1/* 2** 2001 September 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 suppose 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** Add the ability to override 'extern' 47*/ 48#ifndef SQLITE_EXTERN 49# define SQLITE_EXTERN extern 50#endif 51 52#ifndef SQLITE_API 53# define SQLITE_API 54#endif 55 56 57/* 58** These no-op macros are used in front of interfaces to mark those 59** interfaces as either deprecated or experimental. New applications 60** should not use deprecated interfaces - they are support for backwards 61** compatibility only. Application writers should be aware that 62** experimental interfaces are subject to change in point releases. 63** 64** These macros used to resolve to various kinds of compiler magic that 65** would generate warning messages when they were used. But that 66** compiler magic ended up generating such a flurry of bug reports 67** that we have taken it all out and gone back to using simple 68** noop macros. 69*/ 70#define SQLITE_DEPRECATED 71#define SQLITE_EXPERIMENTAL 72 73/* 74** Ensure these symbols were not defined by some previous header file. 75*/ 76#ifdef SQLITE_VERSION 77# undef SQLITE_VERSION 78#endif 79#ifdef SQLITE_VERSION_NUMBER 80# undef SQLITE_VERSION_NUMBER 81#endif 82 83/* 84** CAPI3REF: Compile-Time Library Version Numbers 85** 86** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 87** evaluates to a string literal that is the SQLite version in the 88** format "X.Y.Z" where X is the major version number (always 3 for 89** SQLite3) and Y is the minor version number and Z is the release number.)^ 90** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 91** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 92** numbers used in [SQLITE_VERSION].)^ 93** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 94** be larger than the release from which it is derived. Either Y will 95** be held constant and Z will be incremented or else Y will be incremented 96** and Z will be reset to zero. 97** 98** Since version 3.6.18, SQLite source code has been stored in the 99** <a href="http://www.fossil-scm.org/">Fossil configuration management 100** system</a>. ^The SQLITE_SOURCE_ID macro evaluates to 101** a string which identifies a particular check-in of SQLite 102** within its configuration management system. ^The SQLITE_SOURCE_ID 103** string contains the date and time of the check-in (UTC) and an SHA1 104** hash of the entire source tree. 105** 106** See also: [sqlite3_libversion()], 107** [sqlite3_libversion_number()], [sqlite3_sourceid()], 108** [sqlite_version()] and [sqlite_source_id()]. 109*/ 110#define SQLITE_VERSION "3.7.11" 111#define SQLITE_VERSION_NUMBER 3007011 112#define SQLITE_SOURCE_ID "2012-03-20 11:35:50 00bb9c9ce4f465e6ac321ced2a9d0062dc364669" 113 114/* 115** CAPI3REF: Run-Time Library Version Numbers 116** KEYWORDS: sqlite3_version, sqlite3_sourceid 117** 118** These interfaces provide the same information as the [SQLITE_VERSION], 119** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 120** but are associated with the library instead of the header file. ^(Cautious 121** programmers might include assert() statements in their application to 122** verify that values returned by these interfaces match the macros in 123** the header, and thus insure that the application is 124** compiled with matching library and header files. 125** 126** <blockquote><pre> 127** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 128** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 129** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 130** </pre></blockquote>)^ 131** 132** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 133** macro. ^The sqlite3_libversion() function returns a pointer to the 134** to the sqlite3_version[] string constant. The sqlite3_libversion() 135** function is provided for use in DLLs since DLL users usually do not have 136** direct access to string constants within the DLL. ^The 137** sqlite3_libversion_number() function returns an integer equal to 138** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function returns 139** a pointer to a string constant whose value is the same as the 140** [SQLITE_SOURCE_ID] C preprocessor macro. 141** 142** See also: [sqlite_version()] and [sqlite_source_id()]. 143*/ 144SQLITE_API SQLITE_EXTERN const char sqlite3_version[]; 145SQLITE_API const char *sqlite3_libversion(void); 146SQLITE_API const char *sqlite3_sourceid(void); 147SQLITE_API int sqlite3_libversion_number(void); 148 149/* 150** CAPI3REF: Run-Time Library Compilation Options Diagnostics 151** 152** ^The sqlite3_compileoption_used() function returns 0 or 1 153** indicating whether the specified option was defined at 154** compile time. ^The SQLITE_ prefix may be omitted from the 155** option name passed to sqlite3_compileoption_used(). 156** 157** ^The sqlite3_compileoption_get() function allows iterating 158** over the list of options that were defined at compile time by 159** returning the N-th compile time option string. ^If N is out of range, 160** sqlite3_compileoption_get() returns a NULL pointer. ^The SQLITE_ 161** prefix is omitted from any strings returned by 162** sqlite3_compileoption_get(). 163** 164** ^Support for the diagnostic functions sqlite3_compileoption_used() 165** and sqlite3_compileoption_get() may be omitted by specifying the 166** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time. 167** 168** See also: SQL functions [sqlite_compileoption_used()] and 169** [sqlite_compileoption_get()] and the [compile_options pragma]. 170*/ 171#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS 172SQLITE_API int sqlite3_compileoption_used(const char *zOptName); 173SQLITE_API const char *sqlite3_compileoption_get(int N); 174#endif 175 176/* 177** CAPI3REF: Test To See If The Library Is Threadsafe 178** 179** ^The sqlite3_threadsafe() function returns zero if and only if 180** SQLite was compiled with mutexing code omitted due to the 181** [SQLITE_THREADSAFE] compile-time option being set to 0. 182** 183** SQLite can be compiled with or without mutexes. When 184** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 185** are enabled and SQLite is threadsafe. When the 186** [SQLITE_THREADSAFE] macro is 0, 187** the mutexes are omitted. Without the mutexes, it is not safe 188** to use SQLite concurrently from more than one thread. 189** 190** Enabling mutexes incurs a measurable performance penalty. 191** So if speed is of utmost importance, it makes sense to disable 192** the mutexes. But for maximum safety, mutexes should be enabled. 193** ^The default behavior is for mutexes to be enabled. 194** 195** This interface can be used by an application to make sure that the 196** version of SQLite that it is linking against was compiled with 197** the desired setting of the [SQLITE_THREADSAFE] macro. 198** 199** This interface only reports on the compile-time mutex setting 200** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 201** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 202** can be fully or partially disabled using a call to [sqlite3_config()] 203** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 204** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 205** sqlite3_threadsafe() function shows only the compile-time setting of 206** thread safety, not any run-time changes to that setting made by 207** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 208** is unchanged by calls to sqlite3_config().)^ 209** 210** See the [threading mode] documentation for additional information. 211*/ 212SQLITE_API int sqlite3_threadsafe(void); 213 214/* 215** CAPI3REF: Database Connection Handle 216** KEYWORDS: {database connection} {database connections} 217** 218** Each open SQLite database is represented by a pointer to an instance of 219** the opaque structure named "sqlite3". It is useful to think of an sqlite3 220** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 221** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 222** is its destructor. There are many other interfaces (such as 223** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 224** [sqlite3_busy_timeout()] to name but three) that are methods on an 225** sqlite3 object. 226*/ 227typedef struct sqlite3 sqlite3; 228 229/* 230** CAPI3REF: 64-Bit Integer Types 231** KEYWORDS: sqlite_int64 sqlite_uint64 232** 233** Because there is no cross-platform way to specify 64-bit integer types 234** SQLite includes typedefs for 64-bit signed and unsigned integers. 235** 236** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 237** The sqlite_int64 and sqlite_uint64 types are supported for backwards 238** compatibility only. 239** 240** ^The sqlite3_int64 and sqlite_int64 types can store integer values 241** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 242** sqlite3_uint64 and sqlite_uint64 types can store integer values 243** between 0 and +18446744073709551615 inclusive. 244*/ 245#ifdef SQLITE_INT64_TYPE 246 typedef SQLITE_INT64_TYPE sqlite_int64; 247 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 248#elif defined(_MSC_VER) || defined(__BORLANDC__) 249 typedef __int64 sqlite_int64; 250 typedef unsigned __int64 sqlite_uint64; 251#else 252 typedef long long int sqlite_int64; 253 typedef unsigned long long int sqlite_uint64; 254#endif 255typedef sqlite_int64 sqlite3_int64; 256typedef sqlite_uint64 sqlite3_uint64; 257 258/* 259** If compiling for a processor that lacks floating point support, 260** substitute integer for floating-point. 261*/ 262#ifdef SQLITE_OMIT_FLOATING_POINT 263# define double sqlite3_int64 264#endif 265 266/* 267** CAPI3REF: Closing A Database Connection 268** 269** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 270** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 271** successfully destroyed and all associated resources are deallocated. 272** 273** Applications must [sqlite3_finalize | finalize] all [prepared statements] 274** and [sqlite3_blob_close | close] all [BLOB handles] associated with 275** the [sqlite3] object prior to attempting to close the object. ^If 276** sqlite3_close() is called on a [database connection] that still has 277** outstanding [prepared statements] or [BLOB handles], then it returns 278** SQLITE_BUSY. 279** 280** ^If [sqlite3_close()] is invoked while a transaction is open, 281** the transaction is automatically rolled back. 282** 283** The C parameter to [sqlite3_close(C)] must be either a NULL 284** pointer or an [sqlite3] object pointer obtained 285** from [sqlite3_open()], [sqlite3_open16()], or 286** [sqlite3_open_v2()], and not previously closed. 287** ^Calling sqlite3_close() with a NULL pointer argument is a 288** harmless no-op. 289*/ 290SQLITE_API int sqlite3_close(sqlite3 *); 291 292/* 293** The type for a callback function. 294** This is legacy and deprecated. It is included for historical 295** compatibility and is not documented. 296*/ 297typedef int (*sqlite3_callback)(void*,int,char**, char**); 298 299/* 300** CAPI3REF: One-Step Query Execution Interface 301** 302** The sqlite3_exec() interface is a convenience wrapper around 303** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 304** that allows an application to run multiple statements of SQL 305** without having to use a lot of C code. 306** 307** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 308** semicolon-separate SQL statements passed into its 2nd argument, 309** in the context of the [database connection] passed in as its 1st 310** argument. ^If the callback function of the 3rd argument to 311** sqlite3_exec() is not NULL, then it is invoked for each result row 312** coming out of the evaluated SQL statements. ^The 4th argument to 313** sqlite3_exec() is relayed through to the 1st argument of each 314** callback invocation. ^If the callback pointer to sqlite3_exec() 315** is NULL, then no callback is ever invoked and result rows are 316** ignored. 317** 318** ^If an error occurs while evaluating the SQL statements passed into 319** sqlite3_exec(), then execution of the current statement stops and 320** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 321** is not NULL then any error message is written into memory obtained 322** from [sqlite3_malloc()] and passed back through the 5th parameter. 323** To avoid memory leaks, the application should invoke [sqlite3_free()] 324** on error message strings returned through the 5th parameter of 325** of sqlite3_exec() after the error message string is no longer needed. 326** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 327** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 328** NULL before returning. 329** 330** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 331** routine returns SQLITE_ABORT without invoking the callback again and 332** without running any subsequent SQL statements. 333** 334** ^The 2nd argument to the sqlite3_exec() callback function is the 335** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 336** callback is an array of pointers to strings obtained as if from 337** [sqlite3_column_text()], one for each column. ^If an element of a 338** result row is NULL then the corresponding string pointer for the 339** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 340** sqlite3_exec() callback is an array of pointers to strings where each 341** entry represents the name of corresponding result column as obtained 342** from [sqlite3_column_name()]. 343** 344** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 345** to an empty string, or a pointer that contains only whitespace and/or 346** SQL comments, then no SQL statements are evaluated and the database 347** is not changed. 348** 349** Restrictions: 350** 351** <ul> 352** <li> The application must insure that the 1st parameter to sqlite3_exec() 353** is a valid and open [database connection]. 354** <li> The application must not close [database connection] specified by 355** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 356** <li> The application must not modify the SQL statement text passed into 357** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 358** </ul> 359*/ 360SQLITE_API int sqlite3_exec( 361 sqlite3*, /* An open database */ 362 const char *sql, /* SQL to be evaluated */ 363 int (*callback)(void*,int,char**,char**), /* Callback function */ 364 void *, /* 1st argument to callback */ 365 char **errmsg /* Error msg written here */ 366); 367 368/* 369** CAPI3REF: Result Codes 370** KEYWORDS: SQLITE_OK {error code} {error codes} 371** KEYWORDS: {result code} {result codes} 372** 373** Many SQLite functions return an integer result code from the set shown 374** here in order to indicate success or failure. 375** 376** New error codes may be added in future versions of SQLite. 377** 378** See also: [SQLITE_IOERR_READ | extended result codes], 379** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes]. 380*/ 381#define SQLITE_OK 0 /* Successful result */ 382/* beginning-of-error-codes */ 383#define SQLITE_ERROR 1 /* SQL error or missing database */ 384#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 385#define SQLITE_PERM 3 /* Access permission denied */ 386#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 387#define SQLITE_BUSY 5 /* The database file is locked */ 388#define SQLITE_LOCKED 6 /* A table in the database is locked */ 389#define SQLITE_NOMEM 7 /* A malloc() failed */ 390#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 391#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 392#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 393#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 394#define SQLITE_NOTFOUND 12 /* Unknown opcode in sqlite3_file_control() */ 395#define SQLITE_FULL 13 /* Insertion failed because database is full */ 396#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 397#define SQLITE_PROTOCOL 15 /* Database lock protocol error */ 398#define SQLITE_EMPTY 16 /* Database is empty */ 399#define SQLITE_SCHEMA 17 /* The database schema changed */ 400#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 401#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 402#define SQLITE_MISMATCH 20 /* Data type mismatch */ 403#define SQLITE_MISUSE 21 /* Library used incorrectly */ 404#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 405#define SQLITE_AUTH 23 /* Authorization denied */ 406#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 407#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 408#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 409#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 410#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 411/* end-of-error-codes */ 412 413/* 414** CAPI3REF: Extended Result Codes 415** KEYWORDS: {extended error code} {extended error codes} 416** KEYWORDS: {extended result code} {extended result codes} 417** 418** In its default configuration, SQLite API routines return one of 26 integer 419** [SQLITE_OK | result codes]. However, experience has shown that many of 420** these result codes are too coarse-grained. They do not provide as 421** much information about problems as programmers might like. In an effort to 422** address this, newer versions of SQLite (version 3.3.8 and later) include 423** support for additional result codes that provide more detailed information 424** about errors. The extended result codes are enabled or disabled 425** on a per database connection basis using the 426** [sqlite3_extended_result_codes()] API. 427** 428** Some of the available extended result codes are listed here. 429** One may expect the number of extended result codes will be expand 430** over time. Software that uses extended result codes should expect 431** to see new result codes in future releases of SQLite. 432** 433** The SQLITE_OK result code will never be extended. It will always 434** be exactly zero. 435*/ 436#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 437#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 438#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 439#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 440#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 441#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 442#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 443#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 444#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 445#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 446#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 447#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 448#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 449#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 450#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 451#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 452#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 453#define SQLITE_IOERR_SHMOPEN (SQLITE_IOERR | (18<<8)) 454#define SQLITE_IOERR_SHMSIZE (SQLITE_IOERR | (19<<8)) 455#define SQLITE_IOERR_SHMLOCK (SQLITE_IOERR | (20<<8)) 456#define SQLITE_IOERR_SHMMAP (SQLITE_IOERR | (21<<8)) 457#define SQLITE_IOERR_SEEK (SQLITE_IOERR | (22<<8)) 458#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8)) 459#define SQLITE_BUSY_RECOVERY (SQLITE_BUSY | (1<<8)) 460#define SQLITE_CANTOPEN_NOTEMPDIR (SQLITE_CANTOPEN | (1<<8)) 461#define SQLITE_CORRUPT_VTAB (SQLITE_CORRUPT | (1<<8)) 462#define SQLITE_READONLY_RECOVERY (SQLITE_READONLY | (1<<8)) 463#define SQLITE_READONLY_CANTLOCK (SQLITE_READONLY | (2<<8)) 464#define SQLITE_ABORT_ROLLBACK (SQLITE_ABORT | (2<<8)) 465 466/* 467** CAPI3REF: Flags For File Open Operations 468** 469** These bit values are intended for use in the 470** 3rd parameter to the [sqlite3_open_v2()] interface and 471** in the 4th parameter to the [sqlite3_vfs.xOpen] method. 472*/ 473#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 474#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 475#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 476#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 477#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 478#define SQLITE_OPEN_AUTOPROXY 0x00000020 /* VFS only */ 479#define SQLITE_OPEN_URI 0x00000040 /* Ok for sqlite3_open_v2() */ 480#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 481#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 482#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 483#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 484#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 485#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 486#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 487#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 488#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 489#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 490#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 491#define SQLITE_OPEN_WAL 0x00080000 /* VFS only */ 492 493/* Reserved: 0x00F00000 */ 494 495/* 496** CAPI3REF: Device Characteristics 497** 498** The xDeviceCharacteristics method of the [sqlite3_io_methods] 499** object returns an integer which is a vector of the these 500** bit values expressing I/O characteristics of the mass storage 501** device that holds the file that the [sqlite3_io_methods] 502** refers to. 503** 504** The SQLITE_IOCAP_ATOMIC property means that all writes of 505** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 506** mean that writes of blocks that are nnn bytes in size and 507** are aligned to an address which is an integer multiple of 508** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 509** that when data is appended to a file, the data is appended 510** first then the size of the file is extended, never the other 511** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 512** information is written to disk in the same order as calls 513** to xWrite(). The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that 514** after reboot following a crash or power loss, the only bytes in a 515** file that were written at the application level might have changed 516** and that adjacent bytes, even bytes within the same sector are 517** guaranteed to be unchanged. 518*/ 519#define SQLITE_IOCAP_ATOMIC 0x00000001 520#define SQLITE_IOCAP_ATOMIC512 0x00000002 521#define SQLITE_IOCAP_ATOMIC1K 0x00000004 522#define SQLITE_IOCAP_ATOMIC2K 0x00000008 523#define SQLITE_IOCAP_ATOMIC4K 0x00000010 524#define SQLITE_IOCAP_ATOMIC8K 0x00000020 525#define SQLITE_IOCAP_ATOMIC16K 0x00000040 526#define SQLITE_IOCAP_ATOMIC32K 0x00000080 527#define SQLITE_IOCAP_ATOMIC64K 0x00000100 528#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 529#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 530#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN 0x00000800 531#define SQLITE_IOCAP_POWERSAFE_OVERWRITE 0x00001000 532 533/* 534** CAPI3REF: File Locking Levels 535** 536** SQLite uses one of these integer values as the second 537** argument to calls it makes to the xLock() and xUnlock() methods 538** of an [sqlite3_io_methods] object. 539*/ 540#define SQLITE_LOCK_NONE 0 541#define SQLITE_LOCK_SHARED 1 542#define SQLITE_LOCK_RESERVED 2 543#define SQLITE_LOCK_PENDING 3 544#define SQLITE_LOCK_EXCLUSIVE 4 545 546/* 547** CAPI3REF: Synchronization Type Flags 548** 549** When SQLite invokes the xSync() method of an 550** [sqlite3_io_methods] object it uses a combination of 551** these integer values as the second argument. 552** 553** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 554** sync operation only needs to flush data to mass storage. Inode 555** information need not be flushed. If the lower four bits of the flag 556** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 557** If the lower four bits equal SQLITE_SYNC_FULL, that means 558** to use Mac OS X style fullsync instead of fsync(). 559** 560** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags 561** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL 562** settings. The [synchronous pragma] determines when calls to the 563** xSync VFS method occur and applies uniformly across all platforms. 564** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how 565** energetic or rigorous or forceful the sync operations are and 566** only make a difference on Mac OSX for the default SQLite code. 567** (Third-party VFS implementations might also make the distinction 568** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the 569** operating systems natively supported by SQLite, only Mac OSX 570** cares about the difference.) 571*/ 572#define SQLITE_SYNC_NORMAL 0x00002 573#define SQLITE_SYNC_FULL 0x00003 574#define SQLITE_SYNC_DATAONLY 0x00010 575 576/* 577** CAPI3REF: OS Interface Open File Handle 578** 579** An [sqlite3_file] object represents an open file in the 580** [sqlite3_vfs | OS interface layer]. Individual OS interface 581** implementations will 582** want to subclass this object by appending additional fields 583** for their own use. The pMethods entry is a pointer to an 584** [sqlite3_io_methods] object that defines methods for performing 585** I/O operations on the open file. 586*/ 587typedef struct sqlite3_file sqlite3_file; 588struct sqlite3_file { 589 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 590}; 591 592/* 593** CAPI3REF: OS Interface File Virtual Methods Object 594** 595** Every file opened by the [sqlite3_vfs.xOpen] method populates an 596** [sqlite3_file] object (or, more commonly, a subclass of the 597** [sqlite3_file] object) with a pointer to an instance of this object. 598** This object defines the methods used to perform various operations 599** against the open file represented by the [sqlite3_file] object. 600** 601** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 602** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 603** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed. The 604** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen] 605** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element 606** to NULL. 607** 608** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 609** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 610** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 611** flag may be ORed in to indicate that only the data of the file 612** and not its inode needs to be synced. 613** 614** The integer values to xLock() and xUnlock() are one of 615** <ul> 616** <li> [SQLITE_LOCK_NONE], 617** <li> [SQLITE_LOCK_SHARED], 618** <li> [SQLITE_LOCK_RESERVED], 619** <li> [SQLITE_LOCK_PENDING], or 620** <li> [SQLITE_LOCK_EXCLUSIVE]. 621** </ul> 622** xLock() increases the lock. xUnlock() decreases the lock. 623** The xCheckReservedLock() method checks whether any database connection, 624** either in this process or in some other process, is holding a RESERVED, 625** PENDING, or EXCLUSIVE lock on the file. It returns true 626** if such a lock exists and false otherwise. 627** 628** The xFileControl() method is a generic interface that allows custom 629** VFS implementations to directly control an open file using the 630** [sqlite3_file_control()] interface. The second "op" argument is an 631** integer opcode. The third argument is a generic pointer intended to 632** point to a structure that may contain arguments or space in which to 633** write return values. Potential uses for xFileControl() might be 634** functions to enable blocking locks with timeouts, to change the 635** locking strategy (for example to use dot-file locks), to inquire 636** about the status of a lock, or to break stale locks. The SQLite 637** core reserves all opcodes less than 100 for its own use. 638** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 639** Applications that define a custom xFileControl method should use opcodes 640** greater than 100 to avoid conflicts. VFS implementations should 641** return [SQLITE_NOTFOUND] for file control opcodes that they do not 642** recognize. 643** 644** The xSectorSize() method returns the sector size of the 645** device that underlies the file. The sector size is the 646** minimum write that can be performed without disturbing 647** other bytes in the file. The xDeviceCharacteristics() 648** method returns a bit vector describing behaviors of the 649** underlying device: 650** 651** <ul> 652** <li> [SQLITE_IOCAP_ATOMIC] 653** <li> [SQLITE_IOCAP_ATOMIC512] 654** <li> [SQLITE_IOCAP_ATOMIC1K] 655** <li> [SQLITE_IOCAP_ATOMIC2K] 656** <li> [SQLITE_IOCAP_ATOMIC4K] 657** <li> [SQLITE_IOCAP_ATOMIC8K] 658** <li> [SQLITE_IOCAP_ATOMIC16K] 659** <li> [SQLITE_IOCAP_ATOMIC32K] 660** <li> [SQLITE_IOCAP_ATOMIC64K] 661** <li> [SQLITE_IOCAP_SAFE_APPEND] 662** <li> [SQLITE_IOCAP_SEQUENTIAL] 663** </ul> 664** 665** The SQLITE_IOCAP_ATOMIC property means that all writes of 666** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 667** mean that writes of blocks that are nnn bytes in size and 668** are aligned to an address which is an integer multiple of 669** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 670** that when data is appended to a file, the data is appended 671** first then the size of the file is extended, never the other 672** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 673** information is written to disk in the same order as calls 674** to xWrite(). 675** 676** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 677** in the unread portions of the buffer with zeros. A VFS that 678** fails to zero-fill short reads might seem to work. However, 679** failure to zero-fill short reads will eventually lead to 680** database corruption. 681*/ 682typedef struct sqlite3_io_methods sqlite3_io_methods; 683struct sqlite3_io_methods { 684 int iVersion; 685 int (*xClose)(sqlite3_file*); 686 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 687 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 688 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 689 int (*xSync)(sqlite3_file*, int flags); 690 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 691 int (*xLock)(sqlite3_file*, int); 692 int (*xUnlock)(sqlite3_file*, int); 693 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 694 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 695 int (*xSectorSize)(sqlite3_file*); 696 int (*xDeviceCharacteristics)(sqlite3_file*); 697 /* Methods above are valid for version 1 */ 698 int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**); 699 int (*xShmLock)(sqlite3_file*, int offset, int n, int flags); 700 void (*xShmBarrier)(sqlite3_file*); 701 int (*xShmUnmap)(sqlite3_file*, int deleteFlag); 702 /* Methods above are valid for version 2 */ 703 /* Additional methods may be added in future releases */ 704}; 705 706/* 707** CAPI3REF: Standard File Control Opcodes 708** 709** These integer constants are opcodes for the xFileControl method 710** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 711** interface. 712** 713** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 714** opcode causes the xFileControl method to write the current state of 715** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 716** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 717** into an integer that the pArg argument points to. This capability 718** is used during testing and only needs to be supported when SQLITE_TEST 719** is defined. 720** <ul> 721** <li>[[SQLITE_FCNTL_SIZE_HINT]] 722** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS 723** layer a hint of how large the database file will grow to be during the 724** current transaction. This hint is not guaranteed to be accurate but it 725** is often close. The underlying VFS might choose to preallocate database 726** file space based on this hint in order to help writes to the database 727** file run faster. 728** 729** <li>[[SQLITE_FCNTL_CHUNK_SIZE]] 730** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS 731** extends and truncates the database file in chunks of a size specified 732** by the user. The fourth argument to [sqlite3_file_control()] should 733** point to an integer (type int) containing the new chunk-size to use 734** for the nominated database. Allocating database file space in large 735** chunks (say 1MB at a time), may reduce file-system fragmentation and 736** improve performance on some systems. 737** 738** <li>[[SQLITE_FCNTL_FILE_POINTER]] 739** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer 740** to the [sqlite3_file] object associated with a particular database 741** connection. See the [sqlite3_file_control()] documentation for 742** additional information. 743** 744** <li>[[SQLITE_FCNTL_SYNC_OMITTED]] 745** ^(The [SQLITE_FCNTL_SYNC_OMITTED] opcode is generated internally by 746** SQLite and sent to all VFSes in place of a call to the xSync method 747** when the database connection has [PRAGMA synchronous] set to OFF.)^ 748** Some specialized VFSes need this signal in order to operate correctly 749** when [PRAGMA synchronous | PRAGMA synchronous=OFF] is set, but most 750** VFSes do not need this signal and should silently ignore this opcode. 751** Applications should not call [sqlite3_file_control()] with this 752** opcode as doing so may disrupt the operation of the specialized VFSes 753** that do require it. 754** 755** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]] 756** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic 757** retry counts and intervals for certain disk I/O operations for the 758** windows [VFS] in order to provide robustness in the presence of 759** anti-virus programs. By default, the windows VFS will retry file read, 760** file write, and file delete operations up to 10 times, with a delay 761** of 25 milliseconds before the first retry and with the delay increasing 762** by an additional 25 milliseconds with each subsequent retry. This 763** opcode allows these two values (10 retries and 25 milliseconds of delay) 764** to be adjusted. The values are changed for all database connections 765** within the same process. The argument is a pointer to an array of two 766** integers where the first integer i the new retry count and the second 767** integer is the delay. If either integer is negative, then the setting 768** is not changed but instead the prior value of that setting is written 769** into the array entry, allowing the current retry settings to be 770** interrogated. The zDbName parameter is ignored. 771** 772** <li>[[SQLITE_FCNTL_PERSIST_WAL]] 773** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the 774** persistent [WAL | Write AHead Log] setting. By default, the auxiliary 775** write ahead log and shared memory files used for transaction control 776** are automatically deleted when the latest connection to the database 777** closes. Setting persistent WAL mode causes those files to persist after 778** close. Persisting the files is useful when other processes that do not 779** have write permission on the directory containing the database file want 780** to read the database file, as the WAL and shared memory files must exist 781** in order for the database to be readable. The fourth parameter to 782** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 783** That integer is 0 to disable persistent WAL mode or 1 to enable persistent 784** WAL mode. If the integer is -1, then it is overwritten with the current 785** WAL persistence setting. 786** 787** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]] 788** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the 789** persistent "powersafe-overwrite" or "PSOW" setting. The PSOW setting 790** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the 791** xDeviceCharacteristics methods. The fourth parameter to 792** [sqlite3_file_control()] for this opcode should be a pointer to an integer. 793** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage 794** mode. If the integer is -1, then it is overwritten with the current 795** zero-damage mode setting. 796** 797** <li>[[SQLITE_FCNTL_OVERWRITE]] 798** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening 799** a write transaction to indicate that, unless it is rolled back for some 800** reason, the entire database file will be overwritten by the current 801** transaction. This is used by VACUUM operations. 802** 803** <li>[[SQLITE_FCNTL_VFSNAME]] 804** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of 805** all [VFSes] in the VFS stack. The names are of all VFS shims and the 806** final bottom-level VFS are written into memory obtained from 807** [sqlite3_malloc()] and the result is stored in the char* variable 808** that the fourth parameter of [sqlite3_file_control()] points to. 809** The caller is responsible for freeing the memory when done. As with 810** all file-control actions, there is no guarantee that this will actually 811** do anything. Callers should initialize the char* variable to a NULL 812** pointer in case this file-control is not implemented. This file-control 813** is intended for diagnostic use only. 814** 815** <li>[[SQLITE_FCNTL_PRAGMA]] 816** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 817** file control is sent to the open [sqlite3_file] object corresponding 818** to the database file to which the pragma statement refers. ^The argument 819** to the [SQLITE_FCNTL_PRAGMA] file control is an array of 820** pointers to strings (char**) in which the second element of the array 821** is the name of the pragma and the third element is the argument to the 822** pragma or NULL if the pragma has no argument. ^The handler for an 823** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element 824** of the char** argument point to a string obtained from [sqlite3_mprintf()] 825** or the equivalent and that string will become the result of the pragma or 826** the error message if the pragma fails. ^If the 827** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 828** [PRAGMA] processing continues. ^If the [SQLITE_FCNTL_PRAGMA] 829** file control returns [SQLITE_OK], then the parser assumes that the 830** VFS has handled the PRAGMA itself and the parser generates a no-op 831** prepared statement. ^If the [SQLITE_FCNTL_PRAGMA] file control returns 832** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means 833** that the VFS encountered an error while handling the [PRAGMA] and the 834** compilation of the PRAGMA fails with an error. ^The [SQLITE_FCNTL_PRAGMA] 835** file control occurs at the beginning of pragma statement analysis and so 836** it is able to override built-in [PRAGMA] statements. 837** </ul> 838*/ 839#define SQLITE_FCNTL_LOCKSTATE 1 840#define SQLITE_GET_LOCKPROXYFILE 2 841#define SQLITE_SET_LOCKPROXYFILE 3 842#define SQLITE_LAST_ERRNO 4 843#define SQLITE_FCNTL_SIZE_HINT 5 844#define SQLITE_FCNTL_CHUNK_SIZE 6 845#define SQLITE_FCNTL_FILE_POINTER 7 846#define SQLITE_FCNTL_SYNC_OMITTED 8 847#define SQLITE_FCNTL_WIN32_AV_RETRY 9 848#define SQLITE_FCNTL_PERSIST_WAL 10 849#define SQLITE_FCNTL_OVERWRITE 11 850#define SQLITE_FCNTL_VFSNAME 12 851#define SQLITE_FCNTL_POWERSAFE_OVERWRITE 13 852#define SQLITE_FCNTL_PRAGMA 14 853 854/* 855** CAPI3REF: Mutex Handle 856** 857** The mutex module within SQLite defines [sqlite3_mutex] to be an 858** abstract type for a mutex object. The SQLite core never looks 859** at the internal representation of an [sqlite3_mutex]. It only 860** deals with pointers to the [sqlite3_mutex] object. 861** 862** Mutexes are created using [sqlite3_mutex_alloc()]. 863*/ 864typedef struct sqlite3_mutex sqlite3_mutex; 865 866/* 867** CAPI3REF: OS Interface Object 868** 869** An instance of the sqlite3_vfs object defines the interface between 870** the SQLite core and the underlying operating system. The "vfs" 871** in the name of the object stands for "virtual file system". See 872** the [VFS | VFS documentation] for further information. 873** 874** The value of the iVersion field is initially 1 but may be larger in 875** future versions of SQLite. Additional fields may be appended to this 876** object when the iVersion value is increased. Note that the structure 877** of the sqlite3_vfs object changes in the transaction between 878** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 879** modified. 880** 881** The szOsFile field is the size of the subclassed [sqlite3_file] 882** structure used by this VFS. mxPathname is the maximum length of 883** a pathname in this VFS. 884** 885** Registered sqlite3_vfs objects are kept on a linked list formed by 886** the pNext pointer. The [sqlite3_vfs_register()] 887** and [sqlite3_vfs_unregister()] interfaces manage this list 888** in a thread-safe way. The [sqlite3_vfs_find()] interface 889** searches the list. Neither the application code nor the VFS 890** implementation should use the pNext pointer. 891** 892** The pNext field is the only field in the sqlite3_vfs 893** structure that SQLite will ever modify. SQLite will only access 894** or modify this field while holding a particular static mutex. 895** The application should never modify anything within the sqlite3_vfs 896** object once the object has been registered. 897** 898** The zName field holds the name of the VFS module. The name must 899** be unique across all VFS modules. 900** 901** [[sqlite3_vfs.xOpen]] 902** ^SQLite guarantees that the zFilename parameter to xOpen 903** is either a NULL pointer or string obtained 904** from xFullPathname() with an optional suffix added. 905** ^If a suffix is added to the zFilename parameter, it will 906** consist of a single "-" character followed by no more than 907** 11 alphanumeric and/or "-" characters. 908** ^SQLite further guarantees that 909** the string will be valid and unchanged until xClose() is 910** called. Because of the previous sentence, 911** the [sqlite3_file] can safely store a pointer to the 912** filename if it needs to remember the filename for some reason. 913** If the zFilename parameter to xOpen is a NULL pointer then xOpen 914** must invent its own temporary name for the file. ^Whenever the 915** xFilename parameter is NULL it will also be the case that the 916** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 917** 918** The flags argument to xOpen() includes all bits set in 919** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 920** or [sqlite3_open16()] is used, then flags includes at least 921** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 922** If xOpen() opens a file read-only then it sets *pOutFlags to 923** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 924** 925** ^(SQLite will also add one of the following flags to the xOpen() 926** call, depending on the object being opened: 927** 928** <ul> 929** <li> [SQLITE_OPEN_MAIN_DB] 930** <li> [SQLITE_OPEN_MAIN_JOURNAL] 931** <li> [SQLITE_OPEN_TEMP_DB] 932** <li> [SQLITE_OPEN_TEMP_JOURNAL] 933** <li> [SQLITE_OPEN_TRANSIENT_DB] 934** <li> [SQLITE_OPEN_SUBJOURNAL] 935** <li> [SQLITE_OPEN_MASTER_JOURNAL] 936** <li> [SQLITE_OPEN_WAL] 937** </ul>)^ 938** 939** The file I/O implementation can use the object type flags to 940** change the way it deals with files. For example, an application 941** that does not care about crash recovery or rollback might make 942** the open of a journal file a no-op. Writes to this journal would 943** also be no-ops, and any attempt to read the journal would return 944** SQLITE_IOERR. Or the implementation might recognize that a database 945** file will be doing page-aligned sector reads and writes in a random 946** order and set up its I/O subsystem accordingly. 