed by 5758** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed 5759** to be relative to that directory.)^ ^If this variable is a NULL 5760** pointer, then SQLite assumes that all database files specified 5761** with a relative pathname are relative to the current directory 5762** for the process. Only the windows VFS makes use of this global 5763** variable; it is ignored by the unix VFS. 5764** 5765** Changing the value of this variable while a database connection is 5766** open can result in a corrupt database. 5767** 5768** It is not safe to read or modify this variable in more than one 5769** thread at a time. It is not safe to read or modify this variable 5770** if a [database connection] is being used at the same time in a separate 5771** thread. 5772** It is intended that this variable be set once 5773** as part of process initialization and before any SQLite interface 5774** routines have been called and that this variable remain unchanged 5775** thereafter. 5776** 5777** ^The [data_store_directory pragma] may modify this variable and cause 5778** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 5779** the [data_store_directory pragma] always assumes that any string 5780** that this variable points to is held in memory obtained from 5781** [sqlite3_malloc] and the pragma may attempt to free that memory 5782** using [sqlite3_free]. 5783** Hence, if this variable is modified directly, either it should be 5784** made NULL or made to point to memory obtained from [sqlite3_malloc] 5785** or else the use of the [data_store_directory pragma] should be avoided. 5786*/ 5787SQLITE_EXTERN char *sqlite3_data_directory; 5788 5789/* 5790** CAPI3REF: Win32 Specific Interface 5791** 5792** These interfaces are available only on Windows. The 5793** [sqlite3_win32_set_directory] interface is used to set the value associated 5794** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to 5795** zValue, depending on the value of the type parameter. The zValue parameter 5796** should be NULL to cause the previous value to be freed via [sqlite3_free]; 5797** a non-NULL value will be copied into memory obtained from [sqlite3_malloc] 5798** prior to being used. The [sqlite3_win32_set_directory] interface returns 5799** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported, 5800** or [SQLITE_NOMEM] if memory could not be allocated. The value of the 5801** [sqlite3_data_directory] variable is intended to act as a replacement for 5802** the current directory on the sub-platforms of Win32 where that concept is 5803** not present, e.g. WinRT and UWP. The [sqlite3_win32_set_directory8] and 5804** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the 5805** sqlite3_win32_set_directory interface except the string parameter must be 5806** UTF-8 or UTF-16, respectively. 5807*/ 5808int sqlite3_win32_set_directory( 5809 unsigned long type, /* Identifier for directory being set or reset */ 5810 void *zValue /* New value for directory being set or reset */ 5811); 5812int sqlite3_win32_set_directory8(unsigned long type, const char *zValue); 5813int sqlite3_win32_set_directory16(unsigned long type, const void *zValue); 5814 5815/* 5816** CAPI3REF: Win32 Directory Types 5817** 5818** These macros are only available on Windows. They define the allowed values 5819** for the type argument to the [sqlite3_win32_set_directory] interface. 5820*/ 5821#define SQLITE_WIN32_DATA_DIRECTORY_TYPE 1 5822#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE 2 5823 5824/* 5825** CAPI3REF: Test For Auto-Commit Mode 5826** KEYWORDS: {autocommit mode} 5827** METHOD: sqlite3 5828** 5829** ^The sqlite3_get_autocommit() interface returns non-zero or 5830** zero if the given database connection is or is not in autocommit mode, 5831** respectively. ^Autocommit mode is on by default. 5832** ^Autocommit mode is disabled by a [BEGIN] statement. 5833** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 5834** 5835** If certain kinds of errors occur on a statement within a multi-statement 5836** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 5837** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 5838** transaction might be rolled back automatically. The only way to 5839** find out whether SQLite automatically rolled back the transaction after 5840** an error is to use this function. 5841** 5842** If another thread changes the autocommit status of the database 5843** connection while this routine is running, then the return value 5844** is undefined. 5845*/ 5846int sqlite3_get_autocommit(sqlite3*); 5847 5848/* 5849** CAPI3REF: Find The Database Handle Of A Prepared Statement 5850** METHOD: sqlite3_stmt 5851** 5852** ^The sqlite3_db_handle interface returns the [database connection] handle 5853** to which a [prepared statement] belongs. ^The [database connection] 5854** returned by sqlite3_db_handle is the same [database connection] 5855** that was the first argument 5856** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 5857** create the statement in the first place. 5858*/ 5859sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 5860 5861/* 5862** CAPI3REF: Return The Filename For A Database Connection 5863** METHOD: sqlite3 5864** 5865** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 5866** associated with database N of connection D. ^The main database file 5867** has the name "main". If there is no attached database N on the database 5868** connection D, or if database N is a temporary or in-memory database, then 5869** this function will return either a NULL pointer or an empty string. 5870** 5871** ^The filename returned by this function is the output of the 5872** xFullPathname method of the [VFS]. ^In other words, the filename 5873** will be an absolute pathname, even if the filename used 5874** to open the database originally was a URI or relative pathname. 5875*/ 5876const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 5877 5878/* 5879** CAPI3REF: Determine if a database is read-only 5880** METHOD: sqlite3 5881** 5882** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 5883** of connection D is read-only, 0 if it is read/write, or -1 if N is not 5884** the name of a database on connection D. 5885*/ 5886int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 5887 5888/* 5889** CAPI3REF: Find the next prepared statement 5890** METHOD: sqlite3 5891** 5892** ^This interface returns a pointer to the next [prepared statement] after 5893** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 5894** then this interface returns a pointer to the first prepared statement 5895** associated with the database connection pDb. ^If no prepared statement 5896** satisfies the conditions of this routine, it returns NULL. 5897** 5898** The [database connection] pointer D in a call to 5899** [sqlite3_next_stmt(D,S)] must refer to an open database 5900** connection and in particular must not be a NULL pointer. 5901*/ 5902sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 5903 5904/* 5905** CAPI3REF: Commit And Rollback Notification Callbacks 5906** METHOD: sqlite3 5907** 5908** ^The sqlite3_commit_hook() interface registers a callback 5909** function to be invoked whenever a transaction is [COMMIT | committed]. 5910** ^Any callback set by a previous call to sqlite3_commit_hook() 5911** for the same database connection is overridden. 5912** ^The sqlite3_rollback_hook() interface registers a callback 5913** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 5914** ^Any callback set by a previous call to sqlite3_rollback_hook() 5915** for the same database connection is overridden. 5916** ^The pArg argument is passed through to the callback. 5917** ^If the callback on a commit hook function returns non-zero, 5918** then the commit is converted into a rollback. 5919** 5920** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 5921** return the P argument from the previous call of the same function 5922** on the same [database connection] D, or NULL for 5923** the first call for each function on D. 5924** 5925** The commit and rollback hook callbacks are not reentrant. 5926** The callback implementation must not do anything that will modify 5927** the database connection that invoked the callback. Any actions 5928** to modify the database connection must be deferred until after the 5929** completion of the [sqlite3_step()] call that triggered the commit 5930** or rollback hook in the first place. 5931** Note that running any other SQL statements, including SELECT statements, 5932** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 5933** the database connections for the meaning of "modify" in this paragraph. 5934** 5935** ^Registering a NULL function disables the callback. 5936** 5937** ^When the commit hook callback routine returns zero, the [COMMIT] 5938** operation is allowed to continue normally. ^If the commit hook 5939** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 5940** ^The rollback hook is invoked on a rollback that results from a commit 5941** hook returning non-zero, just as it would be with any other rollback. 5942** 5943** ^For the purposes of this API, a transaction is said to have been 5944** rolled back if an explicit "ROLLBACK" statement is executed, or 5945** an error or constraint causes an implicit rollback to occur. 5946** ^The rollback callback is not invoked if a transaction is 5947** automatically rolled back because the database connection is closed. 5948** 5949** See also the [sqlite3_update_hook()] interface. 5950*/ 5951void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 5952void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 5953 5954/* 5955** CAPI3REF: Data Change Notification Callbacks 5956** METHOD: sqlite3 5957** 5958** ^The sqlite3_update_hook() interface registers a callback function 5959** with the [database connection] identified by the first argument 5960** to be invoked whenever a row is updated, inserted or deleted in 5961** a [rowid table]. 5962** ^Any callback set by a previous call to this function 5963** for the same database connection is overridden. 5964** 5965** ^The second argument is a pointer to the function to invoke when a 5966** row is updated, inserted or deleted in a rowid table. 5967** ^The first argument to the callback is a copy of the third argument 5968** to sqlite3_update_hook(). 5969** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 5970** or [SQLITE_UPDATE], depending on the operation that caused the callback 5971** to be invoked. 5972** ^The third and fourth arguments to the callback contain pointers to the 5973** database and table name containing the affected row. 5974** ^The final callback parameter is the [rowid] of the row. 5975** ^In the case of an update, this is the [rowid] after the update takes place. 5976** 5977** ^(The update hook is not invoked when internal system tables are 5978** modified (i.e. sqlite_master and sqlite_sequence).)^ 5979** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified. 5980** 5981** ^In the current implementation, the update hook 5982** is not invoked when conflicting rows are deleted because of an 5983** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 5984** invoked when rows are deleted using the [truncate optimization]. 5985** The exceptions defined in this paragraph might change in a future 5986** release of SQLite. 5987** 5988** The update hook implementation must not do anything that will modify 5989** the database connection that invoked the update hook. Any actions 5990** to modify the database connection must be deferred until after the 5991** completion of the [sqlite3_step()] call that triggered the update hook. 5992** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 5993** database connections for the meaning of "modify" in this paragraph. 5994** 5995** ^The sqlite3_update_hook(D,C,P) function 5996** returns the P argument from the previous call 5997** on the same [database connection] D, or NULL for 5998** the first call on D. 5999** 6000** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()], 6001** and [sqlite3_preupdate_hook()] interfaces. 6002*/ 6003void *sqlite3_update_hook( 6004 sqlite3*, 6005 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 6006 void* 6007); 6008 6009/* 6010** CAPI3REF: Enable Or Disable Shared Pager Cache 6011** 6012** ^(This routine enables or disables the sharing of the database cache 6013** and schema data structures between [database connection | connections] 6014** to the same database. Sharing is enabled if the argument is true 6015** and disabled if the argument is false.)^ 6016** 6017** ^Cache sharing is enabled and disabled for an entire process. 6018** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 6019** In prior versions of SQLite, 6020** sharing was enabled or disabled for each thread separately. 6021** 6022** ^(The cache sharing mode set by this interface effects all subsequent 6023** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 6024** Existing database connections continue use the sharing mode 6025** that was in effect at the time they were opened.)^ 6026** 6027** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 6028** successfully. An [error code] is returned otherwise.)^ 6029** 6030** ^Shared cache is disabled by default. But this might change in 6031** future releases of SQLite. Applications that care about shared 6032** cache setting should set it explicitly. 6033** 6034** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0 6035** and will always return SQLITE_MISUSE. On those systems, 6036** shared cache mode should be enabled per-database connection via 6037** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE]. 6038** 6039** This interface is threadsafe on processors where writing a 6040** 32-bit integer is atomic. 6041** 6042** See Also: [SQLite Shared-Cache Mode] 6043*/ 6044int sqlite3_enable_shared_cache(int); 6045 6046/* 6047** CAPI3REF: Attempt To Free Heap Memory 6048** 6049** ^The sqlite3_release_memory() interface attempts to free N bytes 6050** of heap memory by deallocating non-essential memory allocations 6051** held by the database library. Memory used to cache database 6052** pages to improve performance is an example of non-essential memory. 6053** ^sqlite3_release_memory() returns the number of bytes actually freed, 6054** which might be more or less than the amount requested. 6055** ^The sqlite3_release_memory() routine is a no-op returning zero 6056** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6057** 6058** See also: [sqlite3_db_release_memory()] 6059*/ 6060int sqlite3_release_memory(int); 6061 6062/* 6063** CAPI3REF: Free Memory Used By A Database Connection 6064** METHOD: sqlite3 6065** 6066** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 6067** memory as possible from database connection D. Unlike the 6068** [sqlite3_release_memory()] interface, this interface is in effect even 6069** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 6070** omitted. 6071** 6072** See also: [sqlite3_release_memory()] 6073*/ 6074int sqlite3_db_release_memory(sqlite3*); 6075 6076/* 6077** CAPI3REF: Impose A Limit On Heap Size 6078** 6079** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 6080** soft limit on the amount of heap memory that may be allocated by SQLite. 6081** ^SQLite strives to keep heap memory utilization below the soft heap 6082** limit by reducing the number of pages held in the page cache 6083** as heap memory usages approaches the limit. 6084** ^The soft heap limit is "soft" because even though SQLite strives to stay 6085** below the limit, it will exceed the limit rather than generate 6086** an [SQLITE_NOMEM] error. In other words, the soft heap limit 6087** is advisory only. 6088** 6089** ^The return value from sqlite3_soft_heap_limit64() is the size of 6090** the soft heap limit prior to the call, or negative in the case of an 6091** error. ^If the argument N is negative 6092** then no change is made to the soft heap limit. Hence, the current 6093** size of the soft heap limit can be determined by invoking 6094** sqlite3_soft_heap_limit64() with a negative argument. 6095** 6096** ^If the argument N is zero then the soft heap limit is disabled. 6097** 6098** ^(The soft heap limit is not enforced in the current implementation 6099** if one or more of following conditions are true: 6100** 6101** <ul> 6102** <li> The soft heap limit is set to zero. 6103** <li> Memory accounting is disabled using a combination of the 6104** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 6105** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 6106** <li> An alternative page cache implementation is specified using 6107** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 6108** <li> The page cache allocates from its own memory pool supplied 6109** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 6110** from the heap. 6111** </ul>)^ 6112** 6113** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 6114** the soft heap limit is enforced 6115** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 6116** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 6117** the soft heap limit is enforced on every memory allocation. Without 6118** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 6119** when memory is allocated by the page cache. Testing suggests that because 6120** the page cache is the predominate memory user in SQLite, most 6121** applications will achieve adequate soft heap limit enforcement without 6122** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 6123** 6124** The circumstances under which SQLite will enforce the soft heap limit may 6125** changes in future releases of SQLite. 6126*/ 6127sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 6128 6129/* 6130** CAPI3REF: Deprecated Soft Heap Limit Interface 6131** DEPRECATED 6132** 6133** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 6134** interface. This routine is provided for historical compatibility 6135** only. All new applications should use the 6136** [sqlite3_soft_heap_limit64()] interface rather than this one. 6137*/ 6138SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 6139 6140 6141/* 6142** CAPI3REF: Extract Metadata About A Column Of A Table 6143** METHOD: sqlite3 6144** 6145** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns 6146** information about column C of table T in database D 6147** on [database connection] X.)^ ^The sqlite3_table_column_metadata() 6148** interface returns SQLITE_OK and fills in the non-NULL pointers in 6149** the final five arguments with appropriate values if the specified 6150** column exists. ^The sqlite3_table_column_metadata() interface returns 6151** SQLITE_ERROR and if the specified column does not exist. 6152** ^If the column-name parameter to sqlite3_table_column_metadata() is a 6153** NULL pointer, then this routine simply checks for the existence of the 6154** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it 6155** does not. If the table name parameter T in a call to 6156** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is 6157** undefined behavior. 6158** 6159** ^The column is identified by the second, third and fourth parameters to 6160** this function. ^(The second parameter is either the name of the database 6161** (i.e. "main", "temp", or an attached database) containing the specified 6162** table or NULL.)^ ^If it is NULL, then all attached databases are searched 6163** for the table using the same algorithm used by the database engine to 6164** resolve unqualified table references. 6165** 6166** ^The third and fourth parameters to this function are the table and column 6167** name of the desired column, respectively. 6168** 6169** ^Metadata is returned by writing to the memory locations passed as the 5th 6170** and subsequent parameters to this function. ^Any of these arguments may be 6171** NULL, in which case the corresponding element of metadata is omitted. 6172** 6173** ^(<blockquote> 6174** <table border="1"> 6175** <tr><th> Parameter <th> Output<br>Type <th> Description 6176** 6177** <tr><td> 5th <td> const char* <td> Data type 6178** <tr><td> 6th <td> const char* <td> Name of default collation sequence 6179** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 6180** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 6181** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 6182** </table> 6183** </blockquote>)^ 6184** 6185** ^The memory pointed to by the character pointers returned for the 6186** declaration type and collation sequence is valid until the next 6187** call to any SQLite API function. 6188** 6189** ^If the specified table is actually a view, an [error code] is returned. 6190** 6191** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 6192** is not a [WITHOUT ROWID] table and an 6193** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 6194** parameters are set for the explicitly declared column. ^(If there is no 6195** [INTEGER PRIMARY KEY] column, then the outputs 6196** for the [rowid] are set as follows: 6197** 6198** <pre> 6199** data type: "INTEGER" 6200** collation sequence: "BINARY" 6201** not null: 0 6202** primary key: 1 6203** auto increment: 0 6204** </pre>)^ 6205** 6206** ^This function causes all database schemas to be read from disk and 6207** parsed, if that has not already been done, and returns an error if 6208** any errors are encountered while loading the schema. 6209*/ 6210int sqlite3_table_column_metadata( 6211 sqlite3 *db, /* Connection handle */ 6212 const char *zDbName, /* Database name or NULL */ 6213 const char *zTableName, /* Table name */ 6214 const char *zColumnName, /* Column name */ 6215 char const **pzDataType, /* OUTPUT: Declared data type */ 6216 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 6217 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 6218 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 6219 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 6220); 6221 6222/* 6223** CAPI3REF: Load An Extension 6224** METHOD: sqlite3 6225** 6226** ^This interface loads an SQLite extension library from the named file. 6227** 6228** ^The sqlite3_load_extension() interface attempts to load an 6229** [SQLite extension] library contained in the file zFile. If 6230** the file cannot be loaded directly, attempts are made to load 6231** with various operating-system specific extensions added. 