NAME
        CD_PLAYLSN -- Play a selected portion of CD audio (LSN form).

   IO REQUEST
       io_Device       preset by the call to opendevice()
       io_Unit         preset by the call to opendevice()
       io_Command      CD_PLAYLSN
       io_Data         NULL
       io_Length       length of play
       io_Offset       starting position

   RESULTS
       io_Error        0 for success, or an error code as defined in
                       <devices/cd.h>

   FUNCTION
       This command causes the drive to start playing CD audio from the
       specified position until the specified length has passed.

       io_Offset specifies the starting position.  io_Length contains
       the amount of time to play.  All data is specified in LSN format.

       A doio() will not return until the requested number of sectors
       have been played.  A sendio() will return as soon as the play
       has been started.  At this time other commands can be sent (like
       CD_PAUSE).  To stop a play before the specified length has been
       reached, use abortio().

   EXAMPLE
       /* Play two minutes, ten seconds of audio starting at 20 minutes, */
       /* 58 seconds, and 10 frames.                                     */

       ior->io_Command = CD_PLAYLSN;   /* Play CD audio           */
       ior->io_Offset  = 94360;        /* 20*(60*75) + 58*75 + 10 */
       ior->io_Length  = 9750;         /* 02*(60*75) + 10*75 + 00 */
       doio (ior);

   NOTES

   BUGS

   SEE ALSO
       cd_playtrack, cd_pause, cd_search, cd_attenuate