947** 948** SQLite might also add one of the following flags to the xOpen method: 949** 950** <ul> 951** <li> [SQLITE_OPEN_DELETEONCLOSE] 952** <li> [SQLITE_OPEN_EXCLUSIVE] 953** </ul> 954** 955** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 956** deleted when it is closed. ^The [SQLITE_OPEN_DELETEONCLOSE] 957** will be set for TEMP databases and their journals, transient 958** databases, and subjournals. 959** 960** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 961** with the [SQLITE_OPEN_CREATE] flag, which are both directly 962** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 963** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 964** SQLITE_OPEN_CREATE, is used to indicate that file should always 965** be created, and that it is an error if it already exists. 966** It is <i>not</i> used to indicate the file should be opened 967** for exclusive access. 968** 969** ^At least szOsFile bytes of memory are allocated by SQLite 970** to hold the [sqlite3_file] structure passed as the third 971** argument to xOpen. The xOpen method does not have to 972** allocate the structure; it should just fill it in. Note that 973** the xOpen method must set the sqlite3_file.pMethods to either 974** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 975** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 976** element will be valid after xOpen returns regardless of the success 977** or failure of the xOpen call. 978** 979** [[sqlite3_vfs.xAccess]] 980** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 981** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 982** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 983** to test whether a file is at least readable. The file can be a 984** directory. 985** 986** ^SQLite will always allocate at least mxPathname+1 bytes for the 987** output buffer xFullPathname. The exact size of the output buffer 988** is also passed as a parameter to both methods. If the output buffer 989** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 990** handled as a fatal error by SQLite, vfs implementations should endeavor 991** to prevent this by setting mxPathname to a sufficiently large value. 992** 993** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64() 994** interfaces are not strictly a part of the filesystem, but they are 995** included in the VFS structure for completeness. 996** The xRandomness() function attempts to return nBytes bytes 997** of good-quality randomness into zOut. The return value is 998** the actual number of bytes of randomness obtained. 999** The xSleep() method causes the calling thread to sleep for at 1000** least the number of microseconds given. ^The xCurrentTime() 1001** method returns a Julian Day Number for the current date and time as 1002** a floating point value. 1003** ^The xCurrentTimeInt64() method returns, as an integer, the Julian 1004** Day Number multiplied by 86400000 (the number of milliseconds in 1005** a 24-hour day). 1006** ^SQLite will use the xCurrentTimeInt64() method to get the current 1007** date and time if that method is available (if iVersion is 2 or 1008** greater and the function pointer is not NULL) and will fall back 1009** to xCurrentTime() if xCurrentTimeInt64() is unavailable. 1010** 1011** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces 1012** are not used by the SQLite core. These optional interfaces are provided 1013** by some VFSes to facilitate testing of the VFS code. By overriding 1014** system calls with functions under its control, a test program can 1015** simulate faults and error conditions that would otherwise be difficult 1016** or impossible to induce. The set of system calls that can be overridden 1017** varies from one VFS to another, and from one version of the same VFS to the 1018** next. Applications that use these interfaces must be prepared for any 1019** or all of these interfaces to be NULL or for their behavior to change 1020** from one release to the next. Applications must not attempt to access 1021** any of these methods if the iVersion of the VFS is less than 3. 1022*/ 1023typedef struct sqlite3_vfs sqlite3_vfs; 1024typedef void (*sqlite3_syscall_ptr)(void); 1025struct sqlite3_vfs { 1026 int iVersion; /* Structure version number (currently 3) */ 1027 int szOsFile; /* Size of subclassed sqlite3_file */ 1028 int mxPathname; /* Maximum file pathname length */ 1029 sqlite3_vfs *pNext; /* Next registered VFS */ 1030 const char *zName; /* Name of this virtual file system */ 1031 void *pAppData; /* Pointer to application-specific data */ 1032 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 1033 int flags, int *pOutFlags); 1034 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 1035 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 1036 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 1037 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 1038 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 1039 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 1040 void (*xDlClose)(sqlite3_vfs*, void*); 1041 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 1042 int (*xSleep)(sqlite3_vfs*, int microseconds); 1043 int (*xCurrentTime)(sqlite3_vfs*, double*); 1044 int (*xGetLastError)(sqlite3_vfs*, int, char *); 1045 /* 1046 ** The methods above are in version 1 of the sqlite_vfs object 1047 ** definition. Those that follow are added in version 2 or later 1048 */ 1049 int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*); 1050 /* 1051 ** The methods above are in versions 1 and 2 of the sqlite_vfs object. 1052 ** Those below are for version 3 and greater. 1053 */ 1054 int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr); 1055 sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName); 1056 const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName); 1057 /* 1058 ** The methods above are in versions 1 through 3 of the sqlite_vfs object. 1059 ** New fields may be appended in figure versions. The iVersion 1060 ** value will increment whenever this happens. 1061 */ 1062}; 1063 1064/* 1065** CAPI3REF: Flags for the xAccess VFS method 1066** 1067** These integer constants can be used as the third parameter to 1068** the xAccess method of an [sqlite3_vfs] object. They determine 1069** what kind of permissions the xAccess method is looking for. 1070** With SQLITE_ACCESS_EXISTS, the xAccess method 1071** simply checks whether the file exists. 1072** With SQLITE_ACCESS_READWRITE, the xAccess method 1073** checks whether the named directory is both readable and writable 1074** (in other words, if files can be added, removed, and renamed within 1075** the directory). 1076** The SQLITE_ACCESS_READWRITE constant is currently used only by the 1077** [temp_store_directory pragma], though this could change in a future 1078** release of SQLite. 1079** With SQLITE_ACCESS_READ, the xAccess method 1080** checks whether the file is readable. The SQLITE_ACCESS_READ constant is 1081** currently unused, though it might be used in a future release of 1082** SQLite. 1083*/ 1084#define SQLITE_ACCESS_EXISTS 0 1085#define SQLITE_ACCESS_READWRITE 1 /* Used by PRAGMA temp_store_directory */ 1086#define SQLITE_ACCESS_READ 2 /* Unused */ 1087 1088/* 1089** CAPI3REF: Flags for the xShmLock VFS method 1090** 1091** These integer constants define the various locking operations 1092** allowed by the xShmLock method of [sqlite3_io_methods]. The 1093** following are the only legal combinations of flags to the 1094** xShmLock method: 1095** 1096** <ul> 1097** <li> SQLITE_SHM_LOCK | SQLITE_SHM_SHARED 1098** <li> SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE 1099** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED 1100** <li> SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE 1101** </ul> 1102** 1103** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as 1104** was given no the corresponding lock. 1105** 1106** The xShmLock method can transition between unlocked and SHARED or 1107** between unlocked and EXCLUSIVE. It cannot transition between SHARED 1108** and EXCLUSIVE. 1109*/ 1110#define SQLITE_SHM_UNLOCK 1 1111#define SQLITE_SHM_LOCK 2 1112#define SQLITE_SHM_SHARED 4 1113#define SQLITE_SHM_EXCLUSIVE 8 1114 1115/* 1116** CAPI3REF: Maximum xShmLock index 1117** 1118** The xShmLock method on [sqlite3_io_methods] may use values 1119** between 0 and this upper bound as its "offset" argument. 1120** The SQLite core will never attempt to acquire or release a 1121** lock outside of this range 1122*/ 1123#define SQLITE_SHM_NLOCK 8 1124 1125 1126/* 1127** CAPI3REF: Initialize The SQLite Library 1128** 1129** ^The sqlite3_initialize() routine initializes the 1130** SQLite library. ^The sqlite3_shutdown() routine 1131** deallocates any resources that were allocated by sqlite3_initialize(). 1132** These routines are designed to aid in process initialization and 1133** shutdown on embedded systems. Workstation applications using 1134** SQLite normally do not need to invoke either of these routines. 1135** 1136** A call to sqlite3_initialize() is an "effective" call if it is 1137** the first time sqlite3_initialize() is invoked during the lifetime of 1138** the process, or if it is the first time sqlite3_initialize() is invoked 1139** following a call to sqlite3_shutdown(). ^(Only an effective call 1140** of sqlite3_initialize() does any initialization. All other calls 1141** are harmless no-ops.)^ 1142** 1143** A call to sqlite3_shutdown() is an "effective" call if it is the first 1144** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 1145** an effective call to sqlite3_shutdown() does any deinitialization. 1146** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 1147** 1148** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 1149** is not. The sqlite3_shutdown() interface must only be called from a 1150** single thread. All open [database connections] must be closed and all 1151** other SQLite resources must be deallocated prior to invoking 1152** sqlite3_shutdown(). 1153** 1154** Among other things, ^sqlite3_initialize() will invoke 1155** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 1156** will invoke sqlite3_os_end(). 1157** 1158** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 1159** ^If for some reason, sqlite3_initialize() is unable to initialize 1160** the library (perhaps it is unable to allocate a needed resource such 1161** as a mutex) it returns an [error code] other than [SQLITE_OK]. 1162** 1163** ^The sqlite3_initialize() routine is called internally by many other 1164** SQLite interfaces so that an application usually does not need to 1165** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 1166** calls sqlite3_initialize() so the SQLite library will be automatically 1167** initialized when [sqlite3_open()] is called if it has not be initialized 1168** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 1169** compile-time option, then the automatic calls to sqlite3_initialize() 1170** are omitted and the application must call sqlite3_initialize() directly 1171** prior to using any other SQLite interface. For maximum portability, 1172** it is recommended that applications always invoke sqlite3_initialize() 1173** directly prior to using any other SQLite interface. Future releases 1174** of SQLite may require this. In other words, the behavior exhibited 1175** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 1176** default behavior in some future release of SQLite. 1177** 1178** The sqlite3_os_init() routine does operating-system specific 1179** initialization of the SQLite library. The sqlite3_os_end() 1180** routine undoes the effect of sqlite3_os_init(). Typical tasks 1181** performed by these routines include allocation or deallocation 1182** of static resources, initialization of global variables, 1183** setting up a default [sqlite3_vfs] module, or setting up 1184** a default configuration using [sqlite3_config()]. 1185** 1186** The application should never invoke either sqlite3_os_init() 1187** or sqlite3_os_end() directly. The application should only invoke 1188** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 1189** interface is called automatically by sqlite3_initialize() and 1190** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 1191** implementations for sqlite3_os_init() and sqlite3_os_end() 1192** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 1193** When [custom builds | built for other platforms] 1194** (using the [SQLITE_OS_OTHER=1] compile-time 1195** option) the application must supply a suitable implementation for 1196** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 1197** implementation of sqlite3_os_init() or sqlite3_os_end() 1198** must return [SQLITE_OK] on success and some other [error code] upon 1199** failure. 1200*/ 1201SQLITE_API int sqlite3_initialize(void); 1202SQLITE_API int sqlite3_shutdown(void); 1203SQLITE_API int sqlite3_os_init(void); 1204SQLITE_API int sqlite3_os_end(void); 1205 1206/* 1207** CAPI3REF: Configuring The SQLite Library 1208** 1209** The sqlite3_config() interface is used to make global configuration 1210** changes to SQLite in order to tune SQLite to the specific needs of 1211** the application. The default configuration is recommended for most 1212** applications and so this routine is usually not necessary. It is 1213** provided to support rare applications with unusual needs. 1214** 1215** The sqlite3_config() interface is not threadsafe. The application 1216** must insure that no other SQLite interfaces are invoked by other 1217** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 1218** may only be invoked prior to library initialization using 1219** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 1220** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 1221** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 1222** Note, however, that ^sqlite3_config() can be called as part of the 1223** implementation of an application-defined [sqlite3_os_init()]. 1224** 1225** The first argument to sqlite3_config() is an integer 1226** [configuration option] that determines 1227** what property of SQLite is to be configured. Subsequent arguments 1228** vary depending on the [configuration option] 1229** in the first argument. 1230** 1231** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 1232** ^If the option is unknown or SQLite is unable to set the option 1233** then this routine returns a non-zero [error code]. 1234*/ 1235SQLITE_API int sqlite3_config(int, ...); 1236 1237/* 1238** CAPI3REF: Configure database connections 1239** 1240** The sqlite3_db_config() interface is used to make configuration 1241** changes to a [database connection]. The interface is similar to 1242** [sqlite3_config()] except that the changes apply to a single 1243** [database connection] (specified in the first argument). 1244** 1245** The second argument to sqlite3_db_config(D,V,...) is the 1246** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 1247** that indicates what aspect of the [database connection] is being configured. 1248** Subsequent arguments vary depending on the configuration verb. 1249** 1250** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 1251** the call is considered successful. 1252*/ 1253SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...); 1254 1255/* 1256** CAPI3REF: Memory Allocation Routines 1257** 1258** An instance of this object defines the interface between SQLite 1259** and low-level memory allocation routines. 1260** 1261** This object is used in only one place in the SQLite interface. 1262** A pointer to an instance of this object is the argument to 1263** [sqlite3_config()] when the configuration option is 1264** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 1265** By creating an instance of this object 1266** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 1267** during configuration, an application can specify an alternative 1268** memory allocation subsystem for SQLite to use for all of its 1269** dynamic memory needs. 1270** 1271** Note that SQLite comes with several [built-in memory allocators] 1272** that are perfectly adequate for the overwhelming majority of applications 1273** and that this object is only useful to a tiny minority of applications 1274** with specialized memory allocation requirements. This object is 1275** also used during testing of SQLite in order to specify an alternative 1276** memory allocator that simulates memory out-of-memory conditions in 1277** order to verify that SQLite recovers gracefully from such 1278** conditions. 1279** 1280** The xMalloc, xRealloc, and xFree methods must work like the 1281** malloc(), realloc() and free() functions from the standard C library. 1282** ^SQLite guarantees that the second argument to 1283** xRealloc is always a value returned by a prior call to xRoundup. 1284** 1285** xSize should return the allocated size of a memory allocation 1286** previously obtained from xMalloc or xRealloc. The allocated size 1287** is always at least as big as the requested size but may be larger. 1288** 1289** The xRoundup method returns what would be the allocated size of 1290** a memory allocation given a particular requested size. Most memory 1291** allocators round up memory allocations at least to the next multiple 1292** of 8. Some allocators round up to a larger multiple or to a power of 2. 1293** Every memory allocation request coming in through [sqlite3_malloc()] 1294** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1295** that causes the corresponding memory allocation to fail. 1296** 1297** The xInit method initializes the memory allocator. (For example, 1298** it might allocate any require mutexes or initialize internal data 1299** structures. The xShutdown method is invoked (indirectly) by 1300** [sqlite3_shutdown()] and should deallocate any resources acquired 1301** by xInit. The pAppData pointer is used as the only parameter to 1302** xInit and xShutdown. 1303** 1304** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1305** the xInit method, so the xInit method need not be threadsafe. The 1306** xShutdown method is only called from [sqlite3_shutdown()] so it does 1307** not need to be threadsafe either. For all other methods, SQLite 1308** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1309** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1310** it is by default) and so the methods are automatically serialized. 1311** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1312** methods must be threadsafe or else make their own arrangements for 1313** serialization. 1314** 1315** SQLite will never invoke xInit() more than once without an intervening 1316** call to xShutdown(). 1317*/ 1318typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1319struct sqlite3_mem_methods { 1320 void *(*xMalloc)(int); /* Memory allocation function */ 1321 void (*xFree)(void*); /* Free a prior allocation */ 1322 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1323 int (*xSize)(void*); /* Return the size of an allocation */ 1324 int (*xRoundup)(int); /* Round up request size to allocation size */ 1325 int (*xInit)(void*); /* Initialize the memory allocator */ 1326 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1327 void *pAppData; /* Argument to xInit() and xShutdown() */ 1328}; 1329 1330/* 1331** CAPI3REF: Configuration Options 1332** KEYWORDS: {configuration option} 1333** 1334** These constants are the available integer configuration options that 1335** can be passed as the first argument to the [sqlite3_config()] interface. 1336** 1337** New configuration options may be added in future releases of SQLite. 1338** Existing configuration options might be discontinued. Applications 1339** should check the return code from [sqlite3_config()] to make sure that 1340** the call worked. The [sqlite3_config()] interface will return a 1341** non-zero [error code] if a discontinued or unsupported configuration option 1342** is invoked. 1343** 1344** <dl> 1345** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1346** <dd>There are no arguments to this option. ^This option sets the 1347** [threading mode] to Single-thread. In other words, it disables 1348** all mutexing and puts SQLite into a mode where it can only be used 1349** by a single thread. ^If SQLite is compiled with 1350** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1351** it is not possible to change the [threading mode] from its default 1352** value of Single-thread and so [sqlite3_config()] will return 1353** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1354** configuration option.</dd> 1355** 1356** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1357** <dd>There are no arguments to this option. ^This option sets the 1358** [threading mode] to Multi-thread. In other words, it disables 1359** mutexing on [database connection] and [prepared statement] objects. 1360** The application is responsible for serializing access to 1361** [database connections] and [prepared statements]. But other mutexes 1362** are enabled so that SQLite will be safe to use in a multi-threaded 1363** environment as long as no two threads attempt to use the same 1364** [database connection] at the same time. ^If SQLite is compiled with 1365** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1366** it is not possible to set the Multi-thread [threading mode] and 1367** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1368** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1369** 1370** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt> 1371** <dd>There are no arguments to this option. ^This option sets the 1372** [threading mode] to Serialized. In other words, this option enables 1373** all mutexes including the recursive 1374** mutexes on [database connection] and [prepared statement] objects. 1375** In this mode (which is the default when SQLite is compiled with 1376** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1377** to [database connections] and [prepared statements] so that the 1378** application is free to use the same [database connection] or the 1379** same [prepared statement] in different threads at the same time. 1380** ^If SQLite is compiled with 1381** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1382** it is not possible to set the Serialized [threading mode] and 1383** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1384** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1385** 1386** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt> 1387** <dd> ^(This option takes a single argument which is a pointer to an 1388** instance of the [sqlite3_mem_methods] structure. The argument specifies 1389** alternative low-level memory allocation routines to be used in place of 1390** the memory allocation routines built into SQLite.)^ ^SQLite makes 1391** its own private copy of the content of the [sqlite3_mem_methods] structure 1392** before the [sqlite3_config()] call returns.</dd> 1393** 1394** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt> 1395** <dd> ^(This option takes a single argument which is a pointer to an 1396** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1397** structure is filled with the currently defined memory allocation routines.)^ 1398** This option can be used to overload the default memory allocation 1399** routines with a wrapper that simulations memory allocation failure or 1400** tracks memory usage, for example. </dd> 1401** 1402** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1403** <dd> ^This option takes single argument of type int, interpreted as a 1404** boolean, which enables or disables the collection of memory allocation 1405** statistics. ^(When memory allocation statistics are disabled, the 1406** following SQLite interfaces become non-operational: 1407** <ul> 1408** <li> [sqlite3_memory_used()] 1409** <li> [sqlite3_memory_highwater()] 1410** <li> [sqlite3_soft_heap_limit64()] 1411** <li> [sqlite3_status()] 1412** </ul>)^ 1413** ^Memory allocation statistics are enabled by default unless SQLite is 1414** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1415** allocation statistics are disabled by default. 1416** </dd> 1417** 1418** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt> 1419** <dd> ^This option specifies a static memory buffer that SQLite can use for 1420** scratch memory. There are three arguments: A pointer an 8-byte 1421** aligned memory buffer from which the scratch allocations will be 1422** drawn, the size of each scratch allocation (sz), 1423** and the maximum number of scratch allocations (N). The sz 1424** argument must be a multiple of 16. 1425** The first argument must be a pointer to an 8-byte aligned buffer 1426** of at least sz*N bytes of memory. 1427** ^SQLite will use no more than two scratch buffers per thread. So 1428** N should be set to twice the expected maximum number of threads. 1429** ^SQLite will never require a scratch buffer that is more than 6 1430** times the database page size. ^If SQLite needs needs additional 1431** scratch memory beyond what is provided by this configuration option, then 1432** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1433** 1434** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt> 1435** <dd> ^This option specifies a static memory buffer that SQLite can use for 1436** the database page cache with the default page cache implementation. 1437** This configuration should not be used if an application-define page 1438** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option. 1439** There are three arguments to this option: A pointer to 8-byte aligned 1440** memory, the size of each page buffer (sz), and the number of pages (N). 1441** The sz argument should be the size of the largest database page 1442** (a power of two between 512 and 32768) plus a little extra for each 1443** page header. ^The page header size is 20 to 40 bytes depending on 1444** the host architecture. ^It is harmless, apart from the wasted memory, 1445** to make sz a little too large. The first 1446** argument should point to an allocation of at least sz*N bytes of memory. 1447** ^SQLite will use the memory provided by the first argument to satisfy its 1448** memory needs for the first N pages that it adds to cache. ^If additional 1449** page cache memory is needed beyond what is provided by this option, then 1450** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1451** The pointer in the first argument must 1452** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1453** will be undefined.</dd> 1454** 1455** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt> 1456** <dd> ^This option specifies a static memory buffer that SQLite will use 1457** for all of its dynamic memory allocation needs beyond those provided 1458** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1459** There are three arguments: An 8-byte aligned pointer to the memory, 1460** the number of bytes in the memory buffer, and the minimum allocation size. 1461** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1462** to using its default memory allocator (the system malloc() implementation), 1463** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1464** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1465** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1466** allocator is engaged to handle all of SQLites memory allocation needs. 1467** The first pointer (the memory pointer) must be aligned to an 8-byte 1468** boundary or subsequent behavior of SQLite will be undefined. 1469** The minimum allocation size is capped at 2**12. Reasonable values 1470** for the minimum allocation size are 2**5 through 2**8.</dd> 1471** 1472** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt> 1473** <dd> ^(This option takes a single argument which is a pointer to an 1474** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1475** alternative low-level mutex routines to be used in place 1476** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1477** content of the [sqlite3_mutex_methods] structure before the call to 1478** [sqlite3_config()] returns. ^If SQLite is compiled with 1479** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1480** the entire mutexing subsystem is omitted from the build and hence calls to 1481** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1482** return [SQLITE_ERROR].</dd> 1483** 1484** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt> 1485** <dd> ^(This option takes a single argument which is a pointer to an 1486** instance of the [sqlite3_mutex_methods] structure. The 1487** [sqlite3_mutex_methods] 1488** structure is filled with the currently defined mutex routines.)^ 1489** This option can be used to overload the default mutex allocation 1490** routines with a wrapper used to track mutex usage for performance 1491** profiling or testing, for example. ^If SQLite is compiled with 1492** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1493** the entire mutexing subsystem is omitted from the build and hence calls to 1494** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1495** return [SQLITE_ERROR].</dd> 1496** 1497** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1498** <dd> ^(This option takes two arguments that determine the default 1499** memory allocation for the lookaside memory allocator on each 1500** [database connection]. The first argument is the 1501** size of each lookaside buffer slot and the second is the number of 1502** slots allocated to each database connection.)^ ^(This option sets the 1503** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1504** verb to [sqlite3_db_config()] can be used to change the lookaside 1505** configuration on individual connections.)^ </dd> 1506** 1507** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt> 1508** <dd> ^(This option takes a single argument which is a pointer to 1509** an [sqlite3_pcache_methods2] object. This object specifies the interface 1510** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1511** object and uses it for page cache memory allocations.</dd> 1512** 1513** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt> 1514** <dd> ^(This option takes a single argument which is a pointer to an 1515** [sqlite3_pcache_methods2] object. SQLite copies of the current 1516** page cache implementation into that object.)^ </dd> 1517** 1518** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt> 1519** <dd> ^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a 1520** function with a call signature of void(*)(void*,int,const char*), 1521** and a pointer to void. ^If the function pointer is not NULL, it is 1522** invoked by [sqlite3_log()] to process each logging event. ^If the 1523** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op. 1524** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is 1525** passed through as the first parameter to the application-defined logger 1526** function whenever that function is invoked. ^The second parameter to 1527** the logger function is a copy of the first parameter to the corresponding 1528** [sqlite3_log()] call and is intended to be a [result code] or an 1529** [extended result code]. ^The third parameter passed to the logger is 1530** log message after formatting via [sqlite3_snprintf()]. 1531** The SQLite logging interface is not reentrant; the logger function 1532** supplied by the application must not invoke any SQLite interface. 1533** In a multi-threaded application, the application-defined logger 1534** function must be threadsafe. </dd> 1535** 1536** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI 1537** <dd> This option takes a single argument of type int. If non-zero, then 1538** URI handling is globally enabled. If the parameter is zero, then URI handling 1539** is globally disabled. If URI handling is globally enabled, all filenames 1540** passed to [sqlite3_open()], [sqlite3_open_v2()], [sqlite3_open16()] or 1541** specified as part of [ATTACH] commands are interpreted as URIs, regardless 1542** of whether or not the [SQLITE_OPEN_URI] flag is set when the database 1543** connection is opened. If it is globally disabled, filenames are 1544** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the 1545** database connection is opened. By default, URI handling is globally 1546** disabled. The default value may be changed by compiling with the 1547** [SQLITE_USE_URI] symbol defined. 1548** 1549** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]] 1550** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFNIG_GETPCACHE 1551** <dd> These options are obsolete and should not be used by new code. 1552** They are retained for backwards compatibility but are now no-ops. 1553** </dl> 1554*/ 1555#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1556#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1557#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1558#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1559#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1560#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1561#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1562#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1563#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1564#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1565#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1566/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1567#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1568#define SQLITE_CONFIG_PCACHE 14 /* no-op */ 1569#define SQLITE_CONFIG_GETPCACHE 15 /* no-op */ 1570#define SQLITE_CONFIG_LOG 16 /* xFunc, void* */ 1571#define SQLITE_CONFIG_URI 17 /* int */ 1572#define SQLITE_CONFIG_PCACHE2 18 /* sqlite3_pcache_methods2* */ 1573#define SQLITE_CONFIG_GETPCACHE2 19 /* sqlite3_pcache_methods2* */ 1574 1575/* 1576** CAPI3REF: Database Connection Configuration Options 1577** 1578** These constants are the available integer configuration options that 1579** can be passed as the second argument to the [sqlite3_db_config()] interface. 1580** 1581** New configuration options may be added in future releases of SQLite. 1582** Existing configuration options might be discontinued. Applications 1583** should check the return code from [sqlite3_db_config()] to make sure that 1584** the call worked. ^The [sqlite3_db_config()] interface will return a 1585** non-zero [error code] if a discontinued or unsupported configuration option 1586** is invoked. 1587** 1588** <dl> 1589** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1590** <dd> ^This option takes three additional arguments that determine the 1591** [lookaside memory allocator] configuration for the [database connection]. 1592** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1593** pointer to a memory buffer to use for lookaside memory. 1594** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1595** may be NULL in which case SQLite will allocate the 1596** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1597** size of each lookaside buffer slot. ^The third argument is the number of 1598** slots. The size of the buffer in the first argument must be greater than 1599** or equal to the product of the second and third arguments. The buffer 1600** must be aligned to an 8-byte boundary. ^If the second argument to 1601** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1602** rounded down to the next smaller multiple of 8. ^(The lookaside memory 1603** configuration for a database connection can only be changed when that 1604** connection is not currently using lookaside memory, or in other words 1605** when the "current value" returned by 1606** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero. 1607** Any attempt to change the lookaside memory configuration when lookaside 1608** memory is in use leaves the configuration unchanged and returns 1609** [SQLITE_BUSY].)^</dd> 1610** 1611** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt> 1612** <dd> ^This option is used to enable or disable the enforcement of 1613** [foreign key constraints]. There should be two additional arguments. 1614** The first argument is an integer which is 0 to disable FK enforcement, 1615** positive to enable FK enforcement or negative to leave FK enforcement 1616** unchanged. The second parameter is a pointer to an integer into which 1617** is written 0 or 1 to indicate whether FK enforcement is off or on 1618** following this call. The second parameter may be a NULL pointer, in 1619** which case the FK enforcement setting is not reported back. </dd> 1620** 1621** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt> 1622** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers]. 1623** There should be two additional arguments. 1624** The first argument is an integer which is 0 to disable triggers, 1625** positive to enable triggers or negative to leave the setting unchanged. 1626** The second parameter is a pointer to an integer into which 1627** is written 0 or 1 to indicate whether triggers are disabled or enabled 1628** following this call. The second parameter may be a NULL pointer, in 1629** which case the trigger setting is not reported back. </dd> 1630** 1631** </dl> 1632*/ 1633#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1634#define SQLITE_DBCONFIG_ENABLE_FKEY 1002 /* int int* */ 1635#define SQLITE_DBCONFIG_ENABLE_TRIGGER 1003 /* int int* */ 1636 1637 1638/* 1639** CAPI3REF: Enable Or Disable Extended Result Codes 1640** 1641** ^The sqlite3_extended_result_codes() routine enables or disables the 1642** [extended result codes] feature of SQLite. ^The extended result 1643** codes are disabled by default for historical compatibility. 1644*/ 1645SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff); 1646 1647/* 1648** CAPI3REF: Last Insert Rowid 1649** 1650** ^Each entry in an SQLite table has a unique 64-bit signed 1651** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1652** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1653** names are not also used by explicitly declared columns. ^If 1654** the table has a column of type [INTEGER PRIMARY KEY] then that column 1655** is another alias for the rowid. 1656** 1657** ^This routine returns the [rowid] of the most recent 1658** successful [INSERT] into the database from the [database connection] 1659** in the first argument. ^As of SQLite version 3.7.7, this routines 1660** records the last insert rowid of both ordinary tables and [virtual tables]. 1661** ^If no successful [INSERT]s 1662** have ever occurred on that database connection, zero is returned. 1663** 1664** ^(If an [INSERT] occurs within a trigger or within a [virtual table] 1665** method, then this routine will return the [rowid] of the inserted 1666** row as long as the trigger or virtual table method is running. 1667** But once the trigger or virtual table method ends, the value returned 1668** by this routine reverts to what it was before the trigger or virtual 1669** table method began.)^ 1670** 1671** ^An [INSERT] that fails due to a constraint violation is not a 1672** successful [INSERT] and does not change the value returned by this 1673** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1674** and INSERT OR ABORT make no changes to the return value of this 1675** routine when their insertion fails. ^(When INSERT OR REPLACE 1676** encounters a constraint violation, it does not fail. The 1677** INSERT continues to completion after deleting rows that caused 1678** the constraint problem so INSERT OR REPLACE will always change 1679** the return value of this interface.)^ 1680** 1681** ^For the purposes of this routine, an [INSERT] is considered to 1682** be successful even if it is subsequently rolled back. 1683** 1684** This function is accessible to SQL statements via the 1685** [last_insert_rowid() SQL function]. 1686** 1687** If a separate thread performs a new [INSERT] on the same 1688** database connection while the [sqlite3_last_insert_rowid()] 1689** function is running and thus changes the last insert [rowid], 1690** then the value returned by [sqlite3_last_insert_rowid()] is 1691** unpredictable and might not equal either the old or the new 1692** last insert [rowid]. 1693*/ 1694SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1695 1696/* 1697** CAPI3REF: Count The Number Of Rows Modified 1698** 1699** ^This function returns the number of database rows that were changed 1700** or inserted or deleted by the most recently completed SQL statement 1701** on the [database connection] specified by the first parameter. 1702** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1703** or [DELETE] statement are counted. Auxiliary changes caused by 1704** triggers or [foreign key actions] are not counted.)^ Use the 1705** [sqlite3_total_changes()] function to find the total number of changes 1706** including changes caused by triggers and foreign key actions. 1707** 1708** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1709** are not counted. Only real table changes are counted. 1710** 1711** ^(A "row change" is a change to a single row of a single table 1712** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1713** are changed as side effects of [REPLACE] constraint resolution, 1714** rollback, ABORT processing, [DROP TABLE], or by any other 1715** mechanisms do not count as direct row changes.)^ 1716** 1717** A "trigger context" is a scope of execution that begins and 1718** ends with the script of a [CREATE TRIGGER | trigger]. 1719** Most SQL statements are 1720** evaluated outside of any trigger. This is the "top level" 1721** trigger context. If a trigger fires from the top level, a 1722** new trigger context is entered for the duration of that one 1723** trigger. Subtriggers create subcontexts for their duration. 1724** 1725** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1726** not create a new trigger context. 1727** 1728** ^This function returns the number of direct row changes in the 1729** most recent INSERT, UPDATE, or DELETE statement within the same 1730** trigger context. 