Click above to get retro games delivered to your door ever month!

 bioskey()               Keyboard Interface

 #include   <bios.h>

 int        bioskey(cmd);
 int        cmd;                         Operation to perform

    bioskey() uses BIOS interrupt 0x16 to perform one of the following
    keyboard operations specified by 'cmd':

           0    Return the next keystroke. If the lower 8 bits are non-
                zero, an ASCII character is returned.  If the lower 8
                bits are 0, the upper 8 bits represent an extended
                keyboard code.

           1    Check if a keystroke is available and return its value.
                If 0 is returned, no keystroke is waiting.  The keystroke
                itself is kept until the next call to bioskey() with
                'cmd' specified as 0.

           2    Request the current shift key status.  The value is
                determined by ORing the following:

                0x80     'Insert' toggled
                0x40     'Caps Lock' toggled
                0x20     'Num Lock' toggled
                0x10     'Scroll Lock' toggled
                0x08     'Alt' down
                0x04     'Ctrl' down
                0x02     'Left Shift' down
                0x01     'Right Shift' down

       Returns:     A value based on the value of 'cmd', as described
                    above.

   Portability:     IBM PC and compatibles only.

   -------------------------------- Example ---------------------------------

    The following statements continually write out the value of the last
    key pressed until a non-printing character or alt, ctrl or shift is
    pressed.

           #include <stdio.h>              /* for printf and putch */
           #include <bios.h>               /* for bioskey */
           #include <ctype.h>              /* for isprint */

           main()
           {
               int key, modifier_key = 0;

               printf("Press a key\n");
               key = bioskey(0);                   /* read first key */
               while ((key & 0xFF) != 0 && isprint(key & 0xFF)
                       && !modifier_key) {
                   putch(key);
                   modifier_key = bioskey(2) & 0x0F;/* get ctl, alt, shift */
                   if (bioskey(1))                 /* if key is waiting */
                       key = bioskey(0);       /* then read it */
               }
           }