sqlite3.h

sqlite - amalgamation source

  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} <S30800>
**
** 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} <S20130>
**
** 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} <S20100>
**
** 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:
**
** <ul>
** <li>  [SQLITE_OPEN_MAIN_DB]
** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
** <li>  [SQLITE_OPEN_TEMP_DB]
** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
** <li>  [SQLITE_OPEN_TRANSIENT_DB]
** <li>  [SQLITE_OPEN_SUBJOURNAL]
** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
** </ul>
**
** 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:
**
** <ul>
** <li> [SQLITE_OPEN_DELETEONCLOSE]
** <li> [SQLITE_OPEN_EXCLUSIVE]
** </ul>
**
** 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} <H11140>
**
** 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} <S20000><S30100>
**
** 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} <S20000><S30200>
** 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