1731** 1732** ^Thus, when called from the top level, this function returns the 1733** number of changes in the most recent INSERT, UPDATE, or DELETE 1734** that also occurred at the top level. ^(Within the body of a trigger, 1735** the sqlite3_changes() interface can be called to find the number of 1736** changes in the most recently completed INSERT, UPDATE, or DELETE 1737** statement within the body of the same trigger. 1738** However, the number returned does not include changes 1739** caused by subtriggers since those have their own context.)^ 1740** 1741** See also the [sqlite3_total_changes()] interface, the 1742** [count_changes pragma], and the [changes() SQL function]. 1743** 1744** If a separate thread makes changes on the same database connection 1745** while [sqlite3_changes()] is running then the value returned 1746** is unpredictable and not meaningful. 1747*/ 1748SQLITE_API int sqlite3_changes(sqlite3*); 1749 1750/* 1751** CAPI3REF: Total Number Of Rows Modified 1752** 1753** ^This function returns the number of row changes caused by [INSERT], 1754** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1755** ^(The count returned by sqlite3_total_changes() includes all changes 1756** from all [CREATE TRIGGER | trigger] contexts and changes made by 1757** [foreign key actions]. However, 1758** the count does not include changes used to implement [REPLACE] constraints, 1759** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1760** count does not include rows of views that fire an [INSTEAD OF trigger], 1761** though if the INSTEAD OF trigger makes changes of its own, those changes 1762** are counted.)^ 1763** ^The sqlite3_total_changes() function counts the changes as soon as 1764** the statement that makes them is completed (when the statement handle 1765** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1766** 1767** See also the [sqlite3_changes()] interface, the 1768** [count_changes pragma], and the [total_changes() SQL function]. 1769** 1770** If a separate thread makes changes on the same database connection 1771** while [sqlite3_total_changes()] is running then the value 1772** returned is unpredictable and not meaningful. 1773*/ 1774SQLITE_API int sqlite3_total_changes(sqlite3*); 1775 1776/* 1777** CAPI3REF: Interrupt A Long-Running Query 1778** 1779** ^This function causes any pending database operation to abort and 1780** return at its earliest opportunity. This routine is typically 1781** called in response to a user action such as pressing "Cancel" 1782** or Ctrl-C where the user wants a long query operation to halt 1783** immediately. 1784** 1785** ^It is safe to call this routine from a thread different from the 1786** thread that is currently running the database operation. But it 1787** is not safe to call this routine with a [database connection] that 1788** is closed or might close before sqlite3_interrupt() returns. 1789** 1790** ^If an SQL operation is very nearly finished at the time when 1791** sqlite3_interrupt() is called, then it might not have an opportunity 1792** to be interrupted and might continue to completion. 1793** 1794** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1795** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1796** that is inside an explicit transaction, then the entire transaction 1797** will be rolled back automatically. 1798** 1799** ^The sqlite3_interrupt(D) call is in effect until all currently running 1800** SQL statements on [database connection] D complete. ^Any new SQL statements 1801** that are started after the sqlite3_interrupt() call and before the 1802** running statements reaches zero are interrupted as if they had been 1803** running prior to the sqlite3_interrupt() call. ^New SQL statements 1804** that are started after the running statement count reaches zero are 1805** not effected by the sqlite3_interrupt(). 1806** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1807** SQL statements is a no-op and has no effect on SQL statements 1808** that are started after the sqlite3_interrupt() call returns. 1809** 1810** If the database connection closes while [sqlite3_interrupt()] 1811** is running then bad things will likely happen. 1812*/ 1813SQLITE_API void sqlite3_interrupt(sqlite3*); 1814 1815/* 1816** CAPI3REF: Determine If An SQL Statement Is Complete 1817** 1818** These routines are useful during command-line input to determine if the 1819** currently entered text seems to form a complete SQL statement or 1820** if additional input is needed before sending the text into 1821** SQLite for parsing. ^These routines return 1 if the input string 1822** appears to be a complete SQL statement. ^A statement is judged to be 1823** complete if it ends with a semicolon token and is not a prefix of a 1824** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1825** string literals or quoted identifier names or comments are not 1826** independent tokens (they are part of the token in which they are 1827** embedded) and thus do not count as a statement terminator. ^Whitespace 1828** and comments that follow the final semicolon are ignored. 1829** 1830** ^These routines return 0 if the statement is incomplete. ^If a 1831** memory allocation fails, then SQLITE_NOMEM is returned. 1832** 1833** ^These routines do not parse the SQL statements thus 1834** will not detect syntactically incorrect SQL. 1835** 1836** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1837** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1838** automatically by sqlite3_complete16(). If that initialization fails, 1839** then the return value from sqlite3_complete16() will be non-zero 1840** regardless of whether or not the input SQL is complete.)^ 1841** 1842** The input to [sqlite3_complete()] must be a zero-terminated 1843** UTF-8 string. 1844** 1845** The input to [sqlite3_complete16()] must be a zero-terminated 1846** UTF-16 string in native byte order. 1847*/ 1848SQLITE_API int sqlite3_complete(const char *sql); 1849SQLITE_API int sqlite3_complete16(const void *sql); 1850 1851/* 1852** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1853** 1854** ^This routine sets a callback function that might be invoked whenever 1855** an attempt is made to open a database table that another thread 1856** or process has locked. 1857** 1858** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1859** is returned immediately upon encountering the lock. ^If the busy callback 1860** is not NULL, then the callback might be invoked with two arguments. 1861** 1862** ^The first argument to the busy handler is a copy of the void* pointer which 1863** is the third argument to sqlite3_busy_handler(). ^The second argument to 1864** the busy handler callback is the number of times that the busy handler has 1865** been invoked for this locking event. ^If the 1866** busy callback returns 0, then no additional attempts are made to 1867** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1868** ^If the callback returns non-zero, then another attempt 1869** is made to open the database for reading and the cycle repeats. 1870** 1871** The presence of a busy handler does not guarantee that it will be invoked 1872** when there is lock contention. ^If SQLite determines that invoking the busy 1873** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1874** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1875** Consider a scenario where one process is holding a read lock that 1876** it is trying to promote to a reserved lock and 1877** a second process is holding a reserved lock that it is trying 1878** to promote to an exclusive lock. The first process cannot proceed 1879** because it is blocked by the second and the second process cannot 1880** proceed because it is blocked by the first. If both processes 1881** invoke the busy handlers, neither will make any progress. Therefore, 1882** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1883** will induce the first process to release its read lock and allow 1884** the second process to proceed. 1885** 1886** ^The default busy callback is NULL. 1887** 1888** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1889** when SQLite is in the middle of a large transaction where all the 1890** changes will not fit into the in-memory cache. SQLite will 1891** already hold a RESERVED lock on the database file, but it needs 1892** to promote this lock to EXCLUSIVE so that it can spill cache 1893** pages into the database file without harm to concurrent 1894** readers. ^If it is unable to promote the lock, then the in-memory 1895** cache will be left in an inconsistent state and so the error 1896** code is promoted from the relatively benign [SQLITE_BUSY] to 1897** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1898** forces an automatic rollback of the changes. See the 1899** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1900** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1901** this is important. 1902** 1903** ^(There can only be a single busy handler defined for each 1904** [database connection]. Setting a new busy handler clears any 1905** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1906** will also set or clear the busy handler. 1907** 1908** The busy callback should not take any actions which modify the 1909** database connection that invoked the busy handler. Any such actions 1910** result in undefined behavior. 1911** 1912** A busy handler must not close the database connection 1913** or [prepared statement] that invoked the busy handler. 1914*/ 1915SQLITE_API int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1916 1917/* 1918** CAPI3REF: Set A Busy Timeout 1919** 1920** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1921** for a specified amount of time when a table is locked. ^The handler 1922** will sleep multiple times until at least "ms" milliseconds of sleeping 1923** have accumulated. ^After at least "ms" milliseconds of sleeping, 1924** the handler returns 0 which causes [sqlite3_step()] to return 1925** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1926** 1927** ^Calling this routine with an argument less than or equal to zero 1928** turns off all busy handlers. 1929** 1930** ^(There can only be a single busy handler for a particular 1931** [database connection] any any given moment. If another busy handler 1932** was defined (using [sqlite3_busy_handler()]) prior to calling 1933** this routine, that other busy handler is cleared.)^ 1934*/ 1935SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms); 1936 1937/* 1938** CAPI3REF: Convenience Routines For Running Queries 1939** 1940** This is a legacy interface that is preserved for backwards compatibility. 1941** Use of this interface is not recommended. 1942** 1943** Definition: A <b>result table</b> is memory data structure created by the 1944** [sqlite3_get_table()] interface. A result table records the 1945** complete query results from one or more queries. 1946** 1947** The table conceptually has a number of rows and columns. But 1948** these numbers are not part of the result table itself. These 1949** numbers are obtained separately. Let N be the number of rows 1950** and M be the number of columns. 1951** 1952** A result table is an array of pointers to zero-terminated UTF-8 strings. 1953** There are (N+1)*M elements in the array. The first M pointers point 1954** to zero-terminated strings that contain the names of the columns. 1955** The remaining entries all point to query results. NULL values result 1956** in NULL pointers. All other values are in their UTF-8 zero-terminated 1957** string representation as returned by [sqlite3_column_text()]. 1958** 1959** A result table might consist of one or more memory allocations. 1960** It is not safe to pass a result table directly to [sqlite3_free()]. 1961** A result table should be deallocated using [sqlite3_free_table()]. 1962** 1963** ^(As an example of the result table format, suppose a query result 1964** is as follows: 1965** 1966** <blockquote><pre> 1967** Name | Age 1968** ----------------------- 1969** Alice | 43 1970** Bob | 28 1971** Cindy | 21 1972** </pre></blockquote> 1973** 1974** There are two column (M==2) and three rows (N==3). Thus the 1975** result table has 8 entries. Suppose the result table is stored 1976** in an array names azResult. Then azResult holds this content: 1977** 1978** <blockquote><pre> 1979** azResult[0] = "Name"; 1980** azResult[1] = "Age"; 1981** azResult[2] = "Alice"; 1982** azResult[3] = "43"; 1983** azResult[4] = "Bob"; 1984** azResult[5] = "28"; 1985** azResult[6] = "Cindy"; 1986** azResult[7] = "21"; 1987** </pre></blockquote>)^ 1988** 1989** ^The sqlite3_get_table() function evaluates one or more 1990** semicolon-separated SQL statements in the zero-terminated UTF-8 1991** string of its 2nd parameter and returns a result table to the 1992** pointer given in its 3rd parameter. 1993** 1994** After the application has finished with the result from sqlite3_get_table(), 1995** it must pass the result table pointer to sqlite3_free_table() in order to 1996** release the memory that was malloced. Because of the way the 1997** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1998** function must not try to call [sqlite3_free()] directly. Only 1999** [sqlite3_free_table()] is able to release the memory properly and safely. 2000** 2001** The sqlite3_get_table() interface is implemented as a wrapper around 2002** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 2003** to any internal data structures of SQLite. It uses only the public 2004** interface defined here. As a consequence, errors that occur in the 2005** wrapper layer outside of the internal [sqlite3_exec()] call are not 2006** reflected in subsequent calls to [sqlite3_errcode()] or 2007** [sqlite3_errmsg()]. 2008*/ 2009SQLITE_API int sqlite3_get_table( 2010 sqlite3 *db, /* An open database */ 2011 const char *zSql, /* SQL to be evaluated */ 2012 char ***pazResult, /* Results of the query */ 2013 int *pnRow, /* Number of result rows written here */ 2014 int *pnColumn, /* Number of result columns written here */ 2015 char **pzErrmsg /* Error msg written here */ 2016); 2017SQLITE_API void sqlite3_free_table(char **result); 2018 2019/* 2020** CAPI3REF: Formatted String Printing Functions 2021** 2022** These routines are work-alikes of the "printf()" family of functions 2023** from the standard C library. 2024** 2025** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 2026** results into memory obtained from [sqlite3_malloc()]. 2027** The strings returned by these two routines should be 2028** released by [sqlite3_free()]. ^Both routines return a 2029** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 2030** memory to hold the resulting string. 2031** 2032** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from 2033** the standard C library. The result is written into the 2034** buffer supplied as the second parameter whose size is given by 2035** the first parameter. Note that the order of the 2036** first two parameters is reversed from snprintf().)^ This is an 2037** historical accident that cannot be fixed without breaking 2038** backwards compatibility. ^(Note also that sqlite3_snprintf() 2039** returns a pointer to its buffer instead of the number of 2040** characters actually written into the buffer.)^ We admit that 2041** the number of characters written would be a more useful return 2042** value but we cannot change the implementation of sqlite3_snprintf() 2043** now without breaking compatibility. 2044** 2045** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 2046** guarantees that the buffer is always zero-terminated. ^The first 2047** parameter "n" is the total size of the buffer, including space for 2048** the zero terminator. So the longest string that can be completely 2049** written will be n-1 characters. 2050** 2051** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf(). 2052** 2053** These routines all implement some additional formatting 2054** options that are useful for constructing SQL statements. 2055** All of the usual printf() formatting options apply. In addition, there 2056** is are "%q", "%Q", and "%z" options. 2057** 2058** ^(The %q option works like %s in that it substitutes a nul-terminated 2059** string from the argument list. But %q also doubles every '\'' character. 2060** %q is designed for use inside a string literal.)^ By doubling each '\'' 2061** character it escapes that character and allows it to be inserted into 2062** the string. 2063** 2064** For example, assume the string variable zText contains text as follows: 2065** 2066** <blockquote><pre> 2067** char *zText = "It's a happy day!"; 2068** </pre></blockquote> 2069** 2070** One can use this text in an SQL statement as follows: 2071** 2072** <blockquote><pre> 2073** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 2074** sqlite3_exec(db, zSQL, 0, 0, 0); 2075** sqlite3_free(zSQL); 2076** </pre></blockquote> 2077** 2078** Because the %q format string is used, the '\'' character in zText 2079** is escaped and the SQL generated is as follows: 2080** 2081** <blockquote><pre> 2082** INSERT INTO table1 VALUES('It''s a happy day!') 2083** </pre></blockquote> 2084** 2085** This is correct. Had we used %s instead of %q, the generated SQL 2086** would have looked like this: 2087** 2088** <blockquote><pre> 2089** INSERT INTO table1 VALUES('It's a happy day!'); 2090** </pre></blockquote> 2091** 2092** This second example is an SQL syntax error. As a general rule you should 2093** always use %q instead of %s when inserting text into a string literal. 2094** 2095** ^(The %Q option works like %q except it also adds single quotes around 2096** the outside of the total string. Additionally, if the parameter in the 2097** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 2098** single quotes).)^ So, for example, one could say: 2099** 2100** <blockquote><pre> 2101** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 2102** sqlite3_exec(db, zSQL, 0, 0, 0); 2103** sqlite3_free(zSQL); 2104** </pre></blockquote> 2105** 2106** The code above will render a correct SQL statement in the zSQL 2107** variable even if the zText variable is a NULL pointer. 2108** 2109** ^(The "%z" formatting option works like "%s" but with the 2110** addition that after the string has been read and copied into 2111** the result, [sqlite3_free()] is called on the input string.)^ 2112*/ 2113SQLITE_API char *sqlite3_mprintf(const char*,...); 2114SQLITE_API char *sqlite3_vmprintf(const char*, va_list); 2115SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...); 2116SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list); 2117 2118/* 2119** CAPI3REF: Memory Allocation Subsystem 2120** 2121** The SQLite core uses these three routines for all of its own 2122** internal memory allocation needs. "Core" in the previous sentence 2123** does not include operating-system specific VFS implementation. The 2124** Windows VFS uses native malloc() and free() for some operations. 2125** 2126** ^The sqlite3_malloc() routine returns a pointer to a block 2127** of memory at least N bytes in length, where N is the parameter. 2128** ^If sqlite3_malloc() is unable to obtain sufficient free 2129** memory, it returns a NULL pointer. ^If the parameter N to 2130** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 2131** a NULL pointer. 2132** 2133** ^Calling sqlite3_free() with a pointer previously returned 2134** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 2135** that it might be reused. ^The sqlite3_free() routine is 2136** a no-op if is called with a NULL pointer. Passing a NULL pointer 2137** to sqlite3_free() is harmless. After being freed, memory 2138** should neither be read nor written. Even reading previously freed 2139** memory might result in a segmentation fault or other severe error. 2140** Memory corruption, a segmentation fault, or other severe error 2141** might result if sqlite3_free() is called with a non-NULL pointer that 2142** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 2143** 2144** ^(The sqlite3_realloc() interface attempts to resize a 2145** prior memory allocation to be at least N bytes, where N is the 2146** second parameter. The memory allocation to be resized is the first 2147** parameter.)^ ^ If the first parameter to sqlite3_realloc() 2148** is a NULL pointer then its behavior is identical to calling 2149** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 2150** ^If the second parameter to sqlite3_realloc() is zero or 2151** negative then the behavior is exactly the same as calling 2152** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 2153** ^sqlite3_realloc() returns a pointer to a memory allocation 2154** of at least N bytes in size or NULL if sufficient memory is unavailable. 2155** ^If M is the size of the prior allocation, then min(N,M) bytes 2156** of the prior allocation are copied into the beginning of buffer returned 2157** by sqlite3_realloc() and the prior allocation is freed. 2158** ^If sqlite3_realloc() returns NULL, then the prior allocation 2159** is not freed. 2160** 2161** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 2162** is always aligned to at least an 8 byte boundary, or to a 2163** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time 2164** option is used. 2165** 2166** In SQLite version 3.5.0 and 3.5.1, it was possible to define 2167** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 2168** implementation of these routines to be omitted. That capability 2169** is no longer provided. Only built-in memory allocators can be used. 2170** 2171** The Windows OS interface layer calls 2172** the system malloc() and free() directly when converting 2173** filenames between the UTF-8 encoding used by SQLite 2174** and whatever filename encoding is used by the particular Windows 2175** installation. Memory allocation errors are detected, but 2176** they are reported back as [SQLITE_CANTOPEN] or 2177** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 2178** 2179** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 2180** must be either NULL or else pointers obtained from a prior 2181** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 2182** not yet been released. 2183** 2184** The application must not read or write any part of 2185** a block of memory after it has been released using 2186** [sqlite3_free()] or [sqlite3_realloc()]. 2187*/ 2188SQLITE_API void *sqlite3_malloc(int); 2189SQLITE_API void *sqlite3_realloc(void*, int); 2190SQLITE_API void sqlite3_free(void*); 2191 2192/* 2193** CAPI3REF: Memory Allocator Statistics 2194** 2195** SQLite provides these two interfaces for reporting on the status 2196** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 2197** routines, which form the built-in memory allocation subsystem. 2198** 2199** ^The [sqlite3_memory_used()] routine returns the number of bytes 2200** of memory currently outstanding (malloced but not freed). 2201** ^The [sqlite3_memory_highwater()] routine returns the maximum 2202** value of [sqlite3_memory_used()] since the high-water mark 2203** was last reset. ^The values returned by [sqlite3_memory_used()] and 2204** [sqlite3_memory_highwater()] include any overhead 2205** added by SQLite in its implementation of [sqlite3_malloc()], 2206** but not overhead added by the any underlying system library 2207** routines that [sqlite3_malloc()] may call. 2208** 2209** ^The memory high-water mark is reset to the current value of 2210** [sqlite3_memory_used()] if and only if the parameter to 2211** [sqlite3_memory_highwater()] is true. ^The value returned 2212** by [sqlite3_memory_highwater(1)] is the high-water mark 2213** prior to the reset. 2214*/ 2215SQLITE_API sqlite3_int64 sqlite3_memory_used(void); 2216SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 2217 2218/* 2219** CAPI3REF: Pseudo-Random Number Generator 2220** 2221** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 2222** select random [ROWID | ROWIDs] when inserting new records into a table that 2223** already uses the largest possible [ROWID]. The PRNG is also used for 2224** the build-in random() and randomblob() SQL functions. This interface allows 2225** applications to access the same PRNG for other purposes. 2226** 2227** ^A call to this routine stores N bytes of randomness into buffer P. 2228** 2229** ^The first time this routine is invoked (either internally or by 2230** the application) the PRNG is seeded using randomness obtained 2231** from the xRandomness method of the default [sqlite3_vfs] object. 2232** ^On all subsequent invocations, the pseudo-randomness is generated 2233** internally and without recourse to the [sqlite3_vfs] xRandomness 2234** method. 2235*/ 2236SQLITE_API void sqlite3_randomness(int N, void *P); 2237 2238/* 2239** CAPI3REF: Compile-Time Authorization Callbacks 2240** 2241** ^This routine registers an authorizer callback with a particular 2242** [database connection], supplied in the first argument. 2243** ^The authorizer callback is invoked as SQL statements are being compiled 2244** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 2245** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 2246** points during the compilation process, as logic is being created 2247** to perform various actions, the authorizer callback is invoked to 2248** see if those actions are allowed. ^The authorizer callback should 2249** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 2250** specific action but allow the SQL statement to continue to be 2251** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 2252** rejected with an error. ^If the authorizer callback returns 2253** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 2254** then the [sqlite3_prepare_v2()] or equivalent call that triggered 2255** the authorizer will fail with an error message. 2256** 2257** When the callback returns [SQLITE_OK], that means the operation 2258** requested is ok. ^When the callback returns [SQLITE_DENY], the 2259** [sqlite3_prepare_v2()] or equivalent call that triggered the 2260** authorizer will fail with an error message explaining that 2261** access is denied. 2262** 2263** ^The first parameter to the authorizer callback is a copy of the third 2264** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 2265** to the callback is an integer [SQLITE_COPY | action code] that specifies 2266** the particular action to be authorized. ^The third through sixth parameters 2267** to the callback are zero-terminated strings that contain additional 2268** details about the action to be authorized. 2269** 2270** ^If the action code is [SQLITE_READ] 2271** and the callback returns [SQLITE_IGNORE] then the 2272** [prepared statement] statement is constructed to substitute 2273** a NULL value in place of the table column that would have 2274** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 2275** return can be used to deny an untrusted user access to individual 2276** columns of a table. 2277** ^If the action code is [SQLITE_DELETE] and the callback returns 2278** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 2279** [truncate optimization] is disabled and all rows are deleted individually. 2280** 2281** An authorizer is used when [sqlite3_prepare | preparing] 2282** SQL statements from an untrusted source, to ensure that the SQL statements 2283** do not try to access data they are not allowed to see, or that they do not 2284** try to execute malicious statements that damage the database. For 2285** example, an application may allow a user to enter arbitrary 2286** SQL queries for evaluation by a database. But the application does 2287** not want the user to be able to make arbitrary changes to the 2288** database. An authorizer could then be put in place while the 2289** user-entered SQL is being [sqlite3_prepare | prepared] that 2290** disallows everything except [SELECT] statements. 2291** 2292** Applications that need to process SQL from untrusted sources 2293** might also consider lowering resource limits using [sqlite3_limit()] 2294** and limiting database size using the [max_page_count] [PRAGMA] 2295** in addition to using an authorizer. 2296** 2297** ^(Only a single authorizer can be in place on a database connection 2298** at a time. Each call to sqlite3_set_authorizer overrides the 2299** previous call.)^ ^Disable the authorizer by installing a NULL callback. 2300** The authorizer is disabled by default. 2301** 2302** The authorizer callback must not do anything that will modify 2303** the database connection that invoked the authorizer callback. 2304** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2305** database connections for the meaning of "modify" in this paragraph. 2306** 2307** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 2308** statement might be re-prepared during [sqlite3_step()] due to a 2309** schema change. Hence, the application should ensure that the 2310** correct authorizer callback remains in place during the [sqlite3_step()]. 2311** 2312** ^Note that the authorizer callback is invoked only during 2313** [sqlite3_prepare()] or its variants. Authorization is not 2314** performed during statement evaluation in [sqlite3_step()], unless 2315** as stated in the previous paragraph, sqlite3_step() invokes 2316** sqlite3_prepare_v2() to reprepare a statement after a schema change. 2317*/ 2318SQLITE_API int sqlite3_set_authorizer( 2319 sqlite3*, 2320 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 2321 void *pUserData 2322); 2323 2324/* 2325** CAPI3REF: Authorizer Return Codes 2326** 2327** The [sqlite3_set_authorizer | authorizer callback function] must 2328** return either [SQLITE_OK] or one of these two constants in order 2329** to signal SQLite whether or not the action is permitted. See the 2330** [sqlite3_set_authorizer | authorizer documentation] for additional 2331** information. 2332** 2333** Note that SQLITE_IGNORE is also used as a [SQLITE_ROLLBACK | return code] 2334** from the [sqlite3_vtab_on_conflict()] interface. 2335*/ 2336#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 2337#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 2338 2339/* 2340** CAPI3REF: Authorizer Action Codes 2341** 2342** The [sqlite3_set_authorizer()] interface registers a callback function 2343** that is invoked to authorize certain SQL statement actions. The 2344** second parameter to the callback is an integer code that specifies 2345** what action is being authorized. These are the integer action codes that 2346** the authorizer callback may be passed. 2347** 2348** These action code values signify what kind of operation is to be 2349** authorized. The 3rd and 4th parameters to the authorization 2350** callback function will be parameters or NULL depending on which of these 2351** codes is used as the second parameter. ^(The 5th parameter to the 2352** authorizer callback is the name of the database ("main", "temp", 2353** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 2354** is the name of the inner-most trigger or view that is responsible for 2355** the access attempt or NULL if this access attempt is directly from 2356** top-level SQL code. 2357*/ 2358/******************************************* 3rd ************ 4th ***********/ 2359#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2360#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2361#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2362#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2363#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2364#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2365#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2366#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2367#define SQLITE_DELETE 9 /* Table Name NULL */ 2368#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2369#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2370#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2371#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2372#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2373#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2374#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2375#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2376#define SQLITE_INSERT 18 /* Table Name NULL */ 2377#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2378#define SQLITE_READ 20 /* Table Name Column Name */ 2379#define SQLITE_SELECT 21 /* NULL NULL */ 2380#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2381#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2382#define SQLITE_ATTACH 24 /* Filename NULL */ 2383#define SQLITE_DETACH 25 /* Database Name NULL */ 2384#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2385#define SQLITE_REINDEX 27 /* Index Name NULL */ 2386#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2387#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2388#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2389#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2390#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2391#define SQLITE_COPY 0 /* No longer used */ 2392 2393/* 2394** CAPI3REF: Tracing And Profiling Functions 2395** 2396** These routines register callback functions that can be used for 2397** tracing and profiling the execution of SQL statements. 2398** 2399** ^The callback function registered by sqlite3_trace() is invoked at 2400** various times when an SQL statement is being run by [sqlite3_step()]. 2401** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2402** SQL statement text as the statement first begins executing. 2403** ^(Additional sqlite3_trace() callbacks might occur 2404** as each triggered subprogram is entered. The callbacks for triggers 2405** contain a UTF-8 SQL comment that identifies the trigger.)^ 2406** 2407** ^The callback function registered by sqlite3_profile() is invoked 2408** as each SQL statement finishes. ^The profile callback contains 2409** the original statement text and an estimate of wall-clock time 2410** of how long that statement took to run. ^The profile callback 2411** time is in units of nanoseconds, however the current implementation 2412** is only capable of millisecond resolution so the six least significant 2413** digits in the time are meaningless. Future versions of SQLite 2414** might provide greater resolution on the profiler callback. The 2415** sqlite3_profile() function is considered experimental and is 2416** subject to change in future versions of SQLite. 2417*/ 2418SQLITE_API void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2419SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2420 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2421 2422/* 2423** CAPI3REF: Query Progress Callbacks 2424** 2425** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback 2426** function X to be invoked periodically during long running calls to 2427** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for 2428** database connection D. An example use for this 2429** interface is to keep a GUI updated during a large query. 2430** 2431** ^The parameter P is passed through as the only parameter to the 2432** callback function X. ^The parameter N is the number of 2433** [virtual machine instructions] that are evaluated between successive 2434** invocations of the callback X. 2435** 2436** ^Only a single progress handler may be defined at one time per 2437** [database connection]; setting a new progress handler cancels the 2438** old one. ^Setting parameter X to NULL disables the progress handler. 2439** ^The progress handler is also disabled by setting N to a value less 2440** than 1. 2441** 2442** ^If the progress callback returns non-zero, the operation is 2443** interrupted. This feature can be used to implement a 2444** "Cancel" button on a GUI progress dialog box. 2445** 2446** The progress handler callback must not do anything that will modify 2447** the database connection that invoked the progress handler. 2448** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2449** database connections for the meaning of "modify" in this paragraph. 2450** 2451*/ 2452SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2453 2454/* 2455** CAPI3REF: Opening A New Database Connection 2456** 2457** ^These routines open an SQLite database file as specified by the 2458** filename argument. ^The filename argument is interpreted as UTF-8 for 2459** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2460** order for sqlite3_open16(). ^(A [database connection] handle is usually 2461** returned in *ppDb, even if an error occurs. The only exception is that 2462** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2463** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2464** object.)^ ^(If the database is opened (and/or created) successfully, then 2465** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2466** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2467** an English language description of the error following a failure of any 2468** of the sqlite3_open() routines. 2469** 2470** ^The default encoding for the database will be UTF-8 if 2471** sqlite3_open() or sqlite3_open_v2() is called and 2472** UTF-16 in the native byte order if sqlite3_open16() is used. 2473** 2474** Whether or not an error occurs when it is opened, resources 2475** associated with the [database connection] handle should be released by 2476** passing it to [sqlite3_close()] when it is no longer required. 2477** 2478** The sqlite3_open_v2() interface works like sqlite3_open() 2479** except that it accepts two additional parameters for additional control 2480** over the new database connection. ^(The flags parameter to 2481** sqlite3_open_v2() can take one of 2482** the following three values, optionally combined with the 2483** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2484** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^ 2485** 2486** <dl> 2487** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2488** <dd>The database is opened in read-only mode. If the database does not 2489** already exist, an error is returned.</dd>)^ 2490** 2491** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2492** <dd>The database is opened for reading and writing if possible, or reading 2493** only if the file is write protected by the operating system. In either 2494** case the database must already exist, otherwise an error is returned.</dd>)^ 2495** 2496** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2497** <dd>The database is opened for reading and writing, and is created if 2498** it does not already exist. This is the behavior that is always used for 2499** sqlite3_open() and sqlite3_open16().</dd>)^ 2500** </dl> 2501** 2502** If the 3rd parameter to sqlite3_open_v2() is not one of the 2503** combinations shown above optionally combined with other 2504** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits] 2505** then the behavior is undefined. 2506** 2507** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2508** opens in the multi-thread [threading mode] as long as the single-thread 2509** mode has not been set at compile-time or start-time. ^If the 2510** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2511** in the serialized [threading mode] unless single-thread was 2512** previously selected at compile-time or start-time. 2513** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2514** eligible to use [shared cache mode], regardless of whether or not shared 2515** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2516** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2517** participate in [shared cache mode] even if it is enabled. 2518** 2519** ^The fourth parameter to sqlite3_open_v2() is the name of the 2520** [sqlite3_vfs] object that defines the operating system interface that 2521** the new database connection should use. ^If the fourth parameter is 2522** a NULL pointer then the default [sqlite3_vfs] object is used. 2523** 2524** ^If the filename is ":memory:", then a private, temporary in-memory database 2525** is created for the connection. ^This in-memory database will vanish when 2526** the database connection is closed. Future versions of SQLite might 2527** make use of additional special filenames that begin with the ":" character. 2528** It is recommended that when a database filename actually does begin with 2529** a ":" character you should prefix the filename with a pathname such as 2530** "./" to avoid ambiguity. 2531** 2532** ^If the filename is an empty string, then a private, temporary 2533** on-disk database will be created. ^This private database will be 2534** automatically deleted as soon as the database connection is closed. 2535** 2536** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3> 2537** 2538** ^If [URI filename] interpretation is enabled, and the filename argument 2539** begins with "file:", then the filename is interpreted as a URI. ^URI 2540** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is 2541** set in the fourth argument to sqlite3_open_v2(), or if it has 2542** been enabled globally using the [SQLITE_CONFIG_URI] option with the 2543** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option. 2544** As of SQLite version 3.7.7, URI filename interpretation is turned off 2545** by default, but future releases of SQLite might enable URI filename 2546** interpretation by default. See "[URI filenames]" for additional 2547** information. 2548** 2549** URI filenames are parsed according to RFC 3986. ^If the URI contains an 2550** authority, then it must be either an empty string or the string 2551** "localhost". ^If the authority is not an empty string or "localhost", an 2552** error is returned to the caller. ^The fragment component of a URI, if 2553** present, is ignored. 2554** 2555** ^SQLite uses the path component of the URI as the name of the disk file 2556** which contains the database. ^If the path begins with a '/' character, 2557** then it is interpreted as an absolute path. ^If the path does not begin 2558** with a '/' (meaning that the authority section is omitted from the URI) 2559** then the path is interpreted as a relative path. 2560** ^On windows, the first component of an absolute path 2561** is a drive specification (e.g. "C:"). 2562** 2563** [[core URI query parameters]] 2564** The query component of a URI may contain parameters that are interpreted 2565** either by SQLite itself, or by a [VFS | custom VFS implementation]. 2566** SQLite interprets the following three query parameters: 2567** 2568** <ul> 2569** <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of 2570** a VFS object that provides the operating system interface that should 2571** be used to access the database file on disk. ^If this option is set to 2572** an empty string the default VFS object is used. ^Specifying an unknown 2573** VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is 2574** present, then the VFS specified by the option takes precedence over 2575** the value passed as the fourth parameter to sqlite3_open_v2(). 