6232** So for example, if "samplelib" cannot be loaded, then names like 6233** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might 6234** be tried also. 6235** 6236** ^The entry point is zProc. 6237** ^(zProc may be 0, in which case SQLite will try to come up with an 6238** entry point name on its own. It first tries "sqlite3_extension_init". 6239** If that does not work, it constructs a name "sqlite3_X_init" where the 6240** X is consists of the lower-case equivalent of all ASCII alphabetic 6241** characters in the filename from the last "/" to the first following 6242** "." and omitting any initial "lib".)^ 6243** ^The sqlite3_load_extension() interface returns 6244** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 6245** ^If an error occurs and pzErrMsg is not 0, then the 6246** [sqlite3_load_extension()] interface shall attempt to 6247** fill *pzErrMsg with error message text stored in memory 6248** obtained from [sqlite3_malloc()]. The calling function 6249** should free this memory by calling [sqlite3_free()]. 6250** 6251** ^Extension loading must be enabled using 6252** [sqlite3_enable_load_extension()] or 6253** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL) 6254** prior to calling this API, 6255** otherwise an error will be returned. 6256** 6257** <b>Security warning:</b> It is recommended that the 6258** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this 6259** interface. The use of the [sqlite3_enable_load_extension()] interface 6260** should be avoided. This will keep the SQL function [load_extension()] 6261** disabled and prevent SQL injections from giving attackers 6262** access to extension loading capabilities. 6263** 6264** See also the [load_extension() SQL function]. 6265*/ 6266int sqlite3_load_extension( 6267 sqlite3 *db, /* Load the extension into this database connection */ 6268 const char *zFile, /* Name of the shared library containing extension */ 6269 const char *zProc, /* Entry point. Derived from zFile if 0 */ 6270 char **pzErrMsg /* Put error message here if not 0 */ 6271); 6272 6273/* 6274** CAPI3REF: Enable Or Disable Extension Loading 6275** METHOD: sqlite3 6276** 6277** ^So as not to open security holes in older applications that are 6278** unprepared to deal with [extension loading], and as a means of disabling 6279** [extension loading] while evaluating user-entered SQL, the following API 6280** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 6281** 6282** ^Extension loading is off by default. 6283** ^Call the sqlite3_enable_load_extension() routine with onoff==1 6284** to turn extension loading on and call it with onoff==0 to turn 6285** it back off again. 6286** 6287** ^This interface enables or disables both the C-API 6288** [sqlite3_load_extension()] and the SQL function [load_extension()]. 6289** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..) 6290** to enable or disable only the C-API.)^ 6291** 6292** <b>Security warning:</b> It is recommended that extension loading 6293** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method 6294** rather than this interface, so the [load_extension()] SQL function 6295** remains disabled. This will prevent SQL injections from giving attackers 6296** access to extension loading capabilities. 6297*/ 6298int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 6299 6300/* 6301** CAPI3REF: Automatically Load Statically Linked Extensions 6302** 6303** ^This interface causes the xEntryPoint() function to be invoked for 6304** each new [database connection] that is created. The idea here is that 6305** xEntryPoint() is the entry point for a statically linked [SQLite extension] 6306** that is to be automatically loaded into all new database connections. 6307** 6308** ^(Even though the function prototype shows that xEntryPoint() takes 6309** no arguments and returns void, SQLite invokes xEntryPoint() with three 6310** arguments and expects an integer result as if the signature of the 6311** entry point where as follows: 6312** 6313** <blockquote><pre> 6314** int xEntryPoint( 6315** sqlite3 *db, 6316** const char **pzErrMsg, 6317** const struct sqlite3_api_routines *pThunk 6318** ); 6319** </pre></blockquote>)^ 6320** 6321** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 6322** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 6323** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 6324** is NULL before calling the xEntryPoint(). ^SQLite will invoke 6325** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 6326** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 6327** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 6328** 6329** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 6330** on the list of automatic extensions is a harmless no-op. ^No entry point 6331** will be called more than once for each database connection that is opened. 6332** 6333** See also: [sqlite3_reset_auto_extension()] 6334** and [sqlite3_cancel_auto_extension()] 6335*/ 6336int sqlite3_auto_extension(void(*xEntryPoint)(void)); 6337 6338/* 6339** CAPI3REF: Cancel Automatic Extension Loading 6340** 6341** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the 6342** initialization routine X that was registered using a prior call to 6343** [sqlite3_auto_extension(X)]. ^The [sqlite3_cancel_auto_extension(X)] 6344** routine returns 1 if initialization routine X was successfully 6345** unregistered and it returns 0 if X was not on the list of initialization 6346** routines. 6347*/ 6348int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void)); 6349 6350/* 6351** CAPI3REF: Reset Automatic Extension Loading 6352** 6353** ^This interface disables all automatic extensions previously 6354** registered using [sqlite3_auto_extension()]. 6355*/ 6356void sqlite3_reset_auto_extension(void); 6357 6358/* 6359** The interface to the virtual-table mechanism is currently considered 6360** to be experimental. The interface might change in incompatible ways. 6361** If this is a problem for you, do not use the interface at this time. 6362** 6363** When the virtual-table mechanism stabilizes, we will declare the 6364** interface fixed, support it indefinitely, and remove this comment. 6365*/ 6366 6367/* 6368** Structures used by the virtual table interface 6369*/ 6370typedef struct sqlite3_vtab sqlite3_vtab; 6371typedef struct sqlite3_index_info sqlite3_index_info; 6372typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 6373typedef struct sqlite3_module sqlite3_module; 6374 6375/* 6376** CAPI3REF: Virtual Table Object 6377** KEYWORDS: sqlite3_module {virtual table module} 6378** 6379** This structure, sometimes called a "virtual table module", 6380** defines the implementation of a [virtual tables]. 6381** This structure consists mostly of methods for the module. 6382** 6383** ^A virtual table module is created by filling in a persistent 6384** instance of this structure and passing a pointer to that instance 6385** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 6386** ^The registration remains valid until it is replaced by a different 6387** module or until the [database connection] closes. The content 6388** of this structure must not change while it is registered with 6389** any database connection. 6390*/ 6391struct sqlite3_module { 6392 int iVersion; 6393 int (*xCreate)(sqlite3*, void *pAux, 6394 int argc, const char *const*argv, 6395 sqlite3_vtab **ppVTab, char**); 6396 int (*xConnect)(sqlite3*, void *pAux, 6397 int argc, const char *const*argv, 6398 sqlite3_vtab **ppVTab, char**); 6399 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 6400 int (*xDisconnect)(sqlite3_vtab *pVTab); 6401 int (*xDestroy)(sqlite3_vtab *pVTab); 6402 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 6403 int (*xClose)(sqlite3_vtab_cursor*); 6404 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 6405 int argc, sqlite3_value **argv); 6406 int (*xNext)(sqlite3_vtab_cursor*); 6407 int (*xEof)(sqlite3_vtab_cursor*); 6408 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 6409 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 6410 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 6411 int (*xBegin)(sqlite3_vtab *pVTab); 6412 int (*xSync)(sqlite3_vtab *pVTab); 6413 int (*xCommit)(sqlite3_vtab *pVTab); 6414 int (*xRollback)(sqlite3_vtab *pVTab); 6415 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 6416 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 6417 void **ppArg); 6418 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 6419 /* The methods above are in version 1 of the sqlite_module object. Those 6420 ** below are for version 2 and greater. */ 6421 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 6422 int (*xRelease)(sqlite3_vtab *pVTab, int); 6423 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 6424 /* The methods above are in versions 1 and 2 of the sqlite_module object. 6425 ** Those below are for version 3 and greater. */ 6426 int (*xShadowName)(const char*); 6427}; 6428 6429/* 6430** CAPI3REF: Virtual Table Indexing Information 6431** KEYWORDS: sqlite3_index_info 6432** 6433** The sqlite3_index_info structure and its substructures is used as part 6434** of the [virtual table] interface to 6435** pass information into and receive the reply from the [xBestIndex] 6436** method of a [virtual table module]. The fields under **Inputs** are the 6437** inputs to xBestIndex and are read-only. xBestIndex inserts its 6438** results into the **Outputs** fields. 6439** 6440** ^(The aConstraint[] array records WHERE clause constraints of the form: 6441** 6442** <blockquote>column OP expr</blockquote> 6443** 6444** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 6445** stored in aConstraint[].op using one of the 6446** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 6447** ^(The index of the column is stored in 6448** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 6449** expr on the right-hand side can be evaluated (and thus the constraint 6450** is usable) and false if it cannot.)^ 6451** 6452** ^The optimizer automatically inverts terms of the form "expr OP column" 6453** and makes other simplifications to the WHERE clause in an attempt to 6454** get as many WHERE clause terms into the form shown above as possible. 6455** ^The aConstraint[] array only reports WHERE clause terms that are 6456** relevant to the particular virtual table being queried. 6457** 6458** ^Information about the ORDER BY clause is stored in aOrderBy[]. 6459** ^Each term of aOrderBy records a column of the ORDER BY clause. 6460** 6461** The colUsed field indicates which columns of the virtual table may be 6462** required by the current scan. Virtual table columns are numbered from 6463** zero in the order in which they appear within the CREATE TABLE statement 6464** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62), 6465** the corresponding bit is set within the colUsed mask if the column may be 6466** required by SQLite. If the table has at least 64 columns and any column 6467** to the right of the first 63 is required, then bit 63 of colUsed is also 6468** set. In other words, column iCol may be required if the expression 6469** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 6470** non-zero. 6471** 6472** The [xBestIndex] method must fill aConstraintUsage[] with information 6473** about what parameters to pass to xFilter. ^If argvIndex>0 then 6474** the right-hand side of the corresponding aConstraint[] is evaluated 6475** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 6476** is true, then the constraint is assumed to be fully handled by the 6477** virtual table and is not checked again by SQLite.)^ 6478** 6479** ^The idxNum and idxPtr values are recorded and passed into the 6480** [xFilter] method. 6481** ^[sqlite3_free()] is used to free idxPtr if and only if 6482** needToFreeIdxPtr is true. 6483** 6484** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 6485** the correct order to satisfy the ORDER BY clause so that no separate 6486** sorting step is required. 6487** 6488** ^The estimatedCost value is an estimate of the cost of a particular 6489** strategy. A cost of N indicates that the cost of the strategy is similar 6490** to a linear scan of an SQLite table with N rows. A cost of log(N) 6491** indicates that the expense of the operation is similar to that of a 6492** binary search on a unique indexed field of an SQLite table with N rows. 6493** 6494** ^The estimatedRows value is an estimate of the number of rows that 6495** will be returned by the strategy. 6496** 6497** The xBestIndex method may optionally populate the idxFlags field with a 6498** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag - 6499** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite 6500** assumes that the strategy may visit at most one row. 6501** 6502** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then 6503** SQLite also assumes that if a call to the xUpdate() method is made as 6504** part of the same statement to delete or update a virtual table row and the 6505** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback 6506** any database changes. In other words, if the xUpdate() returns 6507** SQLITE_CONSTRAINT, the database contents must be exactly as they were 6508** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not 6509** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by 6510** the xUpdate method are automatically rolled back by SQLite. 6511** 6512** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info 6513** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 6514** If a virtual table extension is 6515** used with an SQLite version earlier than 3.8.2, the results of attempting 6516** to read or write the estimatedRows field are undefined (but are likely 6517** to included crashing the application). The estimatedRows field should 6518** therefore only be used if [sqlite3_libversion_number()] returns a 6519** value greater than or equal to 3008002. Similarly, the idxFlags field 6520** was added for [version 3.9.0] ([dateof:3.9.0]). 6521** It may therefore only be used if 6522** sqlite3_libversion_number() returns a value greater than or equal to 6523** 3009000. 6524*/ 6525struct sqlite3_index_info { 6526 /* Inputs */ 6527 int nConstraint; /* Number of entries in aConstraint */ 6528 struct sqlite3_index_constraint { 6529 int iColumn; /* Column constrained. -1 for ROWID */ 6530 unsigned char op; /* Constraint operator */ 6531 unsigned char usable; /* True if this constraint is usable */ 6532 int iTermOffset; /* Used internally - xBestIndex should ignore */ 6533 } *aConstraint; /* Table of WHERE clause constraints */ 6534 int nOrderBy; /* Number of terms in the ORDER BY clause */ 6535 struct sqlite3_index_orderby { 6536 int iColumn; /* Column number */ 6537 unsigned char desc; /* True for DESC. False for ASC. */ 6538 } *aOrderBy; /* The ORDER BY clause */ 6539 /* Outputs */ 6540 struct sqlite3_index_constraint_usage { 6541 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 6542 unsigned char omit; /* Do not code a test for this constraint */ 6543 } *aConstraintUsage; 6544 int idxNum; /* Number used to identify the index */ 6545 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 6546 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 6547 int orderByConsumed; /* True if output is already ordered */ 6548 double estimatedCost; /* Estimated cost of using this index */ 6549 /* Fields below are only available in SQLite 3.8.2 and later */ 6550 sqlite3_int64 estimatedRows; /* Estimated number of rows returned */ 6551 /* Fields below are only available in SQLite 3.9.0 and later */ 6552 int idxFlags; /* Mask of SQLITE_INDEX_SCAN_* flags */ 6553 /* Fields below are only available in SQLite 3.10.0 and later */ 6554 sqlite3_uint64 colUsed; /* Input: Mask of columns used by statement */ 6555}; 6556 6557/* 6558** CAPI3REF: Virtual Table Scan Flags 6559** 6560** Virtual table implementations are allowed to set the 6561** [sqlite3_index_info].idxFlags field to some combination of 6562** these bits. 6563*/ 6564#define SQLITE_INDEX_SCAN_UNIQUE 1 /* Scan visits at most 1 row */ 6565 6566/* 6567** CAPI3REF: Virtual Table Constraint Operator Codes 6568** 6569** These macros defined the allowed values for the 6570** [sqlite3_index_info].aConstraint[].op field. Each value represents 6571** an operator that is part of a constraint term in the wHERE clause of 6572** a query that uses a [virtual table]. 6573*/ 6574#define SQLITE_INDEX_CONSTRAINT_EQ 2 6575#define SQLITE_INDEX_CONSTRAINT_GT 4 6576#define SQLITE_INDEX_CONSTRAINT_LE 8 6577#define SQLITE_INDEX_CONSTRAINT_LT 16 6578#define SQLITE_INDEX_CONSTRAINT_GE 32 6579#define SQLITE_INDEX_CONSTRAINT_MATCH 64 6580#define SQLITE_INDEX_CONSTRAINT_LIKE 65 6581#define SQLITE_INDEX_CONSTRAINT_GLOB 66 6582#define SQLITE_INDEX_CONSTRAINT_REGEXP 67 6583#define SQLITE_INDEX_CONSTRAINT_NE 68 6584#define SQLITE_INDEX_CONSTRAINT_ISNOT 69 6585#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70 6586#define SQLITE_INDEX_CONSTRAINT_ISNULL 71 6587#define SQLITE_INDEX_CONSTRAINT_IS 72 6588#define SQLITE_INDEX_CONSTRAINT_FUNCTION 150 6589 6590/* 6591** CAPI3REF: Register A Virtual Table Implementation 6592** METHOD: sqlite3 6593** 6594** ^These routines are used to register a new [virtual table module] name. 6595** ^Module names must be registered before 6596** creating a new [virtual table] using the module and before using a 6597** preexisting [virtual table] for the module. 6598** 6599** ^The module name is registered on the [database connection] specified 6600** by the first parameter. ^The name of the module is given by the 6601** second parameter. ^The third parameter is a pointer to 6602** the implementation of the [virtual table module]. ^The fourth 6603** parameter is an arbitrary client data pointer that is passed through 6604** into the [xCreate] and [xConnect] methods of the virtual table module 6605** when a new virtual table is be being created or reinitialized. 6606** 6607** ^The sqlite3_create_module_v2() interface has a fifth parameter which 6608** is a pointer to a destructor for the pClientData. ^SQLite will 6609** invoke the destructor function (if it is not NULL) when SQLite 6610** no longer needs the pClientData pointer. ^The destructor will also 6611** be invoked if the call to sqlite3_create_module_v2() fails. 6612** ^The sqlite3_create_module() 6613** interface is equivalent to sqlite3_create_module_v2() with a NULL 6614** destructor. 6615*/ 6616int sqlite3_create_module( 6617 sqlite3 *db, /* SQLite connection to register module with */ 6618 const char *zName, /* Name of the module */ 6619 const sqlite3_module *p, /* Methods for the module */ 6620 void *pClientData /* Client data for xCreate/xConnect */ 6621); 6622int sqlite3_create_module_v2( 6623 sqlite3 *db, /* SQLite connection to register module with */ 6624 const char *zName, /* Name of the module */ 6625 const sqlite3_module *p, /* Methods for the module */ 6626 void *pClientData, /* Client data for xCreate/xConnect */ 6627 void(*xDestroy)(void*) /* Module destructor function */ 6628); 6629 6630/* 6631** CAPI3REF: Virtual Table Instance Object 6632** KEYWORDS: sqlite3_vtab 6633** 6634** Every [virtual table module] implementation uses a subclass 6635** of this object to describe a particular instance 6636** of the [virtual table]. Each subclass will 6637** be tailored to the specific needs of the module implementation. 6638** The purpose of this superclass is to define certain fields that are 6639** common to all module implementations. 6640** 6641** ^Virtual tables methods can set an error message by assigning a 6642** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 6643** take care that any prior string is freed by a call to [sqlite3_free()] 6644** prior to assigning a new string to zErrMsg. ^After the error message 6645** is delivered up to the client application, the string will be automatically 6646** freed by sqlite3_free() and the zErrMsg field will be zeroed. 6647*/ 6648struct sqlite3_vtab { 6649 const sqlite3_module *pModule; /* The module for this virtual table */ 6650 int nRef; /* Number of open cursors */ 6651 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 6652 /* Virtual table implementations will typically add additional fields */ 6653}; 6654 6655/* 6656** CAPI3REF: Virtual Table Cursor Object 6657** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 6658** 6659** Every [virtual table module] implementation uses a subclass of the 6660** following structure to describe cursors that point into the 6661** [virtual table] and are used 6662** to loop through the virtual table. Cursors are created using the 6663** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 6664** by the [sqlite3_module.xClose | xClose] method. Cursors are used 6665** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 6666** of the module. Each module implementation will define 6667** the content of a cursor structure to suit its own needs. 6668** 6669** This superclass exists in order to define fields of the cursor that 6670** are common to all implementations. 6671*/ 6672struct sqlite3_vtab_cursor { 6673 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 6674 /* Virtual table implementations will typically add additional fields */ 6675}; 6676 6677/* 6678** CAPI3REF: Declare The Schema Of A Virtual Table 6679** 6680** ^The [xCreate] and [xConnect] methods of a 6681** [virtual table module] call this interface 6682** to declare the format (the names and datatypes of the columns) of 6683** the virtual tables they implement. 6684*/ 6685int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 6686 6687/* 6688** CAPI3REF: Overload A Function For A Virtual Table 6689** METHOD: sqlite3 6690** 6691** ^(Virtual tables can provide alternative implementations of functions 6692** using the [xFindFunction] method of the [virtual table module]. 6693** But global versions of those functions 6694** must exist in order to be overloaded.)^ 6695** 6696** ^(This API makes sure a global version of a function with a particular 6697** name and number of parameters exists. If no such function exists 6698** before this API is called, a new function is created.)