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/* 53** These no-op macros are used in front of interfaces to mark those 54** interfaces as either deprecated or experimental. New applications 55** should not use deprecated interfaces - they are support for backwards 56** compatibility only. Application writers should be aware that 57** experimental interfaces are subject to change in point releases. 58** 59** These macros used to resolve to various kinds of compiler magic that 60** would generate warning messages when they were used. But that 61** compiler magic ended up generating such a flurry of bug reports 62** that we have taken it all out and gone back to using simple 63** noop macros. 64*/ 65#define SQLITE_DEPRECATED 66#define SQLITE_EXPERIMENTAL 67 68/* 69** Ensure these symbols were not defined by some previous header file. 70*/ 71#ifdef SQLITE_VERSION 72# undef SQLITE_VERSION 73#endif 74#ifdef SQLITE_VERSION_NUMBER 75# undef SQLITE_VERSION_NUMBER 76#endif 77 78/* 79** CAPI3REF: Compile-Time Library Version Numbers 80** 81** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header 82** evaluates to a string literal that is the SQLite version in the 83** format "X.Y.Z" where X is the major version number (always 3 for 84** SQLite3) and Y is the minor version number and Z is the release number.)^ 85** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer 86** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same 87** numbers used in [SQLITE_VERSION].)^ 88** The SQLITE_VERSION_NUMBER for any given release of SQLite will also 89** be larger than the release from which it is derived. Either Y will 90** be held constant and Z will be incremented or else Y will be incremented 91** and Z will be reset to zero. 92** 93** Since version 3.6.18, SQLite source code has been stored in the 94** <a href="http://www.fossil-scm.org/">Fossil configuration management 95** system</a>. ^The SQLITE_SOURCE_ID macro evalutes to 96** a string which identifies a particular check-in of SQLite 97** within its configuration management system. ^The SQLITE_SOURCE_ID 98** string contains the date and time of the check-in (UTC) and an SHA1 99** hash of the entire source tree. 100** 101** See also: [sqlite3_libversion()], 102** [sqlite3_libversion_number()], [sqlite3_sourceid()], 103** [sqlite_version()] and [sqlite_source_id()]. 104*/ 105#define SQLITE_VERSION "--VERS--" 106#define SQLITE_VERSION_NUMBER --VERSION-NUMBER-- 107#define SQLITE_SOURCE_ID "--SOURCE-ID--" 108 109/* 110** CAPI3REF: Run-Time Library Version Numbers 111** KEYWORDS: sqlite3_version 112** 113** These interfaces provide the same information as the [SQLITE_VERSION], 114** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros 115** but are associated with the library instead of the header file. ^(Cautious 116** programmers might include assert() statements in their application to 117** verify that values returned by these interfaces match the macros in 118** the header, and thus insure that the application is 119** compiled with matching library and header files. 120** 121** <blockquote><pre> 122** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER ); 123** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==0 ); 124** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 ); 125** </pre></blockquote>)^ 126** 127** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION] 128** macro. ^The sqlite3_libversion() function returns a pointer to the 129** to the sqlite3_version[] string constant. The sqlite3_libversion() 130** function is provided for use in DLLs since DLL users usually do not have 131** direct access to string constants within the DLL. ^The 132** sqlite3_libversion_number() function returns an integer equal to 133** [SQLITE_VERSION_NUMBER]. ^The sqlite3_sourceid() function a pointer 134** to a string constant whose value is the same as the [SQLITE_SOURCE_ID] 135** C preprocessor macro. 136** 137** See also: [sqlite_version()] and [sqlite_source_id()]. 138*/ 139SQLITE_EXTERN const char sqlite3_version[]; 140const char *sqlite3_libversion(void); 141const char *sqlite3_sourceid(void); 142int sqlite3_libversion_number(void); 143 144/* 145** CAPI3REF: Test To See If The Library Is Threadsafe 146** 147** ^The sqlite3_threadsafe() function returns zero if and only if 148** SQLite was compiled mutexing code omitted due to the 149** [SQLITE_THREADSAFE] compile-time option being set to 0. 150** 151** SQLite can be compiled with or without mutexes. When 152** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes 153** are enabled and SQLite is threadsafe. When the 154** [SQLITE_THREADSAFE] macro is 0, 155** the mutexes are omitted. Without the mutexes, it is not safe 156** to use SQLite concurrently from more than one thread. 157** 158** Enabling mutexes incurs a measurable performance penalty. 159** So if speed is of utmost importance, it makes sense to disable 160** the mutexes. But for maximum safety, mutexes should be enabled. 161** ^The default behavior is for mutexes to be enabled. 162** 163** This interface can be used by an application to make sure that the 164** version of SQLite that it is linking against was compiled with 165** the desired setting of the [SQLITE_THREADSAFE] macro. 166** 167** This interface only reports on the compile-time mutex setting 168** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with 169** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but 170** can be fully or partially disabled using a call to [sqlite3_config()] 171** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], 172** or [SQLITE_CONFIG_MUTEX]. ^(The return value of the 173** sqlite3_threadsafe() function shows only the compile-time setting of 174** thread safety, not any run-time changes to that setting made by 175** sqlite3_config(). In other words, the return value from sqlite3_threadsafe() 176** is unchanged by calls to sqlite3_config().)^ 177** 178** See the [threading mode] documentation for additional information. 179*/ 180int sqlite3_threadsafe(void); 181 182/* 183** CAPI3REF: Database Connection Handle 184** KEYWORDS: {database connection} {database connections} 185** 186** Each open SQLite database is represented by a pointer to an instance of 187** the opaque structure named "sqlite3". It is useful to think of an sqlite3 188** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and 189** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] 190** is its destructor. There are many other interfaces (such as 191** [sqlite3_prepare_v2()], [sqlite3_create_function()], and 192** [sqlite3_busy_timeout()] to name but three) that are methods on an 193** sqlite3 object. 194*/ 195typedef struct sqlite3 sqlite3; 196 197/* 198** CAPI3REF: 64-Bit Integer Types 199** KEYWORDS: sqlite_int64 sqlite_uint64 200** 201** Because there is no cross-platform way to specify 64-bit integer types 202** SQLite includes typedefs for 64-bit signed and unsigned integers. 203** 204** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. 205** The sqlite_int64 and sqlite_uint64 types are supported for backwards 206** compatibility only. 207** 208** ^The sqlite3_int64 and sqlite_int64 types can store integer values 209** between -9223372036854775808 and +9223372036854775807 inclusive. ^The 210** sqlite3_uint64 and sqlite_uint64 types can store integer values 211** between 0 and +18446744073709551615 inclusive. 212*/ 213#ifdef SQLITE_INT64_TYPE 214 typedef SQLITE_INT64_TYPE sqlite_int64; 215 typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; 216#elif defined(_MSC_VER) || defined(__BORLANDC__) 217 typedef __int64 sqlite_int64; 218 typedef unsigned __int64 sqlite_uint64; 219#else 220 typedef long long int sqlite_int64; 221 typedef unsigned long long int sqlite_uint64; 222#endif 223typedef sqlite_int64 sqlite3_int64; 224typedef sqlite_uint64 sqlite3_uint64; 225 226/* 227** If compiling for a processor that lacks floating point support, 228** substitute integer for floating-point. 229*/ 230#ifdef SQLITE_OMIT_FLOATING_POINT 231# define double sqlite3_int64 232#endif 233 234/* 235** CAPI3REF: Closing A Database Connection 236** 237** ^The sqlite3_close() routine is the destructor for the [sqlite3] object. 238** ^Calls to sqlite3_close() return SQLITE_OK if the [sqlite3] object is 239** successfullly destroyed and all associated resources are deallocated. 240** 241** Applications must [sqlite3_finalize | finalize] all [prepared statements] 242** and [sqlite3_blob_close | close] all [BLOB handles] associated with 243** the [sqlite3] object prior to attempting to close the object. ^If 244** sqlite3_close() is called on a [database connection] that still has 245** outstanding [prepared statements] or [BLOB handles], then it returns 246** SQLITE_BUSY. 247** 248** ^If [sqlite3_close()] is invoked while a transaction is open, 249** the transaction is automatically rolled back. 250** 251** The C parameter to [sqlite3_close(C)] must be either a NULL 252** pointer or an [sqlite3] object pointer obtained 253** from [sqlite3_open()], [sqlite3_open16()], or 254** [sqlite3_open_v2()], and not previously closed. 255** ^Calling sqlite3_close() with a NULL pointer argument is a 256** harmless no-op. 257*/ 258int sqlite3_close(sqlite3 *); 259 260/* 261** The type for a callback function. 262** This is legacy and deprecated. It is included for historical 263** compatibility and is not documented. 264*/ 265typedef int (*sqlite3_callback)(void*,int,char**, char**); 266 267/* 268** CAPI3REF: One-Step Query Execution Interface 269** 270** The sqlite3_exec() interface is a convenience wrapper around 271** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()], 272** that allows an application to run multiple statements of SQL 273** without having to use a lot of C code. 274** 275** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded, 276** semicolon-separate SQL statements passed into its 2nd argument, 277** in the context of the [database connection] passed in as its 1st 278** argument. ^If the callback function of the 3rd argument to 279** sqlite3_exec() is not NULL, then it is invoked for each result row 280** coming out of the evaluated SQL statements. ^The 4th argument to 281** to sqlite3_exec() is relayed through to the 1st argument of each 282** callback invocation. ^If the callback pointer to sqlite3_exec() 283** is NULL, then no callback is ever invoked and result rows are 284** ignored. 285** 286** ^If an error occurs while evaluating the SQL statements passed into 287** sqlite3_exec(), then execution of the current statement stops and 288** subsequent statements are skipped. ^If the 5th parameter to sqlite3_exec() 289** is not NULL then any error message is written into memory obtained 290** from [sqlite3_malloc()] and passed back through the 5th parameter. 291** To avoid memory leaks, the application should invoke [sqlite3_free()] 292** on error message strings returned through the 5th parameter of 293** of sqlite3_exec() after the error message string is no longer needed. 294** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors 295** occur, then sqlite3_exec() sets the pointer in its 5th parameter to 296** NULL before returning. 297** 298** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec() 299** routine returns SQLITE_ABORT without invoking the callback again and 300** without running any subsequent SQL statements. 301** 302** ^The 2nd argument to the sqlite3_exec() callback function is the 303** number of columns in the result. ^The 3rd argument to the sqlite3_exec() 304** callback is an array of pointers to strings obtained as if from 305** [sqlite3_column_text()], one for each column. ^If an element of a 306** result row is NULL then the corresponding string pointer for the 307** sqlite3_exec() callback is a NULL pointer. ^The 4th argument to the 308** sqlite3_exec() callback is an array of pointers to strings where each 309** entry represents the name of corresponding result column as obtained 310** from [sqlite3_column_name()]. 311** 312** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer 313** to an empty string, or a pointer that contains only whitespace and/or 314** SQL comments, then no SQL statements are evaluated and the database 315** is not changed. 316** 317** Restrictions: 318** 319** <ul> 320** <li> The application must insure that the 1st parameter to sqlite3_exec() 321** is a valid and open [database connection]. 322** <li> The application must not close [database connection] specified by 323** the 1st parameter to sqlite3_exec() while sqlite3_exec() is running. 324** <li> The application must not modify the SQL statement text passed into 325** the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running. 326** </ul> 327*/ 328int sqlite3_exec( 329 sqlite3*, /* An open database */ 330 const char *sql, /* SQL to be evaluated */ 331 int (*callback)(void*,int,char**,char**), /* Callback function */ 332 void *, /* 1st argument to callback */ 333 char **errmsg /* Error msg written here */ 334); 335 336/* 337** CAPI3REF: Result Codes 338** KEYWORDS: SQLITE_OK {error code} {error codes} 339** KEYWORDS: {result code} {result codes} 340** 341** Many SQLite functions return an integer result code from the set shown 342** here in order to indicates success or failure. 343** 344** New error codes may be added in future versions of SQLite. 345** 346** See also: [SQLITE_IOERR_READ | extended result codes] 347*/ 348#define SQLITE_OK 0 /* Successful result */ 349/* beginning-of-error-codes */ 350#define SQLITE_ERROR 1 /* SQL error or missing database */ 351#define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ 352#define SQLITE_PERM 3 /* Access permission denied */ 353#define SQLITE_ABORT 4 /* Callback routine requested an abort */ 354#define SQLITE_BUSY 5 /* The database file is locked */ 355#define SQLITE_LOCKED 6 /* A table in the database is locked */ 356#define SQLITE_NOMEM 7 /* A malloc() failed */ 357#define SQLITE_READONLY 8 /* Attempt to write a readonly database */ 358#define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ 359#define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ 360#define SQLITE_CORRUPT 11 /* The database disk image is malformed */ 361#define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ 362#define SQLITE_FULL 13 /* Insertion failed because database is full */ 363#define SQLITE_CANTOPEN 14 /* Unable to open the database file */ 364#define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ 365#define SQLITE_EMPTY 16 /* Database is empty */ 366#define SQLITE_SCHEMA 17 /* The database schema changed */ 367#define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ 368#define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ 369#define SQLITE_MISMATCH 20 /* Data type mismatch */ 370#define SQLITE_MISUSE 21 /* Library used incorrectly */ 371#define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ 372#define SQLITE_AUTH 23 /* Authorization denied */ 373#define SQLITE_FORMAT 24 /* Auxiliary database format error */ 374#define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ 375#define SQLITE_NOTADB 26 /* File opened that is not a database file */ 376#define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ 377#define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ 378/* end-of-error-codes */ 379 380/* 381** CAPI3REF: Extended Result Codes 382** KEYWORDS: {extended error code} {extended error codes} 383** KEYWORDS: {extended result code} {extended result codes} 384** 385** In its default configuration, SQLite API routines return one of 26 integer 386** [SQLITE_OK | result codes]. However, experience has shown that many of 387** these result codes are too coarse-grained. They do not provide as 388** much information about problems as programmers might like. In an effort to 389** address this, newer versions of SQLite (version 3.3.8 and later) include 390** support for additional result codes that provide more detailed information 391** about errors. The extended result codes are enabled or disabled 392** on a per database connection basis using the 393** [sqlite3_extended_result_codes()] API. 394** 395** Some of the available extended result codes are listed here. 396** One may expect the number of extended result codes will be expand 397** over time. Software that uses extended result codes should expect 398** to see new result codes in future releases of SQLite. 399** 400** The SQLITE_OK result code will never be extended. It will always 401** be exactly zero. 402*/ 403#define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) 404#define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) 405#define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) 406#define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) 407#define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) 408#define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) 409#define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) 410#define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) 411#define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) 412#define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) 413#define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) 414#define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) 415#define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) 416#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) 417#define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) 418#define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) 419#define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) 420#define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) 421 422/* 423** CAPI3REF: Flags For File Open Operations 424** 425** These bit values are intended for use in the 426** 3rd parameter to the [sqlite3_open_v2()] interface and 427** in the 4th parameter to the xOpen method of the 428** [sqlite3_vfs] object. 429*/ 430#define SQLITE_OPEN_READONLY 0x00000001 /* Ok for sqlite3_open_v2() */ 431#define SQLITE_OPEN_READWRITE 0x00000002 /* Ok for sqlite3_open_v2() */ 432#define SQLITE_OPEN_CREATE 0x00000004 /* Ok for sqlite3_open_v2() */ 433#define SQLITE_OPEN_DELETEONCLOSE 0x00000008 /* VFS only */ 434#define SQLITE_OPEN_EXCLUSIVE 0x00000010 /* VFS only */ 435#define SQLITE_OPEN_MAIN_DB 0x00000100 /* VFS only */ 436#define SQLITE_OPEN_TEMP_DB 0x00000200 /* VFS only */ 437#define SQLITE_OPEN_TRANSIENT_DB 0x00000400 /* VFS only */ 438#define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 /* VFS only */ 439#define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 /* VFS only */ 440#define SQLITE_OPEN_SUBJOURNAL 0x00002000 /* VFS only */ 441#define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 /* VFS only */ 442#define SQLITE_OPEN_NOMUTEX 0x00008000 /* Ok for sqlite3_open_v2() */ 443#define SQLITE_OPEN_FULLMUTEX 0x00010000 /* Ok for sqlite3_open_v2() */ 444#define SQLITE_OPEN_SHAREDCACHE 0x00020000 /* Ok for sqlite3_open_v2() */ 445#define SQLITE_OPEN_PRIVATECACHE 0x00040000 /* Ok for sqlite3_open_v2() */ 446 447/* 448** CAPI3REF: Device Characteristics 449** 450** The xDeviceCapabilities method of the [sqlite3_io_methods] 451** object returns an integer which is a vector of the these 452** bit values expressing I/O characteristics of the mass storage 453** device that holds the file that the [sqlite3_io_methods] 454** refers to. 455** 456** The SQLITE_IOCAP_ATOMIC property means that all writes of 457** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 458** mean that writes of blocks that are nnn bytes in size and 459** are aligned to an address which is an integer multiple of 460** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 461** that when data is appended to a file, the data is appended 462** first then the size of the file is extended, never the other 463** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 464** information is written to disk in the same order as calls 465** to xWrite(). 466*/ 467#define SQLITE_IOCAP_ATOMIC 0x00000001 468#define SQLITE_IOCAP_ATOMIC512 0x00000002 469#define SQLITE_IOCAP_ATOMIC1K 0x00000004 470#define SQLITE_IOCAP_ATOMIC2K 0x00000008 471#define SQLITE_IOCAP_ATOMIC4K 0x00000010 472#define SQLITE_IOCAP_ATOMIC8K 0x00000020 473#define SQLITE_IOCAP_ATOMIC16K 0x00000040 474#define SQLITE_IOCAP_ATOMIC32K 0x00000080 475#define SQLITE_IOCAP_ATOMIC64K 0x00000100 476#define SQLITE_IOCAP_SAFE_APPEND 0x00000200 477#define SQLITE_IOCAP_SEQUENTIAL 0x00000400 478 479/* 480** CAPI3REF: File Locking Levels 481** 482** SQLite uses one of these integer values as the second 483** argument to calls it makes to the xLock() and xUnlock() methods 484** of an [sqlite3_io_methods] object. 485*/ 486#define SQLITE_LOCK_NONE 0 487#define SQLITE_LOCK_SHARED 1 488#define SQLITE_LOCK_RESERVED 2 489#define SQLITE_LOCK_PENDING 3 490#define SQLITE_LOCK_EXCLUSIVE 4 491 492/* 493** CAPI3REF: Synchronization Type Flags 494** 495** When SQLite invokes the xSync() method of an 496** [sqlite3_io_methods] object it uses a combination of 497** these integer values as the second argument. 498** 499** When the SQLITE_SYNC_DATAONLY flag is used, it means that the 500** sync operation only needs to flush data to mass storage. Inode 501** information need not be flushed. If the lower four bits of the flag 502** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. 503** If the lower four bits equal SQLITE_SYNC_FULL, that means 504** to use Mac OS X style fullsync instead of fsync(). 505*/ 506#define SQLITE_SYNC_NORMAL 0x00002 507#define SQLITE_SYNC_FULL 0x00003 508#define SQLITE_SYNC_DATAONLY 0x00010 509 510/* 511** CAPI3REF: OS Interface Open File Handle 512** 513** An [sqlite3_file] object represents an open file in the 514** [sqlite3_vfs | OS interface layer]. Individual OS interface 515** implementations will 516** want to subclass this object by appending additional fields 517** for their own use. The pMethods entry is a pointer to an 518** [sqlite3_io_methods] object that defines methods for performing 519** I/O operations on the open file. 520*/ 521typedef struct sqlite3_file sqlite3_file; 522struct sqlite3_file { 523 const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ 524}; 525 526/* 527** CAPI3REF: OS Interface File Virtual Methods Object 528** 529** Every file opened by the [sqlite3_vfs] xOpen method populates an 530** [sqlite3_file] object (or, more commonly, a subclass of the 531** [sqlite3_file] object) with a pointer to an instance of this object. 532** This object defines the methods used to perform various operations 533** against the open file represented by the [sqlite3_file] object. 534** 535** If the xOpen method sets the sqlite3_file.pMethods element 536** to a non-NULL pointer, then the sqlite3_io_methods.xClose method 537** may be invoked even if the xOpen reported that it failed. The 538** only way to prevent a call to xClose following a failed xOpen 539** is for the xOpen to set the sqlite3_file.pMethods element to NULL. 540** 541** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or 542** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). 543** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] 544** flag may be ORed in to indicate that only the data of the file 545** and not its inode needs to be synced. 546** 547** The integer values to xLock() and xUnlock() are one of 548** <ul> 549** <li> [SQLITE_LOCK_NONE], 550** <li> [SQLITE_LOCK_SHARED], 551** <li> [SQLITE_LOCK_RESERVED], 552** <li> [SQLITE_LOCK_PENDING], or 553** <li> [SQLITE_LOCK_EXCLUSIVE]. 554** </ul> 555** xLock() increases the lock. xUnlock() decreases the lock. 556** The xCheckReservedLock() method checks whether any database connection, 557** either in this process or in some other process, is holding a RESERVED, 558** PENDING, or EXCLUSIVE lock on the file. It returns true 559** if such a lock exists and false otherwise. 560** 561** The xFileControl() method is a generic interface that allows custom 562** VFS implementations to directly control an open file using the 563** [sqlite3_file_control()] interface. The second "op" argument is an 564** integer opcode. The third argument is a generic pointer intended to 565** point to a structure that may contain arguments or space in which to 566** write return values. Potential uses for xFileControl() might be 567** functions to enable blocking locks with timeouts, to change the 568** locking strategy (for example to use dot-file locks), to inquire 569** about the status of a lock, or to break stale locks. The SQLite 570** core reserves all opcodes less than 100 for its own use. 571** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. 572** Applications that define a custom xFileControl method should use opcodes 573** greater than 100 to avoid conflicts. 574** 575** The xSectorSize() method returns the sector size of the 576** device that underlies the file. The sector size is the 577** minimum write that can be performed without disturbing 578** other bytes in the file. The xDeviceCharacteristics() 579** method returns a bit vector describing behaviors of the 580** underlying device: 581** 582** <ul> 583** <li> [SQLITE_IOCAP_ATOMIC] 584** <li> [SQLITE_IOCAP_ATOMIC512] 585** <li> [SQLITE_IOCAP_ATOMIC1K] 586** <li> [SQLITE_IOCAP_ATOMIC2K] 587** <li> [SQLITE_IOCAP_ATOMIC4K] 588** <li> [SQLITE_IOCAP_ATOMIC8K] 589** <li> [SQLITE_IOCAP_ATOMIC16K] 590** <li> [SQLITE_IOCAP_ATOMIC32K] 591** <li> [SQLITE_IOCAP_ATOMIC64K] 592** <li> [SQLITE_IOCAP_SAFE_APPEND] 593** <li> [SQLITE_IOCAP_SEQUENTIAL] 594** </ul> 595** 596** The SQLITE_IOCAP_ATOMIC property means that all writes of 597** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values 598** mean that writes of blocks that are nnn bytes in size and 599** are aligned to an address which is an integer multiple of 600** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means 601** that when data is appended to a file, the data is appended 602** first then the size of the file is extended, never the other 603** way around. The SQLITE_IOCAP_SEQUENTIAL property means that 604** information is written to disk in the same order as calls 605** to xWrite(). 606** 607** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill 608** in the unread portions of the buffer with zeros. A VFS that 609** fails to zero-fill short reads might seem to work. However, 610** failure to zero-fill short reads will eventually lead to 611** database corruption. 612*/ 613typedef struct sqlite3_io_methods sqlite3_io_methods; 614struct sqlite3_io_methods { 615 int iVersion; 616 int (*xClose)(sqlite3_file*); 617 int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); 618 int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); 619 int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); 620 int (*xSync)(sqlite3_file*, int flags); 621 int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); 622 int (*xLock)(sqlite3_file*, int); 623 int (*xUnlock)(sqlite3_file*, int); 624 int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); 625 int (*xFileControl)(sqlite3_file*, int op, void *pArg); 626 int (*xSectorSize)(sqlite3_file*); 627 int (*xDeviceCharacteristics)(sqlite3_file*); 628 /* Additional methods may be added in future releases */ 629}; 630 631/* 632** CAPI3REF: Standard File Control Opcodes 633** 634** These integer constants are opcodes for the xFileControl method 635** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] 636** interface. 637** 638** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This 639** opcode causes the xFileControl method to write the current state of 640** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], 641** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) 642** into an integer that the pArg argument points to. This capability 643** is used during testing and only needs to be supported when SQLITE_TEST 644** is defined. 645*/ 646#define SQLITE_FCNTL_LOCKSTATE 1 647#define SQLITE_GET_LOCKPROXYFILE 2 648#define SQLITE_SET_LOCKPROXYFILE 3 649#define SQLITE_LAST_ERRNO 4 650 651/* 652** CAPI3REF: Mutex Handle 653** 654** The mutex module within SQLite defines [sqlite3_mutex] to be an 655** abstract type for a mutex object. The SQLite core never looks 656** at the internal representation of an [sqlite3_mutex]. It only 657** deals with pointers to the [sqlite3_mutex] object. 658** 659** Mutexes are created using [sqlite3_mutex_alloc()]. 660*/ 661typedef struct sqlite3_mutex sqlite3_mutex; 662 663/* 664** CAPI3REF: OS Interface Object 665** 666** An instance of the sqlite3_vfs object defines the interface between 667** the SQLite core and the underlying operating system. The "vfs" 668** in the name of the object stands for "virtual file system". 669** 670** The value of the iVersion field is initially 1 but may be larger in 671** future versions of SQLite. Additional fields may be appended to this 672** object when the iVersion value is increased. Note that the structure 673** of the sqlite3_vfs object changes in the transaction between 674** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not 675** modified. 676** 677** The szOsFile field is the size of the subclassed [sqlite3_file] 678** structure used by this VFS. mxPathname is the maximum length of 679** a pathname in this VFS. 680** 681** Registered sqlite3_vfs objects are kept on a linked list formed by 682** the pNext pointer. The [sqlite3_vfs_register()] 683** and [sqlite3_vfs_unregister()] interfaces manage this list 684** in a thread-safe way. The [sqlite3_vfs_find()] interface 685** searches the list. Neither the application code nor the VFS 686** implementation should use the pNext pointer. 687** 688** The pNext field is the only field in the sqlite3_vfs 689** structure that SQLite will ever modify. SQLite will only access 690** or modify this field while holding a particular static mutex. 691** The application should never modify anything within the sqlite3_vfs 692** object once the object has been registered. 693** 694** The zName field holds the name of the VFS module. The name must 695** be unique across all VFS modules. 696** 697** SQLite will guarantee that the zFilename parameter to xOpen 698** is either a NULL pointer or string obtained 699** from xFullPathname(). SQLite further guarantees that 700** the string will be valid and unchanged until xClose() is 701** called. Because of the previous sentence, 702** the [sqlite3_file] can safely store a pointer to the 703** filename if it needs to remember the filename for some reason. 704** If the zFilename parameter is xOpen is a NULL pointer then xOpen 705** must invent its own temporary name for the file. Whenever the 706** xFilename parameter is NULL it will also be the case that the 707** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. 708** 709** The flags argument to xOpen() includes all bits set in 710** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] 711** or [sqlite3_open16()] is used, then flags includes at least 712** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 713** If xOpen() opens a file read-only then it sets *pOutFlags to 714** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. 715** 716** SQLite will also add one of the following flags to the xOpen() 717** call, depending on the object being opened: 718** 719** <ul> 720** <li> [SQLITE_OPEN_MAIN_DB] 721** <li> [SQLITE_OPEN_MAIN_JOURNAL] 722** <li> [SQLITE_OPEN_TEMP_DB] 723** <li> [SQLITE_OPEN_TEMP_JOURNAL] 724** <li> [SQLITE_OPEN_TRANSIENT_DB] 725** <li> [SQLITE_OPEN_SUBJOURNAL] 726** <li> [SQLITE_OPEN_MASTER_JOURNAL] 727** </ul> 728** 729** The file I/O implementation can use the object type flags to 730** change the way it deals with files. For example, an application 731** that does not care about crash recovery or rollback might make 732** the open of a journal file a no-op. Writes to this journal would 733** also be no-ops, and any attempt to read the journal would return 734** SQLITE_IOERR. Or the implementation might recognize that a database 735** file will be doing page-aligned sector reads and writes in a random 736** order and set up its I/O subsystem accordingly. 737** 738** SQLite might also add one of the following flags to the xOpen method: 739** 740** <ul> 741** <li> [SQLITE_OPEN_DELETEONCLOSE] 742** <li> [SQLITE_OPEN_EXCLUSIVE] 743** </ul> 744** 745** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be 746** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] 747** will be set for TEMP databases, journals and for subjournals. 748** 749** The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction 750** with the [SQLITE_OPEN_CREATE] flag, which are both directly 751** analogous to the O_EXCL and O_CREAT flags of the POSIX open() 752** API. The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 753** SQLITE_OPEN_CREATE, is used to indicate that file should always 754** be created, and that it is an error if it already exists. 755** It is <i>not</i> used to indicate the file should be opened 756** for exclusive access. 757** 758** At least szOsFile bytes of memory are allocated by SQLite 759** to hold the [sqlite3_file] structure passed as the third 760** argument to xOpen. The xOpen method does not have to 761** allocate the structure; it should just fill it in. Note that 762** the xOpen method must set the sqlite3_file.pMethods to either 763** a valid [sqlite3_io_methods] object or to NULL. xOpen must do 764** this even if the open fails. SQLite expects that the sqlite3_file.pMethods 765** element will be valid after xOpen returns regardless of the success 766** or failure of the xOpen call. 767** 768** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 769** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to 770** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] 771** to test whether a file is at least readable. The file can be a 772** directory. 773** 774** SQLite will always allocate at least mxPathname+1 bytes for the 775** output buffer xFullPathname. The exact size of the output buffer 776** is also passed as a parameter to both methods. If the output buffer 777** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is 778** handled as a fatal error by SQLite, vfs implementations should endeavor 779** to prevent this by setting mxPathname to a sufficiently large value. 780** 781** The xRandomness(), xSleep(), and xCurrentTime() interfaces 782** are not strictly a part of the filesystem, but they are 783** included in the VFS structure for completeness. 784** The xRandomness() function attempts to return nBytes bytes 785** of good-quality randomness into zOut. The return value is 786** the actual number of bytes of randomness obtained. 