2576** 2577** <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw" or 2578** "rwc". Attempting to set it to any other value is an error)^. 2579** ^If "ro" is specified, then the database is opened for read-only 2580** access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 2581** third argument to sqlite3_prepare_v2(). ^If the mode option is set to 2582** "rw", then the database is opened for read-write (but not create) 2583** access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 2584** been set. ^Value "rwc" is equivalent to setting both 2585** SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE. ^If sqlite3_open_v2() is 2586** used, it is an error to specify a value for the mode parameter that is 2587** less restrictive than that specified by the flags passed as the third 2588** parameter. 2589** 2590** <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or 2591** "private". ^Setting it to "shared" is equivalent to setting the 2592** SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to 2593** sqlite3_open_v2(). ^Setting the cache parameter to "private" is 2594** equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit. 2595** ^If sqlite3_open_v2() is used and the "cache" parameter is present in 2596** a URI filename, its value overrides any behaviour requested by setting 2597** SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag. 2598** </ul> 2599** 2600** ^Specifying an unknown parameter in the query component of a URI is not an 2601** error. Future versions of SQLite might understand additional query 2602** parameters. See "[query parameters with special meaning to SQLite]" for 2603** additional information. 2604** 2605** [[URI filename examples]] <h3>URI filename examples</h3> 2606** 2607** <table border="1" align=center cellpadding=5> 2608** <tr><th> URI filenames <th> Results 2609** <tr><td> file:data.db <td> 2610** Open the file "data.db" in the current directory. 2611** <tr><td> file:/home/fred/data.db<br> 2612** file:///home/fred/data.db <br> 2613** file://localhost/home/fred/data.db <br> <td> 2614** Open the database file "/home/fred/data.db". 2615** <tr><td> file://darkstar/home/fred/data.db <td> 2616** An error. "darkstar" is not a recognized authority. 2617** <tr><td style="white-space:nowrap"> 2618** file:///C:/Documents%20and%20Settings/fred/Desktop/data.db 2619** <td> Windows only: Open the file "data.db" on fred's desktop on drive 2620** C:. Note that the %20 escaping in this example is not strictly 2621** necessary - space characters can be used literally 2622** in URI filenames. 2623** <tr><td> file:data.db?mode=ro&cache=private <td> 2624** Open file "data.db" in the current directory for read-only access. 2625** Regardless of whether or not shared-cache mode is enabled by 2626** default, use a private cache. 2627** <tr><td> file:/home/fred/data.db?vfs=unix-nolock <td> 2628** Open file "/home/fred/data.db". Use the special VFS "unix-nolock". 2629** <tr><td> file:data.db?mode=readonly <td> 2630** An error. "readonly" is not a valid option for the "mode" parameter. 2631** </table> 2632** 2633** ^URI hexadecimal escape sequences (%HH) are supported within the path and 2634** query components of a URI. A hexadecimal escape sequence consists of a 2635** percent sign - "%" - followed by exactly two hexadecimal digits 2636** specifying an octet value. ^Before the path or query components of a 2637** URI filename are interpreted, they are encoded using UTF-8 and all 2638** hexadecimal escape sequences replaced by a single byte containing the 2639** corresponding octet. If this process generates an invalid UTF-8 encoding, 2640** the results are undefined. 2641** 2642** <b>Note to Windows users:</b> The encoding used for the filename argument 2643** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2644** codepage is currently defined. Filenames containing international 2645** characters must be converted to UTF-8 prior to passing them into 2646** sqlite3_open() or sqlite3_open_v2(). 2647*/ 2648SQLITE_API int sqlite3_open( 2649 const char *filename, /* Database filename (UTF-8) */ 2650 sqlite3 **ppDb /* OUT: SQLite db handle */ 2651); 2652SQLITE_API int sqlite3_open16( 2653 const void *filename, /* Database filename (UTF-16) */ 2654 sqlite3 **ppDb /* OUT: SQLite db handle */ 2655); 2656SQLITE_API int sqlite3_open_v2( 2657 const char *filename, /* Database filename (UTF-8) */ 2658 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2659 int flags, /* Flags */ 2660 const char *zVfs /* Name of VFS module to use */ 2661); 2662 2663/* 2664** CAPI3REF: Obtain Values For URI Parameters 2665** 2666** These are utility routines, useful to VFS implementations, that check 2667** to see if a database file was a URI that contained a specific query 2668** parameter, and if so obtains the value of that query parameter. 2669** 2670** If F is the database filename pointer passed into the xOpen() method of 2671** a VFS implementation when the flags parameter to xOpen() has one or 2672** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and 2673** P is the name of the query parameter, then 2674** sqlite3_uri_parameter(F,P) returns the value of the P 2675** parameter if it exists or a NULL pointer if P does not appear as a 2676** query parameter on F. If P is a query parameter of F 2677** has no explicit value, then sqlite3_uri_parameter(F,P) returns 2678** a pointer to an empty string. 2679** 2680** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean 2681** parameter and returns true (1) or false (0) according to the value 2682** of P. The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the 2683** value of query parameter P is one of "yes", "true", or "on" in any 2684** case or if the value begins with a non-zero number. The 2685** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of 2686** query parameter P is one of "no", "false", or "off" in any case or 2687** if the value begins with a numeric zero. If P is not a query 2688** parameter on F or if the value of P is does not match any of the 2689** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0). 2690** 2691** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a 2692** 64-bit signed integer and returns that integer, or D if P does not 2693** exist. If the value of P is something other than an integer, then 2694** zero is returned. 2695** 2696** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and 2697** sqlite3_uri_boolean(F,P,B) returns B. If F is not a NULL pointer and 2698** is not a database file pathname pointer that SQLite passed into the xOpen 2699** VFS method, then the behavior of this routine is undefined and probably 2700** undesirable. 2701*/ 2702SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam); 2703SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault); 2704SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64); 2705 2706 2707/* 2708** CAPI3REF: Error Codes And Messages 2709** 2710** ^The sqlite3_errcode() interface returns the numeric [result code] or 2711** [extended result code] for the most recent failed sqlite3_* API call 2712** associated with a [database connection]. If a prior API call failed 2713** but the most recent API call succeeded, the return value from 2714** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2715** interface is the same except that it always returns the 2716** [extended result code] even when extended result codes are 2717** disabled. 2718** 2719** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2720** text that describes the error, as either UTF-8 or UTF-16 respectively. 2721** ^(Memory to hold the error message string is managed internally. 2722** The application does not need to worry about freeing the result. 2723** However, the error string might be overwritten or deallocated by 2724** subsequent calls to other SQLite interface functions.)^ 2725** 2726** When the serialized [threading mode] is in use, it might be the 2727** case that a second error occurs on a separate thread in between 2728** the time of the first error and the call to these interfaces. 2729** When that happens, the second error will be reported since these 2730** interfaces always report the most recent result. To avoid 2731** this, each thread can obtain exclusive use of the [database connection] D 2732** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2733** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2734** all calls to the interfaces listed here are completed. 2735** 2736** If an interface fails with SQLITE_MISUSE, that means the interface 2737** was invoked incorrectly by the application. In that case, the 2738** error code and message may or may not be set. 2739*/ 2740SQLITE_API int sqlite3_errcode(sqlite3 *db); 2741SQLITE_API int sqlite3_extended_errcode(sqlite3 *db); 2742SQLITE_API const char *sqlite3_errmsg(sqlite3*); 2743SQLITE_API const void *sqlite3_errmsg16(sqlite3*); 2744 2745/* 2746** CAPI3REF: SQL Statement Object 2747** KEYWORDS: {prepared statement} {prepared statements} 2748** 2749** An instance of this object represents a single SQL statement. 2750** This object is variously known as a "prepared statement" or a 2751** "compiled SQL statement" or simply as a "statement". 2752** 2753** The life of a statement object goes something like this: 2754** 2755** <ol> 2756** <li> Create the object using [sqlite3_prepare_v2()] or a related 2757** function. 2758** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2759** interfaces. 2760** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2761** <li> Reset the statement using [sqlite3_reset()] then go back 2762** to step 2. Do this zero or more times. 2763** <li> Destroy the object using [sqlite3_finalize()]. 2764** </ol> 2765** 2766** Refer to documentation on individual methods above for additional 2767** information. 2768*/ 2769typedef struct sqlite3_stmt sqlite3_stmt; 2770 2771/* 2772** CAPI3REF: Run-time Limits 2773** 2774** ^(This interface allows the size of various constructs to be limited 2775** on a connection by connection basis. The first parameter is the 2776** [database connection] whose limit is to be set or queried. The 2777** second parameter is one of the [limit categories] that define a 2778** class of constructs to be size limited. The third parameter is the 2779** new limit for that construct.)^ 2780** 2781** ^If the new limit is a negative number, the limit is unchanged. 2782** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 2783** [limits | hard upper bound] 2784** set at compile-time by a C preprocessor macro called 2785** [limits | SQLITE_MAX_<i>NAME</i>]. 2786** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2787** ^Attempts to increase a limit above its hard upper bound are 2788** silently truncated to the hard upper bound. 2789** 2790** ^Regardless of whether or not the limit was changed, the 2791** [sqlite3_limit()] interface returns the prior value of the limit. 2792** ^Hence, to find the current value of a limit without changing it, 2793** simply invoke this interface with the third parameter set to -1. 2794** 2795** Run-time limits are intended for use in applications that manage 2796** both their own internal database and also databases that are controlled 2797** by untrusted external sources. An example application might be a 2798** web browser that has its own databases for storing history and 2799** separate databases controlled by JavaScript applications downloaded 2800** off the Internet. The internal databases can be given the 2801** large, default limits. Databases managed by external sources can 2802** be given much smaller limits designed to prevent a denial of service 2803** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2804** interface to further control untrusted SQL. The size of the database 2805** created by an untrusted script can be contained using the 2806** [max_page_count] [PRAGMA]. 2807** 2808** New run-time limit categories may be added in future releases. 2809*/ 2810SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal); 2811 2812/* 2813** CAPI3REF: Run-Time Limit Categories 2814** KEYWORDS: {limit category} {*limit categories} 2815** 2816** These constants define various performance limits 2817** that can be lowered at run-time using [sqlite3_limit()]. 2818** The synopsis of the meanings of the various limits is shown below. 2819** Additional information is available at [limits | Limits in SQLite]. 2820** 2821** <dl> 2822** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2823** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^ 2824** 2825** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2826** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2827** 2828** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2829** <dd>The maximum number of columns in a table definition or in the 2830** result set of a [SELECT] or the maximum number of columns in an index 2831** or in an ORDER BY or GROUP BY clause.</dd>)^ 2832** 2833** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2834** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2835** 2836** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2837** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2838** 2839** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2840** <dd>The maximum number of instructions in a virtual machine program 2841** used to implement an SQL statement. This limit is not currently 2842** enforced, though that might be added in some future release of 2843** SQLite.</dd>)^ 2844** 2845** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2846** <dd>The maximum number of arguments on a function.</dd>)^ 2847** 2848** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2849** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2850** 2851** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]] 2852** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2853** <dd>The maximum length of the pattern argument to the [LIKE] or 2854** [GLOB] operators.</dd>)^ 2855** 2856** [[SQLITE_LIMIT_VARIABLE_NUMBER]] 2857** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2858** <dd>The maximum index number of any [parameter] in an SQL statement.)^ 2859** 2860** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2861** <dd>The maximum depth of recursion for triggers.</dd>)^ 2862** </dl> 2863*/ 2864#define SQLITE_LIMIT_LENGTH 0 2865#define SQLITE_LIMIT_SQL_LENGTH 1 2866#define SQLITE_LIMIT_COLUMN 2 2867#define SQLITE_LIMIT_EXPR_DEPTH 3 2868#define SQLITE_LIMIT_COMPOUND_SELECT 4 2869#define SQLITE_LIMIT_VDBE_OP 5 2870#define SQLITE_LIMIT_FUNCTION_ARG 6 2871#define SQLITE_LIMIT_ATTACHED 7 2872#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2873#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2874#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2875 2876/* 2877** CAPI3REF: Compiling An SQL Statement 2878** KEYWORDS: {SQL statement compiler} 2879** 2880** To execute an SQL query, it must first be compiled into a byte-code 2881** program using one of these routines. 2882** 2883** The first argument, "db", is a [database connection] obtained from a 2884** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2885** [sqlite3_open16()]. The database connection must not have been closed. 2886** 2887** The second argument, "zSql", is the statement to be compiled, encoded 2888** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2889** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2890** use UTF-16. 2891** 2892** ^If the nByte argument is less than zero, then zSql is read up to the 2893** first zero terminator. ^If nByte is non-negative, then it is the maximum 2894** number of bytes read from zSql. ^When nByte is non-negative, the 2895** zSql string ends at either the first '\000' or '\u0000' character or 2896** the nByte-th byte, whichever comes first. If the caller knows 2897** that the supplied string is nul-terminated, then there is a small 2898** performance advantage to be gained by passing an nByte parameter that 2899** is equal to the number of bytes in the input string <i>including</i> 2900** the nul-terminator bytes as this saves SQLite from having to 2901** make a copy of the input string. 2902** 2903** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2904** past the end of the first SQL statement in zSql. These routines only 2905** compile the first statement in zSql, so *pzTail is left pointing to 2906** what remains uncompiled. 2907** 2908** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2909** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2910** to NULL. ^If the input text contains no SQL (if the input is an empty 2911** string or a comment) then *ppStmt is set to NULL. 2912** The calling procedure is responsible for deleting the compiled 2913** SQL statement using [sqlite3_finalize()] after it has finished with it. 2914** ppStmt may not be NULL. 2915** 2916** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2917** otherwise an [error code] is returned. 2918** 2919** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2920** recommended for all new programs. The two older interfaces are retained 2921** for backwards compatibility, but their use is discouraged. 2922** ^In the "v2" interfaces, the prepared statement 2923** that is returned (the [sqlite3_stmt] object) contains a copy of the 2924** original SQL text. This causes the [sqlite3_step()] interface to 2925** behave differently in three ways: 2926** 2927** <ol> 2928** <li> 2929** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2930** always used to do, [sqlite3_step()] will automatically recompile the SQL 2931** statement and try to run it again. 2932** </li> 2933** 2934** <li> 2935** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2936** [error codes] or [extended error codes]. ^The legacy behavior was that 2937** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2938** and the application would have to make a second call to [sqlite3_reset()] 2939** in order to find the underlying cause of the problem. With the "v2" prepare 2940** interfaces, the underlying reason for the error is returned immediately. 2941** </li> 2942** 2943** <li> 2944** ^If the specific value bound to [parameter | host parameter] in the 2945** WHERE clause might influence the choice of query plan for a statement, 2946** then the statement will be automatically recompiled, as if there had been 2947** a schema change, on the first [sqlite3_step()] call following any change 2948** to the [sqlite3_bind_text | bindings] of that [parameter]. 2949** ^The specific value of WHERE-clause [parameter] might influence the 2950** choice of query plan if the parameter is the left-hand side of a [LIKE] 2951** or [GLOB] operator or if the parameter is compared to an indexed column 2952** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled. 2953** the 2954** </li> 2955** </ol> 2956*/ 2957SQLITE_API int sqlite3_prepare( 2958 sqlite3 *db, /* Database handle */ 2959 const char *zSql, /* SQL statement, UTF-8 encoded */ 2960 int nByte, /* Maximum length of zSql in bytes. */ 2961 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2962 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2963); 2964SQLITE_API int sqlite3_prepare_v2( 2965 sqlite3 *db, /* Database handle */ 2966 const char *zSql, /* SQL statement, UTF-8 encoded */ 2967 int nByte, /* Maximum length of zSql in bytes. */ 2968 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2969 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2970); 2971SQLITE_API int sqlite3_prepare16( 2972 sqlite3 *db, /* Database handle */ 2973 const void *zSql, /* SQL statement, UTF-16 encoded */ 2974 int nByte, /* Maximum length of zSql in bytes. */ 2975 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2976 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2977); 2978SQLITE_API int sqlite3_prepare16_v2( 2979 sqlite3 *db, /* Database handle */ 2980 const void *zSql, /* SQL statement, UTF-16 encoded */ 2981 int nByte, /* Maximum length of zSql in bytes. */ 2982 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2983 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2984); 2985 2986/* 2987** CAPI3REF: Retrieving Statement SQL 2988** 2989** ^This interface can be used to retrieve a saved copy of the original 2990** SQL text used to create a [prepared statement] if that statement was 2991** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2992*/ 2993SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt); 2994 2995/* 2996** CAPI3REF: Determine If An SQL Statement Writes The Database 2997** 2998** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if 2999** and only if the [prepared statement] X makes no direct changes to 3000** the content of the database file. 3001** 3002** Note that [application-defined SQL functions] or 3003** [virtual tables] might change the database indirectly as a side effect. 3004** ^(For example, if an application defines a function "eval()" that 3005** calls [sqlite3_exec()], then the following SQL statement would 3006** change the database file through side-effects: 3007** 3008** <blockquote><pre> 3009** SELECT eval('DELETE FROM t1') FROM t2; 3010** </pre></blockquote> 3011** 3012** But because the [SELECT] statement does not change the database file 3013** directly, sqlite3_stmt_readonly() would still return true.)^ 3014** 3015** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK], 3016** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true, 3017** since the statements themselves do not actually modify the database but 3018** rather they control the timing of when other statements modify the 3019** database. ^The [ATTACH] and [DETACH] statements also cause 3020** sqlite3_stmt_readonly() to return true since, while those statements 3021** change the configuration of a database connection, they do not make 3022** changes to the content of the database files on disk. 3023*/ 3024SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt); 3025 3026/* 3027** CAPI3REF: Determine If A Prepared Statement Has Been Reset 3028** 3029** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the 3030** [prepared statement] S has been stepped at least once using 3031** [sqlite3_step(S)] but has not run to completion and/or has not 3032** been reset using [sqlite3_reset(S)]. ^The sqlite3_stmt_busy(S) 3033** interface returns false if S is a NULL pointer. If S is not a 3034** NULL pointer and is not a pointer to a valid [prepared statement] 3035** object, then the behavior is undefined and probably undesirable. 3036** 3037** This interface can be used in combination [sqlite3_next_stmt()] 3038** to locate all prepared statements associated with a database 3039** connection that are in need of being reset. This can be used, 3040** for example, in diagnostic routines to search for prepared 3041** statements that are holding a transaction open. 3042*/ 3043SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*); 3044 3045/* 3046** CAPI3REF: Dynamically Typed Value Object 3047** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 3048** 3049** SQLite uses the sqlite3_value object to represent all values 3050** that can be stored in a database table. SQLite uses dynamic typing 3051** for the values it stores. ^Values stored in sqlite3_value objects 3052** can be integers, floating point values, strings, BLOBs, or NULL. 3053** 3054** An sqlite3_value object may be either "protected" or "unprotected". 3055** Some interfaces require a protected sqlite3_value. Other interfaces 3056** will accept either a protected or an unprotected sqlite3_value. 3057** Every interface that accepts sqlite3_value arguments specifies 3058** whether or not it requires a protected sqlite3_value. 3059** 3060** The terms "protected" and "unprotected" refer to whether or not 3061** a mutex is held. An internal mutex is held for a protected 3062** sqlite3_value object but no mutex is held for an unprotected 3063** sqlite3_value object. If SQLite is compiled to be single-threaded 3064** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 3065** or if SQLite is run in one of reduced mutex modes 3066** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 3067** then there is no distinction between protected and unprotected 3068** sqlite3_value objects and they can be used interchangeably. However, 3069** for maximum code portability it is recommended that applications 3070** still make the distinction between protected and unprotected 3071** sqlite3_value objects even when not strictly required. 3072** 3073** ^The sqlite3_value objects that are passed as parameters into the 3074** implementation of [application-defined SQL functions] are protected. 3075** ^The sqlite3_value object returned by 3076** [sqlite3_column_value()] is unprotected. 3077** Unprotected sqlite3_value objects may only be used with 3078** [sqlite3_result_value()] and [sqlite3_bind_value()]. 3079** The [sqlite3_value_blob | sqlite3_value_type()] family of 3080** interfaces require protected sqlite3_value objects. 3081*/ 3082typedef struct Mem sqlite3_value; 3083 3084/* 3085** CAPI3REF: SQL Function Context Object 3086** 3087** The context in which an SQL function executes is stored in an 3088** sqlite3_context object. ^A pointer to an sqlite3_context object 3089** is always first parameter to [application-defined SQL functions]. 3090** The application-defined SQL function implementation will pass this 3091** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 3092** [sqlite3_aggregate_context()], [sqlite3_user_data()], 3093** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 3094** and/or [sqlite3_set_auxdata()]. 3095*/ 3096typedef struct sqlite3_context sqlite3_context; 3097 3098/* 3099** CAPI3REF: Binding Values To Prepared Statements 3100** KEYWORDS: {host parameter} {host parameters} {host parameter name} 3101** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 3102** 3103** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 3104** literals may be replaced by a [parameter] that matches one of following 3105** templates: 3106** 3107** <ul> 3108** <li> ? 3109** <li> ?NNN 3110** <li> :VVV 3111** <li> @VVV 3112** <li> $VVV 3113** </ul> 3114** 3115** In the templates above, NNN represents an integer literal, 3116** and VVV represents an alphanumeric identifier.)^ ^The values of these 3117** parameters (also called "host parameter names" or "SQL parameters") 3118** can be set using the sqlite3_bind_*() routines defined here. 3119** 3120** ^The first argument to the sqlite3_bind_*() routines is always 3121** a pointer to the [sqlite3_stmt] object returned from 3122** [sqlite3_prepare_v2()] or its variants. 3123** 3124** ^The second argument is the index of the SQL parameter to be set. 3125** ^The leftmost SQL parameter has an index of 1. ^When the same named 3126** SQL parameter is used more than once, second and subsequent 3127** occurrences have the same index as the first occurrence. 3128** ^The index for named parameters can be looked up using the 3129** [sqlite3_bind_parameter_index()] API if desired. ^The index 3130** for "?NNN" parameters is the value of NNN. 3131** ^The NNN value must be between 1 and the [sqlite3_limit()] 3132** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 3133** 3134** ^The third argument is the value to bind to the parameter. 3135** 3136** ^(In those routines that have a fourth argument, its value is the 3137** number of bytes in the parameter. To be clear: the value is the 3138** number of <u>bytes</u> in the value, not the number of characters.)^ 3139** ^If the fourth parameter is negative, the length of the string is 3140** the number of bytes up to the first zero terminator. 3141** If a non-negative fourth parameter is provided to sqlite3_bind_text() 3142** or sqlite3_bind_text16() then that parameter must be the byte offset 3143** where the NUL terminator would occur assuming the string were NUL 3144** terminated. If any NUL characters occur at byte offsets less than 3145** the value of the fourth parameter then the resulting string value will 3146** contain embedded NULs. The result of expressions involving strings 3147** with embedded NULs is undefined. 3148** 3149** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 3150** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 3151** string after SQLite has finished with it. ^The destructor is called 3152** to dispose of the BLOB or string even if the call to sqlite3_bind_blob(), 3153** sqlite3_bind_text(), or sqlite3_bind_text16() fails. 3154** ^If the fifth argument is 3155** the special value [SQLITE_STATIC], then SQLite assumes that the 3156** information is in static, unmanaged space and does not need to be freed. 3157** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 3158** SQLite makes its own private copy of the data immediately, before 3159** the sqlite3_bind_*() routine returns. 3160** 3161** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 3162** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 3163** (just an integer to hold its size) while it is being processed. 3164** Zeroblobs are intended to serve as placeholders for BLOBs whose 3165** content is later written using 3166** [sqlite3_blob_open | incremental BLOB I/O] routines. 3167** ^A negative value for the zeroblob results in a zero-length BLOB. 3168** 3169** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 3170** for the [prepared statement] or with a prepared statement for which 3171** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 3172** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 3173** routine is passed a [prepared statement] that has been finalized, the 3174** result is undefined and probably harmful. 3175** 3176** ^Bindings are not cleared by the [sqlite3_reset()] routine. 3177** ^Unbound parameters are interpreted as NULL. 3178** 3179** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 3180** [error code] if anything goes wrong. 3181** ^[SQLITE_RANGE] is returned if the parameter 3182** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 3183** 3184** See also: [sqlite3_bind_parameter_count()], 3185** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 3186*/ 3187SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 3188SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double); 3189SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int); 3190SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 3191SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int); 3192SQLITE_API int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 3193SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 3194SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 3195SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 3196 3197/* 3198** CAPI3REF: Number Of SQL Parameters 3199** 3200** ^This routine can be used to find the number of [SQL parameters] 3201** in a [prepared statement]. SQL parameters are tokens of the 3202** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 3203** placeholders for values that are [sqlite3_bind_blob | bound] 3204** to the parameters at a later time. 3205** 3206** ^(This routine actually returns the index of the largest (rightmost) 3207** parameter. For all forms except ?NNN, this will correspond to the 3208** number of unique parameters. If parameters of the ?NNN form are used, 3209** there may be gaps in the list.)^ 3210** 3211** See also: [sqlite3_bind_blob|sqlite3_bind()], 3212** [sqlite3_bind_parameter_name()], and 3213** [sqlite3_bind_parameter_index()]. 3214*/ 3215SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*); 3216 3217/* 3218** CAPI3REF: Name Of A Host Parameter 3219** 3220** ^The sqlite3_bind_parameter_name(P,N) interface returns 3221** the name of the N-th [SQL parameter] in the [prepared statement] P. 3222** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 3223** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 3224** respectively. 3225** In other words, the initial ":" or "$" or "@" or "?" 3226** is included as part of the name.)^ 3227** ^Parameters of the form "?" without a following integer have no name 3228** and are referred to as "nameless" or "anonymous parameters". 3229** 3230** ^The first host parameter has an index of 1, not 0. 3231** 3232** ^If the value N is out of range or if the N-th parameter is 3233** nameless, then NULL is returned. ^The returned string is 3234** always in UTF-8 encoding even if the named parameter was 3235** originally specified as UTF-16 in [sqlite3_prepare16()] or 3236** [sqlite3_prepare16_v2()]. 3237** 3238** See also: [sqlite3_bind_blob|sqlite3_bind()], 3239** [sqlite3_bind_parameter_count()], and 3240** [sqlite3_bind_parameter_index()]. 3241*/ 3242SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 3243 3244/* 3245** CAPI3REF: Index Of A Parameter With A Given Name 3246** 3247** ^Return the index of an SQL parameter given its name. ^The 3248** index value returned is suitable for use as the second 3249** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 3250** is returned if no matching parameter is found. ^The parameter 3251** name must be given in UTF-8 even if the original statement 3252** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 3253** 3254** See also: [sqlite3_bind_blob|sqlite3_bind()], 3255** [sqlite3_bind_parameter_count()], and 3256** [sqlite3_bind_parameter_index()]. 3257*/ 3258SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 3259 3260/* 3261** CAPI3REF: Reset All Bindings On A Prepared Statement 3262** 3263** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 3264** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 3265** ^Use this routine to reset all host parameters to NULL. 3266*/ 3267SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*); 3268 3269/* 3270** CAPI3REF: Number Of Columns In A Result Set 3271** 3272** ^Return the number of columns in the result set returned by the 3273** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 3274** statement that does not return data (for example an [UPDATE]). 3275** 3276** See also: [sqlite3_data_count()] 3277*/ 3278SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt); 3279 3280/* 3281** CAPI3REF: Column Names In A Result Set 3282** 3283** ^These routines return the name assigned to a particular column 3284** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 3285** interface returns a pointer to a zero-terminated UTF-8 string 3286** and sqlite3_column_name16() returns a pointer to a zero-terminated 3287** UTF-16 string. ^The first parameter is the [prepared statement] 3288** that implements the [SELECT] statement. ^The second parameter is the 3289** column number. ^The leftmost column is number 0. 3290** 3291** ^The returned string pointer is valid until either the [prepared statement] 3292** is destroyed by [sqlite3_finalize()] or until the statement is automatically 3293** reprepared by the first call to [sqlite3_step()] for a particular run 3294** or until the next call to 3295** sqlite3_column_name() or sqlite3_column_name16() on the same column. 3296** 3297** ^If sqlite3_malloc() fails during the processing of either routine 3298** (for example during a conversion from UTF-8 to UTF-16) then a 3299** NULL pointer is returned. 3300** 3301** ^The name of a result column is the value of the "AS" clause for 3302** that column, if there is an AS clause. If there is no AS clause 3303** then the name of the column is unspecified and may change from 3304** one release of SQLite to the next. 3305*/ 3306SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N); 3307SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N); 3308 3309/* 3310** CAPI3REF: Source Of Data In A Query Result 3311** 3312** ^These routines provide a means to determine the database, table, and 3313** table column that is the origin of a particular result column in 3314** [SELECT] statement. 3315** ^The name of the database or table or column can be returned as 3316** either a UTF-8 or UTF-16 string. ^The _database_ routines return 3317** the database name, the _table_ routines return the table name, and 3318** the origin_ routines return the column name. 3319** ^The returned string is valid until the [prepared statement] is destroyed 3320** using [sqlite3_finalize()] or until the statement is automatically 3321** reprepared by the first call to [sqlite3_step()] for a particular run 3322** or until the same information is requested 3323** again in a different encoding. 3324** 3325** ^The names returned are the original un-aliased names of the 3326** database, table, and column. 3327** 3328** ^The first argument to these interfaces is a [prepared statement]. 3329** ^These functions return information about the Nth result column returned by 3330** the statement, where N is the second function argument. 3331** ^The left-most column is column 0 for these routines. 3332** 3333** ^If the Nth column returned by the statement is an expression or 3334** subquery and is not a column value, then all of these functions return 3335** NULL. ^These routine might also return NULL if a memory allocation error 3336** occurs. ^Otherwise, they return the name of the attached database, table, 3337** or column that query result column was extracted from. 3338** 3339** ^As with all other SQLite APIs, those whose names end with "16" return 3340** UTF-16 encoded strings and the other functions return UTF-8. 3341** 3342** ^These APIs are only available if the library was compiled with the 3343** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 3344** 3345** If two or more threads call one or more of these routines against the same 3346** prepared statement and column at the same time then the results are 3347** undefined. 3348** 3349** If two or more threads call one or more 3350** [sqlite3_column_database_name | column metadata interfaces] 3351** for the same [prepared statement] and result column 3352** at the same time then the results are undefined. 3353*/ 3354SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int); 3355SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 3356SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int); 3357SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 3358SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 3359SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 3360 3361/* 3362** CAPI3REF: Declared Datatype Of A Query Result 3363** 3364** ^(The first parameter is a [prepared statement]. 3365** If this statement is a [SELECT] statement and the Nth column of the 3366** returned result set of that [SELECT] is a table column (not an 3367** expression or subquery) then the declared type of the table 3368** column is returned.)^ ^If the Nth column of the result set is an 3369** expression or subquery, then a NULL pointer is returned. 3370** ^The returned string is always UTF-8 encoded. 3371** 3372** ^(For example, given the database schema: 3373** 3374** CREATE TABLE t1(c1 VARIANT); 3375** 3376** and the following statement to be compiled: 3377** 3378** SELECT c1 + 1, c1 FROM t1; 3379** 3380** this routine would return the string "VARIANT" for the second result 3381** column (i==1), and a NULL pointer for the first result column (i==0).)^ 3382** 3383** ^SQLite uses dynamic run-time typing. ^So just because a column 3384** is declared to contain a particular type does not mean that the 3385** data stored in that column is of the declared type. SQLite is 3386** strongly typed, but the typing is dynamic not static. ^Type 3387** is associated with individual values, not with the containers 3388** used to hold those values. 3389*/ 3390SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int); 3391SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 3392 3393/* 3394** CAPI3REF: Evaluate An SQL Statement 3395** 3396** After a [prepared statement] has been prepared using either 3397** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 3398** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 3399** must be called one or more times to evaluate the statement. 3400** 3401** The details of the behavior of the sqlite3_step() interface depend 3402** on whether the statement was prepared using the newer "v2" interface 3403** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 3404** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 3405** new "v2" interface is recommended for new applications but the legacy 3406** interface will continue to be supported. 3407** 3408** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 3409** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 3410** ^With the "v2" interface, any of the other [result codes] or 3411** [extended result codes] might be returned as well. 3412** 3413** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 3414** database locks it needs to do its job. ^If the statement is a [COMMIT] 3415** or occurs outside of an explicit transaction, then you can retry the 3416** statement. If the statement is not a [COMMIT] and occurs within an 3417** explicit transaction then you should rollback the transaction before 3418** continuing. 3419** 3420** ^[SQLITE_DONE] means that the statement has finished executing 3421** successfully. sqlite3_step() should not be called again on this virtual 3422** machine without first calling [sqlite3_reset()] to reset the virtual 3423** machine back to its initial state. 3424** 3425** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 3426** is returned each time a new row of data is ready for processing by the 3427** caller. The values may be accessed using the [column access functions]. 3428** sqlite3_step() is called again to retrieve the next row of data. 3429** 3430** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 3431** violation) has occurred. sqlite3_step() should not be called again on 3432** the VM. More information may be found by calling [sqlite3_errmsg()]. 3433** ^With the legacy interface, a more specific error code (for example, 3434** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 3435** can be obtained by calling [sqlite3_reset()] on the 3436** [prepared statement]. ^In the "v2" interface, 3437** the more specific error code is returned directly by sqlite3_step(). 3438** 3439** [SQLITE_MISUSE] means that the this routine was called inappropriately. 