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)