787** The xSleep() method causes the calling thread to sleep for at 788** least the number of microseconds given. The xCurrentTime() 789** method returns a Julian Day Number for the current date and time. 790** 791*/ 792typedef struct sqlite3_vfs sqlite3_vfs; 793struct sqlite3_vfs { 794 int iVersion; /* Structure version number */ 795 int szOsFile; /* Size of subclassed sqlite3_file */ 796 int mxPathname; /* Maximum file pathname length */ 797 sqlite3_vfs *pNext; /* Next registered VFS */ 798 const char *zName; /* Name of this virtual file system */ 799 void *pAppData; /* Pointer to application-specific data */ 800 int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, 801 int flags, int *pOutFlags); 802 int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); 803 int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); 804 int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); 805 void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); 806 void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); 807 void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); 808 void (*xDlClose)(sqlite3_vfs*, void*); 809 int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); 810 int (*xSleep)(sqlite3_vfs*, int microseconds); 811 int (*xCurrentTime)(sqlite3_vfs*, double*); 812 int (*xGetLastError)(sqlite3_vfs*, int, char *); 813 /* New fields may be appended in figure versions. The iVersion 814 ** value will increment whenever this happens. */ 815}; 816 817/* 818** CAPI3REF: Flags for the xAccess VFS method 819** 820** These integer constants can be used as the third parameter to 821** the xAccess method of an [sqlite3_vfs] object. They determine 822** what kind of permissions the xAccess method is looking for. 823** With SQLITE_ACCESS_EXISTS, the xAccess method 824** simply checks whether the file exists. 825** With SQLITE_ACCESS_READWRITE, the xAccess method 826** checks whether the file is both readable and writable. 827** With SQLITE_ACCESS_READ, the xAccess method 828** checks whether the file is readable. 829*/ 830#define SQLITE_ACCESS_EXISTS 0 831#define SQLITE_ACCESS_READWRITE 1 832#define SQLITE_ACCESS_READ 2 833 834/* 835** CAPI3REF: Initialize The SQLite Library 836** 837** ^The sqlite3_initialize() routine initializes the 838** SQLite library. ^The sqlite3_shutdown() routine 839** deallocates any resources that were allocated by sqlite3_initialize(). 840** These routines are designed to aid in process initialization and 841** shutdown on embedded systems. Workstation applications using 842** SQLite normally do not need to invoke either of these routines. 843** 844** A call to sqlite3_initialize() is an "effective" call if it is 845** the first time sqlite3_initialize() is invoked during the lifetime of 846** the process, or if it is the first time sqlite3_initialize() is invoked 847** following a call to sqlite3_shutdown(). ^(Only an effective call 848** of sqlite3_initialize() does any initialization. All other calls 849** are harmless no-ops.)^ 850** 851** A call to sqlite3_shutdown() is an "effective" call if it is the first 852** call to sqlite3_shutdown() since the last sqlite3_initialize(). ^(Only 853** an effective call to sqlite3_shutdown() does any deinitialization. 854** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^ 855** 856** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown() 857** is not. The sqlite3_shutdown() interface must only be called from a 858** single thread. All open [database connections] must be closed and all 859** other SQLite resources must be deallocated prior to invoking 860** sqlite3_shutdown(). 861** 862** Among other things, ^sqlite3_initialize() will invoke 863** sqlite3_os_init(). Similarly, ^sqlite3_shutdown() 864** will invoke sqlite3_os_end(). 865** 866** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success. 867** ^If for some reason, sqlite3_initialize() is unable to initialize 868** the library (perhaps it is unable to allocate a needed resource such 869** as a mutex) it returns an [error code] other than [SQLITE_OK]. 870** 871** ^The sqlite3_initialize() routine is called internally by many other 872** SQLite interfaces so that an application usually does not need to 873** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] 874** calls sqlite3_initialize() so the SQLite library will be automatically 875** initialized when [sqlite3_open()] is called if it has not be initialized 876** already. ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] 877** compile-time option, then the automatic calls to sqlite3_initialize() 878** are omitted and the application must call sqlite3_initialize() directly 879** prior to using any other SQLite interface. For maximum portability, 880** it is recommended that applications always invoke sqlite3_initialize() 881** directly prior to using any other SQLite interface. Future releases 882** of SQLite may require this. In other words, the behavior exhibited 883** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the 884** default behavior in some future release of SQLite. 885** 886** The sqlite3_os_init() routine does operating-system specific 887** initialization of the SQLite library. The sqlite3_os_end() 888** routine undoes the effect of sqlite3_os_init(). Typical tasks 889** performed by these routines include allocation or deallocation 890** of static resources, initialization of global variables, 891** setting up a default [sqlite3_vfs] module, or setting up 892** a default configuration using [sqlite3_config()]. 893** 894** The application should never invoke either sqlite3_os_init() 895** or sqlite3_os_end() directly. The application should only invoke 896** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() 897** interface is called automatically by sqlite3_initialize() and 898** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate 899** implementations for sqlite3_os_init() and sqlite3_os_end() 900** are built into SQLite when it is compiled for Unix, Windows, or OS/2. 901** When [custom builds | built for other platforms] 902** (using the [SQLITE_OS_OTHER=1] compile-time 903** option) the application must supply a suitable implementation for 904** sqlite3_os_init() and sqlite3_os_end(). An application-supplied 905** implementation of sqlite3_os_init() or sqlite3_os_end() 906** must return [SQLITE_OK] on success and some other [error code] upon 907** failure. 908*/ 909int sqlite3_initialize(void); 910int sqlite3_shutdown(void); 911int sqlite3_os_init(void); 912int sqlite3_os_end(void); 913 914/* 915** CAPI3REF: Configuring The SQLite Library 916** EXPERIMENTAL 917** 918** The sqlite3_config() interface is used to make global configuration 919** changes to SQLite in order to tune SQLite to the specific needs of 920** the application. The default configuration is recommended for most 921** applications and so this routine is usually not necessary. It is 922** provided to support rare applications with unusual needs. 923** 924** The sqlite3_config() interface is not threadsafe. The application 925** must insure that no other SQLite interfaces are invoked by other 926** threads while sqlite3_config() is running. Furthermore, sqlite3_config() 927** may only be invoked prior to library initialization using 928** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. 929** ^If sqlite3_config() is called after [sqlite3_initialize()] and before 930** [sqlite3_shutdown()] then it will return SQLITE_MISUSE. 931** Note, however, that ^sqlite3_config() can be called as part of the 932** implementation of an application-defined [sqlite3_os_init()]. 933** 934** The first argument to sqlite3_config() is an integer 935** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines 936** what property of SQLite is to be configured. Subsequent arguments 937** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] 938** in the first argument. 939** 940** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. 941** ^If the option is unknown or SQLite is unable to set the option 942** then this routine returns a non-zero [error code]. 943*/ 944SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); 945 946/* 947** CAPI3REF: Configure database connections 948** EXPERIMENTAL 949** 950** The sqlite3_db_config() interface is used to make configuration 951** changes to a [database connection]. The interface is similar to 952** [sqlite3_config()] except that the changes apply to a single 953** [database connection] (specified in the first argument). The 954** sqlite3_db_config() interface should only be used immediately after 955** the database connection is created using [sqlite3_open()], 956** [sqlite3_open16()], or [sqlite3_open_v2()]. 957** 958** The second argument to sqlite3_db_config(D,V,...) is the 959** configuration verb - an integer code that indicates what 960** aspect of the [database connection] is being configured. 961** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. 962** New verbs are likely to be added in future releases of SQLite. 963** Additional arguments depend on the verb. 964** 965** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if 966** the call is considered successful. 967*/ 968SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); 969 970/* 971** CAPI3REF: Memory Allocation Routines 972** EXPERIMENTAL 973** 974** An instance of this object defines the interface between SQLite 975** and low-level memory allocation routines. 976** 977** This object is used in only one place in the SQLite interface. 978** A pointer to an instance of this object is the argument to 979** [sqlite3_config()] when the configuration option is 980** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC]. 981** By creating an instance of this object 982** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC]) 983** during configuration, an application can specify an alternative 984** memory allocation subsystem for SQLite to use for all of its 985** dynamic memory needs. 986** 987** Note that SQLite comes with several [built-in memory allocators] 988** that are perfectly adequate for the overwhelming majority of applications 989** and that this object is only useful to a tiny minority of applications 990** with specialized memory allocation requirements. This object is 991** also used during testing of SQLite in order to specify an alternative 992** memory allocator that simulates memory out-of-memory conditions in 993** order to verify that SQLite recovers gracefully from such 994** conditions. 995** 996** The xMalloc and xFree methods must work like the 997** malloc() and free() functions from the standard C library. 998** The xRealloc method must work like realloc() from the standard C library 999** with the exception that if the second argument to xRealloc is zero, 1000** xRealloc must be a no-op - it must not perform any allocation or 1001** deallocation. ^SQLite guarantees that the second argument to 1002** xRealloc is always a value returned by a prior call to xRoundup. 1003** And so in cases where xRoundup always returns a positive number, 1004** xRealloc can perform exactly as the standard library realloc() and 1005** still be in compliance with this specification. 1006** 1007** xSize should return the allocated size of a memory allocation 1008** previously obtained from xMalloc or xRealloc. The allocated size 1009** is always at least as big as the requested size but may be larger. 1010** 1011** The xRoundup method returns what would be the allocated size of 1012** a memory allocation given a particular requested size. Most memory 1013** allocators round up memory allocations at least to the next multiple 1014** of 8. Some allocators round up to a larger multiple or to a power of 2. 1015** Every memory allocation request coming in through [sqlite3_malloc()] 1016** or [sqlite3_realloc()] first calls xRoundup. If xRoundup returns 0, 1017** that causes the corresponding memory allocation to fail. 1018** 1019** The xInit method initializes the memory allocator. (For example, 1020** it might allocate any require mutexes or initialize internal data 1021** structures. The xShutdown method is invoked (indirectly) by 1022** [sqlite3_shutdown()] and should deallocate any resources acquired 1023** by xInit. The pAppData pointer is used as the only parameter to 1024** xInit and xShutdown. 1025** 1026** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes 1027** the xInit method, so the xInit method need not be threadsafe. The 1028** xShutdown method is only called from [sqlite3_shutdown()] so it does 1029** not need to be threadsafe either. For all other methods, SQLite 1030** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the 1031** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which 1032** it is by default) and so the methods are automatically serialized. 1033** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other 1034** methods must be threadsafe or else make their own arrangements for 1035** serialization. 1036** 1037** SQLite will never invoke xInit() more than once without an intervening 1038** call to xShutdown(). 1039*/ 1040typedef struct sqlite3_mem_methods sqlite3_mem_methods; 1041struct sqlite3_mem_methods { 1042 void *(*xMalloc)(int); /* Memory allocation function */ 1043 void (*xFree)(void*); /* Free a prior allocation */ 1044 void *(*xRealloc)(void*,int); /* Resize an allocation */ 1045 int (*xSize)(void*); /* Return the size of an allocation */ 1046 int (*xRoundup)(int); /* Round up request size to allocation size */ 1047 int (*xInit)(void*); /* Initialize the memory allocator */ 1048 void (*xShutdown)(void*); /* Deinitialize the memory allocator */ 1049 void *pAppData; /* Argument to xInit() and xShutdown() */ 1050}; 1051 1052/* 1053** CAPI3REF: Configuration Options 1054** EXPERIMENTAL 1055** 1056** These constants are the available integer configuration options that 1057** can be passed as the first argument to the [sqlite3_config()] interface. 1058** 1059** New configuration options may be added in future releases of SQLite. 1060** Existing configuration options might be discontinued. Applications 1061** should check the return code from [sqlite3_config()] to make sure that 1062** the call worked. The [sqlite3_config()] interface will return a 1063** non-zero [error code] if a discontinued or unsupported configuration option 1064** is invoked. 1065** 1066** <dl> 1067** <dt>SQLITE_CONFIG_SINGLETHREAD</dt> 1068** <dd>There are no arguments to this option. ^This option sets the 1069** [threading mode] to Single-thread. In other words, it disables 1070** all mutexing and puts SQLite into a mode where it can only be used 1071** by a single thread. ^If SQLite is compiled with 1072** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1073** it is not possible to change the [threading mode] from its default 1074** value of Single-thread and so [sqlite3_config()] will return 1075** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD 1076** configuration option.</dd> 1077** 1078** <dt>SQLITE_CONFIG_MULTITHREAD</dt> 1079** <dd>There are no arguments to this option. ^This option sets the 1080** [threading mode] to Multi-thread. In other words, it disables 1081** mutexing on [database connection] and [prepared statement] objects. 1082** The application is responsible for serializing access to 1083** [database connections] and [prepared statements]. But other mutexes 1084** are enabled so that SQLite will be safe to use in a multi-threaded 1085** environment as long as no two threads attempt to use the same 1086** [database connection] at the same time. ^If SQLite is compiled with 1087** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1088** it is not possible to set the Multi-thread [threading mode] and 1089** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1090** SQLITE_CONFIG_MULTITHREAD configuration option.</dd> 1091** 1092** <dt>SQLITE_CONFIG_SERIALIZED</dt> 1093** <dd>There are no arguments to this option. ^This option sets the 1094** [threading mode] to Serialized. In other words, this option enables 1095** all mutexes including the recursive 1096** mutexes on [database connection] and [prepared statement] objects. 1097** In this mode (which is the default when SQLite is compiled with 1098** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access 1099** to [database connections] and [prepared statements] so that the 1100** application is free to use the same [database connection] or the 1101** same [prepared statement] in different threads at the same time. 1102** ^If SQLite is compiled with 1103** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1104** it is not possible to set the Serialized [threading mode] and 1105** [sqlite3_config()] will return [SQLITE_ERROR] if called with the 1106** SQLITE_CONFIG_SERIALIZED configuration option.</dd> 1107** 1108** <dt>SQLITE_CONFIG_MALLOC</dt> 1109** <dd> ^(This option takes a single argument which is a pointer to an 1110** instance of the [sqlite3_mem_methods] structure. The argument specifies 1111** alternative low-level memory allocation routines to be used in place of 1112** the memory allocation routines built into SQLite.)^ ^SQLite makes 1113** its own private copy of the content of the [sqlite3_mem_methods] structure 1114** before the [sqlite3_config()] call returns.</dd> 1115** 1116** <dt>SQLITE_CONFIG_GETMALLOC</dt> 1117** <dd> ^(This option takes a single argument which is a pointer to an 1118** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] 1119** structure is filled with the currently defined memory allocation routines.)^ 1120** This option can be used to overload the default memory allocation 1121** routines with a wrapper that simulations memory allocation failure or 1122** tracks memory usage, for example. </dd> 1123** 1124** <dt>SQLITE_CONFIG_MEMSTATUS</dt> 1125** <dd> ^This option takes single argument of type int, interpreted as a 1126** boolean, which enables or disables the collection of memory allocation 1127** statistics. ^(When memory allocation statistics are disabled, the 1128** following SQLite interfaces become non-operational: 1129** <ul> 1130** <li> [sqlite3_memory_used()] 1131** <li> [sqlite3_memory_highwater()] 1132** <li> [sqlite3_soft_heap_limit()] 1133** <li> [sqlite3_status()] 1134** </ul>)^ 1135** ^Memory allocation statistics are enabled by default unless SQLite is 1136** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory 1137** allocation statistics are disabled by default. 1138** </dd> 1139** 1140** <dt>SQLITE_CONFIG_SCRATCH</dt> 1141** <dd> ^This option specifies a static memory buffer that SQLite can use for 1142** scratch memory. There are three arguments: A pointer an 8-byte 1143** aligned memory buffer from which the scrach allocations will be 1144** drawn, the size of each scratch allocation (sz), 1145** and the maximum number of scratch allocations (N). The sz 1146** argument must be a multiple of 16. The sz parameter should be a few bytes 1147** larger than the actual scratch space required due to internal overhead. 1148** The first argument must be a pointer to an 8-byte aligned buffer 1149** of at least sz*N bytes of memory. 1150** ^SQLite will use no more than one scratch buffer per thread. So 1151** N should be set to the expected maximum number of threads. ^SQLite will 1152** never require a scratch buffer that is more than 6 times the database 1153** page size. ^If SQLite needs needs additional scratch memory beyond 1154** what is provided by this configuration option, then 1155** [sqlite3_malloc()] will be used to obtain the memory needed.</dd> 1156** 1157** <dt>SQLITE_CONFIG_PAGECACHE</dt> 1158** <dd> ^This option specifies a static memory buffer that SQLite can use for 1159** the database page cache with the default page cache implemenation. 1160** This configuration should not be used if an application-define page 1161** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. 1162** There are three arguments to this option: A pointer to 8-byte aligned 1163** memory, the size of each page buffer (sz), and the number of pages (N). 1164** The sz argument should be the size of the largest database page 1165** (a power of two between 512 and 32768) plus a little extra for each 1166** page header. ^The page header size is 20 to 40 bytes depending on 1167** the host architecture. ^It is harmless, apart from the wasted memory, 1168** to make sz a little too large. The first 1169** argument should point to an allocation of at least sz*N bytes of memory. 1170** ^SQLite will use the memory provided by the first argument to satisfy its 1171** memory needs for the first N pages that it adds to cache. ^If additional 1172** page cache memory is needed beyond what is provided by this option, then 1173** SQLite goes to [sqlite3_malloc()] for the additional storage space. 1174** ^The implementation might use one or more of the N buffers to hold 1175** memory accounting information. The pointer in the first argument must 1176** be aligned to an 8-byte boundary or subsequent behavior of SQLite 1177** will be undefined.</dd> 1178** 1179** <dt>SQLITE_CONFIG_HEAP</dt> 1180** <dd> ^This option specifies a static memory buffer that SQLite will use 1181** for all of its dynamic memory allocation needs beyond those provided 1182** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. 1183** There are three arguments: An 8-byte aligned pointer to the memory, 1184** the number of bytes in the memory buffer, and the minimum allocation size. 1185** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts 1186** to using its default memory allocator (the system malloc() implementation), 1187** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. ^If the 1188** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or 1189** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory 1190** allocator is engaged to handle all of SQLites memory allocation needs. 1191** The first pointer (the memory pointer) must be aligned to an 8-byte 1192** boundary or subsequent behavior of SQLite will be undefined.</dd> 1193** 1194** <dt>SQLITE_CONFIG_MUTEX</dt> 1195** <dd> ^(This option takes a single argument which is a pointer to an 1196** instance of the [sqlite3_mutex_methods] structure. The argument specifies 1197** alternative low-level mutex routines to be used in place 1198** the mutex routines built into SQLite.)^ ^SQLite makes a copy of the 1199** content of the [sqlite3_mutex_methods] structure before the call to 1200** [sqlite3_config()] returns. ^If SQLite is compiled with 1201** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1202** the entire mutexing subsystem is omitted from the build and hence calls to 1203** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will 1204** return [SQLITE_ERROR].</dd> 1205** 1206** <dt>SQLITE_CONFIG_GETMUTEX</dt> 1207** <dd> ^(This option takes a single argument which is a pointer to an 1208** instance of the [sqlite3_mutex_methods] structure. The 1209** [sqlite3_mutex_methods] 1210** structure is filled with the currently defined mutex routines.)^ 1211** This option can be used to overload the default mutex allocation 1212** routines with a wrapper used to track mutex usage for performance 1213** profiling or testing, for example. ^If SQLite is compiled with 1214** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then 1215** the entire mutexing subsystem is omitted from the build and hence calls to 1216** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will 1217** return [SQLITE_ERROR].</dd> 1218** 1219** <dt>SQLITE_CONFIG_LOOKASIDE</dt> 1220** <dd> ^(This option takes two arguments that determine the default 1221** memory allocation for the lookaside memory allocator on each 1222** [database connection]. The first argument is the 1223** size of each lookaside buffer slot and the second is the number of 1224** slots allocated to each database connection.)^ ^(This option sets the 1225** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE] 1226** verb to [sqlite3_db_config()] can be used to change the lookaside 1227** configuration on individual connections.)^ </dd> 1228** 1229** <dt>SQLITE_CONFIG_PCACHE</dt> 1230** <dd> ^(This option takes a single argument which is a pointer to 1231** an [sqlite3_pcache_methods] object. This object specifies the interface 1232** to a custom page cache implementation.)^ ^SQLite makes a copy of the 1233** object and uses it for page cache memory allocations.</dd> 1234** 1235** <dt>SQLITE_CONFIG_GETPCACHE</dt> 1236** <dd> ^(This option takes a single argument which is a pointer to an 1237** [sqlite3_pcache_methods] object. SQLite copies of the current 1238** page cache implementation into that object.)^ </dd> 1239** 1240** </dl> 1241*/ 1242#define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ 1243#define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ 1244#define SQLITE_CONFIG_SERIALIZED 3 /* nil */ 1245#define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ 1246#define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ 1247#define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ 1248#define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ 1249#define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ 1250#define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ 1251#define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ 1252#define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ 1253/* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 1254#define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ 1255#define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ 1256#define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ 1257 1258/* 1259** CAPI3REF: Configuration Options 1260** EXPERIMENTAL 1261** 1262** These constants are the available integer configuration options that 1263** can be passed as the second argument to the [sqlite3_db_config()] interface. 1264** 1265** New configuration options may be added in future releases of SQLite. 1266** Existing configuration options might be discontinued. Applications 1267** should check the return code from [sqlite3_db_config()] to make sure that 1268** the call worked. ^The [sqlite3_db_config()] interface will return a 1269** non-zero [error code] if a discontinued or unsupported configuration option 1270** is invoked. 1271** 1272** <dl> 1273** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt> 1274** <dd> ^This option takes three additional arguments that determine the 1275** [lookaside memory allocator] configuration for the [database connection]. 1276** ^The first argument (the third parameter to [sqlite3_db_config()] is a 1277** pointer to an memory buffer to use for lookaside memory. 1278** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb 1279** may be NULL in which case SQLite will allocate the 1280** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the 1281** size of each lookaside buffer slot. ^The third argument is the number of 1282** slots. The size of the buffer in the first argument must be greater than 1283** or equal to the product of the second and third arguments. The buffer 1284** must be aligned to an 8-byte boundary. ^If the second argument to 1285** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally 1286** rounded down to the next smaller 1287** multiple of 8. See also: [SQLITE_CONFIG_LOOKASIDE]</dd> 1288** 1289** </dl> 1290*/ 1291#define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ 1292 1293 1294/* 1295** CAPI3REF: Enable Or Disable Extended Result Codes 1296** 1297** ^The sqlite3_extended_result_codes() routine enables or disables the 1298** [extended result codes] feature of SQLite. ^The extended result 1299** codes are disabled by default for historical compatibility. 1300*/ 1301int sqlite3_extended_result_codes(sqlite3*, int onoff); 1302 1303/* 1304** CAPI3REF: Last Insert Rowid 1305** 1306** ^Each entry in an SQLite table has a unique 64-bit signed 1307** integer key called the [ROWID | "rowid"]. ^The rowid is always available 1308** as an undeclared column named ROWID, OID, or _ROWID_ as long as those 1309** names are not also used by explicitly declared columns. ^If 1310** the table has a column of type [INTEGER PRIMARY KEY] then that column 1311** is another alias for the rowid. 1312** 1313** ^This routine returns the [rowid] of the most recent 1314** successful [INSERT] into the database from the [database connection] 1315** in the first argument. ^If no successful [INSERT]s 1316** have ever occurred on that database connection, zero is returned. 1317** 1318** ^(If an [INSERT] occurs within a trigger, then the [rowid] of the inserted 1319** row is returned by this routine as long as the trigger is running. 1320** But once the trigger terminates, the value returned by this routine 1321** reverts to the last value inserted before the trigger fired.)^ 1322** 1323** ^An [INSERT] that fails due to a constraint violation is not a 1324** successful [INSERT] and does not change the value returned by this 1325** routine. ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, 1326** and INSERT OR ABORT make no changes to the return value of this 1327** routine when their insertion fails. ^(When INSERT OR REPLACE 1328** encounters a constraint violation, it does not fail. The 1329** INSERT continues to completion after deleting rows that caused 1330** the constraint problem so INSERT OR REPLACE will always change 1331** the return value of this interface.)^ 1332** 1333** ^For the purposes of this routine, an [INSERT] is considered to 1334** be successful even if it is subsequently rolled back. 1335** 1336** This function is accessible to SQL statements via the 1337** [last_insert_rowid() SQL function]. 1338** 1339** If a separate thread performs a new [INSERT] on the same 1340** database connection while the [sqlite3_last_insert_rowid()] 1341** function is running and thus changes the last insert [rowid], 1342** then the value returned by [sqlite3_last_insert_rowid()] is 1343** unpredictable and might not equal either the old or the new 1344** last insert [rowid]. 1345*/ 1346sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); 1347 1348/* 1349** CAPI3REF: Count The Number Of Rows Modified 1350** 1351** ^This function returns the number of database rows that were changed 1352** or inserted or deleted by the most recently completed SQL statement 1353** on the [database connection] specified by the first parameter. 1354** ^(Only changes that are directly specified by the [INSERT], [UPDATE], 1355** or [DELETE] statement are counted. Auxiliary changes caused by 1356** triggers or [foreign key actions] are not counted.)^ Use the 1357** [sqlite3_total_changes()] function to find the total number of changes 1358** including changes caused by triggers and foreign key actions. 1359** 1360** ^Changes to a view that are simulated by an [INSTEAD OF trigger] 1361** are not counted. Only real table changes are counted. 1362** 1363** ^(A "row change" is a change to a single row of a single table 1364** caused by an INSERT, DELETE, or UPDATE statement. Rows that 1365** are changed as side effects of [REPLACE] constraint resolution, 1366** rollback, ABORT processing, [DROP TABLE], or by any other 1367** mechanisms do not count as direct row changes.)^ 1368** 1369** A "trigger context" is a scope of execution that begins and 1370** ends with the script of a [CREATE TRIGGER | trigger]. 1371** Most SQL statements are 1372** evaluated outside of any trigger. This is the "top level" 1373** trigger context. If a trigger fires from the top level, a 1374** new trigger context is entered for the duration of that one 1375** trigger. Subtriggers create subcontexts for their duration. 1376** 1377** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does 1378** not create a new trigger context. 1379** 1380** ^This function returns the number of direct row changes in the 1381** most recent INSERT, UPDATE, or DELETE statement within the same 1382** trigger context. 1383** 1384** ^Thus, when called from the top level, this function returns the 1385** number of changes in the most recent INSERT, UPDATE, or DELETE 1386** that also occurred at the top level. ^(Within the body of a trigger, 1387** the sqlite3_changes() interface can be called to find the number of 1388** changes in the most recently completed INSERT, UPDATE, or DELETE 1389** statement within the body of the same trigger. 1390** However, the number returned does not include changes 1391** caused by subtriggers since those have their own context.)^ 1392** 1393** See also the [sqlite3_total_changes()] interface, the 1394** [count_changes pragma], and the [changes() SQL function]. 1395** 1396** If a separate thread makes changes on the same database connection 1397** while [sqlite3_changes()] is running then the value returned 1398** is unpredictable and not meaningful. 1399*/ 1400int sqlite3_changes(sqlite3*); 1401 1402/* 1403** CAPI3REF: Total Number Of Rows Modified 1404** 1405** ^This function returns the number of row changes caused by [INSERT], 1406** [UPDATE] or [DELETE] statements since the [database connection] was opened. 1407** ^(The count returned by sqlite3_total_changes() includes all changes 1408** from all [CREATE TRIGGER | trigger] contexts and changes made by 1409** [foreign key actions]. However, 1410** the count does not include changes used to implement [REPLACE] constraints, 1411** do rollbacks or ABORT processing, or [DROP TABLE] processing. The 1412** count does not include rows of views that fire an [INSTEAD OF trigger], 1413** though if the INSTEAD OF trigger makes changes of its own, those changes 1414** are counted.)^ 1415** ^The sqlite3_total_changes() function counts the changes as soon as 1416** the statement that makes them is completed (when the statement handle 1417** is passed to [sqlite3_reset()] or [sqlite3_finalize()]). 1418** 1419** See also the [sqlite3_changes()] interface, the 1420** [count_changes pragma], and the [total_changes() SQL function]. 1421** 1422** If a separate thread makes changes on the same database connection 1423** while [sqlite3_total_changes()] is running then the value 1424** returned is unpredictable and not meaningful. 1425*/ 1426int sqlite3_total_changes(sqlite3*); 1427 1428/* 1429** CAPI3REF: Interrupt A Long-Running Query 1430** 1431** ^This function causes any pending database operation to abort and 1432** return at its earliest opportunity. This routine is typically 1433** called in response to a user action such as pressing "Cancel" 1434** or Ctrl-C where the user wants a long query operation to halt 1435** immediately. 