3440** Perhaps it was called on a [prepared statement] that has 3441** already been [sqlite3_finalize | finalized] or on one that had 3442** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 3443** be the case that the same database connection is being used by two or 3444** more threads at the same moment in time. 3445** 3446** For all versions of SQLite up to and including 3.6.23.1, a call to 3447** [sqlite3_reset()] was required after sqlite3_step() returned anything 3448** other than [SQLITE_ROW] before any subsequent invocation of 3449** sqlite3_step(). Failure to reset the prepared statement using 3450** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from 3451** sqlite3_step(). But after version 3.6.23.1, sqlite3_step() began 3452** calling [sqlite3_reset()] automatically in this circumstance rather 3453** than returning [SQLITE_MISUSE]. This is not considered a compatibility 3454** break because any application that ever receives an SQLITE_MISUSE error 3455** is broken by definition. The [SQLITE_OMIT_AUTORESET] compile-time option 3456** can be used to restore the legacy behavior. 3457** 3458** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 3459** API always returns a generic error code, [SQLITE_ERROR], following any 3460** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 3461** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 3462** specific [error codes] that better describes the error. 3463** We admit that this is a goofy design. The problem has been fixed 3464** with the "v2" interface. If you prepare all of your SQL statements 3465** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 3466** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 3467** then the more specific [error codes] are returned directly 3468** by sqlite3_step(). The use of the "v2" interface is recommended. 3469*/ 3470SQLITE_API int sqlite3_step(sqlite3_stmt*); 3471 3472/* 3473** CAPI3REF: Number of columns in a result set 3474** 3475** ^The sqlite3_data_count(P) interface returns the number of columns in the 3476** current row of the result set of [prepared statement] P. 3477** ^If prepared statement P does not have results ready to return 3478** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of 3479** interfaces) then sqlite3_data_count(P) returns 0. 3480** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer. 3481** ^The sqlite3_data_count(P) routine returns 0 if the previous call to 3482** [sqlite3_step](P) returned [SQLITE_DONE]. ^The sqlite3_data_count(P) 3483** will return non-zero if previous call to [sqlite3_step](P) returned 3484** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum] 3485** where it always returns zero since each step of that multi-step 3486** pragma returns 0 columns of data. 3487** 3488** See also: [sqlite3_column_count()] 3489*/ 3490SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt); 3491 3492/* 3493** CAPI3REF: Fundamental Datatypes 3494** KEYWORDS: SQLITE_TEXT 3495** 3496** ^(Every value in SQLite has one of five fundamental datatypes: 3497** 3498** <ul> 3499** <li> 64-bit signed integer 3500** <li> 64-bit IEEE floating point number 3501** <li> string 3502** <li> BLOB 3503** <li> NULL 3504** </ul>)^ 3505** 3506** These constants are codes for each of those types. 3507** 3508** Note that the SQLITE_TEXT constant was also used in SQLite version 2 3509** for a completely different meaning. Software that links against both 3510** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 3511** SQLITE_TEXT. 3512*/ 3513#define SQLITE_INTEGER 1 3514#define SQLITE_FLOAT 2 3515#define SQLITE_BLOB 4 3516#define SQLITE_NULL 5 3517#ifdef SQLITE_TEXT 3518# undef SQLITE_TEXT 3519#else 3520# define SQLITE_TEXT 3 3521#endif 3522#define SQLITE3_TEXT 3 3523 3524/* 3525** CAPI3REF: Result Values From A Query 3526** KEYWORDS: {column access functions} 3527** 3528** These routines form the "result set" interface. 3529** 3530** ^These routines return information about a single column of the current 3531** result row of a query. ^In every case the first argument is a pointer 3532** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 3533** that was returned from [sqlite3_prepare_v2()] or one of its variants) 3534** and the second argument is the index of the column for which information 3535** should be returned. ^The leftmost column of the result set has the index 0. 3536** ^The number of columns in the result can be determined using 3537** [sqlite3_column_count()]. 3538** 3539** If the SQL statement does not currently point to a valid row, or if the 3540** column index is out of range, the result is undefined. 3541** These routines may only be called when the most recent call to 3542** [sqlite3_step()] has returned [SQLITE_ROW] and neither 3543** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 3544** If any of these routines are called after [sqlite3_reset()] or 3545** [sqlite3_finalize()] or after [sqlite3_step()] has returned 3546** something other than [SQLITE_ROW], the results are undefined. 3547** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 3548** are called from a different thread while any of these routines 3549** are pending, then the results are undefined. 3550** 3551** ^The sqlite3_column_type() routine returns the 3552** [SQLITE_INTEGER | datatype code] for the initial data type 3553** of the result column. ^The returned value is one of [SQLITE_INTEGER], 3554** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 3555** returned by sqlite3_column_type() is only meaningful if no type 3556** conversions have occurred as described below. After a type conversion, 3557** the value returned by sqlite3_column_type() is undefined. Future 3558** versions of SQLite may change the behavior of sqlite3_column_type() 3559** following a type conversion. 3560** 3561** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 3562** routine returns the number of bytes in that BLOB or string. 3563** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 3564** the string to UTF-8 and then returns the number of bytes. 3565** ^If the result is a numeric value then sqlite3_column_bytes() uses 3566** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 3567** the number of bytes in that string. 3568** ^If the result is NULL, then sqlite3_column_bytes() returns zero. 3569** 3570** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16() 3571** routine returns the number of bytes in that BLOB or string. 3572** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts 3573** the string to UTF-16 and then returns the number of bytes. 3574** ^If the result is a numeric value then sqlite3_column_bytes16() uses 3575** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns 3576** the number of bytes in that string. 3577** ^If the result is NULL, then sqlite3_column_bytes16() returns zero. 3578** 3579** ^The values returned by [sqlite3_column_bytes()] and 3580** [sqlite3_column_bytes16()] do not include the zero terminators at the end 3581** of the string. ^For clarity: the values returned by 3582** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of 3583** bytes in the string, not the number of characters. 3584** 3585** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 3586** even empty strings, are always zero-terminated. ^The return 3587** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer. 3588** 3589** ^The object returned by [sqlite3_column_value()] is an 3590** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 3591** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 3592** If the [unprotected sqlite3_value] object returned by 3593** [sqlite3_column_value()] is used in any other way, including calls 3594** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 3595** or [sqlite3_value_bytes()], then the behavior is undefined. 3596** 3597** These routines attempt to convert the value where appropriate. ^For 3598** example, if the internal representation is FLOAT and a text result 3599** is requested, [sqlite3_snprintf()] is used internally to perform the 3600** conversion automatically. ^(The following table details the conversions 3601** that are applied: 3602** 3603** <blockquote> 3604** <table border="1"> 3605** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 3606** 3607** <tr><td> NULL <td> INTEGER <td> Result is 0 3608** <tr><td> NULL <td> FLOAT <td> Result is 0.0 3609** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 3610** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 3611** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 3612** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 3613** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 3614** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 3615** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 3616** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 3617** <tr><td> TEXT <td> INTEGER <td> Use atoi() 3618** <tr><td> TEXT <td> FLOAT <td> Use atof() 3619** <tr><td> TEXT <td> BLOB <td> No change 3620** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 3621** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 3622** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 3623** </table> 3624** </blockquote>)^ 3625** 3626** The table above makes reference to standard C library functions atoi() 3627** and atof(). SQLite does not really use these functions. It has its 3628** own equivalent internal routines. The atoi() and atof() names are 3629** used in the table for brevity and because they are familiar to most 3630** C programmers. 3631** 3632** Note that when type conversions occur, pointers returned by prior 3633** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3634** sqlite3_column_text16() may be invalidated. 3635** Type conversions and pointer invalidations might occur 3636** in the following cases: 3637** 3638** <ul> 3639** <li> The initial content is a BLOB and sqlite3_column_text() or 3640** sqlite3_column_text16() is called. A zero-terminator might 3641** need to be added to the string.</li> 3642** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3643** sqlite3_column_text16() is called. The content must be converted 3644** to UTF-16.</li> 3645** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3646** sqlite3_column_text() is called. The content must be converted 3647** to UTF-8.</li> 3648** </ul> 3649** 3650** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3651** not invalidate a prior pointer, though of course the content of the buffer 3652** that the prior pointer references will have been modified. Other kinds 3653** of conversion are done in place when it is possible, but sometimes they 3654** are not possible and in those cases prior pointers are invalidated. 3655** 3656** The safest and easiest to remember policy is to invoke these routines 3657** in one of the following ways: 3658** 3659** <ul> 3660** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3661** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3662** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3663** </ul> 3664** 3665** In other words, you should call sqlite3_column_text(), 3666** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3667** into the desired format, then invoke sqlite3_column_bytes() or 3668** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3669** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3670** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3671** with calls to sqlite3_column_bytes(). 3672** 3673** ^The pointers returned are valid until a type conversion occurs as 3674** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3675** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3676** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3677** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3678** [sqlite3_free()]. 3679** 3680** ^(If a memory allocation error occurs during the evaluation of any 3681** of these routines, a default value is returned. The default value 3682** is either the integer 0, the floating point number 0.0, or a NULL 3683** pointer. Subsequent calls to [sqlite3_errcode()] will return 3684** [SQLITE_NOMEM].)^ 3685*/ 3686SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3687SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3688SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3689SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol); 3690SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol); 3691SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3692SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3693SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3694SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol); 3695SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3696 3697/* 3698** CAPI3REF: Destroy A Prepared Statement Object 3699** 3700** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3701** ^If the most recent evaluation of the statement encountered no errors 3702** or if the statement is never been evaluated, then sqlite3_finalize() returns 3703** SQLITE_OK. ^If the most recent evaluation of statement S failed, then 3704** sqlite3_finalize(S) returns the appropriate [error code] or 3705** [extended error code]. 3706** 3707** ^The sqlite3_finalize(S) routine can be called at any point during 3708** the life cycle of [prepared statement] S: 3709** before statement S is ever evaluated, after 3710** one or more calls to [sqlite3_reset()], or after any call 3711** to [sqlite3_step()] regardless of whether or not the statement has 3712** completed execution. 3713** 3714** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op. 3715** 3716** The application must finalize every [prepared statement] in order to avoid 3717** resource leaks. It is a grievous error for the application to try to use 3718** a prepared statement after it has been finalized. Any use of a prepared 3719** statement after it has been finalized can result in undefined and 3720** undesirable behavior such as segfaults and heap corruption. 3721*/ 3722SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt); 3723 3724/* 3725** CAPI3REF: Reset A Prepared Statement Object 3726** 3727** The sqlite3_reset() function is called to reset a [prepared statement] 3728** object back to its initial state, ready to be re-executed. 3729** ^Any SQL statement variables that had values bound to them using 3730** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3731** Use [sqlite3_clear_bindings()] to reset the bindings. 3732** 3733** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3734** back to the beginning of its program. 3735** 3736** ^If the most recent call to [sqlite3_step(S)] for the 3737** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3738** or if [sqlite3_step(S)] has never before been called on S, 3739** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3740** 3741** ^If the most recent call to [sqlite3_step(S)] for the 3742** [prepared statement] S indicated an error, then 3743** [sqlite3_reset(S)] returns an appropriate [error code]. 3744** 3745** ^The [sqlite3_reset(S)] interface does not change the values 3746** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3747*/ 3748SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt); 3749 3750/* 3751** CAPI3REF: Create Or Redefine SQL Functions 3752** KEYWORDS: {function creation routines} 3753** KEYWORDS: {application-defined SQL function} 3754** KEYWORDS: {application-defined SQL functions} 3755** 3756** ^These functions (collectively known as "function creation routines") 3757** are used to add SQL functions or aggregates or to redefine the behavior 3758** of existing SQL functions or aggregates. The only differences between 3759** these routines are the text encoding expected for 3760** the second parameter (the name of the function being created) 3761** and the presence or absence of a destructor callback for 3762** the application data pointer. 3763** 3764** ^The first parameter is the [database connection] to which the SQL 3765** function is to be added. ^If an application uses more than one database 3766** connection then application-defined SQL functions must be added 3767** to each database connection separately. 3768** 3769** ^The second parameter is the name of the SQL function to be created or 3770** redefined. ^The length of the name is limited to 255 bytes in a UTF-8 3771** representation, exclusive of the zero-terminator. ^Note that the name 3772** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes. 3773** ^Any attempt to create a function with a longer name 3774** will result in [SQLITE_MISUSE] being returned. 3775** 3776** ^The third parameter (nArg) 3777** is the number of arguments that the SQL function or 3778** aggregate takes. ^If this parameter is -1, then the SQL function or 3779** aggregate may take any number of arguments between 0 and the limit 3780** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3781** parameter is less than -1 or greater than 127 then the behavior is 3782** undefined. 3783** 3784** ^The fourth parameter, eTextRep, specifies what 3785** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3786** its parameters. Every SQL function implementation must be able to work 3787** with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3788** more efficient with one encoding than another. ^An application may 3789** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3790** times with the same function but with different values of eTextRep. 3791** ^When multiple implementations of the same function are available, SQLite 3792** will pick the one that involves the least amount of data conversion. 3793** If there is only a single implementation which does not care what text 3794** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3795** 3796** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3797** function can gain access to this pointer using [sqlite3_user_data()].)^ 3798** 3799** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are 3800** pointers to C-language functions that implement the SQL function or 3801** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3802** callback only; NULL pointers must be passed as the xStep and xFinal 3803** parameters. ^An aggregate SQL function requires an implementation of xStep 3804** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing 3805** SQL function or aggregate, pass NULL pointers for all three function 3806** callbacks. 3807** 3808** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL, 3809** then it is destructor for the application data pointer. 3810** The destructor is invoked when the function is deleted, either by being 3811** overloaded or when the database connection closes.)^ 3812** ^The destructor is also invoked if the call to 3813** sqlite3_create_function_v2() fails. 3814** ^When the destructor callback of the tenth parameter is invoked, it 3815** is passed a single argument which is a copy of the application data 3816** pointer which was the fifth parameter to sqlite3_create_function_v2(). 3817** 3818** ^It is permitted to register multiple implementations of the same 3819** functions with the same name but with either differing numbers of 3820** arguments or differing preferred text encodings. ^SQLite will use 3821** the implementation that most closely matches the way in which the 3822** SQL function is used. ^A function implementation with a non-negative 3823** nArg parameter is a better match than a function implementation with 3824** a negative nArg. ^A function where the preferred text encoding 3825** matches the database encoding is a better 3826** match than a function where the encoding is different. 3827** ^A function where the encoding difference is between UTF16le and UTF16be 3828** is a closer match than a function where the encoding difference is 3829** between UTF8 and UTF16. 3830** 3831** ^Built-in functions may be overloaded by new application-defined functions. 3832** 3833** ^An application-defined function is permitted to call other 3834** SQLite interfaces. However, such calls must not 3835** close the database connection nor finalize or reset the prepared 3836** statement in which the function is running. 3837*/ 3838SQLITE_API int sqlite3_create_function( 3839 sqlite3 *db, 3840 const char *zFunctionName, 3841 int nArg, 3842 int eTextRep, 3843 void *pApp, 3844 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3845 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3846 void (*xFinal)(sqlite3_context*) 3847); 3848SQLITE_API int sqlite3_create_function16( 3849 sqlite3 *db, 3850 const void *zFunctionName, 3851 int nArg, 3852 int eTextRep, 3853 void *pApp, 3854 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3855 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3856 void (*xFinal)(sqlite3_context*) 3857); 3858SQLITE_API int sqlite3_create_function_v2( 3859 sqlite3 *db, 3860 const char *zFunctionName, 3861 int nArg, 3862 int eTextRep, 3863 void *pApp, 3864 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3865 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3866 void (*xFinal)(sqlite3_context*), 3867 void(*xDestroy)(void*) 3868); 3869 3870/* 3871** CAPI3REF: Text Encodings 3872** 3873** These constant define integer codes that represent the various 3874** text encodings supported by SQLite. 3875*/ 3876#define SQLITE_UTF8 1 3877#define SQLITE_UTF16LE 2 3878#define SQLITE_UTF16BE 3 3879#define SQLITE_UTF16 4 /* Use native byte order */ 3880#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3881#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3882 3883/* 3884** CAPI3REF: Deprecated Functions 3885** DEPRECATED 3886** 3887** These functions are [deprecated]. In order to maintain 3888** backwards compatibility with older code, these functions continue 3889** to be supported. However, new applications should avoid 3890** the use of these functions. To help encourage people to avoid 3891** using these functions, we are not going to tell you what they do. 3892*/ 3893#ifndef SQLITE_OMIT_DEPRECATED 3894SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3895SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3896SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3897SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void); 3898SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3899SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3900#endif 3901 3902/* 3903** CAPI3REF: Obtaining SQL Function Parameter Values 3904** 3905** The C-language implementation of SQL functions and aggregates uses 3906** this set of interface routines to access the parameter values on 3907** the function or aggregate. 3908** 3909** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3910** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3911** define callbacks that implement the SQL functions and aggregates. 3912** The 3rd parameter to these callbacks is an array of pointers to 3913** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3914** each parameter to the SQL function. These routines are used to 3915** extract values from the [sqlite3_value] objects. 3916** 3917** These routines work only with [protected sqlite3_value] objects. 3918** Any attempt to use these routines on an [unprotected sqlite3_value] 3919** object results in undefined behavior. 3920** 3921** ^These routines work just like the corresponding [column access functions] 3922** except that these routines take a single [protected sqlite3_value] object 3923** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3924** 3925** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3926** in the native byte-order of the host machine. ^The 3927** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3928** extract UTF-16 strings as big-endian and little-endian respectively. 3929** 3930** ^(The sqlite3_value_numeric_type() interface attempts to apply 3931** numeric affinity to the value. This means that an attempt is 3932** made to convert the value to an integer or floating point. If 3933** such a conversion is possible without loss of information (in other 3934** words, if the value is a string that looks like a number) 3935** then the conversion is performed. Otherwise no conversion occurs. 3936** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3937** 3938** Please pay particular attention to the fact that the pointer returned 3939** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3940** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3941** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3942** or [sqlite3_value_text16()]. 3943** 3944** These routines must be called from the same thread as 3945** the SQL function that supplied the [sqlite3_value*] parameters. 3946*/ 3947SQLITE_API const void *sqlite3_value_blob(sqlite3_value*); 3948SQLITE_API int sqlite3_value_bytes(sqlite3_value*); 3949SQLITE_API int sqlite3_value_bytes16(sqlite3_value*); 3950SQLITE_API double sqlite3_value_double(sqlite3_value*); 3951SQLITE_API int sqlite3_value_int(sqlite3_value*); 3952SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3953SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*); 3954SQLITE_API const void *sqlite3_value_text16(sqlite3_value*); 3955SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*); 3956SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*); 3957SQLITE_API int sqlite3_value_type(sqlite3_value*); 3958SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*); 3959 3960/* 3961** CAPI3REF: Obtain Aggregate Function Context 3962** 3963** Implementations of aggregate SQL functions use this 3964** routine to allocate memory for storing their state. 3965** 3966** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3967** for a particular aggregate function, SQLite 3968** allocates N of memory, zeroes out that memory, and returns a pointer 3969** to the new memory. ^On second and subsequent calls to 3970** sqlite3_aggregate_context() for the same aggregate function instance, 3971** the same buffer is returned. Sqlite3_aggregate_context() is normally 3972** called once for each invocation of the xStep callback and then one 3973** last time when the xFinal callback is invoked. ^(When no rows match 3974** an aggregate query, the xStep() callback of the aggregate function 3975** implementation is never called and xFinal() is called exactly once. 3976** In those cases, sqlite3_aggregate_context() might be called for the 3977** first time from within xFinal().)^ 3978** 3979** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3980** less than or equal to zero or if a memory allocate error occurs. 3981** 3982** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3983** determined by the N parameter on first successful call. Changing the 3984** value of N in subsequent call to sqlite3_aggregate_context() within 3985** the same aggregate function instance will not resize the memory 3986** allocation.)^ 3987** 3988** ^SQLite automatically frees the memory allocated by 3989** sqlite3_aggregate_context() when the aggregate query concludes. 3990** 3991** The first parameter must be a copy of the 3992** [sqlite3_context | SQL function context] that is the first parameter 3993** to the xStep or xFinal callback routine that implements the aggregate 3994** function. 3995** 3996** This routine must be called from the same thread in which 3997** the aggregate SQL function is running. 3998*/ 3999SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 4000 4001/* 4002** CAPI3REF: User Data For Functions 4003** 4004** ^The sqlite3_user_data() interface returns a copy of 4005** the pointer that was the pUserData parameter (the 5th parameter) 4006** of the [sqlite3_create_function()] 4007** and [sqlite3_create_function16()] routines that originally 4008** registered the application defined function. 4009** 4010** This routine must be called from the same thread in which 4011** the application-defined function is running. 4012*/ 4013SQLITE_API void *sqlite3_user_data(sqlite3_context*); 4014 4015/* 4016** CAPI3REF: Database Connection For Functions 4017** 4018** ^The sqlite3_context_db_handle() interface returns a copy of 4019** the pointer to the [database connection] (the 1st parameter) 4020** of the [sqlite3_create_function()] 4021** and [sqlite3_create_function16()] routines that originally 4022** registered the application defined function. 4023*/ 4024SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 4025 4026/* 4027** CAPI3REF: Function Auxiliary Data 4028** 4029** The following two functions may be used by scalar SQL functions to 4030** associate metadata with argument values. If the same value is passed to 4031** multiple invocations of the same SQL function during query execution, under 4032** some circumstances the associated metadata may be preserved. This may 4033** be used, for example, to add a regular-expression matching scalar 4034** function. The compiled version of the regular expression is stored as 4035** metadata associated with the SQL value passed as the regular expression 4036** pattern. The compiled regular expression can be reused on multiple 4037** invocations of the same function so that the original pattern string 4038** does not need to be recompiled on each invocation. 4039** 4040** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 4041** associated by the sqlite3_set_auxdata() function with the Nth argument 4042** value to the application-defined function. ^If no metadata has been ever 4043** been set for the Nth argument of the function, or if the corresponding 4044** function parameter has changed since the meta-data was set, 4045** then sqlite3_get_auxdata() returns a NULL pointer. 4046** 4047** ^The sqlite3_set_auxdata() interface saves the metadata 4048** pointed to by its 3rd parameter as the metadata for the N-th 4049** argument of the application-defined function. Subsequent 4050** calls to sqlite3_get_auxdata() might return this data, if it has 4051** not been destroyed. 4052** ^If it is not NULL, SQLite will invoke the destructor 4053** function given by the 4th parameter to sqlite3_set_auxdata() on 4054** the metadata when the corresponding function parameter changes 4055** or when the SQL statement completes, whichever comes first. 4056** 4057** SQLite is free to call the destructor and drop metadata on any 4058** parameter of any function at any time. ^The only guarantee is that 4059** the destructor will be called before the metadata is dropped. 4060** 4061** ^(In practice, metadata is preserved between function calls for 4062** expressions that are constant at compile time. This includes literal 4063** values and [parameters].)^ 4064** 4065** These routines must be called from the same thread in which 4066** the SQL function is running. 4067*/ 4068SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N); 4069SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 4070 4071 4072/* 4073** CAPI3REF: Constants Defining Special Destructor Behavior 4074** 4075** These are special values for the destructor that is passed in as the 4076** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 4077** argument is SQLITE_STATIC, it means that the content pointer is constant 4078** and will never change. It does not need to be destroyed. ^The 4079** SQLITE_TRANSIENT value means that the content will likely change in 4080** the near future and that SQLite should make its own private copy of 4081** the content before returning. 4082** 4083** The typedef is necessary to work around problems in certain 4084** C++ compilers. See ticket #2191. 4085*/ 4086typedef void (*sqlite3_destructor_type)(void*); 4087#define SQLITE_STATIC ((sqlite3_destructor_type)0) 4088#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 4089 4090/* 4091** CAPI3REF: Setting The Result Of An SQL Function 4092** 4093** These routines are used by the xFunc or xFinal callbacks that 4094** implement SQL functions and aggregates. See 4095** [sqlite3_create_function()] and [sqlite3_create_function16()] 4096** for additional information. 4097** 4098** These functions work very much like the [parameter binding] family of 4099** functions used to bind values to host parameters in prepared statements. 4100** Refer to the [SQL parameter] documentation for additional information. 4101** 4102** ^The sqlite3_result_blob() interface sets the result from 4103** an application-defined function to be the BLOB whose content is pointed 4104** to by the second parameter and which is N bytes long where N is the 4105** third parameter. 4106** 4107** ^The sqlite3_result_zeroblob() interfaces set the result of 4108** the application-defined function to be a BLOB containing all zero 4109** bytes and N bytes in size, where N is the value of the 2nd parameter. 4110** 4111** ^The sqlite3_result_double() interface sets the result from 4112** an application-defined function to be a floating point value specified 4113** by its 2nd argument. 4114** 4115** ^The sqlite3_result_error() and sqlite3_result_error16() functions 4116** cause the implemented SQL function to throw an exception. 4117** ^SQLite uses the string pointed to by the 4118** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 4119** as the text of an error message. ^SQLite interprets the error 4120** message string from sqlite3_result_error() as UTF-8. ^SQLite 4121** interprets the string from sqlite3_result_error16() as UTF-16 in native 4122** byte order. ^If the third parameter to sqlite3_result_error() 4123** or sqlite3_result_error16() is negative then SQLite takes as the error 4124** message all text up through the first zero character. 4125** ^If the third parameter to sqlite3_result_error() or 4126** sqlite3_result_error16() is non-negative then SQLite takes that many 4127** bytes (not characters) from the 2nd parameter as the error message. 4128** ^The sqlite3_result_error() and sqlite3_result_error16() 4129** routines make a private copy of the error message text before 4130** they return. Hence, the calling function can deallocate or 4131** modify the text after they return without harm. 4132** ^The sqlite3_result_error_code() function changes the error code 4133** returned by SQLite as a result of an error in a function. ^By default, 4134** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 4135** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 4136** 4137** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 4138** indicating that a string or BLOB is too long to represent. 4139** 4140** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 4141** indicating that a memory allocation failed. 4142** 4143** ^The sqlite3_result_int() interface sets the return value 4144** of the application-defined function to be the 32-bit signed integer 4145** value given in the 2nd argument. 4146** ^The sqlite3_result_int64() interface sets the return value 4147** of the application-defined function to be the 64-bit signed integer 4148** value given in the 2nd argument. 4149** 4150** ^The sqlite3_result_null() interface sets the return value 4151** of the application-defined function to be NULL. 4152** 4153** ^The sqlite3_result_text(), sqlite3_result_text16(), 4154** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 4155** set the return value of the application-defined function to be 4156** a text string which is represented as UTF-8, UTF-16 native byte order, 4157** UTF-16 little endian, or UTF-16 big endian, respectively. 4158** ^SQLite takes the text result from the application from 4159** the 2nd parameter of the sqlite3_result_text* interfaces. 4160** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4161** is negative, then SQLite takes result text from the 2nd parameter 4162** through the first zero character. 4163** ^If the 3rd parameter to the sqlite3_result_text* interfaces 4164** is non-negative, then as many bytes (not characters) of the text 4165** pointed to by the 2nd parameter are taken as the application-defined 4166** function result. If the 3rd parameter is non-negative, then it 4167** must be the byte offset into the string where the NUL terminator would 4168** appear if the string where NUL terminated. If any NUL characters occur 4169** in the string at a byte offset that is less than the value of the 3rd 4170** parameter, then the resulting string will contain embedded NULs and the 4171** result of expressions operating on strings with embedded NULs is undefined. 4172** ^If the 4th parameter to the sqlite3_result_text* interfaces 4173** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 4174** function as the destructor on the text or BLOB result when it has 4175** finished using that result. 4176** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 4177** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 4178** assumes that the text or BLOB result is in constant space and does not 4179** copy the content of the parameter nor call a destructor on the content 4180** when it has finished using that result. 4181** ^If the 4th parameter to the sqlite3_result_text* interfaces 4182** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 4183** then SQLite makes a copy of the result into space obtained from 4184** from [sqlite3_malloc()] before it returns. 4185** 4186** ^The sqlite3_result_value() interface sets the result of 4187** the application-defined function to be a copy the 4188** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 4189** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 4190** so that the [sqlite3_value] specified in the parameter may change or 4191** be deallocated after sqlite3_result_value() returns without harm. 4192** ^A [protected sqlite3_value] object may always be used where an 4193** [unprotected sqlite3_value] object is required, so either 4194** kind of [sqlite3_value] object can be used with this interface. 4195** 4196** If these routines are called from within the different thread 4197** than the one containing the application-defined function that received 4198** the [sqlite3_context] pointer, the results are undefined. 4199*/ 4200SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 4201SQLITE_API void sqlite3_result_double(sqlite3_context*, double); 4202SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int); 4203SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int); 4204SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*); 4205SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*); 4206SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int); 4207SQLITE_API void sqlite3_result_int(sqlite3_context*, int); 4208SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 4209SQLITE_API void sqlite3_result_null(sqlite3_context*); 4210SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 4211SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 4212SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 4213SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 4214SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 4215SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n); 4216 4217/* 4218** CAPI3REF: Define New Collating Sequences 4219** 4220** ^These functions add, remove, or modify a [collation] associated 4221** with the [database connection] specified as the first argument. 4222** 4223** ^The name of the collation is a UTF-8 string 4224** for sqlite3_create_collation() and sqlite3_create_collation_v2() 4225** and a UTF-16 string in native byte order for sqlite3_create_collation16(). 4226** ^Collation names that compare equal according to [sqlite3_strnicmp()] are 4227** considered to be the same name. 4228** 4229** ^(The third argument (eTextRep) must be one of the constants: 4230** <ul> 4231** <li> [SQLITE_UTF8], 4232** <li> [SQLITE_UTF16LE], 4233** <li> [SQLITE_UTF16BE], 4234** <li> [SQLITE_UTF16], or 4235** <li> [SQLITE_UTF16_ALIGNED]. 4236** </ul>)^ 4237** ^The eTextRep argument determines the encoding of strings passed 4238** to the collating function callback, xCallback. 4239** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep 4240** force strings to be UTF16 with native byte order. 4241** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin 4242** on an even byte address. 4243** 4244** ^The fourth argument, pArg, is an application data pointer that is passed 4245** through as the first argument to the collating function callback. 4246** 4247** ^The fifth argument, xCallback, is a pointer to the collating function. 4248** ^Multiple collating functions can be registered using the same name but 4249** with different eTextRep parameters and SQLite will use whichever 4250** function requires the least amount of data transformation. 4251** ^If the xCallback argument is NULL then the collating function is 4252** deleted. ^When all collating functions having the same name are deleted, 4253** that collation is no longer usable. 4254** 4255** ^The collating function callback is invoked with a copy of the pArg 4256** application data pointer and with two strings in the encoding specified 4257** by the eTextRep argument. The collating function must return an 4258** integer that is negative, zero, or positive 4259** if the first string is less than, equal to, or greater than the second, 4260** respectively. A collating function must always return the same answer 4261** given the same inputs. If two or more collating functions are registered 4262** to the same collation name (using different eTextRep values) then all 4263** must give an equivalent answer when invoked with equivalent strings. 4264** The collating function must obey the following properties for all 4265** strings A, B, and C: 4266** 4267** <ol> 4268** <li> If A==B then B==A. 4269** <li> If A==B and B==C then A==C. 4270** <li> If A<B THEN B>A. 4271** <li> If A<B and B<C then A<C. 4272** </ol> 4273** 4274** If a collating function fails any of the above constraints and that 4275** collating function is registered and used, then the behavior of SQLite 4276** is undefined. 4277** 4278** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 4279** with the addition that the xDestroy callback is invoked on pArg when 4280** the collating function is deleted. 4281** ^Collating functions are deleted when they are overridden by later 4282** calls to the collation creation functions or when the 4283** [database connection] is closed using [sqlite3_close()]. 4284** 4285** ^The xDestroy callback is <u>not</u> called if the 4286** sqlite3_create_collation_v2() function fails. Applications that invoke 4287** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 4288** check the return code and dispose of the application data pointer 4289** themselves rather than expecting SQLite to deal with it for them. 4290** This is different from every other SQLite interface. The inconsistency 4291** is unfortunate but cannot be changed without breaking backwards 4292** compatibility. 