Seek Type

     open/4 option:  seek(SeekType)
     QP_stream:      unsigned char seek_type
     

This field specifies which type of seeking can be performed on the stream. The possible values for seek_type are:

QP_SEEK_ERROR

specified as seek(error) in open/4. It is an error to perform any type of seeking operation on the stream. Any call to seek/4, stream_position/3, QP_seek() or QP_setpos() is an error.

QP_SEEK_PREVIOUS

specified as seek(previous) in open/4. The stream only seeks back to a previous read or written position. The previous position must be saved through QP_getpos() or stream_position/[2,3]. The seeking can only be performed through stream_position/3 or QP_setpos().

QP_SEEK_BYTE

specified as seek(byte) in open/4. The stream can seek to any arbitrary byte offset in the file or to any previously saved position. In addition to the seeking method described in QP_SEEK_PREVIOUS, the stream can also seek through seek/4 or QP_seek().

QP_SEEK_RECORD

specified as seek(record) in open/4. The stream can seek to an arbitrary record number in the file or to any previously saved position.

The seek function must be supplied for a user-defined stream with seek_type set to any value other than QP_SEEK_ERROR.