1436** 1437** ^It is safe to call this routine from a thread different from the 1438** thread that is currently running the database operation. But it 1439** is not safe to call this routine with a [database connection] that 1440** is closed or might close before sqlite3_interrupt() returns. 1441** 1442** ^If an SQL operation is very nearly finished at the time when 1443** sqlite3_interrupt() is called, then it might not have an opportunity 1444** to be interrupted and might continue to completion. 1445** 1446** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. 1447** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE 1448** that is inside an explicit transaction, then the entire transaction 1449** will be rolled back automatically. 1450** 1451** ^The sqlite3_interrupt(D) call is in effect until all currently running 1452** SQL statements on [database connection] D complete. ^Any new SQL statements 1453** that are started after the sqlite3_interrupt() call and before the 1454** running statements reaches zero are interrupted as if they had been 1455** running prior to the sqlite3_interrupt() call. ^New SQL statements 1456** that are started after the running statement count reaches zero are 1457** not effected by the sqlite3_interrupt(). 1458** ^A call to sqlite3_interrupt(D) that occurs when there are no running 1459** SQL statements is a no-op and has no effect on SQL statements 1460** that are started after the sqlite3_interrupt() call returns. 1461** 1462** If the database connection closes while [sqlite3_interrupt()] 1463** is running then bad things will likely happen. 1464*/ 1465void sqlite3_interrupt(sqlite3*); 1466 1467/* 1468** CAPI3REF: Determine If An SQL Statement Is Complete 1469** 1470** These routines are useful during command-line input to determine if the 1471** currently entered text seems to form a complete SQL statement or 1472** if additional input is needed before sending the text into 1473** SQLite for parsing. ^These routines return 1 if the input string 1474** appears to be a complete SQL statement. ^A statement is judged to be 1475** complete if it ends with a semicolon token and is not a prefix of a 1476** well-formed CREATE TRIGGER statement. ^Semicolons that are embedded within 1477** string literals or quoted identifier names or comments are not 1478** independent tokens (they are part of the token in which they are 1479** embedded) and thus do not count as a statement terminator. ^Whitespace 1480** and comments that follow the final semicolon are ignored. 1481** 1482** ^These routines return 0 if the statement is incomplete. ^If a 1483** memory allocation fails, then SQLITE_NOMEM is returned. 1484** 1485** ^These routines do not parse the SQL statements thus 1486** will not detect syntactically incorrect SQL. 1487** 1488** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 1489** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked 1490** automatically by sqlite3_complete16(). If that initialization fails, 1491** then the return value from sqlite3_complete16() will be non-zero 1492** regardless of whether or not the input SQL is complete.)^ 1493** 1494** The input to [sqlite3_complete()] must be a zero-terminated 1495** UTF-8 string. 1496** 1497** The input to [sqlite3_complete16()] must be a zero-terminated 1498** UTF-16 string in native byte order. 1499*/ 1500int sqlite3_complete(const char *sql); 1501int sqlite3_complete16(const void *sql); 1502 1503/* 1504** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors 1505** 1506** ^This routine sets a callback function that might be invoked whenever 1507** an attempt is made to open a database table that another thread 1508** or process has locked. 1509** 1510** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] 1511** is returned immediately upon encountering the lock. ^If the busy callback 1512** is not NULL, then the callback might be invoked with two arguments. 1513** 1514** ^The first argument to the busy handler is a copy of the void* pointer which 1515** is the third argument to sqlite3_busy_handler(). ^The second argument to 1516** the busy handler callback is the number of times that the busy handler has 1517** been invoked for this locking event. ^If the 1518** busy callback returns 0, then no additional attempts are made to 1519** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. 1520** ^If the callback returns non-zero, then another attempt 1521** is made to open the database for reading and the cycle repeats. 1522** 1523** The presence of a busy handler does not guarantee that it will be invoked 1524** when there is lock contention. ^If SQLite determines that invoking the busy 1525** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] 1526** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. 1527** Consider a scenario where one process is holding a read lock that 1528** it is trying to promote to a reserved lock and 1529** a second process is holding a reserved lock that it is trying 1530** to promote to an exclusive lock. The first process cannot proceed 1531** because it is blocked by the second and the second process cannot 1532** proceed because it is blocked by the first. If both processes 1533** invoke the busy handlers, neither will make any progress. Therefore, 1534** SQLite returns [SQLITE_BUSY] for the first process, hoping that this 1535** will induce the first process to release its read lock and allow 1536** the second process to proceed. 1537** 1538** ^The default busy callback is NULL. 1539** 1540** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] 1541** when SQLite is in the middle of a large transaction where all the 1542** changes will not fit into the in-memory cache. SQLite will 1543** already hold a RESERVED lock on the database file, but it needs 1544** to promote this lock to EXCLUSIVE so that it can spill cache 1545** pages into the database file without harm to concurrent 1546** readers. ^If it is unable to promote the lock, then the in-memory 1547** cache will be left in an inconsistent state and so the error 1548** code is promoted from the relatively benign [SQLITE_BUSY] to 1549** the more severe [SQLITE_IOERR_BLOCKED]. ^This error code promotion 1550** forces an automatic rollback of the changes. See the 1551** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError"> 1552** CorruptionFollowingBusyError</a> wiki page for a discussion of why 1553** this is important. 1554** 1555** ^(There can only be a single busy handler defined for each 1556** [database connection]. Setting a new busy handler clears any 1557** previously set handler.)^ ^Note that calling [sqlite3_busy_timeout()] 1558** will also set or clear the busy handler. 1559** 1560** The busy callback should not take any actions which modify the 1561** database connection that invoked the busy handler. Any such actions 1562** result in undefined behavior. 1563** 1564** A busy handler must not close the database connection 1565** or [prepared statement] that invoked the busy handler. 1566*/ 1567int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); 1568 1569/* 1570** CAPI3REF: Set A Busy Timeout 1571** 1572** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps 1573** for a specified amount of time when a table is locked. ^The handler 1574** will sleep multiple times until at least "ms" milliseconds of sleeping 1575** have accumulated. ^After at least "ms" milliseconds of sleeping, 1576** the handler returns 0 which causes [sqlite3_step()] to return 1577** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. 1578** 1579** ^Calling this routine with an argument less than or equal to zero 1580** turns off all busy handlers. 1581** 1582** ^(There can only be a single busy handler for a particular 1583** [database connection] any any given moment. If another busy handler 1584** was defined (using [sqlite3_busy_handler()]) prior to calling 1585** this routine, that other busy handler is cleared.)^ 1586*/ 1587int sqlite3_busy_timeout(sqlite3*, int ms); 1588 1589/* 1590** CAPI3REF: Convenience Routines For Running Queries 1591** 1592** Definition: A <b>result table</b> is memory data structure created by the 1593** [sqlite3_get_table()] interface. A result table records the 1594** complete query results from one or more queries. 1595** 1596** The table conceptually has a number of rows and columns. But 1597** these numbers are not part of the result table itself. These 1598** numbers are obtained separately. Let N be the number of rows 1599** and M be the number of columns. 1600** 1601** A result table is an array of pointers to zero-terminated UTF-8 strings. 1602** There are (N+1)*M elements in the array. The first M pointers point 1603** to zero-terminated strings that contain the names of the columns. 1604** The remaining entries all point to query results. NULL values result 1605** in NULL pointers. All other values are in their UTF-8 zero-terminated 1606** string representation as returned by [sqlite3_column_text()]. 1607** 1608** A result table might consist of one or more memory allocations. 1609** It is not safe to pass a result table directly to [sqlite3_free()]. 1610** A result table should be deallocated using [sqlite3_free_table()]. 1611** 1612** As an example of the result table format, suppose a query result 1613** is as follows: 1614** 1615** <blockquote><pre> 1616** Name | Age 1617** ----------------------- 1618** Alice | 43 1619** Bob | 28 1620** Cindy | 21 1621** </pre></blockquote> 1622** 1623** There are two column (M==2) and three rows (N==3). Thus the 1624** result table has 8 entries. Suppose the result table is stored 1625** in an array names azResult. Then azResult holds this content: 1626** 1627** <blockquote><pre> 1628** azResult[0] = "Name"; 1629** azResult[1] = "Age"; 1630** azResult[2] = "Alice"; 1631** azResult[3] = "43"; 1632** azResult[4] = "Bob"; 1633** azResult[5] = "28"; 1634** azResult[6] = "Cindy"; 1635** azResult[7] = "21"; 1636** </pre></blockquote> 1637** 1638** ^The sqlite3_get_table() function evaluates one or more 1639** semicolon-separated SQL statements in the zero-terminated UTF-8 1640** string of its 2nd parameter and returns a result table to the 1641** pointer given in its 3rd parameter. 1642** 1643** After the application has finished with the result from sqlite3_get_table(), 1644** it should pass the result table pointer to sqlite3_free_table() in order to 1645** release the memory that was malloced. Because of the way the 1646** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling 1647** function must not try to call [sqlite3_free()] directly. Only 1648** [sqlite3_free_table()] is able to release the memory properly and safely. 1649** 1650** ^(The sqlite3_get_table() interface is implemented as a wrapper around 1651** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access 1652** to any internal data structures of SQLite. It uses only the public 1653** interface defined here. As a consequence, errors that occur in the 1654** wrapper layer outside of the internal [sqlite3_exec()] call are not 1655** reflected in subsequent calls to [sqlite3_errcode()] or 1656** [sqlite3_errmsg()].)^ 1657*/ 1658int sqlite3_get_table( 1659 sqlite3 *db, /* An open database */ 1660 const char *zSql, /* SQL to be evaluated */ 1661 char ***pazResult, /* Results of the query */ 1662 int *pnRow, /* Number of result rows written here */ 1663 int *pnColumn, /* Number of result columns written here */ 1664 char **pzErrmsg /* Error msg written here */ 1665); 1666void sqlite3_free_table(char **result); 1667 1668/* 1669** CAPI3REF: Formatted String Printing Functions 1670** 1671** These routines are work-alikes of the "printf()" family of functions 1672** from the standard C library. 1673** 1674** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their 1675** results into memory obtained from [sqlite3_malloc()]. 1676** The strings returned by these two routines should be 1677** released by [sqlite3_free()]. ^Both routines return a 1678** NULL pointer if [sqlite3_malloc()] is unable to allocate enough 1679** memory to hold the resulting string. 1680** 1681** ^(In sqlite3_snprintf() routine is similar to "snprintf()" from 1682** the standard C library. The result is written into the 1683** buffer supplied as the second parameter whose size is given by 1684** the first parameter. Note that the order of the 1685** first two parameters is reversed from snprintf().)^ This is an 1686** historical accident that cannot be fixed without breaking 1687** backwards compatibility. ^(Note also that sqlite3_snprintf() 1688** returns a pointer to its buffer instead of the number of 1689** characters actually written into the buffer.)^ We admit that 1690** the number of characters written would be a more useful return 1691** value but we cannot change the implementation of sqlite3_snprintf() 1692** now without breaking compatibility. 1693** 1694** ^As long as the buffer size is greater than zero, sqlite3_snprintf() 1695** guarantees that the buffer is always zero-terminated. ^The first 1696** parameter "n" is the total size of the buffer, including space for 1697** the zero terminator. So the longest string that can be completely 1698** written will be n-1 characters. 1699** 1700** These routines all implement some additional formatting 1701** options that are useful for constructing SQL statements. 1702** All of the usual printf() formatting options apply. In addition, there 1703** is are "%q", "%Q", and "%z" options. 1704** 1705** ^(The %q option works like %s in that it substitutes a null-terminated 1706** string from the argument list. But %q also doubles every '\'' character. 1707** %q is designed for use inside a string literal.)^ By doubling each '\'' 1708** character it escapes that character and allows it to be inserted into 1709** the string. 1710** 1711** For example, assume the string variable zText contains text as follows: 1712** 1713** <blockquote><pre> 1714** char *zText = "It's a happy day!"; 1715** </pre></blockquote> 1716** 1717** One can use this text in an SQL statement as follows: 1718** 1719** <blockquote><pre> 1720** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText); 1721** sqlite3_exec(db, zSQL, 0, 0, 0); 1722** sqlite3_free(zSQL); 1723** </pre></blockquote> 1724** 1725** Because the %q format string is used, the '\'' character in zText 1726** is escaped and the SQL generated is as follows: 1727** 1728** <blockquote><pre> 1729** INSERT INTO table1 VALUES('It''s a happy day!') 1730** </pre></blockquote> 1731** 1732** This is correct. Had we used %s instead of %q, the generated SQL 1733** would have looked like this: 1734** 1735** <blockquote><pre> 1736** INSERT INTO table1 VALUES('It's a happy day!'); 1737** </pre></blockquote> 1738** 1739** This second example is an SQL syntax error. As a general rule you should 1740** always use %q instead of %s when inserting text into a string literal. 1741** 1742** ^(The %Q option works like %q except it also adds single quotes around 1743** the outside of the total string. Additionally, if the parameter in the 1744** argument list is a NULL pointer, %Q substitutes the text "NULL" (without 1745** single quotes).)^ So, for example, one could say: 1746** 1747** <blockquote><pre> 1748** char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText); 1749** sqlite3_exec(db, zSQL, 0, 0, 0); 1750** sqlite3_free(zSQL); 1751** </pre></blockquote> 1752** 1753** The code above will render a correct SQL statement in the zSQL 1754** variable even if the zText variable is a NULL pointer. 1755** 1756** ^(The "%z" formatting option works like "%s" but with the 1757** addition that after the string has been read and copied into 1758** the result, [sqlite3_free()] is called on the input string.)^ 1759*/ 1760char *sqlite3_mprintf(const char*,...); 1761char *sqlite3_vmprintf(const char*, va_list); 1762char *sqlite3_snprintf(int,char*,const char*, ...); 1763 1764/* 1765** CAPI3REF: Memory Allocation Subsystem 1766** 1767** The SQLite core uses these three routines for all of its own 1768** internal memory allocation needs. "Core" in the previous sentence 1769** does not include operating-system specific VFS implementation. The 1770** Windows VFS uses native malloc() and free() for some operations. 1771** 1772** ^The sqlite3_malloc() routine returns a pointer to a block 1773** of memory at least N bytes in length, where N is the parameter. 1774** ^If sqlite3_malloc() is unable to obtain sufficient free 1775** memory, it returns a NULL pointer. ^If the parameter N to 1776** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns 1777** a NULL pointer. 1778** 1779** ^Calling sqlite3_free() with a pointer previously returned 1780** by sqlite3_malloc() or sqlite3_realloc() releases that memory so 1781** that it might be reused. ^The sqlite3_free() routine is 1782** a no-op if is called with a NULL pointer. Passing a NULL pointer 1783** to sqlite3_free() is harmless. After being freed, memory 1784** should neither be read nor written. Even reading previously freed 1785** memory might result in a segmentation fault or other severe error. 1786** Memory corruption, a segmentation fault, or other severe error 1787** might result if sqlite3_free() is called with a non-NULL pointer that 1788** was not obtained from sqlite3_malloc() or sqlite3_realloc(). 1789** 1790** ^(The sqlite3_realloc() interface attempts to resize a 1791** prior memory allocation to be at least N bytes, where N is the 1792** second parameter. The memory allocation to be resized is the first 1793** parameter.)^ ^ If the first parameter to sqlite3_realloc() 1794** is a NULL pointer then its behavior is identical to calling 1795** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). 1796** ^If the second parameter to sqlite3_realloc() is zero or 1797** negative then the behavior is exactly the same as calling 1798** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). 1799** ^sqlite3_realloc() returns a pointer to a memory allocation 1800** of at least N bytes in size or NULL if sufficient memory is unavailable. 1801** ^If M is the size of the prior allocation, then min(N,M) bytes 1802** of the prior allocation are copied into the beginning of buffer returned 1803** by sqlite3_realloc() and the prior allocation is freed. 1804** ^If sqlite3_realloc() returns NULL, then the prior allocation 1805** is not freed. 1806** 1807** ^The memory returned by sqlite3_malloc() and sqlite3_realloc() 1808** is always aligned to at least an 8 byte boundary. 1809** 1810** In SQLite version 3.5.0 and 3.5.1, it was possible to define 1811** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in 1812** implementation of these routines to be omitted. That capability 1813** is no longer provided. Only built-in memory allocators can be used. 1814** 1815** The Windows OS interface layer calls 1816** the system malloc() and free() directly when converting 1817** filenames between the UTF-8 encoding used by SQLite 1818** and whatever filename encoding is used by the particular Windows 1819** installation. Memory allocation errors are detected, but 1820** they are reported back as [SQLITE_CANTOPEN] or 1821** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. 1822** 1823** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] 1824** must be either NULL or else pointers obtained from a prior 1825** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have 1826** not yet been released. 1827** 1828** The application must not read or write any part of 1829** a block of memory after it has been released using 1830** [sqlite3_free()] or [sqlite3_realloc()]. 1831*/ 1832void *sqlite3_malloc(int); 1833void *sqlite3_realloc(void*, int); 1834void sqlite3_free(void*); 1835 1836/* 1837** CAPI3REF: Memory Allocator Statistics 1838** 1839** SQLite provides these two interfaces for reporting on the status 1840** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] 1841** routines, which form the built-in memory allocation subsystem. 1842** 1843** ^The [sqlite3_memory_used()] routine returns the number of bytes 1844** of memory currently outstanding (malloced but not freed). 1845** ^The [sqlite3_memory_highwater()] routine returns the maximum 1846** value of [sqlite3_memory_used()] since the high-water mark 1847** was last reset. ^The values returned by [sqlite3_memory_used()] and 1848** [sqlite3_memory_highwater()] include any overhead 1849** added by SQLite in its implementation of [sqlite3_malloc()], 1850** but not overhead added by the any underlying system library 1851** routines that [sqlite3_malloc()] may call. 1852** 1853** ^The memory high-water mark is reset to the current value of 1854** [sqlite3_memory_used()] if and only if the parameter to 1855** [sqlite3_memory_highwater()] is true. ^The value returned 1856** by [sqlite3_memory_highwater(1)] is the high-water mark 1857** prior to the reset. 1858*/ 1859sqlite3_int64 sqlite3_memory_used(void); 1860sqlite3_int64 sqlite3_memory_highwater(int resetFlag); 1861 1862/* 1863** CAPI3REF: Pseudo-Random Number Generator 1864** 1865** SQLite contains a high-quality pseudo-random number generator (PRNG) used to 1866** select random [ROWID | ROWIDs] when inserting new records into a table that 1867** already uses the largest possible [ROWID]. The PRNG is also used for 1868** the build-in random() and randomblob() SQL functions. This interface allows 1869** applications to access the same PRNG for other purposes. 1870** 1871** ^A call to this routine stores N bytes of randomness into buffer P. 1872** 1873** ^The first time this routine is invoked (either internally or by 1874** the application) the PRNG is seeded using randomness obtained 1875** from the xRandomness method of the default [sqlite3_vfs] object. 1876** ^On all subsequent invocations, the pseudo-randomness is generated 1877** internally and without recourse to the [sqlite3_vfs] xRandomness 1878** method. 1879*/ 1880void sqlite3_randomness(int N, void *P); 1881 1882/* 1883** CAPI3REF: Compile-Time Authorization Callbacks 1884** 1885** ^This routine registers a authorizer callback with a particular 1886** [database connection], supplied in the first argument. 1887** ^The authorizer callback is invoked as SQL statements are being compiled 1888** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], 1889** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. ^At various 1890** points during the compilation process, as logic is being created 1891** to perform various actions, the authorizer callback is invoked to 1892** see if those actions are allowed. ^The authorizer callback should 1893** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the 1894** specific action but allow the SQL statement to continue to be 1895** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be 1896** rejected with an error. ^If the authorizer callback returns 1897** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] 1898** then the [sqlite3_prepare_v2()] or equivalent call that triggered 1899** the authorizer will fail with an error message. 1900** 1901** When the callback returns [SQLITE_OK], that means the operation 1902** requested is ok. ^When the callback returns [SQLITE_DENY], the 1903** [sqlite3_prepare_v2()] or equivalent call that triggered the 1904** authorizer will fail with an error message explaining that 1905** access is denied. 1906** 1907** ^The first parameter to the authorizer callback is a copy of the third 1908** parameter to the sqlite3_set_authorizer() interface. ^The second parameter 1909** to the callback is an integer [SQLITE_COPY | action code] that specifies 1910** the particular action to be authorized. ^The third through sixth parameters 1911** to the callback are zero-terminated strings that contain additional 1912** details about the action to be authorized. 1913** 1914** ^If the action code is [SQLITE_READ] 1915** and the callback returns [SQLITE_IGNORE] then the 1916** [prepared statement] statement is constructed to substitute 1917** a NULL value in place of the table column that would have 1918** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] 1919** return can be used to deny an untrusted user access to individual 1920** columns of a table. 1921** ^If the action code is [SQLITE_DELETE] and the callback returns 1922** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the 1923** [truncate optimization] is disabled and all rows are deleted individually. 1924** 1925** An authorizer is used when [sqlite3_prepare | preparing] 1926** SQL statements from an untrusted source, to ensure that the SQL statements 1927** do not try to access data they are not allowed to see, or that they do not 1928** try to execute malicious statements that damage the database. For 1929** example, an application may allow a user to enter arbitrary 1930** SQL queries for evaluation by a database. But the application does 1931** not want the user to be able to make arbitrary changes to the 1932** database. An authorizer could then be put in place while the 1933** user-entered SQL is being [sqlite3_prepare | prepared] that 1934** disallows everything except [SELECT] statements. 1935** 1936** Applications that need to process SQL from untrusted sources 1937** might also consider lowering resource limits using [sqlite3_limit()] 1938** and limiting database size using the [max_page_count] [PRAGMA] 1939** in addition to using an authorizer. 1940** 1941** ^(Only a single authorizer can be in place on a database connection 1942** at a time. Each call to sqlite3_set_authorizer overrides the 1943** previous call.)^ ^Disable the authorizer by installing a NULL callback. 1944** The authorizer is disabled by default. 1945** 1946** The authorizer callback must not do anything that will modify 1947** the database connection that invoked the authorizer callback. 1948** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 1949** database connections for the meaning of "modify" in this paragraph. 1950** 1951** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the 1952** statement might be re-prepared during [sqlite3_step()] due to a 1953** schema change. Hence, the application should ensure that the 1954** correct authorizer callback remains in place during the [sqlite3_step()]. 1955** 1956** ^Note that the authorizer callback is invoked only during 1957** [sqlite3_prepare()] or its variants. Authorization is not 1958** performed during statement evaluation in [sqlite3_step()], unless 1959** as stated in the previous paragraph, sqlite3_step() invokes 1960** sqlite3_prepare_v2() to reprepare a statement after a schema change. 1961*/ 1962int sqlite3_set_authorizer( 1963 sqlite3*, 1964 int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), 1965 void *pUserData 1966); 1967 1968/* 1969** CAPI3REF: Authorizer Return Codes 1970** 1971** The [sqlite3_set_authorizer | authorizer callback function] must 1972** return either [SQLITE_OK] or one of these two constants in order 1973** to signal SQLite whether or not the action is permitted. See the 1974** [sqlite3_set_authorizer | authorizer documentation] for additional 1975** information. 1976*/ 1977#define SQLITE_DENY 1 /* Abort the SQL statement with an error */ 1978#define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ 1979 1980/* 1981** CAPI3REF: Authorizer Action Codes 1982** 1983** The [sqlite3_set_authorizer()] interface registers a callback function 1984** that is invoked to authorize certain SQL statement actions. The 1985** second parameter to the callback is an integer code that specifies 1986** what action is being authorized. These are the integer action codes that 1987** the authorizer callback may be passed. 1988** 1989** These action code values signify what kind of operation is to be 1990** authorized. The 3rd and 4th parameters to the authorization 1991** callback function will be parameters or NULL depending on which of these 1992** codes is used as the second parameter. ^(The 5th parameter to the 1993** authorizer callback is the name of the database ("main", "temp", 1994** etc.) if applicable.)^ ^The 6th parameter to the authorizer callback 1995** is the name of the inner-most trigger or view that is responsible for 1996** the access attempt or NULL if this access attempt is directly from 1997** top-level SQL code. 1998*/ 1999/******************************************* 3rd ************ 4th ***********/ 2000#define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ 2001#define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ 2002#define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ 2003#define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ 2004#define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ 2005#define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ 2006#define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ 2007#define SQLITE_CREATE_VIEW 8 /* View Name NULL */ 2008#define SQLITE_DELETE 9 /* Table Name NULL */ 2009#define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ 2010#define SQLITE_DROP_TABLE 11 /* Table Name NULL */ 2011#define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ 2012#define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ 2013#define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ 2014#define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ 2015#define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ 2016#define SQLITE_DROP_VIEW 17 /* View Name NULL */ 2017#define SQLITE_INSERT 18 /* Table Name NULL */ 2018#define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ 2019#define SQLITE_READ 20 /* Table Name Column Name */ 2020#define SQLITE_SELECT 21 /* NULL NULL */ 2021#define SQLITE_TRANSACTION 22 /* Operation NULL */ 2022#define SQLITE_UPDATE 23 /* Table Name Column Name */ 2023#define SQLITE_ATTACH 24 /* Filename NULL */ 2024#define SQLITE_DETACH 25 /* Database Name NULL */ 2025#define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ 2026#define SQLITE_REINDEX 27 /* Index Name NULL */ 2027#define SQLITE_ANALYZE 28 /* Table Name NULL */ 2028#define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ 2029#define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ 2030#define SQLITE_FUNCTION 31 /* NULL Function Name */ 2031#define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ 2032#define SQLITE_COPY 0 /* No longer used */ 2033 2034/* 2035** CAPI3REF: Tracing And Profiling Functions 2036** EXPERIMENTAL 2037** 2038** These routines register callback functions that can be used for 2039** tracing and profiling the execution of SQL statements. 2040** 2041** ^The callback function registered by sqlite3_trace() is invoked at 2042** various times when an SQL statement is being run by [sqlite3_step()]. 2043** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the 2044** SQL statement text as the statement first begins executing. 2045** ^(Additional sqlite3_trace() callbacks might occur 2046** as each triggered subprogram is entered. The callbacks for triggers 2047** contain a UTF-8 SQL comment that identifies the trigger.)^ 2048** 2049** ^The callback function registered by sqlite3_profile() is invoked 2050** as each SQL statement finishes. ^The profile callback contains 2051** the original statement text and an estimate of wall-clock time 2052** of how long that statement took to run. 2053*/ 2054SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); 2055SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, 2056 void(*xProfile)(void*,const char*,sqlite3_uint64), void*); 2057 2058/* 2059** CAPI3REF: Query Progress Callbacks 2060** 2061** ^This routine configures a callback function - the 2062** progress callback - that is invoked periodically during long 2063** running calls to [sqlite3_exec()], [sqlite3_step()] and 2064** [sqlite3_get_table()]. An example use for this 2065** interface is to keep a GUI updated during a large query. 2066** 2067** ^If the progress callback returns non-zero, the operation is 2068** interrupted. This feature can be used to implement a 2069** "Cancel" button on a GUI progress dialog box. 2070** 2071** The progress handler must not do anything that will modify 2072** the database connection that invoked the progress handler. 2073** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 2074** database connections for the meaning of "modify" in this paragraph. 2075** 2076*/ 2077void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); 2078 2079/* 2080** CAPI3REF: Opening A New Database Connection 2081** 2082** ^These routines open an SQLite database file whose name is given by the 2083** filename argument. ^The filename argument is interpreted as UTF-8 for 2084** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte 2085** order for sqlite3_open16(). ^(A [database connection] handle is usually 2086** returned in *ppDb, even if an error occurs. The only exception is that 2087** if SQLite is unable to allocate memory to hold the [sqlite3] object, 2088** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] 2089** object.)^ ^(If the database is opened (and/or created) successfully, then 2090** [SQLITE_OK] is returned. Otherwise an [error code] is returned.)^ ^The 2091** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain 2092** an English language description of the error following a failure of any 2093** of the sqlite3_open() routines. 2094** 2095** ^The default encoding for the database will be UTF-8 if 2096** sqlite3_open() or sqlite3_open_v2() is called and 2097** UTF-16 in the native byte order if sqlite3_open16() is used. 2098** 2099** Whether or not an error occurs when it is opened, resources 2100** associated with the [database connection] handle should be released by 2101** passing it to [sqlite3_close()] when it is no longer required. 2102** 2103** The sqlite3_open_v2() interface works like sqlite3_open() 2104** except that it accepts two additional parameters for additional control 2105** over the new database connection. ^(The flags parameter to 2106** sqlite3_open_v2() can take one of 2107** the following three values, optionally combined with the 2108** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE], 2109** and/or [SQLITE_OPEN_PRIVATECACHE] flags:)^ 2110** 2111** <dl> 2112** ^(<dt>[SQLITE_OPEN_READONLY]</dt> 2113** <dd>The database is opened in read-only mode. If the database does not 2114** already exist, an error is returned.