^ ^The implementation 6699** of the new function always causes an exception to be thrown. So 6700** the new function is not good for anything by itself. Its only 6701** purpose is to be a placeholder function that can be overloaded 6702** by a [virtual table]. 6703*/ 6704int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 6705 6706/* 6707** The interface to the virtual-table mechanism defined above (back up 6708** to a comment remarkably similar to this one) is currently considered 6709** to be experimental. The interface might change in incompatible ways. 6710** If this is a problem for you, do not use the interface at this time. 6711** 6712** When the virtual-table mechanism stabilizes, we will declare the 6713** interface fixed, support it indefinitely, and remove this comment. 6714*/ 6715 6716/* 6717** CAPI3REF: A Handle To An Open BLOB 6718** KEYWORDS: {BLOB handle} {BLOB handles} 6719** 6720** An instance of this object represents an open BLOB on which 6721** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 6722** ^Objects of this type are created by [sqlite3_blob_open()] 6723** and destroyed by [sqlite3_blob_close()]. 6724** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 6725** can be used to read or write small subsections of the BLOB. 6726** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 6727*/ 6728typedef struct sqlite3_blob sqlite3_blob; 6729 6730/* 6731** CAPI3REF: Open A BLOB For Incremental I/O 6732** METHOD: sqlite3 6733** CONSTRUCTOR: sqlite3_blob 6734** 6735** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 6736** in row iRow, column zColumn, table zTable in database zDb; 6737** in other words, the same BLOB that would be selected by: 6738** 6739** <pre> 6740** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 6741** </pre>)^ 6742** 6743** ^(Parameter zDb is not the filename that contains the database, but 6744** rather the symbolic name of the database. For attached databases, this is 6745** the name that appears after the AS keyword in the [ATTACH] statement. 6746** For the main database file, the database name is "main". For TEMP 6747** tables, the database name is "temp".)^ 6748** 6749** ^If the flags parameter is non-zero, then the BLOB is opened for read 6750** and write access. ^If the flags parameter is zero, the BLOB is opened for 6751** read-only access. 6752** 6753** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored 6754** in *ppBlob. Otherwise an [error code] is returned and, unless the error 6755** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided 6756** the API is not misused, it is always safe to call [sqlite3_blob_close()] 6757** on *ppBlob after this function it returns. 6758** 6759** This function fails with SQLITE_ERROR if any of the following are true: 6760** <ul> 6761** <li> ^(Database zDb does not exist)^, 6762** <li> ^(Table zTable does not exist within database zDb)^, 6763** <li> ^(Table zTable is a WITHOUT ROWID table)^, 6764** <li> ^(Column zColumn does not exist)^, 6765** <li> ^(Row iRow is not present in the table)^, 6766** <li> ^(The specified column of row iRow contains a value that is not 6767** a TEXT or BLOB value)^, 6768** <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 6769** constraint and the blob is being opened for read/write access)^, 6770** <li> ^([foreign key constraints | Foreign key constraints] are enabled, 6771** column zColumn is part of a [child key] definition and the blob is 6772** being opened for read/write access)^. 6773** </ul> 6774** 6775** ^Unless it returns SQLITE_MISUSE, this function sets the 6776** [database connection] error code and message accessible via 6777** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6778** 6779** A BLOB referenced by sqlite3_blob_open() may be read using the 6780** [sqlite3_blob_read()] interface and modified by using 6781** [sqlite3_blob_write()]. The [BLOB handle] can be moved to a 6782** different row of the same table using the [sqlite3_blob_reopen()] 6783** interface. However, the column, table, or database of a [BLOB handle] 6784** cannot be changed after the [BLOB handle] is opened. 6785** 6786** ^(If the row that a BLOB handle points to is modified by an 6787** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 6788** then the BLOB handle is marked as "expired". 6789** This is true if any column of the row is changed, even a column 6790** other than the one the BLOB handle is open on.)^ 6791** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 6792** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 6793** ^(Changes written into a BLOB prior to the BLOB expiring are not 6794** rolled back by the expiration of the BLOB. Such changes will eventually 6795** commit if the transaction continues to completion.)^ 6796** 6797** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 6798** the opened blob. ^The size of a blob may not be changed by this 6799** interface. Use the [UPDATE] SQL command to change the size of a 6800** blob. 6801** 6802** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 6803** and the built-in [zeroblob] SQL function may be used to create a 6804** zero-filled blob to read or write using the incremental-blob interface. 6805** 6806** To avoid a resource leak, every open [BLOB handle] should eventually 6807** be released by a call to [sqlite3_blob_close()]. 6808** 6809** See also: [sqlite3_blob_close()], 6810** [sqlite3_blob_reopen()], [sqlite3_blob_read()], 6811** [sqlite3_blob_bytes()], [sqlite3_blob_write()]. 6812*/ 6813int sqlite3_blob_open( 6814 sqlite3*, 6815 const char *zDb, 6816 const char *zTable, 6817 const char *zColumn, 6818 sqlite3_int64 iRow, 6819 int flags, 6820 sqlite3_blob **ppBlob 6821); 6822 6823/* 6824** CAPI3REF: Move a BLOB Handle to a New Row 6825** METHOD: sqlite3_blob 6826** 6827** ^This function is used to move an existing [BLOB handle] so that it points 6828** to a different row of the same database table. ^The new row is identified 6829** by the rowid value passed as the second argument. Only the row can be 6830** changed. ^The database, table and column on which the blob handle is open 6831** remain the same. Moving an existing [BLOB handle] to a new row is 6832** faster than closing the existing handle and opening a new one. 6833** 6834** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 6835** it must exist and there must be either a blob or text value stored in 6836** the nominated column.)^ ^If the new row is not present in the table, or if 6837** it does not contain a blob or text value, or if another error occurs, an 6838** SQLite error code is returned and the blob handle is considered aborted. 6839** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 6840** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 6841** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 6842** always returns zero. 6843** 6844** ^This function sets the database handle error code and message. 6845*/ 6846int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 6847 6848/* 6849** CAPI3REF: Close A BLOB Handle 6850** DESTRUCTOR: sqlite3_blob 6851** 6852** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed 6853** unconditionally. Even if this routine returns an error code, the 6854** handle is still closed.)^ 6855** 6856** ^If the blob handle being closed was opened for read-write access, and if 6857** the database is in auto-commit mode and there are no other open read-write 6858** blob handles or active write statements, the current transaction is 6859** committed. ^If an error occurs while committing the transaction, an error 6860** code is returned and the transaction rolled back. 6861** 6862** Calling this function with an argument that is not a NULL pointer or an 6863** open blob handle results in undefined behaviour. ^Calling this routine 6864** with a null pointer (such as would be returned by a failed call to 6865** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function 6866** is passed a valid open blob handle, the values returned by the 6867** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning. 6868*/ 6869int sqlite3_blob_close(sqlite3_blob *); 6870 6871/* 6872** CAPI3REF: Return The Size Of An Open BLOB 6873** METHOD: sqlite3_blob 6874** 6875** ^Returns the size in bytes of the BLOB accessible via the 6876** successfully opened [BLOB handle] in its only argument. ^The 6877** incremental blob I/O routines can only read or overwriting existing 6878** blob content; they cannot change the size of a blob. 6879** 6880** This routine only works on a [BLOB handle] which has been created 6881** by a prior successful call to [sqlite3_blob_open()] and which has not 6882** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6883** to this routine results in undefined and probably undesirable behavior. 6884*/ 6885int sqlite3_blob_bytes(sqlite3_blob *); 6886 6887/* 6888** CAPI3REF: Read Data From A BLOB Incrementally 6889** METHOD: sqlite3_blob 6890** 6891** ^(This function is used to read data from an open [BLOB handle] into a 6892** caller-supplied buffer. N bytes of data are copied into buffer Z 6893** from the open BLOB, starting at offset iOffset.)^ 6894** 6895** ^If offset iOffset is less than N bytes from the end of the BLOB, 6896** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 6897** less than zero, [SQLITE_ERROR] is returned and no data is read. 6898** ^The size of the blob (and hence the maximum value of N+iOffset) 6899** can be determined using the [sqlite3_blob_bytes()] interface. 6900** 6901** ^An attempt to read from an expired [BLOB handle] fails with an 6902** error code of [SQLITE_ABORT]. 6903** 6904** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 6905** Otherwise, an [error code] or an [extended error code] is returned.)^ 6906** 6907** This routine only works on a [BLOB handle] which has been created 6908** by a prior successful call to [sqlite3_blob_open()] and which has not 6909** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6910** to this routine results in undefined and probably undesirable behavior. 6911** 6912** See also: [sqlite3_blob_write()]. 6913*/ 6914int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 6915 6916/* 6917** CAPI3REF: Write Data Into A BLOB Incrementally 6918** METHOD: sqlite3_blob 6919** 6920** ^(This function is used to write data into an open [BLOB handle] from a 6921** caller-supplied buffer. N bytes of data are copied from the buffer Z 6922** into the open BLOB, starting at offset iOffset.)^ 6923** 6924** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 6925** Otherwise, an [error code] or an [extended error code] is returned.)^ 6926** ^Unless SQLITE_MISUSE is returned, this function sets the 6927** [database connection] error code and message accessible via 6928** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 6929** 6930** ^If the [BLOB handle] passed as the first argument was not opened for 6931** writing (the flags parameter to [sqlite3_blob_open()] was zero), 6932** this function returns [SQLITE_READONLY]. 6933** 6934** This function may only modify the contents of the BLOB; it is 6935** not possible to increase the size of a BLOB using this API. 6936** ^If offset iOffset is less than N bytes from the end of the BLOB, 6937** [SQLITE_ERROR] is returned and no data is written. The size of the 6938** BLOB (and hence the maximum value of N+iOffset) can be determined 6939** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 6940** than zero [SQLITE_ERROR] is returned and no data is written. 6941** 6942** ^An attempt to write to an expired [BLOB handle] fails with an 6943** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 6944** before the [BLOB handle] expired are not rolled back by the 6945** expiration of the handle, though of course those changes might 6946** have been overwritten by the statement that expired the BLOB handle 6947** or by other independent statements. 6948** 6949** This routine only works on a [BLOB handle] which has been created 6950** by a prior successful call to [sqlite3_blob_open()] and which has not 6951** been closed by [sqlite3_blob_close()]. Passing any other pointer in 6952** to this routine results in undefined and probably undesirable behavior. 6953** 6954** See also: [sqlite3_blob_read()]. 6955*/ 6956int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 6957 6958/* 6959** CAPI3REF: Virtual File System Objects 6960** 6961** A virtual filesystem (VFS) is an [sqlite3_vfs] object 6962** that SQLite uses to interact 6963** with the underlying operating system. Most SQLite builds come with a 6964** single default VFS that is appropriate for the host computer. 6965** New VFSes can be registered and existing VFSes can be unregistered. 6966** The following interfaces are provided. 6967** 6968** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 6969** ^Names are case sensitive. 6970** ^Names are zero-terminated UTF-8 strings. 6971** ^If there is no match, a NULL pointer is returned. 6972** ^If zVfsName is NULL then the default VFS is returned. 6973** 6974** ^New VFSes are registered with sqlite3_vfs_register(). 6975** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 6976** ^The same VFS can be registered multiple times without injury. 6977** ^To make an existing VFS into the default VFS, register it again 6978** with the makeDflt flag set. If two different VFSes with the 6979** same name are registered, the behavior is undefined. If a 6980** VFS is registered with a name that is NULL or an empty string, 6981** then the behavior is undefined. 6982** 6983** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 6984** ^(If the default VFS is unregistered, another VFS is chosen as 6985** the default. The choice for the new VFS is arbitrary.)^ 6986*/ 6987sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 6988int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 6989int sqlite3_vfs_unregister(sqlite3_vfs*); 6990 6991/* 6992** CAPI3REF: Mutexes 6993** 6994** The SQLite core uses these routines for thread 6995** synchronization. Though they are intended for internal 6996** use by SQLite, code that links against SQLite is 6997** permitted to use any of these routines. 6998** 6999** The SQLite source code contains multiple implementations 7000** of these mutex routines. An appropriate implementation 7001** is selected automatically at compile-time. The following 7002** implementations are available in the SQLite core: 7003** 7004** <ul> 7005** <li> SQLITE_MUTEX_PTHREADS 7006** <li> SQLITE_MUTEX_W32 7007** <li> SQLITE_MUTEX_NOOP 7008** </ul> 7009** 7010** The SQLITE_MUTEX_NOOP implementation is a set of routines 7011** that does no real locking and is appropriate for use in 7012** a single-threaded application. The SQLITE_MUTEX_PTHREADS and 7013** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix 7014** and Windows. 7015** 7016** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 7017** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 7018** implementation is included with the library. In this case the 7019** application must supply a custom mutex implementation using the 7020** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 7021** before calling sqlite3_initialize() or any other public sqlite3_ 7022** function that calls sqlite3_initialize(). 7023** 7024** ^The sqlite3_mutex_alloc() routine allocates a new 7025** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc() 7026** routine returns NULL if it is unable to allocate the requested 7027** mutex. The argument to sqlite3_mutex_alloc() must one of these 7028** integer constants: 7029** 7030** <ul> 7031** <li> SQLITE_MUTEX_FAST 7032** <li> SQLITE_MUTEX_RECURSIVE 7033** <li> SQLITE_MUTEX_STATIC_MASTER 7034** <li> SQLITE_MUTEX_STATIC_MEM 7035** <li> SQLITE_MUTEX_STATIC_OPEN 7036** <li> SQLITE_MUTEX_STATIC_PRNG 7037** <li> SQLITE_MUTEX_STATIC_LRU 7038** <li> SQLITE_MUTEX_STATIC_PMEM 7039** <li> SQLITE_MUTEX_STATIC_APP1 7040** <li> SQLITE_MUTEX_STATIC_APP2 7041** <li> SQLITE_MUTEX_STATIC_APP3 7042** <li> SQLITE_MUTEX_STATIC_VFS1 7043** <li> SQLITE_MUTEX_STATIC_VFS2 7044** <li> SQLITE_MUTEX_STATIC_VFS3 7045** </ul> 7046** 7047** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 7048** cause sqlite3_mutex_alloc() to create 7049** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 7050** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 7051** The mutex implementation does not need to make a distinction 7052** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 7053** not want to. SQLite will only request a recursive mutex in 7054** cases where it really needs one. If a faster non-recursive mutex 7055** implementation is available on the host platform, the mutex subsystem 7056** might return such a mutex in response to SQLITE_MUTEX_FAST. 7057** 7058** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 7059** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 7060** a pointer to a static preexisting mutex. ^Nine static mutexes are 7061** used by the current version of SQLite. Future versions of SQLite 7062** may add additional static mutexes. Static mutexes are for internal 7063** use by SQLite only. Applications that use SQLite mutexes should 7064** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 7065** SQLITE_MUTEX_RECURSIVE. 7066** 7067** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 7068** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 7069** returns a different mutex on every call. ^For the static 7070** mutex types, the same mutex is returned on every call that has 7071** the same type number. 7072** 7073** ^The sqlite3_mutex_free() routine deallocates a previously 7074** allocated dynamic mutex. Attempting to deallocate a static 7075** mutex results in undefined behavior. 7076** 7077** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 7078** to enter a mutex. ^If another thread is already within the mutex, 7079** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 7080** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 7081** upon successful entry. ^(Mutexes created using 7082** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 7083** In such cases, the 7084** mutex must be exited an equal number of times before another thread 7085** can enter.)^ If the same thread tries to enter any mutex other 7086** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined. 7087** 7088** ^(Some systems (for example, Windows 95) do not support the operation 7089** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 7090** will always return SQLITE_BUSY. The SQLite core only ever uses 7091** sqlite3_mutex_try() as an optimization so this is acceptable 7092** behavior.)^ 7093** 7094** ^The sqlite3_mutex_leave() routine exits a mutex that was 7095** previously entered by the same thread. The behavior 7096** is undefined if the mutex is not currently entered by the 7097** calling thread or is not currently allocated. 7098** 7099** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 7100** sqlite3_mutex_leave() is a NULL pointer, then all three routines 7101** behave as no-ops. 7102** 7103** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 7104*/ 7105sqlite3_mutex *sqlite3_mutex_alloc(int); 7106void sqlite3_mutex_free(sqlite3_mutex*); 7107void sqlite3_mutex_enter(sqlite3_mutex*); 7108int sqlite3_mutex_try(sqlite3_mutex*); 7109void sqlite3_mutex_leave(sqlite3_mutex*); 7110 7111/* 7112** CAPI3REF: Mutex Methods Object 7113** 7114** An instance of this structure defines the low-level routines 7115** used to allocate and use mutexes. 7116** 7117** Usually, the default mutex implementations provided by SQLite are 7118** sufficient, however the application has the option of substituting a custom 7119** implementation for specialized deployments or systems for which SQLite 7120** does not provide a suitable implementation. In this case, the application 7121** creates and populates an instance of this structure to pass 7122** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 7123** Additionally, an instance of this structure can be used as an 7124** output variable when querying the system for the current mutex 7125** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 7126** 7127** ^The xMutexInit method defined by this structure is invoked as 7128** part of system initialization by the sqlite3_initialize() function. 7129** ^The xMutexInit routine is called by SQLite exactly once for each 7130** effective call to [sqlite3_initialize()]. 7131** 7132** ^The xMutexEnd method defined by this structure is invoked as 7133** part of system shutdown by the sqlite3_shutdown() function. The 7134** implementation of this method is expected to release all outstanding 7135** resources obtained by the mutex methods implementation, especially 7136** those obtained by the xMutexInit method. ^The xMutexEnd() 7137** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 7138** 7139** ^(The remaining seven methods defined by this structure (xMutexAlloc, 7140** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 7141** xMutexNotheld) implement the following interfaces (respectively): 7142** 7143** <ul> 7144** <li> [sqlite3_mutex_alloc()] </li> 7145** <li> [sqlite3_mutex_free()] </li> 7146** <li> [sqlite3_mutex_enter()] </li> 7147** <li> [sqlite3_mutex_try()] </li> 7148** <li> [sqlite3_mutex_leave()] </li> 7149** <li> [sqlite3_mutex_held()] </li> 7150** <li> [sqlite3_mutex_notheld()] </li> 7151** </ul>)^ 7152** 7153** The only difference is that the public sqlite3_XXX functions enumerated 7154** above silently ignore any invocations that pass a NULL pointer instead 7155** of a valid mutex handle. The implementations of the methods defined 7156** by this structure are not required to handle this case, the results 7157** of passing a NULL pointer instead of a valid mutex handle are undefined 7158** (i.e. it is acceptable to provide an implementation that segfaults if 7159** it is passed a NULL pointer). 7160** 7161** The xMutexInit() method must be threadsafe. It must be harmless to 7162** invoke xMutexInit() multiple times within the same process and without 7163** intervening calls to xMutexEnd(). Second and subsequent calls to 7164** xMutexInit() must be no-ops. 7165** 7166** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 7167** and its associates). Similarly, xMutexAlloc() must not use SQLite memory 7168** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 7169** memory allocation for a fast or recursive mutex. 