/* ** 2001 September 15 ** ** The author disclaims copyright to this source code. In place of ** a legal notice, here is a blessing: ** ** May you do good and not evil. ** May you find forgiveness for yourself and forgive others. ** May you share freely, never taking more than you give. ** ************************************************************************* ** This header file defines the interface that the SQLite library ** presents to client programs. If a C-function, structure, datatype, ** or constant definition does not appear in this file, then it is ** not a published API of SQLite, is subject to change without ** notice, and should not be referenced by programs that use SQLite. ** ** Some of the definitions that are in this file are marked as ** "experimental". Experimental interfaces are normally new ** features recently added to SQLite. We do not anticipate changes ** to experimental interfaces but reserve to make minor changes if ** experience from use "in the wild" suggest such changes are prudent. ** ** The official C-language API documentation for SQLite is derived ** from comments in this file. This file is the authoritative source ** on how SQLite interfaces are suppose to operate. ** ** The name of this file under configuration management is "sqlite.h.in". ** The makefile makes some minor changes to this file (such as inserting ** the version number) and changes its name to "sqlite3.h" as ** part of the build process. ** ** @(#) $Id: sqlite.h.in,v 1.440 2009/04/06 15:55:04 drh Exp $ */ #ifndef _SQLITE3_H_ #define _SQLITE3_H_ #include /* Needed for the definition of va_list */ /* ** Make sure we can call this stuff from C++. */ #ifdef __cplusplus extern "C" { #endif /* ** Add the ability to override 'extern' */ #ifndef SQLITE_EXTERN # define SQLITE_EXTERN extern #endif /* ** These no-op macros are used in front of interfaces to mark those ** interfaces as either deprecated or experimental. New applications ** should not use deprecated intrfaces - they are support for backwards ** compatibility only. Application writers should be aware that ** experimental interfaces are subject to change in point releases. ** ** These macros used to resolve to various kinds of compiler magic that ** would generate warning messages when they were used. But that ** compiler magic ended up generating such a flurry of bug reports ** that we have taken it all out and gone back to using simple ** noop macros. */ #define SQLITE_DEPRECATED #define SQLITE_EXPERIMENTAL /* ** Ensure these symbols were not defined by some previous header file. */ #ifdef SQLITE_VERSION # undef SQLITE_VERSION #endif #ifdef SQLITE_VERSION_NUMBER # undef SQLITE_VERSION_NUMBER #endif /* ** CAPI3REF: Compile-Time Library Version Numbers {H10010} ** ** The SQLITE_VERSION and SQLITE_VERSION_NUMBER #defines in ** the sqlite3.h file specify the version of SQLite with which ** that header file is associated. ** ** The "version" of SQLite is a string of the form "X.Y.Z". ** The phrase "alpha" or "beta" might be appended after the Z. ** The X value is major version number always 3 in SQLite3. ** The X value only changes when backwards compatibility is ** broken and we intend to never break backwards compatibility. ** The Y value is the minor version number and only changes when ** there are major feature enhancements that are forwards compatible ** but not backwards compatible. ** The Z value is the release number and is incremented with ** each release but resets back to 0 whenever Y is incremented. ** ** See also: [sqlite3_libversion()] and [sqlite3_libversion_number()]. ** ** Requirements: [H10011] [H10014] */ #define SQLITE_VERSION "3.6.13" #define SQLITE_VERSION_NUMBER 3006013 /* ** CAPI3REF: Run-Time Library Version Numbers {H10020} ** KEYWORDS: sqlite3_version ** ** These features provide the same information as the [SQLITE_VERSION] ** and [SQLITE_VERSION_NUMBER] #defines in the header, but are associated ** with the library instead of the header file. Cautious programmers might ** include a check in their application to verify that ** sqlite3_libversion_number() always returns the value ** [SQLITE_VERSION_NUMBER]. ** ** The sqlite3_libversion() function returns the same information as is ** in the sqlite3_version[] string constant. The function is provided ** for use in DLLs since DLL users usually do not have direct access to string ** constants within the DLL. ** ** Requirements: [H10021] [H10022] [H10023] */ SQLITE_EXTERN const char sqlite3_version[]; const char *sqlite3_libversion(void); int sqlite3_libversion_number(void); /* ** CAPI3REF: Test To See If The Library Is Threadsafe {H10100} ** ** SQLite can be compiled with or without mutexes. When ** the [SQLITE_THREADSAFE] C preprocessor macro 1 or 2, mutexes ** are enabled and SQLite is threadsafe. When the ** [SQLITE_THREADSAFE] macro is 0, ** the mutexes are omitted. Without the mutexes, it is not safe ** to use SQLite concurrently from more than one thread. ** ** Enabling mutexes incurs a measurable performance penalty. ** So if speed is of utmost importance, it makes sense to disable ** the mutexes. But for maximum safety, mutexes should be enabled. ** The default behavior is for mutexes to be enabled. ** ** This interface can be used by a program to make sure that the ** version of SQLite that it is linking against was compiled with ** the desired setting of the [SQLITE_THREADSAFE] macro. ** ** This interface only reports on the compile-time mutex setting ** of the [SQLITE_THREADSAFE] flag. If SQLite is compiled with ** SQLITE_THREADSAFE=1 then mutexes are enabled by default but ** can be fully or partially disabled using a call to [sqlite3_config()] ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD], ** or [SQLITE_CONFIG_MUTEX]. The return value of this function shows ** only the default compile-time setting, not any run-time changes ** to that setting. ** ** See the [threading mode] documentation for additional information. ** ** Requirements: [H10101] [H10102] */ int sqlite3_threadsafe(void); /* ** CAPI3REF: Database Connection Handle {H12000} ** KEYWORDS: {database connection} {database connections} ** ** Each open SQLite database is represented by a pointer to an instance of ** the opaque structure named "sqlite3". It is useful to think of an sqlite3 ** pointer as an object. The [sqlite3_open()], [sqlite3_open16()], and ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()] ** is its destructor. There are many other interfaces (such as ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and ** [sqlite3_busy_timeout()] to name but three) that are methods on an ** sqlite3 object. */ typedef struct sqlite3 sqlite3; /* ** CAPI3REF: 64-Bit Integer Types {H10200} ** KEYWORDS: sqlite_int64 sqlite_uint64 ** ** Because there is no cross-platform way to specify 64-bit integer types ** SQLite includes typedefs for 64-bit signed and unsigned integers. ** ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions. ** The sqlite_int64 and sqlite_uint64 types are supported for backwards ** compatibility only. ** ** Requirements: [H10201] [H10202] */ #ifdef SQLITE_INT64_TYPE typedef SQLITE_INT64_TYPE sqlite_int64; typedef unsigned SQLITE_INT64_TYPE sqlite_uint64; #elif defined(_MSC_VER) || defined(__BORLANDC__) typedef __int64 sqlite_int64; typedef unsigned __int64 sqlite_uint64; #else typedef long long int sqlite_int64; typedef unsigned long long int sqlite_uint64; #endif typedef sqlite_int64 sqlite3_int64; typedef sqlite_uint64 sqlite3_uint64; /* ** If compiling for a processor that lacks floating point support, ** substitute integer for floating-point. */ #ifdef SQLITE_OMIT_FLOATING_POINT # define double sqlite3_int64 #endif /* ** CAPI3REF: Closing A Database Connection {H12010} ** ** This routine is the destructor for the [sqlite3] object. ** ** Applications should [sqlite3_finalize | finalize] all [prepared statements] ** and [sqlite3_blob_close | close] all [BLOB handles] associated with ** the [sqlite3] object prior to attempting to close the object. ** The [sqlite3_next_stmt()] interface can be used to locate all ** [prepared statements] associated with a [database connection] if desired. ** Typical code might look like this: ** ** 
** sqlite3_stmt *pStmt;
** while( (pStmt = sqlite3_next_stmt(db, 0))!=0 ){
**     sqlite3_finalize(pStmt);
** }
**
** ** If [sqlite3_close()] is invoked while a transaction is open, ** the transaction is automatically rolled back. ** ** The C parameter to [sqlite3_close(C)] must be either a NULL ** pointer or an [sqlite3] object pointer obtained ** from [sqlite3_open()], [sqlite3_open16()], or ** [sqlite3_open_v2()], and not previously closed. ** ** Requirements: ** [H12011] [H12012] [H12013] [H12014] [H12015] [H12019] */ int sqlite3_close(sqlite3 *); /* ** The type for a callback function. ** This is legacy and deprecated. It is included for historical ** compatibility and is not documented. */ typedef int (*sqlite3_callback)(void*,int,char**, char**); /* ** CAPI3REF: One-Step Query Execution Interface {H12100} ** ** The sqlite3_exec() interface is a convenient way of running one or more ** SQL statements without having to write a lot of C code. The UTF-8 encoded ** SQL statements are passed in as the second parameter to sqlite3_exec(). ** The statements are evaluated one by one until either an error or ** an interrupt is encountered, or until they are all done. The 3rd parameter ** is an optional callback that is invoked once for each row of any query ** results produced by the SQL statements. The 5th parameter tells where ** to write any error messages. ** ** The error message passed back through the 5th parameter is held ** in memory obtained from [sqlite3_malloc()]. To avoid a memory leak, ** the calling application should call [sqlite3_free()] on any error ** message returned through the 5th parameter when it has finished using ** the error message. ** ** If the SQL statement in the 2nd parameter is NULL or an empty string ** or a string containing only whitespace and comments, then no SQL ** statements are evaluated and the database is not changed. ** ** The sqlite3_exec() interface is implemented in terms of ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. ** The sqlite3_exec() routine does nothing to the database that cannot be done ** by [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()]. ** ** The first parameter to [sqlite3_exec()] must be an valid and open ** [database connection]. ** ** The database connection must not be closed while ** [sqlite3_exec()] is running. ** ** The calling function should use [sqlite3_free()] to free ** the memory that *errmsg is left pointing at once the error ** message is no longer needed. ** ** The SQL statement text in the 2nd parameter to [sqlite3_exec()] ** must remain unchanged while [sqlite3_exec()] is running. ** ** Requirements: ** [H12101] [H12102] [H12104] [H12105] [H12107] [H12110] [H12113] [H12116] ** [H12119] [H12122] [H12125] [H12131] [H12134] [H12137] [H12138] */ int sqlite3_exec( sqlite3*, /* An open database */ const char *sql, /* SQL to be evaluated */ int (*callback)(void*,int,char**,char**), /* Callback function */ void *, /* 1st argument to callback */ char **errmsg /* Error msg written here */ ); /* ** CAPI3REF: Result Codes {H10210} ** KEYWORDS: SQLITE_OK {error code} {error codes} ** KEYWORDS: {result code} {result codes} ** ** Many SQLite functions return an integer result code from the set shown ** here in order to indicates success or failure. ** ** New error codes may be added in future versions of SQLite. ** ** See also: [SQLITE_IOERR_READ | extended result codes] */ #define SQLITE_OK 0 /* Successful result */ /* beginning-of-error-codes */ #define SQLITE_ERROR 1 /* SQL error or missing database */ #define SQLITE_INTERNAL 2 /* Internal logic error in SQLite */ #define SQLITE_PERM 3 /* Access permission denied */ #define SQLITE_ABORT 4 /* Callback routine requested an abort */ #define SQLITE_BUSY 5 /* The database file is locked */ #define SQLITE_LOCKED 6 /* A table in the database is locked */ #define SQLITE_NOMEM 7 /* A malloc() failed */ #define SQLITE_READONLY 8 /* Attempt to write a readonly database */ #define SQLITE_INTERRUPT 9 /* Operation terminated by sqlite3_interrupt()*/ #define SQLITE_IOERR 10 /* Some kind of disk I/O error occurred */ #define SQLITE_CORRUPT 11 /* The database disk image is malformed */ #define SQLITE_NOTFOUND 12 /* NOT USED. Table or record not found */ #define SQLITE_FULL 13 /* Insertion failed because database is full */ #define SQLITE_CANTOPEN 14 /* Unable to open the database file */ #define SQLITE_PROTOCOL 15 /* NOT USED. Database lock protocol error */ #define SQLITE_EMPTY 16 /* Database is empty */ #define SQLITE_SCHEMA 17 /* The database schema changed */ #define SQLITE_TOOBIG 18 /* String or BLOB exceeds size limit */ #define SQLITE_CONSTRAINT 19 /* Abort due to constraint violation */ #define SQLITE_MISMATCH 20 /* Data type mismatch */ #define SQLITE_MISUSE 21 /* Library used incorrectly */ #define SQLITE_NOLFS 22 /* Uses OS features not supported on host */ #define SQLITE_AUTH 23 /* Authorization denied */ #define SQLITE_FORMAT 24 /* Auxiliary database format error */ #define SQLITE_RANGE 25 /* 2nd parameter to sqlite3_bind out of range */ #define SQLITE_NOTADB 26 /* File opened that is not a database file */ #define SQLITE_ROW 100 /* sqlite3_step() has another row ready */ #define SQLITE_DONE 101 /* sqlite3_step() has finished executing */ /* end-of-error-codes */ /* ** CAPI3REF: Extended Result Codes {H10220} ** KEYWORDS: {extended error code} {extended error codes} ** KEYWORDS: {extended result code} {extended result codes} ** ** In its default configuration, SQLite API routines return one of 26 integer ** [SQLITE_OK | result codes]. However, experience has shown that many of ** these result codes are too coarse-grained. They do not provide as ** much information about problems as programmers might like. In an effort to ** address this, newer versions of SQLite (version 3.3.8 and later) include ** support for additional result codes that provide more detailed information ** about errors. The extended result codes are enabled or disabled ** on a per database connection basis using the ** [sqlite3_extended_result_codes()] API. ** ** Some of the available extended result codes are listed here. ** One may expect the number of extended result codes will be expand ** over time. Software that uses extended result codes should expect ** to see new result codes in future releases of SQLite. ** ** The SQLITE_OK result code will never be extended. It will always ** be exactly zero. */ #define SQLITE_IOERR_READ (SQLITE_IOERR | (1<<8)) #define SQLITE_IOERR_SHORT_READ (SQLITE_IOERR | (2<<8)) #define SQLITE_IOERR_WRITE (SQLITE_IOERR | (3<<8)) #define SQLITE_IOERR_FSYNC (SQLITE_IOERR | (4<<8)) #define SQLITE_IOERR_DIR_FSYNC (SQLITE_IOERR | (5<<8)) #define SQLITE_IOERR_TRUNCATE (SQLITE_IOERR | (6<<8)) #define SQLITE_IOERR_FSTAT (SQLITE_IOERR | (7<<8)) #define SQLITE_IOERR_UNLOCK (SQLITE_IOERR | (8<<8)) #define SQLITE_IOERR_RDLOCK (SQLITE_IOERR | (9<<8)) #define SQLITE_IOERR_DELETE (SQLITE_IOERR | (10<<8)) #define SQLITE_IOERR_BLOCKED (SQLITE_IOERR | (11<<8)) #define SQLITE_IOERR_NOMEM (SQLITE_IOERR | (12<<8)) #define SQLITE_IOERR_ACCESS (SQLITE_IOERR | (13<<8)) #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8)) #define SQLITE_IOERR_LOCK (SQLITE_IOERR | (15<<8)) #define SQLITE_IOERR_CLOSE (SQLITE_IOERR | (16<<8)) #define SQLITE_IOERR_DIR_CLOSE (SQLITE_IOERR | (17<<8)) #define SQLITE_LOCKED_SHAREDCACHE (SQLITE_LOCKED | (1<<8) ) /* ** CAPI3REF: Flags For File Open Operations {H10230} ** ** These bit values are intended for use in the ** 3rd parameter to the [sqlite3_open_v2()] interface and ** in the 4th parameter to the xOpen method of the ** [sqlite3_vfs] object. */ #define SQLITE_OPEN_READONLY 0x00000001 #define SQLITE_OPEN_READWRITE 0x00000002 #define SQLITE_OPEN_CREATE 0x00000004 #define SQLITE_OPEN_DELETEONCLOSE 0x00000008 #define SQLITE_OPEN_EXCLUSIVE 0x00000010 #define SQLITE_OPEN_MAIN_DB 0x00000100 #define SQLITE_OPEN_TEMP_DB 0x00000200 #define SQLITE_OPEN_TRANSIENT_DB 0x00000400 #define SQLITE_OPEN_MAIN_JOURNAL 0x00000800 #define SQLITE_OPEN_TEMP_JOURNAL 0x00001000 #define SQLITE_OPEN_SUBJOURNAL 0x00002000 #define SQLITE_OPEN_MASTER_JOURNAL 0x00004000 #define SQLITE_OPEN_NOMUTEX 0x00008000 #define SQLITE_OPEN_FULLMUTEX 0x00010000 /* ** CAPI3REF: Device Characteristics {H10240} ** ** The xDeviceCapabilities method of the [sqlite3_io_methods] ** object returns an integer which is a vector of the these ** bit values expressing I/O characteristics of the mass storage ** device that holds the file that the [sqlite3_io_methods] ** refers to. ** ** The SQLITE_IOCAP_ATOMIC property means that all writes of ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values ** mean that writes of blocks that are nnn bytes in size and ** are aligned to an address which is an integer multiple of ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means ** that when data is appended to a file, the data is appended ** first then the size of the file is extended, never the other ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that ** information is written to disk in the same order as calls ** to xWrite(). */ #define SQLITE_IOCAP_ATOMIC 0x00000001 #define SQLITE_IOCAP_ATOMIC512 0x00000002 #define SQLITE_IOCAP_ATOMIC1K 0x00000004 #define SQLITE_IOCAP_ATOMIC2K 0x00000008 #define SQLITE_IOCAP_ATOMIC4K 0x00000010 #define SQLITE_IOCAP_ATOMIC8K 0x00000020 #define SQLITE_IOCAP_ATOMIC16K 0x00000040 #define SQLITE_IOCAP_ATOMIC32K 0x00000080 #define SQLITE_IOCAP_ATOMIC64K 0x00000100 #define SQLITE_IOCAP_SAFE_APPEND 0x00000200 #define SQLITE_IOCAP_SEQUENTIAL 0x00000400 /* ** CAPI3REF: File Locking Levels {H10250} ** ** SQLite uses one of these integer values as the second ** argument to calls it makes to the xLock() and xUnlock() methods ** of an [sqlite3_io_methods] object. */ #define SQLITE_LOCK_NONE 0 #define SQLITE_LOCK_SHARED 1 #define SQLITE_LOCK_RESERVED 2 #define SQLITE_LOCK_PENDING 3 #define SQLITE_LOCK_EXCLUSIVE 4 /* ** CAPI3REF: Synchronization Type Flags {H10260} ** ** When SQLite invokes the xSync() method of an ** [sqlite3_io_methods] object it uses a combination of ** these integer values as the second argument. ** ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the ** sync operation only needs to flush data to mass storage. Inode ** information need not be flushed. If the lower four bits of the flag ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics. ** If the lower four bits equal SQLITE_SYNC_FULL, that means ** to use Mac OS X style fullsync instead of fsync(). */ #define SQLITE_SYNC_NORMAL 0x00002 #define SQLITE_SYNC_FULL 0x00003 #define SQLITE_SYNC_DATAONLY 0x00010 /* ** CAPI3REF: OS Interface Open File Handle {H11110} ** ** An [sqlite3_file] object represents an open file in the OS ** interface layer. Individual OS interface implementations will ** want to subclass this object by appending additional fields ** for their own use. The pMethods entry is a pointer to an ** [sqlite3_io_methods] object that defines methods for performing ** I/O operations on the open file. */ typedef struct sqlite3_file sqlite3_file; struct sqlite3_file { const struct sqlite3_io_methods *pMethods; /* Methods for an open file */ }; /* ** CAPI3REF: OS Interface File Virtual Methods Object {H11120} ** ** Every file opened by the [sqlite3_vfs] xOpen method populates an ** [sqlite3_file] object (or, more commonly, a subclass of the ** [sqlite3_file] object) with a pointer to an instance of this object. ** This object defines the methods used to perform various operations ** against the open file represented by the [sqlite3_file] object. ** ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or ** [SQLITE_SYNC_FULL]. The first choice is the normal fsync(). ** The second choice is a Mac OS X style fullsync. The [SQLITE_SYNC_DATAONLY] ** flag may be ORed in to indicate that only the data of the file ** and not its inode needs to be synced. ** ** The integer values to xLock() and xUnlock() are one of **
    **
  • [SQLITE_LOCK_NONE], **
  • [SQLITE_LOCK_SHARED], **
  • [SQLITE_LOCK_RESERVED], **
  • [SQLITE_LOCK_PENDING], or **
  • [SQLITE_LOCK_EXCLUSIVE]. **
** xLock() increases the lock. xUnlock() decreases the lock. ** The xCheckReservedLock() method checks whether any database connection, ** either in this process or in some other process, is holding a RESERVED, ** PENDING, or EXCLUSIVE lock on the file. It returns true ** if such a lock exists and false otherwise. ** ** The xFileControl() method is a generic interface that allows custom ** VFS implementations to directly control an open file using the ** [sqlite3_file_control()] interface. The second "op" argument is an ** integer opcode. The third argument is a generic pointer intended to ** point to a structure that may contain arguments or space in which to ** write return values. Potential uses for xFileControl() might be ** functions to enable blocking locks with timeouts, to change the ** locking strategy (for example to use dot-file locks), to inquire ** about the status of a lock, or to break stale locks. The SQLite ** core reserves all opcodes less than 100 for its own use. ** A [SQLITE_FCNTL_LOCKSTATE | list of opcodes] less than 100 is available. ** Applications that define a custom xFileControl method should use opcodes ** greater than 100 to avoid conflicts. ** ** The xSectorSize() method returns the sector size of the ** device that underlies the file. The sector size is the ** minimum write that can be performed without disturbing ** other bytes in the file. The xDeviceCharacteristics() ** method returns a bit vector describing behaviors of the ** underlying device: ** **
    **
  • [SQLITE_IOCAP_ATOMIC] **
  • [SQLITE_IOCAP_ATOMIC512] **
  • [SQLITE_IOCAP_ATOMIC1K] **
  • [SQLITE_IOCAP_ATOMIC2K] **
  • [SQLITE_IOCAP_ATOMIC4K] **
  • [SQLITE_IOCAP_ATOMIC8K] **
  • [SQLITE_IOCAP_ATOMIC16K] **
  • [SQLITE_IOCAP_ATOMIC32K] **
  • [SQLITE_IOCAP_ATOMIC64K] **
  • [SQLITE_IOCAP_SAFE_APPEND] **
  • [SQLITE_IOCAP_SEQUENTIAL] **
** ** The SQLITE_IOCAP_ATOMIC property means that all writes of ** any size are atomic. The SQLITE_IOCAP_ATOMICnnn values ** mean that writes of blocks that are nnn bytes in size and ** are aligned to an address which is an integer multiple of ** nnn are atomic. The SQLITE_IOCAP_SAFE_APPEND value means ** that when data is appended to a file, the data is appended ** first then the size of the file is extended, never the other ** way around. The SQLITE_IOCAP_SEQUENTIAL property means that ** information is written to disk in the same order as calls ** to xWrite(). ** ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill ** in the unread portions of the buffer with zeros. A VFS that ** fails to zero-fill short reads might seem to work. However, ** failure to zero-fill short reads will eventually lead to ** database corruption. */ typedef struct sqlite3_io_methods sqlite3_io_methods; struct sqlite3_io_methods { int iVersion; int (*xClose)(sqlite3_file*); int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst); int (*xTruncate)(sqlite3_file*, sqlite3_int64 size); int (*xSync)(sqlite3_file*, int flags); int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize); int (*xLock)(sqlite3_file*, int); int (*xUnlock)(sqlite3_file*, int); int (*xCheckReservedLock)(sqlite3_file*, int *pResOut); int (*xFileControl)(sqlite3_file*, int op, void *pArg); int (*xSectorSize)(sqlite3_file*); int (*xDeviceCharacteristics)(sqlite3_file*); /* Additional methods may be added in future releases */ }; /* ** CAPI3REF: Standard File Control Opcodes {H11310} ** ** These integer constants are opcodes for the xFileControl method ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()] ** interface. ** ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging. This ** opcode causes the xFileControl method to write the current state of ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED], ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE]) ** into an integer that the pArg argument points to. This capability ** is used during testing and only needs to be supported when SQLITE_TEST ** is defined. */ #define SQLITE_FCNTL_LOCKSTATE 1 #define SQLITE_GET_LOCKPROXYFILE 2 #define SQLITE_SET_LOCKPROXYFILE 3 #define SQLITE_LAST_ERRNO 4 /* ** CAPI3REF: Mutex Handle {H17110} ** ** The mutex module within SQLite defines [sqlite3_mutex] to be an ** abstract type for a mutex object. The SQLite core never looks ** at the internal representation of an [sqlite3_mutex]. It only ** deals with pointers to the [sqlite3_mutex] object. ** ** Mutexes are created using [sqlite3_mutex_alloc()]. */ typedef struct sqlite3_mutex sqlite3_mutex; /* ** CAPI3REF: OS Interface Object {H11140} ** ** An instance of the sqlite3_vfs object defines the interface between ** the SQLite core and the underlying operating system. The "vfs" ** in the name of the object stands for "virtual file system". ** ** The value of the iVersion field is initially 1 but may be larger in ** future versions of SQLite. Additional fields may be appended to this ** object when the iVersion value is increased. Note that the structure ** of the sqlite3_vfs object changes in the transaction between ** SQLite version 3.5.9 and 3.6.0 and yet the iVersion field was not ** modified. ** ** The szOsFile field is the size of the subclassed [sqlite3_file] ** structure used by this VFS. mxPathname is the maximum length of ** a pathname in this VFS. ** ** Registered sqlite3_vfs objects are kept on a linked list formed by ** the pNext pointer. The [sqlite3_vfs_register()] ** and [sqlite3_vfs_unregister()] interfaces manage this list ** in a thread-safe way. The [sqlite3_vfs_find()] interface ** searches the list. Neither the application code nor the VFS ** implementation should use the pNext pointer. ** ** The pNext field is the only field in the sqlite3_vfs ** structure that SQLite will ever modify. SQLite will only access ** or modify this field while holding a particular static mutex. ** The application should never modify anything within the sqlite3_vfs ** object once the object has been registered. ** ** The zName field holds the name of the VFS module. The name must ** be unique across all VFS modules. ** ** SQLite will guarantee that the zFilename parameter to xOpen ** is either a NULL pointer or string obtained ** from xFullPathname(). SQLite further guarantees that ** the string will be valid and unchanged until xClose() is ** called. Because of the previous sentense, ** the [sqlite3_file] can safely store a pointer to the ** filename if it needs to remember the filename for some reason. ** If the zFilename parameter is xOpen is a NULL pointer then xOpen ** must invite its own temporary name for the file. Whenever the ** xFilename parameter is NULL it will also be the case that the ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE]. ** ** The flags argument to xOpen() includes all bits set in ** the flags argument to [sqlite3_open_v2()]. Or if [sqlite3_open()] ** or [sqlite3_open16()] is used, then flags includes at least ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. ** If xOpen() opens a file read-only then it sets *pOutFlags to ** include [SQLITE_OPEN_READONLY]. Other bits in *pOutFlags may be set. ** ** SQLite will also add one of the following flags to the xOpen() ** call, depending on the object being opened: ** **
    **