</dd>)^ 2115** 2116** ^(<dt>[SQLITE_OPEN_READWRITE]</dt> 2117** <dd>The database is opened for reading and writing if possible, or reading 2118** only if the file is write protected by the operating system. In either 2119** case the database must already exist, otherwise an error is returned.</dd>)^ 2120** 2121** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt> 2122** <dd>The database is opened for reading and writing, and is creates it if 2123** it does not already exist. This is the behavior that is always used for 2124** sqlite3_open() and sqlite3_open16().</dd>)^ 2125** </dl> 2126** 2127** If the 3rd parameter to sqlite3_open_v2() is not one of the 2128** combinations shown above or one of the combinations shown above combined 2129** with the [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], 2130** [SQLITE_OPEN_SHAREDCACHE] and/or [SQLITE_OPEN_SHAREDCACHE] flags, 2131** then the behavior is undefined. 2132** 2133** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection 2134** opens in the multi-thread [threading mode] as long as the single-thread 2135** mode has not been set at compile-time or start-time. ^If the 2136** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens 2137** in the serialized [threading mode] unless single-thread was 2138** previously selected at compile-time or start-time. 2139** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be 2140** eligible to use [shared cache mode], regardless of whether or not shared 2141** cache is enabled using [sqlite3_enable_shared_cache()]. ^The 2142** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not 2143** participate in [shared cache mode] even if it is enabled. 2144** 2145** ^If the filename is ":memory:", then a private, temporary in-memory database 2146** is created for the connection. ^This in-memory database will vanish when 2147** the database connection is closed. Future versions of SQLite might 2148** make use of additional special filenames that begin with the ":" character. 2149** It is recommended that when a database filename actually does begin with 2150** a ":" character you should prefix the filename with a pathname such as 2151** "./" to avoid ambiguity. 2152** 2153** ^If the filename is an empty string, then a private, temporary 2154** on-disk database will be created. ^This private database will be 2155** automatically deleted as soon as the database connection is closed. 2156** 2157** ^The fourth parameter to sqlite3_open_v2() is the name of the 2158** [sqlite3_vfs] object that defines the operating system interface that 2159** the new database connection should use. ^If the fourth parameter is 2160** a NULL pointer then the default [sqlite3_vfs] object is used. 2161** 2162** <b>Note to Windows users:</b> The encoding used for the filename argument 2163** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever 2164** codepage is currently defined. Filenames containing international 2165** characters must be converted to UTF-8 prior to passing them into 2166** sqlite3_open() or sqlite3_open_v2(). 2167*/ 2168int sqlite3_open( 2169 const char *filename, /* Database filename (UTF-8) */ 2170 sqlite3 **ppDb /* OUT: SQLite db handle */ 2171); 2172int sqlite3_open16( 2173 const void *filename, /* Database filename (UTF-16) */ 2174 sqlite3 **ppDb /* OUT: SQLite db handle */ 2175); 2176int sqlite3_open_v2( 2177 const char *filename, /* Database filename (UTF-8) */ 2178 sqlite3 **ppDb, /* OUT: SQLite db handle */ 2179 int flags, /* Flags */ 2180 const char *zVfs /* Name of VFS module to use */ 2181); 2182 2183/* 2184** CAPI3REF: Error Codes And Messages 2185** 2186** ^The sqlite3_errcode() interface returns the numeric [result code] or 2187** [extended result code] for the most recent failed sqlite3_* API call 2188** associated with a [database connection]. If a prior API call failed 2189** but the most recent API call succeeded, the return value from 2190** sqlite3_errcode() is undefined. ^The sqlite3_extended_errcode() 2191** interface is the same except that it always returns the 2192** [extended result code] even when extended result codes are 2193** disabled. 2194** 2195** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language 2196** text that describes the error, as either UTF-8 or UTF-16 respectively. 2197** ^(Memory to hold the error message string is managed internally. 2198** The application does not need to worry about freeing the result. 2199** However, the error string might be overwritten or deallocated by 2200** subsequent calls to other SQLite interface functions.)^ 2201** 2202** When the serialized [threading mode] is in use, it might be the 2203** case that a second error occurs on a separate thread in between 2204** the time of the first error and the call to these interfaces. 2205** When that happens, the second error will be reported since these 2206** interfaces always report the most recent result. To avoid 2207** this, each thread can obtain exclusive use of the [database connection] D 2208** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning 2209** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after 2210** all calls to the interfaces listed here are completed. 2211** 2212** If an interface fails with SQLITE_MISUSE, that means the interface 2213** was invoked incorrectly by the application. In that case, the 2214** error code and message may or may not be set. 2215*/ 2216int sqlite3_errcode(sqlite3 *db); 2217int sqlite3_extended_errcode(sqlite3 *db); 2218const char *sqlite3_errmsg(sqlite3*); 2219const void *sqlite3_errmsg16(sqlite3*); 2220 2221/* 2222** CAPI3REF: SQL Statement Object 2223** KEYWORDS: {prepared statement} {prepared statements} 2224** 2225** An instance of this object represents a single SQL statement. 2226** This object is variously known as a "prepared statement" or a 2227** "compiled SQL statement" or simply as a "statement". 2228** 2229** The life of a statement object goes something like this: 2230** 2231** <ol> 2232** <li> Create the object using [sqlite3_prepare_v2()] or a related 2233** function. 2234** <li> Bind values to [host parameters] using the sqlite3_bind_*() 2235** interfaces. 2236** <li> Run the SQL by calling [sqlite3_step()] one or more times. 2237** <li> Reset the statement using [sqlite3_reset()] then go back 2238** to step 2. Do this zero or more times. 2239** <li> Destroy the object using [sqlite3_finalize()]. 2240** </ol> 2241** 2242** Refer to documentation on individual methods above for additional 2243** information. 2244*/ 2245typedef struct sqlite3_stmt sqlite3_stmt; 2246 2247/* 2248** CAPI3REF: Run-time Limits 2249** 2250** ^(This interface allows the size of various constructs to be limited 2251** on a connection by connection basis. The first parameter is the 2252** [database connection] whose limit is to be set or queried. The 2253** second parameter is one of the [limit categories] that define a 2254** class of constructs to be size limited. The third parameter is the 2255** new limit for that construct. The function returns the old limit.)^ 2256** 2257** ^If the new limit is a negative number, the limit is unchanged. 2258** ^(For the limit category of SQLITE_LIMIT_XYZ there is a 2259** [limits | hard upper bound] 2260** set by a compile-time C preprocessor macro named 2261** [limits | SQLITE_MAX_XYZ]. 2262** (The "_LIMIT_" in the name is changed to "_MAX_".))^ 2263** ^Attempts to increase a limit above its hard upper bound are 2264** silently truncated to the hard upper bound. 2265** 2266** Run-time limits are intended for use in applications that manage 2267** both their own internal database and also databases that are controlled 2268** by untrusted external sources. An example application might be a 2269** web browser that has its own databases for storing history and 2270** separate databases controlled by JavaScript applications downloaded 2271** off the Internet. The internal databases can be given the 2272** large, default limits. Databases managed by external sources can 2273** be given much smaller limits designed to prevent a denial of service 2274** attack. Developers might also want to use the [sqlite3_set_authorizer()] 2275** interface to further control untrusted SQL. The size of the database 2276** created by an untrusted script can be contained using the 2277** [max_page_count] [PRAGMA]. 2278** 2279** New run-time limit categories may be added in future releases. 2280*/ 2281int sqlite3_limit(sqlite3*, int id, int newVal); 2282 2283/* 2284** CAPI3REF: Run-Time Limit Categories 2285** KEYWORDS: {limit category} {*limit categories} 2286** 2287** These constants define various performance limits 2288** that can be lowered at run-time using [sqlite3_limit()]. 2289** The synopsis of the meanings of the various limits is shown below. 2290** Additional information is available at [limits | Limits in SQLite]. 2291** 2292** <dl> 2293** ^(<dt>SQLITE_LIMIT_LENGTH</dt> 2294** <dd>The maximum size of any string or BLOB or table row.<dd>)^ 2295** 2296** ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt> 2297** <dd>The maximum length of an SQL statement, in bytes.</dd>)^ 2298** 2299** ^(<dt>SQLITE_LIMIT_COLUMN</dt> 2300** <dd>The maximum number of columns in a table definition or in the 2301** result set of a [SELECT] or the maximum number of columns in an index 2302** or in an ORDER BY or GROUP BY clause.</dd>)^ 2303** 2304** ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt> 2305** <dd>The maximum depth of the parse tree on any expression.</dd>)^ 2306** 2307** ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt> 2308** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^ 2309** 2310** ^(<dt>SQLITE_LIMIT_VDBE_OP</dt> 2311** <dd>The maximum number of instructions in a virtual machine program 2312** used to implement an SQL statement.</dd>)^ 2313** 2314** ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt> 2315** <dd>The maximum number of arguments on a function.</dd>)^ 2316** 2317** ^(<dt>SQLITE_LIMIT_ATTACHED</dt> 2318** <dd>The maximum number of [ATTACH | attached databases].)^</dd> 2319** 2320** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt> 2321** <dd>The maximum length of the pattern argument to the [LIKE] or 2322** [GLOB] operators.</dd>)^ 2323** 2324** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt> 2325** <dd>The maximum number of variables in an SQL statement that can 2326** be bound.</dd>)^ 2327** 2328** ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt> 2329** <dd>The maximum depth of recursion for triggers.</dd>)^ 2330** </dl> 2331*/ 2332#define SQLITE_LIMIT_LENGTH 0 2333#define SQLITE_LIMIT_SQL_LENGTH 1 2334#define SQLITE_LIMIT_COLUMN 2 2335#define SQLITE_LIMIT_EXPR_DEPTH 3 2336#define SQLITE_LIMIT_COMPOUND_SELECT 4 2337#define SQLITE_LIMIT_VDBE_OP 5 2338#define SQLITE_LIMIT_FUNCTION_ARG 6 2339#define SQLITE_LIMIT_ATTACHED 7 2340#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 2341#define SQLITE_LIMIT_VARIABLE_NUMBER 9 2342#define SQLITE_LIMIT_TRIGGER_DEPTH 10 2343 2344/* 2345** CAPI3REF: Compiling An SQL Statement 2346** KEYWORDS: {SQL statement compiler} 2347** 2348** To execute an SQL query, it must first be compiled into a byte-code 2349** program using one of these routines. 2350** 2351** The first argument, "db", is a [database connection] obtained from a 2352** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or 2353** [sqlite3_open16()]. The database connection must not have been closed. 2354** 2355** The second argument, "zSql", is the statement to be compiled, encoded 2356** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() 2357** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() 2358** use UTF-16. 2359** 2360** ^If the nByte argument is less than zero, then zSql is read up to the 2361** first zero terminator. ^If nByte is non-negative, then it is the maximum 2362** number of bytes read from zSql. ^When nByte is non-negative, the 2363** zSql string ends at either the first '\000' or '\u0000' character or 2364** the nByte-th byte, whichever comes first. If the caller knows 2365** that the supplied string is nul-terminated, then there is a small 2366** performance advantage to be gained by passing an nByte parameter that 2367** is equal to the number of bytes in the input string <i>including</i> 2368** the nul-terminator bytes. 2369** 2370** ^If pzTail is not NULL then *pzTail is made to point to the first byte 2371** past the end of the first SQL statement in zSql. These routines only 2372** compile the first statement in zSql, so *pzTail is left pointing to 2373** what remains uncompiled. 2374** 2375** ^*ppStmt is left pointing to a compiled [prepared statement] that can be 2376** executed using [sqlite3_step()]. ^If there is an error, *ppStmt is set 2377** to NULL. ^If the input text contains no SQL (if the input is an empty 2378** string or a comment) then *ppStmt is set to NULL. 2379** The calling procedure is responsible for deleting the compiled 2380** SQL statement using [sqlite3_finalize()] after it has finished with it. 2381** ppStmt may not be NULL. 2382** 2383** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK]; 2384** otherwise an [error code] is returned. 2385** 2386** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are 2387** recommended for all new programs. The two older interfaces are retained 2388** for backwards compatibility, but their use is discouraged. 2389** ^In the "v2" interfaces, the prepared statement 2390** that is returned (the [sqlite3_stmt] object) contains a copy of the 2391** original SQL text. This causes the [sqlite3_step()] interface to 2392** behave differently in three ways: 2393** 2394** <ol> 2395** <li> 2396** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it 2397** always used to do, [sqlite3_step()] will automatically recompile the SQL 2398** statement and try to run it again. ^If the schema has changed in 2399** a way that makes the statement no longer valid, [sqlite3_step()] will still 2400** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is 2401** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the 2402** error go away. Note: use [sqlite3_errmsg()] to find the text 2403** of the parsing error that results in an [SQLITE_SCHEMA] return. 2404** </li> 2405** 2406** <li> 2407** ^When an error occurs, [sqlite3_step()] will return one of the detailed 2408** [error codes] or [extended error codes]. ^The legacy behavior was that 2409** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code 2410** and the application would have to make a second call to [sqlite3_reset()] 2411** in order to find the underlying cause of the problem. With the "v2" prepare 2412** interfaces, the underlying reason for the error is returned immediately. 2413** </li> 2414** 2415** <li> 2416** ^If the value of a [parameter | host parameter] in the WHERE clause might 2417** change the query plan for a statement, then the statement may be 2418** automatically recompiled (as if there had been a schema change) on the first 2419** [sqlite3_step()] call following any change to the 2420** [sqlite3_bind_text | bindings] of the [parameter]. 2421** </li> 2422** </ol> 2423*/ 2424int sqlite3_prepare( 2425 sqlite3 *db, /* Database handle */ 2426 const char *zSql, /* SQL statement, UTF-8 encoded */ 2427 int nByte, /* Maximum length of zSql in bytes. */ 2428 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2429 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2430); 2431int sqlite3_prepare_v2( 2432 sqlite3 *db, /* Database handle */ 2433 const char *zSql, /* SQL statement, UTF-8 encoded */ 2434 int nByte, /* Maximum length of zSql in bytes. */ 2435 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2436 const char **pzTail /* OUT: Pointer to unused portion of zSql */ 2437); 2438int sqlite3_prepare16( 2439 sqlite3 *db, /* Database handle */ 2440 const void *zSql, /* SQL statement, UTF-16 encoded */ 2441 int nByte, /* Maximum length of zSql in bytes. */ 2442 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2443 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2444); 2445int sqlite3_prepare16_v2( 2446 sqlite3 *db, /* Database handle */ 2447 const void *zSql, /* SQL statement, UTF-16 encoded */ 2448 int nByte, /* Maximum length of zSql in bytes. */ 2449 sqlite3_stmt **ppStmt, /* OUT: Statement handle */ 2450 const void **pzTail /* OUT: Pointer to unused portion of zSql */ 2451); 2452 2453/* 2454** CAPI3REF: Retrieving Statement SQL 2455** 2456** ^This interface can be used to retrieve a saved copy of the original 2457** SQL text used to create a [prepared statement] if that statement was 2458** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. 2459*/ 2460const char *sqlite3_sql(sqlite3_stmt *pStmt); 2461 2462/* 2463** CAPI3REF: Dynamically Typed Value Object 2464** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} 2465** 2466** SQLite uses the sqlite3_value object to represent all values 2467** that can be stored in a database table. SQLite uses dynamic typing 2468** for the values it stores. ^Values stored in sqlite3_value objects 2469** can be integers, floating point values, strings, BLOBs, or NULL. 2470** 2471** An sqlite3_value object may be either "protected" or "unprotected". 2472** Some interfaces require a protected sqlite3_value. Other interfaces 2473** will accept either a protected or an unprotected sqlite3_value. 2474** Every interface that accepts sqlite3_value arguments specifies 2475** whether or not it requires a protected sqlite3_value. 2476** 2477** The terms "protected" and "unprotected" refer to whether or not 2478** a mutex is held. A internal mutex is held for a protected 2479** sqlite3_value object but no mutex is held for an unprotected 2480** sqlite3_value object. If SQLite is compiled to be single-threaded 2481** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) 2482** or if SQLite is run in one of reduced mutex modes 2483** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] 2484** then there is no distinction between protected and unprotected 2485** sqlite3_value objects and they can be used interchangeably. However, 2486** for maximum code portability it is recommended that applications 2487** still make the distinction between between protected and unprotected 2488** sqlite3_value objects even when not strictly required. 2489** 2490** ^The sqlite3_value objects that are passed as parameters into the 2491** implementation of [application-defined SQL functions] are protected. 2492** ^The sqlite3_value object returned by 2493** [sqlite3_column_value()] is unprotected. 2494** Unprotected sqlite3_value objects may only be used with 2495** [sqlite3_result_value()] and [sqlite3_bind_value()]. 2496** The [sqlite3_value_blob | sqlite3_value_type()] family of 2497** interfaces require protected sqlite3_value objects. 2498*/ 2499typedef struct Mem sqlite3_value; 2500 2501/* 2502** CAPI3REF: SQL Function Context Object 2503** 2504** The context in which an SQL function executes is stored in an 2505** sqlite3_context object. ^A pointer to an sqlite3_context object 2506** is always first parameter to [application-defined SQL functions]. 2507** The application-defined SQL function implementation will pass this 2508** pointer through into calls to [sqlite3_result_int | sqlite3_result()], 2509** [sqlite3_aggregate_context()], [sqlite3_user_data()], 2510** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], 2511** and/or [sqlite3_set_auxdata()]. 2512*/ 2513typedef struct sqlite3_context sqlite3_context; 2514 2515/* 2516** CAPI3REF: Binding Values To Prepared Statements 2517** KEYWORDS: {host parameter} {host parameters} {host parameter name} 2518** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} 2519** 2520** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants, 2521** literals may be replaced by a [parameter] that matches one of following 2522** templates: 2523** 2524** <ul> 2525** <li> ? 2526** <li> ?NNN 2527** <li> :VVV 2528** <li> @VVV 2529** <li> $VVV 2530** </ul> 2531** 2532** In the templates above, NNN represents an integer literal, 2533** and VVV represents an alphanumeric identifer.)^ ^The values of these 2534** parameters (also called "host parameter names" or "SQL parameters") 2535** can be set using the sqlite3_bind_*() routines defined here. 2536** 2537** ^The first argument to the sqlite3_bind_*() routines is always 2538** a pointer to the [sqlite3_stmt] object returned from 2539** [sqlite3_prepare_v2()] or its variants. 2540** 2541** ^The second argument is the index of the SQL parameter to be set. 2542** ^The leftmost SQL parameter has an index of 1. ^When the same named 2543** SQL parameter is used more than once, second and subsequent 2544** occurrences have the same index as the first occurrence. 2545** ^The index for named parameters can be looked up using the 2546** [sqlite3_bind_parameter_index()] API if desired. ^The index 2547** for "?NNN" parameters is the value of NNN. 2548** ^The NNN value must be between 1 and the [sqlite3_limit()] 2549** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). 2550** 2551** ^The third argument is the value to bind to the parameter. 2552** 2553** ^(In those routines that have a fourth argument, its value is the 2554** number of bytes in the parameter. To be clear: the value is the 2555** number of <u>bytes</u> in the value, not the number of characters.)^ 2556** ^If the fourth parameter is negative, the length of the string is 2557** the number of bytes up to the first zero terminator. 2558** 2559** ^The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and 2560** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or 2561** string after SQLite has finished with it. ^If the fifth argument is 2562** the special value [SQLITE_STATIC], then SQLite assumes that the 2563** information is in static, unmanaged space and does not need to be freed. 2564** ^If the fifth argument has the value [SQLITE_TRANSIENT], then 2565** SQLite makes its own private copy of the data immediately, before 2566** the sqlite3_bind_*() routine returns. 2567** 2568** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that 2569** is filled with zeroes. ^A zeroblob uses a fixed amount of memory 2570** (just an integer to hold its size) while it is being processed. 2571** Zeroblobs are intended to serve as placeholders for BLOBs whose 2572** content is later written using 2573** [sqlite3_blob_open | incremental BLOB I/O] routines. 2574** ^A negative value for the zeroblob results in a zero-length BLOB. 2575** 2576** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer 2577** for the [prepared statement] or with a prepared statement for which 2578** [sqlite3_step()] has been called more recently than [sqlite3_reset()], 2579** then the call will return [SQLITE_MISUSE]. If any sqlite3_bind_() 2580** routine is passed a [prepared statement] that has been finalized, the 2581** result is undefined and probably harmful. 2582** 2583** ^Bindings are not cleared by the [sqlite3_reset()] routine. 2584** ^Unbound parameters are interpreted as NULL. 2585** 2586** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an 2587** [error code] if anything goes wrong. 2588** ^[SQLITE_RANGE] is returned if the parameter 2589** index is out of range. ^[SQLITE_NOMEM] is returned if malloc() fails. 2590** 2591** See also: [sqlite3_bind_parameter_count()], 2592** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. 2593*/ 2594int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); 2595int sqlite3_bind_double(sqlite3_stmt*, int, double); 2596int sqlite3_bind_int(sqlite3_stmt*, int, int); 2597int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); 2598int sqlite3_bind_null(sqlite3_stmt*, int); 2599int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); 2600int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); 2601int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); 2602int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); 2603 2604/* 2605** CAPI3REF: Number Of SQL Parameters 2606** 2607** ^This routine can be used to find the number of [SQL parameters] 2608** in a [prepared statement]. SQL parameters are tokens of the 2609** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as 2610** placeholders for values that are [sqlite3_bind_blob | bound] 2611** to the parameters at a later time. 2612** 2613** ^(This routine actually returns the index of the largest (rightmost) 2614** parameter. For all forms except ?NNN, this will correspond to the 2615** number of unique parameters. If parameters of the ?NNN form are used, 2616** there may be gaps in the list.)^ 2617** 2618** See also: [sqlite3_bind_blob|sqlite3_bind()], 2619** [sqlite3_bind_parameter_name()], and 2620** [sqlite3_bind_parameter_index()]. 2621*/ 2622int sqlite3_bind_parameter_count(sqlite3_stmt*); 2623 2624/* 2625** CAPI3REF: Name Of A Host Parameter 2626** 2627** ^The sqlite3_bind_parameter_name(P,N) interface returns 2628** the name of the N-th [SQL parameter] in the [prepared statement] P. 2629** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" 2630** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" 2631** respectively. 2632** In other words, the initial ":" or "$" or "@" or "?" 2633** is included as part of the name.)^ 2634** ^Parameters of the form "?" without a following integer have no name 2635** and are referred to as "nameless" or "anonymous parameters". 2636** 2637** ^The first host parameter has an index of 1, not 0. 2638** 2639** ^If the value N is out of range or if the N-th parameter is 2640** nameless, then NULL is returned. ^The returned string is 2641** always in UTF-8 encoding even if the named parameter was 2642** originally specified as UTF-16 in [sqlite3_prepare16()] or 2643** [sqlite3_prepare16_v2()]. 2644** 2645** See also: [sqlite3_bind_blob|sqlite3_bind()], 2646** [sqlite3_bind_parameter_count()], and 2647** [sqlite3_bind_parameter_index()]. 2648*/ 2649const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); 2650 2651/* 2652** CAPI3REF: Index Of A Parameter With A Given Name 2653** 2654** ^Return the index of an SQL parameter given its name. ^The 2655** index value returned is suitable for use as the second 2656** parameter to [sqlite3_bind_blob|sqlite3_bind()]. ^A zero 2657** is returned if no matching parameter is found. ^The parameter 2658** name must be given in UTF-8 even if the original statement 2659** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. 2660** 2661** See also: [sqlite3_bind_blob|sqlite3_bind()], 2662** [sqlite3_bind_parameter_count()], and 2663** [sqlite3_bind_parameter_index()]. 2664*/ 2665int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); 2666 2667/* 2668** CAPI3REF: Reset All Bindings On A Prepared Statement 2669** 2670** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset 2671** the [sqlite3_bind_blob | bindings] on a [prepared statement]. 2672** ^Use this routine to reset all host parameters to NULL. 2673*/ 2674int sqlite3_clear_bindings(sqlite3_stmt*); 2675 2676/* 2677** CAPI3REF: Number Of Columns In A Result Set 2678** 2679** ^Return the number of columns in the result set returned by the 2680** [prepared statement]. ^This routine returns 0 if pStmt is an SQL 2681** statement that does not return data (for example an [UPDATE]). 2682*/ 2683int sqlite3_column_count(sqlite3_stmt *pStmt); 2684 2685/* 2686** CAPI3REF: Column Names In A Result Set 2687** 2688** ^These routines return the name assigned to a particular column 2689** in the result set of a [SELECT] statement. ^The sqlite3_column_name() 2690** interface returns a pointer to a zero-terminated UTF-8 string 2691** and sqlite3_column_name16() returns a pointer to a zero-terminated 2692** UTF-16 string. ^The first parameter is the [prepared statement] 2693** that implements the [SELECT] statement. ^The second parameter is the 2694** column number. ^The leftmost column is number 0. 2695** 2696** ^The returned string pointer is valid until either the [prepared statement] 2697** is destroyed by [sqlite3_finalize()] or until the next call to 2698** sqlite3_column_name() or sqlite3_column_name16() on the same column. 2699** 2700** ^If sqlite3_malloc() fails during the processing of either routine 2701** (for example during a conversion from UTF-8 to UTF-16) then a 2702** NULL pointer is returned. 2703** 2704** ^The name of a result column is the value of the "AS" clause for 2705** that column, if there is an AS clause. If there is no AS clause 2706** then the name of the column is unspecified and may change from 2707** one release of SQLite to the next. 2708*/ 2709const char *sqlite3_column_name(sqlite3_stmt*, int N); 2710const void *sqlite3_column_name16(sqlite3_stmt*, int N); 2711 2712/* 2713** CAPI3REF: Source Of Data In A Query Result 2714** 2715** ^These routines provide a means to determine the database, table, and 2716** table column that is the origin of a particular result column in 2717** [SELECT] statement. 2718** ^The name of the database or table or column can be returned as 2719** either a UTF-8 or UTF-16 string. ^The _database_ routines return 2720** the database name, the _table_ routines return the table name, and 2721** the origin_ routines return the column name. 2722** ^The returned string is valid until the [prepared statement] is destroyed 2723** using [sqlite3_finalize()] or until the same information is requested 2724** again in a different encoding. 2725** 2726** ^The names returned are the original un-aliased names of the 2727** database, table, and column. 2728** 2729** ^The first argument to these interfaces is a [prepared statement]. 2730** ^These functions return information about the Nth result column returned by 2731** the statement, where N is the second function argument. 2732** ^The left-most column is column 0 for these routines. 2733** 2734** ^If the Nth column returned by the statement is an expression or 2735** subquery and is not a column value, then all of these functions return 2736** NULL. ^These routine might also return NULL if a memory allocation error 2737** occurs. ^Otherwise, they return the name of the attached database, table, 2738** or column that query result column was extracted from. 2739** 2740** ^As with all other SQLite APIs, those whose names end with "16" return 2741** UTF-16 encoded strings and the other functions return UTF-8. 2742** 2743** ^These APIs are only available if the library was compiled with the 2744** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol. 2745** 2746** If two or more threads call one or more of these routines against the same 2747** prepared statement and column at the same time then the results are 2748** undefined. 2749** 2750** If two or more threads call one or more 2751** [sqlite3_column_database_name | column metadata interfaces] 2752** for the same [prepared statement] and result column 2753** at the same time then the results are undefined. 2754*/ 2755const char *sqlite3_column_database_name(sqlite3_stmt*,int); 2756const void *sqlite3_column_database_name16(sqlite3_stmt*,int); 2757const char *sqlite3_column_table_name(sqlite3_stmt*,int); 2758const void *sqlite3_column_table_name16(sqlite3_stmt*,int); 2759const char *sqlite3_column_origin_name(sqlite3_stmt*,int); 2760const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); 2761 2762/* 2763** CAPI3REF: Declared Datatype Of A Query Result 2764** 2765** ^(The first parameter is a [prepared statement]. 2766** If this statement is a [SELECT] statement and the Nth column of the 2767** returned result set of that [SELECT] is a table column (not an 2768** expression or subquery) then the declared type of the table 2769** column is returned.)^ ^If the Nth column of the result set is an 2770** expression or subquery, then a NULL pointer is returned. 2771** ^The returned string is always UTF-8 encoded. 2772** 2773** ^(For example, given the database schema: 2774** 2775** CREATE TABLE t1(c1 VARIANT); 2776** 2777** and the following statement to be compiled: 2778** 2779** SELECT c1 + 1, c1 FROM t1; 2780** 2781** this routine would return the string "VARIANT" for the second result 2782** column (i==1), and a NULL pointer for the first result column (i==0).)^ 2783** 2784** ^SQLite uses dynamic run-time typing. ^So just because a column 2785** is declared to contain a particular type does not mean that the 2786** data stored in that column is of the declared type. SQLite is 2787** strongly typed, but the typing is dynamic not static. ^Type 2788** is associated with individual values, not with the containers 2789** used to hold those values. 2790*/ 2791const char *sqlite3_column_decltype(sqlite3_stmt*,int); 2792const void *sqlite3_column_decltype16(sqlite3_stmt*,int); 2793 2794/* 2795** CAPI3REF: Evaluate An SQL Statement 2796** 2797** After a [prepared statement] has been prepared using either 2798** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy 2799** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function 2800** must be called one or more times to evaluate the statement. 2801** 2802** The details of the behavior of the sqlite3_step() interface depend 2803** on whether the statement was prepared using the newer "v2" interface 2804** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy 2805** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the 2806** new "v2" interface is recommended for new applications but the legacy 2807** interface will continue to be supported. 2808** 2809** ^In the legacy interface, the return value will be either [SQLITE_BUSY], 2810** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. 2811** ^With the "v2" interface, any of the other [result codes] or 2812** [extended result codes] might be returned as well. 2813** 2814** ^[SQLITE_BUSY] means that the database engine was unable to acquire the 2815** database locks it needs to do its job. ^If the statement is a [COMMIT] 2816** or occurs outside of an explicit transaction, then you can retry the 2817** statement. If the statement is not a [COMMIT] and occurs within a 2818** explicit transaction then you should rollback the transaction before 2819** continuing. 2820** 2821** ^[SQLITE_DONE] means that the statement has finished executing 2822** successfully. sqlite3_step() should not be called again on this virtual 2823** machine without first calling [sqlite3_reset()] to reset the virtual 2824** machine back to its initial state. 2825** 2826** ^If the SQL statement being executed returns any data, then [SQLITE_ROW] 2827** is returned each time a new row of data is ready for processing by the 2828** caller. The values may be accessed using the [column access functions]. 