7170** 7171** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 7172** called, but only if the prior call to xMutexInit returned SQLITE_OK. 7173** If xMutexInit fails in any way, it is expected to clean up after itself 7174** prior to returning. 7175*/ 7176typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 7177struct sqlite3_mutex_methods { 7178 int (*xMutexInit)(void); 7179 int (*xMutexEnd)(void); 7180 sqlite3_mutex *(*xMutexAlloc)(int); 7181 void (*xMutexFree)(sqlite3_mutex *); 7182 void (*xMutexEnter)(sqlite3_mutex *); 7183 int (*xMutexTry)(sqlite3_mutex *); 7184 void (*xMutexLeave)(sqlite3_mutex *); 7185 int (*xMutexHeld)(sqlite3_mutex *); 7186 int (*xMutexNotheld)(sqlite3_mutex *); 7187}; 7188 7189/* 7190** CAPI3REF: Mutex Verification Routines 7191** 7192** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 7193** are intended for use inside assert() statements. The SQLite core 7194** never uses these routines except inside an assert() and applications 7195** are advised to follow the lead of the core. The SQLite core only 7196** provides implementations for these routines when it is compiled 7197** with the SQLITE_DEBUG flag. External mutex implementations 7198** are only required to provide these routines if SQLITE_DEBUG is 7199** defined and if NDEBUG is not defined. 7200** 7201** These routines should return true if the mutex in their argument 7202** is held or not held, respectively, by the calling thread. 7203** 7204** The implementation is not required to provide versions of these 7205** routines that actually work. If the implementation does not provide working 7206** versions of these routines, it should at least provide stubs that always 7207** return true so that one does not get spurious assertion failures. 7208** 7209** If the argument to sqlite3_mutex_held() is a NULL pointer then 7210** the routine should return 1. This seems counter-intuitive since 7211** clearly the mutex cannot be held if it does not exist. But 7212** the reason the mutex does not exist is because the build is not 7213** using mutexes. And we do not want the assert() containing the 7214** call to sqlite3_mutex_held() to fail, so a non-zero return is 7215** the appropriate thing to do. The sqlite3_mutex_notheld() 7216** interface should also return 1 when given a NULL pointer. 7217*/ 7218#ifndef NDEBUG 7219int sqlite3_mutex_held(sqlite3_mutex*); 7220int sqlite3_mutex_notheld(sqlite3_mutex*); 7221#endif 7222 7223/* 7224** CAPI3REF: Mutex Types 7225** 7226** The [sqlite3_mutex_alloc()] interface takes a single argument 7227** which is one of these integer constants. 7228** 7229** The set of static mutexes may change from one SQLite release to the 7230** next. Applications that override the built-in mutex logic must be 7231** prepared to accommodate additional static mutexes. 7232*/ 7233#define SQLITE_MUTEX_FAST 0 7234#define SQLITE_MUTEX_RECURSIVE 1 7235#define SQLITE_MUTEX_STATIC_MASTER 2 7236#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 7237#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 7238#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 7239#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_randomness() */ 7240#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 7241#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 7242#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 7243#define SQLITE_MUTEX_STATIC_APP1 8 /* For use by application */ 7244#define SQLITE_MUTEX_STATIC_APP2 9 /* For use by application */ 7245#define SQLITE_MUTEX_STATIC_APP3 10 /* For use by application */ 7246#define SQLITE_MUTEX_STATIC_VFS1 11 /* For use by built-in VFS */ 7247#define SQLITE_MUTEX_STATIC_VFS2 12 /* For use by extension VFS */ 7248#define SQLITE_MUTEX_STATIC_VFS3 13 /* For use by application VFS */ 7249 7250/* 7251** CAPI3REF: Retrieve the mutex for a database connection 7252** METHOD: sqlite3 7253** 7254** ^This interface returns a pointer the [sqlite3_mutex] object that 7255** serializes access to the [database connection] given in the argument 7256** when the [threading mode] is Serialized. 7257** ^If the [threading mode] is Single-thread or Multi-thread then this 7258** routine returns a NULL pointer. 7259*/ 7260sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 7261 7262/* 7263** CAPI3REF: Low-Level Control Of Database Files 7264** METHOD: sqlite3 7265** KEYWORDS: {file control} 7266** 7267** ^The [sqlite3_file_control()] interface makes a direct call to the 7268** xFileControl method for the [sqlite3_io_methods] object associated 7269** with a particular database identified by the second argument. ^The 7270** name of the database is "main" for the main database or "temp" for the 7271** TEMP database, or the name that appears after the AS keyword for 7272** databases that are added using the [ATTACH] SQL command. 7273** ^A NULL pointer can be used in place of "main" to refer to the 7274** main database file. 7275** ^The third and fourth parameters to this routine 7276** are passed directly through to the second and third parameters of 7277** the xFileControl method. ^The return value of the xFileControl 7278** method becomes the return value of this routine. 7279** 7280** A few opcodes for [sqlite3_file_control()] are handled directly 7281** by the SQLite core and never invoke the 7282** sqlite3_io_methods.xFileControl method. 7283** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes 7284** a pointer to the underlying [sqlite3_file] object to be written into 7285** the space pointed to by the 4th parameter. The 7286** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns 7287** the [sqlite3_file] object associated with the journal file instead of 7288** the main database. The [SQLITE_FCNTL_VFS_POINTER] opcode returns 7289** a pointer to the underlying [sqlite3_vfs] object for the file. 7290** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter 7291** from the pager. 7292** 7293** ^If the second parameter (zDbName) does not match the name of any 7294** open database file, then SQLITE_ERROR is returned. ^This error 7295** code is not remembered and will not be recalled by [sqlite3_errcode()] 7296** or [sqlite3_errmsg()]. The underlying xFileControl method might 7297** also return SQLITE_ERROR. There is no way to distinguish between 7298** an incorrect zDbName and an SQLITE_ERROR return from the underlying 7299** xFileControl method. 7300** 7301** See also: [file control opcodes] 7302*/ 7303int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 7304 7305/* 7306** CAPI3REF: Testing Interface 7307** 7308** ^The sqlite3_test_control() interface is used to read out internal 7309** state of SQLite and to inject faults into SQLite for testing 7310** purposes. ^The first parameter is an operation code that determines 7311** the number, meaning, and operation of all subsequent parameters. 7312** 7313** This interface is not for use by applications. It exists solely 7314** for verifying the correct operation of the SQLite library. Depending 7315** on how the SQLite library is compiled, this interface might not exist. 7316** 7317** The details of the operation codes, their meanings, the parameters 7318** they take, and what they do are all subject to change without notice. 7319** Unlike most of the SQLite API, this function is not guaranteed to 7320** operate consistently from one release to the next. 7321*/ 7322int sqlite3_test_control(int op, ...); 7323 7324/* 7325** CAPI3REF: Testing Interface Operation Codes 7326** 7327** These constants are the valid operation code parameters used 7328** as the first argument to [sqlite3_test_control()]. 7329** 7330** These parameters and their meanings are subject to change 7331** without notice. These values are for testing purposes only. 7332** Applications should not use any of these parameters or the 7333** [sqlite3_test_control()] interface. 7334*/ 7335#define SQLITE_TESTCTRL_FIRST 5 7336#define SQLITE_TESTCTRL_PRNG_SAVE 5 7337#define SQLITE_TESTCTRL_PRNG_RESTORE 6 7338#define SQLITE_TESTCTRL_PRNG_RESET 7 /* NOT USED */ 7339#define SQLITE_TESTCTRL_BITVEC_TEST 8 7340#define SQLITE_TESTCTRL_FAULT_INSTALL 9 7341#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 7342#define SQLITE_TESTCTRL_PENDING_BYTE 11 7343#define SQLITE_TESTCTRL_ASSERT 12 7344#define SQLITE_TESTCTRL_ALWAYS 13 7345#define SQLITE_TESTCTRL_RESERVE 14 7346#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 7347#define SQLITE_TESTCTRL_ISKEYWORD 16 /* NOT USED */ 7348#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 /* NOT USED */ 7349#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS 17 7350#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 7351#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 /* NOT USED */ 7352#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD 19 7353#define SQLITE_TESTCTRL_NEVER_CORRUPT 20 7354#define SQLITE_TESTCTRL_VDBE_COVERAGE 21 7355#define SQLITE_TESTCTRL_BYTEORDER 22 7356#define SQLITE_TESTCTRL_ISINIT 23 7357#define SQLITE_TESTCTRL_SORTER_MMAP 24 7358#define SQLITE_TESTCTRL_IMPOSTER 25 7359#define SQLITE_TESTCTRL_PARSER_COVERAGE 26 7360#define SQLITE_TESTCTRL_RESULT_INTREAL 27 7361#define SQLITE_TESTCTRL_PRNG_SEED 28 7362#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS 29 7363#define SQLITE_TESTCTRL_LAST 29 /* Largest TESTCTRL */ 7364 7365/* 7366** CAPI3REF: SQL Keyword Checking 7367** 7368** These routines provide access to the set of SQL language keywords 7369** recognized by SQLite. Applications can uses these routines to determine 7370** whether or not a specific identifier needs to be escaped (for example, 7371** by enclosing in double-quotes) so as not to confuse the parser. 7372** 7373** The sqlite3_keyword_count() interface returns the number of distinct 7374** keywords understood by SQLite. 7375** 7376** The sqlite3_keyword_name(N,Z,L) interface finds the N-th keyword and 7377** makes *Z point to that keyword expressed as UTF8 and writes the number 7378** of bytes in the keyword into *L. The string that *Z points to is not 7379** zero-terminated. The sqlite3_keyword_name(N,Z,L) routine returns 7380** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z 7381** or L are NULL or invalid pointers then calls to 7382** sqlite3_keyword_name(N,Z,L) result in undefined behavior. 7383** 7384** The sqlite3_keyword_check(Z,L) interface checks to see whether or not 7385** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero 7386** if it is and zero if not. 7387** 7388** The parser used by SQLite is forgiving. It is often possible to use 7389** a keyword as an identifier as long as such use does not result in a 7390** parsing ambiguity. For example, the statement 7391** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and 7392** creates a new table named "BEGIN" with three columns named 7393** "REPLACE", "PRAGMA", and "END". Nevertheless, best practice is to avoid 7394** using keywords as identifiers. Common techniques used to avoid keyword 7395** name collisions include: 7396** <ul> 7397** <li> Put all identifier names inside double-quotes. This is the official 7398** SQL way to escape identifier names. 7399** <li> Put identifier names inside [...]. This is not standard SQL, 7400** but it is what SQL Server does and so lots of programmers use this 7401** technique. 7402** <li> Begin every identifier with the letter "Z" as no SQL keywords start 7403** with "Z". 7404** <li> Include a digit somewhere in every identifier name. 7405** </ul> 7406** 7407** Note that the number of keywords understood by SQLite can depend on 7408** compile-time options. For example, "VACUUM" is not a keyword if 7409** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option. Also, 7410** new keywords may be added to future releases of SQLite. 7411*/ 7412int sqlite3_keyword_count(void); 7413int sqlite3_keyword_name(int,const char**,int*); 7414int sqlite3_keyword_check(const char*,int); 7415 7416/* 7417** CAPI3REF: Dynamic String Object 7418** KEYWORDS: {dynamic string} 7419** 7420** An instance of the sqlite3_str object contains a dynamically-sized 7421** string under construction. 7422** 7423** The lifecycle of an sqlite3_str object is as follows: 7424** <ol> 7425** <li> ^The sqlite3_str object is created using [sqlite3_str_new()]. 7426** <li> ^Text is appended to the sqlite3_str object using various 7427** methods, such as [sqlite3_str_appendf()]. 7428** <li> ^The sqlite3_str object is destroyed and the string it created 7429** is returned using the [sqlite3_str_finish()] interface. 7430** </ol> 7431*/ 7432typedef struct sqlite3_str sqlite3_str; 7433 7434/* 7435** CAPI3REF: Create A New Dynamic String Object 7436** CONSTRUCTOR: sqlite3_str 7437** 7438** ^The [sqlite3_str_new(D)] interface allocates and initializes 7439** a new [sqlite3_str] object. To avoid memory leaks, the object returned by 7440** [sqlite3_str_new()] must be freed by a subsequent call to 7441** [sqlite3_str_finish(X)]. 7442** 7443** ^The [sqlite3_str_new(D)] interface always returns a pointer to a 7444** valid [sqlite3_str] object, though in the event of an out-of-memory 7445** error the returned object might be a special singleton that will 7446** silently reject new text, always return SQLITE_NOMEM from 7447** [sqlite3_str_errcode()], always return 0 for 7448** [sqlite3_str_length()], and always return NULL from 7449** [sqlite3_str_finish(X)]. It is always safe to use the value 7450** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter 7451** to any of the other [sqlite3_str] methods. 7452** 7453** The D parameter to [sqlite3_str_new(D)] may be NULL. If the 7454** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum 7455** length of the string contained in the [sqlite3_str] object will be 7456** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead 7457** of [SQLITE_MAX_LENGTH]. 7458*/ 7459sqlite3_str *sqlite3_str_new(sqlite3*); 7460 7461/* 7462** CAPI3REF: Finalize A Dynamic String 7463** DESTRUCTOR: sqlite3_str 7464** 7465** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X 7466** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()] 7467** that contains the constructed string. The calling application should 7468** pass the returned value to [sqlite3_free()] to avoid a memory leak. 7469** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any 7470** errors were encountered during construction of the string. ^The 7471** [sqlite3_str_finish(X)] interface will also return a NULL pointer if the 7472** string in [sqlite3_str] object X is zero bytes long. 7473*/ 7474char *sqlite3_str_finish(sqlite3_str*); 7475 7476/* 7477** CAPI3REF: Add Content To A Dynamic String 7478** METHOD: sqlite3_str 7479** 7480** These interfaces add content to an sqlite3_str object previously obtained 7481** from [sqlite3_str_new()]. 7482** 7483** ^The [sqlite3_str_appendf(X,F,...)] and 7484** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf] 7485** functionality of SQLite to append formatted text onto the end of 7486** [sqlite3_str] object X. 7487** 7488** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S 7489** onto the end of the [sqlite3_str] object X. N must be non-negative. 7490** S must contain at least N non-zero bytes of content. To append a 7491** zero-terminated string in its entirety, use the [sqlite3_str_appendall()] 7492** method instead. 7493** 7494** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of 7495** zero-terminated string S onto the end of [sqlite3_str] object X. 7496** 7497** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the 7498** single-byte character C onto the end of [sqlite3_str] object X. 7499** ^This method can be used, for example, to add whitespace indentation. 7500** 7501** ^The [sqlite3_str_reset(X)] method resets the string under construction 7502** inside [sqlite3_str] object X back to zero bytes in length. 7503** 7504** These methods do not return a result code. ^If an error occurs, that fact 7505** is recorded in the [sqlite3_str] object and can be recovered by a 7506** subsequent call to [sqlite3_str_errcode(X)]. 7507*/ 7508void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...); 7509void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list); 7510void sqlite3_str_append(sqlite3_str*, const char *zIn, int N); 7511void sqlite3_str_appendall(sqlite3_str*, const char *zIn); 7512void sqlite3_str_appendchar(sqlite3_str*, int N, char C); 7513void sqlite3_str_reset(sqlite3_str*); 7514 7515/* 7516** CAPI3REF: Status Of A Dynamic String 7517** METHOD: sqlite3_str 7518** 7519** These interfaces return the current status of an [sqlite3_str] object. 7520** 7521** ^If any prior errors have occurred while constructing the dynamic string 7522** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return 7523** an appropriate error code. ^The [sqlite3_str_errcode(X)] method returns 7524** [SQLITE_NOMEM] following any out-of-memory error, or 7525** [SQLITE_TOOBIG] if the size of the dynamic string exceeds 7526** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors. 7527** 7528** ^The [sqlite3_str_length(X)] method returns the current length, in bytes, 7529** of the dynamic string under construction in [sqlite3_str] object X. 7530** ^The length returned by [sqlite3_str_length(X)] does not include the 7531** zero-termination byte. 7532** 7533** ^The [sqlite3_str_value(X)] method returns a pointer to the current 7534** content of the dynamic string under construction in X. The value 7535** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X 7536** and might be freed or altered by any subsequent method on the same 7537** [sqlite3_str] object. Applications must not used the pointer returned 7538** [sqlite3_str_value(X)] after any subsequent method call on the same 7539** object. ^Applications may change the content of the string returned 7540** by [sqlite3_str_value(X)] as long as they do not write into any bytes 7541** outside the range of 0 to [sqlite3_str_length(X)] and do not read or 7542** write any byte after any subsequent sqlite3_str method call. 7543*/ 7544int sqlite3_str_errcode(sqlite3_str*); 7545int sqlite3_str_length(sqlite3_str*); 7546char *sqlite3_str_value(sqlite3_str*); 7547 7548/* 7549** CAPI3REF: SQLite Runtime Status 7550** 7551** ^These interfaces are used to retrieve runtime status information 7552** about the performance of SQLite, and optionally to reset various 7553** highwater marks. ^The first argument is an integer code for 7554** the specific parameter to measure. ^(Recognized integer codes 7555** are of the form [status parameters | SQLITE_STATUS_...].)^ 7556** ^The current value of the parameter is returned into *pCurrent. 7557** ^The highest recorded value is returned in *pHighwater. ^If the 7558** resetFlag is true, then the highest record value is reset after 7559** *pHighwater is written. ^(Some parameters do not record the highest 7560** value. For those parameters 7561** nothing is written into *pHighwater and the resetFlag is ignored.)^ 7562** ^(Other parameters record only the highwater mark and not the current 7563** value. For these latter parameters nothing is written into *pCurrent.)^ 7564** 7565** ^The sqlite3_status() and sqlite3_status64() routines return 7566** SQLITE_OK on success and a non-zero [error code] on failure. 7567** 7568** If either the current value or the highwater mark is too large to 7569** be represented by a 32-bit integer, then the values returned by 7570** sqlite3_status() are undefined. 7571** 7572** See also: [sqlite3_db_status()] 7573*/ 7574int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 7575int sqlite3_status64( 7576 int op, 7577 sqlite3_int64 *pCurrent, 7578 sqlite3_int64 *pHighwater, 7579 int resetFlag 7580); 7581 7582 7583/* 7584** CAPI3REF: Status Parameters 7585** KEYWORDS: {status parameters} 7586** 7587** These integer constants designate various run-time status parameters 7588** that can be returned by [sqlite3_status()]. 7589** 7590** <dl> 7591** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 7592** <dd>This parameter is the current amount of memory checked out 7593** using [sqlite3_malloc()], either directly or indirectly. The 7594** figure includes calls made to [sqlite3_malloc()] by the application 7595** and internal memory usage by the SQLite library. Auxiliary page-cache 7596** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 7597** this parameter. The amount returned is the sum of the allocation 7598** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 7599** 7600** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 7601** <dd>This parameter records the largest memory allocation request 7602** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 7603** internal equivalents). Only the value returned in the 7604** *pHighwater parameter to [sqlite3_status()] is of interest. 7605** The value written into the *pCurrent parameter is undefined.</dd>)^ 7606** 7607** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 7608** <dd>This parameter records the number of separate memory allocations 7609** currently checked out.</dd>)^ 7610** 7611** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 7612** <dd>This parameter returns the number of pages used out of the 7613** [pagecache memory allocator] that was configured using 7614** [SQLITE_CONFIG_PAGECACHE]. The 7615** value returned is in pages, not in bytes.</dd>)^ 7616** 7617** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 7618** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 7619** <dd>This parameter returns the number of bytes of page cache 7620** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 7621** buffer and where forced to overflow to [sqlite3_malloc()]. The 7622** returned value includes allocations that overflowed because they 7623** where too large (they were larger than the "sz" parameter to 7624** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 7625** no space was left in the page cache.</dd>)^ 7626** 7627** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 7628** <dd>This parameter records the largest memory allocation request 7629** handed to [pagecache memory allocator]. Only the value returned in the 7630** *pHighwater parameter to [sqlite3_status()] is of interest. 7631** The value written into the *pCurrent parameter is undefined.