Directorty Opus 5 - Magellan 2/Opus 5 - Magellan 2.iso/DOpus_SDK_5.5/docs/bufferedio.doc

Text File | 1996-09-05 | 5KB | 216 lines

TABLE OF CONTENTS

dopus5.library/CloseBuf
dopus5.library/ExamineBuf
dopus5.library/FHFromBuf
dopus5.library/FlushBuf
dopus5.library/OpenBuf
dopus5.library/ReadBuf
dopus5.library/SeekBuf
dopus5.library/WriteBuf
dopus5.library/CloseBuf                               dopus5.library/CloseBuf

    NAME
        CloseBuf - close a buffered file

    SYNOPSIS
        CloseBuf(file)
                  A0

        void CloseBuf(APTR);

    FUNCTION
        Closes a file opened with OpenBuf().

    INPUTS
        file - file to close

    RESULT
        Any write data in the buffer is written to disk and the
        file is closed.

    SEE ALSO
        OpenBuf()
dopus5.library/ExamineBuf                           dopus5.library/ExamineBuf

    NAME
        ExamineBuf - Examine an open file

    SYNOPSIS
        ExamineBuf(file, fib)
                    A0    A1

        long ExamineBuf(APTR, struct FileInfoBlock *);

    FUNCTION
        This function calls ExamineFH() on the underlying DOS file handle.

    INPUTS
        file - file to examine
        fib - FileInfoBlock structure, must be longword aligned

    RESULT
        Returns DOSTRUE if successful. The FileInfoBlock will contain
        information about the open file.

    BUGS
        If the file is open for writing, the file size reported by this
        function may not be accurate.

    SEE ALSO
        OpenBuf(), dos.library/ExamineFH()

dopus5.library/FHFromBuf                             dopus5.library/FHFromBuf

    NAME
        FHFromBuf - get DOS file handle

    SYNOPSIS
        FHFromBuf(file)
                   A0

        BPTR FHFromBuf(APTR);

    FUNCTION
        This function returns the underlying DOS file handle for a
        buffered IO handle.

    INPUTS
        file - buffered IO file handle

    RESULT
        Returns the file handle.

    SEE ALSO
        OpenBuf()
dopus5.library/FlushBuf                               dopus5.library/FlushBuf

    NAME
        FlushBuf - flush file buffer

    SYNOPSIS
        FlushBuf(file)
                  A0

        void FlushBuf(APTR);

    FUNCTION
        This function flushes the buffer of a buffered IO file. If there
        is any write data in the buffer, it is written to disk.

    INPUTS
        file - file handle to flush

    RESULT
        The buffer is flushed.

    NOTES
        In practice, you never need to call this function.

    SEE ALSO
        OpenBuf(), WriteBuf(), ReadBuf()
dopus5.library/OpenBuf                                 dopus5.library/OpenBuf

    NAME
        OpenBuf - open a file for buffered I/O

    SYNOPSIS
        OpenBuf(name, mode, bufsize)
                 A0    D0     D1

        APTR OpenBuf(char *, long, long);

    FUNCTION
        This function opens a file for use with the buffered I/O routines.

    INPUTS
        name - name of the file to open
        mode - mode to use
        bufsize - size of the buffer to use

    RESULT
        Returns a buffered file handle if successful, or NULL. This is
        not a standard DOS file handle, and can only be used with the
        other buffered IO functions.

    SEE ALSO
        CloseBuf(), dos.library/Open()
dopus5.library/ReadBuf                                 dopus5.library/ReadBuf

    NAME
        ReadBuf - read data from a buffered file

    SYNOPSIS
        ReadBuf(file, buffer, size)
                 A0     A1     D0

        long ReadBuf(APTR, char *, long);

    FUNCTION
        This function reads data from a buffered IO file.

    INPUTS
        file - buffered IO file handle
        buffer - buffer to place data in
        size - size to read

    RESULT
        This function returns the size of the data actually read,
        or -1 if an error occurred.

    SEE ALSO
        OpenBuf(), dos.library/Read()

dopus5.library/SeekBuf                                 dopus5.library/SeekBuf

    NAME
        SeekBuf - seek within a buffered IO file

    SYNOPSIS
        SeekBuf(file, offset, mode)
                 A0     D0     D1

        long SeekBuf(APTR, long, long);

    FUNCTION
        This function sets the read/write position for a buffered IO file.
        If the seek takes the position outside of the current buffer, the
        buffer will be flushed and re-read automatically.

    INPUTS
        file - file to seek within
        offset - offset to seek
        mode - type of seet (OFFSET_BEGINNING, OFFSET_CURRENT, OFFSET_END)

    RESULT
        Returns the previous file position.

    SEE ALSO
        OpenBuf(), dos.library/Seek()

dopus5.library/WriteBuf                               dopus5.library/WriteBuf

    NAME
        WriteBuf - write data to a buffered IO file

    SYNOPSIS
        WriteBuf(file, data, size)
                  A0    A1    D0

        long WriteBuf(APTR, char *, long);

    FUNCTION
        Writes data to a file opened for buffered IO.

    INPUTS
        file - file handle
        data - data to write
        size - size to write (-1 works for a null-terminated string)

    RESULT
        Returns the number of bytes written, or -1 for an error.

    SEE ALSO
        OpenBuf(), dos.library/Write()