2829** sqlite3_step() is called again to retrieve the next row of data. 2830** 2831** ^[SQLITE_ERROR] means that a run-time error (such as a constraint 2832** violation) has occurred. sqlite3_step() should not be called again on 2833** the VM. More information may be found by calling [sqlite3_errmsg()]. 2834** ^With the legacy interface, a more specific error code (for example, 2835** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) 2836** can be obtained by calling [sqlite3_reset()] on the 2837** [prepared statement]. ^In the "v2" interface, 2838** the more specific error code is returned directly by sqlite3_step(). 2839** 2840** [SQLITE_MISUSE] means that the this routine was called inappropriately. 2841** Perhaps it was called on a [prepared statement] that has 2842** already been [sqlite3_finalize | finalized] or on one that had 2843** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could 2844** be the case that the same database connection is being used by two or 2845** more threads at the same moment in time. 2846** 2847** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step() 2848** API always returns a generic error code, [SQLITE_ERROR], following any 2849** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call 2850** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the 2851** specific [error codes] that better describes the error. 2852** We admit that this is a goofy design. The problem has been fixed 2853** with the "v2" interface. If you prepare all of your SQL statements 2854** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead 2855** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, 2856** then the more specific [error codes] are returned directly 2857** by sqlite3_step(). The use of the "v2" interface is recommended. 2858*/ 2859int sqlite3_step(sqlite3_stmt*); 2860 2861/* 2862** CAPI3REF: Number of columns in a result set 2863** 2864** ^The sqlite3_data_count(P) the number of columns in the 2865** of the result set of [prepared statement] P. 2866*/ 2867int sqlite3_data_count(sqlite3_stmt *pStmt); 2868 2869/* 2870** CAPI3REF: Fundamental Datatypes 2871** KEYWORDS: SQLITE_TEXT 2872** 2873** ^(Every value in SQLite has one of five fundamental datatypes: 2874** 2875** <ul> 2876** <li> 64-bit signed integer 2877** <li> 64-bit IEEE floating point number 2878** <li> string 2879** <li> BLOB 2880** <li> NULL 2881** </ul>)^ 2882** 2883** These constants are codes for each of those types. 2884** 2885** Note that the SQLITE_TEXT constant was also used in SQLite version 2 2886** for a completely different meaning. Software that links against both 2887** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not 2888** SQLITE_TEXT. 2889*/ 2890#define SQLITE_INTEGER 1 2891#define SQLITE_FLOAT 2 2892#define SQLITE_BLOB 4 2893#define SQLITE_NULL 5 2894#ifdef SQLITE_TEXT 2895# undef SQLITE_TEXT 2896#else 2897# define SQLITE_TEXT 3 2898#endif 2899#define SQLITE3_TEXT 3 2900 2901/* 2902** CAPI3REF: Result Values From A Query 2903** KEYWORDS: {column access functions} 2904** 2905** These routines form the "result set" interface. 2906** 2907** ^These routines return information about a single column of the current 2908** result row of a query. ^In every case the first argument is a pointer 2909** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] 2910** that was returned from [sqlite3_prepare_v2()] or one of its variants) 2911** and the second argument is the index of the column for which information 2912** should be returned. ^The leftmost column of the result set has the index 0. 2913** ^The number of columns in the result can be determined using 2914** [sqlite3_column_count()]. 2915** 2916** If the SQL statement does not currently point to a valid row, or if the 2917** column index is out of range, the result is undefined. 2918** These routines may only be called when the most recent call to 2919** [sqlite3_step()] has returned [SQLITE_ROW] and neither 2920** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. 2921** If any of these routines are called after [sqlite3_reset()] or 2922** [sqlite3_finalize()] or after [sqlite3_step()] has returned 2923** something other than [SQLITE_ROW], the results are undefined. 2924** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] 2925** are called from a different thread while any of these routines 2926** are pending, then the results are undefined. 2927** 2928** ^The sqlite3_column_type() routine returns the 2929** [SQLITE_INTEGER | datatype code] for the initial data type 2930** of the result column. ^The returned value is one of [SQLITE_INTEGER], 2931** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value 2932** returned by sqlite3_column_type() is only meaningful if no type 2933** conversions have occurred as described below. After a type conversion, 2934** the value returned by sqlite3_column_type() is undefined. Future 2935** versions of SQLite may change the behavior of sqlite3_column_type() 2936** following a type conversion. 2937** 2938** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() 2939** routine returns the number of bytes in that BLOB or string. 2940** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts 2941** the string to UTF-8 and then returns the number of bytes. 2942** ^If the result is a numeric value then sqlite3_column_bytes() uses 2943** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns 2944** the number of bytes in that string. 2945** ^The value returned does not include the zero terminator at the end 2946** of the string. ^For clarity: the value returned is the number of 2947** bytes in the string, not the number of characters. 2948** 2949** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(), 2950** even empty strings, are always zero terminated. ^The return 2951** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary 2952** pointer, possibly even a NULL pointer. 2953** 2954** ^The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() 2955** but leaves the result in UTF-16 in native byte order instead of UTF-8. 2956** ^The zero terminator is not included in this count. 2957** 2958** ^The object returned by [sqlite3_column_value()] is an 2959** [unprotected sqlite3_value] object. An unprotected sqlite3_value object 2960** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. 2961** If the [unprotected sqlite3_value] object returned by 2962** [sqlite3_column_value()] is used in any other way, including calls 2963** to routines like [sqlite3_value_int()], [sqlite3_value_text()], 2964** or [sqlite3_value_bytes()], then the behavior is undefined. 2965** 2966** These routines attempt to convert the value where appropriate. ^For 2967** example, if the internal representation is FLOAT and a text result 2968** is requested, [sqlite3_snprintf()] is used internally to perform the 2969** conversion automatically. ^(The following table details the conversions 2970** that are applied: 2971** 2972** <blockquote> 2973** <table border="1"> 2974** <tr><th> Internal<br>Type <th> Requested<br>Type <th> Conversion 2975** 2976** <tr><td> NULL <td> INTEGER <td> Result is 0 2977** <tr><td> NULL <td> FLOAT <td> Result is 0.0 2978** <tr><td> NULL <td> TEXT <td> Result is NULL pointer 2979** <tr><td> NULL <td> BLOB <td> Result is NULL pointer 2980** <tr><td> INTEGER <td> FLOAT <td> Convert from integer to float 2981** <tr><td> INTEGER <td> TEXT <td> ASCII rendering of the integer 2982** <tr><td> INTEGER <td> BLOB <td> Same as INTEGER->TEXT 2983** <tr><td> FLOAT <td> INTEGER <td> Convert from float to integer 2984** <tr><td> FLOAT <td> TEXT <td> ASCII rendering of the float 2985** <tr><td> FLOAT <td> BLOB <td> Same as FLOAT->TEXT 2986** <tr><td> TEXT <td> INTEGER <td> Use atoi() 2987** <tr><td> TEXT <td> FLOAT <td> Use atof() 2988** <tr><td> TEXT <td> BLOB <td> No change 2989** <tr><td> BLOB <td> INTEGER <td> Convert to TEXT then use atoi() 2990** <tr><td> BLOB <td> FLOAT <td> Convert to TEXT then use atof() 2991** <tr><td> BLOB <td> TEXT <td> Add a zero terminator if needed 2992** </table> 2993** </blockquote>)^ 2994** 2995** The table above makes reference to standard C library functions atoi() 2996** and atof(). SQLite does not really use these functions. It has its 2997** own equivalent internal routines. The atoi() and atof() names are 2998** used in the table for brevity and because they are familiar to most 2999** C programmers. 3000** 3001** ^Note that when type conversions occur, pointers returned by prior 3002** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or 3003** sqlite3_column_text16() may be invalidated. 3004** ^(Type conversions and pointer invalidations might occur 3005** in the following cases: 3006** 3007** <ul> 3008** <li> The initial content is a BLOB and sqlite3_column_text() or 3009** sqlite3_column_text16() is called. A zero-terminator might 3010** need to be added to the string.</li> 3011** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or 3012** sqlite3_column_text16() is called. The content must be converted 3013** to UTF-16.</li> 3014** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or 3015** sqlite3_column_text() is called. The content must be converted 3016** to UTF-8.</li> 3017** </ul>)^ 3018** 3019** ^Conversions between UTF-16be and UTF-16le are always done in place and do 3020** not invalidate a prior pointer, though of course the content of the buffer 3021** that the prior pointer points to will have been modified. Other kinds 3022** of conversion are done in place when it is possible, but sometimes they 3023** are not possible and in those cases prior pointers are invalidated. 3024** 3025** ^(The safest and easiest to remember policy is to invoke these routines 3026** in one of the following ways: 3027** 3028** <ul> 3029** <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li> 3030** <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li> 3031** <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li> 3032** </ul>)^ 3033** 3034** In other words, you should call sqlite3_column_text(), 3035** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result 3036** into the desired format, then invoke sqlite3_column_bytes() or 3037** sqlite3_column_bytes16() to find the size of the result. Do not mix calls 3038** to sqlite3_column_text() or sqlite3_column_blob() with calls to 3039** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() 3040** with calls to sqlite3_column_bytes(). 3041** 3042** ^The pointers returned are valid until a type conversion occurs as 3043** described above, or until [sqlite3_step()] or [sqlite3_reset()] or 3044** [sqlite3_finalize()] is called. ^The memory space used to hold strings 3045** and BLOBs is freed automatically. Do <b>not</b> pass the pointers returned 3046** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into 3047** [sqlite3_free()]. 3048** 3049** ^(If a memory allocation error occurs during the evaluation of any 3050** of these routines, a default value is returned. The default value 3051** is either the integer 0, the floating point number 0.0, or a NULL 3052** pointer. Subsequent calls to [sqlite3_errcode()] will return 3053** [SQLITE_NOMEM].)^ 3054*/ 3055const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); 3056int sqlite3_column_bytes(sqlite3_stmt*, int iCol); 3057int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); 3058double sqlite3_column_double(sqlite3_stmt*, int iCol); 3059int sqlite3_column_int(sqlite3_stmt*, int iCol); 3060sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); 3061const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); 3062const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); 3063int sqlite3_column_type(sqlite3_stmt*, int iCol); 3064sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); 3065 3066/* 3067** CAPI3REF: Destroy A Prepared Statement Object 3068** 3069** ^The sqlite3_finalize() function is called to delete a [prepared statement]. 3070** ^If the statement was executed successfully or not executed at all, then 3071** SQLITE_OK is returned. ^If execution of the statement failed then an 3072** [error code] or [extended error code] is returned. 3073** 3074** ^This routine can be called at any point during the execution of the 3075** [prepared statement]. ^If the virtual machine has not 3076** completed execution when this routine is called, that is like 3077** encountering an error or an [sqlite3_interrupt | interrupt]. 3078** ^Incomplete updates may be rolled back and transactions canceled, 3079** depending on the circumstances, and the 3080** [error code] returned will be [SQLITE_ABORT]. 3081*/ 3082int sqlite3_finalize(sqlite3_stmt *pStmt); 3083 3084/* 3085** CAPI3REF: Reset A Prepared Statement Object 3086** 3087** The sqlite3_reset() function is called to reset a [prepared statement] 3088** object back to its initial state, ready to be re-executed. 3089** ^Any SQL statement variables that had values bound to them using 3090** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. 3091** Use [sqlite3_clear_bindings()] to reset the bindings. 3092** 3093** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S 3094** back to the beginning of its program. 3095** 3096** ^If the most recent call to [sqlite3_step(S)] for the 3097** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], 3098** or if [sqlite3_step(S)] has never before been called on S, 3099** then [sqlite3_reset(S)] returns [SQLITE_OK]. 3100** 3101** ^If the most recent call to [sqlite3_step(S)] for the 3102** [prepared statement] S indicated an error, then 3103** [sqlite3_reset(S)] returns an appropriate [error code]. 3104** 3105** ^The [sqlite3_reset(S)] interface does not change the values 3106** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. 3107*/ 3108int sqlite3_reset(sqlite3_stmt *pStmt); 3109 3110/* 3111** CAPI3REF: Create Or Redefine SQL Functions 3112** KEYWORDS: {function creation routines} 3113** KEYWORDS: {application-defined SQL function} 3114** KEYWORDS: {application-defined SQL functions} 3115** 3116** ^These two functions (collectively known as "function creation routines") 3117** are used to add SQL functions or aggregates or to redefine the behavior 3118** of existing SQL functions or aggregates. The only difference between the 3119** two is that the second parameter, the name of the (scalar) function or 3120** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 3121** for sqlite3_create_function16(). 3122** 3123** ^The first parameter is the [database connection] to which the SQL 3124** function is to be added. ^If an application uses more than one database 3125** connection then application-defined SQL functions must be added 3126** to each database connection separately. 3127** 3128** The second parameter is the name of the SQL function to be created or 3129** redefined. ^The length of the name is limited to 255 bytes, exclusive of 3130** the zero-terminator. Note that the name length limit is in bytes, not 3131** characters. ^Any attempt to create a function with a longer name 3132** will result in [SQLITE_ERROR] being returned. 3133** 3134** ^The third parameter (nArg) 3135** is the number of arguments that the SQL function or 3136** aggregate takes. ^If this parameter is -1, then the SQL function or 3137** aggregate may take any number of arguments between 0 and the limit 3138** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]). If the third 3139** parameter is less than -1 or greater than 127 then the behavior is 3140** undefined. 3141** 3142** The fourth parameter, eTextRep, specifies what 3143** [SQLITE_UTF8 | text encoding] this SQL function prefers for 3144** its parameters. Any SQL function implementation should be able to work 3145** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be 3146** more efficient with one encoding than another. ^An application may 3147** invoke sqlite3_create_function() or sqlite3_create_function16() multiple 3148** times with the same function but with different values of eTextRep. 3149** ^When multiple implementations of the same function are available, SQLite 3150** will pick the one that involves the least amount of data conversion. 3151** If there is only a single implementation which does not care what text 3152** encoding is used, then the fourth argument should be [SQLITE_ANY]. 3153** 3154** ^(The fifth parameter is an arbitrary pointer. The implementation of the 3155** function can gain access to this pointer using [sqlite3_user_data()].)^ 3156** 3157** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are 3158** pointers to C-language functions that implement the SQL function or 3159** aggregate. ^A scalar SQL function requires an implementation of the xFunc 3160** callback only; NULL pointers should be passed as the xStep and xFinal 3161** parameters. ^An aggregate SQL function requires an implementation of xStep 3162** and xFinal and NULL should be passed for xFunc. ^To delete an existing 3163** SQL function or aggregate, pass NULL for all three function callbacks. 3164** 3165** ^It is permitted to register multiple implementations of the same 3166** functions with the same name but with either differing numbers of 3167** arguments or differing preferred text encodings. ^SQLite will use 3168** the implementation that most closely matches the way in which the 3169** SQL function is used. ^A function implementation with a non-negative 3170** nArg parameter is a better match than a function implementation with 3171** a negative nArg. ^A function where the preferred text encoding 3172** matches the database encoding is a better 3173** match than a function where the encoding is different. 3174** ^A function where the encoding difference is between UTF16le and UTF16be 3175** is a closer match than a function where the encoding difference is 3176** between UTF8 and UTF16. 3177** 3178** ^Built-in functions may be overloaded by new application-defined functions. 3179** ^The first application-defined function with a given name overrides all 3180** built-in functions in the same [database connection] with the same name. 3181** ^Subsequent application-defined functions of the same name only override 3182** prior application-defined functions that are an exact match for the 3183** number of parameters and preferred encoding. 3184** 3185** ^An application-defined function is permitted to call other 3186** SQLite interfaces. However, such calls must not 3187** close the database connection nor finalize or reset the prepared 3188** statement in which the function is running. 3189*/ 3190int sqlite3_create_function( 3191 sqlite3 *db, 3192 const char *zFunctionName, 3193 int nArg, 3194 int eTextRep, 3195 void *pApp, 3196 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3197 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3198 void (*xFinal)(sqlite3_context*) 3199); 3200int sqlite3_create_function16( 3201 sqlite3 *db, 3202 const void *zFunctionName, 3203 int nArg, 3204 int eTextRep, 3205 void *pApp, 3206 void (*xFunc)(sqlite3_context*,int,sqlite3_value**), 3207 void (*xStep)(sqlite3_context*,int,sqlite3_value**), 3208 void (*xFinal)(sqlite3_context*) 3209); 3210 3211/* 3212** CAPI3REF: Text Encodings 3213** 3214** These constant define integer codes that represent the various 3215** text encodings supported by SQLite. 3216*/ 3217#define SQLITE_UTF8 1 3218#define SQLITE_UTF16LE 2 3219#define SQLITE_UTF16BE 3 3220#define SQLITE_UTF16 4 /* Use native byte order */ 3221#define SQLITE_ANY 5 /* sqlite3_create_function only */ 3222#define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ 3223 3224/* 3225** CAPI3REF: Deprecated Functions 3226** DEPRECATED 3227** 3228** These functions are [deprecated]. In order to maintain 3229** backwards compatibility with older code, these functions continue 3230** to be supported. However, new applications should avoid 3231** the use of these functions. To help encourage people to avoid 3232** using these functions, we are not going to tell you what they do. 3233*/ 3234#ifndef SQLITE_OMIT_DEPRECATED 3235SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); 3236SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); 3237SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); 3238SQLITE_DEPRECATED int sqlite3_global_recover(void); 3239SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); 3240SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); 3241#endif 3242 3243/* 3244** CAPI3REF: Obtaining SQL Function Parameter Values 3245** 3246** The C-language implementation of SQL functions and aggregates uses 3247** this set of interface routines to access the parameter values on 3248** the function or aggregate. 3249** 3250** The xFunc (for scalar functions) or xStep (for aggregates) parameters 3251** to [sqlite3_create_function()] and [sqlite3_create_function16()] 3252** define callbacks that implement the SQL functions and aggregates. 3253** The 4th parameter to these callbacks is an array of pointers to 3254** [protected sqlite3_value] objects. There is one [sqlite3_value] object for 3255** each parameter to the SQL function. These routines are used to 3256** extract values from the [sqlite3_value] objects. 3257** 3258** These routines work only with [protected sqlite3_value] objects. 3259** Any attempt to use these routines on an [unprotected sqlite3_value] 3260** object results in undefined behavior. 3261** 3262** ^These routines work just like the corresponding [column access functions] 3263** except that these routines take a single [protected sqlite3_value] object 3264** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. 3265** 3266** ^The sqlite3_value_text16() interface extracts a UTF-16 string 3267** in the native byte-order of the host machine. ^The 3268** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces 3269** extract UTF-16 strings as big-endian and little-endian respectively. 3270** 3271** ^(The sqlite3_value_numeric_type() interface attempts to apply 3272** numeric affinity to the value. This means that an attempt is 3273** made to convert the value to an integer or floating point. If 3274** such a conversion is possible without loss of information (in other 3275** words, if the value is a string that looks like a number) 3276** then the conversion is performed. Otherwise no conversion occurs. 3277** The [SQLITE_INTEGER | datatype] after conversion is returned.)^ 3278** 3279** Please pay particular attention to the fact that the pointer returned 3280** from [sqlite3_value_blob()], [sqlite3_value_text()], or 3281** [sqlite3_value_text16()] can be invalidated by a subsequent call to 3282** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], 3283** or [sqlite3_value_text16()]. 3284** 3285** These routines must be called from the same thread as 3286** the SQL function that supplied the [sqlite3_value*] parameters. 3287*/ 3288const void *sqlite3_value_blob(sqlite3_value*); 3289int sqlite3_value_bytes(sqlite3_value*); 3290int sqlite3_value_bytes16(sqlite3_value*); 3291double sqlite3_value_double(sqlite3_value*); 3292int sqlite3_value_int(sqlite3_value*); 3293sqlite3_int64 sqlite3_value_int64(sqlite3_value*); 3294const unsigned char *sqlite3_value_text(sqlite3_value*); 3295const void *sqlite3_value_text16(sqlite3_value*); 3296const void *sqlite3_value_text16le(sqlite3_value*); 3297const void *sqlite3_value_text16be(sqlite3_value*); 3298int sqlite3_value_type(sqlite3_value*); 3299int sqlite3_value_numeric_type(sqlite3_value*); 3300 3301/* 3302** CAPI3REF: Obtain Aggregate Function Context 3303** 3304** Implementions of aggregate SQL functions use this 3305** routine to allocate memory for storing their state. 3306** 3307** ^The first time the sqlite3_aggregate_context(C,N) routine is called 3308** for a particular aggregate function, SQLite 3309** allocates N of memory, zeroes out that memory, and returns a pointer 3310** to the new memory. ^On second and subsequent calls to 3311** sqlite3_aggregate_context() for the same aggregate function instance, 3312** the same buffer is returned. Sqlite3_aggregate_context() is normally 3313** called once for each invocation of the xStep callback and then one 3314** last time when the xFinal callback is invoked. ^(When no rows match 3315** an aggregate query, the xStep() callback of the aggregate function 3316** implementation is never called and xFinal() is called exactly once. 3317** In those cases, sqlite3_aggregate_context() might be called for the 3318** first time from within xFinal().)^ 3319** 3320** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer if N is 3321** less than or equal to zero or if a memory allocate error occurs. 3322** 3323** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is 3324** determined by the N parameter on first successful call. Changing the 3325** value of N in subsequent call to sqlite3_aggregate_context() within 3326** the same aggregate function instance will not resize the memory 3327** allocation.)^ 3328** 3329** ^SQLite automatically frees the memory allocated by 3330** sqlite3_aggregate_context() when the aggregate query concludes. 3331** 3332** The first parameter must be a copy of the 3333** [sqlite3_context | SQL function context] that is the first parameter 3334** to the xStep or xFinal callback routine that implements the aggregate 3335** function. 3336** 3337** This routine must be called from the same thread in which 3338** the aggregate SQL function is running. 3339*/ 3340void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); 3341 3342/* 3343** CAPI3REF: User Data For Functions 3344** 3345** ^The sqlite3_user_data() interface returns a copy of 3346** the pointer that was the pUserData parameter (the 5th parameter) 3347** of the [sqlite3_create_function()] 3348** and [sqlite3_create_function16()] routines that originally 3349** registered the application defined function. 3350** 3351** This routine must be called from the same thread in which 3352** the application-defined function is running. 3353*/ 3354void *sqlite3_user_data(sqlite3_context*); 3355 3356/* 3357** CAPI3REF: Database Connection For Functions 3358** 3359** ^The sqlite3_context_db_handle() interface returns a copy of 3360** the pointer to the [database connection] (the 1st parameter) 3361** of the [sqlite3_create_function()] 3362** and [sqlite3_create_function16()] routines that originally 3363** registered the application defined function. 3364*/ 3365sqlite3 *sqlite3_context_db_handle(sqlite3_context*); 3366 3367/* 3368** CAPI3REF: Function Auxiliary Data 3369** 3370** The following two functions may be used by scalar SQL functions to 3371** associate metadata with argument values. If the same value is passed to 3372** multiple invocations of the same SQL function during query execution, under 3373** some circumstances the associated metadata may be preserved. This may 3374** be used, for example, to add a regular-expression matching scalar 3375** function. The compiled version of the regular expression is stored as 3376** metadata associated with the SQL value passed as the regular expression 3377** pattern. The compiled regular expression can be reused on multiple 3378** invocations of the same function so that the original pattern string 3379** does not need to be recompiled on each invocation. 3380** 3381** ^The sqlite3_get_auxdata() interface returns a pointer to the metadata 3382** associated by the sqlite3_set_auxdata() function with the Nth argument 3383** value to the application-defined function. ^If no metadata has been ever 3384** been set for the Nth argument of the function, or if the corresponding 3385** function parameter has changed since the meta-data was set, 3386** then sqlite3_get_auxdata() returns a NULL pointer. 3387** 3388** ^The sqlite3_set_auxdata() interface saves the metadata 3389** pointed to by its 3rd parameter as the metadata for the N-th 3390** argument of the application-defined function. Subsequent 3391** calls to sqlite3_get_auxdata() might return this data, if it has 3392** not been destroyed. 3393** ^If it is not NULL, SQLite will invoke the destructor 3394** function given by the 4th parameter to sqlite3_set_auxdata() on 3395** the metadata when the corresponding function parameter changes 3396** or when the SQL statement completes, whichever comes first. 3397** 3398** SQLite is free to call the destructor and drop metadata on any 3399** parameter of any function at any time. ^The only guarantee is that 3400** the destructor will be called before the metadata is dropped. 3401** 3402** ^(In practice, metadata is preserved between function calls for 3403** expressions that are constant at compile time. This includes literal 3404** values and [parameters].)^ 3405** 3406** These routines must be called from the same thread in which 3407** the SQL function is running. 3408*/ 3409void *sqlite3_get_auxdata(sqlite3_context*, int N); 3410void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); 3411 3412 3413/* 3414** CAPI3REF: Constants Defining Special Destructor Behavior 3415** 3416** These are special values for the destructor that is passed in as the 3417** final argument to routines like [sqlite3_result_blob()]. ^If the destructor 3418** argument is SQLITE_STATIC, it means that the content pointer is constant 3419** and will never change. It does not need to be destroyed. ^The 3420** SQLITE_TRANSIENT value means that the content will likely change in 3421** the near future and that SQLite should make its own private copy of 3422** the content before returning. 3423** 3424** The typedef is necessary to work around problems in certain 3425** C++ compilers. See ticket #2191. 3426*/ 3427typedef void (*sqlite3_destructor_type)(void*); 3428#define SQLITE_STATIC ((sqlite3_destructor_type)0) 3429#define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) 3430 3431/* 3432** CAPI3REF: Setting The Result Of An SQL Function 3433** 3434** These routines are used by the xFunc or xFinal callbacks that 3435** implement SQL functions and aggregates. See 3436** [sqlite3_create_function()] and [sqlite3_create_function16()] 3437** for additional information. 3438** 3439** These functions work very much like the [parameter binding] family of 3440** functions used to bind values to host parameters in prepared statements. 3441** Refer to the [SQL parameter] documentation for additional information. 3442** 3443** ^The sqlite3_result_blob() interface sets the result from 3444** an application-defined function to be the BLOB whose content is pointed 3445** to by the second parameter and which is N bytes long where N is the 3446** third parameter. 3447** 3448** ^The sqlite3_result_zeroblob() interfaces set the result of 3449** the application-defined function to be a BLOB containing all zero 3450** bytes and N bytes in size, where N is the value of the 2nd parameter. 3451** 3452** ^The sqlite3_result_double() interface sets the result from 3453** an application-defined function to be a floating point value specified 3454** by its 2nd argument. 3455** 3456** ^The sqlite3_result_error() and sqlite3_result_error16() functions 3457** cause the implemented SQL function to throw an exception. 3458** ^SQLite uses the string pointed to by the 3459** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() 3460** as the text of an error message. ^SQLite interprets the error 3461** message string from sqlite3_result_error() as UTF-8. ^SQLite 3462** interprets the string from sqlite3_result_error16() as UTF-16 in native 3463** byte order. ^If the third parameter to sqlite3_result_error() 3464** or sqlite3_result_error16() is negative then SQLite takes as the error 3465** message all text up through the first zero character. 3466** ^If the third parameter to sqlite3_result_error() or 3467** sqlite3_result_error16() is non-negative then SQLite takes that many 3468** bytes (not characters) from the 2nd parameter as the error message. 3469** ^The sqlite3_result_error() and sqlite3_result_error16() 3470** routines make a private copy of the error message text before 3471** they return. Hence, the calling function can deallocate or 3472** modify the text after they return without harm. 3473** ^The sqlite3_result_error_code() function changes the error code 3474** returned by SQLite as a result of an error in a function. ^By default, 3475** the error code is SQLITE_ERROR. ^A subsequent call to sqlite3_result_error() 3476** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. 3477** 3478** ^The sqlite3_result_toobig() interface causes SQLite to throw an error 3479** indicating that a string or BLOB is too long to represent. 3480** 3481** ^The sqlite3_result_nomem() interface causes SQLite to throw an error 3482** indicating that a memory allocation failed. 3483** 3484** ^The sqlite3_result_int() interface sets the return value 3485** of the application-defined function to be the 32-bit signed integer 3486** value given in the 2nd argument. 3487** ^The sqlite3_result_int64() interface sets the return value 3488** of the application-defined function to be the 64-bit signed integer 3489** value given in the 2nd argument. 3490** 3491** ^The sqlite3_result_null() interface sets the return value 3492** of the application-defined function to be NULL. 3493** 3494** ^The sqlite3_result_text(), sqlite3_result_text16(), 3495** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces 3496** set the return value of the application-defined function to be 3497** a text string which is represented as UTF-8, UTF-16 native byte order, 3498** UTF-16 little endian, or UTF-16 big endian, respectively. 3499** ^SQLite takes the text result from the application from 3500** the 2nd parameter of the sqlite3_result_text* interfaces. 3501** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3502** is negative, then SQLite takes result text from the 2nd parameter 3503** through the first zero character. 3504** ^If the 3rd parameter to the sqlite3_result_text* interfaces 3505** is non-negative, then as many bytes (not characters) of the text 3506** pointed to by the 2nd parameter are taken as the application-defined 3507** function result. 3508** ^If the 4th parameter to the sqlite3_result_text* interfaces 3509** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that 3510** function as the destructor on the text or BLOB result when it has 3511** finished using that result. 3512** ^If the 4th parameter to the sqlite3_result_text* interfaces or to 3513** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite 3514** assumes that the text or BLOB result is in constant space and does not 3515** copy the content of the parameter nor call a destructor on the content 3516** when it has finished using that result. 