Q40359: Turning the Scroll Lock On

Article: Q40359
Product(s): See article
Version(s): 5.00 5.10 | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | s_quickc | mspl13_c
Last Modified: 16-JAN-1989

The following code illustrates how to turn the Scroll Lock on in
your program. Note: This code is only for use under DOS. Running
it under OS/2 will cause a protection violation. Use the OS/2
FAPI function KbdSetStatus to set the status of shift flags when
writing programs which will run under OS/2 or be bound to run under
both DOS and OS/2.

#include <stdio.h>
main()
{
   /* Get the address of the keyboard status byte */
   char far *kbdstat=0x00000417L;

   char scrollmask=0x10;

   /* OR *kbdstat with scrollmask to set bit 4 in the
      keyboard status byte to 1 */

   *kbdstat= *kbdstat | scrollmask;
}

Additional information on keyboard status can be found in the Peter
Norton "Programmer's Guide to the IBM PC and PS/2." The above information
also applies to QuickC.

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