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ThreadFile Class Reference This class defines a database I/O file service that can be shared by multiple threads. This class defines a database I/O file service that can be shared by multiple threads. More... #include <file.h> Inheritance diagram for ThreadFile: List of all members. Public Methods   ThreadFile (const char *path)   Open or create a new database file. More...   ~ThreadFile ()   Close and finish a database file. fileerror_t  Restart (void)   Restart an existing database; close and re-open. More... fileerror_t  Fetch (caddr_t address = NULL, size_t length = 0, off_t position = - 1)   Fetch a portion of the file into physical memory. More... fileerror_t  Update (caddr_t address = NULL, size_t length = 0, off_t position = -1)   Update a portion of a file from physical memory. More... fileerror_t  Append (caddr_t address = NULL, size_t length = 0)   Add new data to the end of the file. More... off_t  getPosition (void)   Fetch the current file position marker for this thread. More... bool  operator++ (void) bool  operator-- (void) Detailed Description This class defines a database I/O file service that can be shared by multiple threads. This class defines a database I/O file service that can be shared by multiple threads. All threads access a global copy of the database object, and mutex locks can be used to preserve transaction integrety. pread/pwrite calls can be used for optimized I/O when supported. ThreadFile is meant for use by a threaded database server where multiple threads may each perform semi-independent operations on a given database table stored on disk. A special "fcb" structure is used to hold file "state", and pread/pwrite is used whenever possible for optimized I/O. On systems that do not offer pwread/pwrite, a Mutex lock is used to protect concurrent lseek and read/write operations. ThreadFile managed databases are assumed to be used only by the local server and through a single file descriptor. Author(s): David Sugar <dyfet@ostel.com> Constructor & Destructor Documentation ThreadFile::ThreadFile ( const char * path )   Open or create a new database file. You should also use Initial. Parameters: pathname   of database to open. ThreadFile::~ThreadFile ( )   Close and finish a database file. Member Function Documentation fileerror_t ThreadFile::Append ( caddr_t address = NULL, size_t length = 0 )   Add new data to the end of the file. Parameters: address   to use, or NULL if same as last I/O. length   to use, or 0 if same as last I/O. fileerror_t ThreadFile::Fetch ( caddr_t address = NULL, size_t length = 0, off_t position = - 1 )   Fetch a portion of the file into physical memory. This can use state information to fetch the current record multiple times. Returns: FILE_SUCCESS on success. Parameters: address   to use, or NULL if same as last I/O. length   to use, or 0 if same as last I/O. file   position to use -1 if same as last I/O. fileerror_t ThreadFile::Restart ( void ) [inline, virtual]   Restart an existing database; close and re-open. Returns: FILE_SUCCESS if successful. Reimplemented from RandomFile. fileerror_t ThreadFile::Update ( caddr_t address = NULL, size_t length = 0, off_t position = -1 )   Update a portion of a file from physical memory. This can use state information to commit the last read record. Returns: FILE_SUCCESS on success. Parameters: address   to use, or NULL if same as last I/O. length   to use, or 0 if same as last I/O. file   position to use or -1 if same as last I/O. off_t ThreadFile::getPosition ( void )   Fetch the current file position marker for this thread. Returns: file position offset. bool ThreadFile::operator++ ( void ) bool ThreadFile::operator-- ( void ) The documentation for this class was generated from the following file: file.h