3517** ^If the 4th parameter to the sqlite3_result_text* interfaces 3518** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT 3519** then SQLite makes a copy of the result into space obtained from 3520** from [sqlite3_malloc()] before it returns. 3521** 3522** ^The sqlite3_result_value() interface sets the result of 3523** the application-defined function to be a copy the 3524** [unprotected sqlite3_value] object specified by the 2nd parameter. ^The 3525** sqlite3_result_value() interface makes a copy of the [sqlite3_value] 3526** so that the [sqlite3_value] specified in the parameter may change or 3527** be deallocated after sqlite3_result_value() returns without harm. 3528** ^A [protected sqlite3_value] object may always be used where an 3529** [unprotected sqlite3_value] object is required, so either 3530** kind of [sqlite3_value] object can be used with this interface. 3531** 3532** If these routines are called from within the different thread 3533** than the one containing the application-defined function that received 3534** the [sqlite3_context] pointer, the results are undefined. 3535*/ 3536void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); 3537void sqlite3_result_double(sqlite3_context*, double); 3538void sqlite3_result_error(sqlite3_context*, const char*, int); 3539void sqlite3_result_error16(sqlite3_context*, const void*, int); 3540void sqlite3_result_error_toobig(sqlite3_context*); 3541void sqlite3_result_error_nomem(sqlite3_context*); 3542void sqlite3_result_error_code(sqlite3_context*, int); 3543void sqlite3_result_int(sqlite3_context*, int); 3544void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); 3545void sqlite3_result_null(sqlite3_context*); 3546void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); 3547void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); 3548void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); 3549void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); 3550void sqlite3_result_value(sqlite3_context*, sqlite3_value*); 3551void sqlite3_result_zeroblob(sqlite3_context*, int n); 3552 3553/* 3554** CAPI3REF: Define New Collating Sequences 3555** 3556** These functions are used to add new collation sequences to the 3557** [database connection] specified as the first argument. 3558** 3559** ^The name of the new collation sequence is specified as a UTF-8 string 3560** for sqlite3_create_collation() and sqlite3_create_collation_v2() 3561** and a UTF-16 string for sqlite3_create_collation16(). ^In all cases 3562** the name is passed as the second function argument. 3563** 3564** ^The third argument may be one of the constants [SQLITE_UTF8], 3565** [SQLITE_UTF16LE], or [SQLITE_UTF16BE], indicating that the user-supplied 3566** routine expects to be passed pointers to strings encoded using UTF-8, 3567** UTF-16 little-endian, or UTF-16 big-endian, respectively. ^The 3568** third argument might also be [SQLITE_UTF16] to indicate that the routine 3569** expects pointers to be UTF-16 strings in the native byte order, or the 3570** argument can be [SQLITE_UTF16_ALIGNED] if the 3571** the routine expects pointers to 16-bit word aligned strings 3572** of UTF-16 in the native byte order. 3573** 3574** A pointer to the user supplied routine must be passed as the fifth 3575** argument. ^If it is NULL, this is the same as deleting the collation 3576** sequence (so that SQLite cannot call it anymore). 3577** ^Each time the application supplied function is invoked, it is passed 3578** as its first parameter a copy of the void* passed as the fourth argument 3579** to sqlite3_create_collation() or sqlite3_create_collation16(). 3580** 3581** ^The remaining arguments to the application-supplied routine are two strings, 3582** each represented by a (length, data) pair and encoded in the encoding 3583** that was passed as the third argument when the collation sequence was 3584** registered. The application defined collation routine should 3585** return negative, zero or positive if the first string is less than, 3586** equal to, or greater than the second string. i.e. (STRING1 - STRING2). 3587** 3588** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation() 3589** except that it takes an extra argument which is a destructor for 3590** the collation. ^The destructor is called when the collation is 3591** destroyed and is passed a copy of the fourth parameter void* pointer 3592** of the sqlite3_create_collation_v2(). 3593** ^Collations are destroyed when they are overridden by later calls to the 3594** collation creation functions or when the [database connection] is closed 3595** using [sqlite3_close()]. 3596** 3597** See also: [sqlite3_collation_needed()] and [sqlite3_collation_needed16()]. 3598*/ 3599int sqlite3_create_collation( 3600 sqlite3*, 3601 const char *zName, 3602 int eTextRep, 3603 void*, 3604 int(*xCompare)(void*,int,const void*,int,const void*) 3605); 3606int sqlite3_create_collation_v2( 3607 sqlite3*, 3608 const char *zName, 3609 int eTextRep, 3610 void*, 3611 int(*xCompare)(void*,int,const void*,int,const void*), 3612 void(*xDestroy)(void*) 3613); 3614int sqlite3_create_collation16( 3615 sqlite3*, 3616 const void *zName, 3617 int eTextRep, 3618 void*, 3619 int(*xCompare)(void*,int,const void*,int,const void*) 3620); 3621 3622/* 3623** CAPI3REF: Collation Needed Callbacks 3624** 3625** ^To avoid having to register all collation sequences before a database 3626** can be used, a single callback function may be registered with the 3627** [database connection] to be invoked whenever an undefined collation 3628** sequence is required. 3629** 3630** ^If the function is registered using the sqlite3_collation_needed() API, 3631** then it is passed the names of undefined collation sequences as strings 3632** encoded in UTF-8. ^If sqlite3_collation_needed16() is used, 3633** the names are passed as UTF-16 in machine native byte order. 3634** ^A call to either function replaces the existing collation-needed callback. 3635** 3636** ^(When the callback is invoked, the first argument passed is a copy 3637** of the second argument to sqlite3_collation_needed() or 3638** sqlite3_collation_needed16(). The second argument is the database 3639** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], 3640** or [SQLITE_UTF16LE], indicating the most desirable form of the collation 3641** sequence function required. The fourth parameter is the name of the 3642** required collation sequence.)^ 3643** 3644** The callback function should register the desired collation using 3645** [sqlite3_create_collation()], [sqlite3_create_collation16()], or 3646** [sqlite3_create_collation_v2()]. 3647*/ 3648int sqlite3_collation_needed( 3649 sqlite3*, 3650 void*, 3651 void(*)(void*,sqlite3*,int eTextRep,const char*) 3652); 3653int sqlite3_collation_needed16( 3654 sqlite3*, 3655 void*, 3656 void(*)(void*,sqlite3*,int eTextRep,const void*) 3657); 3658 3659/* 3660** Specify the key for an encrypted database. This routine should be 3661** called right after sqlite3_open(). 3662** 3663** The code to implement this API is not available in the public release 3664** of SQLite. 3665*/ 3666int sqlite3_key( 3667 sqlite3 *db, /* Database to be rekeyed */ 3668 const void *pKey, int nKey /* The key */ 3669); 3670 3671/* 3672** Change the key on an open database. If the current database is not 3673** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the 3674** database is decrypted. 3675** 3676** The code to implement this API is not available in the public release 3677** of SQLite. 3678*/ 3679int sqlite3_rekey( 3680 sqlite3 *db, /* Database to be rekeyed */ 3681 const void *pKey, int nKey /* The new key */ 3682); 3683 3684/* 3685** CAPI3REF: Suspend Execution For A Short Time 3686** 3687** ^The sqlite3_sleep() function causes the current thread to suspend execution 3688** for at least a number of milliseconds specified in its parameter. 3689** 3690** ^If the operating system does not support sleep requests with 3691** millisecond time resolution, then the time will be rounded up to 3692** the nearest second. ^The number of milliseconds of sleep actually 3693** requested from the operating system is returned. 3694** 3695** ^SQLite implements this interface by calling the xSleep() 3696** method of the default [sqlite3_vfs] object. 3697*/ 3698int sqlite3_sleep(int); 3699 3700/* 3701** CAPI3REF: Name Of The Folder Holding Temporary Files 3702** 3703** ^(If this global variable is made to point to a string which is 3704** the name of a folder (a.k.a. directory), then all temporary files 3705** created by SQLite when using a built-in [sqlite3_vfs | VFS] 3706** will be placed in that directory.)^ ^If this variable 3707** is a NULL pointer, then SQLite performs a search for an appropriate 3708** temporary file directory. 3709** 3710** It is not safe to read or modify this variable in more than one 3711** thread at a time. It is not safe to read or modify this variable 3712** if a [database connection] is being used at the same time in a separate 3713** thread. 3714** It is intended that this variable be set once 3715** as part of process initialization and before any SQLite interface 3716** routines have been called and that this variable remain unchanged 3717** thereafter. 3718** 3719** ^The [temp_store_directory pragma] may modify this variable and cause 3720** it to point to memory obtained from [sqlite3_malloc]. ^Furthermore, 3721** the [temp_store_directory pragma] always assumes that any string 3722** that this variable points to is held in memory obtained from 3723** [sqlite3_malloc] and the pragma may attempt to free that memory 3724** using [sqlite3_free]. 3725** Hence, if this variable is modified directly, either it should be 3726** made NULL or made to point to memory obtained from [sqlite3_malloc] 3727** or else the use of the [temp_store_directory pragma] should be avoided. 3728*/ 3729SQLITE_EXTERN char *sqlite3_temp_directory; 3730 3731/* 3732** CAPI3REF: Test For Auto-Commit Mode 3733** KEYWORDS: {autocommit mode} 3734** 3735** ^The sqlite3_get_autocommit() interface returns non-zero or 3736** zero if the given database connection is or is not in autocommit mode, 3737** respectively. ^Autocommit mode is on by default. 3738** ^Autocommit mode is disabled by a [BEGIN] statement. 3739** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. 3740** 3741** If certain kinds of errors occur on a statement within a multi-statement 3742** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], 3743** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the 3744** transaction might be rolled back automatically. The only way to 3745** find out whether SQLite automatically rolled back the transaction after 3746** an error is to use this function. 3747** 3748** If another thread changes the autocommit status of the database 3749** connection while this routine is running, then the return value 3750** is undefined. 3751*/ 3752int sqlite3_get_autocommit(sqlite3*); 3753 3754/* 3755** CAPI3REF: Find The Database Handle Of A Prepared Statement 3756** 3757** ^The sqlite3_db_handle interface returns the [database connection] handle 3758** to which a [prepared statement] belongs. ^The [database connection] 3759** returned by sqlite3_db_handle is the same [database connection] 3760** that was the first argument 3761** to the [sqlite3_prepare_v2()] call (or its variants) that was used to 3762** create the statement in the first place. 3763*/ 3764sqlite3 *sqlite3_db_handle(sqlite3_stmt*); 3765 3766/* 3767** CAPI3REF: Find the next prepared statement 3768** 3769** ^This interface returns a pointer to the next [prepared statement] after 3770** pStmt associated with the [database connection] pDb. ^If pStmt is NULL 3771** then this interface returns a pointer to the first prepared statement 3772** associated with the database connection pDb. ^If no prepared statement 3773** satisfies the conditions of this routine, it returns NULL. 3774** 3775** The [database connection] pointer D in a call to 3776** [sqlite3_next_stmt(D,S)] must refer to an open database 3777** connection and in particular must not be a NULL pointer. 3778*/ 3779sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); 3780 3781/* 3782** CAPI3REF: Commit And Rollback Notification Callbacks 3783** 3784** ^The sqlite3_commit_hook() interface registers a callback 3785** function to be invoked whenever a transaction is [COMMIT | committed]. 3786** ^Any callback set by a previous call to sqlite3_commit_hook() 3787** for the same database connection is overridden. 3788** ^The sqlite3_rollback_hook() interface registers a callback 3789** function to be invoked whenever a transaction is [ROLLBACK | rolled back]. 3790** ^Any callback set by a previous call to sqlite3_rollback_hook() 3791** for the same database connection is overridden. 3792** ^The pArg argument is passed through to the callback. 3793** ^If the callback on a commit hook function returns non-zero, 3794** then the commit is converted into a rollback. 3795** 3796** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions 3797** return the P argument from the previous call of the same function 3798** on the same [database connection] D, or NULL for 3799** the first call for each function on D. 3800** 3801** The callback implementation must not do anything that will modify 3802** the database connection that invoked the callback. Any actions 3803** to modify the database connection must be deferred until after the 3804** completion of the [sqlite3_step()] call that triggered the commit 3805** or rollback hook in the first place. 3806** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3807** database connections for the meaning of "modify" in this paragraph. 3808** 3809** ^Registering a NULL function disables the callback. 3810** 3811** ^When the commit hook callback routine returns zero, the [COMMIT] 3812** operation is allowed to continue normally. ^If the commit hook 3813** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK]. 3814** ^The rollback hook is invoked on a rollback that results from a commit 3815** hook returning non-zero, just as it would be with any other rollback. 3816** 3817** ^For the purposes of this API, a transaction is said to have been 3818** rolled back if an explicit "ROLLBACK" statement is executed, or 3819** an error or constraint causes an implicit rollback to occur. 3820** ^The rollback callback is not invoked if a transaction is 3821** automatically rolled back because the database connection is closed. 3822** ^The rollback callback is not invoked if a transaction is 3823** rolled back because a commit callback returned non-zero. 3824** 3825** See also the [sqlite3_update_hook()] interface. 3826*/ 3827void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); 3828void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); 3829 3830/* 3831** CAPI3REF: Data Change Notification Callbacks 3832** 3833** ^The sqlite3_update_hook() interface registers a callback function 3834** with the [database connection] identified by the first argument 3835** to be invoked whenever a row is updated, inserted or deleted. 3836** ^Any callback set by a previous call to this function 3837** for the same database connection is overridden. 3838** 3839** ^The second argument is a pointer to the function to invoke when a 3840** row is updated, inserted or deleted. 3841** ^The first argument to the callback is a copy of the third argument 3842** to sqlite3_update_hook(). 3843** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], 3844** or [SQLITE_UPDATE], depending on the operation that caused the callback 3845** to be invoked. 3846** ^The third and fourth arguments to the callback contain pointers to the 3847** database and table name containing the affected row. 3848** ^The final callback parameter is the [rowid] of the row. 3849** ^In the case of an update, this is the [rowid] after the update takes place. 3850** 3851** ^(The update hook is not invoked when internal system tables are 3852** modified (i.e. sqlite_master and sqlite_sequence).)^ 3853** 3854** ^In the current implementation, the update hook 3855** is not invoked when duplication rows are deleted because of an 3856** [ON CONFLICT | ON CONFLICT REPLACE] clause. ^Nor is the update hook 3857** invoked when rows are deleted using the [truncate optimization]. 3858** The exceptions defined in this paragraph might change in a future 3859** release of SQLite. 3860** 3861** The update hook implementation must not do anything that will modify 3862** the database connection that invoked the update hook. Any actions 3863** to modify the database connection must be deferred until after the 3864** completion of the [sqlite3_step()] call that triggered the update hook. 3865** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their 3866** database connections for the meaning of "modify" in this paragraph. 3867** 3868** ^The sqlite3_update_hook(D,C,P) function 3869** returns the P argument from the previous call 3870** on the same [database connection] D, or NULL for 3871** the first call on D. 3872** 3873** See also the [sqlite3_commit_hook()] and [sqlite3_rollback_hook()] 3874** interfaces. 3875*/ 3876void *sqlite3_update_hook( 3877 sqlite3*, 3878 void(*)(void *,int ,char const *,char const *,sqlite3_int64), 3879 void* 3880); 3881 3882/* 3883** CAPI3REF: Enable Or Disable Shared Pager Cache 3884** KEYWORDS: {shared cache} 3885** 3886** ^(This routine enables or disables the sharing of the database cache 3887** and schema data structures between [database connection | connections] 3888** to the same database. Sharing is enabled if the argument is true 3889** and disabled if the argument is false.)^ 3890** 3891** ^Cache sharing is enabled and disabled for an entire process. 3892** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, 3893** sharing was enabled or disabled for each thread separately. 3894** 3895** ^(The cache sharing mode set by this interface effects all subsequent 3896** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. 3897** Existing database connections continue use the sharing mode 3898** that was in effect at the time they were opened.)^ 3899** 3900** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled 3901** successfully. An [error code] is returned otherwise.)^ 3902** 3903** ^Shared cache is disabled by default. But this might change in 3904** future releases of SQLite. Applications that care about shared 3905** cache setting should set it explicitly. 3906** 3907** See Also: [SQLite Shared-Cache Mode] 3908*/ 3909int sqlite3_enable_shared_cache(int); 3910 3911/* 3912** CAPI3REF: Attempt To Free Heap Memory 3913** 3914** ^The sqlite3_release_memory() interface attempts to free N bytes 3915** of heap memory by deallocating non-essential memory allocations 3916** held by the database library. Memory used to cache database 3917** pages to improve performance is an example of non-essential memory. 3918** ^sqlite3_release_memory() returns the number of bytes actually freed, 3919** which might be more or less than the amount requested. 3920*/ 3921int sqlite3_release_memory(int); 3922 3923/* 3924** CAPI3REF: Impose A Limit On Heap Size 3925** 3926** ^The sqlite3_soft_heap_limit() interface places a "soft" limit 3927** on the amount of heap memory that may be allocated by SQLite. 3928** ^If an internal allocation is requested that would exceed the 3929** soft heap limit, [sqlite3_release_memory()] is invoked one or 3930** more times to free up some space before the allocation is performed. 3931** 3932** ^The limit is called "soft" because if [sqlite3_release_memory()] 3933** cannot free sufficient memory to prevent the limit from being exceeded, 3934** the memory is allocated anyway and the current operation proceeds. 3935** 3936** ^A negative or zero value for N means that there is no soft heap limit and 3937** [sqlite3_release_memory()] will only be called when memory is exhausted. 3938** ^The default value for the soft heap limit is zero. 3939** 3940** ^(SQLite makes a best effort to honor the soft heap limit. 3941** But if the soft heap limit cannot be honored, execution will 3942** continue without error or notification.)^ This is why the limit is 3943** called a "soft" limit. It is advisory only. 3944** 3945** Prior to SQLite version 3.5.0, this routine only constrained the memory 3946** allocated by a single thread - the same thread in which this routine 3947** runs. Beginning with SQLite version 3.5.0, the soft heap limit is 3948** applied to all threads. The value specified for the soft heap limit 3949** is an upper bound on the total memory allocation for all threads. In 3950** version 3.5.0 there is no mechanism for limiting the heap usage for 3951** individual threads. 3952*/ 3953void sqlite3_soft_heap_limit(int); 3954 3955/* 3956** CAPI3REF: Extract Metadata About A Column Of A Table 3957** 3958** ^This routine returns metadata about a specific column of a specific 3959** database table accessible using the [database connection] handle 3960** passed as the first function argument. 3961** 3962** ^The column is identified by the second, third and fourth parameters to 3963** this function. ^The second parameter is either the name of the database 3964** (i.e. "main", "temp", or an attached database) containing the specified 3965** table or NULL. ^If it is NULL, then all attached databases are searched 3966** for the table using the same algorithm used by the database engine to 3967** resolve unqualified table references. 3968** 3969** ^The third and fourth parameters to this function are the table and column 3970** name of the desired column, respectively. Neither of these parameters 3971** may be NULL. 3972** 3973** ^Metadata is returned by writing to the memory locations passed as the 5th 3974** and subsequent parameters to this function. ^Any of these arguments may be 3975** NULL, in which case the corresponding element of metadata is omitted. 3976** 3977** ^(<blockquote> 3978** <table border="1"> 3979** <tr><th> Parameter <th> Output<br>Type <th> Description 3980** 3981** <tr><td> 5th <td> const char* <td> Data type 3982** <tr><td> 6th <td> const char* <td> Name of default collation sequence 3983** <tr><td> 7th <td> int <td> True if column has a NOT NULL constraint 3984** <tr><td> 8th <td> int <td> True if column is part of the PRIMARY KEY 3985** <tr><td> 9th <td> int <td> True if column is [AUTOINCREMENT] 3986** </table> 3987** </blockquote>)^ 3988** 3989** ^The memory pointed to by the character pointers returned for the 3990** declaration type and collation sequence is valid only until the next 3991** call to any SQLite API function. 3992** 3993** ^If the specified table is actually a view, an [error code] is returned. 3994** 3995** ^If the specified column is "rowid", "oid" or "_rowid_" and an 3996** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output 3997** parameters are set for the explicitly declared column. ^(If there is no 3998** explicitly declared [INTEGER PRIMARY KEY] column, then the output 3999** parameters are set as follows: 4000** 4001** <pre> 4002** data type: "INTEGER" 4003** collation sequence: "BINARY" 4004** not null: 0 4005** primary key: 1 4006** auto increment: 0 4007** </pre>)^ 4008** 4009** ^(This function may load one or more schemas from database files. If an 4010** error occurs during this process, or if the requested table or column 4011** cannot be found, an [error code] is returned and an error message left 4012** in the [database connection] (to be retrieved using sqlite3_errmsg()).)^ 4013** 4014** ^This API is only available if the library was compiled with the 4015** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. 4016*/ 4017int sqlite3_table_column_metadata( 4018 sqlite3 *db, /* Connection handle */ 4019 const char *zDbName, /* Database name or NULL */ 4020 const char *zTableName, /* Table name */ 4021 const char *zColumnName, /* Column name */ 4022 char const **pzDataType, /* OUTPUT: Declared data type */ 4023 char const **pzCollSeq, /* OUTPUT: Collation sequence name */ 4024 int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ 4025 int *pPrimaryKey, /* OUTPUT: True if column part of PK */ 4026 int *pAutoinc /* OUTPUT: True if column is auto-increment */ 4027); 4028 4029/* 4030** CAPI3REF: Load An Extension 4031** 4032** ^This interface loads an SQLite extension library from the named file. 4033** 4034** ^The sqlite3_load_extension() interface attempts to load an 4035** SQLite extension library contained in the file zFile. 4036** 4037** ^The entry point is zProc. 4038** ^zProc may be 0, in which case the name of the entry point 4039** defaults to "sqlite3_extension_init". 4040** ^The sqlite3_load_extension() interface returns 4041** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. 4042** ^If an error occurs and pzErrMsg is not 0, then the 4043** [sqlite3_load_extension()] interface shall attempt to 4044** fill *pzErrMsg with error message text stored in memory 4045** obtained from [sqlite3_malloc()]. The calling function 4046** should free this memory by calling [sqlite3_free()]. 4047** 4048** ^Extension loading must be enabled using 4049** [sqlite3_enable_load_extension()] prior to calling this API, 4050** otherwise an error will be returned. 4051** 4052** See also the [load_extension() SQL function]. 4053*/ 4054int sqlite3_load_extension( 4055 sqlite3 *db, /* Load the extension into this database connection */ 4056 const char *zFile, /* Name of the shared library containing extension */ 4057 const char *zProc, /* Entry point. Derived from zFile if 0 */ 4058 char **pzErrMsg /* Put error message here if not 0 */ 4059); 4060 4061/* 4062** CAPI3REF: Enable Or Disable Extension Loading 4063** 4064** ^So as not to open security holes in older applications that are 4065** unprepared to deal with extension loading, and as a means of disabling 4066** extension loading while evaluating user-entered SQL, the following API 4067** is provided to turn the [sqlite3_load_extension()] mechanism on and off. 4068** 4069** ^Extension loading is off by default. See ticket #1863. 4070** ^Call the sqlite3_enable_load_extension() routine with onoff==1 4071** to turn extension loading on and call it with onoff==0 to turn 4072** it back off again. 4073*/ 4074int sqlite3_enable_load_extension(sqlite3 *db, int onoff); 4075 4076/* 4077** CAPI3REF: Automatically Load An Extensions 4078** 4079** ^This API can be invoked at program startup in order to register 4080** one or more statically linked extensions that will be available 4081** to all new [database connections]. 4082** 4083** ^(This routine stores a pointer to the extension entry point 4084** in an array that is obtained from [sqlite3_malloc()]. That memory 4085** is deallocated by [sqlite3_reset_auto_extension()].)^ 4086** 4087** ^This function registers an extension entry point that is 4088** automatically invoked whenever a new [database connection] 4089** is opened using [sqlite3_open()], [sqlite3_open16()], 4090** or [sqlite3_open_v2()]. 4091** ^Duplicate extensions are detected so calling this routine 4092** multiple times with the same extension is harmless. 4093** ^Automatic extensions apply across all threads. 4094*/ 4095int sqlite3_auto_extension(void (*xEntryPoint)(void)); 4096 4097/* 4098** CAPI3REF: Reset Automatic Extension Loading 4099** 4100** ^(This function disables all previously registered automatic 4101** extensions. It undoes the effect of all prior 4102** [sqlite3_auto_extension()] calls.)^ 4103** 4104** ^This function disables automatic extensions in all threads. 4105*/ 4106void sqlite3_reset_auto_extension(void); 4107 4108/* 4109****** EXPERIMENTAL - subject to change without notice ************** 4110** 4111** The interface to the virtual-table mechanism is currently considered 4112** to be experimental. The interface might change in incompatible ways. 4113** If this is a problem for you, do not use the interface at this time. 4114** 4115** When the virtual-table mechanism stabilizes, we will declare the 4116** interface fixed, support it indefinitely, and remove this comment. 4117*/ 4118 4119/* 4120** Structures used by the virtual table interface 4121*/ 4122typedef struct sqlite3_vtab sqlite3_vtab; 4123typedef struct sqlite3_index_info sqlite3_index_info; 4124typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; 4125typedef struct sqlite3_module sqlite3_module; 4126 4127/* 4128** CAPI3REF: Virtual Table Object 4129** KEYWORDS: sqlite3_module {virtual table module} 4130** EXPERIMENTAL 4131** 4132** This structure, sometimes called a a "virtual table module", 4133** defines the implementation of a [virtual tables]. 4134** This structure consists mostly of methods for the module. 4135** 4136** ^A virtual table module is created by filling in a persistent 4137** instance of this structure and passing a pointer to that instance 4138** to [sqlite3_create_module()] or [sqlite3_create_module_v2()]. 4139** ^The registration remains valid until it is replaced by a different 4140** module or until the [database connection] closes. The content 4141** of this structure must not change while it is registered with 4142** any database connection. 4143*/ 4144struct sqlite3_module { 4145 int iVersion; 4146 int (*xCreate)(sqlite3*, void *pAux, 4147 int argc, const char *const*argv, 4148 sqlite3_vtab **ppVTab, char**); 4149 int (*xConnect)(sqlite3*, void *pAux, 4150 int argc, const char *const*argv, 4151 sqlite3_vtab **ppVTab, char**); 4152 int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); 4153 int (*xDisconnect)(sqlite3_vtab *pVTab); 4154 int (*xDestroy)(sqlite3_vtab *pVTab); 4155 int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); 4156 int (*xClose)(sqlite3_vtab_cursor*); 4157 int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, 4158 int argc, sqlite3_value **argv); 4159 int (*xNext)(sqlite3_vtab_cursor*); 4160 int (*xEof)(sqlite3_vtab_cursor*); 4161 int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); 4162 int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); 4163 int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); 4164 int (*xBegin)(sqlite3_vtab *pVTab); 4165 int (*xSync)(sqlite3_vtab *pVTab); 4166 int (*xCommit)(sqlite3_vtab *pVTab); 4167 int (*xRollback)(sqlite3_vtab *pVTab); 4168 int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, 4169 void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), 4170 void **ppArg); 4171 int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); 4172}; 4173 4174/* 4175** CAPI3REF: Virtual Table Indexing Information 4176** KEYWORDS: sqlite3_index_info 4177** EXPERIMENTAL 4178** 4179** The sqlite3_index_info structure and its substructures is used to 4180** pass information into and receive the reply from the [xBestIndex] 4181** method of a [virtual table module]. The fields under **Inputs** are the 4182** inputs to xBestIndex and are read-only. xBestIndex inserts its 4183** results into the **Outputs** fields. 4184** 4185** ^(The aConstraint[] array records WHERE clause constraints of the form: 4186** 4187** <pre>column OP expr</pre> 4188** 4189** where OP is =, <, <=, >, or >=.)^ ^(The particular operator is 4190** stored in aConstraint[].op.)^ ^(The index of the column is stored in 4191** aConstraint[].iColumn.)^ ^(aConstraint[].usable is TRUE if the 4192** expr on the right-hand side can be evaluated (and thus the constraint 4193** is usable) and false if it cannot.)^ 4194** 4195** ^The optimizer automatically inverts terms of the form "expr OP column" 4196** and makes other simplifications to the WHERE clause in an attempt to 4197** get as many WHERE clause terms into the form shown above as possible. 4198** ^The aConstraint[] array only reports WHERE clause terms that are 4199** relevant to the particular virtual table being queried. 4200** 4201** ^Information about the ORDER BY clause is stored in aOrderBy[]. 4202** ^Each term of aOrderBy records a column of the ORDER BY clause. 4203** 4204** The [xBestIndex] method must fill aConstraintUsage[] with information 4205** about what parameters to pass to xFilter. ^If argvIndex>0 then 4206** the right-hand side of the corresponding aConstraint[] is evaluated 4207** and becomes the argvIndex-th entry in argv. ^(If aConstraintUsage[].omit 4208** is true, then the constraint is assumed to be fully handled by the 4209** virtual table and is not checked again by SQLite.)^ 4210** 4211** ^The idxNum and idxPtr values are recorded and passed into the 4212** [xFilter] method. 4213** ^[sqlite3_free()] is used to free idxPtr if and only if 4214** needToFreeIdxPtr is true. 4215** 4216** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in 4217** the correct order to satisfy the ORDER BY clause so that no separate 4218** sorting step is required. 4219** 4220** ^The estimatedCost value is an estimate of the cost of doing the 4221** particular lookup. A full scan of a table with N entries should have 4222** a cost of N. A binary search of a table of N entries should have a 4223** cost of approximately log(N). 4224*/ 4225struct sqlite3_index_info { 4226 /* Inputs */ 4227 int nConstraint; /* Number of entries in aConstraint */ 4228 struct sqlite3_index_constraint { 4229 int iColumn; /* Column on left-hand side of constraint */ 4230 unsigned char op; /* Constraint operator */ 4231 unsigned char usable; /* True if this constraint is usable */ 4232 int iTermOffset; /* Used internally - xBestIndex should ignore */ 4233 } *aConstraint; /* Table of WHERE clause constraints */ 4234 int nOrderBy; /* Number of terms in the ORDER BY clause */ 4235 struct sqlite3_index_orderby { 4236 int iColumn; /* Column number */ 4237 unsigned char desc; /* True for DESC. False for ASC. */ 4238 } *aOrderBy; /* The ORDER BY clause */ 4239 /* Outputs */ 4240 struct sqlite3_index_constraint_usage { 4241 int argvIndex; /* if >0, constraint is part of argv to xFilter */ 4242 unsigned char omit; /* Do not code a test for this constraint */ 4243 } *aConstraintUsage; 4244 int idxNum; /* Number used to identify the index */ 4245 char *idxStr; /* String, possibly obtained from sqlite3_malloc */ 4246 int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ 4247 int orderByConsumed; /* True if output is already ordered */ 4248 double estimatedCost; /* Estimated cost of using this index */ 4249}; 4250#define SQLITE_INDEX_CONSTRAINT_EQ 2 4251#define SQLITE_INDEX_CONSTRAINT_GT 4 4252#define SQLITE_INDEX_CONSTRAINT_LE 8 4253#define SQLITE_INDEX_CONSTRAINT_LT 16 4254#define SQLITE_INDEX_CONSTRAINT_GE 32 4255#define SQLITE_INDEX_CONSTRAINT_MATCH 64 4256 4257/* 4258** CAPI3REF: Register A Virtual Table Implementation 4259** EXPERIMENTAL 4260** 4261** ^These routines are used to register a new [virtual table module] name. 4262** ^Module names must be registered before 4263** creating a new [virtual table] using the module and before using a 4264** preexisting [virtual table] for the module. 