  • [SQLITE_OPEN_MAIN_DB] **
  • [SQLITE_OPEN_MAIN_JOURNAL] **
  • [SQLITE_OPEN_TEMP_DB] **
  • [SQLITE_OPEN_TEMP_JOURNAL] **
  • [SQLITE_OPEN_TRANSIENT_DB] **
  • [SQLITE_OPEN_SUBJOURNAL] **
  • [SQLITE_OPEN_MASTER_JOURNAL] **
** ** The file I/O implementation can use the object type flags to ** change the way it deals with files. For example, an application ** that does not care about crash recovery or rollback might make ** the open of a journal file a no-op. Writes to this journal would ** also be no-ops, and any attempt to read the journal would return ** SQLITE_IOERR. Or the implementation might recognize that a database ** file will be doing page-aligned sector reads and writes in a random ** order and set up its I/O subsystem accordingly. ** ** SQLite might also add one of the following flags to the xOpen method: ** **
    **
  • [SQLITE_OPEN_DELETEONCLOSE] **
  • [SQLITE_OPEN_EXCLUSIVE] **
** ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be ** deleted when it is closed. The [SQLITE_OPEN_DELETEONCLOSE] ** will be set for TEMP databases, journals and for subjournals. ** ** The [SQLITE_OPEN_EXCLUSIVE] flag means the file should be opened ** for exclusive access. This flag is set for all files except ** for the main database file. ** ** At least szOsFile bytes of memory are allocated by SQLite ** to hold the [sqlite3_file] structure passed as the third ** argument to xOpen. The xOpen method does not have to ** allocate the structure; it should just fill it in. ** ** The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ] ** to test whether a file is at least readable. The file can be a ** directory. ** ** SQLite will always allocate at least mxPathname+1 bytes for the ** output buffer xFullPathname. The exact size of the output buffer ** is also passed as a parameter to both methods. If the output buffer ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is ** handled as a fatal error by SQLite, vfs implementations should endeavor ** to prevent this by setting mxPathname to a sufficiently large value. ** ** The xRandomness(), xSleep(), and xCurrentTime() interfaces ** are not strictly a part of the filesystem, but they are ** included in the VFS structure for completeness. ** The xRandomness() function attempts to return nBytes bytes ** of good-quality randomness into zOut. The return value is ** the actual number of bytes of randomness obtained. ** The xSleep() method causes the calling thread to sleep for at ** least the number of microseconds given. The xCurrentTime() ** method returns a Julian Day Number for the current date and time. ** */ typedef struct sqlite3_vfs sqlite3_vfs; struct sqlite3_vfs { int iVersion; /* Structure version number */ int szOsFile; /* Size of subclassed sqlite3_file */ int mxPathname; /* Maximum file pathname length */ sqlite3_vfs *pNext; /* Next registered VFS */ const char *zName; /* Name of this virtual file system */ void *pAppData; /* Pointer to application-specific data */ int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*, int flags, int *pOutFlags); int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir); int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut); int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut); void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename); void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg); void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void); void (*xDlClose)(sqlite3_vfs*, void*); int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut); int (*xSleep)(sqlite3_vfs*, int microseconds); int (*xCurrentTime)(sqlite3_vfs*, double*); int (*xGetLastError)(sqlite3_vfs*, int, char *); /* New fields may be appended in figure versions. The iVersion ** value will increment whenever this happens. */ }; /* ** CAPI3REF: Flags for the xAccess VFS method {H11190} ** ** These integer constants can be used as the third parameter to ** the xAccess method of an [sqlite3_vfs] object. {END} They determine ** what kind of permissions the xAccess method is looking for. ** With SQLITE_ACCESS_EXISTS, the xAccess method ** simply checks whether the file exists. ** With SQLITE_ACCESS_READWRITE, the xAccess method ** checks whether the file is both readable and writable. ** With SQLITE_ACCESS_READ, the xAccess method ** checks whether the file is readable. */ #define SQLITE_ACCESS_EXISTS 0 #define SQLITE_ACCESS_READWRITE 1 #define SQLITE_ACCESS_READ 2 /* ** CAPI3REF: Initialize The SQLite Library {H10130} ** ** The sqlite3_initialize() routine initializes the ** SQLite library. The sqlite3_shutdown() routine ** deallocates any resources that were allocated by sqlite3_initialize(). ** ** A call to sqlite3_initialize() is an "effective" call if it is ** the first time sqlite3_initialize() is invoked during the lifetime of ** the process, or if it is the first time sqlite3_initialize() is invoked ** following a call to sqlite3_shutdown(). Only an effective call ** of sqlite3_initialize() does any initialization. All other calls ** are harmless no-ops. ** ** Among other things, sqlite3_initialize() shall invoke ** sqlite3_os_init(). Similarly, sqlite3_shutdown() ** shall invoke sqlite3_os_end(). ** ** The sqlite3_initialize() routine returns [SQLITE_OK] on success. ** If for some reason, sqlite3_initialize() is unable to initialize ** the library (perhaps it is unable to allocate a needed resource such ** as a mutex) it returns an [error code] other than [SQLITE_OK]. ** ** The sqlite3_initialize() routine is called internally by many other ** SQLite interfaces so that an application usually does not need to ** invoke sqlite3_initialize() directly. For example, [sqlite3_open()] ** calls sqlite3_initialize() so the SQLite library will be automatically ** initialized when [sqlite3_open()] is called if it has not be initialized ** already. However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT] ** compile-time option, then the automatic calls to sqlite3_initialize() ** are omitted and the application must call sqlite3_initialize() directly ** prior to using any other SQLite interface. For maximum portability, ** it is recommended that applications always invoke sqlite3_initialize() ** directly prior to using any other SQLite interface. Future releases ** of SQLite may require this. In other words, the behavior exhibited ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the ** default behavior in some future release of SQLite. ** ** The sqlite3_os_init() routine does operating-system specific ** initialization of the SQLite library. The sqlite3_os_end() ** routine undoes the effect of sqlite3_os_init(). Typical tasks ** performed by these routines include allocation or deallocation ** of static resources, initialization of global variables, ** setting up a default [sqlite3_vfs] module, or setting up ** a default configuration using [sqlite3_config()]. ** ** The application should never invoke either sqlite3_os_init() ** or sqlite3_os_end() directly. The application should only invoke ** sqlite3_initialize() and sqlite3_shutdown(). The sqlite3_os_init() ** interface is called automatically by sqlite3_initialize() and ** sqlite3_os_end() is called by sqlite3_shutdown(). Appropriate ** implementations for sqlite3_os_init() and sqlite3_os_end() ** are built into SQLite when it is compiled for unix, windows, or os/2. ** When built for other platforms (using the [SQLITE_OS_OTHER=1] compile-time ** option) the application must supply a suitable implementation for ** sqlite3_os_init() and sqlite3_os_end(). An application-supplied ** implementation of sqlite3_os_init() or sqlite3_os_end() ** must return [SQLITE_OK] on success and some other [error code] upon ** failure. */ int sqlite3_initialize(void); int sqlite3_shutdown(void); int sqlite3_os_init(void); int sqlite3_os_end(void); /* ** CAPI3REF: Configuring The SQLite Library {H14100} ** EXPERIMENTAL ** ** The sqlite3_config() interface is used to make global configuration ** changes to SQLite in order to tune SQLite to the specific needs of ** the application. The default configuration is recommended for most ** applications and so this routine is usually not necessary. It is ** provided to support rare applications with unusual needs. ** ** The sqlite3_config() interface is not threadsafe. The application ** must insure that no other SQLite interfaces are invoked by other ** threads while sqlite3_config() is running. Furthermore, sqlite3_config() ** may only be invoked prior to library initialization using ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()]. ** Note, however, that sqlite3_config() can be called as part of the ** implementation of an application-defined [sqlite3_os_init()]. ** ** The first argument to sqlite3_config() is an integer ** [SQLITE_CONFIG_SINGLETHREAD | configuration option] that determines ** what property of SQLite is to be configured. Subsequent arguments ** vary depending on the [SQLITE_CONFIG_SINGLETHREAD | configuration option] ** in the first argument. ** ** When a configuration option is set, sqlite3_config() returns [SQLITE_OK]. ** If the option is unknown or SQLite is unable to set the option ** then this routine returns a non-zero [error code]. ** ** Requirements: ** [H14103] [H14106] [H14120] [H14123] [H14126] [H14129] [H14132] [H14135] ** [H14138] [H14141] [H14144] [H14147] [H14150] [H14153] [H14156] [H14159] ** [H14162] [H14165] [H14168] */ SQLITE_EXPERIMENTAL int sqlite3_config(int, ...); /* ** CAPI3REF: Configure database connections {H14200} ** EXPERIMENTAL ** ** The sqlite3_db_config() interface is used to make configuration ** changes to a [database connection]. The interface is similar to ** [sqlite3_config()] except that the changes apply to a single ** [database connection] (specified in the first argument). The ** sqlite3_db_config() interface can only be used immediately after ** the database connection is created using [sqlite3_open()], ** [sqlite3_open16()], or [sqlite3_open_v2()]. ** ** The second argument to sqlite3_db_config(D,V,...) is the ** configuration verb - an integer code that indicates what ** aspect of the [database connection] is being configured. ** The only choice for this value is [SQLITE_DBCONFIG_LOOKASIDE]. ** New verbs are likely to be added in future releases of SQLite. ** Additional arguments depend on the verb. ** ** Requirements: ** [H14203] [H14206] [H14209] [H14212] [H14215] */ SQLITE_EXPERIMENTAL int sqlite3_db_config(sqlite3*, int op, ...); /* ** CAPI3REF: Memory Allocation Routines {H10155} ** EXPERIMENTAL ** ** An instance of this object defines the interface between SQLite ** and low-level memory allocation routines. ** ** This object is used in only one place in the SQLite interface. ** A pointer to an instance of this object is the argument to ** [sqlite3_config()] when the configuration option is ** [SQLITE_CONFIG_MALLOC]. By creating an instance of this object ** and passing it to [sqlite3_config()] during configuration, an ** application can specify an alternative memory allocation subsystem ** for SQLite to use for all of its dynamic memory needs. ** ** Note that SQLite comes with a built-in memory allocator that is ** perfectly adequate for the overwhelming majority of applications ** and that this object is only useful to a tiny minority of applications ** with specialized memory allocation requirements. This object is ** also used during testing of SQLite in order to specify an alternative ** memory allocator that simulates memory out-of-memory conditions in ** order to verify that SQLite recovers gracefully from such ** conditions. ** ** The xMalloc, xFree, and xRealloc methods must work like the ** malloc(), free(), and realloc() functions from the standard library. ** ** xSize should return the allocated size of a memory allocation ** previously obtained from xMalloc or xRealloc. The allocated size ** is always at least as big as the requested size but may be larger. ** ** The xRoundup method returns what would be the allocated size of ** a memory allocation given a particular requested size. Most memory ** allocators round up memory allocations at least to the next multiple ** of 8. Some allocators round up to a larger multiple or to a power of 2. ** ** The xInit method initializes the memory allocator. (For example, ** it might allocate any require mutexes or initialize internal data ** structures. The xShutdown method is invoked (indirectly) by ** [sqlite3_shutdown()] and should deallocate any resources acquired ** by xInit. The pAppData pointer is used as the only parameter to ** xInit and xShutdown. */ typedef struct sqlite3_mem_methods sqlite3_mem_methods; struct sqlite3_mem_methods { void *(*xMalloc)(int); /* Memory allocation function */ void (*xFree)(void*); /* Free a prior allocation */ void *(*xRealloc)(void*,int); /* Resize an allocation */ int (*xSize)(void*); /* Return the size of an allocation */ int (*xRoundup)(int); /* Round up request size to allocation size */ int (*xInit)(void*); /* Initialize the memory allocator */ void (*xShutdown)(void*); /* Deinitialize the memory allocator */ void *pAppData; /* Argument to xInit() and xShutdown() */ }; /* ** CAPI3REF: Configuration Options {H10160} ** EXPERIMENTAL ** ** These constants are the available integer configuration options that ** can be passed as the first argument to the [sqlite3_config()] interface. ** ** New configuration options may be added in future releases of SQLite. ** Existing configuration options might be discontinued. Applications ** should check the return code from [sqlite3_config()] to make sure that ** the call worked. The [sqlite3_config()] interface will return a ** non-zero [error code] if a discontinued or unsupported configuration option ** is invoked. ** **
**
SQLITE_CONFIG_SINGLETHREAD
**
There are no arguments to this option. This option disables ** all mutexing and puts SQLite into a mode where it can only be used ** by a single thread.
** **
SQLITE_CONFIG_MULTITHREAD
**
There are no arguments to this option. This option disables ** mutexing on [database connection] and [prepared statement] objects. ** The application is responsible for serializing access to ** [database connections] and [prepared statements]. But other mutexes ** are enabled so that SQLite will be safe to use in a multi-threaded ** environment as long as no two threads attempt to use the same ** [database connection] at the same time. See the [threading mode] ** documentation for additional information.
** **
SQLITE_CONFIG_SERIALIZED
**
There are no arguments to this option. This option enables ** all mutexes including the recursive ** mutexes on [database connection] and [prepared statement] objects. ** In this mode (which is the default when SQLite is compiled with ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access ** to [database connections] and [prepared statements] so that the ** application is free to use the same [database connection] or the ** same [prepared statement] in different threads at the same time. ** See the [threading mode] documentation for additional information.
** **
SQLITE_CONFIG_MALLOC
**
This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mem_methods] structure. The argument specifies ** alternative low-level memory allocation routines to be used in place of ** the memory allocation routines built into SQLite.
** **
SQLITE_CONFIG_GETMALLOC
**
This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mem_methods] structure. The [sqlite3_mem_methods] ** structure is filled with the currently defined memory allocation routines. ** This option can be used to overload the default memory allocation ** routines with a wrapper that simulations memory allocation failure or ** tracks memory usage, for example.
** **
SQLITE_CONFIG_MEMSTATUS
**
This option takes single argument of type int, interpreted as a ** boolean, which enables or disables the collection of memory allocation ** statistics. When disabled, the following SQLite interfaces become ** non-operational: **
    **
  • [sqlite3_memory_used()] **
  • [sqlite3_memory_highwater()] **
  • [sqlite3_soft_heap_limit()] **
  • [sqlite3_status()] **
**
** **
SQLITE_CONFIG_SCRATCH
**
This option specifies a static memory buffer that SQLite can use for ** scratch memory. There are three arguments: A pointer to the memory, the ** size of each scratch buffer (sz), and the number of buffers (N). The sz ** argument must be a multiple of 16. The sz parameter should be a few bytes ** larger than the actual scratch space required due internal overhead. ** The first ** argument should point to an allocation of at least sz*N bytes of memory. ** SQLite will use no more than one scratch buffer at once per thread, so ** N should be set to the expected maximum number of threads. The sz ** parameter should be 6 times the size of the largest database page size. ** Scratch buffers are used as part of the btree balance operation. If ** The btree balancer needs additional memory beyond what is provided by ** scratch buffers or if no scratch buffer space is specified, then SQLite ** goes to [sqlite3_malloc()] to obtain the memory it needs.
** **
SQLITE_CONFIG_PAGECACHE
**
This option specifies a static memory buffer that SQLite can use for ** the database page cache with the default page cache implemenation. ** This configuration should not be used if an application-define page ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE option. ** There are three arguments to this option: A pointer to the ** memory, the size of each page buffer (sz), and the number of pages (N). ** The sz argument must be a power of two between 512 and 32768. The first ** argument should point to an allocation of at least sz*N bytes of memory. ** SQLite will use the memory provided by the first argument to satisfy its ** memory needs for the first N pages that it adds to cache. If additional ** page cache memory is needed beyond what is provided by this option, then ** SQLite goes to [sqlite3_malloc()] for the additional storage space. ** The implementation might use one or more of the N buffers to hold ** memory accounting information.
** **
SQLITE_CONFIG_HEAP
**
This option specifies a static memory buffer that SQLite will use ** for all of its dynamic memory allocation needs beyond those provided ** for by [SQLITE_CONFIG_SCRATCH] and [SQLITE_CONFIG_PAGECACHE]. ** There are three arguments: A pointer to the memory, the number of ** bytes in the memory buffer, and the minimum allocation size. If ** the first pointer (the memory pointer) is NULL, then SQLite reverts ** to using its default memory allocator (the system malloc() implementation), ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC]. If the ** memory pointer is not NULL and either [SQLITE_ENABLE_MEMSYS3] or ** [SQLITE_ENABLE_MEMSYS5] are defined, then the alternative memory ** allocator is engaged to handle all of SQLites memory allocation needs.
** **
SQLITE_CONFIG_MUTEX
**
This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mutex_methods] structure. The argument specifies ** alternative low-level mutex routines to be used in place ** the mutex routines built into SQLite.
** **
SQLITE_CONFIG_GETMUTEX
**
This option takes a single argument which is a pointer to an ** instance of the [sqlite3_mutex_methods] structure. The ** [sqlite3_mutex_methods] ** structure is filled with the currently defined mutex routines. ** This option can be used to overload the default mutex allocation ** routines with a wrapper used to track mutex usage for performance ** profiling or testing, for example.
** **
SQLITE_CONFIG_LOOKASIDE
**
This option takes two arguments that determine the default ** memory allcation lookaside optimization. The first argument is the ** size of each lookaside buffer slot and the second is the number of ** slots allocated to each database connection.
** **
SQLITE_CONFIG_PCACHE
**
This option takes a single argument which is a pointer to ** an [sqlite3_pcache_methods] object. This object specifies the interface ** to a custom page cache implementation. SQLite makes a copy of the ** object and uses it for page cache memory allocations.
** **
SQLITE_CONFIG_GETPCACHE
**
This option takes a single argument which is a pointer to an ** [sqlite3_pcache_methods] object. SQLite copies of the current ** page cache implementation into that object.
** **
*/ #define SQLITE_CONFIG_SINGLETHREAD 1 /* nil */ #define SQLITE_CONFIG_MULTITHREAD 2 /* nil */ #define SQLITE_CONFIG_SERIALIZED 3 /* nil */ #define SQLITE_CONFIG_MALLOC 4 /* sqlite3_mem_methods* */ #define SQLITE_CONFIG_GETMALLOC 5 /* sqlite3_mem_methods* */ #define SQLITE_CONFIG_SCRATCH 6 /* void*, int sz, int N */ #define SQLITE_CONFIG_PAGECACHE 7 /* void*, int sz, int N */ #define SQLITE_CONFIG_HEAP 8 /* void*, int nByte, int min */ #define SQLITE_CONFIG_MEMSTATUS 9 /* boolean */ #define SQLITE_CONFIG_MUTEX 10 /* sqlite3_mutex_methods* */ #define SQLITE_CONFIG_GETMUTEX 11 /* sqlite3_mutex_methods* */ /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ #define SQLITE_CONFIG_LOOKASIDE 13 /* int int */ #define SQLITE_CONFIG_PCACHE 14 /* sqlite3_pcache_methods* */ #define SQLITE_CONFIG_GETPCACHE 15 /* sqlite3_pcache_methods* */ /* ** CAPI3REF: Configuration Options {H10170} ** EXPERIMENTAL ** ** These constants are the available integer configuration options that ** can be passed as the second argument to the [sqlite3_db_config()] interface. ** ** New configuration options may be added in future releases of SQLite. ** Existing configuration options might be discontinued. Applications ** should check the return code from [sqlite3_db_config()] to make sure that ** the call worked. The [sqlite3_db_config()] interface will return a ** non-zero [error code] if a discontinued or unsupported configuration option ** is invoked. ** **
**
SQLITE_DBCONFIG_LOOKASIDE
**
This option takes three additional arguments that determine the ** [lookaside memory allocator] configuration for the [database connection]. ** The first argument (the third parameter to [sqlite3_db_config()] is a ** pointer to a memory buffer to use for lookaside memory. The first ** argument may be NULL in which case SQLite will allocate the lookaside ** buffer itself using [sqlite3_malloc()]. The second argument is the ** size of each lookaside buffer slot and the third argument is the number of ** slots. The size of the buffer in the first argument must be greater than ** or equal to the product of the second and third arguments.