4293** 4294** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 4295*/ 4296SQLITE_API int sqlite3_create_collation( 4297 sqlite3*, 4298 const char *zName, 4299 int eTextRep, 4300 void *pArg, 4301 int(*xCompare)(void*,int,const void*,int,const void*) 4302); 4303SQLITE_API int sqlite3_create_collation_v2( 4304 sqlite3*, 4305 const char *zName, 4306 int eTextRep, 4307 void *pArg, 4308 int(*xCompare)(void*,int,const void*,int,const void*), 4309 void(*xDestroy)(void*) 4310); 4311SQLITE_API int sqlite3_create_collation16( 4312 sqlite3*, 4313 const void *zName, 4314 int eTextRep, 4315 void *pArg, 4316 int(*xCompare)(void*,int,const void*,int,const void*) 4317); 4318 4319/* 4320** CAPI3REF: Collation Needed Callbacks 4321** 4322** ^To avoid having to register all collation sequences before a database 4323** can be used, a single callback function may be registered with the 4324** [database connection] to be invoked whenever an undefined collation 4325** sequence is required. 4326** 4327** ^If the function is registered using the sqlite3_collation_needed() API, 4328** then it is passed the names of undefined collation sequences as strings 4329** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 4330** the names are passed as UTF-16 in machine native byte order. 4331** ^A call to either function replaces the existing collation-needed callback. 4332** 4333** ^(When the callback is invoked, the first argument passed is a copy 4334** of the second argument to sqlite3_collation_needed() or 4335** sqlite3_collation_needed16(). The second argument is the database 4336** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 4337** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 4338** sequence function required. The fourth parameter is the name of the 4339** required collation sequence.)^ 4340** 4341** The callback function should register the desired collation using 4342** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 4343** [sqlite3_create_collation_v2()]. 4344*/ 4345SQLITE_API int sqlite3_collation_needed( 4346 sqlite3*, 4347 void*, 4348 void(*)(void*,sqlite3*,int eTextRep,const char*) 4349); 4350SQLITE_API int sqlite3_collation_needed16( 4351 sqlite3*, 4352 void*, 4353 void(*)(void*,sqlite3*,int eTextRep,const void*) 4354); 4355 4356#ifdef SQLITE_HAS_CODEC 4357/* 4358** Specify the key for an encrypted database. This routine should be 4359** called right after sqlite3_open(). 4360** 4361** The code to implement this API is not available in the public release 4362** of SQLite. 4363*/ 4364SQLITE_API int sqlite3_key( 4365 sqlite3 *db, /* Database to be rekeyed */ 4366 const void *pKey, int nKey /* The key */ 4367); 4368 4369/* 4370** Change the key on an open database. If the current database is not 4371** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 4372** database is decrypted. 4373** 4374** The code to implement this API is not available in the public release 4375** of SQLite. 4376*/ 4377SQLITE_API int sqlite3_rekey( 4378 sqlite3 *db, /* Database to be rekeyed */ 4379 const void *pKey, int nKey /* The new key */ 4380); 4381 4382/* 4383** Specify the activation key for a SEE database. Unless 4384** activated, none of the SEE routines will work. 4385*/ 4386SQLITE_API void sqlite3_activate_see( 4387 const char *zPassPhrase /* Activation phrase */ 4388); 4389#endif 4390 4391#ifdef SQLITE_ENABLE_CEROD 4392/* 4393** Specify the activation key for a CEROD database. Unless 4394** activated, none of the CEROD routines will work. 4395*/ 4396SQLITE_API void sqlite3_activate_cerod( 4397 const char *zPassPhrase /* Activation phrase */ 4398); 4399#endif 4400 4401/* 4402** CAPI3REF: Suspend Execution For A Short Time 4403** 4404** The sqlite3_sleep() function causes the current thread to suspend execution 4405** for at least a number of milliseconds specified in its parameter. 4406** 4407** If the operating system does not support sleep requests with 4408** millisecond time resolution, then the time will be rounded up to 4409** the nearest second. The number of milliseconds of sleep actually 4410** requested from the operating system is returned. 4411** 4412** ^SQLite implements this interface by calling the xSleep() 4413** method of the default [sqlite3_vfs] object. If the xSleep() method 4414** of the default VFS is not implemented correctly, or not implemented at 4415** all, then the behavior of sqlite3_sleep() may deviate from the description 4416** in the previous paragraphs. 4417*/ 4418SQLITE_API int sqlite3_sleep(int); 4419 4420/* 4421** CAPI3REF: Name Of The Folder Holding Temporary Files 4422** 4423** ^(If this global variable is made to point to a string which is 4424** the name of a folder (a.k.a. directory), then all temporary files 4425** created by SQLite when using a built-in [sqlite3_vfs | VFS] 4426** will be placed in that directory.)^ ^If this variable 4427** is a NULL pointer, then SQLite performs a search for an appropriate 4428** temporary file directory. 4429** 4430** It is not safe to read or modify this variable in more than one 4431** thread at a time. It is not safe to read or modify this variable 4432** if a [database connection] is being used at the same time in a separate 4433** thread. 4434** It is intended that this variable be set once 4435** as part of process initialization and before any SQLite interface 4436** routines have been called and that this variable remain unchanged 4437** thereafter. 4438** 4439** ^The [temp_store_directory pragma] may modify this variable and cause 4440** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 4441** the [temp_store_directory pragma] always assumes that any string 4442** that this variable points to is held in memory obtained from 4443** [sqlite3_malloc] and the pragma may attempt to free that memory 4444** using [sqlite3_free]. 4445** Hence, if this variable is modified directly, either it should be 4446** made NULL or made to point to memory obtained from [sqlite3_malloc] 4447** or else the use of the [temp_store_directory pragma] should be avoided. 4448*/ 4449SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory; 4450 4451/* 4452** CAPI3REF: Test For Auto-Commit Mode 4453** KEYWORDS: {autocommit mode} 4454** 4455** ^The sqlite3_get_autocommit() interface returns non-zero or 4456** zero if the given database connection is or is not in autocommit mode, 4457** respectively. ^Autocommit mode is on by default. 4458** ^Autocommit mode is disabled by a [BEGIN] statement. 4459** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 4460** 4461** If certain kinds of errors occur on a statement within a multi-statement 4462** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 4463** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 4464** transaction might be rolled back automatically. The only way to 4465** find out whether SQLite automatically rolled back the transaction after 4466** an error is to use this function. 4467** 4468** If another thread changes the autocommit status of the database 4469** connection while this routine is running, then the return value 4470** is undefined. 4471*/ 4472SQLITE_API int sqlite3_get_autocommit(sqlite3*); 4473 4474/* 4475** CAPI3REF: Find The Database Handle Of A Prepared Statement 4476** 4477** ^The sqlite3_db_handle interface returns the [database connection] handle 4478** to which a [prepared statement] belongs. ^The [database connection] 4479** returned by sqlite3_db_handle is the same [database connection] 4480** that was the first argument 4481** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 4482** create the statement in the first place. 4483*/ 4484SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 4485 4486/* 4487** CAPI3REF: Return The Filename For A Database Connection 4488** 4489** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename 4490** associated with database N of connection D. ^The main database file 4491** has the name "main". If there is no attached database N on the database 4492** connection D, or if database N is a temporary or in-memory database, then 4493** a NULL pointer is returned. 4494** 4495** ^The filename returned by this function is the output of the 4496** xFullPathname method of the [VFS]. ^In other words, the filename 4497** will be an absolute pathname, even if the filename used 4498** to open the database originally was a URI or relative pathname. 4499*/ 4500SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName); 4501 4502/* 4503** CAPI3REF: Determine if a database is read-only 4504** 4505** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N 4506** of connection D is read-only, 0 if it is read/write, or -1 if N is not 4507** the name of a database on connection D. 4508*/ 4509SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName); 4510 4511/* 4512** CAPI3REF: Find the next prepared statement 4513** 4514** ^This interface returns a pointer to the next [prepared statement] after 4515** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 4516** then this interface returns a pointer to the first prepared statement 4517** associated with the database connection pDb. ^If no prepared statement 4518** satisfies the conditions of this routine, it returns NULL. 4519** 4520** The [database connection] pointer D in a call to 4521** [sqlite3_next_stmt(D,S)] must refer to an open database 4522** connection and in particular must not be a NULL pointer. 4523*/ 4524SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 4525 4526/* 4527** CAPI3REF: Commit And Rollback Notification Callbacks 4528** 4529** ^The sqlite3_commit_hook() interface registers a callback 4530** function to be invoked whenever a transaction is [COMMIT | committed]. 4531** ^Any callback set by a previous call to sqlite3_commit_hook() 4532** for the same database connection is overridden. 4533** ^The sqlite3_rollback_hook() interface registers a callback 4534** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 4535** ^Any callback set by a previous call to sqlite3_rollback_hook() 4536** for the same database connection is overridden. 4537** ^The pArg argument is passed through to the callback. 4538** ^If the callback on a commit hook function returns non-zero, 4539** then the commit is converted into a rollback. 4540** 4541** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 4542** return the P argument from the previous call of the same function 4543** on the same [database connection] D, or NULL for 4544** the first call for each function on D. 4545** 4546** The commit and rollback hook callbacks are not reentrant. 4547** The callback implementation must not do anything that will modify 4548** the database connection that invoked the callback. Any actions 4549** to modify the database connection must be deferred until after the 4550** completion of the [sqlite3_step()] call that triggered the commit 4551** or rollback hook in the first place. 4552** Note that running any other SQL statements, including SELECT statements, 4553** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify 4554** the database connections for the meaning of "modify" in this paragraph. 4555** 4556** ^Registering a NULL function disables the callback. 4557** 4558** ^When the commit hook callback routine returns zero, the [COMMIT] 4559** operation is allowed to continue normally. ^If the commit hook 4560** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 4561** ^The rollback hook is invoked on a rollback that results from a commit 4562** hook returning non-zero, just as it would be with any other rollback. 4563** 4564** ^For the purposes of this API, a transaction is said to have been 4565** rolled back if an explicit "ROLLBACK" statement is executed, or 4566** an error or constraint causes an implicit rollback to occur. 4567** ^The rollback callback is not invoked if a transaction is 4568** automatically rolled back because the database connection is closed. 4569** 4570** See also the [sqlite3_update_hook()] interface. 4571*/ 4572SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 4573SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 4574 4575/* 4576** CAPI3REF: Data Change Notification Callbacks 4577** 4578** ^The sqlite3_update_hook() interface registers a callback function 4579** with the [database connection] identified by the first argument 4580** to be invoked whenever a row is updated, inserted or deleted. 4581** ^Any callback set by a previous call to this function 4582** for the same database connection is overridden. 4583** 4584** ^The second argument is a pointer to the function to invoke when a 4585** row is updated, inserted or deleted. 4586** ^The first argument to the callback is a copy of the third argument 4587** to sqlite3_update_hook(). 4588** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 4589** or [SQLITE_UPDATE], depending on the operation that caused the callback 4590** to be invoked. 4591** ^The third and fourth arguments to the callback contain pointers to the 4592** database and table name containing the affected row. 4593** ^The final callback parameter is the [rowid] of the row. 4594** ^In the case of an update, this is the [rowid] after the update takes place. 4595** 4596** ^(The update hook is not invoked when internal system tables are 4597** modified (i.e. sqlite_master and sqlite_sequence).)^ 4598** 4599** ^In the current implementation, the update hook 4600** is not invoked when duplication rows are deleted because of an 4601** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 4602** invoked when rows are deleted using the [truncate optimization]. 4603** The exceptions defined in this paragraph might change in a future 4604** release of SQLite. 4605** 4606** The update hook implementation must not do anything that will modify 4607** the database connection that invoked the update hook. Any actions 4608** to modify the database connection must be deferred until after the 4609** completion of the [sqlite3_step()] call that triggered the update hook. 4610** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 4611** database connections for the meaning of "modify" in this paragraph. 4612** 4613** ^The sqlite3_update_hook(D,C,P) function 4614** returns the P argument from the previous call 4615** on the same [database connection] D, or NULL for 4616** the first call on D. 4617** 4618** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 4619** interfaces. 4620*/ 4621SQLITE_API void *sqlite3_update_hook( 4622 sqlite3*, 4623 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 4624 void* 4625); 4626 4627/* 4628** CAPI3REF: Enable Or Disable Shared Pager Cache 4629** KEYWORDS: {shared cache} 4630** 4631** ^(This routine enables or disables the sharing of the database cache 4632** and schema data structures between [database connection | connections] 4633** to the same database. Sharing is enabled if the argument is true 4634** and disabled if the argument is false.)^ 4635** 4636** ^Cache sharing is enabled and disabled for an entire process. 4637** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 4638** sharing was enabled or disabled for each thread separately. 4639** 4640** ^(The cache sharing mode set by this interface effects all subsequent 4641** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 4642** Existing database connections continue use the sharing mode 4643** that was in effect at the time they were opened.)^ 4644** 4645** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 4646** successfully. An [error code] is returned otherwise.)^ 4647** 4648** ^Shared cache is disabled by default. But this might change in 4649** future releases of SQLite. Applications that care about shared 4650** cache setting should set it explicitly. 4651** 4652** See Also: [SQLite Shared-Cache Mode] 4653*/ 4654SQLITE_API int sqlite3_enable_shared_cache(int); 4655 4656/* 4657** CAPI3REF: Attempt To Free Heap Memory 4658** 4659** ^The sqlite3_release_memory() interface attempts to free N bytes 4660** of heap memory by deallocating non-essential memory allocations 4661** held by the database library. Memory used to cache database 4662** pages to improve performance is an example of non-essential memory. 4663** ^sqlite3_release_memory() returns the number of bytes actually freed, 4664** which might be more or less than the amount requested. 4665** ^The sqlite3_release_memory() routine is a no-op returning zero 4666** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4667** 4668** See also: [sqlite3_db_release_memory()] 4669*/ 4670SQLITE_API int sqlite3_release_memory(int); 4671 4672/* 4673** CAPI3REF: Free Memory Used By A Database Connection 4674** 4675** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap 4676** memory as possible from database connection D. Unlike the 4677** [sqlite3_release_memory()] interface, this interface is effect even 4678** when then [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is 4679** omitted. 4680** 4681** See also: [sqlite3_release_memory()] 4682*/ 4683SQLITE_API int sqlite3_db_release_memory(sqlite3*); 4684 4685/* 4686** CAPI3REF: Impose A Limit On Heap Size 4687** 4688** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the 4689** soft limit on the amount of heap memory that may be allocated by SQLite. 4690** ^SQLite strives to keep heap memory utilization below the soft heap 4691** limit by reducing the number of pages held in the page cache 4692** as heap memory usages approaches the limit. 4693** ^The soft heap limit is "soft" because even though SQLite strives to stay 4694** below the limit, it will exceed the limit rather than generate 4695** an [SQLITE_NOMEM] error. In other words, the soft heap limit 4696** is advisory only. 4697** 4698** ^The return value from sqlite3_soft_heap_limit64() is the size of 4699** the soft heap limit prior to the call, or negative in the case of an 4700** error. ^If the argument N is negative 4701** then no change is made to the soft heap limit. Hence, the current 4702** size of the soft heap limit can be determined by invoking 4703** sqlite3_soft_heap_limit64() with a negative argument. 4704** 4705** ^If the argument N is zero then the soft heap limit is disabled. 4706** 4707** ^(The soft heap limit is not enforced in the current implementation 4708** if one or more of following conditions are true: 4709** 4710** <ul> 4711** <li> The soft heap limit is set to zero. 4712** <li> Memory accounting is disabled using a combination of the 4713** [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and 4714** the [SQLITE_DEFAULT_MEMSTATUS] compile-time option. 4715** <li> An alternative page cache implementation is specified using 4716** [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...). 4717** <li> The page cache allocates from its own memory pool supplied 4718** by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than 4719** from the heap. 4720** </ul>)^ 4721** 4722** Beginning with SQLite version 3.7.3, the soft heap limit is enforced 4723** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT] 4724** compile-time option is invoked. With [SQLITE_ENABLE_MEMORY_MANAGEMENT], 4725** the soft heap limit is enforced on every memory allocation. Without 4726** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced 4727** when memory is allocated by the page cache. Testing suggests that because 4728** the page cache is the predominate memory user in SQLite, most 4729** applications will achieve adequate soft heap limit enforcement without 4730** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT]. 4731** 4732** The circumstances under which SQLite will enforce the soft heap limit may 4733** changes in future releases of SQLite. 4734*/ 4735SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N); 4736 4737/* 4738** CAPI3REF: Deprecated Soft Heap Limit Interface 4739** DEPRECATED 4740** 4741** This is a deprecated version of the [sqlite3_soft_heap_limit64()] 4742** interface. This routine is provided for historical compatibility 4743** only. All new applications should use the 4744** [sqlite3_soft_heap_limit64()] interface rather than this one. 4745*/ 4746SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N); 4747 4748 4749/* 4750** CAPI3REF: Extract Metadata About A Column Of A Table 4751** 4752** ^This routine returns metadata about a specific column of a specific 4753** database table accessible using the [database connection] handle 4754** passed as the first function argument. 4755** 4756** ^The column is identified by the second, third and fourth parameters to 4757** this function. ^The second parameter is either the name of the database 4758** (i.e. "main", "temp", or an attached database) containing the specified 4759** table or NULL. ^If it is NULL, then all attached databases are searched 4760** for the table using the same algorithm used by the database engine to 4761** resolve unqualified table references. 4762** 4763** ^The third and fourth parameters to this function are the table and column 4764** name of the desired column, respectively. Neither of these parameters 4765** may be NULL. 4766** 4767** ^Metadata is returned by writing to the memory locations passed as the 5th 4768** and subsequent parameters to this function. ^Any of these arguments may be 4769** NULL, in which case the corresponding element of metadata is omitted. 4770** 4771** ^(<blockquote> 4772** <table border="1"> 4773** <tr><th> Parameter <th> Output<br>Type <th> Description 4774** 4775** <tr><td> 5th <td> const char* <td> Data type 4776** <tr><td> 6th <td> const char* <td> Name of default collation sequence 4777** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 4778** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 4779** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 4780** </table> 4781** </blockquote>)^ 4782** 4783** ^The memory pointed to by the character pointers returned for the 4784** declaration type and collation sequence is valid only until the next 4785** call to any SQLite API function. 4786** 4787** ^If the specified table is actually a view, an [error code] is returned. 4788** 4789** ^If the specified column is "rowid", "oid" or "_rowid_" and an 4790** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 4791** parameters are set for the explicitly declared column. ^(If there is no 4792** explicitly declared [INTEGER PRIMARY KEY] column, then the output 4793** parameters are set as follows: 4794** 4795** <pre> 4796** data type: "INTEGER" 4797** collation sequence: "BINARY" 4798** not null: 0 4799** primary key: 1 4800** auto increment: 0 4801** </pre>)^ 4802** 4803** ^(This function may load one or more schemas from database files. If an 4804** error occurs during this process, or if the requested table or column 4805** cannot be found, an [error code] is returned and an error message left 4806** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4807** 4808** ^This API is only available if the library was compiled with the 4809** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4810*/ 4811SQLITE_API int sqlite3_table_column_metadata( 4812 sqlite3 *db, /* Connection handle */ 4813 const char *zDbName, /* Database name or NULL */ 4814 const char *zTableName, /* Table name */ 4815 const char *zColumnName, /* Column name */ 4816 char const **pzDataType, /* OUTPUT: Declared data type */ 4817 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4818 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4819 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4820 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4821); 4822 4823/* 4824** CAPI3REF: Load An Extension 4825** 4826** ^This interface loads an SQLite extension library from the named file. 4827** 4828** ^The sqlite3_load_extension() interface attempts to load an 4829** SQLite extension library contained in the file zFile. 4830** 4831** ^The entry point is zProc. 4832** ^zProc may be 0, in which case the name of the entry point 4833** defaults to "sqlite3_extension_init". 4834** ^The sqlite3_load_extension() interface returns 4835** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4836** ^If an error occurs and pzErrMsg is not 0, then the 4837** [sqlite3_load_extension()] interface shall attempt to 4838** fill *pzErrMsg with error message text stored in memory 4839** obtained from [sqlite3_malloc()]. The calling function 4840** should free this memory by calling [sqlite3_free()]. 4841** 4842** ^Extension loading must be enabled using 4843** [sqlite3_enable_load_extension()] prior to calling this API, 4844** otherwise an error will be returned. 4845** 4846** See also the [load_extension() SQL function]. 4847*/ 4848SQLITE_API int sqlite3_load_extension( 4849 sqlite3 *db, /* Load the extension into this database connection */ 4850 const char *zFile, /* Name of the shared library containing extension */ 4851 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4852 char **pzErrMsg /* Put error message here if not 0 */ 4853); 4854 4855/* 4856** CAPI3REF: Enable Or Disable Extension Loading 4857** 4858** ^So as not to open security holes in older applications that are 4859** unprepared to deal with extension loading, and as a means of disabling 4860** extension loading while evaluating user-entered SQL, the following API 4861** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4862** 4863** ^Extension loading is off by default. See ticket #1863. 4864** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4865** to turn extension loading on and call it with onoff==0 to turn 4866** it back off again. 4867*/ 4868SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4869 4870/* 4871** CAPI3REF: Automatically Load Statically Linked Extensions 4872** 4873** ^This interface causes the xEntryPoint() function to be invoked for 4874** each new [database connection] that is created. The idea here is that 4875** xEntryPoint() is the entry point for a statically linked SQLite extension 4876** that is to be automatically loaded into all new database connections. 4877** 4878** ^(Even though the function prototype shows that xEntryPoint() takes 4879** no arguments and returns void, SQLite invokes xEntryPoint() with three 4880** arguments and expects and integer result as if the signature of the 4881** entry point where as follows: 4882** 4883** <blockquote><pre> 4884** int xEntryPoint( 4885** sqlite3 *db, 4886** const char **pzErrMsg, 4887** const struct sqlite3_api_routines *pThunk 4888** ); 4889** </pre></blockquote>)^ 4890** 4891** If the xEntryPoint routine encounters an error, it should make *pzErrMsg 4892** point to an appropriate error message (obtained from [sqlite3_mprintf()]) 4893** and return an appropriate [error code]. ^SQLite ensures that *pzErrMsg 4894** is NULL before calling the xEntryPoint(). ^SQLite will invoke 4895** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns. ^If any 4896** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()], 4897** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail. 4898** 4899** ^Calling sqlite3_auto_extension(X) with an entry point X that is already 4900** on the list of automatic extensions is a harmless no-op. ^No entry point 4901** will be called more than once for each database connection that is opened. 4902** 4903** See also: [sqlite3_reset_auto_extension()]. 4904*/ 4905SQLITE_API int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4906 4907/* 4908** CAPI3REF: Reset Automatic Extension Loading 4909** 4910** ^This interface disables all automatic extensions previously 4911** registered using [sqlite3_auto_extension()]. 4912*/ 4913SQLITE_API void sqlite3_reset_auto_extension(void); 4914 4915/* 4916** The interface to the virtual-table mechanism is currently considered 4917** to be experimental. The interface might change in incompatible ways. 4918** If this is a problem for you, do not use the interface at this time. 4919** 4920** When the virtual-table mechanism stabilizes, we will declare the 4921** interface fixed, support it indefinitely, and remove this comment. 4922*/ 4923 4924/* 4925** Structures used by the virtual table interface 4926*/ 4927typedef struct sqlite3_vtab sqlite3_vtab; 4928typedef struct sqlite3_index_info sqlite3_index_info; 4929typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4930typedef struct sqlite3_module sqlite3_module; 4931 4932/* 4933** CAPI3REF: Virtual Table Object 4934** KEYWORDS: sqlite3_module {virtual table module} 4935** 4936** This structure, sometimes called a "virtual table module", 4937** defines the implementation of a [virtual tables]. 4938** This structure consists mostly of methods for the module. 4939** 4940** ^A virtual table module is created by filling in a persistent 4941** instance of this structure and passing a pointer to that instance 4942** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4943** ^The registration remains valid until it is replaced by a different 4944** module or until the [database connection] closes. The content 4945** of this structure must not change while it is registered with 4946** any database connection. 4947*/ 4948struct sqlite3_module { 4949 int iVersion; 4950 int (*xCreate)(sqlite3*, void *pAux, 4951 int argc, const char *const*argv, 4952 sqlite3_vtab **ppVTab, char**); 4953 int (*xConnect)(sqlite3*, void *pAux, 4954 int argc, const char *const*argv, 4955 sqlite3_vtab **ppVTab, char**); 4956 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4957 int (*xDisconnect)(sqlite3_vtab *pVTab); 4958 int (*xDestroy)(sqlite3_vtab *pVTab); 4959 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4960 int (*xClose)(sqlite3_vtab_cursor*); 4961 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4962 int argc, sqlite3_value **argv); 4963 int (*xNext)(sqlite3_vtab_cursor*); 4964 int (*xEof)(sqlite3_vtab_cursor*); 4965 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4966 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4967 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4968 int (*xBegin)(sqlite3_vtab *pVTab); 4969 int (*xSync)(sqlite3_vtab *pVTab); 4970 int (*xCommit)(sqlite3_vtab *pVTab); 4971 int (*xRollback)(sqlite3_vtab *pVTab); 4972 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4973 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4974 void **ppArg); 4975 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4976 /* The methods above are in version 1 of the sqlite_module object. Those 4977 ** below are for version 2 and greater. */ 4978 int (*xSavepoint)(sqlite3_vtab *pVTab, int); 4979 int (*xRelease)(sqlite3_vtab *pVTab, int); 4980 int (*xRollbackTo)(sqlite3_vtab *pVTab, int); 4981}; 4982 4983/* 4984** CAPI3REF: Virtual Table Indexing Information 4985** KEYWORDS: sqlite3_index_info 4986** 4987** The sqlite3_index_info structure and its substructures is used as part 4988** of the [virtual table] interface to 4989** pass information into and receive the reply from the [xBestIndex] 4990** method of a [virtual table module]. The fields under **Inputs** are the 4991** inputs to xBestIndex and are read-only. xBestIndex inserts its 4992** results into the **Outputs** fields. 4993** 4994** ^(The aConstraint[] array records WHERE clause constraints of the form: 4995** 4996** <blockquote>column OP expr</blockquote> 4997** 4998** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4999** stored in aConstraint[].op using one of the 5000** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^ 5001** ^(The index of the column is stored in 5002** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 5003** expr on the right-hand side can be evaluated (and thus the constraint 5004** is usable) and false if it cannot.)^ 5005** 5006** ^The optimizer automatically inverts terms of the form "expr OP column" 5007** and makes other simplifications to the WHERE clause in an attempt to 5008** get as many WHERE clause terms into the form shown above as possible. 5009** ^The aConstraint[] array only reports WHERE clause terms that are 5010** relevant to the particular virtual table being queried. 5011** 5012** ^Information about the ORDER BY clause is stored in aOrderBy[]. 5013** ^Each term of aOrderBy records a column of the ORDER BY clause. 5014** 5015** The [xBestIndex] method must fill aConstraintUsage[] with information 5016** about what parameters to pass to xFilter. ^If argvIndex>0 then 5017** the right-hand side of the corresponding aConstraint[] is evaluated 5018** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 5019** is true, then the constraint is assumed to be fully handled by the 5020** virtual table and is not checked again by SQLite.)^ 5021** 5022** ^The idxNum and idxPtr values are recorded and passed into the 5023** [xFilter] method. 5024** ^[sqlite3_free()] is used to free idxPtr if and only if 5025** needToFreeIdxPtr is true. 5026** 5027** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 5028** the correct order to satisfy the ORDER BY clause so that no separate 5029** sorting step is required. 5030** 5031** ^The estimatedCost value is an estimate of the cost of doing the 5032** particular lookup. A full scan of a table with N entries should have 5033** a cost of N. A binary search of a table of N entries should have a 5034** cost of approximately log(N). 5035*/ 5036struct sqlite3_index_info { 5037 /* Inputs */ 5038 int nConstraint; /* Number of entries in aConstraint */ 5039 struct sqlite3_index_constraint { 5040 int iColumn; /* Column on left-hand side of constraint */ 5041 unsigned char op; /* Constraint operator */ 5042 unsigned char usable; /* True if this constraint is usable */ 5043 int iTermOffset; /* Used internally - xBestIndex should ignore */ 5044 } *aConstraint; /* Table of WHERE clause constraints */ 5045 int nOrderBy; /* Number of terms in the ORDER BY clause */ 5046 struct sqlite3_index_orderby { 5047 int iColumn; /* Column number */ 5048 unsigned char desc; /* True for DESC. False for ASC. */ 5049 } *aOrderBy; /* The ORDER BY clause */ 5050 /* Outputs */ 5051 struct sqlite3_index_constraint_usage { 5052 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 5053 unsigned char omit; /* Do not code a test for this constraint */ 5054 } *aConstraintUsage; 5055 int idxNum; /* Number used to identify the index */ 5056 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 5057 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 5058 int orderByConsumed; /* True if output is already ordered */ 5059 double estimatedCost; /* Estimated cost of using this index */ 5060}; 5061 5062/* 5063** CAPI3REF: Virtual Table Constraint Operator Codes 5064** 5065** These macros defined the allowed values for the 5066** [sqlite3_index_info].aConstraint[].op field. Each value represents 5067** an operator that is part of a constraint term in the wHERE clause of 5068** a query that uses a [virtual table]. 5069*/ 5070#define SQLITE_INDEX_CONSTRAINT_EQ 2 5071#define SQLITE_INDEX_CONSTRAINT_GT 4 5072#define SQLITE_INDEX_CONSTRAINT_LE 8 5073#define SQLITE_INDEX_CONSTRAINT_LT 16 5074#define SQLITE_INDEX_CONSTRAINT_GE 32 5075#define SQLITE_INDEX_CONSTRAINT_MATCH 64 5076 5077/* 5078** CAPI3REF: Register A Virtual Table Implementation 5079** 5080** ^These routines are used to register a new [virtual table module] name. 5081** ^Module names must be registered before 5082** creating a new [virtual table] using the module and before using a 5083** preexisting [virtual table] for the module. 5084** 5085** ^The module name is registered on the [database connection] specified 5086** by the first parameter. ^The name of the module is given by the 5087** second parameter. ^The third parameter is a pointer to 5088** the implementation of the [virtual table module]. ^The fourth 5089** parameter is an arbitrary client data pointer that is passed through 5090** into the [xCreate] and [xConnect] methods of the virtual table module 5091** when a new virtual table is be being created or reinitialized. 5092** 5093** ^The sqlite3_create_module_v2() interface has a fifth parameter which 5094** is a pointer to a destructor for the pClientData. ^SQLite will 5095** invoke the destructor function (if it is not NULL) when SQLite 5096** no longer needs the pClientData pointer. ^The destructor will also 5097** be invoked if the call to sqlite3_create_module_v2() fails. 5098** ^The sqlite3_create_module() 5099** interface is equivalent to sqlite3_create_module_v2() with a NULL 5100** destructor. 5101*/ 5102SQLITE_API int sqlite3_create_module( 5103 sqlite3 *db, /* SQLite connection to register module with */ 5104 const char *zName, /* Name of the module */ 5105 const sqlite3_module *p, /* Methods for the module */ 5106 void *pClientData /* Client data for xCreate/xConnect */ 5107); 5108SQLITE_API int sqlite3_create_module_v2( 5109 sqlite3 *db, /* SQLite connection to register module with */ 5110 const char *zName, /* Name of the module */ 5111 const sqlite3_module *p, /* Methods for the module */ 5112 void *pClientData, /* Client data for xCreate/xConnect */ 5113 void(*xDestroy)(void*) /* Module destructor function */ 5114); 5115 5116/* 5117** CAPI3REF: Virtual Table Instance Object 5118** KEYWORDS: sqlite3_vtab 5119** 5120** Every [virtual table module] implementation uses a subclass 5121** of this object to describe a particular instance 5122** of the [virtual table]. Each subclass will 5123** be tailored to the specific needs of the module implementation. 5124** The purpose of this superclass is to define certain fields that are 5125** common to all module implementations. 5126** 5127** ^Virtual tables methods can set an error message by assigning a 5128** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 5129** take care that any prior string is freed by a call to [sqlite3_free()] 5130** prior to assigning a new string to zErrMsg. ^After the error message 5131** is delivered up to the client application, the string will be automatically 5132** freed by sqlite3_free() and the zErrMsg field will be zeroed. 5133*/ 5134struct sqlite3_vtab { 5135 const sqlite3_module *pModule; /* The module for this virtual table */ 5136 int nRef; /* NO LONGER USED */ 5137 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 5138 /* Virtual table implementations will typically add additional fields */ 5139}; 5140 5141/* 5142** CAPI3REF: Virtual Table Cursor Object 5143** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 5144** 5145** Every [virtual table module] implementation uses a subclass of the 5146** following structure to describe cursors that point into the 5147** [virtual table] and are used 5148** to loop through the virtual table. Cursors are created using the 5149** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 5150** by the [sqlite3_module.xClose | xClose] method. Cursors are used 5151** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 5152** of the module. Each module implementation will define 5153** the content of a cursor structure to suit its own needs. 5154** 5155** This superclass exists in order to define fields of the cursor that 5156** are common to all implementations. 5157*/ 5158struct sqlite3_vtab_cursor { 5159 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 5160 /* Virtual table implementations will typically add additional fields */ 5161}; 5162 5163/* 5164** CAPI3REF: Declare The Schema Of A Virtual Table 5165** 5166** ^The [xCreate] and [xConnect] methods of a 5167** [virtual table module] call this interface 5168** to declare the format (the names and datatypes of the columns) of 5169** the virtual tables they implement. 5170*/ 5171SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 5172 5173/* 5174** CAPI3REF: Overload A Function For A Virtual Table 5175** 5176** ^(Virtual tables can provide alternative implementations of functions 5177** using the [xFindFunction] method of the [virtual table module]. 5178** But global versions of those functions 5179** must exist in order to be overloaded.)^ 5180** 5181** ^(This API makes sure a global version of a function with a particular 5182** name and number of parameters exists. If no such function exists 5183** before this API is called, a new function is created.)^ ^The implementation 5184** of the new function always causes an exception to be thrown. So 5185** the new function is not good for anything by itself. Its only 5186** purpose is to be a placeholder function that can be overloaded 5187** by a [virtual table]. 5188*/ 5189SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 5190 5191/* 5192** The interface to the virtual-table mechanism defined above (back up 5193** to a comment remarkably similar to this one) is currently considered 5194** to be experimental. The interface might change in incompatible ways. 5195** If this is a problem for you, do not use the interface at this time. 5196** 5197** When the virtual-table mechanism stabilizes, we will declare the 5198** interface fixed, support it indefinitely, and remove this comment. 5199*/ 5200 5201/* 5202** CAPI3REF: A Handle To An Open BLOB 5203** KEYWORDS: {BLOB handle} {BLOB handles} 5204** 5205** An instance of this object represents an open BLOB on which 5206** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 5207** ^Objects of this type are created by [sqlite3_blob_open()] 5208** and destroyed by [sqlite3_blob_close()]. 5209** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 5210** can be used to read or write small subsections of the BLOB. 5211** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 5212*/ 5213typedef struct sqlite3_blob sqlite3_blob; 5214 5215/* 5216** CAPI3REF: Open A BLOB For Incremental I/O 5217** 5218** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 5219** in row iRow, column zColumn, table zTable in database zDb; 5220** in other words, the same BLOB that would be selected by: 5221** 5222** <pre> 5223** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 5224** </pre>)^ 5225** 5226** ^If the flags parameter is non-zero, then the BLOB is opened for read 5227** and write access. ^If it is zero, the BLOB is opened for read access. 5228** ^It is not possible to open a column that is part of an index or primary 5229** key for writing. ^If [foreign key constraints] are enabled, it is 5230** not possible to open a column that is part of a [child key] for writing. 5231** 5232** ^Note that the database name is not the filename that contains 5233** the database but rather the symbolic name of the database that 5234** appears after the AS keyword when the database is connected using [ATTACH]. 5235** ^For the main database file, the database name is "main". 5236** ^For TEMP tables, the database name is "temp". 5237** 5238** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 5239** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 5240** to be a null pointer.)^ 5241** ^This function sets the [database connection] error code and message 5242** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 5243** functions. ^Note that the *ppBlob variable is always initialized in a 5244** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 5245** regardless of the success or failure of this routine. 