4265** 4266** ^The module name is registered on the [database connection] specified 4267** by the first parameter. ^The name of the module is given by the 4268** second parameter. ^The third parameter is a pointer to 4269** the implementation of the [virtual table module]. ^The fourth 4270** parameter is an arbitrary client data pointer that is passed through 4271** into the [xCreate] and [xConnect] methods of the virtual table module 4272** when a new virtual table is be being created or reinitialized. 4273** 4274** ^The sqlite3_create_module_v2() interface has a fifth parameter which 4275** is a pointer to a destructor for the pClientData. ^SQLite will 4276** invoke the destructor function (if it is not NULL) when SQLite 4277** no longer needs the pClientData pointer. ^The sqlite3_create_module() 4278** interface is equivalent to sqlite3_create_module_v2() with a NULL 4279** destructor. 4280*/ 4281SQLITE_EXPERIMENTAL int sqlite3_create_module( 4282 sqlite3 *db, /* SQLite connection to register module with */ 4283 const char *zName, /* Name of the module */ 4284 const sqlite3_module *p, /* Methods for the module */ 4285 void *pClientData /* Client data for xCreate/xConnect */ 4286); 4287SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( 4288 sqlite3 *db, /* SQLite connection to register module with */ 4289 const char *zName, /* Name of the module */ 4290 const sqlite3_module *p, /* Methods for the module */ 4291 void *pClientData, /* Client data for xCreate/xConnect */ 4292 void(*xDestroy)(void*) /* Module destructor function */ 4293); 4294 4295/* 4296** CAPI3REF: Virtual Table Instance Object 4297** KEYWORDS: sqlite3_vtab 4298** EXPERIMENTAL 4299** 4300** Every [virtual table module] implementation uses a subclass 4301** of this object to describe a particular instance 4302** of the [virtual table]. Each subclass will 4303** be tailored to the specific needs of the module implementation. 4304** The purpose of this superclass is to define certain fields that are 4305** common to all module implementations. 4306** 4307** ^Virtual tables methods can set an error message by assigning a 4308** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should 4309** take care that any prior string is freed by a call to [sqlite3_free()] 4310** prior to assigning a new string to zErrMsg. ^After the error message 4311** is delivered up to the client application, the string will be automatically 4312** freed by sqlite3_free() and the zErrMsg field will be zeroed. 4313*/ 4314struct sqlite3_vtab { 4315 const sqlite3_module *pModule; /* The module for this virtual table */ 4316 int nRef; /* NO LONGER USED */ 4317 char *zErrMsg; /* Error message from sqlite3_mprintf() */ 4318 /* Virtual table implementations will typically add additional fields */ 4319}; 4320 4321/* 4322** CAPI3REF: Virtual Table Cursor Object 4323** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor} 4324** EXPERIMENTAL 4325** 4326** Every [virtual table module] implementation uses a subclass of the 4327** following structure to describe cursors that point into the 4328** [virtual table] and are used 4329** to loop through the virtual table. Cursors are created using the 4330** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed 4331** by the [sqlite3_module.xClose | xClose] method. Cursors are used 4332** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods 4333** of the module. Each module implementation will define 4334** the content of a cursor structure to suit its own needs. 4335** 4336** This superclass exists in order to define fields of the cursor that 4337** are common to all implementations. 4338*/ 4339struct sqlite3_vtab_cursor { 4340 sqlite3_vtab *pVtab; /* Virtual table of this cursor */ 4341 /* Virtual table implementations will typically add additional fields */ 4342}; 4343 4344/* 4345** CAPI3REF: Declare The Schema Of A Virtual Table 4346** EXPERIMENTAL 4347** 4348** ^The [xCreate] and [xConnect] methods of a 4349** [virtual table module] call this interface 4350** to declare the format (the names and datatypes of the columns) of 4351** the virtual tables they implement. 4352*/ 4353SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zSQL); 4354 4355/* 4356** CAPI3REF: Overload A Function For A Virtual Table 4357** EXPERIMENTAL 4358** 4359** ^(Virtual tables can provide alternative implementations of functions 4360** using the [xFindFunction] method of the [virtual table module]. 4361** But global versions of those functions 4362** must exist in order to be overloaded.)^ 4363** 4364** ^(This API makes sure a global version of a function with a particular 4365** name and number of parameters exists. If no such function exists 4366** before this API is called, a new function is created.)^ ^The implementation 4367** of the new function always causes an exception to be thrown. So 4368** the new function is not good for anything by itself. Its only 4369** purpose is to be a placeholder function that can be overloaded 4370** by a [virtual table]. 4371*/ 4372SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); 4373 4374/* 4375** The interface to the virtual-table mechanism defined above (back up 4376** to a comment remarkably similar to this one) is currently considered 4377** to be experimental. The interface might change in incompatible ways. 4378** If this is a problem for you, do not use the interface at this time. 4379** 4380** When the virtual-table mechanism stabilizes, we will declare the 4381** interface fixed, support it indefinitely, and remove this comment. 4382** 4383****** EXPERIMENTAL - subject to change without notice ************** 4384*/ 4385 4386/* 4387** CAPI3REF: A Handle To An Open BLOB 4388** KEYWORDS: {BLOB handle} {BLOB handles} 4389** 4390** An instance of this object represents an open BLOB on which 4391** [sqlite3_blob_open | incremental BLOB I/O] can be performed. 4392** ^Objects of this type are created by [sqlite3_blob_open()] 4393** and destroyed by [sqlite3_blob_close()]. 4394** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces 4395** can be used to read or write small subsections of the BLOB. 4396** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. 4397*/ 4398typedef struct sqlite3_blob sqlite3_blob; 4399 4400/* 4401** CAPI3REF: Open A BLOB For Incremental I/O 4402** 4403** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located 4404** in row iRow, column zColumn, table zTable in database zDb; 4405** in other words, the same BLOB that would be selected by: 4406** 4407** <pre> 4408** SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow; 4409** </pre>)^ 4410** 4411** ^If the flags parameter is non-zero, then the BLOB is opened for read 4412** and write access. ^If it is zero, the BLOB is opened for read access. 4413** ^It is not possible to open a column that is part of an index or primary 4414** key for writing. ^If [foreign key constraints] are enabled, it is 4415** not possible to open a column that is part of a [child key] for writing. 4416** 4417** ^Note that the database name is not the filename that contains 4418** the database but rather the symbolic name of the database that 4419** appears after the AS keyword when the database is connected using [ATTACH]. 4420** ^For the main database file, the database name is "main". 4421** ^For TEMP tables, the database name is "temp". 4422** 4423** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is written 4424** to *ppBlob. Otherwise an [error code] is returned and *ppBlob is set 4425** to be a null pointer.)^ 4426** ^This function sets the [database connection] error code and message 4427** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()] and related 4428** functions. ^Note that the *ppBlob variable is always initialized in a 4429** way that makes it safe to invoke [sqlite3_blob_close()] on *ppBlob 4430** regardless of the success or failure of this routine. 4431** 4432** ^(If the row that a BLOB handle points to is modified by an 4433** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects 4434** then the BLOB handle is marked as "expired". 4435** This is true if any column of the row is changed, even a column 4436** other than the one the BLOB handle is open on.)^ 4437** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for 4438** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. 4439** ^(Changes written into a BLOB prior to the BLOB expiring are not 4440** rolled back by the expiration of the BLOB. Such changes will eventually 4441** commit if the transaction continues to completion.)^ 4442** 4443** ^Use the [sqlite3_blob_bytes()] interface to determine the size of 4444** the opened blob. ^The size of a blob may not be changed by this 4445** interface. Use the [UPDATE] SQL command to change the size of a 4446** blob. 4447** 4448** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces 4449** and the built-in [zeroblob] SQL function can be used, if desired, 4450** to create an empty, zero-filled blob in which to read or write using 4451** this interface. 4452** 4453** To avoid a resource leak, every open [BLOB handle] should eventually 4454** be released by a call to [sqlite3_blob_close()]. 4455*/ 4456int sqlite3_blob_open( 4457 sqlite3*, 4458 const char *zDb, 4459 const char *zTable, 4460 const char *zColumn, 4461 sqlite3_int64 iRow, 4462 int flags, 4463 sqlite3_blob **ppBlob 4464); 4465 4466/* 4467** CAPI3REF: Close A BLOB Handle 4468** 4469** ^Closes an open [BLOB handle]. 4470** 4471** ^Closing a BLOB shall cause the current transaction to commit 4472** if there are no other BLOBs, no pending prepared statements, and the 4473** database connection is in [autocommit mode]. 4474** ^If any writes were made to the BLOB, they might be held in cache 4475** until the close operation if they will fit. 4476** 4477** ^(Closing the BLOB often forces the changes 4478** out to disk and so if any I/O errors occur, they will likely occur 4479** at the time when the BLOB is closed. Any errors that occur during 4480** closing are reported as a non-zero return value.)^ 4481** 4482** ^(The BLOB is closed unconditionally. Even if this routine returns 4483** an error code, the BLOB is still closed.)^ 4484** 4485** ^Calling this routine with a null pointer (such as would be returned 4486** by a failed call to [sqlite3_blob_open()]) is a harmless no-op. 4487*/ 4488int sqlite3_blob_close(sqlite3_blob *); 4489 4490/* 4491** CAPI3REF: Return The Size Of An Open BLOB 4492** 4493** ^Returns the size in bytes of the BLOB accessible via the 4494** successfully opened [BLOB handle] in its only argument. ^The 4495** incremental blob I/O routines can only read or overwriting existing 4496** blob content; they cannot change the size of a blob. 4497** 4498** This routine only works on a [BLOB handle] which has been created 4499** by a prior successful call to [sqlite3_blob_open()] and which has not 4500** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4501** to this routine results in undefined and probably undesirable behavior. 4502*/ 4503int sqlite3_blob_bytes(sqlite3_blob *); 4504 4505/* 4506** CAPI3REF: Read Data From A BLOB Incrementally 4507** 4508** ^(This function is used to read data from an open [BLOB handle] into a 4509** caller-supplied buffer. N bytes of data are copied into buffer Z 4510** from the open BLOB, starting at offset iOffset.)^ 4511** 4512** ^If offset iOffset is less than N bytes from the end of the BLOB, 4513** [SQLITE_ERROR] is returned and no data is read. ^If N or iOffset is 4514** less than zero, [SQLITE_ERROR] is returned and no data is read. 4515** ^The size of the blob (and hence the maximum value of N+iOffset) 4516** can be determined using the [sqlite3_blob_bytes()] interface. 4517** 4518** ^An attempt to read from an expired [BLOB handle] fails with an 4519** error code of [SQLITE_ABORT]. 4520** 4521** ^(On success, sqlite3_blob_read() returns SQLITE_OK. 4522** Otherwise, an [error code] or an [extended error code] is returned.)^ 4523** 4524** This routine only works on a [BLOB handle] which has been created 4525** by a prior successful call to [sqlite3_blob_open()] and which has not 4526** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4527** to this routine results in undefined and probably undesirable behavior. 4528** 4529** See also: [sqlite3_blob_write()]. 4530*/ 4531int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); 4532 4533/* 4534** CAPI3REF: Write Data Into A BLOB Incrementally 4535** 4536** ^This function is used to write data into an open [BLOB handle] from a 4537** caller-supplied buffer. ^N bytes of data are copied from the buffer Z 4538** into the open BLOB, starting at offset iOffset. 4539** 4540** ^If the [BLOB handle] passed as the first argument was not opened for 4541** writing (the flags parameter to [sqlite3_blob_open()] was zero), 4542** this function returns [SQLITE_READONLY]. 4543** 4544** ^This function may only modify the contents of the BLOB; it is 4545** not possible to increase the size of a BLOB using this API. 4546** ^If offset iOffset is less than N bytes from the end of the BLOB, 4547** [SQLITE_ERROR] is returned and no data is written. ^If N is 4548** less than zero [SQLITE_ERROR] is returned and no data is written. 4549** The size of the BLOB (and hence the maximum value of N+iOffset) 4550** can be determined using the [sqlite3_blob_bytes()] interface. 4551** 4552** ^An attempt to write to an expired [BLOB handle] fails with an 4553** error code of [SQLITE_ABORT]. ^Writes to the BLOB that occurred 4554** before the [BLOB handle] expired are not rolled back by the 4555** expiration of the handle, though of course those changes might 4556** have been overwritten by the statement that expired the BLOB handle 4557** or by other independent statements. 4558** 4559** ^(On success, sqlite3_blob_write() returns SQLITE_OK. 4560** Otherwise, an [error code] or an [extended error code] is returned.)^ 4561** 4562** This routine only works on a [BLOB handle] which has been created 4563** by a prior successful call to [sqlite3_blob_open()] and which has not 4564** been closed by [sqlite3_blob_close()]. Passing any other pointer in 4565** to this routine results in undefined and probably undesirable behavior. 4566** 4567** See also: [sqlite3_blob_read()]. 4568*/ 4569int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); 4570 4571/* 4572** CAPI3REF: Virtual File System Objects 4573** 4574** A virtual filesystem (VFS) is an [sqlite3_vfs] object 4575** that SQLite uses to interact 4576** with the underlying operating system. Most SQLite builds come with a 4577** single default VFS that is appropriate for the host computer. 4578** New VFSes can be registered and existing VFSes can be unregistered. 4579** The following interfaces are provided. 4580** 4581** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. 4582** ^Names are case sensitive. 4583** ^Names are zero-terminated UTF-8 strings. 4584** ^If there is no match, a NULL pointer is returned. 4585** ^If zVfsName is NULL then the default VFS is returned. 4586** 4587** ^New VFSes are registered with sqlite3_vfs_register(). 4588** ^Each new VFS becomes the default VFS if the makeDflt flag is set. 4589** ^The same VFS can be registered multiple times without injury. 4590** ^To make an existing VFS into the default VFS, register it again 4591** with the makeDflt flag set. If two different VFSes with the 4592** same name are registered, the behavior is undefined. If a 4593** VFS is registered with a name that is NULL or an empty string, 4594** then the behavior is undefined. 4595** 4596** ^Unregister a VFS with the sqlite3_vfs_unregister() interface. 4597** ^(If the default VFS is unregistered, another VFS is chosen as 4598** the default. The choice for the new VFS is arbitrary.)^ 4599*/ 4600sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); 4601int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); 4602int sqlite3_vfs_unregister(sqlite3_vfs*); 4603 4604/* 4605** CAPI3REF: Mutexes 4606** 4607** The SQLite core uses these routines for thread 4608** synchronization. Though they are intended for internal 4609** use by SQLite, code that links against SQLite is 4610** permitted to use any of these routines. 4611** 4612** The SQLite source code contains multiple implementations 4613** of these mutex routines. An appropriate implementation 4614** is selected automatically at compile-time. ^(The following 4615** implementations are available in the SQLite core: 4616** 4617** <ul> 4618** <li> SQLITE_MUTEX_OS2 4619** <li> SQLITE_MUTEX_PTHREAD 4620** <li> SQLITE_MUTEX_W32 4621** <li> SQLITE_MUTEX_NOOP 4622** </ul>)^ 4623** 4624** ^The SQLITE_MUTEX_NOOP implementation is a set of routines 4625** that does no real locking and is appropriate for use in 4626** a single-threaded application. ^The SQLITE_MUTEX_OS2, 4627** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations 4628** are appropriate for use on OS/2, Unix, and Windows. 4629** 4630** ^(If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor 4631** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex 4632** implementation is included with the library. In this case the 4633** application must supply a custom mutex implementation using the 4634** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function 4635** before calling sqlite3_initialize() or any other public sqlite3_ 4636** function that calls sqlite3_initialize().)^ 4637** 4638** ^The sqlite3_mutex_alloc() routine allocates a new 4639** mutex and returns a pointer to it. ^If it returns NULL 4640** that means that a mutex could not be allocated. ^SQLite 4641** will unwind its stack and return an error. ^(The argument 4642** to sqlite3_mutex_alloc() is one of these integer constants: 4643** 4644** <ul> 4645** <li> SQLITE_MUTEX_FAST 4646** <li> SQLITE_MUTEX_RECURSIVE 4647** <li> SQLITE_MUTEX_STATIC_MASTER 4648** <li> SQLITE_MUTEX_STATIC_MEM 4649** <li> SQLITE_MUTEX_STATIC_MEM2 4650** <li> SQLITE_MUTEX_STATIC_PRNG 4651** <li> SQLITE_MUTEX_STATIC_LRU 4652** <li> SQLITE_MUTEX_STATIC_LRU2 4653** </ul>)^ 4654** 4655** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) 4656** cause sqlite3_mutex_alloc() to create 4657** a new mutex. ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE 4658** is used but not necessarily so when SQLITE_MUTEX_FAST is used. 4659** The mutex implementation does not need to make a distinction 4660** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does 4661** not want to. ^SQLite will only request a recursive mutex in 4662** cases where it really needs one. ^If a faster non-recursive mutex 4663** implementation is available on the host platform, the mutex subsystem 4664** might return such a mutex in response to SQLITE_MUTEX_FAST. 4665** 4666** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other 4667** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return 4668** a pointer to a static preexisting mutex. ^Six static mutexes are 4669** used by the current version of SQLite. Future versions of SQLite 4670** may add additional static mutexes. Static mutexes are for internal 4671** use by SQLite only. Applications that use SQLite mutexes should 4672** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or 4673** SQLITE_MUTEX_RECURSIVE. 4674** 4675** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST 4676** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() 4677** returns a different mutex on every call. ^But for the static 4678** mutex types, the same mutex is returned on every call that has 4679** the same type number. 4680** 4681** ^The sqlite3_mutex_free() routine deallocates a previously 4682** allocated dynamic mutex. ^SQLite is careful to deallocate every 4683** dynamic mutex that it allocates. The dynamic mutexes must not be in 4684** use when they are deallocated. Attempting to deallocate a static 4685** mutex results in undefined behavior. ^SQLite never deallocates 4686** a static mutex. 4687** 4688** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt 4689** to enter a mutex. ^If another thread is already within the mutex, 4690** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return 4691** SQLITE_BUSY. ^The sqlite3_mutex_try() interface returns [SQLITE_OK] 4692** upon successful entry. ^(Mutexes created using 4693** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. 4694** In such cases the, 4695** mutex must be exited an equal number of times before another thread 4696** can enter.)^ ^(If the same thread tries to enter any other 4697** kind of mutex more than once, the behavior is undefined. 4698** SQLite will never exhibit 4699** such behavior in its own use of mutexes.)^ 4700** 4701** ^(Some systems (for example, Windows 95) do not support the operation 4702** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() 4703** will always return SQLITE_BUSY. The SQLite core only ever uses 4704** sqlite3_mutex_try() as an optimization so this is acceptable behavior.)^ 4705** 4706** ^The sqlite3_mutex_leave() routine exits a mutex that was 4707** previously entered by the same thread. ^(The behavior 4708** is undefined if the mutex is not currently entered by the 4709** calling thread or is not currently allocated. SQLite will 4710** never do either.)^ 4711** 4712** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or 4713** sqlite3_mutex_leave() is a NULL pointer, then all three routines 4714** behave as no-ops. 4715** 4716** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. 4717*/ 4718sqlite3_mutex *sqlite3_mutex_alloc(int); 4719void sqlite3_mutex_free(sqlite3_mutex*); 4720void sqlite3_mutex_enter(sqlite3_mutex*); 4721int sqlite3_mutex_try(sqlite3_mutex*); 4722void sqlite3_mutex_leave(sqlite3_mutex*); 4723 4724/* 4725** CAPI3REF: Mutex Methods Object 4726** EXPERIMENTAL 4727** 4728** An instance of this structure defines the low-level routines 4729** used to allocate and use mutexes. 4730** 4731** Usually, the default mutex implementations provided by SQLite are 4732** sufficient, however the user has the option of substituting a custom 4733** implementation for specialized deployments or systems for which SQLite 4734** does not provide a suitable implementation. In this case, the user 4735** creates and populates an instance of this structure to pass 4736** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. 4737** Additionally, an instance of this structure can be used as an 4738** output variable when querying the system for the current mutex 4739** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. 4740** 4741** ^The xMutexInit method defined by this structure is invoked as 4742** part of system initialization by the sqlite3_initialize() function. 4743** ^The xMutexInit routine is calle by SQLite exactly once for each 4744** effective call to [sqlite3_initialize()]. 4745** 4746** ^The xMutexEnd method defined by this structure is invoked as 4747** part of system shutdown by the sqlite3_shutdown() function. The 4748** implementation of this method is expected to release all outstanding 4749** resources obtained by the mutex methods implementation, especially 4750** those obtained by the xMutexInit method. ^The xMutexEnd() 4751** interface is invoked exactly once for each call to [sqlite3_shutdown()]. 4752** 4753** ^(The remaining seven methods defined by this structure (xMutexAlloc, 4754** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and 4755** xMutexNotheld) implement the following interfaces (respectively): 4756** 4757** <ul> 4758** <li> [sqlite3_mutex_alloc()] </li> 4759** <li> [sqlite3_mutex_free()] </li> 4760** <li> [sqlite3_mutex_enter()] </li> 4761** <li> [sqlite3_mutex_try()] </li> 4762** <li> [sqlite3_mutex_leave()] </li> 4763** <li> [sqlite3_mutex_held()] </li> 4764** <li> [sqlite3_mutex_notheld()] </li> 4765** </ul>)^ 4766** 4767** The only difference is that the public sqlite3_XXX functions enumerated 4768** above silently ignore any invocations that pass a NULL pointer instead 4769** of a valid mutex handle. The implementations of the methods defined 4770** by this structure are not required to handle this case, the results 4771** of passing a NULL pointer instead of a valid mutex handle are undefined 4772** (i.e. it is acceptable to provide an implementation that segfaults if 4773** it is passed a NULL pointer). 4774** 4775** The xMutexInit() method must be threadsafe. ^It must be harmless to 4776** invoke xMutexInit() mutiple times within the same process and without 4777** intervening calls to xMutexEnd(). Second and subsequent calls to 4778** xMutexInit() must be no-ops. 4779** 4780** ^xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()] 4781** and its associates). ^Similarly, xMutexAlloc() must not use SQLite memory 4782** allocation for a static mutex. ^However xMutexAlloc() may use SQLite 4783** memory allocation for a fast or recursive mutex. 4784** 4785** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is 4786** called, but only if the prior call to xMutexInit returned SQLITE_OK. 4787** If xMutexInit fails in any way, it is expected to clean up after itself 4788** prior to returning. 4789*/ 4790typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; 4791struct sqlite3_mutex_methods { 4792 int (*xMutexInit)(void); 4793 int (*xMutexEnd)(void); 4794 sqlite3_mutex *(*xMutexAlloc)(int); 4795 void (*xMutexFree)(sqlite3_mutex *); 4796 void (*xMutexEnter)(sqlite3_mutex *); 4797 int (*xMutexTry)(sqlite3_mutex *); 4798 void (*xMutexLeave)(sqlite3_mutex *); 4799 int (*xMutexHeld)(sqlite3_mutex *); 4800 int (*xMutexNotheld)(sqlite3_mutex *); 4801}; 4802 4803/* 4804** CAPI3REF: Mutex Verification Routines 4805** 4806** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines 4807** are intended for use inside assert() statements. ^The SQLite core 4808** never uses these routines except inside an assert() and applications 4809** are advised to follow the lead of the core. ^The SQLite core only 4810** provides implementations for these routines when it is compiled 4811** with the SQLITE_DEBUG flag. ^External mutex implementations 4812** are only required to provide these routines if SQLITE_DEBUG is 4813** defined and if NDEBUG is not defined. 4814** 4815** ^These routines should return true if the mutex in their argument 4816** is held or not held, respectively, by the calling thread. 4817** 4818** ^The implementation is not required to provided versions of these 4819** routines that actually work. If the implementation does not provide working 4820** versions of these routines, it should at least provide stubs that always 4821** return true so that one does not get spurious assertion failures. 4822** 4823** ^If the argument to sqlite3_mutex_held() is a NULL pointer then 4824** the routine should return 1. This seems counter-intuitive since 4825** clearly the mutex cannot be held if it does not exist. But the 4826** the reason the mutex does not exist is because the build is not 4827** using mutexes. And we do not want the assert() containing the 4828** call to sqlite3_mutex_held() to fail, so a non-zero return is 4829** the appropriate thing to do. ^The sqlite3_mutex_notheld() 4830** interface should also return 1 when given a NULL pointer. 4831*/ 4832#ifndef NDEBUG 4833int sqlite3_mutex_held(sqlite3_mutex*); 4834int sqlite3_mutex_notheld(sqlite3_mutex*); 4835#endif 4836 4837/* 4838** CAPI3REF: Mutex Types 4839** 4840** The [sqlite3_mutex_alloc()] interface takes a single argument 4841** which is one of these integer constants. 4842** 4843** The set of static mutexes may change from one SQLite release to the 4844** next. Applications that override the built-in mutex logic must be 4845** prepared to accommodate additional static mutexes. 4846*/ 4847#define SQLITE_MUTEX_FAST 0 4848#define SQLITE_MUTEX_RECURSIVE 1 4849#define SQLITE_MUTEX_STATIC_MASTER 2 4850#define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ 4851#define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ 4852#define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ 4853#define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ 4854#define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ 4855#define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ 4856 4857/* 4858** CAPI3REF: Retrieve the mutex for a database connection 4859** 4860** ^This interface returns a pointer the [sqlite3_mutex] object that 4861** serializes access to the [database connection] given in the argument 4862** when the [threading mode] is Serialized. 4863** ^If the [threading mode] is Single-thread or Multi-thread then this 4864** routine returns a NULL pointer. 4865*/ 4866sqlite3_mutex *sqlite3_db_mutex(sqlite3*); 4867 4868/* 4869** CAPI3REF: Low-Level Control Of Database Files 4870** 4871** ^The [sqlite3_file_control()] interface makes a direct call to the 4872** xFileControl method for the [sqlite3_io_methods] object associated 4873** with a particular database identified by the second argument. ^The 4874** name of the database "main" for the main database or "temp" for the 4875** TEMP database, or the name that appears after the AS keyword for 4876** databases that are added using the [ATTACH] SQL command. 4877** ^A NULL pointer can be used in place of "main" to refer to the 4878** main database file. 4879** ^The third and fourth parameters to this routine 4880** are passed directly through to the second and third parameters of 4881** the xFileControl method. ^The return value of the xFileControl 4882** method becomes the return value of this routine. 4883** 4884** ^If the second parameter (zDbName) does not match the name of any 4885** open database file, then SQLITE_ERROR is returned. ^This error 4886** code is not remembered and will not be recalled by [sqlite3_errcode()] 4887** or [sqlite3_errmsg()]. The underlying xFileControl method might 4888** also return SQLITE_ERROR. There is no way to distinguish between 4889** an incorrect zDbName and an SQLITE_ERROR return from the underlying 4890** xFileControl method. 4891** 4892** See also: [SQLITE_FCNTL_LOCKSTATE] 4893*/ 4894int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); 4895 4896/* 4897** CAPI3REF: Testing Interface 4898** 4899** ^The sqlite3_test_control() interface is used to read out internal 4900** state of SQLite and to inject faults into SQLite for testing 4901** purposes. ^The first parameter is an operation code that determines 4902** the number, meaning, and operation of all subsequent parameters. 4903** 4904** This interface is not for use by applications. It exists solely 4905** for verifying the correct operation of the SQLite library. Depending 4906** on how the SQLite library is compiled, this interface might not exist. 4907** 4908** The details of the operation codes, their meanings, the parameters 4909** they take, and what they do are all subject to change without notice. 4910** Unlike most of the SQLite API, this function is not guaranteed to 4911** operate consistently from one release to the next. 4912*/ 4913int sqlite3_test_control(int op, ...); 4914 4915/* 4916** CAPI3REF: Testing Interface Operation Codes 4917** 4918** These constants are the valid operation code parameters used 4919** as the first argument to [sqlite3_test_control()]. 4920** 4921** These parameters and their meanings are subject to change 4922** without notice. These values are for testing purposes only. 4923** Applications should not use any of these parameters or the 4924** [sqlite3_test_control()] interface. 4925*/ 4926#define SQLITE_TESTCTRL_PRNG_SAVE 5 4927#define SQLITE_TESTCTRL_PRNG_RESTORE 6 4928#define SQLITE_TESTCTRL_PRNG_RESET 7 4929#define SQLITE_TESTCTRL_BITVEC_TEST 8 4930#define SQLITE_TESTCTRL_FAULT_INSTALL 9 4931#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 4932#define SQLITE_TESTCTRL_PENDING_BYTE 11 4933#define SQLITE_TESTCTRL_ASSERT 12 4934#define SQLITE_TESTCTRL_ALWAYS 13 4935#define SQLITE_TESTCTRL_RESERVE 14 4936 4937/* 4938** CAPI3REF: SQLite Runtime Status 4939** EXPERIMENTAL 4940** 4941** ^This interface is used to retrieve runtime status information 4942** about the preformance of SQLite, and optionally to reset various 4943** highwater marks. ^The first argument is an integer code for 4944** the specific parameter to measure. ^(Recognized integer codes 4945** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...].)^ 4946** ^The current value of the parameter is returned into *pCurrent. 4947** ^The highest recorded value is returned in *pHighwater. ^If the 4948** resetFlag is true, then the highest record value is reset after 4949** *pHighwater is written. ^(Some parameters do not record the highest 4950** value. For those parameters 4951** nothing is written into *pHighwater and the resetFlag is ignored.)^ 4952** ^(Other parameters record only the highwater mark and not the current 4953** value. For these latter parameters nothing is written into *pCurrent.)^ 4954** 4955** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a 4956** non-zero [error code] on failure. 4957** 4958** This routine is threadsafe but is not atomic. This routine can be 4959** called while other threads are running the same or different SQLite 4960** interfaces. However the values returned in *pCurrent and 4961** *pHighwater reflect the status of SQLite at different points in time 4962** and it is possible that another thread might change the parameter 4963** in between the times when *pCurrent and *pHighwater are written. 4964** 4965** See also: [sqlite3_db_status()] 4966*/ 4967SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); 4968 4969 4970/* 4971** CAPI3REF: Status Parameters 4972** EXPERIMENTAL 4973** 4974** These integer constants designate various run-time status parameters 4975** that can be returned by [sqlite3_status()]. 4976** 4977** <dl> 4978** ^(<dt>SQLITE_STATUS_MEMORY_USED</dt> 4979** <dd>This parameter is the current amount of memory checked out 4980** using [sqlite3_malloc()], either directly or indirectly. The 4981** figure includes calls made to [sqlite3_malloc()] by the application 4982** and internal memory usage by the SQLite library. Scratch memory 4983** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache 4984** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in 4985** this parameter. The amount returned is the sum of the allocation 4986** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^ 4987** 4988** ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt> 4989** <dd>This parameter records the largest memory allocation request 4990** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their 4991** internal equivalents). Only the value returned in the 4992** *pHighwater parameter to [sqlite3_status()] is of interest. 