** **
*/ #define SQLITE_DBCONFIG_LOOKASIDE 1001 /* void* int int */ /* ** CAPI3REF: Enable Or Disable Extended Result Codes {H12200} ** ** The sqlite3_extended_result_codes() routine enables or disables the ** [extended result codes] feature of SQLite. The extended result ** codes are disabled by default for historical compatibility considerations. ** ** Requirements: ** [H12201] [H12202] */ int sqlite3_extended_result_codes(sqlite3*, int onoff); /* ** CAPI3REF: Last Insert Rowid {H12220} ** ** Each entry in an SQLite table has a unique 64-bit signed ** integer key called the [ROWID | "rowid"]. The rowid is always available ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those ** names are not also used by explicitly declared columns. If ** the table has a column of type [INTEGER PRIMARY KEY] then that column ** is another alias for the rowid. ** ** This routine returns the [rowid] of the most recent ** successful [INSERT] into the database from the [database connection] ** in the first argument. If no successful [INSERT]s ** have ever occurred on that database connection, zero is returned. ** ** If an [INSERT] occurs within a trigger, then the [rowid] of the inserted ** row is returned by this routine as long as the trigger is running. ** But once the trigger terminates, the value returned by this routine ** reverts to the last value inserted before the trigger fired. ** ** An [INSERT] that fails due to a constraint violation is not a ** successful [INSERT] and does not change the value returned by this ** routine. Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK, ** and INSERT OR ABORT make no changes to the return value of this ** routine when their insertion fails. When INSERT OR REPLACE ** encounters a constraint violation, it does not fail. The ** INSERT continues to completion after deleting rows that caused ** the constraint problem so INSERT OR REPLACE will always change ** the return value of this interface. ** ** For the purposes of this routine, an [INSERT] is considered to ** be successful even if it is subsequently rolled back. ** ** Requirements: ** [H12221] [H12223] ** ** If a separate thread performs a new [INSERT] on the same ** database connection while the [sqlite3_last_insert_rowid()] ** function is running and thus changes the last insert [rowid], ** then the value returned by [sqlite3_last_insert_rowid()] is ** unpredictable and might not equal either the old or the new ** last insert [rowid]. */ sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*); /* ** CAPI3REF: Count The Number Of Rows Modified {H12240} ** ** This function returns the number of database rows that were changed ** or inserted or deleted by the most recently completed SQL statement ** on the [database connection] specified by the first parameter. ** Only changes that are directly specified by the [INSERT], [UPDATE], ** or [DELETE] statement are counted. Auxiliary changes caused by ** triggers are not counted. Use the [sqlite3_total_changes()] function ** to find the total number of changes including changes caused by triggers. ** ** A "row change" is a change to a single row of a single table ** caused by an INSERT, DELETE, or UPDATE statement. Rows that ** are changed as side effects of REPLACE constraint resolution, ** rollback, ABORT processing, DROP TABLE, or by any other ** mechanisms do not count as direct row changes. ** ** A "trigger context" is a scope of execution that begins and ** ends with the script of a trigger. Most SQL statements are ** evaluated outside of any trigger. This is the "top level" ** trigger context. If a trigger fires from the top level, a ** new trigger context is entered for the duration of that one ** trigger. Subtriggers create subcontexts for their duration. ** ** Calling [sqlite3_exec()] or [sqlite3_step()] recursively does ** not create a new trigger context. ** ** This function returns the number of direct row changes in the ** most recent INSERT, UPDATE, or DELETE statement within the same ** trigger context. ** ** Thus, when called from the top level, this function returns the ** number of changes in the most recent INSERT, UPDATE, or DELETE ** that also occurred at the top level. Within the body of a trigger, ** the sqlite3_changes() interface can be called to find the number of ** changes in the most recently completed INSERT, UPDATE, or DELETE ** statement within the body of the same trigger. ** However, the number returned does not include changes ** caused by subtriggers since those have their own context. ** ** SQLite implements the command "DELETE FROM table" without a WHERE clause ** by dropping and recreating the table. Doing so is much faster than going ** through and deleting individual elements from the table. Because of this ** optimization, the deletions in "DELETE FROM table" are not row changes and ** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()] ** functions, regardless of the number of elements that were originally ** in the table. To get an accurate count of the number of rows deleted, use ** "DELETE FROM table WHERE 1" instead. Or recompile using the ** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the ** optimization on all queries. ** ** Requirements: ** [H12241] [H12243] ** ** If a separate thread makes changes on the same database connection ** while [sqlite3_changes()] is running then the value returned ** is unpredictable and not meaningful. */ int sqlite3_changes(sqlite3*); /* ** CAPI3REF: Total Number Of Rows Modified {H12260} ** ** This function returns the number of row changes caused by INSERT, ** UPDATE or DELETE statements since the [database connection] was opened. ** The count includes all changes from all trigger contexts. However, ** the count does not include changes used to implement REPLACE constraints, ** do rollbacks or ABORT processing, or DROP table processing. ** The changes are counted as soon as the statement that makes them is ** completed (when the statement handle is passed to [sqlite3_reset()] or ** [sqlite3_finalize()]). ** ** SQLite implements the command "DELETE FROM table" without a WHERE clause ** by dropping and recreating the table. (This is much faster than going ** through and deleting individual elements from the table.) Because of this ** optimization, the deletions in "DELETE FROM table" are not row changes and ** will not be counted by the sqlite3_changes() or [sqlite3_total_changes()] ** functions, regardless of the number of elements that were originally ** in the table. To get an accurate count of the number of rows deleted, use ** "DELETE FROM table WHERE 1" instead. Or recompile using the ** [SQLITE_OMIT_TRUNCATE_OPTIMIZATION] compile-time option to disable the ** optimization on all queries. ** ** See also the [sqlite3_changes()] interface. ** ** Requirements: ** [H12261] [H12263] ** ** If a separate thread makes changes on the same database connection ** while [sqlite3_total_changes()] is running then the value ** returned is unpredictable and not meaningful. */ int sqlite3_total_changes(sqlite3*); /* ** CAPI3REF: Interrupt A Long-Running Query {H12270} ** ** This function causes any pending database operation to abort and ** return at its earliest opportunity. This routine is typically ** called in response to a user action such as pressing "Cancel" ** or Ctrl-C where the user wants a long query operation to halt ** immediately. ** ** It is safe to call this routine from a thread different from the ** thread that is currently running the database operation. But it ** is not safe to call this routine with a [database connection] that ** is closed or might close before sqlite3_interrupt() returns. ** ** If an SQL operation is very nearly finished at the time when ** sqlite3_interrupt() is called, then it might not have an opportunity ** to be interrupted and might continue to completion. ** ** An SQL operation that is interrupted will return [SQLITE_INTERRUPT]. ** If the interrupted SQL operation is an INSERT, UPDATE, or DELETE ** that is inside an explicit transaction, then the entire transaction ** will be rolled back automatically. ** ** A call to sqlite3_interrupt() has no effect on SQL statements ** that are started after sqlite3_interrupt() returns. ** ** Requirements: ** [H12271] [H12272] ** ** If the database connection closes while [sqlite3_interrupt()] ** is running then bad things will likely happen. */ void sqlite3_interrupt(sqlite3*); /* ** CAPI3REF: Determine If An SQL Statement Is Complete {H10510} ** ** These routines are useful for command-line input to determine if the ** currently entered text seems to form complete a SQL statement or ** if additional input is needed before sending the text into ** SQLite for parsing. These routines return true if the input string ** appears to be a complete SQL statement. A statement is judged to be ** complete if it ends with a semicolon token and is not a fragment of a ** CREATE TRIGGER statement. Semicolons that are embedded within ** string literals or quoted identifier names or comments are not ** independent tokens (they are part of the token in which they are ** embedded) and thus do not count as a statement terminator. ** ** These routines do not parse the SQL statements thus ** will not detect syntactically incorrect SQL. ** ** Requirements: [H10511] [H10512] ** ** The input to [sqlite3_complete()] must be a zero-terminated ** UTF-8 string. ** ** The input to [sqlite3_complete16()] must be a zero-terminated ** UTF-16 string in native byte order. */ int sqlite3_complete(const char *sql); int sqlite3_complete16(const void *sql); /* ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors {H12310} ** ** This routine sets a callback function that might be invoked whenever ** an attempt is made to open a database table that another thread ** or process has locked. ** ** If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] ** is returned immediately upon encountering the lock. If the busy callback ** is not NULL, then the callback will be invoked with two arguments. ** ** The first argument to the handler is a copy of the void* pointer which ** is the third argument to sqlite3_busy_handler(). The second argument to ** the handler callback is the number of times that the busy handler has ** been invoked for this locking event. If the ** busy callback returns 0, then no additional attempts are made to ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned. ** If the callback returns non-zero, then another attempt ** is made to open the database for reading and the cycle repeats. ** ** The presence of a busy handler does not guarantee that it will be invoked ** when there is lock contention. If SQLite determines that invoking the busy ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY] ** or [SQLITE_IOERR_BLOCKED] instead of invoking the busy handler. ** Consider a scenario where one process is holding a read lock that ** it is trying to promote to a reserved lock and ** a second process is holding a reserved lock that it is trying ** to promote to an exclusive lock. The first process cannot proceed ** because it is blocked by the second and the second process cannot ** proceed because it is blocked by the first. If both processes ** invoke the busy handlers, neither will make any progress. Therefore, ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this ** will induce the first process to release its read lock and allow ** the second process to proceed. ** ** The default busy callback is NULL. ** ** The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED] ** when SQLite is in the middle of a large transaction where all the ** changes will not fit into the in-memory cache. SQLite will ** already hold a RESERVED lock on the database file, but it needs ** to promote this lock to EXCLUSIVE so that it can spill cache ** pages into the database file without harm to concurrent ** readers. If it is unable to promote the lock, then the in-memory ** cache will be left in an inconsistent state and so the error ** code is promoted from the relatively benign [SQLITE_BUSY] to ** the more severe [SQLITE_IOERR_BLOCKED]. This error code promotion ** forces an automatic rollback of the changes. See the ** ** CorruptionFollowingBusyError wiki page for a discussion of why ** this is important. ** ** There can only be a single busy handler defined for each ** [database connection]. Setting a new busy handler clears any ** previously set handler. Note that calling [sqlite3_busy_timeout()] ** will also set or clear the busy handler. ** ** The busy callback should not take any actions which modify the ** database connection that invoked the busy handler. Any such actions ** result in undefined behavior. ** ** Requirements: ** [H12311] [H12312] [H12314] [H12316] [H12318] ** ** A busy handler must not close the database connection ** or [prepared statement] that invoked the busy handler. */ int sqlite3_busy_handler(sqlite3*, int(*)(void*,int), void*); /* ** CAPI3REF: Set A Busy Timeout {H12340} ** ** This routine sets a [sqlite3_busy_handler | busy handler] that sleeps ** for a specified amount of time when a table is locked. The handler ** will sleep multiple times until at least "ms" milliseconds of sleeping ** have accumulated. {H12343} After "ms" milliseconds of sleeping, ** the handler returns 0 which causes [sqlite3_step()] to return ** [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]. ** ** Calling this routine with an argument less than or equal to zero ** turns off all busy handlers. ** ** There can only be a single busy handler for a particular ** [database connection] any any given moment. If another busy handler ** was defined (using [sqlite3_busy_handler()]) prior to calling ** this routine, that other busy handler is cleared. ** ** Requirements: ** [H12341] [H12343] [H12344] */ int sqlite3_busy_timeout(sqlite3*, int ms); /* ** CAPI3REF: Convenience Routines For Running Queries {H12370} ** ** Definition: A result table is memory data structure created by the ** [sqlite3_get_table()] interface. A result table records the ** complete query results from one or more queries. ** ** The table conceptually has a number of rows and columns. But ** these numbers are not part of the result table itself. These ** numbers are obtained separately. Let N be the number of rows ** and M be the number of columns. ** ** A result table is an array of pointers to zero-terminated UTF-8 strings. ** There are (N+1)*M elements in the array. The first M pointers point ** to zero-terminated strings that contain the names of the columns. ** The remaining entries all point to query results. NULL values result ** in NULL pointers. All other values are in their UTF-8 zero-terminated ** string representation as returned by [sqlite3_column_text()]. ** ** A result table might consist of one or more memory allocations. ** It is not safe to pass a result table directly to [sqlite3_free()]. ** A result table should be deallocated using [sqlite3_free_table()]. ** ** As an example of the result table format, suppose a query result ** is as follows: ** ** 
**        Name        | Age
**        -----------------------
**        Alice       | 43
**        Bob         | 28
**        Cindy       | 21
**
** ** There are two column (M==2) and three rows (N==3). Thus the ** result table has 8 entries. Suppose the result table is stored ** in an array names azResult. Then azResult holds this content: ** ** 
**        azResult[0] = "Name";
**        azResult[1] = "Age";
**        azResult[2] = "Alice";
**        azResult[3] = "43";
**        azResult[4] = "Bob";
**        azResult[5] = "28";
**        azResult[6] = "Cindy";
**        azResult[7] = "21";
**
** ** The sqlite3_get_table() function evaluates one or more ** semicolon-separated SQL statements in the zero-terminated UTF-8 ** string of its 2nd parameter. It returns a result table to the ** pointer given in its 3rd parameter. ** ** After the calling function has finished using the result, it should ** pass the pointer to the result table to sqlite3_free_table() in order to ** release the memory that was malloced. Because of the way the ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling ** function must not try to call [sqlite3_free()] directly. Only ** [sqlite3_free_table()] is able to release the memory properly and safely. ** ** The sqlite3_get_table() interface is implemented as a wrapper around ** [sqlite3_exec()]. The sqlite3_get_table() routine does not have access ** to any internal data structures of SQLite. It uses only the public ** interface defined here. As a consequence, errors that occur in the ** wrapper layer outside of the internal [sqlite3_exec()] call are not ** reflected in subsequent calls to [sqlite3_errcode()] or [sqlite3_errmsg()]. ** ** Requirements: ** [H12371] [H12373] [H12374] [H12376] [H12379] [H12382] */ int sqlite3_get_table( sqlite3 *db, /* An open database */ const char *zSql, /* SQL to be evaluated */ char ***pazResult, /* Results of the query */ int *pnRow, /* Number of result rows written here */ int *pnColumn, /* Number of result columns written here */ char **pzErrmsg /* Error msg written here */ ); void sqlite3_free_table(char **result); /* ** CAPI3REF: Formatted String Printing Functions {H17400} ** ** These routines are workalikes of the "printf()" family of functions ** from the standard C library. ** ** The sqlite3_mprintf() and sqlite3_vmprintf() routines write their ** results into memory obtained from [sqlite3_malloc()]. ** The strings returned by these two routines should be ** released by [sqlite3_free()]. Both routines return a ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough ** memory to hold the resulting string. ** ** In sqlite3_snprintf() routine is similar to "snprintf()" from ** the standard C library. The result is written into the ** buffer supplied as the second parameter whose size is given by ** the first parameter. Note that the order of the ** first two parameters is reversed from snprintf(). This is an ** historical accident that cannot be fixed without breaking ** backwards compatibility. Note also that sqlite3_snprintf() ** returns a pointer to its buffer instead of the number of ** characters actually written into the buffer. We admit that ** the number of characters written would be a more useful return ** value but we cannot change the implementation of sqlite3_snprintf() ** now without breaking compatibility. ** ** As long as the buffer size is greater than zero, sqlite3_snprintf() ** guarantees that the buffer is always zero-terminated. The first ** parameter "n" is the total size of the buffer, including space for ** the zero terminator. So the longest string that can be completely ** written will be n-1 characters. ** ** These routines all implement some additional formatting ** options that are useful for constructing SQL statements. ** All of the usual printf() formatting options apply. In addition, there ** is are "%q", "%Q", and "%z" options. ** ** The %q option works like %s in that it substitutes a null-terminated ** string from the argument list. But %q also doubles every '\'' character. ** %q is designed for use inside a string literal. By doubling each '\'' ** character it escapes that character and allows it to be inserted into ** the string. ** ** For example, assume the string variable zText contains text as follows: ** ** 
**  char *zText = "It's a happy day!";
**
** ** One can use this text in an SQL statement as follows: ** ** 
**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
**  sqlite3_exec(db, zSQL, 0, 0, 0);
**  sqlite3_free(zSQL);
**
** ** Because the %q format string is used, the '\'' character in zText ** is escaped and the SQL generated is as follows: ** ** 
**  INSERT INTO table1 VALUES('It''s a happy day!')
**
** ** This is correct. Had we used %s instead of %q, the generated SQL ** would have looked like this: ** ** 
**  INSERT INTO table1 VALUES('It's a happy day!');
**
** ** This second example is an SQL syntax error. As a general rule you should ** always use %q instead of %s when inserting text into a string literal. ** ** The %Q option works like %q except it also adds single quotes around ** the outside of the total string. Additionally, if the parameter in the ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without ** single quotes) in place of the %Q option. So, for example, one could say: ** ** 
**  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
**  sqlite3_exec(db, zSQL, 0, 0, 0);
**  sqlite3_free(zSQL);
**
** ** The code above will render a correct SQL statement in the zSQL ** variable even if the zText variable is a NULL pointer. ** ** The "%z" formatting option works exactly like "%s" with the ** addition that after the string has been read and copied into ** the result, [sqlite3_free()] is called on the input string. {END} ** ** Requirements: ** [H17403] [H17406] [H17407] */ char *sqlite3_mprintf(const char*,...); char *sqlite3_vmprintf(const char*, va_list); char *sqlite3_snprintf(int,char*,const char*, ...); /* ** CAPI3REF: Memory Allocation Subsystem {H17300} ** ** The SQLite core uses these three routines for all of its own ** internal memory allocation needs. "Core" in the previous sentence ** does not include operating-system specific VFS implementation. The ** Windows VFS uses native malloc() and free() for some operations. ** ** The sqlite3_malloc() routine returns a pointer to a block ** of memory at least N bytes in length, where N is the parameter. ** If sqlite3_malloc() is unable to obtain sufficient free ** memory, it returns a NULL pointer. If the parameter N to ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns ** a NULL pointer. ** ** Calling sqlite3_free() with a pointer previously returned ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so ** that it might be reused. The sqlite3_free() routine is ** a no-op if is called with a NULL pointer. Passing a NULL pointer ** to sqlite3_free() is harmless. After being freed, memory ** should neither be read nor written. Even reading previously freed ** memory might result in a segmentation fault or other severe error. ** Memory corruption, a segmentation fault, or other severe error ** might result if sqlite3_free() is called with a non-NULL pointer that ** was not obtained from sqlite3_malloc() or sqlite3_realloc(). ** ** The sqlite3_realloc() interface attempts to resize a ** prior memory allocation to be at least N bytes, where N is the ** second parameter. The memory allocation to be resized is the first ** parameter. If the first parameter to sqlite3_realloc() ** is a NULL pointer then its behavior is identical to calling ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc(). ** If the second parameter to sqlite3_realloc() is zero or ** negative then the behavior is exactly the same as calling ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc(). ** sqlite3_realloc() returns a pointer to a memory allocation ** of at least N bytes in size or NULL if sufficient memory is unavailable. ** If M is the size of the prior allocation, then min(N,M) bytes ** of the prior allocation are copied into the beginning of buffer returned ** by sqlite3_realloc() and the prior allocation is freed. ** If sqlite3_realloc() returns NULL, then the prior allocation ** is not freed. ** ** The memory returned by sqlite3_malloc() and sqlite3_realloc() ** is always aligned to at least an 8 byte boundary. {END} ** ** The default implementation of the memory allocation subsystem uses ** the malloc(), realloc() and free() provided by the standard C library. ** {H17382} However, if SQLite is compiled with the ** SQLITE_MEMORY_SIZE=NNN C preprocessor macro (where NNN ** is an integer), then SQLite create a static array of at least ** NNN bytes in size and uses that array for all of its dynamic ** memory allocation needs. {END} Additional memory allocator options ** may be added in future releases. ** ** In SQLite version 3.5.0 and 3.5.1, it was possible to define ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in ** implementation of these routines to be omitted. That capability ** is no longer provided. Only built-in memory allocators can be used. ** ** The Windows OS interface layer calls ** the system malloc() and free() directly when converting ** filenames between the UTF-8 encoding used by SQLite ** and whatever filename encoding is used by the particular Windows ** installation. Memory allocation errors are detected, but ** they are reported back as [SQLITE_CANTOPEN] or ** [SQLITE_IOERR] rather than [SQLITE_NOMEM]. ** ** Requirements: ** [H17303] [H17304] [H17305] [H17306] [H17310] [H17312] [H17315] [H17318] ** [H17321] [H17322] [H17323] ** ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()] ** must be either NULL or else pointers obtained from a prior ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have ** not yet been released. ** ** The application must not read or write any part of ** a block of memory after it has been released using ** [sqlite3_free()] or [sqlite3_realloc()]. */ void *sqlite3_malloc(int); void *sqlite3_realloc(void*, int); void sqlite3_free(void*); /* ** CAPI3REF: Memory Allocator Statistics {H17370} ** ** SQLite provides these two interfaces for reporting on the status ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()] ** routines, which form the built-in memory allocation subsystem. ** ** Requirements: ** [H17371] [H17373] [H17374] [H17375] */ sqlite3_int64 sqlite3_memory_used(void); sqlite3_int64 sqlite3_memory_highwater(int resetFlag); /* ** CAPI3REF: Pseudo-Random Number Generator {H17390} ** ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to ** select random [ROWID | ROWIDs] when inserting new records into a table that ** already uses the largest possible [ROWID]. The PRNG is also used for ** the build-in random() and randomblob() SQL functions. This interface allows ** applications to access the same PRNG for other purposes. ** ** A call to this routine stores N bytes of randomness into buffer P. ** ** The first time this routine is invoked (either internally or by ** the application) the PRNG is seeded using randomness obtained ** from the xRandomness method of the default [sqlite3_vfs] object. ** On all subsequent invocations, the pseudo-randomness is generated ** internally and without recourse to the [sqlite3_vfs] xRandomness ** method. ** ** Requirements: ** [H17392] */ void sqlite3_randomness(int N, void *P); /* ** CAPI3REF: Compile-Time Authorization Callbacks {H12500} ** ** This routine registers a authorizer callback with a particular ** [database connection], supplied in the first argument. ** The authorizer callback is invoked as SQL statements are being compiled ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()], ** [sqlite3_prepare16()] and [sqlite3_prepare16_v2()]. At various ** points during the compilation process, as logic is being created ** to perform various actions, the authorizer callback is invoked to ** see if those actions are allowed. The authorizer callback should ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the ** specific action but allow the SQL statement to continue to be ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be ** rejected with an error. If the authorizer callback returns ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY] ** then the [sqlite3_prepare_v2()] or equivalent call that triggered ** the authorizer will fail with an error message. ** ** When the callback returns [SQLITE_OK], that means the operation ** requested is ok. When the callback returns [SQLITE_DENY], the ** [sqlite3_prepare_v2()] or equivalent call that triggered the ** authorizer will fail with an error message explaining that ** access is denied. If the authorizer code is [SQLITE_READ] ** and the callback returns [SQLITE_IGNORE] then the ** [prepared statement] statement is constructed to substitute ** a NULL value in place of the table column that would have ** been read if [SQLITE_OK] had been returned. The [SQLITE_IGNORE] ** return can be used to deny an untrusted user access to individual ** columns of a table. ** ** The first parameter to the authorizer callback is a copy of the third ** parameter to the sqlite3_set_authorizer() interface. The second parameter ** to the callback is an integer [SQLITE_COPY | action code] that specifies ** the particular action to be authorized. The third through sixth parameters ** to the callback are zero-terminated strings that contain additional ** details about the action to be authorized. ** ** An authorizer is used when [sqlite3_prepare | preparing] ** SQL statements from an untrusted source, to ensure that the SQL statements ** do not try to access data they are not allowed to see, or that they do not ** try to execute malicious statements that damage the database. For ** example, an application may allow a user to enter arbitrary ** SQL queries for evaluation by a database. But the application does ** not want the user to be able to make arbitrary changes to the ** database. An authorizer could then be put in place while the ** user-entered SQL is being [sqlite3_prepare | prepared] that ** disallows everything except [SELECT] statements. ** ** Applications that need to process SQL from untrusted sources ** might also consider lowering resource limits using [sqlite3_limit()] ** and limiting database size using the [max_page_count] [PRAGMA] ** in addition to using an authorizer. ** ** Only a single authorizer can be in place on a database connection ** at a time. Each call to sqlite3_set_authorizer overrides the ** previous call. Disable the authorizer by installing a NULL callback. ** The authorizer is disabled by default. ** ** The authorizer callback must not do anything that will modify ** the database connection that invoked the authorizer callback. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** When [sqlite3_prepare_v2()] is used to prepare a statement, the ** statement might be reprepared during [sqlite3_step()] due to a ** schema change. Hence, the application should ensure that the ** correct authorizer callback remains in place during the [sqlite3_step()]. ** ** Note that the authorizer callback is invoked only during ** [sqlite3_prepare()] or its variants. Authorization is not ** performed during statement evaluation in [sqlite3_step()]. ** ** Requirements: ** [H12501] [H12502] [H12503] [H12504] [H12505] [H12506] [H12507] [H12510] ** [H12511] [H12512] [H12520] [H12521] [H12522] */ int sqlite3_set_authorizer( sqlite3*, int (*xAuth)(void*,int,const char*,const char*,const char*,const char*), void *pUserData ); /* ** CAPI3REF: Authorizer Return Codes {H12590} ** ** The [sqlite3_set_authorizer | authorizer callback function] must ** return either [SQLITE_OK] or one of these two constants in order ** to signal SQLite whether or not the action is permitted. See the ** [sqlite3_set_authorizer | authorizer documentation] for additional ** information. */ #define SQLITE_DENY 1 /* Abort the SQL statement with an error */ #define SQLITE_IGNORE 2 /* Don't allow access, but don't generate an error */ /* ** CAPI3REF: Authorizer Action Codes {H12550} ** ** The [sqlite3_set_authorizer()] interface registers a callback function ** that is invoked to authorize certain SQL statement actions. The ** second parameter to the callback is an integer code that specifies ** what action is being authorized. These are the integer action codes that ** the authorizer callback may be passed. ** ** These action code values signify what kind of operation is to be ** authorized. The 3rd and 4th parameters to the authorization ** callback function will be parameters or NULL depending on which of these ** codes is used as the second parameter. The 5th parameter to the ** authorizer callback is the name of the database ("main", "temp", ** etc.) if applicable. The 6th parameter to the authorizer callback ** is the name of the inner-most trigger or view that is responsible for ** the access attempt or NULL if this access attempt is directly from ** top-level SQL code. ** ** Requirements: ** [H12551] [H12552] [H12553] [H12554] */ /******************************************* 3rd ************ 4th ***********/ #define SQLITE_CREATE_INDEX 1 /* Index Name Table Name */ #define SQLITE_CREATE_TABLE 2 /* Table Name NULL */ #define SQLITE_CREATE_TEMP_INDEX 3 /* Index Name Table Name */ #define SQLITE_CREATE_TEMP_TABLE 4 /* Table Name NULL */ #define SQLITE_CREATE_TEMP_TRIGGER 5 /* Trigger Name Table Name */ #define SQLITE_CREATE_TEMP_VIEW 6 /* View Name NULL */ #define SQLITE_CREATE_TRIGGER 7 /* Trigger Name Table Name */ #define SQLITE_CREATE_VIEW 8 /* View Name NULL */ #define SQLITE_DELETE 9 /* Table Name NULL */ #define SQLITE_DROP_INDEX 10 /* Index Name Table Name */ #define SQLITE_DROP_TABLE 11 /* Table Name NULL */ #define SQLITE_DROP_TEMP_INDEX 12 /* Index Name Table Name */ #define SQLITE_DROP_TEMP_TABLE 13 /* Table Name NULL */ #define SQLITE_DROP_TEMP_TRIGGER 14 /* Trigger Name Table Name */ #define SQLITE_DROP_TEMP_VIEW 15 /* View Name NULL */ #define SQLITE_DROP_TRIGGER 16 /* Trigger Name Table Name */ #define SQLITE_DROP_VIEW 17 /* View Name NULL */ #define SQLITE_INSERT 18 /* Table Name NULL */ #define SQLITE_PRAGMA 19 /* Pragma Name 1st arg or NULL */ #define SQLITE_READ 20 /* Table Name Column Name */ #define SQLITE_SELECT 21 /* NULL NULL */ #define SQLITE_TRANSACTION 22 /* Operation NULL */ #define SQLITE_UPDATE 23 /* Table Name Column Name */ #define SQLITE_ATTACH 24 /* Filename NULL */ #define SQLITE_DETACH 25 /* Database Name NULL */ #define SQLITE_ALTER_TABLE 26 /* Database Name Table Name */ #define SQLITE_REINDEX 27 /* Index Name NULL */ #define SQLITE_ANALYZE 28 /* Table Name NULL */ #define SQLITE_CREATE_VTABLE 29 /* Table Name Module Name */ #define SQLITE_DROP_VTABLE 30 /* Table Name Module Name */ #define SQLITE_FUNCTION 31 /* NULL Function Name */ #define SQLITE_SAVEPOINT 32 /* Operation Savepoint Name */ #define SQLITE_COPY 0 /* No longer used */ /* ** CAPI3REF: Tracing And Profiling Functions {H12280} ** EXPERIMENTAL ** ** These routines register callback functions that can be used for ** tracing and profiling the execution of SQL statements. ** ** The callback function registered by sqlite3_trace() is invoked at ** various times when an SQL statement is being run by [sqlite3_step()]. ** The callback returns a UTF-8 rendering of the SQL statement text ** as the statement first begins executing. Additional callbacks occur ** as each triggered subprogram is entered. The callbacks for triggers ** contain a UTF-8 SQL comment that identifies the trigger. ** ** The callback function registered by sqlite3_profile() is invoked ** as each SQL statement finishes. The profile callback contains ** the original statement text and an estimate of wall-clock time ** of how long that statement took to run. ** ** Requirements: ** [H12281] [H12282] [H12283] [H12284] [H12285] [H12287] [H12288] [H12289] ** [H12290] */ SQLITE_EXPERIMENTAL void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*); SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*, void(*xProfile)(void*,const char*,sqlite3_uint64), void*); /* ** CAPI3REF: Query Progress Callbacks {H12910} ** ** This routine configures a callback function - the ** progress callback - that is invoked periodically during long ** running calls to [sqlite3_exec()], [sqlite3_step()] and ** [sqlite3_get_table()]. An example use for this ** interface is to keep a GUI updated during a large query. ** ** If the progress callback returns non-zero, the operation is ** interrupted. This feature can be used to implement a ** "Cancel" button on a GUI progress dialog box. ** ** The progress handler must not do anything that will modify ** the database connection that invoked the progress handler. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** Requirements: ** [H12911] [H12912] [H12913] [H12914] [H12915] [H12916] [H12917] [H12918] ** */ void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*); /* ** CAPI3REF: Opening A New Database Connection {H12700} ** ** These routines open an SQLite database file whose name is given by the ** filename argument. The filename argument is interpreted as UTF-8 for ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte ** order for sqlite3_open16(). A [database connection] handle is usually ** returned in *ppDb, even if an error occurs. The only exception is that ** if SQLite is unable to allocate memory to hold the [sqlite3] object, ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3] ** object. If the database is opened (and/or created) successfully, then ** [SQLITE_OK] is returned. Otherwise an [error code] is returned. The ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain ** an English language description of the error. ** ** The default encoding for the database will be UTF-8 if ** sqlite3_open() or sqlite3_open_v2() is called and ** UTF-16 in the native byte order if sqlite3_open16() is used. ** ** Whether or not an error occurs when it is opened, resources ** associated with the [database connection] handle should be released by ** passing it to [sqlite3_close()] when it is no longer required. ** ** The sqlite3_open_v2() interface works like sqlite3_open() ** except that it accepts two additional parameters for additional control ** over the new database connection. The flags parameter can take one of ** the following three values, optionally combined with the ** [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags: ** **
**
[SQLITE_OPEN_READONLY]
**
The database is opened in read-only mode. If the database does not ** already exist, an error is returned.
