Q30370: Reading F11 and F12 Keys on Extended Keyboard

Article: Q30370
Product(s): See article
Version(s): 5.00 5.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | | mspl13_c
Last Modified: 11-AUG-1989

The following program will allow you to read the F11 and F12 keys
on an extended keyboard. The key to this process is to call
_bios_keybrd() with the service argument 0x10. This will allow an
extended keyboard read. This program will sit in an infinite loop
until F11 or F12 is pressed. Note that the C run-time library
functions getch() or getche() will not be able to read in the extended
function keys even after the change above has been made.

#include <bios.h>
#include <stdio.h>
#define _EXTKEYREAD 0x10
#define MASK 0xFF00
#define ZMASK 0x00FF
main()
{
  unsigned value, nextval;
  while(1)
  {
  value = _bios_keybrd(_EXTKEYREAD);
  nextval = value;
  if ((value & ZMASK) == 0)         /* check low order byte for zero*/
                                    /* if zero, then we have extended key*/
    {

       if((nextval & MASK) == 0x8500)   /* buffer code = 8500h for F11 */
       printf("F11 key pushed\n");

       if((nextval & MASK) == 0x8600)   /* buffer code = 8600 for F12 */
       printf("F12 key pushed\n");
    }
  else
    printf("not an extended key\n");

  }
}

THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY.

Copyright Microsoft Corporation 1986-2002.