5246** 5247** ^(If the row that a BLOB handle points to is modified by an 5248** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 5249** then the BLOB handle is marked as "expired". 5250** This is true if any column of the row is changed, even a column 5251** other than the one the BLOB handle is open on.)^ 5252** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 5253** an expired BLOB handle fail with a return code of [SQLITE_ABORT]. 5254** ^(Changes written into a BLOB prior to the BLOB expiring are not 5255** rolled back by the expiration of the BLOB. Such changes will eventually 5256** commit if the transaction continues to completion.)^ 5257** 5258** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 5259** the opened blob. ^The size of a blob may not be changed by this 5260** interface. Use the [UPDATE] SQL command to change the size of a 5261** blob. 5262** 5263** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 5264** and the built-in [zeroblob] SQL function can be used, if desired, 5265** to create an empty, zero-filled blob in which to read or write using 5266** this interface. 5267** 5268** To avoid a resource leak, every open [BLOB handle] should eventually 5269** be released by a call to [sqlite3_blob_close()]. 5270*/ 5271SQLITE_API int sqlite3_blob_open( 5272 sqlite3*, 5273 const char *zDb, 5274 const char *zTable, 5275 const char *zColumn, 5276 sqlite3_int64 iRow, 5277 int flags, 5278 sqlite3_blob **ppBlob 5279); 5280 5281/* 5282** CAPI3REF: Move a BLOB Handle to a New Row 5283** 5284** ^This function is used to move an existing blob handle so that it points 5285** to a different row of the same database table. ^The new row is identified 5286** by the rowid value passed as the second argument. Only the row can be 5287** changed. ^The database, table and column on which the blob handle is open 5288** remain the same. Moving an existing blob handle to a new row can be 5289** faster than closing the existing handle and opening a new one. 5290** 5291** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] - 5292** it must exist and there must be either a blob or text value stored in 5293** the nominated column.)^ ^If the new row is not present in the table, or if 5294** it does not contain a blob or text value, or if another error occurs, an 5295** SQLite error code is returned and the blob handle is considered aborted. 5296** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or 5297** [sqlite3_blob_reopen()] on an aborted blob handle immediately return 5298** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle 5299** always returns zero. 5300** 5301** ^This function sets the database handle error code and message. 5302*/ 5303SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64); 5304 5305/* 5306** CAPI3REF: Close A BLOB Handle 5307** 5308** ^Closes an open [BLOB handle]. 5309** 5310** ^Closing a BLOB shall cause the current transaction to commit 5311** if there are no other BLOBs, no pending prepared statements, and the 5312** database connection is in [autocommit mode]. 5313** ^If any writes were made to the BLOB, they might be held in cache 5314** until the close operation if they will fit. 5315** 5316** ^(Closing the BLOB often forces the changes 5317** out to disk and so if any I/O errors occur, they will likely occur 5318** at the time when the BLOB is closed. Any errors that occur during 5319** closing are reported as a non-zero return value.)^ 5320** 5321** ^(The BLOB is closed unconditionally. Even if this routine returns 5322** an error code, the BLOB is still closed.)^ 5323** 5324** ^Calling this routine with a null pointer (such as would be returned 5325** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 5326*/ 5327SQLITE_API int sqlite3_blob_close(sqlite3_blob *); 5328 5329/* 5330** CAPI3REF: Return The Size Of An Open BLOB 5331** 5332** ^Returns the size in bytes of the BLOB accessible via the 5333** successfully opened [BLOB handle] in its only argument. ^The 5334** incremental blob I/O routines can only read or overwriting existing 5335** blob content; they cannot change the size of a blob. 5336** 5337** This routine only works on a [BLOB handle] which has been created 5338** by a prior successful call to [sqlite3_blob_open()] and which has not 5339** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5340** to this routine results in undefined and probably undesirable behavior. 5341*/ 5342SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *); 5343 5344/* 5345** CAPI3REF: Read Data From A BLOB Incrementally 5346** 5347** ^(This function is used to read data from an open [BLOB handle] into a 5348** caller-supplied buffer. N bytes of data are copied into buffer Z 5349** from the open BLOB, starting at offset iOffset.)^ 5350** 5351** ^If offset iOffset is less than N bytes from the end of the BLOB, 5352** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 5353** less than zero, [SQLITE_ERROR] is returned and no data is read. 5354** ^The size of the blob (and hence the maximum value of N+iOffset) 5355** can be determined using the [sqlite3_blob_bytes()] interface. 5356** 5357** ^An attempt to read from an expired [BLOB handle] fails with an 5358** error code of [SQLITE_ABORT]. 5359** 5360** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 5361** Otherwise, an [error code] or an [extended error code] is returned.)^ 5362** 5363** This routine only works on a [BLOB handle] which has been created 5364** by a prior successful call to [sqlite3_blob_open()] and which has not 5365** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5366** to this routine results in undefined and probably undesirable behavior. 5367** 5368** See also: [sqlite3_blob_write()]. 5369*/ 5370SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 5371 5372/* 5373** CAPI3REF: Write Data Into A BLOB Incrementally 5374** 5375** ^This function is used to write data into an open [BLOB handle] from a 5376** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 5377** into the open BLOB, starting at offset iOffset. 5378** 5379** ^If the [BLOB handle] passed as the first argument was not opened for 5380** writing (the flags parameter to [sqlite3_blob_open()] was zero), 5381** this function returns [SQLITE_READONLY]. 5382** 5383** ^This function may only modify the contents of the BLOB; it is 5384** not possible to increase the size of a BLOB using this API. 5385** ^If offset iOffset is less than N bytes from the end of the BLOB, 5386** [SQLITE_ERROR] is returned and no data is written. ^If N is 5387** less than zero [SQLITE_ERROR] is returned and no data is written. 5388** The size of the BLOB (and hence the maximum value of N+iOffset) 5389** can be determined using the [sqlite3_blob_bytes()] interface. 5390** 5391** ^An attempt to write to an expired [BLOB handle] fails with an 5392** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 5393** before the [BLOB handle] expired are not rolled back by the 5394** expiration of the handle, though of course those changes might 5395** have been overwritten by the statement that expired the BLOB handle 5396** or by other independent statements. 5397** 5398** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 5399** Otherwise, an [error code] or an [extended error code] is returned.)^ 5400** 5401** This routine only works on a [BLOB handle] which has been created 5402** by a prior successful call to [sqlite3_blob_open()] and which has not 5403** been closed by [sqlite3_blob_close()]. Passing any other pointer in 5404** to this routine results in undefined and probably undesirable behavior. 5405** 5406** See also: [sqlite3_blob_read()]. 5407*/ 5408SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 5409 5410/* 5411** CAPI3REF: Virtual File System Objects 5412** 5413** A virtual filesystem (VFS) is an [sqlite3_vfs] object 5414** that SQLite uses to interact 5415** with the underlying operating system. Most SQLite builds come with a 5416** single default VFS that is appropriate for the host computer. 5417** New VFSes can be registered and existing VFSes can be unregistered. 5418** The following interfaces are provided. 5419** 5420** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 5421** ^Names are case sensitive. 5422** ^Names are zero-terminated UTF-8 strings. 5423** ^If there is no match, a NULL pointer is returned. 5424** ^If zVfsName is NULL then the default VFS is returned. 5425** 5426** ^New VFSes are registered with sqlite3_vfs_register(). 5427** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 5428** ^The same VFS can be registered multiple times without injury. 5429** ^To make an existing VFS into the default VFS, register it again 5430** with the makeDflt flag set. If two different VFSes with the 5431** same name are registered, the behavior is undefined. If a 5432** VFS is registered with a name that is NULL or an empty string, 5433** then the behavior is undefined. 5434** 5435** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 5436** ^(If the default VFS is unregistered, another VFS is chosen as 5437** the default. The choice for the new VFS is arbitrary.)^ 5438*/ 5439SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 5440SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 5441SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*); 5442 5443/* 5444** CAPI3REF: Mutexes 5445** 5446** The SQLite core uses these routines for thread 5447** synchronization. Though they are intended for internal 5448** use by SQLite, code that links against SQLite is 5449** permitted to use any of these routines. 5450** 5451** The SQLite source code contains multiple implementations 5452** of these mutex routines. An appropriate implementation 5453** is selected automatically at compile-time. ^(The following 5454** implementations are available in the SQLite core: 5455** 5456** <ul> 5457** <li> SQLITE_MUTEX_OS2 5458** <li> SQLITE_MUTEX_PTHREADS 5459** <li> SQLITE_MUTEX_W32 5460** <li> SQLITE_MUTEX_NOOP 5461** </ul>)^ 5462** 5463** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 5464** that does no real locking and is appropriate for use in 5465** a single-threaded application. ^The SQLITE_MUTEX_OS2, 5466** SQLITE_MUTEX_PTHREADS, and SQLITE_MUTEX_W32 implementations 5467** are appropriate for use on OS/2, Unix, and Windows. 5468** 5469** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 5470** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 5471** implementation is included with the library. In this case the 5472** application must supply a custom mutex implementation using the 5473** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 5474** before calling sqlite3_initialize() or any other public sqlite3_ 5475** function that calls sqlite3_initialize().)^ 5476** 5477** ^The sqlite3_mutex_alloc() routine allocates a new 5478** mutex and returns a pointer to it. ^If it returns NULL 5479** that means that a mutex could not be allocated. ^SQLite 5480** will unwind its stack and return an error. ^(The argument 5481** to sqlite3_mutex_alloc() is one of these integer constants: 5482** 5483** <ul> 5484** <li> SQLITE_MUTEX_FAST 5485** <li> SQLITE_MUTEX_RECURSIVE 5486** <li> SQLITE_MUTEX_STATIC_MASTER 5487** <li> SQLITE_MUTEX_STATIC_MEM 5488** <li> SQLITE_MUTEX_STATIC_MEM2 5489** <li> SQLITE_MUTEX_STATIC_PRNG 5490** <li> SQLITE_MUTEX_STATIC_LRU 5491** <li> SQLITE_MUTEX_STATIC_LRU2 5492** </ul>)^ 5493** 5494** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 5495** cause sqlite3_mutex_alloc() to create 5496** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 5497** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 5498** The mutex implementation does not need to make a distinction 5499** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 5500** not want to. ^SQLite will only request a recursive mutex in 5501** cases where it really needs one. ^If a faster non-recursive mutex 5502** implementation is available on the host platform, the mutex subsystem 5503** might return such a mutex in response to SQLITE_MUTEX_FAST. 5504** 5505** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 5506** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 5507** a pointer to a static preexisting mutex. ^Six static mutexes are 5508** used by the current version of SQLite. Future versions of SQLite 5509** may add additional static mutexes. Static mutexes are for internal 5510** use by SQLite only. Applications that use SQLite mutexes should 5511** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 5512** SQLITE_MUTEX_RECURSIVE. 5513** 5514** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 5515** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 5516** returns a different mutex on every call. ^But for the static 5517** mutex types, the same mutex is returned on every call that has 5518** the same type number. 5519** 5520** ^The sqlite3_mutex_free() routine deallocates a previously 5521** allocated dynamic mutex. ^SQLite is careful to deallocate every 5522** dynamic mutex that it allocates. The dynamic mutexes must not be in 5523** use when they are deallocated. Attempting to deallocate a static 5524** mutex results in undefined behavior. ^SQLite never deallocates 5525** a static mutex. 5526** 5527** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 5528** to enter a mutex. ^If another thread is already within the mutex, 5529** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 5530** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 5531** upon successful entry. ^(Mutexes created using 5532** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 5533** In such cases the, 5534** mutex must be exited an equal number of times before another thread 5535** can enter.)^ ^(If the same thread tries to enter any other 5536** kind of mutex more than once, the behavior is undefined. 5537** SQLite will never exhibit 5538** such behavior in its own use of mutexes.)^ 5539** 5540** ^(Some systems (for example, Windows 95) do not support the operation 5541** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 5542** will always return SQLITE_BUSY. The SQLite core only ever uses 5543** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 5544** 5545** ^The sqlite3_mutex_leave() routine exits a mutex that was 5546** previously entered by the same thread. ^(The behavior 5547** is undefined if the mutex is not currently entered by the 5548** calling thread or is not currently allocated. SQLite will 5549** never do either.)^ 5550** 5551** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 5552** sqlite3_mutex_leave() is a NULL pointer, then all three routines 5553** behave as no-ops. 5554** 5555** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 5556*/ 5557SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int); 5558SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*); 5559SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*); 5560SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*); 5561SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*); 5562 5563/* 5564** CAPI3REF: Mutex Methods Object 5565** 5566** An instance of this structure defines the low-level routines 5567** used to allocate and use mutexes. 5568** 5569** Usually, the default mutex implementations provided by SQLite are 5570** sufficient, however the user has the option of substituting a custom 5571** implementation for specialized deployments or systems for which SQLite 5572** does not provide a suitable implementation. In this case, the user 5573** creates and populates an instance of this structure to pass 5574** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 5575** Additionally, an instance of this structure can be used as an 5576** output variable when querying the system for the current mutex 5577** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 5578** 5579** ^The xMutexInit method defined by this structure is invoked as 5580** part of system initialization by the sqlite3_initialize() function. 5581** ^The xMutexInit routine is called by SQLite exactly once for each 5582** effective call to [sqlite3_initialize()]. 5583** 5584** ^The xMutexEnd method defined by this structure is invoked as 5585** part of system shutdown by the sqlite3_shutdown() function. The 5586** implementation of this method is expected to release all outstanding 5587** resources obtained by the mutex methods implementation, especially 5588** those obtained by the xMutexInit method. ^The xMutexEnd() 5589** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 5590** 5591** ^(The remaining seven methods defined by this structure (xMutexAlloc, 5592** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 5593** xMutexNotheld) implement the following interfaces (respectively): 5594** 5595** <ul> 5596** <li> [sqlite3_mutex_alloc()] </li> 5597** <li> [sqlite3_mutex_free()] </li> 5598** <li> [sqlite3_mutex_enter()] </li> 5599** <li> [sqlite3_mutex_try()] </li> 5600** <li> [sqlite3_mutex_leave()] </li> 5601** <li> [sqlite3_mutex_held()] </li> 5602** <li> [sqlite3_mutex_notheld()] </li> 5603** </ul>)^ 5604** 5605** The only difference is that the public sqlite3_XXX functions enumerated 5606** above silently ignore any invocations that pass a NULL pointer instead 5607** of a valid mutex handle. The implementations of the methods defined 5608** by this structure are not required to handle this case, the results 5609** of passing a NULL pointer instead of a valid mutex handle are undefined 5610** (i.e. it is acceptable to provide an implementation that segfaults if 5611** it is passed a NULL pointer). 5612** 5613** The xMutexInit() method must be threadsafe. ^It must be harmless to 5614** invoke xMutexInit() multiple times within the same process and without 5615** intervening calls to xMutexEnd(). Second and subsequent calls to 5616** xMutexInit() must be no-ops. 5617** 5618** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 5619** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 5620** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 5621** memory allocation for a fast or recursive mutex. 5622** 5623** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 5624** called, but only if the prior call to xMutexInit returned SQLITE_OK. 5625** If xMutexInit fails in any way, it is expected to clean up after itself 5626** prior to returning. 5627*/ 5628typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 5629struct sqlite3_mutex_methods { 5630 int (*xMutexInit)(void); 5631 int (*xMutexEnd)(void); 5632 sqlite3_mutex *(*xMutexAlloc)(int); 5633 void (*xMutexFree)(sqlite3_mutex *); 5634 void (*xMutexEnter)(sqlite3_mutex *); 5635 int (*xMutexTry)(sqlite3_mutex *); 5636 void (*xMutexLeave)(sqlite3_mutex *); 5637 int (*xMutexHeld)(sqlite3_mutex *); 5638 int (*xMutexNotheld)(sqlite3_mutex *); 5639}; 5640 5641/* 5642** CAPI3REF: Mutex Verification Routines 5643** 5644** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 5645** are intended for use inside assert() statements. ^The SQLite core 5646** never uses these routines except inside an assert() and applications 5647** are advised to follow the lead of the core. ^The SQLite core only 5648** provides implementations for these routines when it is compiled 5649** with the SQLITE_DEBUG flag. ^External mutex implementations 5650** are only required to provide these routines if SQLITE_DEBUG is 5651** defined and if NDEBUG is not defined. 5652** 5653** ^These routines should return true if the mutex in their argument 5654** is held or not held, respectively, by the calling thread. 5655** 5656** ^The implementation is not required to provide versions of these 5657** routines that actually work. If the implementation does not provide working 5658** versions of these routines, it should at least provide stubs that always 5659** return true so that one does not get spurious assertion failures. 5660** 5661** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 5662** the routine should return 1. This seems counter-intuitive since 5663** clearly the mutex cannot be held if it does not exist. But 5664** the reason the mutex does not exist is because the build is not 5665** using mutexes. And we do not want the assert() containing the 5666** call to sqlite3_mutex_held() to fail, so a non-zero return is 5667** the appropriate thing to do. ^The sqlite3_mutex_notheld() 5668** interface should also return 1 when given a NULL pointer. 5669*/ 5670#ifndef NDEBUG 5671SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*); 5672SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*); 5673#endif 5674 5675/* 5676** CAPI3REF: Mutex Types 5677** 5678** The [sqlite3_mutex_alloc()] interface takes a single argument 5679** which is one of these integer constants. 5680** 5681** The set of static mutexes may change from one SQLite release to the 5682** next. Applications that override the built-in mutex logic must be 5683** prepared to accommodate additional static mutexes. 5684*/ 5685#define SQLITE_MUTEX_FAST 0 5686#define SQLITE_MUTEX_RECURSIVE 1 5687#define SQLITE_MUTEX_STATIC_MASTER 2 5688#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 5689#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 5690#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 5691#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 5692#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 5693#define SQLITE_MUTEX_STATIC_LRU2 7 /* NOT USED */ 5694#define SQLITE_MUTEX_STATIC_PMEM 7 /* sqlite3PageMalloc() */ 5695 5696/* 5697** CAPI3REF: Retrieve the mutex for a database connection 5698** 5699** ^This interface returns a pointer the [sqlite3_mutex] object that 5700** serializes access to the [database connection] given in the argument 5701** when the [threading mode] is Serialized. 5702** ^If the [threading mode] is Single-thread or Multi-thread then this 5703** routine returns a NULL pointer. 5704*/ 5705SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 5706 5707/* 5708** CAPI3REF: Low-Level Control Of Database Files 5709** 5710** ^The [sqlite3_file_control()] interface makes a direct call to the 5711** xFileControl method for the [sqlite3_io_methods] object associated 5712** with a particular database identified by the second argument. ^The 5713** name of the database is "main" for the main database or "temp" for the 5714** TEMP database, or the name that appears after the AS keyword for 5715** databases that are added using the [ATTACH] SQL command. 5716** ^A NULL pointer can be used in place of "main" to refer to the 5717** main database file. 5718** ^The third and fourth parameters to this routine 5719** are passed directly through to the second and third parameters of 5720** the xFileControl method. ^The return value of the xFileControl 5721** method becomes the return value of this routine. 5722** 5723** ^The SQLITE_FCNTL_FILE_POINTER value for the op parameter causes 5724** a pointer to the underlying [sqlite3_file] object to be written into 5725** the space pointed to by the 4th parameter. ^The SQLITE_FCNTL_FILE_POINTER 5726** case is a short-circuit path which does not actually invoke the 5727** underlying sqlite3_io_methods.xFileControl method. 5728** 5729** ^If the second parameter (zDbName) does not match the name of any 5730** open database file, then SQLITE_ERROR is returned. ^This error 5731** code is not remembered and will not be recalled by [sqlite3_errcode()] 5732** or [sqlite3_errmsg()]. The underlying xFileControl method might 5733** also return SQLITE_ERROR. There is no way to distinguish between 5734** an incorrect zDbName and an SQLITE_ERROR return from the underlying 5735** xFileControl method. 5736** 5737** See also: [SQLITE_FCNTL_LOCKSTATE] 5738*/ 5739SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 5740 5741/* 5742** CAPI3REF: Testing Interface 5743** 5744** ^The sqlite3_test_control() interface is used to read out internal 5745** state of SQLite and to inject faults into SQLite for testing 5746** purposes. ^The first parameter is an operation code that determines 5747** the number, meaning, and operation of all subsequent parameters. 5748** 5749** This interface is not for use by applications. It exists solely 5750** for verifying the correct operation of the SQLite library. Depending 5751** on how the SQLite library is compiled, this interface might not exist. 5752** 5753** The details of the operation codes, their meanings, the parameters 5754** they take, and what they do are all subject to change without notice. 5755** Unlike most of the SQLite API, this function is not guaranteed to 5756** operate consistently from one release to the next. 5757*/ 5758SQLITE_API int sqlite3_test_control(int op, ...); 5759 5760/* 5761** CAPI3REF: Testing Interface Operation Codes 5762** 5763** These constants are the valid operation code parameters used 5764** as the first argument to [sqlite3_test_control()]. 5765** 5766** These parameters and their meanings are subject to change 5767** without notice. These values are for testing purposes only. 5768** Applications should not use any of these parameters or the 5769** [sqlite3_test_control()] interface. 5770*/ 5771#define SQLITE_TESTCTRL_FIRST 5 5772#define SQLITE_TESTCTRL_PRNG_SAVE 5 5773#define SQLITE_TESTCTRL_PRNG_RESTORE 6 5774#define SQLITE_TESTCTRL_PRNG_RESET 7 5775#define SQLITE_TESTCTRL_BITVEC_TEST 8 5776#define SQLITE_TESTCTRL_FAULT_INSTALL 9 5777#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 5778#define SQLITE_TESTCTRL_PENDING_BYTE 11 5779#define SQLITE_TESTCTRL_ASSERT 12 5780#define SQLITE_TESTCTRL_ALWAYS 13 5781#define SQLITE_TESTCTRL_RESERVE 14 5782#define SQLITE_TESTCTRL_OPTIMIZATIONS 15 5783#define SQLITE_TESTCTRL_ISKEYWORD 16 5784#define SQLITE_TESTCTRL_SCRATCHMALLOC 17 5785#define SQLITE_TESTCTRL_LOCALTIME_FAULT 18 5786#define SQLITE_TESTCTRL_EXPLAIN_STMT 19 5787#define SQLITE_TESTCTRL_LAST 19 5788 5789/* 5790** CAPI3REF: SQLite Runtime Status 5791** 5792** ^This interface is used to retrieve runtime status information 5793** about the performance of SQLite, and optionally to reset various 5794** highwater marks. ^The first argument is an integer code for 5795** the specific parameter to measure. ^(Recognized integer codes 5796** are of the form [status parameters | SQLITE_STATUS_...].)^ 5797** ^The current value of the parameter is returned into *pCurrent. 5798** ^The highest recorded value is returned in *pHighwater. ^If the 5799** resetFlag is true, then the highest record value is reset after 5800** *pHighwater is written. ^(Some parameters do not record the highest 5801** value. For those parameters 5802** nothing is written into *pHighwater and the resetFlag is ignored.)^ 5803** ^(Other parameters record only the highwater mark and not the current 5804** value. For these latter parameters nothing is written into *pCurrent.)^ 5805** 5806** ^The sqlite3_status() routine returns SQLITE_OK on success and a 5807** non-zero [error code] on failure. 5808** 5809** This routine is threadsafe but is not atomic. This routine can be 5810** called while other threads are running the same or different SQLite 5811** interfaces. However the values returned in *pCurrent and 5812** *pHighwater reflect the status of SQLite at different points in time 5813** and it is possible that another thread might change the parameter 5814** in between the times when *pCurrent and *pHighwater are written. 5815** 5816** See also: [sqlite3_db_status()] 5817*/ 5818SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 5819 5820 5821/* 5822** CAPI3REF: Status Parameters 5823** KEYWORDS: {status parameters} 5824** 5825** These integer constants designate various run-time status parameters 5826** that can be returned by [sqlite3_status()]. 5827** 5828** <dl> 5829** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 5830** <dd>This parameter is the current amount of memory checked out 5831** using [sqlite3_malloc()], either directly or indirectly. The 5832** figure includes calls made to [sqlite3_malloc()] by the application 5833** and internal memory usage by the SQLite library. Scratch memory 5834** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 5835** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 5836** this parameter. The amount returned is the sum of the allocation 5837** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 5838** 5839** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 5840** <dd>This parameter records the largest memory allocation request 5841** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 5842** internal equivalents). Only the value returned in the 5843** *pHighwater parameter to [sqlite3_status()] is of interest. 5844** The value written into the *pCurrent parameter is undefined.</dd>)^ 5845** 5846** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt> 5847** <dd>This parameter records the number of separate memory allocations 5848** currently checked out.</dd>)^ 5849** 5850** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 5851** <dd>This parameter returns the number of pages used out of the 5852** [pagecache memory allocator] that was configured using 5853** [SQLITE_CONFIG_PAGECACHE]. The 5854** value returned is in pages, not in bytes.</dd>)^ 5855** 5856** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 5857** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5858** <dd>This parameter returns the number of bytes of page cache 5859** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE] 5860** buffer and where forced to overflow to [sqlite3_malloc()]. The 5861** returned value includes allocations that overflowed because they 5862** where too large (they were larger than the "sz" parameter to 5863** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5864** no space was left in the page cache.</dd>)^ 5865** 5866** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5867** <dd>This parameter records the largest memory allocation request 5868** handed to [pagecache memory allocator]. Only the value returned in the 5869** *pHighwater parameter to [sqlite3_status()] is of interest. 5870** The value written into the *pCurrent parameter is undefined.</dd>)^ 5871** 5872** [[SQLITE_STATUS_SCRATCH_USED]] ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5873** <dd>This parameter returns the number of allocations used out of the 5874** [scratch memory allocator] configured using 5875** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5876** in bytes. Since a single thread may only have one scratch allocation 5877** outstanding at time, this parameter also reports the number of threads 5878** using scratch memory at the same time.</dd>)^ 5879** 5880** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5881** <dd>This parameter returns the number of bytes of scratch memory 5882** allocation which could not be satisfied by the [SQLITE_CONFIG_SCRATCH] 5883** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5884** returned include overflows because the requested allocation was too 5885** larger (that is, because the requested allocation was larger than the 5886** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5887** slots were available. 5888** </dd>)^ 5889** 5890** [[SQLITE_STATUS_SCRATCH_SIZE]] ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5891** <dd>This parameter records the largest memory allocation request 5892** handed to [scratch memory allocator]. Only the value returned in the 5893** *pHighwater parameter to [sqlite3_status()] is of interest. 5894** The value written into the *pCurrent parameter is undefined.</dd>)^ 5895** 5896** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5897** <dd>This parameter records the deepest parser stack. It is only 5898** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5899** </dl> 5900** 5901** New status parameters may be added from time to time. 5902*/ 5903#define SQLITE_STATUS_MEMORY_USED 0 5904#define SQLITE_STATUS_PAGECACHE_USED 1 5905#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5906#define SQLITE_STATUS_SCRATCH_USED 3 5907#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5908#define SQLITE_STATUS_MALLOC_SIZE 5 5909#define SQLITE_STATUS_PARSER_STACK 6 5910#define SQLITE_STATUS_PAGECACHE_SIZE 7 5911#define SQLITE_STATUS_SCRATCH_SIZE 8 5912#define SQLITE_STATUS_MALLOC_COUNT 9 5913 5914/* 5915** CAPI3REF: Database Connection Status 5916** 5917** ^This interface is used to retrieve runtime status information 5918** about a single [database connection]. ^The first argument is the 5919** database connection object to be interrogated. ^The second argument 5920** is an integer constant, taken from the set of 5921** [SQLITE_DBSTATUS options], that 5922** determines the parameter to interrogate. The set of 5923** [SQLITE_DBSTATUS options] is likely 5924** to grow in future releases of SQLite. 5925** 5926** ^The current value of the requested parameter is written into *pCur 5927** and the highest instantaneous value is written into *pHiwtr. ^If 5928** the resetFlg is true, then the highest instantaneous value is 5929** reset back down to the current value. 5930** 5931** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 5932** non-zero [error code] on failure. 5933** 5934** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5935*/ 5936SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5937 5938/* 5939** CAPI3REF: Status Parameters for database connections 5940** KEYWORDS: {SQLITE_DBSTATUS options} 5941** 5942** These constants are the available integer "verbs" that can be passed as 5943** the second argument to the [sqlite3_db_status()] interface. 5944** 5945** New verbs may be added in future releases of SQLite. Existing verbs 5946** might be discontinued. Applications should check the return code from 5947** [sqlite3_db_status()] to make sure that the call worked. 5948** The [sqlite3_db_status()] interface will return a non-zero error code 5949** if a discontinued or unsupported verb is invoked. 5950** 5951** <dl> 5952** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5953** <dd>This parameter returns the number of lookaside memory slots currently 5954** checked out.</dd>)^ 5955** 5956** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt> 5957** <dd>This parameter returns the number malloc attempts that were 5958** satisfied using lookaside memory. Only the high-water value is meaningful; 5959** the current value is always zero.)^ 5960** 5961** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]] 5962** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt> 5963** <dd>This parameter returns the number malloc attempts that might have 5964** been satisfied using lookaside memory but failed due to the amount of 5965** memory requested being larger than the lookaside slot size. 5966** Only the high-water value is meaningful; 5967** the current value is always zero.)^ 5968** 5969** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]] 5970** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt> 5971** <dd>This parameter returns the number malloc attempts that might have 5972** been satisfied using lookaside memory but failed due to all lookaside 5973** memory already being in use. 5974** Only the high-water value is meaningful; 5975** the current value is always zero.)^ 5976** 5977** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt> 5978** <dd>This parameter returns the approximate number of of bytes of heap 5979** memory used by all pager caches associated with the database connection.)^ 5980** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0. 5981** 5982** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt> 5983** <dd>This parameter returns the approximate number of of bytes of heap 5984** memory used to store the schema for all databases associated 5985** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 5986** ^The full amount of memory used by the schemas is reported, even if the 5987** schema memory is shared with other database connections due to 5988** [shared cache mode] being enabled. 5989** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0. 5990** 5991** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt> 5992** <dd>This parameter returns the approximate number of of bytes of heap 5993** and lookaside memory used by all prepared statements associated with 5994** the database connection.)^ 5995** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0. 5996** </dd> 5997** 5998** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt> 5999** <dd>This parameter returns the number of pager cache hits that have 6000** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 6001** is always 0. 6002** </dd> 6003** 6004** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt> 6005** <dd>This parameter returns the number of pager cache misses that have 6006** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 6007** is always 0. 6008** </dd> 6009** </dl> 6010*/ 6011#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 6012#define SQLITE_DBSTATUS_CACHE_USED 1 6013#define SQLITE_DBSTATUS_SCHEMA_USED 2 6014#define SQLITE_DBSTATUS_STMT_USED 3 6015#define SQLITE_DBSTATUS_LOOKASIDE_HIT 4 6016#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE 5 6017#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL 6 6018#define SQLITE_DBSTATUS_CACHE_HIT 7 6019#define SQLITE_DBSTATUS_CACHE_MISS 8 6020#define SQLITE_DBSTATUS_MAX 8 /* Largest defined DBSTATUS */ 6021 6022 6023/* 6024** CAPI3REF: Prepared Statement Status 6025** 6026** ^(Each prepared statement maintains various 6027** [SQLITE_STMTSTATUS counters] that measure the number 6028** of times it has performed specific operations.)^ These counters can 6029** be used to monitor the performance characteristics of the prepared 6030** statements. For example, if the number of table steps greatly exceeds 6031** the number of table searches or result rows, that would tend to indicate 6032** that the prepared statement is using a full table scan rather than 6033** an index. 6034** 6035** ^(This interface is used to retrieve and reset counter values from 6036** a [prepared statement]. The first argument is the prepared statement 6037** object to be interrogated. The second argument 6038** is an integer code for a specific [SQLITE_STMTSTATUS counter] 6039** to be interrogated.)^ 6040** ^The current value of the requested counter is returned. 6041** ^If the resetFlg is true, then the counter is reset to zero after this 6042** interface call returns. 6043** 6044** See also: [sqlite3_status()] and [sqlite3_db_status()]. 6045*/ 6046SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 6047 6048/* 6049** CAPI3REF: Status Parameters for prepared statements 6050** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters} 6051** 6052** These preprocessor macros define integer codes that name counter 6053** values associated with the [sqlite3_stmt_status()] interface. 6054** The meanings of the various counters are as follows: 6055** 6056** <dl> 6057** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 6058** <dd>^This is the number of times that SQLite has stepped forward in 6059** a table as part of a full table scan. Large numbers for this counter 6060** may indicate opportunities for performance improvement through 6061** careful use of indices.</dd> 6062** 6063** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt> 6064** <dd>^This is the number of sort operations that have occurred. 6065** A non-zero value in this counter may indicate an opportunity to 6066** improvement performance through careful use of indices.</dd> 6067** 6068** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt> 6069** <dd>^This is the number of rows inserted into transient indices that 6070** were created automatically in order to help joins run faster. 6071** A non-zero value in this counter may indicate an opportunity to 6072** improvement performance by adding permanent indices that do not 6073** need to be reinitialized each time the statement is run.</dd> 6074** </dl> 6075*/ 6076#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 6077#define SQLITE_STMTSTATUS_SORT 2 6078#define SQLITE_STMTSTATUS_AUTOINDEX 3 6079 6080/* 6081** CAPI3REF: Custom Page Cache Object 6082** 6083** The sqlite3_pcache type is opaque. It is implemented by 6084** the pluggable module. The SQLite core has no knowledge of 6085** its size or internal structure and never deals with the 6086** sqlite3_pcache object except by holding and passing pointers 6087** to the object. 6088** 6089** See [sqlite3_pcache_methods2] for additional information. 6090*/ 6091typedef struct sqlite3_pcache sqlite3_pcache; 6092 6093/* 6094** CAPI3REF: Custom Page Cache Object 6095** 6096** The sqlite3_pcache_page object represents a single page in the 6097** page cache. The page cache will allocate instances of this 6098** object. Various methods of the page cache use pointers to instances 6099** of this object as parameters or as their return value. 6100** 6101** See [sqlite3_pcache_methods2] for additional information. 6102*/ 6103typedef struct sqlite3_pcache_page sqlite3_pcache_page; 6104struct sqlite3_pcache_page { 6105 void *pBuf; /* The content of the page */ 6106 void *pExtra; /* Extra information associated with the page */ 6107}; 6108 6109/* 6110** CAPI3REF: Application Defined Page Cache. 6111** KEYWORDS: {page cache} 6112** 6113** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can 6114** register an alternative page cache implementation by passing in an 6115** instance of the sqlite3_pcache_methods2 structure.)^ 6116** In many applications, most of the heap memory allocated by 6117** SQLite is used for the page cache. 6118** By implementing a 6119** custom page cache using this API, an application can better control 6120** the amount of memory consumed by SQLite, the way in which 6121** that memory is allocated and released, and the policies used to 6122** determine exactly which parts of a database file are cached and for 6123** how long. 6124** 6125** The alternative page cache mechanism is an 6126** extreme measure that is only needed by the most demanding applications. 6127** The built-in page cache is recommended for most uses. 6128** 6129** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an 6130** internal buffer by SQLite within the call to [sqlite3_config]. Hence 6131** the application may discard the parameter after the call to 6132** [sqlite3_config()] returns.)^ 6133** 6134** [[the xInit() page cache method]] 6135** ^(The xInit() method is called once for each effective 6136** call to [sqlite3_initialize()])^ 6137** (usually only once during the lifetime of the process). ^(The xInit() 6138** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^ 6139** The intent of the xInit() method is to set up global data structures 6140** required by the custom page cache implementation. 6141** ^(If the xInit() method is NULL, then the 6142** built-in default page cache is used instead of the application defined 6143** page cache.)