** **
[SQLITE_OPEN_READWRITE]
**
The database is opened for reading and writing if possible, or reading ** only if the file is write protected by the operating system. In either ** case the database must already exist, otherwise an error is returned.
** **
[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]
**
The database is opened for reading and writing, and is creates it if ** it does not already exist. This is the behavior that is always used for ** sqlite3_open() and sqlite3_open16().
**
** ** If the 3rd parameter to sqlite3_open_v2() is not one of the ** combinations shown above or one of the combinations shown above combined ** with the [SQLITE_OPEN_NOMUTEX] or [SQLITE_OPEN_FULLMUTEX] flags, ** then the behavior is undefined. ** ** If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection ** opens in the multi-thread [threading mode] as long as the single-thread ** mode has not been set at compile-time or start-time. If the ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens ** in the serialized [threading mode] unless single-thread was ** previously selected at compile-time or start-time. ** ** If the filename is ":memory:", then a private, temporary in-memory database ** is created for the connection. This in-memory database will vanish when ** the database connection is closed. Future versions of SQLite might ** make use of additional special filenames that begin with the ":" character. ** It is recommended that when a database filename actually does begin with ** a ":" character you should prefix the filename with a pathname such as ** "./" to avoid ambiguity. ** ** If the filename is an empty string, then a private, temporary ** on-disk database will be created. This private database will be ** automatically deleted as soon as the database connection is closed. ** ** The fourth parameter to sqlite3_open_v2() is the name of the ** [sqlite3_vfs] object that defines the operating system interface that ** the new database connection should use. If the fourth parameter is ** a NULL pointer then the default [sqlite3_vfs] object is used. ** ** Note to Windows users: The encoding used for the filename argument ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever ** codepage is currently defined. Filenames containing international ** characters must be converted to UTF-8 prior to passing them into ** sqlite3_open() or sqlite3_open_v2(). ** ** Requirements: ** [H12701] [H12702] [H12703] [H12704] [H12706] [H12707] [H12709] [H12711] ** [H12712] [H12713] [H12714] [H12717] [H12719] [H12721] [H12723] */ int sqlite3_open( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb /* OUT: SQLite db handle */ ); int sqlite3_open16( const void *filename, /* Database filename (UTF-16) */ sqlite3 **ppDb /* OUT: SQLite db handle */ ); int sqlite3_open_v2( const char *filename, /* Database filename (UTF-8) */ sqlite3 **ppDb, /* OUT: SQLite db handle */ int flags, /* Flags */ const char *zVfs /* Name of VFS module to use */ ); /* ** CAPI3REF: Error Codes And Messages {H12800} ** ** The sqlite3_errcode() interface returns the numeric [result code] or ** [extended result code] for the most recent failed sqlite3_* API call ** associated with a [database connection]. If a prior API call failed ** but the most recent API call succeeded, the return value from ** sqlite3_errcode() is undefined. The sqlite3_extended_errcode() ** interface is the same except that it always returns the ** [extended result code] even when extended result codes are ** disabled. ** ** The sqlite3_errmsg() and sqlite3_errmsg16() return English-language ** text that describes the error, as either UTF-8 or UTF-16 respectively. ** Memory to hold the error message string is managed internally. ** The application does not need to worry about freeing the result. ** However, the error string might be overwritten or deallocated by ** subsequent calls to other SQLite interface functions. ** ** When the serialized [threading mode] is in use, it might be the ** case that a second error occurs on a separate thread in between ** the time of the first error and the call to these interfaces. ** When that happens, the second error will be reported since these ** interfaces always report the most recent result. To avoid ** this, each thread can obtain exclusive use of the [database connection] D ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after ** all calls to the interfaces listed here are completed. ** ** If an interface fails with SQLITE_MISUSE, that means the interface ** was invoked incorrectly by the application. In that case, the ** error code and message may or may not be set. ** ** Requirements: ** [H12801] [H12802] [H12803] [H12807] [H12808] [H12809] */ int sqlite3_errcode(sqlite3 *db); int sqlite3_extended_errcode(sqlite3 *db); const char *sqlite3_errmsg(sqlite3*); const void *sqlite3_errmsg16(sqlite3*); /* ** CAPI3REF: SQL Statement Object {H13000} ** KEYWORDS: {prepared statement} {prepared statements} ** ** An instance of this object represents a single SQL statement. ** This object is variously known as a "prepared statement" or a ** "compiled SQL statement" or simply as a "statement". ** ** The life of a statement object goes something like this: ** **
    **
  1. Create the object using [sqlite3_prepare_v2()] or a related ** function. **
  2. Bind values to [host parameters] using the sqlite3_bind_*() ** interfaces. **
  3. Run the SQL by calling [sqlite3_step()] one or more times. **
  4. Reset the statement using [sqlite3_reset()] then go back ** to step 2. Do this zero or more times. **
  5. Destroy the object using [sqlite3_finalize()]. **
** ** Refer to documentation on individual methods above for additional ** information. */ typedef struct sqlite3_stmt sqlite3_stmt; /* ** CAPI3REF: Run-time Limits {H12760} ** ** This interface allows the size of various constructs to be limited ** on a connection by connection basis. The first parameter is the ** [database connection] whose limit is to be set or queried. The ** second parameter is one of the [limit categories] that define a ** class of constructs to be size limited. The third parameter is the ** new limit for that construct. The function returns the old limit. ** ** If the new limit is a negative number, the limit is unchanged. ** For the limit category of SQLITE_LIMIT_XYZ there is a ** [limits | hard upper bound] ** set by a compile-time C preprocessor macro named ** [limits | SQLITE_MAX_XYZ]. ** (The "_LIMIT_" in the name is changed to "_MAX_".) ** Attempts to increase a limit above its hard upper bound are ** silently truncated to the hard upper limit. ** ** Run time limits are intended for use in applications that manage ** both their own internal database and also databases that are controlled ** by untrusted external sources. An example application might be a ** web browser that has its own databases for storing history and ** separate databases controlled by JavaScript applications downloaded ** off the Internet. The internal databases can be given the ** large, default limits. Databases managed by external sources can ** be given much smaller limits designed to prevent a denial of service ** attack. Developers might also want to use the [sqlite3_set_authorizer()] ** interface to further control untrusted SQL. The size of the database ** created by an untrusted script can be contained using the ** [max_page_count] [PRAGMA]. ** ** New run-time limit categories may be added in future releases. ** ** Requirements: ** [H12762] [H12766] [H12769] */ int sqlite3_limit(sqlite3*, int id, int newVal); /* ** CAPI3REF: Run-Time Limit Categories {H12790} ** KEYWORDS: {limit category} {limit categories} ** ** These constants define various performance limits ** that can be lowered at run-time using [sqlite3_limit()]. ** The synopsis of the meanings of the various limits is shown below. ** Additional information is available at [limits | Limits in SQLite]. ** **
**
SQLITE_LIMIT_LENGTH
**
The maximum size of any string or BLOB or table row.
** **
SQLITE_LIMIT_SQL_LENGTH
**
The maximum length of an SQL statement.
** **
SQLITE_LIMIT_COLUMN
**
The maximum number of columns in a table definition or in the ** result set of a [SELECT] or the maximum number of columns in an index ** or in an ORDER BY or GROUP BY clause.
** **
SQLITE_LIMIT_EXPR_DEPTH
**
The maximum depth of the parse tree on any expression.
** **
SQLITE_LIMIT_COMPOUND_SELECT
**
The maximum number of terms in a compound SELECT statement.
** **
SQLITE_LIMIT_VDBE_OP
**
The maximum number of instructions in a virtual machine program ** used to implement an SQL statement.
** **
SQLITE_LIMIT_FUNCTION_ARG
**
The maximum number of arguments on a function.
** **
SQLITE_LIMIT_ATTACHED
**
The maximum number of [ATTACH | attached databases].
** **
SQLITE_LIMIT_LIKE_PATTERN_LENGTH
**
The maximum length of the pattern argument to the [LIKE] or ** [GLOB] operators.
** **
SQLITE_LIMIT_VARIABLE_NUMBER
**
The maximum number of variables in an SQL statement that can ** be bound.
**
*/ #define SQLITE_LIMIT_LENGTH 0 #define SQLITE_LIMIT_SQL_LENGTH 1 #define SQLITE_LIMIT_COLUMN 2 #define SQLITE_LIMIT_EXPR_DEPTH 3 #define SQLITE_LIMIT_COMPOUND_SELECT 4 #define SQLITE_LIMIT_VDBE_OP 5 #define SQLITE_LIMIT_FUNCTION_ARG 6 #define SQLITE_LIMIT_ATTACHED 7 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH 8 #define SQLITE_LIMIT_VARIABLE_NUMBER 9 /* ** CAPI3REF: Compiling An SQL Statement {H13010} ** KEYWORDS: {SQL statement compiler} ** ** To execute an SQL query, it must first be compiled into a byte-code ** program using one of these routines. ** ** The first argument, "db", is a [database connection] obtained from a ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or ** [sqlite3_open16()]. The database connection must not have been closed. ** ** The second argument, "zSql", is the statement to be compiled, encoded ** as either UTF-8 or UTF-16. The sqlite3_prepare() and sqlite3_prepare_v2() ** interfaces use UTF-8, and sqlite3_prepare16() and sqlite3_prepare16_v2() ** use UTF-16. ** ** If the nByte argument is less than zero, then zSql is read up to the ** first zero terminator. If nByte is non-negative, then it is the maximum ** number of bytes read from zSql. When nByte is non-negative, the ** zSql string ends at either the first '\000' or '\u0000' character or ** the nByte-th byte, whichever comes first. If the caller knows ** that the supplied string is nul-terminated, then there is a small ** performance advantage to be gained by passing an nByte parameter that ** is equal to the number of bytes in the input string including ** the nul-terminator bytes. ** ** If pzTail is not NULL then *pzTail is made to point to the first byte ** past the end of the first SQL statement in zSql. These routines only ** compile the first statement in zSql, so *pzTail is left pointing to ** what remains uncompiled. ** ** *ppStmt is left pointing to a compiled [prepared statement] that can be ** executed using [sqlite3_step()]. If there is an error, *ppStmt is set ** to NULL. If the input text contains no SQL (if the input is an empty ** string or a comment) then *ppStmt is set to NULL. ** The calling procedure is responsible for deleting the compiled ** SQL statement using [sqlite3_finalize()] after it has finished with it. ** ppStmt may not be NULL. ** ** On success, [SQLITE_OK] is returned, otherwise an [error code] is returned. ** ** The sqlite3_prepare_v2() and sqlite3_prepare16_v2() interfaces are ** recommended for all new programs. The two older interfaces are retained ** for backwards compatibility, but their use is discouraged. ** In the "v2" interfaces, the prepared statement ** that is returned (the [sqlite3_stmt] object) contains a copy of the ** original SQL text. This causes the [sqlite3_step()] interface to ** behave a differently in two ways: ** **
    **
  1. ** If the database schema changes, instead of returning [SQLITE_SCHEMA] as it ** always used to do, [sqlite3_step()] will automatically recompile the SQL ** statement and try to run it again. If the schema has changed in ** a way that makes the statement no longer valid, [sqlite3_step()] will still ** return [SQLITE_SCHEMA]. But unlike the legacy behavior, [SQLITE_SCHEMA] is ** now a fatal error. Calling [sqlite3_prepare_v2()] again will not make the ** error go away. Note: use [sqlite3_errmsg()] to find the text ** of the parsing error that results in an [SQLITE_SCHEMA] return. **
    2. ** **
  2. ** When an error occurs, [sqlite3_step()] will return one of the detailed ** [error codes] or [extended error codes]. The legacy behavior was that ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code ** and you would have to make a second call to [sqlite3_reset()] in order ** to find the underlying cause of the problem. With the "v2" prepare ** interfaces, the underlying reason for the error is returned immediately. **
    3. **
** ** Requirements: ** [H13011] [H13012] [H13013] [H13014] [H13015] [H13016] [H13019] [H13021] ** */ int sqlite3_prepare( sqlite3 *db, /* Database handle */ const char *zSql, /* SQL statement, UTF-8 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const char **pzTail /* OUT: Pointer to unused portion of zSql */ ); int sqlite3_prepare_v2( sqlite3 *db, /* Database handle */ const char *zSql, /* SQL statement, UTF-8 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const char **pzTail /* OUT: Pointer to unused portion of zSql */ ); int sqlite3_prepare16( sqlite3 *db, /* Database handle */ const void *zSql, /* SQL statement, UTF-16 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const void **pzTail /* OUT: Pointer to unused portion of zSql */ ); int sqlite3_prepare16_v2( sqlite3 *db, /* Database handle */ const void *zSql, /* SQL statement, UTF-16 encoded */ int nByte, /* Maximum length of zSql in bytes. */ sqlite3_stmt **ppStmt, /* OUT: Statement handle */ const void **pzTail /* OUT: Pointer to unused portion of zSql */ ); /* ** CAPI3REF: Retrieving Statement SQL {H13100} ** ** This interface can be used to retrieve a saved copy of the original ** SQL text used to create a [prepared statement] if that statement was ** compiled using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()]. ** ** Requirements: ** [H13101] [H13102] [H13103] */ const char *sqlite3_sql(sqlite3_stmt *pStmt); /* ** CAPI3REF: Dynamically Typed Value Object {H15000} ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value} ** ** SQLite uses the sqlite3_value object to represent all values ** that can be stored in a database table. SQLite uses dynamic typing ** for the values it stores. Values stored in sqlite3_value objects ** can be integers, floating point values, strings, BLOBs, or NULL. ** ** An sqlite3_value object may be either "protected" or "unprotected". ** Some interfaces require a protected sqlite3_value. Other interfaces ** will accept either a protected or an unprotected sqlite3_value. ** Every interface that accepts sqlite3_value arguments specifies ** whether or not it requires a protected sqlite3_value. ** ** The terms "protected" and "unprotected" refer to whether or not ** a mutex is held. A internal mutex is held for a protected ** sqlite3_value object but no mutex is held for an unprotected ** sqlite3_value object. If SQLite is compiled to be single-threaded ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0) ** or if SQLite is run in one of reduced mutex modes ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD] ** then there is no distinction between protected and unprotected ** sqlite3_value objects and they can be used interchangeably. However, ** for maximum code portability it is recommended that applications ** still make the distinction between between protected and unprotected ** sqlite3_value objects even when not strictly required. ** ** The sqlite3_value objects that are passed as parameters into the ** implementation of [application-defined SQL functions] are protected. ** The sqlite3_value object returned by ** [sqlite3_column_value()] is unprotected. ** Unprotected sqlite3_value objects may only be used with ** [sqlite3_result_value()] and [sqlite3_bind_value()]. ** The [sqlite3_value_blob | sqlite3_value_type()] family of ** interfaces require protected sqlite3_value objects. */ typedef struct Mem sqlite3_value; /* ** CAPI3REF: SQL Function Context Object {H16001} ** ** The context in which an SQL function executes is stored in an ** sqlite3_context object. A pointer to an sqlite3_context object ** is always first parameter to [application-defined SQL functions]. ** The application-defined SQL function implementation will pass this ** pointer through into calls to [sqlite3_result_int | sqlite3_result()], ** [sqlite3_aggregate_context()], [sqlite3_user_data()], ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()], ** and/or [sqlite3_set_auxdata()]. */ typedef struct sqlite3_context sqlite3_context; /* ** CAPI3REF: Binding Values To Prepared Statements {H13500} ** KEYWORDS: {host parameter} {host parameters} {host parameter name} ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding} ** ** In the SQL strings input to [sqlite3_prepare_v2()] and its variants, ** literals may be replaced by a [parameter] in one of these forms: ** **
    **
  • ? **
  • ?NNN **
  • :VVV **
  • @VVV **
  • $VVV **
** ** In the parameter forms shown above NNN is an integer literal, ** and VVV is an alpha-numeric parameter name. The values of these ** parameters (also called "host parameter names" or "SQL parameters") ** can be set using the sqlite3_bind_*() routines defined here. ** ** The first argument to the sqlite3_bind_*() routines is always ** a pointer to the [sqlite3_stmt] object returned from ** [sqlite3_prepare_v2()] or its variants. ** ** The second argument is the index of the SQL parameter to be set. ** The leftmost SQL parameter has an index of 1. When the same named ** SQL parameter is used more than once, second and subsequent ** occurrences have the same index as the first occurrence. ** The index for named parameters can be looked up using the ** [sqlite3_bind_parameter_index()] API if desired. The index ** for "?NNN" parameters is the value of NNN. ** The NNN value must be between 1 and the [sqlite3_limit()] ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999). ** ** The third argument is the value to bind to the parameter. ** ** In those routines that have a fourth argument, its value is the ** number of bytes in the parameter. To be clear: the value is the ** number of bytes in the value, not the number of characters. ** If the fourth parameter is negative, the length of the string is ** the number of bytes up to the first zero terminator. ** ** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and ** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or ** string after SQLite has finished with it. If the fifth argument is ** the special value [SQLITE_STATIC], then SQLite assumes that the ** information is in static, unmanaged space and does not need to be freed. ** If the fifth argument has the value [SQLITE_TRANSIENT], then ** SQLite makes its own private copy of the data immediately, before ** the sqlite3_bind_*() routine returns. ** ** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that ** is filled with zeroes. A zeroblob uses a fixed amount of memory ** (just an integer to hold its size) while it is being processed. ** Zeroblobs are intended to serve as placeholders for BLOBs whose ** content is later written using ** [sqlite3_blob_open | incremental BLOB I/O] routines. ** A negative value for the zeroblob results in a zero-length BLOB. ** ** The sqlite3_bind_*() routines must be called after ** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and ** before [sqlite3_step()]. ** Bindings are not cleared by the [sqlite3_reset()] routine. ** Unbound parameters are interpreted as NULL. ** ** These routines return [SQLITE_OK] on success or an error code if ** anything goes wrong. [SQLITE_RANGE] is returned if the parameter ** index is out of range. [SQLITE_NOMEM] is returned if malloc() fails. ** [SQLITE_MISUSE] might be returned if these routines are called on a ** virtual machine that is the wrong state or which has already been finalized. ** Detection of misuse is unreliable. Applications should not depend ** on SQLITE_MISUSE returns. SQLITE_MISUSE is intended to indicate a ** a logic error in the application. Future versions of SQLite might ** panic rather than return SQLITE_MISUSE. ** ** See also: [sqlite3_bind_parameter_count()], ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()]. ** ** Requirements: ** [H13506] [H13509] [H13512] [H13515] [H13518] [H13521] [H13524] [H13527] ** [H13530] [H13533] [H13536] [H13539] [H13542] [H13545] [H13548] [H13551] ** */ int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*)); int sqlite3_bind_double(sqlite3_stmt*, int, double); int sqlite3_bind_int(sqlite3_stmt*, int, int); int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64); int sqlite3_bind_null(sqlite3_stmt*, int); int sqlite3_bind_text(sqlite3_stmt*, int, const char*, int n, void(*)(void*)); int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*)); int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*); int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n); /* ** CAPI3REF: Number Of SQL Parameters {H13600} ** ** This routine can be used to find the number of [SQL parameters] ** in a [prepared statement]. SQL parameters are tokens of the ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as ** placeholders for values that are [sqlite3_bind_blob | bound] ** to the parameters at a later time. ** ** This routine actually returns the index of the largest (rightmost) ** parameter. For all forms except ?NNN, this will correspond to the ** number of unique parameters. If parameters of the ?NNN are used, ** there may be gaps in the list. ** ** See also: [sqlite3_bind_blob|sqlite3_bind()], ** [sqlite3_bind_parameter_name()], and ** [sqlite3_bind_parameter_index()]. ** ** Requirements: ** [H13601] */ int sqlite3_bind_parameter_count(sqlite3_stmt*); /* ** CAPI3REF: Name Of A Host Parameter {H13620} ** ** This routine returns a pointer to the name of the n-th ** [SQL parameter] in a [prepared statement]. ** SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA" ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA" ** respectively. ** In other words, the initial ":" or "$" or "@" or "?" ** is included as part of the name. ** Parameters of the form "?" without a following integer have no name ** and are also referred to as "anonymous parameters". ** ** The first host parameter has an index of 1, not 0. ** ** If the value n is out of range or if the n-th parameter is ** nameless, then NULL is returned. The returned string is ** always in UTF-8 encoding even if the named parameter was ** originally specified as UTF-16 in [sqlite3_prepare16()] or ** [sqlite3_prepare16_v2()]. ** ** See also: [sqlite3_bind_blob|sqlite3_bind()], ** [sqlite3_bind_parameter_count()], and ** [sqlite3_bind_parameter_index()]. ** ** Requirements: ** [H13621] */ const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int); /* ** CAPI3REF: Index Of A Parameter With A Given Name {H13640} ** ** Return the index of an SQL parameter given its name. The ** index value returned is suitable for use as the second ** parameter to [sqlite3_bind_blob|sqlite3_bind()]. A zero ** is returned if no matching parameter is found. The parameter ** name must be given in UTF-8 even if the original statement ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()]. ** ** See also: [sqlite3_bind_blob|sqlite3_bind()], ** [sqlite3_bind_parameter_count()], and ** [sqlite3_bind_parameter_index()]. ** ** Requirements: ** [H13641] */ int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName); /* ** CAPI3REF: Reset All Bindings On A Prepared Statement {H13660} ** ** Contrary to the intuition of many, [sqlite3_reset()] does not reset ** the [sqlite3_bind_blob | bindings] on a [prepared statement]. ** Use this routine to reset all host parameters to NULL. ** ** Requirements: ** [H13661] */ int sqlite3_clear_bindings(sqlite3_stmt*); /* ** CAPI3REF: Number Of Columns In A Result Set {H13710} ** ** Return the number of columns in the result set returned by the ** [prepared statement]. This routine returns 0 if pStmt is an SQL ** statement that does not return data (for example an [UPDATE]). ** ** Requirements: ** [H13711] */ int sqlite3_column_count(sqlite3_stmt *pStmt); /* ** CAPI3REF: Column Names In A Result Set {H13720} ** ** These routines return the name assigned to a particular column ** in the result set of a [SELECT] statement. The sqlite3_column_name() ** interface returns a pointer to a zero-terminated UTF-8 string ** and sqlite3_column_name16() returns a pointer to a zero-terminated ** UTF-16 string. The first parameter is the [prepared statement] ** that implements the [SELECT] statement. The second parameter is the ** column number. The leftmost column is number 0. ** ** The returned string pointer is valid until either the [prepared statement] ** is destroyed by [sqlite3_finalize()] or until the next call to ** sqlite3_column_name() or sqlite3_column_name16() on the same column. ** ** If sqlite3_malloc() fails during the processing of either routine ** (for example during a conversion from UTF-8 to UTF-16) then a ** NULL pointer is returned. ** ** The name of a result column is the value of the "AS" clause for ** that column, if there is an AS clause. If there is no AS clause ** then the name of the column is unspecified and may change from ** one release of SQLite to the next. ** ** Requirements: ** [H13721] [H13723] [H13724] [H13725] [H13726] [H13727] */ const char *sqlite3_column_name(sqlite3_stmt*, int N); const void *sqlite3_column_name16(sqlite3_stmt*, int N); /* ** CAPI3REF: Source Of Data In A Query Result {H13740} ** ** These routines provide a means to determine what column of what ** table in which database a result of a [SELECT] statement comes from. ** The name of the database or table or column can be returned as ** either a UTF-8 or UTF-16 string. The _database_ routines return ** the database name, the _table_ routines return the table name, and ** the origin_ routines return the column name. ** The returned string is valid until the [prepared statement] is destroyed ** using [sqlite3_finalize()] or until the same information is requested ** again in a different encoding. ** ** The names returned are the original un-aliased names of the ** database, table, and column. ** ** The first argument to the following calls is a [prepared statement]. ** These functions return information about the Nth column returned by ** the statement, where N is the second function argument. ** ** If the Nth column returned by the statement is an expression or ** subquery and is not a column value, then all of these functions return ** NULL. These routine might also return NULL if a memory allocation error ** occurs. Otherwise, they return the name of the attached database, table ** and column that query result column was extracted from. ** ** As with all other SQLite APIs, those postfixed with "16" return ** UTF-16 encoded strings, the other functions return UTF-8. {END} ** ** These APIs are only available if the library was compiled with the ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. ** ** {A13751} ** If two or more threads call one or more of these routines against the same ** prepared statement and column at the same time then the results are ** undefined. ** ** Requirements: ** [H13741] [H13742] [H13743] [H13744] [H13745] [H13746] [H13748] ** ** If two or more threads call one or more ** [sqlite3_column_database_name | column metadata interfaces] ** for the same [prepared statement] and result column ** at the same time then the results are undefined. */ const char *sqlite3_column_database_name(sqlite3_stmt*,int); const void *sqlite3_column_database_name16(sqlite3_stmt*,int); const char *sqlite3_column_table_name(sqlite3_stmt*,int); const void *sqlite3_column_table_name16(sqlite3_stmt*,int); const char *sqlite3_column_origin_name(sqlite3_stmt*,int); const void *sqlite3_column_origin_name16(sqlite3_stmt*,int); /* ** CAPI3REF: Declared Datatype Of A Query Result {H13760} ** ** The first parameter is a [prepared statement]. ** If this statement is a [SELECT] statement and the Nth column of the ** returned result set of that [SELECT] is a table column (not an ** expression or subquery) then the declared type of the table ** column is returned. If the Nth column of the result set is an ** expression or subquery, then a NULL pointer is returned. ** The returned string is always UTF-8 encoded. {END} ** ** For example, given the database schema: ** ** CREATE TABLE t1(c1 VARIANT); ** ** and the following statement to be compiled: ** ** SELECT c1 + 1, c1 FROM t1; ** ** this routine would return the string "VARIANT" for the second result ** column (i==1), and a NULL pointer for the first result column (i==0). ** ** SQLite uses dynamic run-time typing. So just because a column ** is declared to contain a particular type does not mean that the ** data stored in that column is of the declared type. SQLite is ** strongly typed, but the typing is dynamic not static. Type ** is associated with individual values, not with the containers ** used to hold those values. ** ** Requirements: ** [H13761] [H13762] [H13763] */ const char *sqlite3_column_decltype(sqlite3_stmt*,int); const void *sqlite3_column_decltype16(sqlite3_stmt*,int); /* ** CAPI3REF: Evaluate An SQL Statement {H13200} ** ** After a [prepared statement] has been prepared using either ** [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] or one of the legacy ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function ** must be called one or more times to evaluate the statement. ** ** The details of the behavior of the sqlite3_step() interface depend ** on whether the statement was prepared using the newer "v2" interface ** [sqlite3_prepare_v2()] and [sqlite3_prepare16_v2()] or the older legacy ** interface [sqlite3_prepare()] and [sqlite3_prepare16()]. The use of the ** new "v2" interface is recommended for new applications but the legacy ** interface will continue to be supported. ** ** In the legacy interface, the return value will be either [SQLITE_BUSY], ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE]. ** With the "v2" interface, any of the other [result codes] or ** [extended result codes] might be returned as well. ** ** [SQLITE_BUSY] means that the database engine was unable to acquire the ** database locks it needs to do its job. If the statement is a [COMMIT] ** or occurs outside of an explicit transaction, then you can retry the ** statement. If the statement is not a [COMMIT] and occurs within a ** explicit transaction then you should rollback the transaction before ** continuing. ** ** [SQLITE_DONE] means that the statement has finished executing ** successfully. sqlite3_step() should not be called again on this virtual ** machine without first calling [sqlite3_reset()] to reset the virtual ** machine back to its initial state. ** ** If the SQL statement being executed returns any data, then [SQLITE_ROW] ** is returned each time a new row of data is ready for processing by the ** caller. The values may be accessed using the [column access functions]. ** sqlite3_step() is called again to retrieve the next row of data. ** ** [SQLITE_ERROR] means that a run-time error (such as a constraint ** violation) has occurred. sqlite3_step() should not be called again on ** the VM. More information may be found by calling [sqlite3_errmsg()]. ** With the legacy interface, a more specific error code (for example, ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth) ** can be obtained by calling [sqlite3_reset()] on the ** [prepared statement]. In the "v2" interface, ** the more specific error code is returned directly by sqlite3_step(). ** ** [SQLITE_MISUSE] means that the this routine was called inappropriately. ** Perhaps it was called on a [prepared statement] that has ** already been [sqlite3_finalize | finalized] or on one that had ** previously returned [SQLITE_ERROR] or [SQLITE_DONE]. Or it could ** be the case that the same database connection is being used by two or ** more threads at the same moment in time. ** ** Goofy Interface Alert: In the legacy interface, the sqlite3_step() ** API always returns a generic error code, [SQLITE_ERROR], following any ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE]. You must call ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the ** specific [error codes] that better describes the error. ** We admit that this is a goofy design. The problem has been fixed ** with the "v2" interface. If you prepare all of your SQL statements ** using either [sqlite3_prepare_v2()] or [sqlite3_prepare16_v2()] instead ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces, ** then the more specific [error codes] are returned directly ** by sqlite3_step(). The use of the "v2" interface is recommended. ** ** Requirements: ** [H13202] [H15304] [H15306] [H15308] [H15310] */ int sqlite3_step(sqlite3_stmt*); /* ** CAPI3REF: Number of columns in a result set {H13770} ** ** Returns the number of values in the current row of the result set. ** ** Requirements: ** [H13771] [H13772] */ int sqlite3_data_count(sqlite3_stmt *pStmt); /* ** CAPI3REF: Fundamental Datatypes {H10265} ** KEYWORDS: SQLITE_TEXT ** ** {H10266} Every value in SQLite has one of five fundamental datatypes: ** **
    **
  • 64-bit signed integer **
  • 64-bit IEEE floating point number **
  • string **
  • BLOB **
  • NULL **
{END} ** ** These constants are codes for each of those types. ** ** Note that the SQLITE_TEXT constant was also used in SQLite version 2 ** for a completely different meaning. Software that links against both ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not ** SQLITE_TEXT. */ #define SQLITE_INTEGER 1 #define SQLITE_FLOAT 2 #define SQLITE_BLOB 4 #define SQLITE_NULL 5 #ifdef SQLITE_TEXT # undef SQLITE_TEXT #else # define SQLITE_TEXT 3 #endif #define SQLITE3_TEXT 3 /* ** CAPI3REF: Result Values From A Query {H13800} ** KEYWORDS: {column access functions} ** ** These routines form the "result set query" interface. ** ** These routines return information about a single column of the current ** result row of a query. In every case the first argument is a pointer ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*] ** that was returned from [sqlite3_prepare_v2()] or one of its variants) ** and the second argument is the index of the column for which information ** should be returned. The leftmost column of the result set has the index 0. ** ** If the SQL statement does not currently point to a valid row, or if the ** column index is out of range, the result is undefined. ** These routines may only be called when the most recent call to ** [sqlite3_step()] has returned [SQLITE_ROW] and neither ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently. ** If any of these routines are called after [sqlite3_reset()] or ** [sqlite3_finalize()] or after [sqlite3_step()] has returned ** something other than [SQLITE_ROW], the results are undefined. ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()] ** are called from a different thread while any of these routines ** are pending, then the results are undefined. ** ** The sqlite3_column_type() routine returns the ** [SQLITE_INTEGER | datatype code] for the initial data type ** of the result column. The returned value is one of [SQLITE_INTEGER], ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL]. The value ** returned by sqlite3_column_type() is only meaningful if no type ** conversions have occurred as described below. After a type conversion, ** the value returned by sqlite3_column_type() is undefined. Future ** versions of SQLite may change the behavior of sqlite3_column_type() ** following a type conversion. ** ** If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes() ** routine returns the number of bytes in that BLOB or string. ** If the result is a UTF-16 string, then sqlite3_column_bytes() converts ** the string to UTF-8 and then returns the number of bytes. ** If the result is a numeric value then sqlite3_column_bytes() uses ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns ** the number of bytes in that string. ** The value returned does not include the zero terminator at the end ** of the string. For clarity: the value returned is the number of ** bytes in the string, not the number of characters. ** ** Strings returned by sqlite3_column_text() and sqlite3_column_text16(), ** even empty strings, are always zero terminated. The return ** value from sqlite3_column_blob() for a zero-length BLOB is an arbitrary ** pointer, possibly even a NULL pointer. ** ** The sqlite3_column_bytes16() routine is similar to sqlite3_column_bytes() ** but leaves the result in UTF-16 in native byte order instead of UTF-8. ** The zero terminator is not included in this count. ** ** The object returned by [sqlite3_column_value()] is an ** [unprotected sqlite3_value] object. An unprotected sqlite3_value object ** may only be used with [sqlite3_bind_value()] and [sqlite3_result_value()]. ** If the [unprotected sqlite3_value] object returned by ** [sqlite3_column_value()] is used in any other way, including calls ** to routines like [sqlite3_value_int()], [sqlite3_value_text()], ** or [sqlite3_value_bytes()], then the behavior is undefined. ** ** These routines attempt to convert the value where appropriate. For ** example, if the internal representation is FLOAT and a text result ** is requested, [sqlite3_snprintf()] is used internally to perform the ** conversion automatically. The following table details the conversions ** that are applied: ** **
** **
Internal
Type 		Requested
Type 		Conversion ** **
NULL INTEGER Result is 0 **
NULL FLOAT Result is 0.0 **
NULL TEXT Result is NULL pointer **
NULL BLOB Result is NULL pointer **
INTEGER FLOAT Convert from integer to float **
INTEGER TEXT ASCII rendering of the integer **
INTEGER BLOB Same as INTEGER->TEXT **
FLOAT INTEGER Convert from float to integer **
FLOAT TEXT ASCII rendering of the float **
FLOAT BLOB Same as FLOAT->TEXT **
TEXT INTEGER Use atoi() **
TEXT FLOAT Use atof() **
TEXT BLOB No change **
BLOB INTEGER Convert to TEXT then use atoi() **
BLOB FLOAT Convert to TEXT then use atof() **
BLOB TEXT Add a zero terminator if needed **
**
** ** The table above makes reference to standard C library functions atoi() ** and atof(). SQLite does not really use these functions. It has its ** own equivalent internal routines. The atoi() and atof() names are ** used in the table for brevity and because they are familiar to most ** C programmers. ** ** Note that when type conversions occur, pointers returned by prior ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or ** sqlite3_column_text16() may be invalidated. ** Type conversions and pointer invalidations might occur ** in the following cases: ** **
    **
  • The initial content is a BLOB and sqlite3_column_text() or ** sqlite3_column_text16() is called. A zero-terminator might ** need to be added to the string.
