[Back to PRINTING SWAG index] [Back to Main SWAG index] [Original]

    {
    >>    I'm using TP6 and plan to use to the PRINTER.TPU unit the
    >>    write to the printer.  How do you detect whether the printer
    >>    is on or not without ending up a dos error and the program
    >>    halting.

       You need to check the status of the printer port.  Something like
    this:
    }

    function TESTONLINE : Byte;           { Tests for Printer On Line }
    var REGS : Registers;
    begin
      with REGS do
        begin
          AH := 2; DX := 0;
          Intr($17, Dos.Registers(REGS));
          TESTONLINE := AH
        end
    end;  { TESTONLINE }

      if TESTONLINE = 144 then okay_to_print
      else                     printer_not_ready

[Back to PRINTING SWAG index] [Back to Main SWAG index] [Original]