</dd>)^ 7632** 7633** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt> 7634** <dd>No longer used.</dd> 7635** 7636** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 7637** <dd>No longer used.</dd> 7638** 7639** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 7640** <dd>No longer used.</dd> 7641** 7642** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 7643** <dd>The *pHighwater parameter records the deepest parser stack. 7644** The *pCurrent value is undefined. The *pHighwater value is only 7645** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 7646** </dl> 7647** 7648** New status parameters may be added from time to time. 7649*/ 7650#define SQLITE_STATUS_MEMORY_USED 0 7651#define SQLITE_STATUS_PAGECACHE_USED 1 7652#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 7653#define SQLITE_STATUS_SCRATCH_USED 3 /* NOT USED */ 7654#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 /* NOT USED */ 7655#define SQLITE_STATUS_MALLOC_SIZE 5 7656#define SQLITE_STATUS_PARSER_STACK 6 7657#define SQLITE_STATUS_PAGECACHE_SIZE 7 7658#define SQLITE_STATUS_SCRATCH_SIZE 8 /* NOT USED */ 7659#define SQLITE_STATUS_MALLOC_COUNT 9 7660 7661/* 7662** CAPI3REF: Database Connection Status 7663** METHOD: sqlite3 7664** 7665** ^This interface is used to retrieve runtime status information 7666** about a single [database connection]. ^The first argument is the 7667** database connection object to be interrogated. ^The second argument 7668** is an integer constant, taken from the set of 7669** [SQLITE_DBSTATUS options], that 7670** determines the parameter to interrogate. The set of 7671** [SQLITE_DBSTATUS options] is likely 7672** to grow in future releases of SQLite. 7673** 7674** ^The current value of the requested parameter is written into *pCur 7675** and the highest instantaneous value is written into *pHiwtr. ^If 7676** the resetFlg is true, then the highest instantaneous value is 7677** reset back down to the current value. 7678** 7679** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 7680** non-zero [error code] on failure. 7681** 7682** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 7683*/ 7684int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 7685 7686/* 7687** CAPI3REF: Status Parameters for database connections 7688** KEYWORDS: {SQLITE_DBSTATUS options} 7689** 7690** These constants are the available integer "verbs" that can be passed as 7691** the second argument to the [sqlite3_db_status()] interface. 7692** 7693** New verbs may be added in future releases of SQLite. Existing verbs 7694** might be discontinued. Applications should check the return code from 7695** [sqlite3_db_status()] to make sure that the call worked. 7696** The [sqlite3_db_status()] interface will return a non-zero error code 7697** if a discontinued or unsupported verb is invoked. 7698** 7699** <dl> 7700** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 7701** <dd>This parameter returns the number of lookaside memory slots currently 7702** checked out.</dd>)^ 7703** 7704** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 7705** <dd>This parameter returns the number malloc attempts that were 7706** satisfied using lookaside memory. Only the high-water value is meaningful; 7707** the current value is always zero.)^ 7708** 7709** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 7710** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 7711** <dd>This parameter returns the number malloc attempts that might have 7712** been satisfied using lookaside memory but failed due to the amount of 7713** memory requested being larger than the lookaside slot size. 7714** Only the high-water value is meaningful; 7715** the current value is always zero.)^ 7716** 7717** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 7718** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 7719** <dd>This parameter returns the number malloc attempts that might have 7720** been satisfied using lookaside memory but failed due to all lookaside 7721** memory already being in use. 7722** Only the high-water value is meaningful; 7723** the current value is always zero.)^ 7724** 7725** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 7726** <dd>This parameter returns the approximate number of bytes of heap 7727** memory used by all pager caches associated with the database connection.)^ 7728** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 7729** 7730** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 7731** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt> 7732** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a 7733** pager cache is shared between two or more connections the bytes of heap 7734** memory used by that pager cache is divided evenly between the attached 7735** connections.)^ In other words, if none of the pager caches associated 7736** with the database connection are shared, this request returns the same 7737** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are 7738** shared, the value returned by this call will be smaller than that returned 7739** by DBSTATUS_CACHE_USED. ^The highwater mark associated with 7740** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0. 7741** 7742** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 7743** <dd>This parameter returns the approximate number of bytes of heap 7744** memory used to store the schema for all databases associated 7745** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 7746** ^The full amount of memory used by the schemas is reported, even if the 7747** schema memory is shared with other database connections due to 7748** [shared cache mode] being enabled. 7749** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 7750** 7751** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 7752** <dd>This parameter returns the approximate number of bytes of heap 7753** and lookaside memory used by all prepared statements associated with 7754** the database connection.)^ 7755** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 7756** </dd> 7757** 7758** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 7759** <dd>This parameter returns the number of pager cache hits that have 7760** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 7761** is always 0. 7762** </dd> 7763** 7764** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 7765** <dd>This parameter returns the number of pager cache misses that have 7766** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 7767** is always 0. 7768** </dd> 7769** 7770** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt> 7771** <dd>This parameter returns the number of dirty cache entries that have 7772** been written to disk. Specifically, the number of pages written to the 7773** wal file in wal mode databases, or the number of pages written to the 7774** database file in rollback mode databases. Any pages written as part of 7775** transaction rollback or database recovery operations are not included. 7776** If an IO or other error occurs while writing a page to disk, the effect 7777** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The 7778** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0. 7779** </dd> 7780** 7781** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt> 7782** <dd>This parameter returns the number of dirty cache entries that have 7783** been written to disk in the middle of a transaction due to the page 7784** cache overflowing. Transactions are more efficient if they are written 7785** to disk all at once. When pages spill mid-transaction, that introduces 7786** additional overhead. This parameter can be used help identify 7787** inefficiencies that can be resolve by increasing the cache size. 7788** </dd> 7789** 7790** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt> 7791** <dd>This parameter returns zero for the current value if and only if 7792** all foreign key constraints (deferred or immediate) have been 7793** resolved.)^ ^The highwater mark is always 0. 7794** </dd> 7795** </dl> 7796*/ 7797#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 7798#define SQLITE_DBSTATUS_CACHE_USED 1 7799#define SQLITE_DBSTATUS_SCHEMA_USED 2 7800#define SQLITE_DBSTATUS_STMT_USED 3 7801#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 7802#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 7803#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 7804#define SQLITE_DBSTATUS_CACHE_HIT 7 7805#define SQLITE_DBSTATUS_CACHE_MISS 8 7806#define SQLITE_DBSTATUS_CACHE_WRITE 9 7807#define SQLITE_DBSTATUS_DEFERRED_FKS 10 7808#define SQLITE_DBSTATUS_CACHE_USED_SHARED 11 7809#define SQLITE_DBSTATUS_CACHE_SPILL 12 7810#define SQLITE_DBSTATUS_MAX 12 /* Largest defined DBSTATUS */ 7811 7812 7813/* 7814** CAPI3REF: Prepared Statement Status 7815** METHOD: sqlite3_stmt 7816** 7817** ^(Each prepared statement maintains various 7818** [SQLITE_STMTSTATUS counters] that measure the number 7819** of times it has performed specific operations.)^ These counters can 7820** be used to monitor the performance characteristics of the prepared 7821** statements. For example, if the number of table steps greatly exceeds 7822** the number of table searches or result rows, that would tend to indicate 7823** that the prepared statement is using a full table scan rather than 7824** an index. 7825** 7826** ^(This interface is used to retrieve and reset counter values from 7827** a [prepared statement]. The first argument is the prepared statement 7828** object to be interrogated. The second argument 7829** is an integer code for a specific [SQLITE_STMTSTATUS counter] 7830** to be interrogated.)^ 7831** ^The current value of the requested counter is returned. 7832** ^If the resetFlg is true, then the counter is reset to zero after this 7833** interface call returns. 7834** 7835** See also: [sqlite3_status()] and [sqlite3_db_status()]. 7836*/ 7837int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 7838 7839/* 7840** CAPI3REF: Status Parameters for prepared statements 7841** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 7842** 7843** These preprocessor macros define integer codes that name counter 7844** values associated with the [sqlite3_stmt_status()] interface. 7845** The meanings of the various counters are as follows: 7846** 7847** <dl> 7848** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 7849** <dd>^This is the number of times that SQLite has stepped forward in 7850** a table as part of a full table scan. Large numbers for this counter 7851** may indicate opportunities for performance improvement through 7852** careful use of indices.</dd> 7853** 7854** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 7855** <dd>^This is the number of sort operations that have occurred. 7856** A non-zero value in this counter may indicate an opportunity to 7857** improvement performance through careful use of indices.</dd> 7858** 7859** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 7860** <dd>^This is the number of rows inserted into transient indices that 7861** were created automatically in order to help joins run faster. 7862** A non-zero value in this counter may indicate an opportunity to 7863** improvement performance by adding permanent indices that do not 7864** need to be reinitialized each time the statement is run.</dd> 7865** 7866** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt> 7867** <dd>^This is the number of virtual machine operations executed 7868** by the prepared statement if that number is less than or equal 7869** to 2147483647. The number of virtual machine operations can be 7870** used as a proxy for the total work done by the prepared statement. 7871** If the number of virtual machine operations exceeds 2147483647 7872** then the value returned by this statement status code is undefined. 7873** 7874** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt> 7875** <dd>^This is the number of times that the prepare statement has been 7876** automatically regenerated due to schema changes or change to 7877** [bound parameters] that might affect the query plan. 7878** 7879** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt> 7880** <dd>^This is the number of times that the prepared statement has 7881** been run. A single "run" for the purposes of this counter is one 7882** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()]. 7883** The counter is incremented on the first [sqlite3_step()] call of each 7884** cycle. 7885** 7886** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt> 7887** <dd>^This is the approximate number of bytes of heap memory 7888** used to store the prepared statement. ^This value is not actually 7889** a counter, and so the resetFlg parameter to sqlite3_stmt_status() 7890** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED. 7891** </dd> 7892** </dl> 7893*/ 7894#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 7895#define SQLITE_STMTSTATUS_SORT 2 7896#define SQLITE_STMTSTATUS_AUTOINDEX 3 7897#define SQLITE_STMTSTATUS_VM_STEP 4 7898#define SQLITE_STMTSTATUS_REPREPARE 5 7899#define SQLITE_STMTSTATUS_RUN 6 7900#define SQLITE_STMTSTATUS_MEMUSED 99 7901 7902/* 7903** CAPI3REF: Custom Page Cache Object 7904** 7905** The sqlite3_pcache type is opaque. It is implemented by 7906** the pluggable module. The SQLite core has no knowledge of 7907** its size or internal structure and never deals with the 7908** sqlite3_pcache object except by holding and passing pointers 7909** to the object. 7910** 7911** See [sqlite3_pcache_methods2] for additional information. 7912*/ 7913typedef struct sqlite3_pcache sqlite3_pcache; 7914 7915/* 7916** CAPI3REF: Custom Page Cache Object 7917** 7918** The sqlite3_pcache_page object represents a single page in the 7919** page cache. The page cache will allocate instances of this 7920** object. Various methods of the page cache use pointers to instances 7921** of this object as parameters or as their return value. 7922** 7923** See [sqlite3_pcache_methods2] for additional information. 7924*/ 7925typedef struct sqlite3_pcache_page sqlite3_pcache_page; 7926struct sqlite3_pcache_page { 7927 void *pBuf; /* The content of the page */ 7928 void *pExtra; /* Extra information associated with the page */ 7929}; 7930 7931/* 7932** CAPI3REF: Application Defined Page Cache. 7933** KEYWORDS: {page cache} 7934** 7935** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 7936** register an alternative page cache implementation by passing in an 7937** instance of the sqlite3_pcache_methods2 structure.)^ 7938** In many applications, most of the heap memory allocated by 7939** SQLite is used for the page cache. 7940** By implementing a 7941** custom page cache using this API, an application can better control 7942** the amount of memory consumed by SQLite, the way in which 7943** that memory is allocated and released, and the policies used to 7944** determine exactly which parts of a database file are cached and for 7945** how long. 7946** 7947** The alternative page cache mechanism is an 7948** extreme measure that is only needed by the most demanding applications. 7949** The built-in page cache is recommended for most uses. 7950** 7951** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 7952** internal buffer by SQLite within the call to [sqlite3_config]. Hence 7953** the application may discard the parameter after the call to 7954** [sqlite3_config()] returns.)^ 7955** 7956** [[the xInit() page cache method]] 7957** ^(The xInit() method is called once for each effective 7958** call to [sqlite3_initialize()])^ 7959** (usually only once during the lifetime of the process). ^(The xInit() 7960** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 7961** The intent of the xInit() method is to set up global data structures 7962** required by the custom page cache implementation. 7963** ^(If the xInit() method is NULL, then the 7964** built-in default page cache is used instead of the application defined 7965** page cache.)^ 7966** 7967** [[the xShutdown() page cache method]] 7968** ^The xShutdown() method is called by [sqlite3_shutdown()]. 7969** It can be used to clean up 7970** any outstanding resources before process shutdown, if required. 7971** ^The xShutdown() method may be NULL. 7972** 7973** ^SQLite automatically serializes calls to the xInit method, 7974** so the xInit method need not be threadsafe. ^The 7975** xShutdown method is only called from [sqlite3_shutdown()] so it does 7976** not need to be threadsafe either. All other methods must be threadsafe 7977** in multithreaded applications. 7978** 7979** ^SQLite will never invoke xInit() more than once without an intervening 7980** call to xShutdown(). 7981** 7982** [[the xCreate() page cache methods]] 7983** ^SQLite invokes the xCreate() method to construct a new cache instance. 7984** SQLite will typically create one cache instance for each open database file, 7985** though this is not guaranteed. ^The 7986** first parameter, szPage, is the size in bytes of the pages that must 7987** be allocated by the cache. ^szPage will always a power of two. ^The 7988** second parameter szExtra is a number of bytes of extra storage 7989** associated with each page cache entry. ^The szExtra parameter will 7990** a number less than 250. SQLite will use the 7991** extra szExtra bytes on each page to store metadata about the underlying 7992** database page on disk. The value passed into szExtra depends 7993** on the SQLite version, the target platform, and how SQLite was compiled. 7994** ^The third argument to xCreate(), bPurgeable, is true if the cache being 7995** created will be used to cache database pages of a file stored on disk, or 7996** false if it is used for an in-memory database. The cache implementation 7997** does not have to do anything special based with the value of bPurgeable; 7998** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 7999** never invoke xUnpin() except to deliberately delete a page. 8000** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 8001** false will always have the "discard" flag set to true. 8002** ^Hence, a cache created with bPurgeable false will 8003** never contain any unpinned pages. 8004** 8005** [[the xCachesize() page cache method]] 8006** ^(The xCachesize() method may be called at any time by SQLite to set the 8007** suggested maximum cache-size (number of pages stored by) the cache 8008** instance passed as the first argument. This is the value configured using 8009** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 8010** parameter, the implementation is not required to do anything with this 8011** value; it is advisory only. 8012** 8013** [[the xPagecount() page cache methods]] 8014** The xPagecount() method must return the number of pages currently 8015** stored in the cache, both pinned and unpinned. 8016** 8017** [[the xFetch() page cache methods]] 8018** The xFetch() method locates a page in the cache and returns a pointer to 8019** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 8020** The pBuf element of the returned sqlite3_pcache_page object will be a 8021** pointer to a buffer of szPage bytes used to store the content of a 8022** single database page. The pExtra element of sqlite3_pcache_page will be 8023** a pointer to the szExtra bytes of extra storage that SQLite has requested 8024** for each entry in the page cache. 8025** 8026** The page to be fetched is determined by the key. ^The minimum key value 8027** is 1. After it has been retrieved using xFetch, the page is considered 8028** to be "pinned". 8029** 8030** If the requested page is already in the page cache, then the page cache 8031** implementation must return a pointer to the page buffer with its content 8032** intact. If the requested page is not already in the cache, then the 8033** cache implementation should use the value of the createFlag 8034** parameter to help it determined what action to take: 8035** 8036** <table border=1 width=85% align=center> 8037** <tr><th> createFlag <th> Behavior when page is not already in cache 8038** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 8039** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 8040** Otherwise return NULL. 8041** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 8042** NULL if allocating a new page is effectively impossible. 8043** </table> 8044** 8045** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 8046** will only use a createFlag of 2 after a prior call with a createFlag of 1 8047** failed.)^ In between the to xFetch() calls, SQLite may 8048** attempt to unpin one or more cache pages by spilling the content of 8049** pinned pages to disk and synching the operating system disk cache. 8050** 8051** [[the xUnpin() page cache method]] 8052** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 8053** as its second argument. If the third parameter, discard, is non-zero, 8054** then the page must be evicted from the cache. 8055** ^If the discard parameter is 8056** zero, then the page may be discarded or retained at the discretion of 8057** page cache implementation. ^The page cache implementation 8058** may choose to evict unpinned pages at any time. 8059** 8060** The cache must not perform any reference counting. A single 8061** call to xUnpin() unpins the page regardless of the number of prior calls 8062** to xFetch(). 8063** 8064** [[the xRekey() page cache methods]] 8065** The xRekey() method is used to change the key value associated with the 8066** page passed as the second argument. If the cache 8067** previously contains an entry associated with newKey, it must be 8068** discarded. ^Any prior cache entry associated with newKey is guaranteed not 8069** to be pinned. 8070** 8071** When SQLite calls the xTruncate() method, the cache must discard all 8072** existing cache entries with page numbers (keys) greater than or equal 8073** to the value of the iLimit parameter passed to xTruncate(). If any 8074** of these pages are pinned, they are implicitly unpinned, meaning that 8075** they can be safely discarded. 8076** 8077** [[the xDestroy() page cache method]] 8078** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 8079** All resources associated with the specified cache should be freed. ^After 8080** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 8081** handle invalid, and will not use it with any other sqlite3_pcache_methods2 8082** functions. 