    • **
  • The initial content is UTF-8 text and sqlite3_column_bytes16() or ** sqlite3_column_text16() is called. The content must be converted ** to UTF-16.
    • **
  • The initial content is UTF-16 text and sqlite3_column_bytes() or ** sqlite3_column_text() is called. The content must be converted ** to UTF-8.
    • **
** ** Conversions between UTF-16be and UTF-16le are always done in place and do ** not invalidate a prior pointer, though of course the content of the buffer ** that the prior pointer points to will have been modified. Other kinds ** of conversion are done in place when it is possible, but sometimes they ** are not possible and in those cases prior pointers are invalidated. ** ** The safest and easiest to remember policy is to invoke these routines ** in one of the following ways: ** **
    **
  • sqlite3_column_text() followed by sqlite3_column_bytes()
    • **
  • sqlite3_column_blob() followed by sqlite3_column_bytes()
    • **
  • sqlite3_column_text16() followed by sqlite3_column_bytes16()
    • **
** ** In other words, you should call sqlite3_column_text(), ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result ** into the desired format, then invoke sqlite3_column_bytes() or ** sqlite3_column_bytes16() to find the size of the result. Do not mix calls ** to sqlite3_column_text() or sqlite3_column_blob() with calls to ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16() ** with calls to sqlite3_column_bytes(). ** ** The pointers returned are valid until a type conversion occurs as ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or ** [sqlite3_finalize()] is called. The memory space used to hold strings ** and BLOBs is freed automatically. Do not pass the pointers returned ** [sqlite3_column_blob()], [sqlite3_column_text()], etc. into ** [sqlite3_free()]. ** ** If a memory allocation error occurs during the evaluation of any ** of these routines, a default value is returned. The default value ** is either the integer 0, the floating point number 0.0, or a NULL ** pointer. Subsequent calls to [sqlite3_errcode()] will return ** [SQLITE_NOMEM]. ** ** Requirements: ** [H13803] [H13806] [H13809] [H13812] [H13815] [H13818] [H13821] [H13824] ** [H13827] [H13830] */ const void *sqlite3_column_blob(sqlite3_stmt*, int iCol); int sqlite3_column_bytes(sqlite3_stmt*, int iCol); int sqlite3_column_bytes16(sqlite3_stmt*, int iCol); double sqlite3_column_double(sqlite3_stmt*, int iCol); int sqlite3_column_int(sqlite3_stmt*, int iCol); sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol); const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol); const void *sqlite3_column_text16(sqlite3_stmt*, int iCol); int sqlite3_column_type(sqlite3_stmt*, int iCol); sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol); /* ** CAPI3REF: Destroy A Prepared Statement Object {H13300} ** ** The sqlite3_finalize() function is called to delete a [prepared statement]. ** If the statement was executed successfully or not executed at all, then ** SQLITE_OK is returned. If execution of the statement failed then an ** [error code] or [extended error code] is returned. ** ** This routine can be called at any point during the execution of the ** [prepared statement]. If the virtual machine has not ** completed execution when this routine is called, that is like ** encountering an error or an [sqlite3_interrupt | interrupt]. ** Incomplete updates may be rolled back and transactions canceled, ** depending on the circumstances, and the ** [error code] returned will be [SQLITE_ABORT]. ** ** Requirements: ** [H11302] [H11304] */ int sqlite3_finalize(sqlite3_stmt *pStmt); /* ** CAPI3REF: Reset A Prepared Statement Object {H13330} ** ** The sqlite3_reset() function is called to reset a [prepared statement] ** object back to its initial state, ready to be re-executed. ** Any SQL statement variables that had values bound to them using ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values. ** Use [sqlite3_clear_bindings()] to reset the bindings. ** ** {H11332} The [sqlite3_reset(S)] interface resets the [prepared statement] S ** back to the beginning of its program. ** ** {H11334} If the most recent call to [sqlite3_step(S)] for the ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE], ** or if [sqlite3_step(S)] has never before been called on S, ** then [sqlite3_reset(S)] returns [SQLITE_OK]. ** ** {H11336} If the most recent call to [sqlite3_step(S)] for the ** [prepared statement] S indicated an error, then ** [sqlite3_reset(S)] returns an appropriate [error code]. ** ** {H11338} The [sqlite3_reset(S)] interface does not change the values ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S. */ int sqlite3_reset(sqlite3_stmt *pStmt); /* ** CAPI3REF: Create Or Redefine SQL Functions {H16100} ** KEYWORDS: {function creation routines} ** KEYWORDS: {application-defined SQL function} ** KEYWORDS: {application-defined SQL functions} ** ** These two functions (collectively known as "function creation routines") ** are used to add SQL functions or aggregates or to redefine the behavior ** of existing SQL functions or aggregates. The only difference between the ** two is that the second parameter, the name of the (scalar) function or ** aggregate, is encoded in UTF-8 for sqlite3_create_function() and UTF-16 ** for sqlite3_create_function16(). ** ** The first parameter is the [database connection] to which the SQL ** function is to be added. If a single program uses more than one database ** connection internally, then SQL functions must be added individually to ** each database connection. ** ** The second parameter is the name of the SQL function to be created or ** redefined. The length of the name is limited to 255 bytes, exclusive of ** the zero-terminator. Note that the name length limit is in bytes, not ** characters. Any attempt to create a function with a longer name ** will result in [SQLITE_ERROR] being returned. ** ** The third parameter (nArg) ** is the number of arguments that the SQL function or ** aggregate takes. If this parameter is negative, then the SQL function or ** aggregate may take any number of arguments. ** ** The fourth parameter, eTextRep, specifies what ** [SQLITE_UTF8 | text encoding] this SQL function prefers for ** its parameters. Any SQL function implementation should be able to work ** work with UTF-8, UTF-16le, or UTF-16be. But some implementations may be ** more efficient with one encoding than another. It is allowed to ** invoke sqlite3_create_function() or sqlite3_create_function16() multiple ** times with the same function but with different values of eTextRep. ** When multiple implementations of the same function are available, SQLite ** will pick the one that involves the least amount of data conversion. ** If there is only a single implementation which does not care what text ** encoding is used, then the fourth argument should be [SQLITE_ANY]. ** ** The fifth parameter is an arbitrary pointer. The implementation of the ** function can gain access to this pointer using [sqlite3_user_data()]. ** ** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are ** pointers to C-language functions that implement the SQL function or ** aggregate. A scalar SQL function requires an implementation of the xFunc ** callback only, NULL pointers should be passed as the xStep and xFinal ** parameters. An aggregate SQL function requires an implementation of xStep ** and xFinal and NULL should be passed for xFunc. To delete an existing ** SQL function or aggregate, pass NULL for all three function callbacks. ** ** It is permitted to register multiple implementations of the same ** functions with the same name but with either differing numbers of ** arguments or differing preferred text encodings. SQLite will use ** the implementation most closely matches the way in which the ** SQL function is used. A function implementation with a non-negative ** nArg parameter is a better match than a function implementation with ** a negative nArg. A function where the preferred text encoding ** matches the database encoding is a better ** match than a function where the encoding is different. ** A function where the encoding difference is between UTF16le and UTF16be ** is a closer match than a function where the encoding difference is ** between UTF8 and UTF16. ** ** Built-in functions may be overloaded by new application-defined functions. ** The first application-defined function with a given name overrides all ** built-in functions in the same [database connection] with the same name. ** Subsequent application-defined functions of the same name only override ** prior application-defined functions that are an exact match for the ** number of parameters and preferred encoding. ** ** An application-defined function is permitted to call other ** SQLite interfaces. However, such calls must not ** close the database connection nor finalize or reset the prepared ** statement in which the function is running. ** ** Requirements: ** [H16103] [H16106] [H16109] [H16112] [H16118] [H16121] [H16124] [H16127] ** [H16130] [H16133] [H16136] [H16139] [H16142] */ int sqlite3_create_function( sqlite3 *db, const char *zFunctionName, int nArg, int eTextRep, void *pApp, void (*xFunc)(sqlite3_context*,int,sqlite3_value**), void (*xStep)(sqlite3_context*,int,sqlite3_value**), void (*xFinal)(sqlite3_context*) ); int sqlite3_create_function16( sqlite3 *db, const void *zFunctionName, int nArg, int eTextRep, void *pApp, void (*xFunc)(sqlite3_context*,int,sqlite3_value**), void (*xStep)(sqlite3_context*,int,sqlite3_value**), void (*xFinal)(sqlite3_context*) ); /* ** CAPI3REF: Text Encodings {H10267} ** ** These constant define integer codes that represent the various ** text encodings supported by SQLite. */ #define SQLITE_UTF8 1 #define SQLITE_UTF16LE 2 #define SQLITE_UTF16BE 3 #define SQLITE_UTF16 4 /* Use native byte order */ #define SQLITE_ANY 5 /* sqlite3_create_function only */ #define SQLITE_UTF16_ALIGNED 8 /* sqlite3_create_collation only */ /* ** CAPI3REF: Deprecated Functions ** DEPRECATED ** ** These functions are [deprecated]. In order to maintain ** backwards compatibility with older code, these functions continue ** to be supported. However, new applications should avoid ** the use of these functions. To help encourage people to avoid ** using these functions, we are not going to tell you what they do. */ #ifndef SQLITE_OMIT_DEPRECATED SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*); SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*); SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*); SQLITE_DEPRECATED int sqlite3_global_recover(void); SQLITE_DEPRECATED void sqlite3_thread_cleanup(void); SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),void*,sqlite3_int64); #endif /* ** CAPI3REF: Obtaining SQL Function Parameter Values {H15100} ** ** The C-language implementation of SQL functions and aggregates uses ** this set of interface routines to access the parameter values on ** the function or aggregate. ** ** The xFunc (for scalar functions) or xStep (for aggregates) parameters ** to [sqlite3_create_function()] and [sqlite3_create_function16()] ** define callbacks that implement the SQL functions and aggregates. ** The 4th parameter to these callbacks is an array of pointers to ** [protected sqlite3_value] objects. There is one [sqlite3_value] object for ** each parameter to the SQL function. These routines are used to ** extract values from the [sqlite3_value] objects. ** ** These routines work only with [protected sqlite3_value] objects. ** Any attempt to use these routines on an [unprotected sqlite3_value] ** object results in undefined behavior. ** ** These routines work just like the corresponding [column access functions] ** except that these routines take a single [protected sqlite3_value] object ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number. ** ** The sqlite3_value_text16() interface extracts a UTF-16 string ** in the native byte-order of the host machine. The ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces ** extract UTF-16 strings as big-endian and little-endian respectively. ** ** The sqlite3_value_numeric_type() interface attempts to apply ** numeric affinity to the value. This means that an attempt is ** made to convert the value to an integer or floating point. If ** such a conversion is possible without loss of information (in other ** words, if the value is a string that looks like a number) ** then the conversion is performed. Otherwise no conversion occurs. ** The [SQLITE_INTEGER | datatype] after conversion is returned. ** ** Please pay particular attention to the fact that the pointer returned ** from [sqlite3_value_blob()], [sqlite3_value_text()], or ** [sqlite3_value_text16()] can be invalidated by a subsequent call to ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()], ** or [sqlite3_value_text16()]. ** ** These routines must be called from the same thread as ** the SQL function that supplied the [sqlite3_value*] parameters. ** ** Requirements: ** [H15103] [H15106] [H15109] [H15112] [H15115] [H15118] [H15121] [H15124] ** [H15127] [H15130] [H15133] [H15136] */ const void *sqlite3_value_blob(sqlite3_value*); int sqlite3_value_bytes(sqlite3_value*); int sqlite3_value_bytes16(sqlite3_value*); double sqlite3_value_double(sqlite3_value*); int sqlite3_value_int(sqlite3_value*); sqlite3_int64 sqlite3_value_int64(sqlite3_value*); const unsigned char *sqlite3_value_text(sqlite3_value*); const void *sqlite3_value_text16(sqlite3_value*); const void *sqlite3_value_text16le(sqlite3_value*); const void *sqlite3_value_text16be(sqlite3_value*); int sqlite3_value_type(sqlite3_value*); int sqlite3_value_numeric_type(sqlite3_value*); /* ** CAPI3REF: Obtain Aggregate Function Context {H16210} ** ** The implementation of aggregate SQL functions use this routine to allocate ** a structure for storing their state. ** ** The first time the sqlite3_aggregate_context() routine is called for a ** particular aggregate, SQLite allocates nBytes of memory, zeroes out that ** memory, and returns a pointer to it. On second and subsequent calls to ** sqlite3_aggregate_context() for the same aggregate function index, ** the same buffer is returned. The implementation of the aggregate can use ** the returned buffer to accumulate data. ** ** SQLite automatically frees the allocated buffer when the aggregate ** query concludes. ** ** The first parameter should be a copy of the ** [sqlite3_context | SQL function context] that is the first parameter ** to the callback routine that implements the aggregate function. ** ** This routine must be called from the same thread in which ** the aggregate SQL function is running. ** ** Requirements: ** [H16211] [H16213] [H16215] [H16217] */ void *sqlite3_aggregate_context(sqlite3_context*, int nBytes); /* ** CAPI3REF: User Data For Functions {H16240} ** ** The sqlite3_user_data() interface returns a copy of ** the pointer that was the pUserData parameter (the 5th parameter) ** of the [sqlite3_create_function()] ** and [sqlite3_create_function16()] routines that originally ** registered the application defined function. {END} ** ** This routine must be called from the same thread in which ** the application-defined function is running. ** ** Requirements: ** [H16243] */ void *sqlite3_user_data(sqlite3_context*); /* ** CAPI3REF: Database Connection For Functions {H16250} ** ** The sqlite3_context_db_handle() interface returns a copy of ** the pointer to the [database connection] (the 1st parameter) ** of the [sqlite3_create_function()] ** and [sqlite3_create_function16()] routines that originally ** registered the application defined function. ** ** Requirements: ** [H16253] */ sqlite3 *sqlite3_context_db_handle(sqlite3_context*); /* ** CAPI3REF: Function Auxiliary Data {H16270} ** ** The following two functions may be used by scalar SQL functions to ** associate metadata with argument values. If the same value is passed to ** multiple invocations of the same SQL function during query execution, under ** some circumstances the associated metadata may be preserved. This may ** be used, for example, to add a regular-expression matching scalar ** function. The compiled version of the regular expression is stored as ** metadata associated with the SQL value passed as the regular expression ** pattern. The compiled regular expression can be reused on multiple ** invocations of the same function so that the original pattern string ** does not need to be recompiled on each invocation. ** ** The sqlite3_get_auxdata() interface returns a pointer to the metadata ** associated by the sqlite3_set_auxdata() function with the Nth argument ** value to the application-defined function. If no metadata has been ever ** been set for the Nth argument of the function, or if the corresponding ** function parameter has changed since the meta-data was set, ** then sqlite3_get_auxdata() returns a NULL pointer. ** ** The sqlite3_set_auxdata() interface saves the metadata ** pointed to by its 3rd parameter as the metadata for the N-th ** argument of the application-defined function. Subsequent ** calls to sqlite3_get_auxdata() might return this data, if it has ** not been destroyed. ** If it is not NULL, SQLite will invoke the destructor ** function given by the 4th parameter to sqlite3_set_auxdata() on ** the metadata when the corresponding function parameter changes ** or when the SQL statement completes, whichever comes first. ** ** SQLite is free to call the destructor and drop metadata on any ** parameter of any function at any time. The only guarantee is that ** the destructor will be called before the metadata is dropped. ** ** In practice, metadata is preserved between function calls for ** expressions that are constant at compile time. This includes literal ** values and SQL variables. ** ** These routines must be called from the same thread in which ** the SQL function is running. ** ** Requirements: ** [H16272] [H16274] [H16276] [H16277] [H16278] [H16279] */ void *sqlite3_get_auxdata(sqlite3_context*, int N); void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*)); /* ** CAPI3REF: Constants Defining Special Destructor Behavior {H10280} ** ** These are special values for the destructor that is passed in as the ** final argument to routines like [sqlite3_result_blob()]. If the destructor ** argument is SQLITE_STATIC, it means that the content pointer is constant ** and will never change. It does not need to be destroyed. The ** SQLITE_TRANSIENT value means that the content will likely change in ** the near future and that SQLite should make its own private copy of ** the content before returning. ** ** The typedef is necessary to work around problems in certain ** C++ compilers. See ticket #2191. */ typedef void (*sqlite3_destructor_type)(void*); #define SQLITE_STATIC ((sqlite3_destructor_type)0) #define SQLITE_TRANSIENT ((sqlite3_destructor_type)-1) /* ** CAPI3REF: Setting The Result Of An SQL Function {H16400} ** ** These routines are used by the xFunc or xFinal callbacks that ** implement SQL functions and aggregates. See ** [sqlite3_create_function()] and [sqlite3_create_function16()] ** for additional information. ** ** These functions work very much like the [parameter binding] family of ** functions used to bind values to host parameters in prepared statements. ** Refer to the [SQL parameter] documentation for additional information. ** ** The sqlite3_result_blob() interface sets the result from ** an application-defined function to be the BLOB whose content is pointed ** to by the second parameter and which is N bytes long where N is the ** third parameter. ** ** The sqlite3_result_zeroblob() interfaces set the result of ** the application-defined function to be a BLOB containing all zero ** bytes and N bytes in size, where N is the value of the 2nd parameter. ** ** The sqlite3_result_double() interface sets the result from ** an application-defined function to be a floating point value specified ** by its 2nd argument. ** ** The sqlite3_result_error() and sqlite3_result_error16() functions ** cause the implemented SQL function to throw an exception. ** SQLite uses the string pointed to by the ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16() ** as the text of an error message. SQLite interprets the error ** message string from sqlite3_result_error() as UTF-8. SQLite ** interprets the string from sqlite3_result_error16() as UTF-16 in native ** byte order. If the third parameter to sqlite3_result_error() ** or sqlite3_result_error16() is negative then SQLite takes as the error ** message all text up through the first zero character. ** If the third parameter to sqlite3_result_error() or ** sqlite3_result_error16() is non-negative then SQLite takes that many ** bytes (not characters) from the 2nd parameter as the error message. ** The sqlite3_result_error() and sqlite3_result_error16() ** routines make a private copy of the error message text before ** they return. Hence, the calling function can deallocate or ** modify the text after they return without harm. ** The sqlite3_result_error_code() function changes the error code ** returned by SQLite as a result of an error in a function. By default, ** the error code is SQLITE_ERROR. A subsequent call to sqlite3_result_error() ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR. ** ** The sqlite3_result_toobig() interface causes SQLite to throw an error ** indicating that a string or BLOB is to long to represent. ** ** The sqlite3_result_nomem() interface causes SQLite to throw an error ** indicating that a memory allocation failed. ** ** The sqlite3_result_int() interface sets the return value ** of the application-defined function to be the 32-bit signed integer ** value given in the 2nd argument. ** The sqlite3_result_int64() interface sets the return value ** of the application-defined function to be the 64-bit signed integer ** value given in the 2nd argument. ** ** The sqlite3_result_null() interface sets the return value ** of the application-defined function to be NULL. ** ** The sqlite3_result_text(), sqlite3_result_text16(), ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces ** set the return value of the application-defined function to be ** a text string which is represented as UTF-8, UTF-16 native byte order, ** UTF-16 little endian, or UTF-16 big endian, respectively. ** SQLite takes the text result from the application from ** the 2nd parameter of the sqlite3_result_text* interfaces. ** If the 3rd parameter to the sqlite3_result_text* interfaces ** is negative, then SQLite takes result text from the 2nd parameter ** through the first zero character. ** If the 3rd parameter to the sqlite3_result_text* interfaces ** is non-negative, then as many bytes (not characters) of the text ** pointed to by the 2nd parameter are taken as the application-defined ** function result. ** If the 4th parameter to the sqlite3_result_text* interfaces ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that ** function as the destructor on the text or BLOB result when it has ** finished using that result. ** If the 4th parameter to the sqlite3_result_text* interfaces or ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite ** assumes that the text or BLOB result is in constant space and does not ** copy the it or call a destructor when it has finished using that result. ** If the 4th parameter to the sqlite3_result_text* interfaces ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT ** then SQLite makes a copy of the result into space obtained from ** from [sqlite3_malloc()] before it returns. ** ** The sqlite3_result_value() interface sets the result of ** the application-defined function to be a copy the ** [unprotected sqlite3_value] object specified by the 2nd parameter. The ** sqlite3_result_value() interface makes a copy of the [sqlite3_value] ** so that the [sqlite3_value] specified in the parameter may change or ** be deallocated after sqlite3_result_value() returns without harm. ** A [protected sqlite3_value] object may always be used where an ** [unprotected sqlite3_value] object is required, so either ** kind of [sqlite3_value] object can be used with this interface. ** ** If these routines are called from within the different thread ** than the one containing the application-defined function that received ** the [sqlite3_context] pointer, the results are undefined. ** ** Requirements: ** [H16403] [H16406] [H16409] [H16412] [H16415] [H16418] [H16421] [H16424] ** [H16427] [H16430] [H16433] [H16436] [H16439] [H16442] [H16445] [H16448] ** [H16451] [H16454] [H16457] [H16460] [H16463] */ void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*)); void sqlite3_result_double(sqlite3_context*, double); void sqlite3_result_error(sqlite3_context*, const char*, int); void sqlite3_result_error16(sqlite3_context*, const void*, int); void sqlite3_result_error_toobig(sqlite3_context*); void sqlite3_result_error_nomem(sqlite3_context*); void sqlite3_result_error_code(sqlite3_context*, int); void sqlite3_result_int(sqlite3_context*, int); void sqlite3_result_int64(sqlite3_context*, sqlite3_int64); void sqlite3_result_null(sqlite3_context*); void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*)); void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*)); void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*)); void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*)); void sqlite3_result_value(sqlite3_context*, sqlite3_value*); void sqlite3_result_zeroblob(sqlite3_context*, int n); /* ** CAPI3REF: Define New Collating Sequences {H16600} ** ** These functions are used to add new collation sequences to the ** [database connection] specified as the first argument. ** ** The name of the new collation sequence is specified as a UTF-8 string ** for sqlite3_create_collation() and sqlite3_create_collation_v2() ** and a UTF-16 string for sqlite3_create_collation16(). In all cases ** the name is passed as the second function argument. ** ** The third argument may be one of the constants [SQLITE_UTF8], ** [SQLITE_UTF16LE] or [SQLITE_UTF16BE], indicating that the user-supplied ** routine expects to be passed pointers to strings encoded using UTF-8, ** UTF-16 little-endian, or UTF-16 big-endian, respectively. The ** third argument might also be [SQLITE_UTF16_ALIGNED] to indicate that ** the routine expects pointers to 16-bit word aligned strings ** of UTF-16 in the native byte order of the host computer. ** ** A pointer to the user supplied routine must be passed as the fifth ** argument. If it is NULL, this is the same as deleting the collation ** sequence (so that SQLite cannot call it anymore). ** Each time the application supplied function is invoked, it is passed ** as its first parameter a copy of the void* passed as the fourth argument ** to sqlite3_create_collation() or sqlite3_create_collation16(). ** ** The remaining arguments to the application-supplied routine are two strings, ** each represented by a (length, data) pair and encoded in the encoding ** that was passed as the third argument when the collation sequence was ** registered. {END} The application defined collation routine should ** return negative, zero or positive if the first string is less than, ** equal to, or greater than the second string. i.e. (STRING1 - STRING2). ** ** The sqlite3_create_collation_v2() works like sqlite3_create_collation() ** except that it takes an extra argument which is a destructor for ** the collation. The destructor is called when the collation is ** destroyed and is passed a copy of the fourth parameter void* pointer ** of the sqlite3_create_collation_v2(). ** Collations are destroyed when they are overridden by later calls to the ** collation creation functions or when the [database connection] is closed ** using [sqlite3_close()]. ** ** Requirements: ** [H16603] [H16604] [H16606] [H16609] [H16612] [H16615] [H16618] [H16621] ** [H16624] [H16627] [H16630] */ int sqlite3_create_collation( sqlite3*, const char *zName, int eTextRep, void*, int(*xCompare)(void*,int,const void*,int,const void*) ); int sqlite3_create_collation_v2( sqlite3*, const char *zName, int eTextRep, void*, int(*xCompare)(void*,int,const void*,int,const void*), void(*xDestroy)(void*) ); int sqlite3_create_collation16( sqlite3*, const void *zName, int eTextRep, void*, int(*xCompare)(void*,int,const void*,int,const void*) ); /* ** CAPI3REF: Collation Needed Callbacks {H16700} ** ** To avoid having to register all collation sequences before a database ** can be used, a single callback function may be registered with the ** [database connection] to be called whenever an undefined collation ** sequence is required. ** ** If the function is registered using the sqlite3_collation_needed() API, ** then it is passed the names of undefined collation sequences as strings ** encoded in UTF-8. {H16703} If sqlite3_collation_needed16() is used, ** the names are passed as UTF-16 in machine native byte order. ** A call to either function replaces any existing callback. ** ** When the callback is invoked, the first argument passed is a copy ** of the second argument to sqlite3_collation_needed() or ** sqlite3_collation_needed16(). The second argument is the database ** connection. The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE], ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation ** sequence function required. The fourth parameter is the name of the ** required collation sequence. ** ** The callback function should register the desired collation using ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or ** [sqlite3_create_collation_v2()]. ** ** Requirements: ** [H16702] [H16704] [H16706] */ int sqlite3_collation_needed( sqlite3*, void*, void(*)(void*,sqlite3*,int eTextRep,const char*) ); int sqlite3_collation_needed16( sqlite3*, void*, void(*)(void*,sqlite3*,int eTextRep,const void*) ); /* ** Specify the key for an encrypted database. This routine should be ** called right after sqlite3_open(). ** ** The code to implement this API is not available in the public release ** of SQLite. */ int sqlite3_key( sqlite3 *db, /* Database to be rekeyed */ const void *pKey, int nKey /* The key */ ); /* ** Change the key on an open database. If the current database is not ** encrypted, this routine will encrypt it. If pNew==0 or nNew==0, the ** database is decrypted. ** ** The code to implement this API is not available in the public release ** of SQLite. */ int sqlite3_rekey( sqlite3 *db, /* Database to be rekeyed */ const void *pKey, int nKey /* The new key */ ); /* ** CAPI3REF: Suspend Execution For A Short Time {H10530} ** ** The sqlite3_sleep() function causes the current thread to suspend execution ** for at least a number of milliseconds specified in its parameter. ** ** If the operating system does not support sleep requests with ** millisecond time resolution, then the time will be rounded up to ** the nearest second. The number of milliseconds of sleep actually ** requested from the operating system is returned. ** ** SQLite implements this interface by calling the xSleep() ** method of the default [sqlite3_vfs] object. ** ** Requirements: [H10533] [H10536] */ int sqlite3_sleep(int); /* ** CAPI3REF: Name Of The Folder Holding Temporary Files {H10310} ** ** If this global variable is made to point to a string which is ** the name of a folder (a.k.a. directory), then all temporary files ** created by SQLite will be placed in that directory. If this variable ** is a NULL pointer, then SQLite performs a search for an appropriate ** temporary file directory. ** ** It is not safe to read or modify this variable in more than one ** thread at a time. It is not safe to read or modify this variable ** if a [database connection] is being used at the same time in a separate ** thread. ** It is intended that this variable be set once ** as part of process initialization and before any SQLite interface ** routines have been called and that this variable remain unchanged ** thereafter. ** ** The [temp_store_directory pragma] may modify this variable and cause ** it to point to memory obtained from [sqlite3_malloc]. Furthermore, ** the [temp_store_directory pragma] always assumes that any string ** that this variable points to is held in memory obtained from ** [sqlite3_malloc] and the pragma may attempt to free that memory ** using [sqlite3_free]. ** Hence, if this variable is modified directly, either it should be ** made NULL or made to point to memory obtained from [sqlite3_malloc] ** or else the use of the [temp_store_directory pragma] should be avoided. */ SQLITE_EXTERN char *sqlite3_temp_directory; /* ** CAPI3REF: Test For Auto-Commit Mode {H12930} ** KEYWORDS: {autocommit mode} ** ** The sqlite3_get_autocommit() interface returns non-zero or ** zero if the given database connection is or is not in autocommit mode, ** respectively. Autocommit mode is on by default. ** Autocommit mode is disabled by a [BEGIN] statement. ** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK]. ** ** If certain kinds of errors occur on a statement within a multi-statement ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR], ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the ** transaction might be rolled back automatically. The only way to ** find out whether SQLite automatically rolled back the transaction after ** an error is to use this function. ** ** If another thread changes the autocommit status of the database ** connection while this routine is running, then the return value ** is undefined. ** ** Requirements: [H12931] [H12932] [H12933] [H12934] */ int sqlite3_get_autocommit(sqlite3*); /* ** CAPI3REF: Find The Database Handle Of A Prepared Statement {H13120} ** ** The sqlite3_db_handle interface returns the [database connection] handle ** to which a [prepared statement] belongs. The [database connection] ** returned by sqlite3_db_handle is the same [database connection] that was the first argument ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to ** create the statement in the first place. ** ** Requirements: [H13123] */ sqlite3 *sqlite3_db_handle(sqlite3_stmt*); /* ** CAPI3REF: Find the next prepared statement {H13140} ** ** This interface returns a pointer to the next [prepared statement] after ** pStmt associated with the [database connection] pDb. If pStmt is NULL ** then this interface returns a pointer to the first prepared statement ** associated with the database connection pDb. If no prepared statement ** satisfies the conditions of this routine, it returns NULL. ** ** The [database connection] pointer D in a call to ** [sqlite3_next_stmt(D,S)] must refer to an open database ** connection and in particular must not be a NULL pointer. ** ** Requirements: [H13143] [H13146] [H13149] [H13152] */ sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt); /* ** CAPI3REF: Commit And Rollback Notification Callbacks {H12950} ** ** The sqlite3_commit_hook() interface registers a callback ** function to be invoked whenever a transaction is committed. ** Any callback set by a previous call to sqlite3_commit_hook() ** for the same database connection is overridden. ** The sqlite3_rollback_hook() interface registers a callback ** function to be invoked whenever a transaction is committed. ** Any callback set by a previous call to sqlite3_commit_hook() ** for the same database connection is overridden. ** The pArg argument is passed through to the callback. ** If the callback on a commit hook function returns non-zero, ** then the commit is converted into a rollback. ** ** If another function was previously registered, its ** pArg value is returned. Otherwise NULL is returned. ** ** The callback implementation must not do anything that will modify ** the database connection that invoked the callback. Any actions ** to modify the database connection must be deferred until after the ** completion of the [sqlite3_step()] call that triggered the commit ** or rollback hook in the first place. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** Registering a NULL function disables the callback. ** ** For the purposes of this API, a transaction is said to have been ** rolled back if an explicit "ROLLBACK" statement is executed, or ** an error or constraint causes an implicit rollback to occur. ** The rollback callback is not invoked if a transaction is ** automatically rolled back because the database connection is closed. ** The rollback callback is not invoked if a transaction is ** rolled back because a commit callback returned non-zero. ** Check on this ** ** Requirements: ** [H12951] [H12952] [H12953] [H12954] [H12955] ** [H12961] [H12962] [H12963] [H12964] */ void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*); void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*); /* ** CAPI3REF: Data Change Notification Callbacks {H12970} ** ** The sqlite3_update_hook() interface registers a callback function ** with the [database connection] identified by the first argument ** to be invoked whenever a row is updated, inserted or deleted. ** Any callback set by a previous call to this function ** for the same database connection is overridden. ** ** The second argument is a pointer to the function to invoke when a ** row is updated, inserted or deleted. ** The first argument to the callback is a copy of the third argument ** to sqlite3_update_hook(). ** The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE], ** or [SQLITE_UPDATE], depending on the operation that caused the callback ** to be invoked. ** The third and fourth arguments to the callback contain pointers to the ** database and table name containing the affected row. ** The final callback parameter is the [rowid] of the row. ** In the case of an update, this is the [rowid] after the update takes place. ** ** The update hook is not invoked when internal system tables are ** modified (i.e. sqlite_master and sqlite_sequence). ** ** The update hook implementation must not do anything that will modify ** the database connection that invoked the update hook. Any actions ** to modify the database connection must be deferred until after the ** completion of the [sqlite3_step()] call that triggered the update hook. ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their ** database connections for the meaning of "modify" in this paragraph. ** ** If another function was previously registered, its pArg value ** is returned. Otherwise NULL is returned. ** ** Requirements: ** [H12971] [H12973] [H12975] [H12977] [H12979] [H12981] [H12983] [H12986] */ void *sqlite3_update_hook( sqlite3*, void(*)(void *,int ,char const *,char const *,sqlite3_int64), void* ); /* ** CAPI3REF: Enable Or Disable Shared Pager Cache {H10330} ** KEYWORDS: {shared cache} {shared cache mode} ** ** This routine enables or disables the sharing of the database cache ** and schema data structures between [database connection | connections] ** to the same database. Sharing is enabled if the argument is true ** and disabled if the argument is false. ** ** Cache sharing is enabled and disabled for an entire process. ** This is a change as of SQLite version 3.5.0. In prior versions of SQLite, ** sharing was enabled or disabled for each thread separately. ** ** The cache sharing mode set by this interface effects all subsequent ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()]. ** Existing database connections continue use the sharing mode ** that was in effect at the time they were opened. ** ** Virtual tables cannot be used with a shared cache. When shared ** cache is enabled, the [sqlite3_create_module()] API used to register ** virtual tables will always return an error. ** ** This routine returns [SQLITE_OK] if shared cache was enabled or disabled ** successfully. An [error code] is returned otherwise. ** ** Shared cache is disabled by default. But this might change in ** future releases of SQLite. Applications that care about shared ** cache setting should set it explicitly. ** ** See Also: [SQLite Shared-Cache Mode] ** ** Requirements: [H10331] [H10336] [H10337] [H10339] */ int sqlite3_enable_shared_cache(int); /* ** CAPI3REF: Attempt To Free Heap Memory {H17340} ** ** The sqlite3_release_memory() interface attempts to free N bytes ** of heap memory by deallocating non-essential memory allocations ** held by the database library. {END} Memory used to cache database ** pages to improve performance is an example of non-essential memory. ** sqlite3_release_memory() returns the number of bytes actually freed, ** which might be more or less than the amount requested. ** ** Requirements: [H17341] [H17342] */ int sqlite3_release_memory(int); /* ** CAPI3REF: Impose A Limit On Heap Size {H17350} ** ** The sqlite3_soft_heap_limit() interface places a "soft" limit ** on the amount of heap memory that may be allocated by SQLite. ** If an internal allocation is requested that would exceed the ** soft heap limit, [sqlite3_release_memory()] is invoked one or ** more times to free up some space before the allocation is performed. ** ** The limit is called "soft", because if [sqlite3_release_memory()] ** cannot free sufficient memory to prevent the limit from being exceeded, ** the memory is allocated anyway and the current operation proceeds. ** ** A negative or zero value for N means that there is no soft heap limit and ** [sqlite3_release_memory()] will only be called when memory is exhausted. ** The default value for the soft heap limit is zero. ** ** SQLite makes a best effort to honor the soft heap limit. ** But if the soft heap limit cannot be honored, execution will ** continue without error or notification. This is why the limit is ** called a "soft" limit. It is advisory only. ** ** Prior to SQLite version 3.5.0, this routine only constrained the memory ** allocated by a single thread - the same thread in which this routine ** runs. Beginning with SQLite version 3.5.0, the soft heap limit is ** applied to all threads. The value specified for the soft heap limit ** is an upper bound on the total memory allocation for all threads. In ** version 3.5.0 there is no mechanism for limiting the heap usage for ** individual threads. ** ** Requirements: ** [H16351] [H16352] [H16353] [H16354] [H16355] [H16358] */ void sqlite3_soft_heap_limit(int); /* ** CAPI3REF: Extract Metadata About A Column Of A Table {H12850} ** ** This routine returns metadata about a specific column of a specific ** database table accessible using the [database connection] handle ** passed as the first function argument. ** ** The column is identified by the second, third and fourth parameters to ** this function. The second parameter is either the name of the database ** (i.e. "main", "temp" or an attached database) containing the specified ** table or NULL. If it is NULL, then all attached databases are searched ** for the table using the same algorithm used by the database engine to ** resolve unqualified table references. ** ** The third and fourth parameters to this function are the table and column ** name of the desired column, respectively. Neither of these parameters ** may be NULL. ** ** Metadata is returned by writing to the memory locations passed as the 5th ** and subsequent parameters to this function. Any of these arguments may be ** NULL, in which case the corresponding element of metadata is omitted. ** **
** **
Parameter Output
Type 		Description ** **
5th const char* Data type **
6th const char* Name of default collation sequence **
7th int True if column has a NOT NULL constraint **
8th int True if column is part of the PRIMARY KEY **
9th int True if column is [AUTOINCREMENT] **
**
** ** The memory pointed to by the character pointers returned for the ** declaration type and collation sequence is valid only until the next ** call to any SQLite API function. ** ** If the specified table is actually a view, an [error code] is returned. ** ** If the specified column is "rowid", "oid" or "_rowid_" and an ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output ** parameters are set for the explicitly declared column. If there is no ** explicitly declared [INTEGER PRIMARY KEY] column, then the output ** parameters are set as follows: ** ** 
**     data type: "INTEGER"
**     collation sequence: "BINARY"
**     not null: 0
**     primary key: 1
**     auto increment: 0
**
** ** This function may load one or more schemas from database files. If an ** error occurs during this process, or if the requested table or column ** cannot be found, an [error code] is returned and an error message left ** in the [database connection] (to be retrieved using sqlite3_errmsg()). ** ** This API is only available if the library was compiled with the ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol defined. */ int sqlite3_table_column_metadata( sqlite3 *db, /* Connection handle */ const char *zDbName, /* Database name or NULL */ const char *zTableName, /* Table name */ const char *zColumnName, /* Column name */ char const **pzDataType, /* OUTPUT: Declared data type */ char const **pzCollSeq, /* OUTPUT: Collation sequence name */ int *pNotNull, /* OUTPUT: True if NOT NULL constraint exists */ int *pPrimaryKey, /* OUTPUT: True if column part of PK */ int *pAutoinc /* OUTPUT: True if column is auto-increment */ ); /* ** CAPI3REF: Load An Extension {H12600} ** ** This interface loads an SQLite extension library from the named file. ** ** {H12601} The sqlite3_load_extension() interface attempts to load an ** SQLite extension library contained in the file zFile. ** ** {H12602} The entry point is zProc. ** ** {H12603} zProc may be 0, in which case the name of the entry point ** defaults to "sqlite3_extension_init". ** ** {H12604} The sqlite3_load_extension() interface shall return ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong. ** ** {H12605} If an error occurs and pzErrMsg is not 0, then the ** [sqlite3_load_extension()] interface shall attempt to ** fill *pzErrMsg with error message text stored in memory ** obtained from [sqlite3_malloc()]. {END} The calling function ** should free this memory by calling [sqlite3_free()]. ** ** {H12606} Extension loading must be enabled using ** [sqlite3_enable_load_extension()] prior to calling this API, ** otherwise an error will be returned. */ int sqlite3_load_extension( sqlite3 *db, /* Load the extension into this database connection */ const char *zFile, /* Name of the shared library containing extension */ const char *zProc, /* Entry point. Derived from zFile if 0 */ char **pzErrMsg /* Put error message here if not 0 */ ); /* ** CAPI3REF: Enable Or Disable Extension Loading {H12620} ** ** So as not to open security holes in older applications that are ** unprepared to deal with extension loading, and as a means of disabling ** extension loading while evaluating user-entered SQL, the following API ** is provided to turn the [sqlite3_load_extension()] mechanism on and off. ** ** Extension loading is off by default. See ticket #1863. ** ** {H12621} Call the sqlite3_enable_load_extension() routine with onoff==1 ** to turn extension loading on and call it with onoff==0 to turn ** it back off again. ** ** {H12622} Extension loading is off by default. */ int sqlite3_enable_load_extension(sqlite3 *db, int onoff); /* ** CAPI3REF: Automatically Load An Extensions {H12640} ** ** This API can be invoked at program startup in order to register ** one or more statically linked extensions that will be available ** to all new [database connections]. {END} ** ** This routine stores a pointer to the extension in an array that is ** obtained from [sqlite3_malloc()]. If you run a memory leak checker ** on your program and it reports a leak because of this array, invoke ** [sqlite3_reset_auto_extension()] prior to shutdown to free the memory. ** ** {H12641} This function registers an extension entry point that is ** automatically invoked whenever a new [database connection] ** is opened using [sqlite3_open()], [sqlite3_open16()], ** or [sqlite3_open_v2()]. ** ** {H12642} Duplicate extensions are detected so calling this routine ** multiple times with the same extension is harmless. ** ** {H12643} This routine stores a pointer to the extension in an array ** that is obtained from [sqlite3_malloc()]. ** ** {H12644} Automatic extensions apply across all threads. */ int sqlite3_auto_extension(void (*xEntryPoint)(void)); /* ** CAPI3REF: Reset Automatic Extension Loading {H12660} ** ** This function disables all previously registered automatic ** extensions. {END} It undoes the effect of all prior ** [sqlite3_auto_extension()] calls. ** ** {H12661} This function disables all previously registered ** automatic extensions. ** ** {H12662} This function disables automatic extensions in all threads. */ void sqlite3_reset_auto_extension(void); /* ****** EXPERIMENTAL - subject to change without notice ************** ** ** The interface to the virtual-table mechanism is currently considered ** to be experimental. The interface might change in incompatible ways. ** If this is a problem for you, do not use the interface at this time. ** ** When the virtual-table mechanism stabilizes, we will declare the ** interface fixed, support it indefinitely, and remove this comment. */ /* ** Structures used by the virtual table interface */ typedef struct sqlite3_vtab sqlite3_vtab; typedef struct sqlite3_index_info sqlite3_index_info; typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor; typedef struct sqlite3_module sqlite3_module; /* ** CAPI3REF: Virtual Table Object {H18000} ** KEYWORDS: sqlite3_module ** EXPERIMENTAL ** ** A module is a class of virtual tables. Each module is defined ** by an instance of the following structure. This structure consists ** mostly of methods for the module. ** ** This interface is experimental and is subject to change or ** removal in future releases of SQLite. */ struct sqlite3_module { int iVersion; int (*xCreate)(sqlite3*, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char**); int (*xConnect)(sqlite3*, void *pAux, int argc, const char *const*argv, sqlite3_vtab **ppVTab, char**); int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*); int (*xDisconnect)(sqlite3_vtab *pVTab); int (*xDestroy)(sqlite3_vtab *pVTab); int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor); int (*xClose)(sqlite3_vtab_cursor*); int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr, int argc, sqlite3_value **argv); int (*xNext)(sqlite3_vtab_cursor*); int (*xEof)(sqlite3_vtab_cursor*); int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int); int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid); int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *); int (*xBegin)(sqlite3_vtab *pVTab); int (*xSync)(sqlite3_vtab *pVTab); int (*xCommit)(sqlite3_vtab *pVTab); int (*xRollback)(sqlite3_vtab *pVTab); int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName, void (**pxFunc)(sqlite3_context*,int,sqlite3_value**), void **ppArg); int (*xRename)(sqlite3_vtab *pVtab, const char *zNew); }; /* ** CAPI3REF: Virtual Table Indexing Information {H18100} ** KEYWORDS: sqlite3_index_info ** EXPERIMENTAL ** ** The sqlite3_index_info structure and its substructures is used to ** pass information into and receive the reply from the xBestIndex ** method of an sqlite3_module. The fields under **Inputs** are the ** inputs to xBestIndex and are read-only. xBestIndex inserts its ** results into the **Outputs** fields. ** ** The aConstraint[] array records WHERE clause constraints of the form: ** ** 
column OP expr
** ** where OP is =, <, <=, >, or >=. The particular operator is ** stored in aConstraint[].op. The index of the column is stored in ** aConstraint[].iColumn. aConstraint[].usable is TRUE if the ** expr on the right-hand side can be evaluated (and thus the constraint ** is usable) and false if it cannot. ** ** The optimizer automatically inverts terms of the form "expr OP column" ** and makes other simplifications to the WHERE clause in an attempt to ** get as many WHERE clause terms into the form shown above as possible. ** The aConstraint[] array only reports WHERE clause terms in the correct ** form that refer to the particular virtual table being queried. ** ** Information about the ORDER BY clause is stored in aOrderBy[]. ** Each term of aOrderBy records a column of the ORDER BY clause. ** ** The xBestIndex method must fill aConstraintUsage[] with information ** about what parameters to pass to xFilter. If argvIndex>0 then ** the right-hand side of the corresponding aConstraint[] is evaluated ** and becomes the argvIndex-th entry in argv. If aConstraintUsage[].omit ** is true, then the constraint is assumed to be fully handled by the ** virtual table and is not checked again by SQLite. ** ** The idxNum and idxPtr values are recorded and passed into xFilter. ** sqlite3_free() is used to free idxPtr if needToFreeIdxPtr is true. ** ** The orderByConsumed means that output from xFilter will occur in ** the correct order to satisfy the ORDER BY clause so that no separate ** sorting step is required. ** ** The estimatedCost value is an estimate of the cost of doing the ** particular lookup. A full scan of a table with N entries should have ** a cost of N. A binary search of a table of N entries should have a ** cost of approximately log(N). ** ** This interface is experimental and is subject to change or ** removal in future releases of SQLite. */ struct sqlite3_index_info { /* Inputs */ int nConstraint; /* Number of entries in aConstraint */ struct sqlite3_index_constraint { int iColumn; /* Column on left-hand side of constraint */ unsigned char op; /* Constraint operator */ unsigned char usable; /* True if this constraint is usable */ int iTermOffset; /* Used internally - xBestIndex should ignore */ } *aConstraint; /* Table of WHERE clause constraints */ int nOrderBy; /* Number of terms in the ORDER BY clause */ struct sqlite3_index_orderby { int iColumn; /* Column number */ unsigned char desc; /* True for DESC. False for ASC. */ } *aOrderBy; /* The ORDER BY clause */ /* Outputs */ struct sqlite3_index_constraint_usage { int argvIndex; /* if >0, constraint is part of argv to xFilter */ unsigned char omit; /* Do not code a test for this constraint */ } *aConstraintUsage; int idxNum; /* Number used to identify the index */ char *idxStr; /* String, possibly obtained from sqlite3_malloc */ int needToFreeIdxStr; /* Free idxStr using sqlite3_free() if true */ int orderByConsumed; /* True if output is already ordered */ double estimatedCost; /* Estimated cost of using this index */ }; #define SQLITE_INDEX_CONSTRAINT_EQ 2 #define SQLITE_INDEX_CONSTRAINT_GT 4 #define SQLITE_INDEX_CONSTRAINT_LE 8 #define SQLITE_INDEX_CONSTRAINT_LT 16 #define SQLITE_INDEX_CONSTRAINT_GE 32 #define SQLITE_INDEX_CONSTRAINT_MATCH 64 /* ** CAPI3REF: Register A Virtual Table Implementation {H18200} ** EXPERIMENTAL ** ** This routine is used to register a new module name with a ** [database connection]. Module names must be registered before ** creating new virtual tables on the module, or before using ** preexisting virtual tables of the module. ** ** This interface is experimental and is subject to change or ** removal in future releases of SQLite. */ SQLITE_EXPERIMENTAL int sqlite3_create_module( sqlite3 *db, /* SQLite connection to register module with */ const char *zName, /* Name of the module */ const sqlite3_module *, /* Methods for the module */ void * /* Client data for xCreate/xConnect */ ); /* ** CAPI3REF: Register A Virtual Table Implementation {H18210} ** EXPERIMENTAL ** ** This routine is identical to the [sqlite3_create_module()] method above, ** except that it allows a destructor function to be specified. It is ** even more experimental than the rest of the virtual tables API. */ SQLITE_EXPERIMENTAL int sqlite3_create_module_v2( sqlite3 *db, /* SQLite connection to register module with */ const char *zName, /* Name of the module */ const sqlite3_module *, /* Methods for the module */ void *, /* Client data for xCreate/xConnect */ void(*xDestroy)(void*) /* Module destructor function */ ); /* ** CAPI3REF: Virtual Table Instance Object {H18010} ** KEYWORDS: sqlite3_vtab ** EXPERIMENTAL ** ** Every module implementation uses a subclass of the following structure ** to describe a particular instance of the module. Each subclass will ** be tailored to the specific needs of the module implementation. ** The purpose of this superclass is to define certain fields that are ** common to all module implementations. ** ** Virtual tables methods can set an error message by assigning a ** string obtained from [sqlite3_mprintf()] to zErrMsg. The method should ** take care that any prior string is freed by a call to [sqlite3_free()] ** prior to assigning a new string to zErrMsg. After the error message ** is delivered up to the client application, the string will be automatically ** freed by sqlite3_free() and the zErrMsg field will be zeroed. Note ** that sqlite3_mprintf() and sqlite3_free() are used on the zErrMsg field ** since virtual tables are commonly implemented in loadable extensions which ** do not have access to sqlite3MPrintf() or sqlite3Free(). ** ** This interface is experimental and is subject to change or ** removal in future releases of SQLite. */ struct sqlite3_vtab { const sqlite3_module *pModule; /* The module for this virtual table */ int nRef; /* Used internally */ char *zErrMsg; /* Error message from sqlite3_mprintf() */ /* Virtual table implementations will typically add additional fields */ }; /* ** CAPI3REF: Virtual Table Cursor Object {H18020} ** KEYWORDS: sqlite3_vtab_cursor ** EXPERIMENTAL ** ** Every module implementation uses a subclass of the following structure ** to describe cursors that point into the virtual table and are used ** to loop through the virtual table. Cursors are created using the ** xOpen method of the module. Each module implementation will define ** the content of a cursor structure to suit its own needs. ** ** This superclass exists in order to define fields of the cursor that ** are common to all implementations. ** ** This interface is experimental and is subject to change or ** removal in future releases of SQLite. */ struct sqlite3_vtab_cursor { sqlite3_vtab *pVtab; /* Virtual table of this cursor */ /* Virtual table implementations will typically add additional fields */ }; /* ** CAPI3REF: Declare The Schema Of A Virtual Table {H18280} ** EXPERIMENTAL ** ** The xCreate and xConnect methods of a module use the following API ** to declare the format (the names and datatypes of the columns) of ** the virtual tables they implement. ** ** This interface is experimental and is subject to change or ** removal in future releases of SQLite. */ SQLITE_EXPERIMENTAL int sqlite3_declare_vtab(sqlite3*, const char *zCreateTable); /* ** CAPI3REF: Overload A Function For A Virtual Table {H18300} ** EXPERIMENTAL ** ** Virtual tables can provide alternative implementations of functions ** using the xFindFunction method. But global versions of those functions ** must exist in order to be overloaded. ** ** This API makes sure a global version of a function with a particular ** name and number of parameters exists. If no such function exists ** before this API is called, a new function is created. The implementation ** of the new function always causes an exception to be thrown. So ** the new function is not good for anything by itself. Its only ** purpose is to be a placeholder function that can be overloaded ** by virtual tables. ** ** This API should be considered part of the virtual table interface, ** which is experimental and subject to change. */ SQLITE_EXPERIMENTAL int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg); /* ** The interface to the virtual-table mechanism defined above (back up ** to a comment remarkably similar to this one) is currently considered ** to be experimental. The interface might change in incompatible ways. ** If this is a problem for you, do not use the interface at this time. ** ** When the virtual-table mechanism stabilizes, we will declare the ** interface fixed, support it indefinitely, and remove this comment. ** ****** EXPERIMENTAL - subject to change without notice ************** */ /* ** CAPI3REF: A Handle To An Open BLOB {H17800} ** KEYWORDS: {BLOB handle} {BLOB handles} ** ** An instance of this object represents an open BLOB on which ** [sqlite3_blob_open | incremental BLOB I/O] can be performed. ** Objects of this type are created by [sqlite3_blob_open()] ** and destroyed by [sqlite3_blob_close()]. ** The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces ** can be used to read or write small subsections of the BLOB. ** The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes. */ typedef struct sqlite3_blob sqlite3_blob; /* ** CAPI3REF: Open A BLOB For Incremental I/O {H17810} ** ** This interfaces opens a [BLOB handle | handle] to the BLOB located ** in row iRow, column zColumn, table zTable in database zDb; ** in other words, the same BLOB that would be selected by: ** ** 
**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
**
{END} ** ** If the flags parameter is non-zero, the the BLOB is opened for read ** and write access. If it is zero, the BLOB is opened for read access. ** ** Note that the database name is not the filename that contains ** the database but rather the symbolic name of the database that ** is assigned when the database is connected using [ATTACH]. ** For the main database file, the database name is "main". ** For TEMP tables, the database name is "temp". ** ** On success, [SQLITE_OK] is returned and the new [BLOB handle] is written ** to *ppBlob. Otherwise an [error code] is returned and any value written ** to *ppBlob should not be used by the caller. ** This function sets the [database connection] error code and message ** accessible via [sqlite3_errcode()] and [sqlite3_errmsg()]. ** ** If the row that a BLOB handle points to is modified by an ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects ** then the BLOB handle is marked as "expired". ** This is true if any column of the row is changed, even a column ** other than the one the BLOB handle is open on. ** Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for ** a expired BLOB handle fail with an return code of [SQLITE_ABORT]. ** Changes written into a BLOB prior to the BLOB expiring are not ** rollback by the expiration of the BLOB. Such changes will eventually ** commit if the transaction continues to completion. ** ** Requirements: ** [H17813] [H17814] [H17816] [H17819] [H17821] [H17824] */ int sqlite3_blob_open( sqlite3*, const char *zDb, const char *zTable, const char *zColumn, sqlite3_int64 iRow, int flags, sqlite3_blob **ppBlob ); /* ** CAPI3REF: Close A BLOB Handle {H17830} ** ** Closes an open [BLOB handle]. ** ** Closing a BLOB shall cause the current transaction to commit ** if there are no other BLOBs, no pending prepared statements, and the ** database connection is in [autocommit mode]. ** If any writes were made to the BLOB, they might be held in cache ** until the close operation if they will fit. {END} ** ** Closing the BLOB often forces the changes ** out to disk and so if any I/O errors occur, they will likely occur ** at the time when the BLOB is closed. {H17833} Any errors that occur during ** closing are reported as a non-zero return value. ** ** The BLOB is closed unconditionally. Even if this routine returns ** an error code, the BLOB is still closed. ** ** Requirements: ** [H17833] [H17836] [H17839] */ int sqlite3_blob_close(sqlite3_blob *); /* ** CAPI3REF: Return The Size Of An Open BLOB {H17840} ** ** Returns the size in bytes of the BLOB accessible via the open ** []BLOB handle] in its only argument. ** ** Requirements: ** [H17843] */ int sqlite3_blob_bytes(sqlite3_blob *); /* ** CAPI3REF: Read Data From A BLOB Incrementally {H17850} ** ** This function is used to read data from an open [BLOB handle] into a ** caller-supplied buffer. N bytes of data are copied into buffer Z ** from the open BLOB, starting at offset iOffset. ** ** If offset iOffset is less than N bytes from the end of the BLOB, ** [SQLITE_ERROR] is returned and no data is read. If N or iOffset is ** less than zero, [SQLITE_ERROR] is returned and no data is read. ** ** An attempt to read from an expired [BLOB handle] fails with an ** error code of [SQLITE_ABORT]. ** ** On success, SQLITE_OK is returned. ** Otherwise, an [error code] or an [extended error code] is returned. ** ** Requirements: ** [H17853] [H17856] [H17859] [H17862] [H17863] [H17865] [H17868] */ int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset); /* ** CAPI3REF: Write Data Into A BLOB Incrementally {H17870} ** ** This function is used to write data into an open [BLOB handle] from a ** caller-supplied buffer. N bytes of data are copied from the buffer Z ** into the open BLOB, starting at offset iOffset. ** ** If the [BLOB handle] passed as the first argument was not opened for ** writing (the flags parameter to [sqlite3_blob_open()] was zero), ** this function returns [SQLITE_READONLY]. ** ** This function may only modify the contents of the BLOB; it is ** not possible to increase the size of a BLOB using this API. ** If offset iOffset is less than N bytes from the end of the BLOB, ** [SQLITE_ERROR] is returned and no data is written. If N is ** less than zero [SQLITE_ERROR] is returned and no data is written. ** ** An attempt to write to an expired [BLOB handle] fails with an ** error code of [SQLITE_ABORT]. Writes to the BLOB that occurred ** before the [BLOB handle] expired are not rolled back by the ** expiration of the handle, though of course those changes might ** have been overwritten by the statement that expired the BLOB handle ** or by other independent statements. ** ** On success, SQLITE_OK is returned. ** Otherwise, an [error code] or an [extended error code] is returned. ** ** Requirements: ** [H17873] [H17874] [H17875] [H17876] [H17877] [H17879] [H17882] [H17885] ** [H17888] */ int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset); /* ** CAPI3REF: Virtual File System Objects {H11200} ** ** A virtual filesystem (VFS) is an [sqlite3_vfs] object ** that SQLite uses to interact ** with the underlying operating system. Most SQLite builds come with a ** single default VFS that is appropriate for the host computer. ** New VFSes can be registered and existing VFSes can be unregistered. ** The following interfaces are provided. ** ** The sqlite3_vfs_find() interface returns a pointer to a VFS given its name. ** Names are case sensitive. ** Names are zero-terminated UTF-8 strings. ** If there is no match, a NULL pointer is returned. ** If zVfsName is NULL then the default VFS is returned. ** ** New VFSes are registered with sqlite3_vfs_register(). ** Each new VFS becomes the default VFS if the makeDflt flag is set. ** The same VFS can be registered multiple times without injury. ** To make an existing VFS into the default VFS, register it again ** with the makeDflt flag set. If two different VFSes with the ** same name are registered, the behavior is undefined. If a ** VFS is registered with a name that is NULL or an empty string, ** then the behavior is undefined. ** ** Unregister a VFS with the sqlite3_vfs_unregister() interface. ** If the default VFS is unregistered, another VFS is chosen as ** the default. The choice for the new VFS is arbitrary. ** ** Requirements: ** [H11203] [H11206] [H11209] [H11212] [H11215] [H11218] */ sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName); int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt); int sqlite3_vfs_unregister(sqlite3_vfs*); /* ** CAPI3REF: Mutexes {H17000} ** ** The SQLite core uses these routines for thread ** synchronization. Though they are intended for internal ** use by SQLite, code that links against SQLite is ** permitted to use any of these routines. ** ** The SQLite source code contains multiple implementations ** of these mutex routines. An appropriate implementation ** is selected automatically at compile-time. The following ** implementations are available in the SQLite core: ** **
    **
  • SQLITE_MUTEX_OS2 **
  • SQLITE_MUTEX_PTHREAD **
  • SQLITE_MUTEX_W32 **
  • SQLITE_MUTEX_NOOP **
** ** The SQLITE_MUTEX_NOOP implementation is a set of routines ** that does no real locking and is appropriate for use in ** a single-threaded application. The SQLITE_MUTEX_OS2, ** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations ** are appropriate for use on OS/2, Unix, and Windows. ** ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex ** implementation is included with the library. In this case the ** application must supply a custom mutex implementation using the ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function ** before calling sqlite3_initialize() or any other public sqlite3_ ** function that calls sqlite3_initialize(). ** ** {H17011} The sqlite3_mutex_alloc() routine allocates a new ** mutex and returns a pointer to it. {H17012} If it returns NULL ** that means that a mutex could not be allocated. {H17013} SQLite ** will unwind its stack and return an error. {H17014} The argument ** to sqlite3_mutex_alloc() is one of these integer constants: ** **
    **
  • SQLITE_MUTEX_FAST **
  • SQLITE_MUTEX_RECURSIVE **
  • SQLITE_MUTEX_STATIC_MASTER **
  • SQLITE_MUTEX_STATIC_MEM **
  • SQLITE_MUTEX_STATIC_MEM2 **
  • SQLITE_MUTEX_STATIC_PRNG **
  • SQLITE_MUTEX_STATIC_LRU **
  • SQLITE_MUTEX_STATIC_LRU2 **
** ** {H17015} The first two constants cause sqlite3_mutex_alloc() to create ** a new mutex. The new mutex is recursive when SQLITE_MUTEX_RECURSIVE ** is used but not necessarily so when SQLITE_MUTEX_FAST is used. {END} ** The mutex implementation does not need to make a distinction ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does ** not want to. {H17016} But SQLite will only request a recursive mutex in ** cases where it really needs one. {END} If a faster non-recursive mutex ** implementation is available on the host platform, the mutex subsystem ** might return such a mutex in response to SQLITE_MUTEX_FAST. ** ** {H17017} The other allowed parameters to sqlite3_mutex_alloc() each return ** a pointer to a static preexisting mutex. {END} Four static mutexes are ** used by the current version of SQLite. Future versions of SQLite ** may add additional static mutexes. Static mutexes are for internal ** use by SQLite only. Applications that use SQLite mutexes should ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or ** SQLITE_MUTEX_RECURSIVE. ** ** {H17018} Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc() ** returns a different mutex on every call. {H17034} But for the static ** mutex types, the same mutex is returned on every call that has ** the same type number. ** ** {H17019} The sqlite3_mutex_free() routine deallocates a previously ** allocated dynamic mutex. {H17020} SQLite is careful to deallocate every ** dynamic mutex that it allocates. {A17021} The dynamic mutexes must not be in ** use when they are deallocated. {A17022} Attempting to deallocate a static ** mutex results in undefined behavior. {H17023} SQLite never deallocates ** a static mutex. {END} ** ** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt ** to enter a mutex. {H17024} If another thread is already within the mutex, ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return ** SQLITE_BUSY. {H17025} The sqlite3_mutex_try() interface returns [SQLITE_OK] ** upon successful entry. {H17026} Mutexes created using ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread. ** {H17027} In such cases the, ** mutex must be exited an equal number of times before another thread ** can enter. {A17028} If the same thread tries to enter any other ** kind of mutex more than once, the behavior is undefined. ** {H17029} SQLite will never exhibit ** such behavior in its own use of mutexes. ** ** Some systems (for example, Windows 95) do not support the operation ** implemented by sqlite3_mutex_try(). On those systems, sqlite3_mutex_try() ** will always return SQLITE_BUSY. {H17030} The SQLite core only ever uses ** sqlite3_mutex_try() as an optimization so this is acceptable behavior. ** ** {H17031} The sqlite3_mutex_leave() routine exits a mutex that was ** previously entered by the same thread. {A17032} The behavior ** is undefined if the mutex is not currently entered by the ** calling thread or is not currently allocated. {H17033} SQLite will ** never do either. {END} ** ** If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or ** sqlite3_mutex_leave() is a NULL pointer, then all three routines ** behave as no-ops. ** ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()]. */ sqlite3_mutex *sqlite3_mutex_alloc(int); void sqlite3_mutex_free(sqlite3_mutex*); void sqlite3_mutex_enter(sqlite3_mutex*); int sqlite3_mutex_try(sqlite3_mutex*); void sqlite3_mutex_leave(sqlite3_mutex*); /* ** CAPI3REF: Mutex Methods Object {H17120} ** EXPERIMENTAL ** ** An instance of this structure defines the low-level routines ** used to allocate and use mutexes. ** ** Usually, the default mutex implementations provided by SQLite are ** sufficient, however the user has the option of substituting a custom ** implementation for specialized deployments or systems for which SQLite ** does not provide a suitable implementation. In this case, the user ** creates and populates an instance of this structure to pass ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option. ** Additionally, an instance of this structure can be used as an ** output variable when querying the system for the current mutex ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option. ** ** The xMutexInit method defined by this structure is invoked as ** part of system initialization by the sqlite3_initialize() function. ** {H17001} The xMutexInit routine shall be called by SQLite once for each ** effective call to [sqlite3_initialize()]. ** ** The xMutexEnd method defined by this structure is invoked as ** part of system shutdown by the sqlite3_shutdown() function. The ** implementation of this method is expected to release all outstanding ** resources obtained by the mutex methods implementation, especially ** those obtained by the xMutexInit method. {H17003} The xMutexEnd() ** interface shall be invoked once for each call to [sqlite3_shutdown()]. ** ** The remaining seven methods defined by this structure (xMutexAlloc, ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and ** xMutexNotheld) implement the following interfaces (respectively): ** **
    **
  • [sqlite3_mutex_alloc()]
    • **
  • [sqlite3_mutex_free()]
    • **
  • [sqlite3_mutex_enter()]
    • **
  • [sqlite3_mutex_try()]
    • **
  • [sqlite3_mutex_leave()]
    • **
  • [sqlite3_mutex_held()]
    • **
  • [sqlite3_mutex_notheld()]
    • **
** ** The only difference is that the public sqlite3_XXX functions enumerated ** above silently ignore any invocations that pass a NULL pointer instead ** of a valid mutex handle. The implementations of the methods defined ** by this structure are not required to handle this case, the results ** of passing a NULL pointer instead of a valid mutex handle are undefined ** (i.e. it is acceptable to provide an implementation that segfaults if ** it is passed a NULL pointer). */ typedef struct sqlite3_mutex_methods sqlite3_mutex_methods; struct sqlite3_mutex_methods { int (*xMutexInit)(void); int (*xMutexEnd)(void); sqlite3_mutex *(*xMutexAlloc)(int); void (*xMutexFree)(sqlite3_mutex *); void (*xMutexEnter)(sqlite3_mutex *); int (*xMutexTry)(sqlite3_mutex *); void (*xMutexLeave)(sqlite3_mutex *); int (*xMutexHeld)(sqlite3_mutex *); int (*xMutexNotheld)(sqlite3_mutex *); }; /* ** CAPI3REF: Mutex Verification Routines {H17080} ** ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines ** are intended for use inside assert() statements. {H17081} The SQLite core ** never uses these routines except inside an assert() and applications ** are advised to follow the lead of the core. {H17082} The core only ** provides implementations for these routines when it is compiled ** with the SQLITE_DEBUG flag. {A17087} External mutex implementations ** are only required to provide these routines if SQLITE_DEBUG is ** defined and if NDEBUG is not defined. ** ** {H17083} These routines should return true if the mutex in their argument ** is held or not held, respectively, by the calling thread. ** ** {X17084} The implementation is not required to provided versions of these ** routines that actually work. If the implementation does not provide working ** versions of these routines, it should at least provide stubs that always ** return true so that one does not get spurious assertion failures. ** ** {H17085} If the argument to sqlite3_mutex_held() is a NULL pointer then ** the routine should return 1. {END} This seems counter-intuitive since ** clearly the mutex cannot be held if it does not exist. But the ** the reason the mutex does not exist is because the build is not ** using mutexes. And we do not want the assert() containing the ** call to sqlite3_mutex_held() to fail, so a non-zero return is ** the appropriate thing to do. {H17086} The sqlite3_mutex_notheld() ** interface should also return 1 when given a NULL pointer. */ int sqlite3_mutex_held(sqlite3_mutex*); int sqlite3_mutex_notheld(sqlite3_mutex*); /* ** CAPI3REF: Mutex Types {H17001} ** ** The [sqlite3_mutex_alloc()] interface takes a single argument ** which is one of these integer constants. ** ** The set of static mutexes may change from one SQLite release to the ** next. Applications that override the built-in mutex logic must be ** prepared to accommodate additional static mutexes. */ #define SQLITE_MUTEX_FAST 0 #define SQLITE_MUTEX_RECURSIVE 1 #define SQLITE_MUTEX_STATIC_MASTER 2 #define SQLITE_MUTEX_STATIC_MEM 3 /* sqlite3_malloc() */ #define SQLITE_MUTEX_STATIC_MEM2 4 /* NOT USED */ #define SQLITE_MUTEX_STATIC_OPEN 4 /* sqlite3BtreeOpen() */ #define SQLITE_MUTEX_STATIC_PRNG 5 /* sqlite3_random() */ #define SQLITE_MUTEX_STATIC_LRU 6 /* lru page list */ #define SQLITE_MUTEX_STATIC_LRU2 7 /* lru page list */ /* ** CAPI3REF: Retrieve the mutex for a database connection {H17002} ** ** This interface returns a pointer the [sqlite3_mutex] object that ** serializes access to the [database connection] given in the argument ** when the [threading mode] is Serialized. ** If the [threading mode] is Single-thread or Multi-thread then this ** routine returns a NULL pointer. */ sqlite3_mutex *sqlite3_db_mutex(sqlite3*); /* ** CAPI3REF: Low-Level Control Of Database Files {H11300} ** ** {H11301} The [sqlite3_file_control()] interface makes a direct call to the ** xFileControl method for the [sqlite3_io_methods] object associated ** with a particular database identified by the second argument. {H11302} The ** name of the database is the name assigned to the database by the ** ATTACH SQL command that opened the ** database. {H11303} To control the main database file, use the name "main" ** or a NULL pointer. {H11304} The third and fourth parameters to this routine ** are passed directly through to the second and third parameters of ** the xFileControl method. {H11305} The return value of the xFileControl ** method becomes the return value of this routine. ** ** {H11306} If the second parameter (zDbName) does not match the name of any ** open database file, then SQLITE_ERROR is returned. {H11307} This error ** code is not remembered and will not be recalled by [sqlite3_errcode()] ** or [sqlite3_errmsg()]. {A11308} The underlying xFileControl method might ** also return SQLITE_ERROR. {A11309} There is no way to distinguish between ** an incorrect zDbName and an SQLITE_ERROR return from the underlying ** xFileControl method. {END} ** ** See also: [SQLITE_FCNTL_LOCKSTATE] */ int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*); /* ** CAPI3REF: Testing Interface {H11400} ** ** The sqlite3_test_control() interface is used to read out internal ** state of SQLite and to inject faults into SQLite for testing ** purposes. The first parameter is an operation code that determines ** the number, meaning, and operation of all subsequent parameters. ** ** This interface is not for use by applications. It exists solely ** for verifying the correct operation of the SQLite library. Depending ** on how the SQLite library is compiled, this interface might not exist. ** ** The details of the operation codes, their meanings, the parameters ** they take, and what they do are all subject to change without notice. ** Unlike most of the SQLite API, this function is not guaranteed to ** operate consistently from one release to the next. */ int sqlite3_test_control(int op, ...); /* ** CAPI3REF: Testing Interface Operation Codes {H11410} ** ** These constants are the valid operation code parameters used ** as the first argument to [sqlite3_test_control()]. ** ** These parameters and their meanings are subject to change ** without notice. These values are for testing purposes only. ** Applications should not use any of these parameters or the ** [sqlite3_test_control()] interface. */ #define SQLITE_TESTCTRL_PRNG_SAVE 5 #define SQLITE_TESTCTRL_PRNG_RESTORE 6 #define SQLITE_TESTCTRL_PRNG_RESET 7 #define SQLITE_TESTCTRL_BITVEC_TEST 8 #define SQLITE_TESTCTRL_FAULT_INSTALL 9 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS 10 #define SQLITE_TESTCTRL_PENDING_BYTE 11 /* ** CAPI3REF: SQLite Runtime Status {H17200} ** EXPERIMENTAL ** ** This interface is used to retrieve runtime status information ** about the preformance of SQLite, and optionally to reset various ** highwater marks. The first argument is an integer code for ** the specific parameter to measure. Recognized integer codes ** are of the form [SQLITE_STATUS_MEMORY_USED | SQLITE_STATUS_...]. ** The current value of the parameter is returned into *pCurrent. ** The highest recorded value is returned in *pHighwater. If the ** resetFlag is true, then the highest record value is reset after ** *pHighwater is written. Some parameters do not record the highest ** value. For those parameters ** nothing is written into *pHighwater and the resetFlag is ignored. ** Other parameters record only the highwater mark and not the current ** value. For these latter parameters nothing is written into *pCurrent. ** ** This routine returns SQLITE_OK on success and a non-zero ** [error code] on failure. ** ** This routine is threadsafe but is not atomic. This routine can ** called while other threads are running the same or different SQLite ** interfaces. However the values returned in *pCurrent and ** *pHighwater reflect the status of SQLite at different points in time ** and it is possible that another thread might change the parameter ** in between the times when *pCurrent and *pHighwater are written. ** ** See also: [sqlite3_db_status()] */ SQLITE_EXPERIMENTAL int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag); /* ** CAPI3REF: Status Parameters {H17250} ** EXPERIMENTAL ** ** These integer constants designate various run-time status parameters ** that can be returned by [sqlite3_status()]. ** **
**
SQLITE_STATUS_MEMORY_USED
**
This parameter is the current amount of memory checked out ** using [sqlite3_malloc()], either directly or indirectly. The ** figure includes calls made to [sqlite3_malloc()] by the application ** and internal memory usage by the SQLite library. Scratch memory ** controlled by [SQLITE_CONFIG_SCRATCH] and auxiliary page-cache ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in ** this parameter. The amount returned is the sum of the allocation ** sizes as reported by the xSize method in [sqlite3_mem_methods].
