PRODUCT  :  Borland C++                           NUMBER  :  1546
  VERSION  :  3.x
       OS  :  DOS
     DATE  :  October 25, 1993                         PAGE  :  1/2

    TITLE  :  How to check printer status




  /*
  * Program to demonstrate checking the parallel ports to see if
  * it is ready to print.  Some other info about the printer is
  * shown in the process.   If you check the port in this way,
  * you won't have to wait for a timeout error when you try to
  * write to the printer and fail.
  */

  #include <dos.h>
  #include <stdio.h>
  #include <bios.h>

  /* these are various single bits in the status byte returned
  * from the printer.
  */
  #define TIMEOUT 0x01
  // bits 1 and 2 are not used.
  #define PRERROR 0x08
  #define ONLINE  0x10
  #define NOPAPER 0x20
  #define ACKNOWL 0x40
  #define NOTBUSY 0x80

  void ShowStatus( unsigned printerID );

  main()
  {
      int i;
      for (i=0; i<3; ++i)
      ShowStatus(i);
      return 0;
  }

  void ShowStatus(unsigned printerID)
  {
      /* pointer to BIOS data area which has port addresses of
      *   printers
      */
      static unsigned far *biosdata =
      (unsigned far *) MK_FP(0x0040,0x0008);
      unsigned char status;

      printf("\nPrinter Port LPT%d:\n",printerID+1);













  PRODUCT  :  Borland C++                           NUMBER  :  1546
  VERSION  :  3.x
       OS  :  DOS
     DATE  :  October 25, 1993                         PAGE  :  2/2

    TITLE  :  How to check printer status




      /* the port address is set to 0 if the printer is not
      *   installed
      */
      if (*(biosdata+printerID)==0)
      {
          printf("Not Installed\n");
          return;
      }

      /* we'll use interrupt 0x17, function 1 (Initialize Printer)
      * to check the status of the printer.
      */
      status = biosprint(1,0,printerID);

      /* display some info about the printer (optional)
      */
      if (status & TIMEOUT) printf("Timeout\t");
      else printf("No Timeout\t");
      if (status & PRERROR) printf("Error\t");
      else printf("No Error\t");
      if (status & ONLINE)  printf("Online\t");
      else printf("Not Online\t");
      if (status & NOPAPER) printf("\nOut of Paper\t");
      else printf("\nHas Paper\t");
      if (status & ACKNOWL) printf("No Acknowledge\t");
      else printf("Acknowledge\t");
      if (status & NOTBUSY) printf("Not Busy\n");
      else printf("Busy\n");

      /* ONLINE and NOTBUSY must both be ON for the printer to be
      * OK to print to.
      */
      if ((status & (ONLINE|NOTBUSY)) == (ONLINE|NOTBUSY))
      printf("READY to Print\n");
      else printf("NOT READY to Print\n");
  }


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