[Contents] [Index] [Help] [Retrace] [Browse <] [Browse >]

You can control the parallel parameters shown in the following table. The
parameter name within the parallel IOExtPar data structure is shown below.
All of the fields described in this section are filled with defaults when
you call OpenDevice().  Thus, you need not worry about any parameter that
you do not need to change.  The parameters are defined in the include file
devices/parallel.h.

                   PARALLEL PARAMETERS (IOExtPar)
   IOExtPar
   Field Name      Parallel Device Parameter It Controls
   ----------      -------------------------------------
   io_PExtFlags    Reserved for future use.

   io_PTermArray   A byte-array of eight termination characters, must
                   be in descending order.  If EOFMODE is set in the
                   parallel flags, this array specifies eight possible
                   choices of characters to use as an end-of-file mark.
                   See the section above titled  "Ending A Read Or Write
                   with Termination Characters" and the PDCMD_SETPARAMS
                   summary page in the Autodocs.

   io_Status       Contains status information.  It is filled in by the
                   PDCMD_QUERY command.

   io_ParFlags     See "Parallel Flags" below.

You set the parallel parameters by passing an IOExtPar to the device with
PDCMD_SETPARAMS set in io_Command and with the flags and parameters set to
the values you want.

   ParallelIO->io_ParFlags     &= ~PARF_EOFMODE;   /* Set EOF mode */
   ParallelIO->IOPar.io_Command = PDCMD_SETPARAMS; /* Set params command */
   if (DoIO(ParallelIO);
       printf("Error setting parameters!\n");

The above code fragment modifies one bit in io_ParFlags, then sends the
command.

   Proper Time for Parameter Changes.
   ----------------------------------
   A parameter change should not be performed while an I/O request is
   actually being processed, because it might invalidate already active
   request handling.  Therefore you should use PDCMD_SETPARAMS only when
   you have no parallel I/O requests pending.

 Parallel Flags (Bit Definitions For Io_parflags)