4993** The value written into the *pCurrent parameter is undefined.</dd>)^ 4994** 4995** ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt> 4996** <dd>This parameter returns the number of pages used out of the 4997** [pagecache memory allocator] that was configured using 4998** [SQLITE_CONFIG_PAGECACHE]. The 4999** value returned is in pages, not in bytes.</dd>)^ 5000** 5001** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt> 5002** <dd>This parameter returns the number of bytes of page cache 5003** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] 5004** buffer and where forced to overflow to [sqlite3_malloc()]. The 5005** returned value includes allocations that overflowed because they 5006** where too large (they were larger than the "sz" parameter to 5007** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because 5008** no space was left in the page cache.</dd>)^ 5009** 5010** ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt> 5011** <dd>This parameter records the largest memory allocation request 5012** handed to [pagecache memory allocator]. Only the value returned in the 5013** *pHighwater parameter to [sqlite3_status()] is of interest. 5014** The value written into the *pCurrent parameter is undefined.</dd>)^ 5015** 5016** ^(<dt>SQLITE_STATUS_SCRATCH_USED</dt> 5017** <dd>This parameter returns the number of allocations used out of the 5018** [scratch memory allocator] configured using 5019** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not 5020** in bytes. Since a single thread may only have one scratch allocation 5021** outstanding at time, this parameter also reports the number of threads 5022** using scratch memory at the same time.</dd>)^ 5023** 5024** ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt> 5025** <dd>This parameter returns the number of bytes of scratch memory 5026** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] 5027** buffer and where forced to overflow to [sqlite3_malloc()]. The values 5028** returned include overflows because the requested allocation was too 5029** larger (that is, because the requested allocation was larger than the 5030** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer 5031** slots were available. 5032** </dd>)^ 5033** 5034** ^(<dt>SQLITE_STATUS_SCRATCH_SIZE</dt> 5035** <dd>This parameter records the largest memory allocation request 5036** handed to [scratch memory allocator]. Only the value returned in the 5037** *pHighwater parameter to [sqlite3_status()] is of interest. 5038** The value written into the *pCurrent parameter is undefined.</dd>)^ 5039** 5040** ^(<dt>SQLITE_STATUS_PARSER_STACK</dt> 5041** <dd>This parameter records the deepest parser stack. It is only 5042** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^ 5043** </dl> 5044** 5045** New status parameters may be added from time to time. 5046*/ 5047#define SQLITE_STATUS_MEMORY_USED 0 5048#define SQLITE_STATUS_PAGECACHE_USED 1 5049#define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 5050#define SQLITE_STATUS_SCRATCH_USED 3 5051#define SQLITE_STATUS_SCRATCH_OVERFLOW 4 5052#define SQLITE_STATUS_MALLOC_SIZE 5 5053#define SQLITE_STATUS_PARSER_STACK 6 5054#define SQLITE_STATUS_PAGECACHE_SIZE 7 5055#define SQLITE_STATUS_SCRATCH_SIZE 8 5056 5057/* 5058** CAPI3REF: Database Connection Status 5059** EXPERIMENTAL 5060** 5061** ^This interface is used to retrieve runtime status information 5062** about a single [database connection]. ^The first argument is the 5063** database connection object to be interrogated. ^The second argument 5064** is the parameter to interrogate. ^Currently, the only allowed value 5065** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. 5066** Additional options will likely appear in future releases of SQLite. 5067** 5068** ^The current value of the requested parameter is written into *pCur 5069** and the highest instantaneous value is written into *pHiwtr. ^If 5070** the resetFlg is true, then the highest instantaneous value is 5071** reset back down to the current value. 5072** 5073** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. 5074*/ 5075SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); 5076 5077/* 5078** CAPI3REF: Status Parameters for database connections 5079** EXPERIMENTAL 5080** 5081** These constants are the available integer "verbs" that can be passed as 5082** the second argument to the [sqlite3_db_status()] interface. 5083** 5084** New verbs may be added in future releases of SQLite. Existing verbs 5085** might be discontinued. Applications should check the return code from 5086** [sqlite3_db_status()] to make sure that the call worked. 5087** The [sqlite3_db_status()] interface will return a non-zero error code 5088** if a discontinued or unsupported verb is invoked. 5089** 5090** <dl> 5091** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt> 5092** <dd>This parameter returns the number of lookaside memory slots currently 5093** checked out.</dd>)^ 5094** </dl> 5095*/ 5096#define SQLITE_DBSTATUS_LOOKASIDE_USED 0 5097 5098 5099/* 5100** CAPI3REF: Prepared Statement Status 5101** EXPERIMENTAL 5102** 5103** ^(Each prepared statement maintains various 5104** [SQLITE_STMTSTATUS_SORT | counters] that measure the number 5105** of times it has performed specific operations.)^ These counters can 5106** be used to monitor the performance characteristics of the prepared 5107** statements. For example, if the number of table steps greatly exceeds 5108** the number of table searches or result rows, that would tend to indicate 5109** that the prepared statement is using a full table scan rather than 5110** an index. 5111** 5112** ^(This interface is used to retrieve and reset counter values from 5113** a [prepared statement]. The first argument is the prepared statement 5114** object to be interrogated. The second argument 5115** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] 5116** to be interrogated.)^ 5117** ^The current value of the requested counter is returned. 5118** ^If the resetFlg is true, then the counter is reset to zero after this 5119** interface call returns. 5120** 5121** See also: [sqlite3_status()] and [sqlite3_db_status()]. 5122*/ 5123SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); 5124 5125/* 5126** CAPI3REF: Status Parameters for prepared statements 5127** EXPERIMENTAL 5128** 5129** These preprocessor macros define integer codes that name counter 5130** values associated with the [sqlite3_stmt_status()] interface. 5131** The meanings of the various counters are as follows: 5132** 5133** <dl> 5134** <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt> 5135** <dd>^This is the number of times that SQLite has stepped forward in 5136** a table as part of a full table scan. Large numbers for this counter 5137** may indicate opportunities for performance improvement through 5138** careful use of indices.</dd> 5139** 5140** <dt>SQLITE_STMTSTATUS_SORT</dt> 5141** <dd>^This is the number of sort operations that have occurred. 5142** A non-zero value in this counter may indicate an opportunity to 5143** improvement performance through careful use of indices.</dd> 5144** 5145** </dl> 5146*/ 5147#define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 5148#define SQLITE_STMTSTATUS_SORT 2 5149 5150/* 5151** CAPI3REF: Custom Page Cache Object 5152** EXPERIMENTAL 5153** 5154** The sqlite3_pcache type is opaque. It is implemented by 5155** the pluggable module. The SQLite core has no knowledge of 5156** its size or internal structure and never deals with the 5157** sqlite3_pcache object except by holding and passing pointers 5158** to the object. 5159** 5160** See [sqlite3_pcache_methods] for additional information. 5161*/ 5162typedef struct sqlite3_pcache sqlite3_pcache; 5163 5164/* 5165** CAPI3REF: Application Defined Page Cache. 5166** KEYWORDS: {page cache} 5167** EXPERIMENTAL 5168** 5169** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can 5170** register an alternative page cache implementation by passing in an 5171** instance of the sqlite3_pcache_methods structure.)^ The majority of the 5172** heap memory used by SQLite is used by the page cache to cache data read 5173** from, or ready to be written to, the database file. By implementing a 5174** custom page cache using this API, an application can control more 5175** precisely the amount of memory consumed by SQLite, the way in which 5176** that memory is allocated and released, and the policies used to 5177** determine exactly which parts of a database file are cached and for 5178** how long. 5179** 5180** ^(The contents of the sqlite3_pcache_methods structure are copied to an 5181** internal buffer by SQLite within the call to [sqlite3_config]. Hence 5182** the application may discard the parameter after the call to 5183** [sqlite3_config()] returns.)^ 5184** 5185** ^The xInit() method is called once for each call to [sqlite3_initialize()] 5186** (usually only once during the lifetime of the process). ^(The xInit() 5187** method is passed a copy of the sqlite3_pcache_methods.pArg value.)^ 5188** ^The xInit() method can set up up global structures and/or any mutexes 5189** required by the custom page cache implementation. 5190** 5191** ^The xShutdown() method is called from within [sqlite3_shutdown()], 5192** if the application invokes this API. It can be used to clean up 5193** any outstanding resources before process shutdown, if required. 5194** 5195** ^SQLite holds a [SQLITE_MUTEX_RECURSIVE] mutex when it invokes 5196** the xInit method, so the xInit method need not be threadsafe. ^The 5197** xShutdown method is only called from [sqlite3_shutdown()] so it does 5198** not need to be threadsafe either. All other methods must be threadsafe 5199** in multithreaded applications. 5200** 5201** ^SQLite will never invoke xInit() more than once without an intervening 5202** call to xShutdown(). 5203** 5204** ^The xCreate() method is used to construct a new cache instance. SQLite 5205** will typically create one cache instance for each open database file, 5206** though this is not guaranteed. ^The 5207** first parameter, szPage, is the size in bytes of the pages that must 5208** be allocated by the cache. ^szPage will not be a power of two. ^szPage 5209** will the page size of the database file that is to be cached plus an 5210** increment (here called "R") of about 100 or 200. ^SQLite will use the 5211** extra R bytes on each page to store metadata about the underlying 5212** database page on disk. The value of R depends 5213** on the SQLite version, the target platform, and how SQLite was compiled. 5214** ^R is constant for a particular build of SQLite. ^The second argument to 5215** xCreate(), bPurgeable, is true if the cache being created will 5216** be used to cache database pages of a file stored on disk, or 5217** false if it is used for an in-memory database. ^The cache implementation 5218** does not have to do anything special based with the value of bPurgeable; 5219** it is purely advisory. ^On a cache where bPurgeable is false, SQLite will 5220** never invoke xUnpin() except to deliberately delete a page. 5221** ^In other words, a cache created with bPurgeable set to false will 5222** never contain any unpinned pages. 5223** 5224** ^(The xCachesize() method may be called at any time by SQLite to set the 5225** suggested maximum cache-size (number of pages stored by) the cache 5226** instance passed as the first argument. This is the value configured using 5227** the SQLite "[PRAGMA cache_size]" command.)^ ^As with the bPurgeable 5228** parameter, the implementation is not required to do anything with this 5229** value; it is advisory only. 5230** 5231** ^The xPagecount() method should return the number of pages currently 5232** stored in the cache. 5233** 5234** ^The xFetch() method is used to fetch a page and return a pointer to it. 5235** ^A 'page', in this context, is a buffer of szPage bytes aligned at an 5236** 8-byte boundary. ^The page to be fetched is determined by the key. ^The 5237** mimimum key value is 1. After it has been retrieved using xFetch, the page 5238** is considered to be "pinned". 5239** 5240** ^If the requested page is already in the page cache, then the page cache 5241** implementation must return a pointer to the page buffer with its content 5242** intact. ^(If the requested page is not already in the cache, then the 5243** behavior of the cache implementation is determined by the value of the 5244** createFlag parameter passed to xFetch, according to the following table: 5245** 5246** <table border=1 width=85% align=center> 5247** <tr><th> createFlag <th> Behaviour when page is not already in cache 5248** <tr><td> 0 <td> Do not allocate a new page. Return NULL. 5249** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so. 5250** Otherwise return NULL. 5251** <tr><td> 2 <td> Make every effort to allocate a new page. Only return 5252** NULL if allocating a new page is effectively impossible. 5253** </table>)^ 5254** 5255** SQLite will normally invoke xFetch() with a createFlag of 0 or 1. If 5256** a call to xFetch() with createFlag==1 returns NULL, then SQLite will 5257** attempt to unpin one or more cache pages by spilling the content of 5258** pinned pages to disk and synching the operating system disk cache. After 5259** attempting to unpin pages, the xFetch() method will be invoked again with 5260** a createFlag of 2. 5261** 5262** ^xUnpin() is called by SQLite with a pointer to a currently pinned page 5263** as its second argument. ^(If the third parameter, discard, is non-zero, 5264** then the page should be evicted from the cache. In this case SQLite 5265** assumes that the next time the page is retrieved from the cache using 5266** the xFetch() method, it will be zeroed.)^ ^If the discard parameter is 5267** zero, then the page is considered to be unpinned. ^The cache implementation 5268** may choose to evict unpinned pages at any time. 5269** 5270** ^(The cache is not required to perform any reference counting. A single 5271** call to xUnpin() unpins the page regardless of the number of prior calls 5272** to xFetch().)^ 5273** 5274** ^The xRekey() method is used to change the key value associated with the 5275** page passed as the second argument from oldKey to newKey. ^If the cache 5276** previously contains an entry associated with newKey, it should be 5277** discarded. ^Any prior cache entry associated with newKey is guaranteed not 5278** to be pinned. 5279** 5280** ^When SQLite calls the xTruncate() method, the cache must discard all 5281** existing cache entries with page numbers (keys) greater than or equal 5282** to the value of the iLimit parameter passed to xTruncate(). ^If any 5283** of these pages are pinned, they are implicitly unpinned, meaning that 5284** they can be safely discarded. 5285** 5286** ^The xDestroy() method is used to delete a cache allocated by xCreate(). 5287** All resources associated with the specified cache should be freed. ^After 5288** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] 5289** handle invalid, and will not use it with any other sqlite3_pcache_methods 5290** functions. 5291*/ 5292typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; 5293struct sqlite3_pcache_methods { 5294 void *pArg; 5295 int (*xInit)(void*); 5296 void (*xShutdown)(void*); 5297 sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); 5298 void (*xCachesize)(sqlite3_pcache*, int nCachesize); 5299 int (*xPagecount)(sqlite3_pcache*); 5300 void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); 5301 void (*xUnpin)(sqlite3_pcache*, void*, int discard); 5302 void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); 5303 void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); 5304 void (*xDestroy)(sqlite3_pcache*); 5305}; 5306 5307/* 5308** CAPI3REF: Online Backup Object 5309** EXPERIMENTAL 5310** 5311** The sqlite3_backup object records state information about an ongoing 5312** online backup operation. ^The sqlite3_backup object is created by 5313** a call to [sqlite3_backup_init()] and is destroyed by a call to 5314** [sqlite3_backup_finish()]. 5315** 5316** See Also: [Using the SQLite Online Backup API] 5317*/ 5318typedef struct sqlite3_backup sqlite3_backup; 5319 5320/* 5321** CAPI3REF: Online Backup API. 5322** EXPERIMENTAL 5323** 5324** The backup API copies the content of one database into another. 5325** It is useful either for creating backups of databases or 5326** for copying in-memory databases to or from persistent files. 5327** 5328** See Also: [Using the SQLite Online Backup API] 5329** 5330** ^Exclusive access is required to the destination database for the 5331** duration of the operation. ^However the source database is only 5332** read-locked while it is actually being read; it is not locked 5333** continuously for the entire backup operation. ^Thus, the backup may be 5334** performed on a live source database without preventing other users from 5335** reading or writing to the source database while the backup is underway. 5336** 5337** ^(To perform a backup operation: 5338** <ol> 5339** <li><b>sqlite3_backup_init()</b> is called once to initialize the 5340** backup, 5341** <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 5342** the data between the two databases, and finally 5343** <li><b>sqlite3_backup_finish()</b> is called to release all resources 5344** associated with the backup operation. 5345** </ol>)^ 5346** There should be exactly one call to sqlite3_backup_finish() for each 5347** successful call to sqlite3_backup_init(). 5348** 5349** <b>sqlite3_backup_init()</b> 5350** 5351** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 5352** [database connection] associated with the destination database 5353** and the database name, respectively. 5354** ^The database name is "main" for the main database, "temp" for the 5355** temporary database, or the name specified after the AS keyword in 5356** an [ATTACH] statement for an attached database. 5357** ^The S and M arguments passed to 5358** sqlite3_backup_init(D,N,S,M) identify the [database connection] 5359** and database name of the source database, respectively. 5360** ^The source and destination [database connections] (parameters S and D) 5361** must be different or else sqlite3_backup_init(D,N,S,M) will file with 5362** an error. 5363** 5364** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is 5365** returned and an error code and error message are store3d in the 5366** destination [database connection] D. 5367** ^The error code and message for the failed call to sqlite3_backup_init() 5368** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or 5369** [sqlite3_errmsg16()] functions. 5370** ^A successful call to sqlite3_backup_init() returns a pointer to an 5371** [sqlite3_backup] object. 5372** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and 5373** sqlite3_backup_finish() functions to perform the specified backup 5374** operation. 5375** 5376** <b>sqlite3_backup_step()</b> 5377** 5378** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 5379** the source and destination databases specified by [sqlite3_backup] object B. 5380** ^If N is negative, all remaining source pages are copied. 5381** ^If sqlite3_backup_step(B,N) successfully copies N pages and there 5382** are still more pages to be copied, then the function resturns [SQLITE_OK]. 5383** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages 5384** from source to destination, then it returns [SQLITE_DONE]. 5385** ^If an error occurs while running sqlite3_backup_step(B,N), 5386** then an [error code] is returned. ^As well as [SQLITE_OK] and 5387** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], 5388** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an 5389** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. 5390** 5391** ^The sqlite3_backup_step() might return [SQLITE_READONLY] if the destination 5392** database was opened read-only or if 5393** the destination is an in-memory database with a different page size 5394** from the source database. 5395** 5396** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then 5397** the [sqlite3_busy_handler | busy-handler function] 5398** is invoked (if one is specified). ^If the 5399** busy-handler returns non-zero before the lock is available, then 5400** [SQLITE_BUSY] is returned to the caller. ^In this case the call to 5401** sqlite3_backup_step() can be retried later. ^If the source 5402** [database connection] 5403** is being used to write to the source database when sqlite3_backup_step() 5404** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this 5405** case the call to sqlite3_backup_step() can be retried later on. ^(If 5406** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or 5407** [SQLITE_READONLY] is returned, then 5408** there is no point in retrying the call to sqlite3_backup_step(). These 5409** errors are considered fatal.)^ The application must accept 5410** that the backup operation has failed and pass the backup operation handle 5411** to the sqlite3_backup_finish() to release associated resources. 5412** 5413** ^The first call to sqlite3_backup_step() obtains an exclusive lock 5414** on the destination file. ^The exclusive lock is not released until either 5415** sqlite3_backup_finish() is called or the backup operation is complete 5416** and sqlite3_backup_step() returns [SQLITE_DONE]. ^Every call to 5417** sqlite3_backup_step() obtains a [shared lock] on the source database that 5418** lasts for the duration of the sqlite3_backup_step() call. 5419** ^Because the source database is not locked between calls to 5420** sqlite3_backup_step(), the source database may be modified mid-way 5421** through the backup process. ^If the source database is modified by an 5422** external process or via a database connection other than the one being 5423** used by the backup operation, then the backup will be automatically 5424** restarted by the next call to sqlite3_backup_step(). ^If the source 5425** database is modified by the using the same database connection as is used 5426** by the backup operation, then the backup database is automatically 5427** updated at the same time. 5428** 5429** <b>sqlite3_backup_finish()</b> 5430** 5431** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 5432** application wishes to abandon the backup operation, the application 5433** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish(). 5434** ^The sqlite3_backup_finish() interfaces releases all 5435** resources associated with the [sqlite3_backup] object. 5436** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any 5437** active write-transaction on the destination database is rolled back. 5438** The [sqlite3_backup] object is invalid 5439** and may not be used following a call to sqlite3_backup_finish(). 5440** 5441** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no 5442** sqlite3_backup_step() errors occurred, regardless or whether or not 5443** sqlite3_backup_step() completed. 5444** ^If an out-of-memory condition or IO error occurred during any prior 5445** sqlite3_backup_step() call on the same [sqlite3_backup] object, then 5446** sqlite3_backup_finish() returns the corresponding [error code]. 5447** 5448** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() 5449** is not a permanent error and does not affect the return value of 5450** sqlite3_backup_finish(). 5451** 5452** <b>sqlite3_backup_remaining(), sqlite3_backup_pagecount()</b> 5453** 5454** ^Each call to sqlite3_backup_step() sets two values inside 5455** the [sqlite3_backup] object: the number of pages still to be backed 5456** up and the total number of pages in the source databae file. 5457** The sqlite3_backup_remaining() and sqlite3_backup_pagecount() interfaces 5458** retrieve these two values, respectively. 5459** 5460** ^The values returned by these functions are only updated by 5461** sqlite3_backup_step(). ^If the source database is modified during a backup 5462** operation, then the values are not updated to account for any extra 5463** pages that need to be updated or the size of the source database file 5464** changing. 5465** 5466** <b>Concurrent Usage of Database Handles</b> 5467** 5468** ^The source [database connection] may be used by the application for other 5469** purposes while a backup operation is underway or being initialized. 5470** ^If SQLite is compiled and configured to support threadsafe database 5471** connections, then the source database connection may be used concurrently 5472** from within other threads. 5473** 5474** However, the application must guarantee that the destination 5475** [database connection] is not passed to any other API (by any thread) after 5476** sqlite3_backup_init() is called and before the corresponding call to 5477** sqlite3_backup_finish(). SQLite does not currently check to see 5478** if the application incorrectly accesses the destination [database connection] 5479** and so no error code is reported, but the operations may malfunction 5480** nevertheless. Use of the destination database connection while a 5481** backup is in progress might also also cause a mutex deadlock. 5482** 5483** If running in [shared cache mode], the application must 5484** guarantee that the shared cache used by the destination database 5485** is not accessed while the backup is running. In practice this means 5486** that the application must guarantee that the disk file being 5487** backed up to is not accessed by any connection within the process, 5488** not just the specific connection that was passed to sqlite3_backup_init(). 5489** 5490** The [sqlite3_backup] object itself is partially threadsafe. Multiple 5491** threads may safely make multiple concurrent calls to sqlite3_backup_step(). 5492** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() 5493** APIs are not strictly speaking threadsafe. If they are invoked at the 5494** same time as another thread is invoking sqlite3_backup_step() it is 5495** possible that they return invalid values. 5496*/ 5497sqlite3_backup *sqlite3_backup_init( 5498 sqlite3 *pDest, /* Destination database handle */ 5499 const char *zDestName, /* Destination database name */ 5500 sqlite3 *pSource, /* Source database handle */ 5501 const char *zSourceName /* Source database name */ 5502); 5503int sqlite3_backup_step(sqlite3_backup *p, int nPage); 5504int sqlite3_backup_finish(sqlite3_backup *p); 5505int sqlite3_backup_remaining(sqlite3_backup *p); 5506int sqlite3_backup_pagecount(sqlite3_backup *p); 5507 5508/* 5509** CAPI3REF: Unlock Notification 5510** EXPERIMENTAL 5511** 5512** ^When running in shared-cache mode, a database operation may fail with 5513** an [SQLITE_LOCKED] error if the required locks on the shared-cache or 5514** individual tables within the shared-cache cannot be obtained. See 5515** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 5516** ^This API may be used to register a callback that SQLite will invoke 5517** when the connection currently holding the required lock relinquishes it. 5518** ^This API is only available if the library was compiled with the 5519** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. 5520** 5521** See Also: [Using the SQLite Unlock Notification Feature]. 5522** 5523** ^Shared-cache locks are released when a database connection concludes 5524** its current transaction, either by committing it or rolling it back. 5525** 5526** ^When a connection (known as the blocked connection) fails to obtain a 5527** shared-cache lock and SQLITE_LOCKED is returned to the caller, the 5528** identity of the database connection (the blocking connection) that 5529** has locked the required resource is stored internally. ^After an 5530** application receives an SQLITE_LOCKED error, it may call the 5531** sqlite3_unlock_notify() method with the blocked connection handle as 5532** the first argument to register for a callback that will be invoked 5533** when the blocking connections current transaction is concluded. ^The 5534** callback is invoked from within the [sqlite3_step] or [sqlite3_close] 5535** call that concludes the blocking connections transaction. 5536** 5537** ^(If sqlite3_unlock_notify() is called in a multi-threaded application, 5538** there is a chance that the blocking connection will have already 5539** concluded its transaction by the time sqlite3_unlock_notify() is invoked. 5540** If this happens, then the specified callback is invoked immediately, 5541** from within the call to sqlite3_unlock_notify().)^ 5542** 5543** ^If the blocked connection is attempting to obtain a write-lock on a 5544** shared-cache table, and more than one other connection currently holds 5545** a read-lock on the same table, then SQLite arbitrarily selects one of 5546** the other connections to use as the blocking connection. 5547** 5548** ^(There may be at most one unlock-notify callback registered by a 5549** blocked connection. If sqlite3_unlock_notify() is called when the 5550** blocked connection already has a registered unlock-notify callback, 5551** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is 5552** called with a NULL pointer as its second argument, then any existing 5553** unlock-notify callback is cancelled. ^The blocked connections 5554** unlock-notify callback may also be canceled by closing the blocked 5555** connection using [sqlite3_close()]. 5556** 5557** The unlock-notify callback is not reentrant. If an application invokes 5558** any sqlite3_xxx API functions from within an unlock-notify callback, a 5559** crash or deadlock may be the result. 5560** 5561** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always 5562** returns SQLITE_OK. 5563** 5564** <b>Callback Invocation Details</b> 5565** 5566** When an unlock-notify callback is registered, the application provides a 5567** single void* pointer that is passed to the callback when it is invoked. 5568** However, the signature of the callback function allows SQLite to pass 5569** it an array of void* context pointers. The first argument passed to 5570** an unlock-notify callback is a pointer to an array of void* pointers, 5571** and the second is the number of entries in the array. 5572** 5573** When a blocking connections transaction is concluded, there may be 5574** more than one blocked connection that has registered for an unlock-notify 5575** callback. ^If two or more such blocked connections have specified the 5576** same callback function, then instead of invoking the callback function 5577** multiple times, it is invoked once with the set of void* context pointers 5578** specified by the blocked connections bundled together into an array. 5579** This gives the application an opportunity to prioritize any actions 5580** related to the set of unblocked database connections. 5581** 5582** <b>Deadlock Detection</b> 5583** 5584** Assuming that after registering for an unlock-notify callback a 5585** database waits for the callback to be issued before taking any further 5586** action (a reasonable assumption), then using this API may cause the 5587** application to deadlock. For example, if connection X is waiting for 5588** connection Y's transaction to be concluded, and similarly connection 5589** Y is waiting on connection X's transaction, then neither connection 5590** will proceed and the system may remain deadlocked indefinitely. 5591** 5592** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock 5593** detection. ^If a given call to sqlite3_unlock_notify() would put the 5594** system in a deadlocked state, then SQLITE_LOCKED is returned and no 5595** unlock-notify callback is registered. The system is said to be in 5596** a deadlocked state if connection A has registered for an unlock-notify 5597** callback on the conclusion of connection B's transaction, and connection 5598** B has itself registered for an unlock-notify callback when connection 5599** A's transaction is concluded. ^Indirect deadlock is also detected, so 5600** the system is also considered to be deadlocked if connection B has 5601** registered for an unlock-notify callback on the conclusion of connection 5602** C's transaction, where connection C is waiting on connection A. ^Any 5603** number of levels of indirection are allowed. 5604** 5605** <b>The "DROP TABLE" Exception</b> 5606** 5607** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 5608** always appropriate to call sqlite3_unlock_notify(). There is however, 5609** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, 5610** SQLite checks if there are any currently executing SELECT statements 5611** that belong to the same connection. If there are, SQLITE_LOCKED is 5612** returned. In this case there is no "blocking connection", so invoking 5613** sqlite3_unlock_notify() results in the unlock-notify callback being 5614** invoked immediately. If the application then re-attempts the "DROP TABLE" 5615** or "DROP INDEX" query, an infinite loop might be the result. 5616** 5617** One way around this problem is to check the extended error code returned 5618** by an sqlite3_step() call. ^(If there is a blocking connection, then the 5619** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in 5620** the special "DROP TABLE/INDEX" case, the extended error code is just 5621** SQLITE_LOCKED.)^ 5622*/ 5623int sqlite3_unlock_notify( 5624 sqlite3 *pBlocked, /* Waiting connection */ 5625 void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ 5626 void *pNotifyArg /* Argument to pass to xNotify */ 5627); 5628 5629 5630/* 5631** CAPI3REF: String Comparison 5632** EXPERIMENTAL 5633** 5634** ^The [sqlite3_strnicmp()] API allows applications and extensions to 5635** compare the contents of two buffers containing UTF-8 strings in a 5636** case-indendent fashion, using the same definition of case independence 5637** that SQLite uses internally when comparing identifiers. 5638*/ 5639int sqlite3_strnicmp(const char *, const char *, int); 5640 5641/* 5642** Undo the hack that converts floating point types to integer for 5643** builds on processors without floating point support. 5644*/ 5645#ifdef SQLITE_OMIT_FLOATING_POINT 5646# undef double 5647#endif 5648 5649#ifdef __cplusplus 5650} /* End of the 'extern "C"' block */ 5651#endif 5652#endif 5653