8083** 8084** [[the xShrink() page cache method]] 8085** ^SQLite invokes the xShrink() method when it wants the page cache to 8086** free up as much of heap memory as possible. The page cache implementation 8087** is not obligated to free any memory, but well-behaved implementations should 8088** do their best. 8089*/ 8090typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 8091struct sqlite3_pcache_methods2 { 8092 int iVersion; 8093 void *pArg; 8094 int (*xInit)(void*); 8095 void (*xShutdown)(void*); 8096 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 8097 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8098 int (*xPagecount)(sqlite3_pcache*); 8099 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8100 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 8101 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 8102 unsigned oldKey, unsigned newKey); 8103 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8104 void (*xDestroy)(sqlite3_pcache*); 8105 void (*xShrink)(sqlite3_pcache*); 8106}; 8107 8108/* 8109** This is the obsolete pcache_methods object that has now been replaced 8110** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 8111** retained in the header file for backwards compatibility only. 8112*/ 8113typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 8114struct sqlite3_pcache_methods { 8115 void *pArg; 8116 int (*xInit)(void*); 8117 void (*xShutdown)(void*); 8118 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 8119 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 8120 int (*xPagecount)(sqlite3_pcache*); 8121 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 8122 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 8123 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 8124 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 8125 void (*xDestroy)(sqlite3_pcache*); 8126}; 8127 8128 8129/* 8130** CAPI3REF: Online Backup Object 8131** 8132** The sqlite3_backup object records state information about an ongoing 8133** online backup operation. ^The sqlite3_backup object is created by 8134** a call to [sqlite3_backup_init()] and is destroyed by a call to 8135** [sqlite3_backup_finish()]. 8136** 8137** See Also: [Using the SQLite Online Backup API] 8138*/ 8139typedef struct sqlite3_backup sqlite3_backup; 8140 8141/* 8142** CAPI3REF: Online Backup API. 8143** 8144** The backup API copies the content of one database into another. 8145** It is useful either for creating backups of databases or 8146** for copying in-memory databases to or from persistent files. 8147** 8148** See Also: [Using the SQLite Online Backup API] 8149** 8150** ^SQLite holds a write transaction open on the destination database file 8151** for the duration of the backup operation. 8152** ^The source database is read-locked only while it is being read; 8153** it is not locked continuously for the entire backup operation. 8154** ^Thus, the backup may be performed on a live source database without 8155** preventing other database connections from 8156** reading or writing to the source database while the backup is underway. 8157** 8158** ^(To perform a backup operation: 8159** <ol> 8160** <li><b>sqlite3_backup_init()</b> is called once to initialize the 8161** backup, 8162** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 8163** the data between the two databases, and finally 8164** <li><b>sqlite3_backup_finish()</b> is called to release all resources 8165** associated with the backup operation. 8166** </ol>)^ 8167** There should be exactly one call to sqlite3_backup_finish() for each 8168** successful call to sqlite3_backup_init(). 8169** 8170** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 8171** 8172** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 8173** [database connection] associated with the destination database 8174** and the database name, respectively. 8175** ^The database name is "main" for the main database, "temp" for the 8176** temporary database, or the name specified after the AS keyword in 8177** an [ATTACH] statement for an attached database. 8178** ^The S and M arguments passed to 8179** sqlite3_backup_init(D,N,S,M) identify the [database connection] 8180** and database name of the source database, respectively. 8181** ^The source and destination [database connections] (parameters S and D) 8182** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 8183** an error. 8184** 8185** ^A call to sqlite3_backup_init() will fail, returning NULL, if 8186** there is already a read or read-write transaction open on the 8187** destination database. 8188** 8189** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 8190** returned and an error code and error message are stored in the 8191** destination [database connection] D. 8192** ^The error code and message for the failed call to sqlite3_backup_init() 8193** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 8194** [sqlite3_errmsg16()] functions. 8195** ^A successful call to sqlite3_backup_init() returns a pointer to an 8196** [sqlite3_backup] object. 8197** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 8198** sqlite3_backup_finish() functions to perform the specified backup 8199** operation. 8200** 8201** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 8202** 8203** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 8204** the source and destination databases specified by [sqlite3_backup] object B. 8205** ^If N is negative, all remaining source pages are copied. 8206** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 8207** are still more pages to be copied, then the function returns [SQLITE_OK]. 8208** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 8209** from source to destination, then it returns [SQLITE_DONE]. 8210** ^If an error occurs while running sqlite3_backup_step(B,N), 8211** then an [error code] is returned. ^As well as [SQLITE_OK] and 8212** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 8213** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 8214** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 8215** 8216** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 8217** <ol> 8218** <li> the destination database was opened read-only, or 8219** <li> the destination database is using write-ahead-log journaling 8220** and the destination and source page sizes differ, or 8221** <li> the destination database is an in-memory database and the 8222** destination and source page sizes differ. 8223** </ol>)^ 8224** 8225** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 8226** the [sqlite3_busy_handler | busy-handler function] 8227** is invoked (if one is specified). ^If the 8228** busy-handler returns non-zero before the lock is available, then 8229** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 8230** sqlite3_backup_step() can be retried later. ^If the source 8231** [database connection] 8232** is being used to write to the source database when sqlite3_backup_step() 8233** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 8234** case the call to sqlite3_backup_step() can be retried later on. ^(If 8235** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 8236** [SQLITE_READONLY] is returned, then 8237** there is no point in retrying the call to sqlite3_backup_step(). These 8238** errors are considered fatal.)^ The application must accept 8239** that the backup operation has failed and pass the backup operation handle 8240** to the sqlite3_backup_finish() to release associated resources. 8241** 8242** ^The first call to sqlite3_backup_step() obtains an exclusive lock 8243** on the destination file. ^The exclusive lock is not released until either 8244** sqlite3_backup_finish() is called or the backup operation is complete 8245** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 8246** sqlite3_backup_step() obtains a [shared lock] on the source database that 8247** lasts for the duration of the sqlite3_backup_step() call. 8248** ^Because the source database is not locked between calls to 8249** sqlite3_backup_step(), the source database may be modified mid-way 8250** through the backup process. ^If the source database is modified by an 8251** external process or via a database connection other than the one being 8252** used by the backup operation, then the backup will be automatically 8253** restarted by the next call to sqlite3_backup_step(). ^If the source 8254** database is modified by the using the same database connection as is used 8255** by the backup operation, then the backup database is automatically 8256** updated at the same time. 8257** 8258** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 8259** 8260** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 8261** application wishes to abandon the backup operation, the application 8262** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 8263** ^The sqlite3_backup_finish() interfaces releases all 8264** resources associated with the [sqlite3_backup] object. 8265** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 8266** active write-transaction on the destination database is rolled back. 8267** The [sqlite3_backup] object is invalid 8268** and may not be used following a call to sqlite3_backup_finish(). 8269** 8270** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 8271** sqlite3_backup_step() errors occurred, regardless or whether or not 8272** sqlite3_backup_step() completed. 8273** ^If an out-of-memory condition or IO error occurred during any prior 8274** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 8275** sqlite3_backup_finish() returns the corresponding [error code]. 8276** 8277** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 8278** is not a permanent error and does not affect the return value of 8279** sqlite3_backup_finish(). 8280** 8281** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]] 8282** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 8283** 8284** ^The sqlite3_backup_remaining() routine returns the number of pages still 8285** to be backed up at the conclusion of the most recent sqlite3_backup_step(). 8286** ^The sqlite3_backup_pagecount() routine returns the total number of pages 8287** in the source database at the conclusion of the most recent 8288** sqlite3_backup_step(). 8289** ^(The values returned by these functions are only updated by 8290** sqlite3_backup_step(). If the source database is modified in a way that 8291** changes the size of the source database or the number of pages remaining, 8292** those changes are not reflected in the output of sqlite3_backup_pagecount() 8293** and sqlite3_backup_remaining() until after the next 8294** sqlite3_backup_step().)^ 8295** 8296** <b>Concurrent Usage of Database Handles</b> 8297** 8298** ^The source [database connection] may be used by the application for other 8299** purposes while a backup operation is underway or being initialized. 8300** ^If SQLite is compiled and configured to support threadsafe database 8301** connections, then the source database connection may be used concurrently 8302** from within other threads. 8303** 8304** However, the application must guarantee that the destination 8305** [database connection] is not passed to any other API (by any thread) after 8306** sqlite3_backup_init() is called and before the corresponding call to 8307** sqlite3_backup_finish(). SQLite does not currently check to see 8308** if the application incorrectly accesses the destination [database connection] 8309** and so no error code is reported, but the operations may malfunction 8310** nevertheless. Use of the destination database connection while a 8311** backup is in progress might also also cause a mutex deadlock. 8312** 8313** If running in [shared cache mode], the application must 8314** guarantee that the shared cache used by the destination database 8315** is not accessed while the backup is running. In practice this means 8316** that the application must guarantee that the disk file being 8317** backed up to is not accessed by any connection within the process, 8318** not just the specific connection that was passed to sqlite3_backup_init(). 8319** 8320** The [sqlite3_backup] object itself is partially threadsafe. Multiple 8321** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 8322** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 8323** APIs are not strictly speaking threadsafe. If they are invoked at the 8324** same time as another thread is invoking sqlite3_backup_step() it is 8325** possible that they return invalid values. 8326*/ 8327sqlite3_backup *sqlite3_backup_init( 8328 sqlite3 *pDest, /* Destination database handle */ 8329 const char *zDestName, /* Destination database name */ 8330 sqlite3 *pSource, /* Source database handle */ 8331 const char *zSourceName /* Source database name */ 8332); 8333int sqlite3_backup_step(sqlite3_backup *p, int nPage); 8334int sqlite3_backup_finish(sqlite3_backup *p); 8335int sqlite3_backup_remaining(sqlite3_backup *p); 8336int sqlite3_backup_pagecount(sqlite3_backup *p); 8337 8338/* 8339** CAPI3REF: Unlock Notification 8340** METHOD: sqlite3 8341** 8342** ^When running in shared-cache mode, a database operation may fail with 8343** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 8344** individual tables within the shared-cache cannot be obtained. See 8345** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 8346** ^This API may be used to register a callback that SQLite will invoke 8347** when the connection currently holding the required lock relinquishes it. 8348** ^This API is only available if the library was compiled with the 8349** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 8350** 8351** See Also: [Using the SQLite Unlock Notification Feature]. 8352** 8353** ^Shared-cache locks are released when a database connection concludes 8354** its current transaction, either by committing it or rolling it back. 8355** 8356** ^When a connection (known as the blocked connection) fails to obtain a 8357** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 8358** identity of the database connection (the blocking connection) that 8359** has locked the required resource is stored internally. ^After an 8360** application receives an SQLITE_LOCKED error, it may call the 8361** sqlite3_unlock_notify() method with the blocked connection handle as 8362** the first argument to register for a callback that will be invoked 8363** when the blocking connections current transaction is concluded. ^The 8364** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 8365** call that concludes the blocking connections transaction. 8366** 8367** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 8368** there is a chance that the blocking connection will have already 8369** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 8370** If this happens, then the specified callback is invoked immediately, 8371** from within the call to sqlite3_unlock_notify().)^ 8372** 8373** ^If the blocked connection is attempting to obtain a write-lock on a 8374** shared-cache table, and more than one other connection currently holds 8375** a read-lock on the same table, then SQLite arbitrarily selects one of 8376** the other connections to use as the blocking connection. 8377** 8378** ^(There may be at most one unlock-notify callback registered by a 8379** blocked connection. If sqlite3_unlock_notify() is called when the 8380** blocked connection already has a registered unlock-notify callback, 8381** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 8382** called with a NULL pointer as its second argument, then any existing 8383** unlock-notify callback is canceled. ^The blocked connections 8384** unlock-notify callback may also be canceled by closing the blocked 8385** connection using [sqlite3_close()]. 8386** 8387** The unlock-notify callback is not reentrant. If an application invokes 8388** any sqlite3_xxx API functions from within an unlock-notify callback, a 8389** crash or deadlock may be the result. 8390** 8391** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 8392** returns SQLITE_OK. 8393** 8394** <b>Callback Invocation Details</b> 8395** 8396** When an unlock-notify callback is registered, the application provides a 8397** single void* pointer that is passed to the callback when it is invoked. 8398** However, the signature of the callback function allows SQLite to pass 8399** it an array of void* context pointers. The first argument passed to 8400** an unlock-notify callback is a pointer to an array of void* pointers, 8401** and the second is the number of entries in the array. 8402** 8403** When a blocking connections transaction is concluded, there may be 8404** more than one blocked connection that has registered for an unlock-notify 8405** callback. ^If two or more such blocked connections have specified the 8406** same callback function, then instead of invoking the callback function 8407** multiple times, it is invoked once with the set of void* context pointers 8408** specified by the blocked connections bundled together into an array. 8409** This gives the application an opportunity to prioritize any actions 8410** related to the set of unblocked database connections. 8411** 8412** <b>Deadlock Detection</b> 8413** 8414** Assuming that after registering for an unlock-notify callback a 8415** database waits for the callback to be issued before taking any further 8416** action (a reasonable assumption), then using this API may cause the 8417** application to deadlock. For example, if connection X is waiting for 8418** connection Y's transaction to be concluded, and similarly connection 8419** Y is waiting on connection X's transaction, then neither connection 8420** will proceed and the system may remain deadlocked indefinitely. 8421** 8422** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 8423** detection. ^If a given call to sqlite3_unlock_notify() would put the 8424** system in a deadlocked state, then SQLITE_LOCKED is returned and no 8425** unlock-notify callback is registered. The system is said to be in 8426** a deadlocked state if connection A has registered for an unlock-notify 8427** callback on the conclusion of connection B's transaction, and connection 8428** B has itself registered for an unlock-notify callback when connection 8429** A's transaction is concluded. ^Indirect deadlock is also detected, so 8430** the system is also considered to be deadlocked if connection B has 8431** registered for an unlock-notify callback on the conclusion of connection 8432** C's transaction, where connection C is waiting on connection A. ^Any 8433** number of levels of indirection are allowed. 8434** 8435** <b>The "DROP TABLE" Exception</b> 8436** 8437** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 8438** always appropriate to call sqlite3_unlock_notify(). There is however, 8439** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 8440** SQLite checks if there are any currently executing SELECT statements 8441** that belong to the same connection. If there are, SQLITE_LOCKED is 8442** returned. In this case there is no "blocking connection", so invoking 8443** sqlite3_unlock_notify() results in the unlock-notify callback being 8444** invoked immediately. If the application then re-attempts the "DROP TABLE" 8445** or "DROP INDEX" query, an infinite loop might be the result. 8446** 8447** One way around this problem is to check the extended error code returned 8448** by an sqlite3_step() call. ^(If there is a blocking connection, then the 8449** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 8450** the special "DROP TABLE/INDEX" case, the extended error code is just 8451** SQLITE_LOCKED.)^ 8452*/ 8453int sqlite3_unlock_notify( 8454 sqlite3 *pBlocked, /* Waiting connection */ 8455 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 8456 void *pNotifyArg /* Argument to pass to xNotify */ 8457); 8458 8459 8460/* 8461** CAPI3REF: String Comparison 8462** 8463** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 8464** and extensions to compare the contents of two buffers containing UTF-8 8465** strings in a case-independent fashion, using the same definition of "case 8466** independence" that SQLite uses internally when comparing identifiers. 8467*/ 8468int sqlite3_stricmp(const char *, const char *); 8469int sqlite3_strnicmp(const char *, const char *, int); 8470 8471/* 8472** CAPI3REF: String Globbing 8473* 8474** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if 8475** string X matches the [GLOB] pattern P. 8476** ^The definition of [GLOB] pattern matching used in 8477** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the 8478** SQL dialect understood by SQLite. ^The [sqlite3_strglob(P,X)] function 8479** is case sensitive. 8480** 8481** Note that this routine returns zero on a match and non-zero if the strings 8482** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8483** 8484** See also: [sqlite3_strlike()]. 8485*/ 8486int sqlite3_strglob(const char *zGlob, const char *zStr); 8487 8488/* 8489** CAPI3REF: String LIKE Matching 8490* 8491** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if 8492** string X matches the [LIKE] pattern P with escape character E. 8493** ^The definition of [LIKE] pattern matching used in 8494** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E" 8495** operator in the SQL dialect understood by SQLite. ^For "X LIKE P" without 8496** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0. 8497** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case 8498** insensitive - equivalent upper and lower case ASCII characters match 8499** one another. 8500** 8501** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though 8502** only ASCII characters are case folded. 8503** 8504** Note that this routine returns zero on a match and non-zero if the strings 8505** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()]. 8506** 8507** See also: [sqlite3_strglob()]. 8508*/ 8509int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc); 8510 8511/* 8512** CAPI3REF: Error Logging Interface 8513** 8514** ^The [sqlite3_log()] interface writes a message into the [error log] 8515** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 8516** ^If logging is enabled, the zFormat string and subsequent arguments are 8517** used with [sqlite3_snprintf()] to generate the final output string. 