** **
SQLITE_STATUS_MALLOC_SIZE
**
This parameter records the largest memory allocation request ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their ** internal equivalents). Only the value returned in the ** *pHighwater parameter to [sqlite3_status()] is of interest. ** The value written into the *pCurrent parameter is undefined.
** **
SQLITE_STATUS_PAGECACHE_USED
**
This parameter returns the number of pages used out of the ** [pagecache memory allocator] that was configured using ** [SQLITE_CONFIG_PAGECACHE]. The ** value returned is in pages, not in bytes.
** **
SQLITE_STATUS_PAGECACHE_OVERFLOW
**
This parameter returns the number of bytes of page cache ** allocation which could not be statisfied by the [SQLITE_CONFIG_PAGECACHE] ** buffer and where forced to overflow to [sqlite3_malloc()]. The ** returned value includes allocations that overflowed because they ** where too large (they were larger than the "sz" parameter to ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because ** no space was left in the page cache.
** **
SQLITE_STATUS_PAGECACHE_SIZE
**
This parameter records the largest memory allocation request ** handed to [pagecache memory allocator]. Only the value returned in the ** *pHighwater parameter to [sqlite3_status()] is of interest. ** The value written into the *pCurrent parameter is undefined.
** **
SQLITE_STATUS_SCRATCH_USED
**
This parameter returns the number of allocations used out of the ** [scratch memory allocator] configured using ** [SQLITE_CONFIG_SCRATCH]. The value returned is in allocations, not ** in bytes. Since a single thread may only have one scratch allocation ** outstanding at time, this parameter also reports the number of threads ** using scratch memory at the same time.
** **
SQLITE_STATUS_SCRATCH_OVERFLOW
**
This parameter returns the number of bytes of scratch memory ** allocation which could not be statisfied by the [SQLITE_CONFIG_SCRATCH] ** buffer and where forced to overflow to [sqlite3_malloc()]. The values ** returned include overflows because the requested allocation was too ** larger (that is, because the requested allocation was larger than the ** "sz" parameter to [SQLITE_CONFIG_SCRATCH]) and because no scratch buffer ** slots were available. **
** **
SQLITE_STATUS_SCRATCH_SIZE
**
This parameter records the largest memory allocation request ** handed to [scratch memory allocator]. Only the value returned in the ** *pHighwater parameter to [sqlite3_status()] is of interest. ** The value written into the *pCurrent parameter is undefined.
** **
SQLITE_STATUS_PARSER_STACK
**
This parameter records the deepest parser stack. It is only ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].
**
** ** New status parameters may be added from time to time. */ #define SQLITE_STATUS_MEMORY_USED 0 #define SQLITE_STATUS_PAGECACHE_USED 1 #define SQLITE_STATUS_PAGECACHE_OVERFLOW 2 #define SQLITE_STATUS_SCRATCH_USED 3 #define SQLITE_STATUS_SCRATCH_OVERFLOW 4 #define SQLITE_STATUS_MALLOC_SIZE 5 #define SQLITE_STATUS_PARSER_STACK 6 #define SQLITE_STATUS_PAGECACHE_SIZE 7 #define SQLITE_STATUS_SCRATCH_SIZE 8 /* ** CAPI3REF: Database Connection Status {H17500} ** EXPERIMENTAL ** ** This interface is used to retrieve runtime status information ** about a single [database connection]. The first argument is the ** database connection object to be interrogated. The second argument ** is the parameter to interrogate. Currently, the only allowed value ** for the second parameter is [SQLITE_DBSTATUS_LOOKASIDE_USED]. ** Additional options will likely appear in future releases of SQLite. ** ** The current value of the requested parameter is written into *pCur ** and the highest instantaneous value is written into *pHiwtr. If ** the resetFlg is true, then the highest instantaneous value is ** reset back down to the current value. ** ** See also: [sqlite3_status()] and [sqlite3_stmt_status()]. */ SQLITE_EXPERIMENTAL int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg); /* ** CAPI3REF: Status Parameters for database connections {H17520} ** EXPERIMENTAL ** ** Status verbs for [sqlite3_db_status()]. ** **
**
SQLITE_DBSTATUS_LOOKASIDE_USED
**
This parameter returns the number of lookaside memory slots currently ** checked out.
**
*/ #define SQLITE_DBSTATUS_LOOKASIDE_USED 0 /* ** CAPI3REF: Prepared Statement Status {H17550} ** EXPERIMENTAL ** ** Each prepared statement maintains various ** [SQLITE_STMTSTATUS_SORT | counters] that measure the number ** of times it has performed specific operations. These counters can ** be used to monitor the performance characteristics of the prepared ** statements. For example, if the number of table steps greatly exceeds ** the number of table searches or result rows, that would tend to indicate ** that the prepared statement is using a full table scan rather than ** an index. ** ** This interface is used to retrieve and reset counter values from ** a [prepared statement]. The first argument is the prepared statement ** object to be interrogated. The second argument ** is an integer code for a specific [SQLITE_STMTSTATUS_SORT | counter] ** to be interrogated. ** The current value of the requested counter is returned. ** If the resetFlg is true, then the counter is reset to zero after this ** interface call returns. ** ** See also: [sqlite3_status()] and [sqlite3_db_status()]. */ SQLITE_EXPERIMENTAL int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg); /* ** CAPI3REF: Status Parameters for prepared statements {H17570} ** EXPERIMENTAL ** ** These preprocessor macros define integer codes that name counter ** values associated with the [sqlite3_stmt_status()] interface. ** The meanings of the various counters are as follows: ** **
**
SQLITE_STMTSTATUS_FULLSCAN_STEP
**
This is the number of times that SQLite has stepped forward in ** a table as part of a full table scan. Large numbers for this counter ** may indicate opportunities for performance improvement through ** careful use of indices.
** **
SQLITE_STMTSTATUS_SORT
**
This is the number of sort operations that have occurred. ** A non-zero value in this counter may indicate an opportunity to ** improvement performance through careful use of indices.
** **
*/ #define SQLITE_STMTSTATUS_FULLSCAN_STEP 1 #define SQLITE_STMTSTATUS_SORT 2 /* ** CAPI3REF: Custom Page Cache Object ** EXPERIMENTAL ** ** The sqlite3_pcache type is opaque. It is implemented by ** the pluggable module. The SQLite core has no knowledge of ** its size or internal structure and never deals with the ** sqlite3_pcache object except by holding and passing pointers ** to the object. ** ** See [sqlite3_pcache_methods] for additional information. */ typedef struct sqlite3_pcache sqlite3_pcache; /* ** CAPI3REF: Application Defined Page Cache. ** EXPERIMENTAL ** ** The [sqlite3_config]([SQLITE_CONFIG_PCACHE], ...) interface can ** register an alternative page cache implementation by passing in an ** instance of the sqlite3_pcache_methods structure. The majority of the ** heap memory used by sqlite is used by the page cache to cache data read ** from, or ready to be written to, the database file. By implementing a ** custom page cache using this API, an application can control more ** precisely the amount of memory consumed by sqlite, the way in which ** said memory is allocated and released, and the policies used to ** determine exactly which parts of a database file are cached and for ** how long. ** ** The contents of the structure are copied to an internal buffer by sqlite ** within the call to [sqlite3_config]. ** ** The xInit() method is called once for each call to [sqlite3_initialize()] ** (usually only once during the lifetime of the process). It is passed ** a copy of the sqlite3_pcache_methods.pArg value. It can be used to set ** up global structures and mutexes required by the custom page cache ** implementation. The xShutdown() method is called from within ** [sqlite3_shutdown()], if the application invokes this API. It can be used ** to clean up any outstanding resources before process shutdown, if required. ** ** The xCreate() method is used to construct a new cache instance. The ** first parameter, szPage, is the size in bytes of the pages that must ** be allocated by the cache. szPage will not be a power of two. The ** second argument, bPurgeable, is true if the cache being created will ** be used to cache database pages read from a file stored on disk, or ** false if it is used for an in-memory database. The cache implementation ** does not have to do anything special based on the value of bPurgeable, ** it is purely advisory. ** ** The xCachesize() method may be called at any time by SQLite to set the ** suggested maximum cache-size (number of pages stored by) the cache ** instance passed as the first argument. This is the value configured using ** the SQLite "[PRAGMA cache_size]" command. As with the bPurgeable parameter, ** the implementation is not required to do anything special with this ** value, it is advisory only. ** ** The xPagecount() method should return the number of pages currently ** stored in the cache supplied as an argument. ** ** The xFetch() method is used to fetch a page and return a pointer to it. ** A 'page', in this context, is a buffer of szPage bytes aligned at an ** 8-byte boundary. The page to be fetched is determined by the key. The ** mimimum key value is 1. After it has been retrieved using xFetch, the page ** is considered to be pinned. ** ** If the requested page is already in the page cache, then a pointer to ** the cached buffer should be returned with its contents intact. If the ** page is not already in the cache, then the expected behaviour of the ** cache is determined by the value of the createFlag parameter passed ** to xFetch, according to the following table: ** ** **
createFlagExpected Behaviour **
0NULL should be returned. No new cache entry is created. **
1If createFlag is set to 1, this indicates that ** SQLite is holding pinned pages that can be unpinned ** by writing their contents to the database file (a ** relatively expensive operation). In this situation the ** cache implementation has two choices: it can return NULL, ** in which case SQLite will attempt to unpin one or more ** pages before re-requesting the same page, or it can ** allocate a new page and return a pointer to it. If a new ** page is allocated, then the first sizeof(void*) bytes of ** it (at least) must be zeroed before it is returned. **
2If createFlag is set to 2, then SQLite is not holding any ** pinned pages associated with the specific cache passed ** as the first argument to xFetch() that can be unpinned. The ** cache implementation should attempt to allocate a new ** cache entry and return a pointer to it. Again, the first ** sizeof(void*) bytes of the page should be zeroed before ** it is returned. If the xFetch() method returns NULL when ** createFlag==2, SQLite assumes that a memory allocation ** failed and returns SQLITE_NOMEM to the user. **
** ** xUnpin() is called by SQLite with a pointer to a currently pinned page ** as its second argument. If the third parameter, discard, is non-zero, ** then the page should be evicted from the cache. In this case SQLite ** assumes that the next time the page is retrieved from the cache using ** the xFetch() method, it will be zeroed. If the discard parameter is ** zero, then the page is considered to be unpinned. The cache implementation ** may choose to reclaim (free or recycle) unpinned pages at any time. ** SQLite assumes that next time the page is retrieved from the cache ** it will either be zeroed, or contain the same data that it did when it ** was unpinned. ** ** The cache is not required to perform any reference counting. A single ** call to xUnpin() unpins the page regardless of the number of prior calls ** to xFetch(). ** ** The xRekey() method is used to change the key value associated with the ** page passed as the second argument from oldKey to newKey. If the cache ** previously contains an entry associated with newKey, it should be ** discarded. Any prior cache entry associated with newKey is guaranteed not ** to be pinned. ** ** When SQLite calls the xTruncate() method, the cache must discard all ** existing cache entries with page numbers (keys) greater than or equal ** to the value of the iLimit parameter passed to xTruncate(). If any ** of these pages are pinned, they are implicitly unpinned, meaning that ** they can be safely discarded. ** ** The xDestroy() method is used to delete a cache allocated by xCreate(). ** All resources associated with the specified cache should be freed. After ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*] ** handle invalid, and will not use it with any other sqlite3_pcache_methods ** functions. */ typedef struct sqlite3_pcache_methods sqlite3_pcache_methods; struct sqlite3_pcache_methods { void *pArg; int (*xInit)(void*); void (*xShutdown)(void*); sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable); void (*xCachesize)(sqlite3_pcache*, int nCachesize); int (*xPagecount)(sqlite3_pcache*); void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag); void (*xUnpin)(sqlite3_pcache*, void*, int discard); void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey); void (*xTruncate)(sqlite3_pcache*, unsigned iLimit); void (*xDestroy)(sqlite3_pcache*); }; /* ** CAPI3REF: Online Backup Object ** EXPERIMENTAL ** ** The sqlite3_backup object records state information about an ongoing ** online backup operation. The sqlite3_backup object is created by ** a call to [sqlite3_backup_init()] and is destroyed by a call to ** [sqlite3_backup_finish()]. ** ** See Also: [Using the SQLite Online Backup API] */ typedef struct sqlite3_backup sqlite3_backup; /* ** CAPI3REF: Online Backup API. ** EXPERIMENTAL ** ** This API is used to overwrite the contents of one database with that ** of another. It is useful either for creating backups of databases or ** for copying in-memory databases to or from persistent files. ** ** See Also: [Using the SQLite Online Backup API] ** ** Exclusive access is required to the destination database for the ** duration of the operation. However the source database is only ** read-locked while it is actually being read, it is not locked ** continuously for the entire operation. Thus, the backup may be ** performed on a live database without preventing other users from ** writing to the database for an extended period of time. ** ** To perform a backup operation: **
    **
  1. sqlite3_backup_init() is called once to initialize the ** backup, **
  2. sqlite3_backup_step() is called one or more times to transfer ** the data between the two databases, and finally **
  3. sqlite3_backup_finish() is called to release all resources ** associated with the backup operation. **
** There should be exactly one call to sqlite3_backup_finish() for each ** successful call to sqlite3_backup_init(). ** ** sqlite3_backup_init() ** ** The first two arguments passed to [sqlite3_backup_init()] are the database ** handle associated with the destination database and the database name ** used to attach the destination database to the handle. The database name ** is "main" for the main database, "temp" for the temporary database, or ** the name specified as part of the [ATTACH] statement if the destination is ** an attached database. The third and fourth arguments passed to ** sqlite3_backup_init() identify the [database connection] ** and database name used ** to access the source database. The values passed for the source and ** destination [database connection] parameters must not be the same. ** ** If an error occurs within sqlite3_backup_init(), then NULL is returned ** and an error code and error message written into the [database connection] ** passed as the first argument. They may be retrieved using the ** [sqlite3_errcode()], [sqlite3_errmsg()], and [sqlite3_errmsg16()] functions. ** Otherwise, if successful, a pointer to an [sqlite3_backup] object is ** returned. This pointer may be used with the sqlite3_backup_step() and ** sqlite3_backup_finish() functions to perform the specified backup ** operation. ** ** sqlite3_backup_step() ** ** Function [sqlite3_backup_step()] is used to copy up to nPage pages between ** the source and destination databases, where nPage is the value of the ** second parameter passed to sqlite3_backup_step(). If nPage is a negative ** value, all remaining source pages are copied. If the required pages are ** succesfully copied, but there are still more pages to copy before the ** backup is complete, it returns [SQLITE_OK]. If no error occured and there ** are no more pages to copy, then [SQLITE_DONE] is returned. If an error ** occurs, then an SQLite error code is returned. As well as [SQLITE_OK] and ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY], ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code. ** ** As well as the case where the destination database file was opened for ** read-only access, sqlite3_backup_step() may return [SQLITE_READONLY] if ** the destination is an in-memory database with a different page size ** from the source database. ** ** If sqlite3_backup_step() cannot obtain a required file-system lock, then ** the [sqlite3_busy_handler | busy-handler function] ** is invoked (if one is specified). If the ** busy-handler returns non-zero before the lock is available, then ** [SQLITE_BUSY] is returned to the caller. In this case the call to ** sqlite3_backup_step() can be retried later. If the source ** [database connection] ** is being used to write to the source database when sqlite3_backup_step() ** is called, then [SQLITE_LOCKED] is returned immediately. Again, in this ** case the call to sqlite3_backup_step() can be retried later on. If ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or ** [SQLITE_READONLY] is returned, then ** there is no point in retrying the call to sqlite3_backup_step(). These ** errors are considered fatal. At this point the application must accept ** that the backup operation has failed and pass the backup operation handle ** to the sqlite3_backup_finish() to release associated resources. ** ** Following the first call to sqlite3_backup_step(), an exclusive lock is ** obtained on the destination file. It is not released until either ** sqlite3_backup_finish() is called or the backup operation is complete ** and sqlite3_backup_step() returns [SQLITE_DONE]. Additionally, each time ** a call to sqlite3_backup_step() is made a [shared lock] is obtained on ** the source database file. This lock is released before the ** sqlite3_backup_step() call returns. Because the source database is not ** locked between calls to sqlite3_backup_step(), it may be modified mid-way ** through the backup procedure. If the source database is modified by an ** external process or via a database connection other than the one being ** used by the backup operation, then the backup will be transparently ** restarted by the next call to sqlite3_backup_step(). If the source ** database is modified by the using the same database connection as is used ** by the backup operation, then the backup database is transparently ** updated at the same time. ** ** sqlite3_backup_finish() ** ** Once sqlite3_backup_step() has returned [SQLITE_DONE], or when the ** application wishes to abandon the backup operation, the [sqlite3_backup] ** object should be passed to sqlite3_backup_finish(). This releases all ** resources associated with the backup operation. If sqlite3_backup_step() ** has not yet returned [SQLITE_DONE], then any active write-transaction on the ** destination database is rolled back. The [sqlite3_backup] object is invalid ** and may not be used following a call to sqlite3_backup_finish(). ** ** The value returned by sqlite3_backup_finish is [SQLITE_OK] if no error ** occurred, regardless or whether or not sqlite3_backup_step() was called ** a sufficient number of times to complete the backup operation. Or, if ** an out-of-memory condition or IO error occured during a call to ** sqlite3_backup_step() then [SQLITE_NOMEM] or an ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] error code ** is returned. In this case the error code and an error message are ** written to the destination [database connection]. ** ** A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step() is ** not a permanent error and does not affect the return value of ** sqlite3_backup_finish(). ** ** sqlite3_backup_remaining(), sqlite3_backup_pagecount() ** ** Each call to sqlite3_backup_step() sets two values stored internally ** by an [sqlite3_backup] object. The number of pages still to be backed ** up, which may be queried by sqlite3_backup_remaining(), and the total ** number of pages in the source database file, which may be queried by ** sqlite3_backup_pagecount(). ** ** The values returned by these functions are only updated by ** sqlite3_backup_step(). If the source database is modified during a backup ** operation, then the values are not updated to account for any extra ** pages that need to be updated or the size of the source database file ** changing. ** ** Concurrent Usage of Database Handles ** ** The source [database connection] may be used by the application for other ** purposes while a backup operation is underway or being initialized. ** If SQLite is compiled and configured to support threadsafe database ** connections, then the source database connection may be used concurrently ** from within other threads. ** ** However, the application must guarantee that the destination database ** connection handle is not passed to any other API (by any thread) after ** sqlite3_backup_init() is called and before the corresponding call to ** sqlite3_backup_finish(). Unfortunately SQLite does not currently check ** for this, if the application does use the destination [database connection] ** for some other purpose during a backup operation, things may appear to ** work correctly but in fact be subtly malfunctioning. Use of the ** destination database connection while a backup is in progress might ** also cause a mutex deadlock. ** ** Furthermore, if running in [shared cache mode], the application must ** guarantee that the shared cache used by the destination database ** is not accessed while the backup is running. In practice this means ** that the application must guarantee that the file-system file being ** backed up to is not accessed by any connection within the process, ** not just the specific connection that was passed to sqlite3_backup_init(). ** ** The [sqlite3_backup] object itself is partially threadsafe. Multiple ** threads may safely make multiple concurrent calls to sqlite3_backup_step(). ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount() ** APIs are not strictly speaking threadsafe. If they are invoked at the ** same time as another thread is invoking sqlite3_backup_step() it is ** possible that they return invalid values. */ sqlite3_backup *sqlite3_backup_init( sqlite3 *pDest, /* Destination database handle */ const char *zDestName, /* Destination database name */ sqlite3 *pSource, /* Source database handle */ const char *zSourceName /* Source database name */ ); int sqlite3_backup_step(sqlite3_backup *p, int nPage); int sqlite3_backup_finish(sqlite3_backup *p); int sqlite3_backup_remaining(sqlite3_backup *p); int sqlite3_backup_pagecount(sqlite3_backup *p); /* ** CAPI3REF: Unlock Notification ** EXPERIMENTAL ** ** When running in shared-cache mode, a database operation may fail with ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or ** individual tables within the shared-cache cannot be obtained. See ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. ** This API may be used to register a callback that SQLite will invoke ** when the connection currently holding the required lock relinquishes it. ** This API is only available if the library was compiled with the ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined. ** ** See Also: [Using the SQLite Unlock Notification Feature]. ** ** Shared-cache locks are released when a database connection concludes ** its current transaction, either by committing it or rolling it back. ** ** When a connection (known as the blocked connection) fails to obtain a ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the ** identity of the database connection (the blocking connection) that ** has locked the required resource is stored internally. After an ** application receives an SQLITE_LOCKED error, it may call the ** sqlite3_unlock_notify() method with the blocked connection handle as ** the first argument to register for a callback that will be invoked ** when the blocking connections current transaction is concluded. The ** callback is invoked from within the [sqlite3_step] or [sqlite3_close] ** call that concludes the blocking connections transaction. ** ** If sqlite3_unlock_notify() is called in a multi-threaded application, ** there is a chance that the blocking connection will have already ** concluded its transaction by the time sqlite3_unlock_notify() is invoked. ** If this happens, then the specified callback is invoked immediately, ** from within the call to sqlite3_unlock_notify(). ** ** If the blocked connection is attempting to obtain a write-lock on a ** shared-cache table, and more than one other connection currently holds ** a read-lock on the same table, then SQLite arbitrarily selects one of ** the other connections to use as the blocking connection. ** ** There may be at most one unlock-notify callback registered by a ** blocked connection. If sqlite3_unlock_notify() is called when the ** blocked connection already has a registered unlock-notify callback, ** then the new callback replaces the old. If sqlite3_unlock_notify() is ** called with a NULL pointer as its second argument, then any existing ** unlock-notify callback is cancelled. The blocked connections ** unlock-notify callback may also be canceled by closing the blocked ** connection using [sqlite3_close()]. ** ** The unlock-notify callback is not reentrant. If an application invokes ** any sqlite3_xxx API functions from within an unlock-notify callback, a ** crash or deadlock may be the result. ** ** Unless deadlock is detected (see below), sqlite3_unlock_notify() always ** returns SQLITE_OK. ** ** Callback Invocation Details ** ** When an unlock-notify callback is registered, the application provides a ** single void* pointer that is passed to the callback when it is invoked. ** However, the signature of the callback function allows SQLite to pass ** it an array of void* context pointers. The first argument passed to ** an unlock-notify callback is a pointer to an array of void* pointers, ** and the second is the number of entries in the array. ** ** When a blocking connections transaction is concluded, there may be ** more than one blocked connection that has registered for an unlock-notify ** callback. If two or more such blocked connections have specified the ** same callback function, then instead of invoking the callback function ** multiple times, it is invoked once with the set of void* context pointers ** specified by the blocked connections bundled together into an array. ** This gives the application an opportunity to prioritize any actions ** related to the set of unblocked database connections. ** ** Deadlock Detection ** ** Assuming that after registering for an unlock-notify callback a ** database waits for the callback to be issued before taking any further ** action (a reasonable assumption), then using this API may cause the ** application to deadlock. For example, if connection X is waiting for ** connection Y's transaction to be concluded, and similarly connection ** Y is waiting on connection X's transaction, then neither connection ** will proceed and the system may remain deadlocked indefinitely. ** ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock ** detection. If a given call to sqlite3_unlock_notify() would put the ** system in a deadlocked state, then SQLITE_LOCKED is returned and no ** unlock-notify callback is registered. The system is said to be in ** a deadlocked state if connection A has registered for an unlock-notify ** callback on the conclusion of connection B's transaction, and connection ** B has itself registered for an unlock-notify callback when connection ** A's transaction is concluded. Indirect deadlock is also detected, so ** the system is also considered to be deadlocked if connection B has ** registered for an unlock-notify callback on the conclusion of connection ** C's transaction, where connection C is waiting on connection A. Any ** number of levels of indirection are allowed. ** ** The "DROP TABLE" Exception ** ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost ** always appropriate to call sqlite3_unlock_notify(). There is however, ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement, ** SQLite checks if there are any currently executing SELECT statements ** that belong to the same connection. If there are, SQLITE_LOCKED is ** returned. In this case there is no "blocking connection", so invoking ** sqlite3_unlock_notify() results in the unlock-notify callback being ** invoked immediately. If the application then re-attempts the "DROP TABLE" ** or "DROP INDEX" query, an infinite loop might be the result. ** ** One way around this problem is to check the extended error code returned ** by an sqlite3_step() call. If there is a blocking connection, then the ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in ** the special "DROP TABLE/INDEX" case, the extended error code is just ** SQLITE_LOCKED. */ int sqlite3_unlock_notify( sqlite3 *pBlocked, /* Waiting connection */ void (*xNotify)(void **apArg, int nArg), /* Callback function to invoke */ void *pNotifyArg /* Argument to pass to xNotify */ ); /* ** Undo the hack that converts floating point types to integer for ** builds on processors without floating point support. */ #ifdef SQLITE_OMIT_FLOATING_POINT # undef double #endif #ifdef __cplusplus } /* End of the 'extern "C"' block */ #endif #endif