^ 6144** 6145** [[the xShutdown() page cache method]] 6146** ^The xShutdown() method is called by [sqlite3_shutdown()]. 6147** It can be used to clean up 6148** any outstanding resources before process shutdown, if required. 6149** ^The xShutdown() method may be NULL. 6150** 6151** ^SQLite automatically serializes calls to the xInit method, 6152** so the xInit method need not be threadsafe. ^The 6153** xShutdown method is only called from [sqlite3_shutdown()] so it does 6154** not need to be threadsafe either. All other methods must be threadsafe 6155** in multithreaded applications. 6156** 6157** ^SQLite will never invoke xInit() more than once without an intervening 6158** call to xShutdown(). 6159** 6160** [[the xCreate() page cache methods]] 6161** ^SQLite invokes the xCreate() method to construct a new cache instance. 6162** SQLite will typically create one cache instance for each open database file, 6163** though this is not guaranteed. ^The 6164** first parameter, szPage, is the size in bytes of the pages that must 6165** be allocated by the cache. ^szPage will always a power of two. ^The 6166** second parameter szExtra is a number of bytes of extra storage 6167** associated with each page cache entry. ^The szExtra parameter will 6168** a number less than 250. SQLite will use the 6169** extra szExtra bytes on each page to store metadata about the underlying 6170** database page on disk. The value passed into szExtra depends 6171** on the SQLite version, the target platform, and how SQLite was compiled. 6172** ^The third argument to xCreate(), bPurgeable, is true if the cache being 6173** created will be used to cache database pages of a file stored on disk, or 6174** false if it is used for an in-memory database. The cache implementation 6175** does not have to do anything special based with the value of bPurgeable; 6176** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 6177** never invoke xUnpin() except to deliberately delete a page. 6178** ^In other words, calls to xUnpin() on a cache with bPurgeable set to 6179** false will always have the "discard" flag set to true. 6180** ^Hence, a cache created with bPurgeable false will 6181** never contain any unpinned pages. 6182** 6183** [[the xCachesize() page cache method]] 6184** ^(The xCachesize() method may be called at any time by SQLite to set the 6185** suggested maximum cache-size (number of pages stored by) the cache 6186** instance passed as the first argument. This is the value configured using 6187** the SQLite "[PRAGMA cache_size]" command.)^ As with the bPurgeable 6188** parameter, the implementation is not required to do anything with this 6189** value; it is advisory only. 6190** 6191** [[the xPagecount() page cache methods]] 6192** The xPagecount() method must return the number of pages currently 6193** stored in the cache, both pinned and unpinned. 6194** 6195** [[the xFetch() page cache methods]] 6196** The xFetch() method locates a page in the cache and returns a pointer to 6197** an sqlite3_pcache_page object associated with that page, or a NULL pointer. 6198** The pBuf element of the returned sqlite3_pcache_page object will be a 6199** pointer to a buffer of szPage bytes used to store the content of a 6200** single database page. The pExtra element of sqlite3_pcache_page will be 6201** a pointer to the szExtra bytes of extra storage that SQLite has requested 6202** for each entry in the page cache. 6203** 6204** The page to be fetched is determined by the key. ^The minimum key value 6205** is 1. After it has been retrieved using xFetch, the page is considered 6206** to be "pinned". 6207** 6208** If the requested page is already in the page cache, then the page cache 6209** implementation must return a pointer to the page buffer with its content 6210** intact. If the requested page is not already in the cache, then the 6211** cache implementation should use the value of the createFlag 6212** parameter to help it determined what action to take: 6213** 6214** <table border=1 width=85% align=center> 6215** <tr><th> createFlag <th> Behaviour when page is not already in cache 6216** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 6217** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 6218** Otherwise return NULL. 6219** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 6220** NULL if allocating a new page is effectively impossible. 6221** </table> 6222** 6223** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1. SQLite 6224** will only use a createFlag of 2 after a prior call with a createFlag of 1 6225** failed.)^ In between the to xFetch() calls, SQLite may 6226** attempt to unpin one or more cache pages by spilling the content of 6227** pinned pages to disk and synching the operating system disk cache. 6228** 6229** [[the xUnpin() page cache method]] 6230** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 6231** as its second argument. If the third parameter, discard, is non-zero, 6232** then the page must be evicted from the cache. 6233** ^If the discard parameter is 6234** zero, then the page may be discarded or retained at the discretion of 6235** page cache implementation. ^The page cache implementation 6236** may choose to evict unpinned pages at any time. 6237** 6238** The cache must not perform any reference counting. A single 6239** call to xUnpin() unpins the page regardless of the number of prior calls 6240** to xFetch(). 6241** 6242** [[the xRekey() page cache methods]] 6243** The xRekey() method is used to change the key value associated with the 6244** page passed as the second argument. If the cache 6245** previously contains an entry associated with newKey, it must be 6246** discarded. ^Any prior cache entry associated with newKey is guaranteed not 6247** to be pinned. 6248** 6249** When SQLite calls the xTruncate() method, the cache must discard all 6250** existing cache entries with page numbers (keys) greater than or equal 6251** to the value of the iLimit parameter passed to xTruncate(). If any 6252** of these pages are pinned, they are implicitly unpinned, meaning that 6253** they can be safely discarded. 6254** 6255** [[the xDestroy() page cache method]] 6256** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 6257** All resources associated with the specified cache should be freed. ^After 6258** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 6259** handle invalid, and will not use it with any other sqlite3_pcache_methods2 6260** functions. 6261** 6262** [[the xShrink() page cache method]] 6263** ^SQLite invokes the xShrink() method when it wants the page cache to 6264** free up as much of heap memory as possible. The page cache implementation 6265** is not obligated to free any memory, but well-behaved implementations should 6266** do their best. 6267*/ 6268typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2; 6269struct sqlite3_pcache_methods2 { 6270 int iVersion; 6271 void *pArg; 6272 int (*xInit)(void*); 6273 void (*xShutdown)(void*); 6274 sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable); 6275 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6276 int (*xPagecount)(sqlite3_pcache*); 6277 sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6278 void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard); 6279 void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 6280 unsigned oldKey, unsigned newKey); 6281 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6282 void (*xDestroy)(sqlite3_pcache*); 6283 void (*xShrink)(sqlite3_pcache*); 6284}; 6285 6286/* 6287** This is the obsolete pcache_methods object that has now been replaced 6288** by sqlite3_pcache_methods2. This object is not used by SQLite. It is 6289** retained in the header file for backwards compatibility only. 6290*/ 6291typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 6292struct sqlite3_pcache_methods { 6293 void *pArg; 6294 int (*xInit)(void*); 6295 void (*xShutdown)(void*); 6296 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 6297 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 6298 int (*xPagecount)(sqlite3_pcache*); 6299 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 6300 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 6301 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 6302 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 6303 void (*xDestroy)(sqlite3_pcache*); 6304}; 6305 6306 6307/* 6308** CAPI3REF: Online Backup Object 6309** 6310** The sqlite3_backup object records state information about an ongoing 6311** online backup operation. ^The sqlite3_backup object is created by 6312** a call to [sqlite3_backup_init()] and is destroyed by a call to 6313** [sqlite3_backup_finish()]. 6314** 6315** See Also: [Using the SQLite Online Backup API] 6316*/ 6317typedef struct sqlite3_backup sqlite3_backup; 6318 6319/* 6320** CAPI3REF: Online Backup API. 6321** 6322** The backup API copies the content of one database into another. 6323** It is useful either for creating backups of databases or 6324** for copying in-memory databases to or from persistent files. 6325** 6326** See Also: [Using the SQLite Online Backup API] 6327** 6328** ^SQLite holds a write transaction open on the destination database file 6329** for the duration of the backup operation. 6330** ^The source database is read-locked only while it is being read; 6331** it is not locked continuously for the entire backup operation. 6332** ^Thus, the backup may be performed on a live source database without 6333** preventing other database connections from 6334** reading or writing to the source database while the backup is underway. 6335** 6336** ^(To perform a backup operation: 6337** <ol> 6338** <li><b>sqlite3_backup_init()</b> is called once to initialize the 6339** backup, 6340** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 6341** the data between the two databases, and finally 6342** <li><b>sqlite3_backup_finish()</b> is called to release all resources 6343** associated with the backup operation. 6344** </ol>)^ 6345** There should be exactly one call to sqlite3_backup_finish() for each 6346** successful call to sqlite3_backup_init(). 6347** 6348** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b> 6349** 6350** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 6351** [database connection] associated with the destination database 6352** and the database name, respectively. 6353** ^The database name is "main" for the main database, "temp" for the 6354** temporary database, or the name specified after the AS keyword in 6355** an [ATTACH] statement for an attached database. 6356** ^The S and M arguments passed to 6357** sqlite3_backup_init(D,N,S,M) identify the [database connection] 6358** and database name of the source database, respectively. 6359** ^The source and destination [database connections] (parameters S and D) 6360** must be different or else sqlite3_backup_init(D,N,S,M) will fail with 6361** an error. 6362** 6363** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 6364** returned and an error code and error message are stored in the 6365** destination [database connection] D. 6366** ^The error code and message for the failed call to sqlite3_backup_init() 6367** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 6368** [sqlite3_errmsg16()] functions. 6369** ^A successful call to sqlite3_backup_init() returns a pointer to an 6370** [sqlite3_backup] object. 6371** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 6372** sqlite3_backup_finish() functions to perform the specified backup 6373** operation. 6374** 6375** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b> 6376** 6377** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 6378** the source and destination databases specified by [sqlite3_backup] object B. 6379** ^If N is negative, all remaining source pages are copied. 6380** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 6381** are still more pages to be copied, then the function returns [SQLITE_OK]. 6382** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 6383** from source to destination, then it returns [SQLITE_DONE]. 6384** ^If an error occurs while running sqlite3_backup_step(B,N), 6385** then an [error code] is returned. ^As well as [SQLITE_OK] and 6386** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 6387** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 6388** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 6389** 6390** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if 6391** <ol> 6392** <li> the destination database was opened read-only, or 6393** <li> the destination database is using write-ahead-log journaling 6394** and the destination and source page sizes differ, or 6395** <li> the destination database is an in-memory database and the 6396** destination and source page sizes differ. 6397** </ol>)^ 6398** 6399** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 6400** the [sqlite3_busy_handler | busy-handler function] 6401** is invoked (if one is specified). ^If the 6402** busy-handler returns non-zero before the lock is available, then 6403** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 6404** sqlite3_backup_step() can be retried later. ^If the source 6405** [database connection] 6406** is being used to write to the source database when sqlite3_backup_step() 6407** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 6408** case the call to sqlite3_backup_step() can be retried later on. ^(If 6409** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 6410** [SQLITE_READONLY] is returned, then 6411** there is no point in retrying the call to sqlite3_backup_step(). These 6412** errors are considered fatal.)^ The application must accept 6413** that the backup operation has failed and pass the backup operation handle 6414** to the sqlite3_backup_finish() to release associated resources. 6415** 6416** ^The first call to sqlite3_backup_step() obtains an exclusive lock 6417** on the destination file. ^The exclusive lock is not released until either 6418** sqlite3_backup_finish() is called or the backup operation is complete 6419** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 6420** sqlite3_backup_step() obtains a [shared lock] on the source database that 6421** lasts for the duration of the sqlite3_backup_step() call. 6422** ^Because the source database is not locked between calls to 6423** sqlite3_backup_step(), the source database may be modified mid-way 6424** through the backup process. ^If the source database is modified by an 6425** external process or via a database connection other than the one being 6426** used by the backup operation, then the backup will be automatically 6427** restarted by the next call to sqlite3_backup_step(). ^If the source 6428** database is modified by the using the same database connection as is used 6429** by the backup operation, then the backup database is automatically 6430** updated at the same time. 6431** 6432** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b> 6433** 6434** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 6435** application wishes to abandon the backup operation, the application 6436** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 6437** ^The sqlite3_backup_finish() interfaces releases all 6438** resources associated with the [sqlite3_backup] object. 6439** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 6440** active write-transaction on the destination database is rolled back. 6441** The [sqlite3_backup] object is invalid 6442** and may not be used following a call to sqlite3_backup_finish(). 6443** 6444** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 6445** sqlite3_backup_step() errors occurred, regardless or whether or not 6446** sqlite3_backup_step() completed. 6447** ^If an out-of-memory condition or IO error occurred during any prior 6448** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 6449** sqlite3_backup_finish() returns the corresponding [error code]. 6450** 6451** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 6452** is not a permanent error and does not affect the return value of 6453** sqlite3_backup_finish(). 6454** 6455** [[sqlite3_backup__remaining()]] [[sqlite3_backup_pagecount()]] 6456** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b> 6457** 6458** ^Each call to sqlite3_backup_step() sets two values inside 6459** the [sqlite3_backup] object: the number of pages still to be backed 6460** up and the total number of pages in the source database file. 6461** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 6462** retrieve these two values, respectively. 6463** 6464** ^The values returned by these functions are only updated by 6465** sqlite3_backup_step(). ^If the source database is modified during a backup 6466** operation, then the values are not updated to account for any extra 6467** pages that need to be updated or the size of the source database file 6468** changing. 6469** 6470** <b>Concurrent Usage of Database Handles</b> 6471** 6472** ^The source [database connection] may be used by the application for other 6473** purposes while a backup operation is underway or being initialized. 6474** ^If SQLite is compiled and configured to support threadsafe database 6475** connections, then the source database connection may be used concurrently 6476** from within other threads. 6477** 6478** However, the application must guarantee that the destination 6479** [database connection] is not passed to any other API (by any thread) after 6480** sqlite3_backup_init() is called and before the corresponding call to 6481** sqlite3_backup_finish(). SQLite does not currently check to see 6482** if the application incorrectly accesses the destination [database connection] 6483** and so no error code is reported, but the operations may malfunction 6484** nevertheless. Use of the destination database connection while a 6485** backup is in progress might also also cause a mutex deadlock. 6486** 6487** If running in [shared cache mode], the application must 6488** guarantee that the shared cache used by the destination database 6489** is not accessed while the backup is running. In practice this means 6490** that the application must guarantee that the disk file being 6491** backed up to is not accessed by any connection within the process, 6492** not just the specific connection that was passed to sqlite3_backup_init(). 6493** 6494** The [sqlite3_backup] object itself is partially threadsafe. Multiple 6495** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 6496** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 6497** APIs are not strictly speaking threadsafe. If they are invoked at the 6498** same time as another thread is invoking sqlite3_backup_step() it is 6499** possible that they return invalid values. 6500*/ 6501SQLITE_API sqlite3_backup *sqlite3_backup_init( 6502 sqlite3 *pDest, /* Destination database handle */ 6503 const char *zDestName, /* Destination database name */ 6504 sqlite3 *pSource, /* Source database handle */ 6505 const char *zSourceName /* Source database name */ 6506); 6507SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage); 6508SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p); 6509SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p); 6510SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p); 6511 6512/* 6513** CAPI3REF: Unlock Notification 6514** 6515** ^When running in shared-cache mode, a database operation may fail with 6516** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 6517** individual tables within the shared-cache cannot be obtained. See 6518** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 6519** ^This API may be used to register a callback that SQLite will invoke 6520** when the connection currently holding the required lock relinquishes it. 6521** ^This API is only available if the library was compiled with the 6522** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 6523** 6524** See Also: [Using the SQLite Unlock Notification Feature]. 6525** 6526** ^Shared-cache locks are released when a database connection concludes 6527** its current transaction, either by committing it or rolling it back. 6528** 6529** ^When a connection (known as the blocked connection) fails to obtain a 6530** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 6531** identity of the database connection (the blocking connection) that 6532** has locked the required resource is stored internally. ^After an 6533** application receives an SQLITE_LOCKED error, it may call the 6534** sqlite3_unlock_notify() method with the blocked connection handle as 6535** the first argument to register for a callback that will be invoked 6536** when the blocking connections current transaction is concluded. ^The 6537** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 6538** call that concludes the blocking connections transaction. 6539** 6540** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 6541** there is a chance that the blocking connection will have already 6542** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 6543** If this happens, then the specified callback is invoked immediately, 6544** from within the call to sqlite3_unlock_notify().)^ 6545** 6546** ^If the blocked connection is attempting to obtain a write-lock on a 6547** shared-cache table, and more than one other connection currently holds 6548** a read-lock on the same table, then SQLite arbitrarily selects one of 6549** the other connections to use as the blocking connection. 6550** 6551** ^(There may be at most one unlock-notify callback registered by a 6552** blocked connection. If sqlite3_unlock_notify() is called when the 6553** blocked connection already has a registered unlock-notify callback, 6554** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 6555** called with a NULL pointer as its second argument, then any existing 6556** unlock-notify callback is canceled. ^The blocked connections 6557** unlock-notify callback may also be canceled by closing the blocked 6558** connection using [sqlite3_close()]. 6559** 6560** The unlock-notify callback is not reentrant. If an application invokes 6561** any sqlite3_xxx API functions from within an unlock-notify callback, a 6562** crash or deadlock may be the result. 6563** 6564** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 6565** returns SQLITE_OK. 6566** 6567** <b>Callback Invocation Details</b> 6568** 6569** When an unlock-notify callback is registered, the application provides a 6570** single void* pointer that is passed to the callback when it is invoked. 6571** However, the signature of the callback function allows SQLite to pass 6572** it an array of void* context pointers. The first argument passed to 6573** an unlock-notify callback is a pointer to an array of void* pointers, 6574** and the second is the number of entries in the array. 6575** 6576** When a blocking connections transaction is concluded, there may be 6577** more than one blocked connection that has registered for an unlock-notify 6578** callback. ^If two or more such blocked connections have specified the 6579** same callback function, then instead of invoking the callback function 6580** multiple times, it is invoked once with the set of void* context pointers 6581** specified by the blocked connections bundled together into an array. 6582** This gives the application an opportunity to prioritize any actions 6583** related to the set of unblocked database connections. 6584** 6585** <b>Deadlock Detection</b> 6586** 6587** Assuming that after registering for an unlock-notify callback a 6588** database waits for the callback to be issued before taking any further 6589** action (a reasonable assumption), then using this API may cause the 6590** application to deadlock. For example, if connection X is waiting for 6591** connection Y's transaction to be concluded, and similarly connection 6592** Y is waiting on connection X's transaction, then neither connection 6593** will proceed and the system may remain deadlocked indefinitely. 6594** 6595** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 6596** detection. ^If a given call to sqlite3_unlock_notify() would put the 6597** system in a deadlocked state, then SQLITE_LOCKED is returned and no 6598** unlock-notify callback is registered. The system is said to be in 6599** a deadlocked state if connection A has registered for an unlock-notify 6600** callback on the conclusion of connection B's transaction, and connection 6601** B has itself registered for an unlock-notify callback when connection 6602** A's transaction is concluded. ^Indirect deadlock is also detected, so 6603** the system is also considered to be deadlocked if connection B has 6604** registered for an unlock-notify callback on the conclusion of connection 6605** C's transaction, where connection C is waiting on connection A. ^Any 6606** number of levels of indirection are allowed. 6607** 6608** <b>The "DROP TABLE" Exception</b> 6609** 6610** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 6611** always appropriate to call sqlite3_unlock_notify(). There is however, 6612** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 6613** SQLite checks if there are any currently executing SELECT statements 6614** that belong to the same connection. If there are, SQLITE_LOCKED is 6615** returned. In this case there is no "blocking connection", so invoking 6616** sqlite3_unlock_notify() results in the unlock-notify callback being 6617** invoked immediately. If the application then re-attempts the "DROP TABLE" 6618** or "DROP INDEX" query, an infinite loop might be the result. 6619** 6620** One way around this problem is to check the extended error code returned 6621** by an sqlite3_step() call. ^(If there is a blocking connection, then the 6622** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 6623** the special "DROP TABLE/INDEX" case, the extended error code is just 6624** SQLITE_LOCKED.)^ 6625*/ 6626SQLITE_API int sqlite3_unlock_notify( 6627 sqlite3 *pBlocked, /* Waiting connection */ 6628 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 6629 void *pNotifyArg /* Argument to pass to xNotify */ 6630); 6631 6632 6633/* 6634** CAPI3REF: String Comparison 6635** 6636** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications 6637** and extensions to compare the contents of two buffers containing UTF-8 6638** strings in a case-independent fashion, using the same definition of "case 6639** independence" that SQLite uses internally when comparing identifiers. 6640*/ 6641SQLITE_API int sqlite3_stricmp(const char *, const char *); 6642SQLITE_API int sqlite3_strnicmp(const char *, const char *, int); 6643 6644/* 6645** CAPI3REF: Error Logging Interface 6646** 6647** ^The [sqlite3_log()] interface writes a message into the error log 6648** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()]. 6649** ^If logging is enabled, the zFormat string and subsequent arguments are 6650** used with [sqlite3_snprintf()] to generate the final output string. 6651** 6652** The sqlite3_log() interface is intended for use by extensions such as 6653** virtual tables, collating functions, and SQL functions. While there is 6654** nothing to prevent an application from calling sqlite3_log(), doing so 6655** is considered bad form. 6656** 6657** The zFormat string must not be NULL. 6658** 6659** To avoid deadlocks and other threading problems, the sqlite3_log() routine 6660** will not use dynamically allocated memory. The log message is stored in 6661** a fixed-length buffer on the stack. If the log message is longer than 6662** a few hundred characters, it will be truncated to the length of the 6663** buffer. 6664*/ 6665SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...); 6666 6667/* 6668** CAPI3REF: Write-Ahead Log Commit Hook 6669** 6670** ^The [sqlite3_wal_hook()] function is used to register a callback that 6671** will be invoked each time a database connection commits data to a 6672** [write-ahead log] (i.e. whenever a transaction is committed in 6673** [journal_mode | journal_mode=WAL mode]). 6674** 6675** ^The callback is invoked by SQLite after the commit has taken place and 6676** the associated write-lock on the database released, so the implementation 6677** may read, write or [checkpoint] the database as required. 6678** 6679** ^The first parameter passed to the callback function when it is invoked 6680** is a copy of the third parameter passed to sqlite3_wal_hook() when 6681** registering the callback. ^The second is a copy of the database handle. 6682** ^The third parameter is the name of the database that was written to - 6683** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter 6684** is the number of pages currently in the write-ahead log file, 6685** including those that were just committed. 6686** 6687** The callback function should normally return [SQLITE_OK]. ^If an error 6688** code is returned, that error will propagate back up through the 6689** SQLite code base to cause the statement that provoked the callback 6690** to report an error, though the commit will have still occurred. If the 6691** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value 6692** that does not correspond to any valid SQLite error code, the results 6693** are undefined. 6694** 6695** A single database handle may have at most a single write-ahead log callback 6696** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any 6697** previously registered write-ahead log callback. ^Note that the 6698** [sqlite3_wal_autocheckpoint()] interface and the 6699** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will 6700** those overwrite any prior [sqlite3_wal_hook()] settings. 6701*/ 6702SQLITE_API void *sqlite3_wal_hook( 6703 sqlite3*, 6704 int(*)(void *,sqlite3*,const char*,int), 6705 void* 6706); 6707 6708/* 6709** CAPI3REF: Configure an auto-checkpoint 6710** 6711** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around 6712** [sqlite3_wal_hook()] that causes any database on [database connection] D 6713** to automatically [checkpoint] 6714** after committing a transaction if there are N or 6715** more frames in the [write-ahead log] file. ^Passing zero or 6716** a negative value as the nFrame parameter disables automatic 6717** checkpoints entirely. 6718** 6719** ^The callback registered by this function replaces any existing callback 6720** registered using [sqlite3_wal_hook()]. ^Likewise, registering a callback 6721** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism 6722** configured by this function. 6723** 6724** ^The [wal_autocheckpoint pragma] can be used to invoke this interface 6725** from SQL. 6726** 6727** ^Every new [database connection] defaults to having the auto-checkpoint 6728** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT] 6729** pages. The use of this interface 6730** is only necessary if the default setting is found to be suboptimal 6731** for a particular application. 6732*/ 6733SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N); 6734 6735/* 6736** CAPI3REF: Checkpoint a database 6737** 6738** ^The [sqlite3_wal_checkpoint(D,X)] interface causes database named X 6739** on [database connection] D to be [checkpointed]. ^If X is NULL or an 6740** empty string, then a checkpoint is run on all databases of 6741** connection D. ^If the database connection D is not in 6742** [WAL | write-ahead log mode] then this interface is a harmless no-op. 6743** 6744** ^The [wal_checkpoint pragma] can be used to invoke this interface 6745** from SQL. ^The [sqlite3_wal_autocheckpoint()] interface and the 6746** [wal_autocheckpoint pragma] can be used to cause this interface to be 6747** run whenever the WAL reaches a certain size threshold. 6748** 6749** See also: [sqlite3_wal_checkpoint_v2()] 6750*/ 6751SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb); 6752 6753/* 6754** CAPI3REF: Checkpoint a database 6755** 6756** Run a checkpoint operation on WAL database zDb attached to database 6757** handle db. The specific operation is determined by the value of the 6758** eMode parameter: 6759** 6760** <dl> 6761** <dt>SQLITE_CHECKPOINT_PASSIVE<dd> 6762** Checkpoint as many frames as possible without waiting for any database 6763** readers or writers to finish. Sync the db file if all frames in the log 6764** are checkpointed. This mode is the same as calling 6765** sqlite3_wal_checkpoint(). The busy-handler callback is never invoked. 6766** 6767** <dt>SQLITE_CHECKPOINT_FULL<dd> 6768** This mode blocks (calls the busy-handler callback) until there is no 6769** database writer and all readers are reading from the most recent database 6770** snapshot. It then checkpoints all frames in the log file and syncs the 6771** database file. This call blocks database writers while it is running, 6772** but not database readers. 6773** 6774** <dt>SQLITE_CHECKPOINT_RESTART<dd> 6775** This mode works the same way as SQLITE_CHECKPOINT_FULL, except after 6776** checkpointing the log file it blocks (calls the busy-handler callback) 6777** until all readers are reading from the database file only. This ensures 6778** that the next client to write to the database file restarts the log file 6779** from the beginning. This call blocks database writers while it is running, 6780** but not database readers. 6781** </dl> 6782** 6783** If pnLog is not NULL, then *pnLog is set to the total number of frames in 6784** the log file before returning. If pnCkpt is not NULL, then *pnCkpt is set to 6785** the total number of checkpointed frames (including any that were already 6786** checkpointed when this function is called). *pnLog and *pnCkpt may be 6787** populated even if sqlite3_wal_checkpoint_v2() returns other than SQLITE_OK. 6788** If no values are available because of an error, they are both set to -1 6789** before returning to communicate this to the caller. 6790** 6791** All calls obtain an exclusive "checkpoint" lock on the database file. If 6792** any other process is running a checkpoint operation at the same time, the 6793** lock cannot be obtained and SQLITE_BUSY is returned. Even if there is a 6794** busy-handler configured, it will not be invoked in this case. 6795** 6796** The SQLITE_CHECKPOINT_FULL and RESTART modes also obtain the exclusive 6797** "writer" lock on the database file. If the writer lock cannot be obtained 6798** immediately, and a busy-handler is configured, it is invoked and the writer 6799** lock retried until either the busy-handler returns 0 or the lock is 6800** successfully obtained. The busy-handler is also invoked while waiting for 6801** database readers as described above. If the busy-handler returns 0 before 6802** the writer lock is obtained or while waiting for database readers, the 6803** checkpoint operation proceeds from that point in the same way as 6804** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 6805** without blocking any further. SQLITE_BUSY is returned in this case. 6806** 6807** If parameter zDb is NULL or points to a zero length string, then the 6808** specified operation is attempted on all WAL databases. In this case the 6809** values written to output parameters *pnLog and *pnCkpt are undefined. If 6810** an SQLITE_BUSY error is encountered when processing one or more of the 6811** attached WAL databases, the operation is still attempted on any remaining 6812** attached databases and SQLITE_BUSY is returned to the caller. If any other 6813** error occurs while processing an attached database, processing is abandoned 6814** and the error code returned to the caller immediately. If no error 6815** (SQLITE_BUSY or otherwise) is encountered while processing the attached 6816** databases, SQLITE_OK is returned. 6817** 6818** If database zDb is the name of an attached database that is not in WAL 6819** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. If 6820** zDb is not NULL (or a zero length string) and is not the name of any 6821** attached database, SQLITE_ERROR is returned to the caller. 6822*/ 6823SQLITE_API int sqlite3_wal_checkpoint_v2( 6824 sqlite3 *db, /* Database handle */ 6825 const char *zDb, /* Name of attached database (or NULL) */ 6826 int eMode, /* SQLITE_CHECKPOINT_* value */ 6827 int *pnLog, /* OUT: Size of WAL log in frames */ 6828 int *pnCkpt /* OUT: Total number of frames checkpointed */ 6829); 6830 6831/* 6832** CAPI3REF: Checkpoint operation parameters 6833** 6834** These constants can be used as the 3rd parameter to 6835** [sqlite3_wal_checkpoint_v2()]. See the [sqlite3_wal_checkpoint_v2()] 6836** documentation for additional information about the meaning and use of 6837** each of these values. 6838*/ 6839#define SQLITE_CHECKPOINT_PASSIVE 0 6840#define SQLITE_CHECKPOINT_FULL 1 6841#define SQLITE_CHECKPOINT_RESTART 2 6842 6843/* 6844** CAPI3REF: Virtual Table Interface Configuration 6845** 6846** This function may be called by either the [xConnect] or [xCreate] method 6847** of a [virtual table] implementation to configure 6848** various facets of the virtual table interface. 6849** 6850** If this interface is invoked outside the context of an xConnect or 6851** xCreate virtual table method then the behavior is undefined. 6852** 6853** At present, there is only one option that may be configured using 6854** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].) Further options 6855** may be added in the future. 6856*/ 6857SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...); 6858 6859/* 6860** CAPI3REF: Virtual Table Configuration Options 6861** 6862** These macros define the various options to the 6863** [sqlite3_vtab_config()] interface that [virtual table] implementations 6864** can use to customize and optimize their behavior. 6865** 6866** <dl> 6867** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT 6868** <dd>Calls of the form 6869** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported, 6870** where X is an integer. If X is zero, then the [virtual table] whose 6871** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not 6872** support constraints. In this configuration (which is the default) if 6873** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire 6874** statement is rolled back as if [ON CONFLICT | OR ABORT] had been 6875** specified as part of the users SQL statement, regardless of the actual 6876** ON CONFLICT mode specified. 6877** 6878** If X is non-zero, then the virtual table implementation guarantees 6879** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before 6880** any modifications to internal or persistent data structures have been made. 6881** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 6882** is able to roll back a statement or database transaction, and abandon 6883** or continue processing the current SQL statement as appropriate. 6884** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns 6885** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode 6886** had been ABORT. 6887** 6888** Virtual table implementations that are required to handle OR REPLACE 6889** must do so within the [xUpdate] method. If a call to the 6890** [sqlite3_vtab_on_conflict()] function indicates that the current ON 6891** CONFLICT policy is REPLACE, the virtual table implementation should 6892** silently replace the appropriate rows within the xUpdate callback and 6893** return SQLITE_OK. Or, if this is not possible, it may return 6894** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 6895** constraint handling. 6896** </dl> 6897*/ 6898#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1 6899 6900/* 6901** CAPI3REF: Determine The Virtual Table Conflict Policy 6902** 6903** This function may only be called from within a call to the [xUpdate] method 6904** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The 6905** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL], 6906** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode 6907** of the SQL statement that triggered the call to the [xUpdate] method of the 6908** [virtual table]. 6909*/ 6910SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *); 6911 6912/* 6913** CAPI3REF: Conflict resolution modes 6914** 6915** These constants are returned by [sqlite3_vtab_on_conflict()] to 6916** inform a [virtual table] implementation what the [ON CONFLICT] mode 6917** is for the SQL statement being evaluated. 6918** 6919** Note that the [SQLITE_IGNORE] constant is also used as a potential 6920** return value from the [sqlite3_set_authorizer()] callback and that 6921** [SQLITE_ABORT] is also a [result code]. 6922*/ 6923#define SQLITE_ROLLBACK 1 6924/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */ 6925#define SQLITE_FAIL 3 6926/* #define SQLITE_ABORT 4 // Also an error code */ 6927#define SQLITE_REPLACE 5 6928 6929 6930 6931/* 6932** Undo the hack that converts floating point types to integer for 6933** builds on processors without floating point support. 6934*/ 6935#ifdef SQLITE_OMIT_FLOATING_POINT 6936# undef double 6937#endif 6938 6939#ifdef __cplusplus 6940} /* End of the 'extern "C"' block */ 6941#endif 6942#endif 6943 6944/* 6945** 2010 August 30 6946** 6947** The author disclaims copyright to this source code. In place of 6948** a legal notice, here is a blessing: 6949** 6950** May you do good and not evil. 6951** May you find forgiveness for yourself and forgive others. 6952** May you share freely, never taking more than you give. 6953** 6954************************************************************************* 6955*/ 6956 6957#ifndef _SQLITE3RTREE_H_ 6958#define _SQLITE3RTREE_H_ 6959 6960 6961#ifdef __cplusplus 6962extern "C" { 6963#endif 6964 6965typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry; 6966 6967/* 6968** Register a geometry callback named zGeom that can be used as part of an 6969** R-Tree geometry query as follows: 6970** 6971** SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...) 6972*/ 6973SQLITE_API int sqlite3_rtree_geometry_callback( 6974 sqlite3 *db, 6975 const char *zGeom, 6976 int (*xGeom)(sqlite3_rtree_geometry *, int nCoord, double *aCoord, int *pRes), 6977 void *pContext 6978); 6979 6980 6981/* 6982** A pointer to a structure of the following type is passed as the first 6983** argument to callbacks registered using rtree_geometry_callback(). 6984*/ 6985struct sqlite3_rtree_geometry { 6986 void *pContext; /* Copy of pContext passed to s_r_g_c() */ 6987 int nParam; /* Size of array aParam[] */ 6988 double *aParam; /* Parameters passed to SQL geom function */ 6989 void *pUser; /* Callback implementation user data */ 6990 void (*xDelUser)(void *); /* Called by SQLite to clean up pUser */ 6991}; 6992 6993 6994#ifdef __cplusplus 6995} /* end of the 'extern "C"' block */ 6996#endif 6997 6998#endif /* ifndef _SQLITE3RTREE_H_ */ 6999 7000