8518** 8519** The sqlite3_log() interface is intended for use by extensions such as 8520** virtual tables, collating functions, and SQL functions. While there is 8521** nothing to prevent an application from calling sqlite3_log(), doing so 8522** is considered bad form. 8523** 8524** The zFormat string must not be NULL. 8525** 8526** To avoid deadlocks and other threading problems, the sqlite3_log() routine 8527** will not use dynamically allocated memory. The log message is stored in 8528** a fixed-length buffer on the stack. If the log message is longer than 8529** a few hundred characters, it will be truncated to the length of the 8530** buffer. 8531*/ 8532void sqlite3_log(int iErrCode, const char *zFormat, ...); 8533 8534/* 8535** CAPI3REF: Write-Ahead Log Commit Hook 8536** METHOD: sqlite3 8537** 8538** ^The [sqlite3_wal_hook()] function is used to register a callback that 8539** is invoked each time data is committed to a database in wal mode. 8540** 8541** ^(The callback is invoked by SQLite after the commit has taken place and 8542** the associated write-lock on the database released)^, so the implementation 8543** may read, write or [checkpoint] the database as required. 8544** 8545** ^The first parameter passed to the callback function when it is invoked 8546** is a copy of the third parameter passed to sqlite3_wal_hook() when 8547** registering the callback. ^The second is a copy of the database handle. 8548** ^The third parameter is the name of the database that was written to - 8549** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 8550** is the number of pages currently in the write-ahead log file, 8551** including those that were just committed. 8552** 8553** The callback function should normally return [SQLITE_OK]. ^If an error 8554** code is returned, that error will propagate back up through the 8555** SQLite code base to cause the statement that provoked the callback 8556** to report an error, though the commit will have still occurred. If the 8557** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 8558** that does not correspond to any valid SQLite error code, the results 8559** are undefined. 8560** 8561** A single database handle may have at most a single write-ahead log callback 8562** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 8563** previously registered write-ahead log callback. ^Note that the 8564** [sqlite3_wal_autocheckpoint()] interface and the 8565** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 8566** overwrite any prior [sqlite3_wal_hook()] settings. 8567*/ 8568void *sqlite3_wal_hook( 8569 sqlite3*, 8570 int(*)(void *,sqlite3*,const char*,int), 8571 void* 8572); 8573 8574/* 8575** CAPI3REF: Configure an auto-checkpoint 8576** METHOD: sqlite3 8577** 8578** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 8579** [sqlite3_wal_hook()] that causes any database on [database connection] D 8580** to automatically [checkpoint] 8581** after committing a transaction if there are N or 8582** more frames in the [write-ahead log] file. ^Passing zero or 8583** a negative value as the nFrame parameter disables automatic 8584** checkpoints entirely. 8585** 8586** ^The callback registered by this function replaces any existing callback 8587** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 8588** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 8589** configured by this function. 8590** 8591** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 8592** from SQL. 8593** 8594** ^Checkpoints initiated by this mechanism are 8595** [sqlite3_wal_checkpoint_v2|PASSIVE]. 8596** 8597** ^Every new [database connection] defaults to having the auto-checkpoint 8598** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 8599** pages. The use of this interface 8600** is only necessary if the default setting is found to be suboptimal 8601** for a particular application. 8602*/ 8603int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 8604 8605/* 8606** CAPI3REF: Checkpoint a database 8607** METHOD: sqlite3 8608** 8609** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to 8610** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^ 8611** 8612** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 8613** [write-ahead log] for database X on [database connection] D to be 8614** transferred into the database file and for the write-ahead log to 8615** be reset. See the [checkpointing] documentation for addition 8616** information. 8617** 8618** This interface used to be the only way to cause a checkpoint to 8619** occur. But then the newer and more powerful [sqlite3_wal_checkpoint_v2()] 8620** interface was added. This interface is retained for backwards 8621** compatibility and as a convenience for applications that need to manually 8622** start a callback but which do not need the full power (and corresponding 8623** complication) of [sqlite3_wal_checkpoint_v2()]. 8624*/ 8625int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 8626 8627/* 8628** CAPI3REF: Checkpoint a database 8629** METHOD: sqlite3 8630** 8631** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint 8632** operation on database X of [database connection] D in mode M. Status 8633** information is written back into integers pointed to by L and C.)^ 8634** ^(The M parameter must be a valid [checkpoint mode]:)^ 8635** 8636** <dl> 8637** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 8638** ^Checkpoint as many frames as possible without waiting for any database 8639** readers or writers to finish, then sync the database file if all frames 8640** in the log were checkpointed. ^The [busy-handler callback] 8641** is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode. 8642** ^On the other hand, passive mode might leave the checkpoint unfinished 8643** if there are concurrent readers or writers. 8644** 8645** <dt>SQLITE_CHECKPOINT_FULL<dd> 8646** ^This mode blocks (it invokes the 8647** [sqlite3_busy_handler|busy-handler callback]) until there is no 8648** database writer and all readers are reading from the most recent database 8649** snapshot. ^It then checkpoints all frames in the log file and syncs the 8650** database file. ^This mode blocks new database writers while it is pending, 8651** but new database readers are allowed to continue unimpeded. 8652** 8653** <dt>SQLITE_CHECKPOINT_RESTART<dd> 8654** ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition 8655** that after checkpointing the log file it blocks (calls the 8656** [busy-handler callback]) 8657** until all readers are reading from the database file only. ^This ensures 8658** that the next writer will restart the log file from the beginning. 8659** ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new 8660** database writer attempts while it is pending, but does not impede readers. 8661** 8662** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd> 8663** ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the 8664** addition that it also truncates the log file to zero bytes just prior 8665** to a successful return. 8666** </dl> 8667** 8668** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in 8669** the log file or to -1 if the checkpoint could not run because 8670** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not 8671** NULL,then *pnCkpt is set to the total number of checkpointed frames in the 8672** log file (including any that were already checkpointed before the function 8673** was called) or to -1 if the checkpoint could not run due to an error or 8674** because the database is not in WAL mode. ^Note that upon successful 8675** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been 8676** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero. 8677** 8678** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If 8679** any other process is running a checkpoint operation at the same time, the 8680** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 8681** busy-handler configured, it will not be invoked in this case. 8682** 8683** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 8684** exclusive "writer" lock on the database file. ^If the writer lock cannot be 8685** obtained immediately, and a busy-handler is configured, it is invoked and 8686** the writer lock retried until either the busy-handler returns 0 or the lock 8687** is successfully obtained. ^The busy-handler is also invoked while waiting for 8688** database readers as described above. ^If the busy-handler returns 0 before 8689** the writer lock is obtained or while waiting for database readers, the 8690** checkpoint operation proceeds from that point in the same way as 8691** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 8692** without blocking any further. ^SQLITE_BUSY is returned in this case. 8693** 8694** ^If parameter zDb is NULL or points to a zero length string, then the 8695** specified operation is attempted on all WAL databases [attached] to 8696** [database connection] db. In this case the 8697** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 8698** an SQLITE_BUSY error is encountered when processing one or more of the 8699** attached WAL databases, the operation is still attempted on any remaining 8700** attached databases and SQLITE_BUSY is returned at the end. ^If any other 8701** error occurs while processing an attached database, processing is abandoned 8702** and the error code is returned to the caller immediately. ^If no error 8703** (SQLITE_BUSY or otherwise) is encountered while processing the attached 8704** databases, SQLITE_OK is returned. 8705** 8706** ^If database zDb is the name of an attached database that is not in WAL 8707** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If 8708** zDb is not NULL (or a zero length string) and is not the name of any 8709** attached database, SQLITE_ERROR is returned to the caller. 8710** 8711** ^Unless it returns SQLITE_MISUSE, 8712** the sqlite3_wal_checkpoint_v2() interface 8713** sets the error information that is queried by 8714** [sqlite3_errcode()] and [sqlite3_errmsg()]. 8715** 8716** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface 8717** from SQL. 8718*/ 8719int sqlite3_wal_checkpoint_v2( 8720 sqlite3 *db, /* Database handle */ 8721 const char *zDb, /* Name of attached database (or NULL) */ 8722 int eMode, /* SQLITE_CHECKPOINT_* value */ 8723 int *pnLog, /* OUT: Size of WAL log in frames */ 8724 int *pnCkpt /* OUT: Total number of frames checkpointed */ 8725); 8726 8727/* 8728** CAPI3REF: Checkpoint Mode Values 8729** KEYWORDS: {checkpoint mode} 8730** 8731** These constants define all valid values for the "checkpoint mode" passed 8732** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface. 8733** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the 8734** meaning of each of these checkpoint modes. 8735*/ 8736#define SQLITE_CHECKPOINT_PASSIVE 0 /* Do as much as possible w/o blocking */ 8737#define SQLITE_CHECKPOINT_FULL 1 /* Wait for writers, then checkpoint */ 8738#define SQLITE_CHECKPOINT_RESTART 2 /* Like FULL but wait for for readers */ 8739#define SQLITE_CHECKPOINT_TRUNCATE 3 /* Like RESTART but also truncate WAL */ 8740 8741/* 8742** CAPI3REF: Virtual Table Interface Configuration 8743** 8744** This function may be called by either the [xConnect] or [xCreate] method 8745** of a [virtual table] implementation to configure 8746** various facets of the virtual table interface. 8747** 8748** If this interface is invoked outside the context of an xConnect or 8749** xCreate virtual table method then the behavior is undefined. 8750** 8751** At present, there is only one option that may be configured using 8752** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 8753** may be added in the future. 8754*/ 8755int sqlite3_vtab_config(sqlite3*, int op, ...); 8756 8757/* 8758** CAPI3REF: Virtual Table Configuration Options 8759** 8760** These macros define the various options to the 8761** [sqlite3_vtab_config()] interface that [virtual table] implementations 8762** can use to customize and optimize their behavior. 8763** 8764** <dl> 8765** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]] 8766** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 8767** <dd>Calls of the form 8768** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 8769** where X is an integer. If X is zero, then the [virtual table] whose 8770** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 8771** support constraints. In this configuration (which is the default) if 8772** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 8773** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 8774** specified as part of the users SQL statement, regardless of the actual 8775** ON CONFLICT mode specified. 8776** 8777** If X is non-zero, then the virtual table implementation guarantees 8778** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 8779** any modifications to internal or persistent data structures have been made. 8780** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 8781** is able to roll back a statement or database transaction, and abandon 8782** or continue processing the current SQL statement as appropriate. 8783** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 8784** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 8785** had been ABORT. 8786** 8787** Virtual table implementations that are required to handle OR REPLACE 8788** must do so within the [xUpdate] method. If a call to the 8789** [sqlite3_vtab_on_conflict()] function indicates that the current ON 8790** CONFLICT policy is REPLACE, the virtual table implementation should 8791** silently replace the appropriate rows within the xUpdate callback and 8792** return SQLITE_OK. Or, if this is not possible, it may return 8793** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 8794** constraint handling. 8795** </dl> 8796*/ 8797#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 8798 8799/* 8800** CAPI3REF: Determine The Virtual Table Conflict Policy 8801** 8802** This function may only be called from within a call to the [xUpdate] method 8803** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 8804** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 8805** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 8806** of the SQL statement that triggered the call to the [xUpdate] method of the 8807** [virtual table]. 8808*/ 8809int sqlite3_vtab_on_conflict(sqlite3 *); 8810 8811/* 8812** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE 8813** 8814** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn] 8815** method of a [virtual table], then it returns true if and only if the 8816** column is being fetched as part of an UPDATE operation during which the 8817** column value will not change. Applications might use this to substitute 8818** a return value that is less expensive to compute and that the corresponding 8819** [xUpdate] method understands as a "no-change" value. 8820** 8821** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that 8822** the column is not changed by the UPDATE statement, then the xColumn 8823** method can optionally return without setting a result, without calling 8824** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces]. 8825** In that case, [sqlite3_value_nochange(X)] will return true for the 8826** same column in the [xUpdate] method. 8827*/ 8828int sqlite3_vtab_nochange(sqlite3_context*); 8829 8830/* 8831** CAPI3REF: Determine The Collation For a Virtual Table Constraint 8832** 8833** This function may only be called from within a call to the [xBestIndex] 8834** method of a [virtual table]. 8835** 8836** The first argument must be the sqlite3_index_info object that is the 8837** first parameter to the xBestIndex() method. The second argument must be 8838** an index into the aConstraint[] array belonging to the sqlite3_index_info 8839** structure passed to xBestIndex. This function returns a pointer to a buffer 8840** containing the name of the collation sequence for the corresponding 8841** constraint. 8842*/ 8843SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int); 8844 8845/* 8846** CAPI3REF: Conflict resolution modes 8847** KEYWORDS: {conflict resolution mode} 8848** 8849** These constants are returned by [sqlite3_vtab_on_conflict()] to 8850** inform a [virtual table] implementation what the [ON CONFLICT] mode 8851** is for the SQL statement being evaluated. 8852** 8853** Note that the [SQLITE_IGNORE] constant is also used as a potential 8854** return value from the [sqlite3_set_authorizer()] callback and that 8855** [SQLITE_ABORT] is also a [result code]. 8856*/ 8857#define SQLITE_ROLLBACK 1 8858/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 8859#define SQLITE_FAIL 3 8860/* #define SQLITE_ABORT 4 // Also an error code */ 8861#define SQLITE_REPLACE 5 8862 8863/* 8864** CAPI3REF: Prepared Statement Scan Status Opcodes 8865** KEYWORDS: {scanstatus options} 8866** 8867** The following constants can be used for the T parameter to the 8868** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a 8869** different metric for sqlite3_stmt_scanstatus() to return. 8870** 8871** When the value returned to V is a string, space to hold that string is 8872** managed by the prepared statement S and will be automatically freed when 8873** S is finalized. 8874** 8875** <dl> 8876** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt> 8877** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be 8878** set to the total number of times that the X-th loop has run.</dd> 8879** 8880** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt> 8881** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set 8882** to the total number of rows examined by all iterations of the X-th loop.</dd> 8883** 8884** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt> 8885** <dd>^The "double" variable pointed to by the T parameter will be set to the 8886** query planner's estimate for the average number of rows output from each 8887** iteration of the X-th loop. If the query planner's estimates was accurate, 8888** then this value will approximate the quotient NVISIT/NLOOP and the 8889** product of this value for all prior loops with the same SELECTID will 8890** be the NLOOP value for the current loop. 8891** 8892** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt> 8893** <dd>^The "const char *" variable pointed to by the T parameter will be set 8894** to a zero-terminated UTF-8 string containing the name of the index or table 8895** used for the X-th loop. 8896** 8897** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt> 8898** <dd>^The "const char *" variable pointed to by the T parameter will be set 8899** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN] 8900** description for the X-th loop. 8901** 8902** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt> 8903** <dd>^The "int" variable pointed to by the T parameter will be set to the 8904** "select-id" for the X-th loop. The select-id identifies which query or 8905** subquery the loop is part of. The main query has a select-id of zero. 8906** The select-id is the same value as is output in the first column 8907** of an [EXPLAIN QUERY PLAN] query. 8908** </dl> 8909*/ 8910#define SQLITE_SCANSTAT_NLOOP 0 8911#define SQLITE_SCANSTAT_NVISIT 1 8912#define SQLITE_SCANSTAT_EST 2 8913#define SQLITE_SCANSTAT_NAME 3 8914#define SQLITE_SCANSTAT_EXPLAIN 4 8915#define SQLITE_SCANSTAT_SELECTID 5 8916 8917/* 8918** CAPI3REF: Prepared Statement Scan Status 8919** METHOD: sqlite3_stmt 8920** 8921** This interface returns information about the predicted and measured 8922** performance for pStmt. Advanced applications can use this 8923** interface to compare the predicted and the measured performance and 8924** issue warnings and/or rerun [ANALYZE] if discrepancies are found. 8925** 8926** Since this interface is expected to be rarely used, it is only 8927** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS] 8928** compile-time option. 8929** 8930** The "iScanStatusOp" parameter determines which status information to return. 8931** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior 8932** of this interface is undefined. 8933** ^The requested measurement is written into a variable pointed to by 8934** the "pOut" parameter. 8935** Parameter "idx" identifies the specific loop to retrieve statistics for. 8936** Loops are numbered starting from zero. ^If idx is out of range - less than 8937** zero or greater than or equal to the total number of loops used to implement 8938** the statement - a non-zero value is returned and the variable that pOut 8939** points to is unchanged. 8940** 8941** ^Statistics might not be available for all loops in all statements. ^In cases 8942** where there exist loops with no available statistics, this function behaves 8943** as if the loop did not exist - it returns non-zero and leave the variable 8944** that pOut points to unchanged. 8945** 8946** See also: [sqlite3_stmt_scanstatus_reset()] 8947*/ 8948int sqlite3_stmt_scanstatus( 8949 sqlite3_stmt *pStmt, /* Prepared statement for which info desired */ 8950 int idx, /* Index of loop to report on */ 8951 int iScanStatusOp, /* Information desired. SQLITE_SCANSTAT_* */ 8952 void *pOut /* Result written here */ 8953); 8954 8955/* 8956** CAPI3REF: Zero Scan-Status Counters 8957** METHOD: sqlite3_stmt 8958** 8959** ^Zero all [sqlite3_stmt_scanstatus()] related event counters. 8960** 8961** This API is only available if the library is built with pre-processor 8962** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined. 8963*/ 8964void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*); 8965 8966/* 8967** CAPI3REF: Flush caches to disk mid-transaction 8968** 8969** ^If a write-transaction is open on [database connection] D when the 8970** [sqlite3_db_cacheflush(D)] interface invoked, any dirty 8971** pages in the pager-cache that are not currently in use are written out 8972** to disk. A dirty page may be in use if a database cursor created by an 8973** active SQL statement is reading from it, or if it is page 1 of a database 8974** file (page 1 is always "in use"). ^The [sqlite3_db_cacheflush(D)] 8975** interface flushes caches for all schemas - "main", "temp", and 8976** any [attached] databases. 8977** 8978** ^If this function needs to obtain extra database locks before dirty pages 8979** can be flushed to disk, it does so. ^If those locks cannot be obtained 8980** immediately and there is a busy-handler callback configured, it is invoked 8981** in the usual manner. ^If the required lock still cannot be obtained, then 8982** the database is skipped and an attempt made to flush any dirty pages 8983** belonging to the next (if any) database. ^If any databases are skipped 8984** because locks cannot be obtained, but no other error occurs, this 8985** function returns SQLITE_BUSY. 8986** 8987** ^If any other error occurs while flushing dirty pages to disk (for 8988** example an IO error or out-of-memory condition), then processing is 8989** abandoned and an SQLite [error code] is returned to the caller immediately. 8990** 8991** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK. 8992** 8993** ^This function does not set the database handle error code or message 8994** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions. 8995*/ 8996int sqlite3_db_cacheflush(sqlite3*); 8997 8998/* 8999** CAPI3REF: The pre-update hook. 9000** 9001** ^These interfaces are only available if SQLite is compiled using the 9002** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option. 9003** 9004** ^The [sqlite3_preupdate_hook()] interface registers a callback function 9005** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation 9006** on a database table. 9007** ^At most one preupdate hook may be registered at a time on a single 9008** [database connection]; each call to [sqlite3_preupdate_hook()] overrides 9009** the previous setting. 9010** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()] 9011** with a NULL pointer as the second parameter. 9012** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as 9013** the first parameter to callbacks. 9014** 9015** ^The preupdate hook only fires for changes to real database tables; the 9016** preupdate hook is not invoked for changes to [virtual tables] or to 9017** system tables like sqlite_master or sqlite_stat1. 9018** 9019** ^The second parameter to the preupdate callback is a pointer to 9020** the [database connection] that registered the preupdate hook. 9021** ^The third parameter to the preupdate callback is one of the constants 9022** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the 9023** kind of update operation that is about to occur. 9024** ^(The fourth parameter to the preupdate callback is the name of the 9025** database within the database connection that is being modified. This 9026** will be "main" for the main database or "temp" for TEMP tables or 9027** the name given after the AS keyword in the [ATTACH] statement for attached 9028** databases.)^ 9029** ^The fifth parameter to the preupdate callback is the name of the 9030** table that is being modified. 9031** 9032** For an UPDATE or DELETE operation on a [rowid table], the sixth 9033** parameter passed to the preupdate callback is the initial [rowid] of the 9034** row being modified or deleted. For an INSERT operation on a rowid table, 9035** or any operation on a WITHOUT ROWID table, the value of the sixth 9036** parameter is undefined. For an INSERT or UPDATE on a rowid table the 9037** seventh parameter is the final rowid value of the row being inserted 9038** or updated. The value of the seventh parameter passed to the callback 9039** function is not defined for operations on WITHOUT ROWID tables, or for 9040** INSERT operations on rowid tables. 9041** 9042** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()], 9043** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces 9044** provide additional information about a preupdate event. These routines 9045** may only be called from within a preupdate callback. Invoking any of 9046** these routines from outside of a preupdate callback or with a 9047** [database connection] pointer that is different from the one supplied 9048** to the preupdate callback results in undefined and probably undesirable 9049** behavior. 9050** 9051** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns 9052** in the row that is being inserted, updated, or deleted. 9053** 9054** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to 9055** a [protected sqlite3_value] that contains the value of the Nth column of 9056** the table row before it is updated. The N parameter must be between 0 9057** and one less than the number of columns or the behavior will be 9058** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE 9059** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the 9060** behavior is undefined. The [sqlite3_value] that P points to 9061** will be destroyed when the preupdate callback returns. 9062** 9063** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to 9064** a [protected sqlite3_value] that contains the value of the Nth column of 9065** the table row after it is updated. The N parameter must be between 0 9066** and one less than the number of columns or the behavior will be 9067** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE 9068** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the 9069** behavior is undefined. The [sqlite3_value] that P points to 9070** will be destroyed when the preupdate callback returns. 9071** 9072** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate 9073** callback was invoked as a result of a direct insert, update, or delete 9074** operation; or 1 for inserts, updates, or deletes invoked by top-level 9075** triggers; or 2 for changes resulting from triggers called by top-level 9076** triggers; and so forth. 9077** 9078** See also: [sqlite3_update_hook()] 9079*/ 9080#if defined(SQLITE_ENABLE_PREUPDATE_HOOK) 9081void *sqlite3_preupdate_hook( 9082 sqlite3 *db, 9083 void(*xPreUpdate)( 9084 void *pCtx, /* Copy of third arg to preupdate_hook() */ 9085 sqlite3 *db, /* Database handle */ 9086 int op, /* SQLITE_UPDATE, DELETE or INSERT */ 9087 char const *zDb, /* Database name */ 9088 char const *zName, /* Table name */ 9089 sqlite3_int64 iKey1, /* Rowid of row about to be deleted/updated */ 9090 sqlite3_int64 iKey2 /* New rowid value (for a rowid UPDATE) */ 9091 ), 9092 void* 9093); 9094int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **); 9095int sqlite3_preupdate_count(sqlite3 *); 9096int sqlite3_preupdate_depth(sqlite3 *); 9097int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **); 9098#endif 9099 9100/* 9101** CAPI3REF: Low-level system error code 9102** 9103** ^Attempt to return the underlying operating system error code or error 9104** number that caused the most recent I/O error or failure to open a file. 9105** The return value is OS-dependent. For example, on unix systems, after 9106** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be 9107** called to get back the underlying "errno" that caused the problem, such 9108** as ENOSPC, EAUTH, EISDIR, and so forth. 9109*/ 9110int sqlite3_system_errno(sqlite3*); 9111 9112/* 9113** CAPI3REF: Database Snapshot 9114** KEYWORDS: {snapshot} {sqlite3_snapshot} 9115** 9116** An instance of the snapshot object records the state of a [WAL mode] 9117** database for some specific point in history. 9118** 9119** In [WAL mode], multiple [database connections] that are open on the 9120** same database file can each be reading a different historical version 9121** of the database file. When a [database connection] begins a read 9122** transaction, that connection sees an unchanging copy of the database 9123** as it existed for the point in time when the transaction first started. 9124** Subsequent changes to the database from other connections are not seen 9125** by the reader until a new read transaction is started. 9126** 9127** The sqlite3_snapshot object records state information about an historical 9128** version of the database file so that it is possible to later open a new read 9129** transaction that sees that historical version of the database rather than 9130** the most recent version. 9131*/ 9132typedef struct sqlite3_snapshot { 9133 unsigned char hidden[48]; 9134} sqlite3_snapshot; 9135 9136/* 9137** CAPI3REF: Record A Database Snapshot 9138** CONSTRUCTOR: sqlite3_snapshot 9139** 9140** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a 9141** new [sqlite3_snapshot] object that records the current state of 9142** schema S in database connection D. ^On success, the 9143** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly 9144** created [sqlite3_snapshot] object into *P and returns SQLITE_OK. 9145** If there is not already a read-transaction open on schema S when 9146** this function is called, one is opened automatically. 9147** 9148** The following must be true for this function to succeed. If any of 9149** the following statements are false when sqlite3_snapshot_get() is 9150** called, SQLITE_ERROR is returned. The final value of *P is undefined 9151** in this case. 9152** 9153** <ul> 9154** <li> The database handle must not be in [autocommit mode]. 9155** 9156** <li> Schema S of [database connection] D must be a [WAL mode] database. 9157** 9158** <li> There must not be a write transaction open on schema S of database 9159** connection D. 9160** 9161** <li> One or more transactions must have been written to the current wal 9162** file since it was created on disk (by any connection). This means 9163** that a snapshot cannot be taken on a wal mode database with no wal 9164** file immediately after it is first opened. At least one transaction 9165** must be written to it first. 9166** </ul> 9167** 9168** This function may also return SQLITE_NOMEM. If it is called with the 9169** database handle in autocommit mode but fails for some other reason, 9170** whether or not a read transaction is opened on schema S is undefined. 9171** 9172** The [sqlite3_snapshot] object returned from a successful call to 9173** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()] 9174** to avoid a memory leak. 9175** 9176** The [sqlite3_snapshot_get()] interface is only available when the 9177** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9178*/ 9179SQLITE_EXPERIMENTAL int sqlite3_snapshot_get( 9180 sqlite3 *db, 9181 const char *zSchema, 9182 sqlite3_snapshot **ppSnapshot 9183); 9184 9185/* 9186** CAPI3REF: Start a read transaction on an historical snapshot 9187** METHOD: sqlite3_snapshot 9188** 9189** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read 9190** transaction or upgrades an existing one for schema S of 9191** [database connection] D such that the read transaction refers to 9192** historical [snapshot] P, rather than the most recent change to the 9193** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK 9194** on success or an appropriate [error code] if it fails. 9195** 9196** ^In order to succeed, the database connection must not be in 9197** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there 9198** is already a read transaction open on schema S, then the database handle 9199** must have no active statements (SELECT statements that have been passed 9200** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()). 9201** SQLITE_ERROR is returned if either of these conditions is violated, or 9202** if schema S does not exist, or if the snapshot object is invalid. 9203** 9204** ^A call to sqlite3_snapshot_open() will fail to open if the specified 9205** snapshot has been overwritten by a [checkpoint]. In this case 9206** SQLITE_ERROR_SNAPSHOT is returned. 9207** 9208** If there is already a read transaction open when this function is 9209** invoked, then the same read transaction remains open (on the same 9210** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT 9211** is returned. If another error code - for example SQLITE_PROTOCOL or an 9212** SQLITE_IOERR error code - is returned, then the final state of the 9213** read transaction is undefined. If SQLITE_OK is returned, then the 9214** read transaction is now open on database snapshot P. 9215** 9216** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the 9217** database connection D does not know that the database file for 9218** schema S is in [WAL mode]. A database connection might not know 9219** that the database file is in [WAL mode] if there has been no prior 9220** I/O on that database connection, or if the database entered [WAL mode] 9221** after the most recent I/O on the database connection.)^ 9222** (Hint: Run "[PRAGMA application_id]" against a newly opened 9223** database connection in order to make it ready to use snapshots.) 9224** 9225** The [sqlite3_snapshot_open()] interface is only available when the 9226** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9227*/ 9228SQLITE_EXPERIMENTAL int sqlite3_snapshot_open( 9229 sqlite3 *db, 9230 const char *zSchema, 9231 sqlite3_snapshot *pSnapshot 9232); 9233 9234/* 9235** CAPI3REF: Destroy a snapshot 9236** DESTRUCTOR: sqlite3_snapshot 9237** 9238** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P. 9239** The application must eventually free every [sqlite3_snapshot] object 9240** using this routine to avoid a memory leak. 9241** 9242** The [sqlite3_snapshot_free()] interface is only available when the 9243** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used. 9244*/ 9245SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*); 9246 9247/* 9248** CAPI3REF: Compare the ages of two snapshot handles. 9249** METHOD: sqlite3_snapshot 9250** 9251** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages 9252** of two valid snapshot handles. 9253** 9254** If the two snapshot handles are not associated with the same database 9255** file, the result of the comparison is undefined. 9256** 9257** Additionally, the result of the comparison is only valid if both of the 9258** snapshot handles were obtained by calling sqlite3_snapshot_get() since the 9259** last time the wal file was deleted. The wal file is deleted when the 9260** database is changed back to rollback mode or when the number of database 9261** clients drops to zero. If either snapshot handle was obtained before the 9262** wal file was last deleted, the value returned by this function 9263** is undefined. 9264** 9265** Otherwise, this API returns a negative value if P1 refers to an older 9266** snapshot than P2, zero if the two handles refer to the same database 9267** snapshot, and a positive value if P1 is a newer snapshot than P2. 9268** 9269** This interface is only available if SQLite is compiled with the 9270** [SQLITE_ENABLE_SNAPSHOT] option. 9271*/ 9272SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp( 9273 sqlite3_snapshot *p1, 9274 sqlite3_snapshot *p2 9275); 9276 9277/* 9278** CAPI3REF: Recover snapshots from a wal file 9279** METHOD: sqlite3_snapshot 9280** 9281** If a [WAL file] remains on disk after all database connections close 9282** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control] 9283** or because the last process to have the database opened exited without 9284** calling [sqlite3_close()]) and a new connection is subsequently opened 9285** on that database and [WAL file], the [sqlite3_snapshot_open()] interface 9286** will only be able to open the last transaction added to the WAL file 9287** even though the WAL file contains other valid transactions. 9288** 9289** This function attempts to scan the WAL file associated with database zDb 9290** of database handle db and make all valid snapshots available to 9291** sqlite3_snapshot_open(). It is an error if there is already a read 9292** transaction open on the database, or if the database is not a WAL mode 9293** database. 9294** 9295** SQLITE_OK is returned if successful, or an SQLite error code otherwise. 9296** 9297** This interface is only available if SQLite is compiled with the 9298** [SQLITE_ENABLE_SNAPSHOT] option. 9299*/ 9300SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb); 9301 9302/* 9303** CAPI3REF: Serialize a database 9304** 9305** The sqlite3_serialize(D,S,P,F) interface returns a pointer to memory 9306** that is a serialization of the S database on [database connection] D. 9307** If P is not a NULL pointer, then the size of the database in bytes 9308** is written into *P. 9309** 9310** For an ordinary on-disk database file, the serialization is just a 9311** copy of the disk file. For an in-memory database or a "TEMP" database, 9312** the serialization is the same sequence of bytes which would be written 9313** to disk if that database where backed up to disk. 9314** 9315** The usual case is that sqlite3_serialize() copies the serialization of 9316** the database into memory obtained from [sqlite3_malloc64()] and returns 9317** a pointer to that memory. The caller is responsible for freeing the 9318** returned value to avoid a memory leak. However, if the F argument 9319** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations 9320** are made, and the sqlite3_serialize() function will return a pointer 9321** to the contiguous memory representation of the database that SQLite 9322** is currently using for that database, or NULL if the no such contiguous 9323** memory representation of the database exists. A contiguous memory 9324** representation of the database will usually only exist if there has 9325** been a prior call to [sqlite3_deserialize(D,S,...)] with the same 9326** values of D and S. 9327** The size of the database is written into *P even if the 9328** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy 9329** of the database exists. 9330** 9331** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the 9332** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory 9333** allocation error occurs. 9334** 9335** This interface is only available if SQLite is compiled with the 9336** [SQLITE_ENABLE_DESERIALIZE] option. 9337*/ 9338unsigned char *sqlite3_serialize( 9339 sqlite3 *db, /* The database connection */ 9340 const char *zSchema, /* Which DB to serialize. ex: "main", "temp", ... */ 9341 sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */ 9342 unsigned int mFlags /* Zero or more SQLITE_SERIALIZE_* flags */ 9343); 9344 9345/* 9346** CAPI3REF: Flags for sqlite3_serialize 9347** 9348** Zero or more of the following constants can be OR-ed together for 9349** the F argument to [sqlite3_serialize(D,S,P,F)]. 9350** 9351** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return 9352** a pointer to contiguous in-memory database that it is currently using, 9353** without making a copy of the database. If SQLite is not currently using 9354** a contiguous in-memory database, then this option causes 9355** [sqlite3_serialize()] to return a NULL pointer. SQLite will only be 9356** using a contiguous in-memory database if it has been initialized by a 9357** prior call to [sqlite3_deserialize()]. 9358*/ 9359#define SQLITE_SERIALIZE_NOCOPY 0x001 /* Do no memory allocations */ 9360 9361/* 9362** CAPI3REF: Deserialize a database 9363** 9364** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the 9365** [database connection] D to disconnect from database S and then 9366** reopen S as an in-memory database based on the serialization contained 9367** in P. The serialized database P is N bytes in size. M is the size of 9368** the buffer P, which might be larger than N. If M is larger than N, and 9369** the SQLITE_DESERIALIZE_READONLY bit is not set in F, then SQLite is 9370** permitted to add content to the in-memory database as long as the total 9371** size does not exceed M bytes. 9372** 9373** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will 9374** invoke sqlite3_free() on the serialization buffer when the database 9375** connection closes. If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then 9376** SQLite will try to increase the buffer size using sqlite3_realloc64() 9377** if writes on the database cause it to grow larger than M bytes. 9378** 9379** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the 9380** database is currently in a read transaction or is involved in a backup 9381** operation. 9382** 9383** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the 9384** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then 9385** [sqlite3_free()] is invoked on argument P prior to returning. 9386** 9387** This interface is only available if SQLite is compiled with the 9388** [SQLITE_ENABLE_DESERIALIZE] option. 9389*/ 9390int sqlite3_deserialize( 9391 sqlite3 *db, /* The database connection */ 9392 const char *zSchema, /* Which DB to reopen with the deserialization */ 9393 unsigned char *pData, /* The serialized database content */ 9394 sqlite3_int64 szDb, /* Number bytes in the deserialization */ 9395 sqlite3_int64 szBuf, /* Total size of buffer pData[] */ 9396 unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ 9397); 9398 9399/* 9400** CAPI3REF: Flags for sqlite3_deserialize() 9401** 9402** The following are allowed values for 6th argument (the F argument) to 9403** the [sqlite3_deserialize(D,S,P,N,M,F)] interface. 9404** 9405** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization 9406** in the P argument is held in memory obtained from [sqlite3_malloc64()] 9407** and that SQLite should take ownership of this memory and automatically 9408** free it when it has finished using it. Without this flag, the caller 9409** is responsible for freeing any dynamically allocated memory. 9410** 9411** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to 9412** grow the size of the database using calls to [sqlite3_realloc64()]. This 9413** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used. 9414** Without this flag, the deserialized database cannot increase in size beyond 9415** the number of bytes specified by the M parameter. 9416** 9417** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database 9418** should be treated as read-only. 9419*/ 9420#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */ 9421#define SQLITE_DESERIALIZE_RESIZEABLE 2 /* Resize using sqlite3_realloc64() */ 9422#define SQLITE_DESERIALIZE_READONLY 4 /* Database is read-only */ 9423 9424/* 9425** Undo the hack that converts floating point types to integer for 9426** builds on processors without floating point support. 9427*/ 9428#ifdef SQLITE_OMIT_FLOATING_POINT 9429# undef double 9430#endif 9431 9432#ifdef __cplusplus 9433} /* End of the 'extern "C"' block */ 9434#endif 9435#endif /* SQLITE3_H */ 9436