Int 21 Fn E8  - Doubledos - Set/reset Keyboard Control Flags               [T]

   AH = E8h
   AL = 00h set flags for this program
      = 01h set flags for other program
   DX = keyboard control flags (see below)

Return: DX = previous flags

Notes: disabling Ctrl-PrtSc will allow the program to intercept the keystroke;
     disabling any of the other keystrokes disables them completely
   identical to AH=F8h

See Also: AH=E1h"DoubleDOS",AH=E2h"DoubleDOS",AH=E3h"DoubleDOS"

See Also: AH=F8h"DoubleDOS"

Bitfields for keyboard control flags:
 bit 0 menu
 bit 1 exchange
 bit 2 entire keyboard enable/disable
 bit 3 Ctrl-C
 bit 4 Ctrl-PrtSc
 bit 5 Alt/Erase
 bit 6 Ctrl-Break
 bit 7 Ctrl-NumLock
 bit 8 shift-PrtSc
 bit 9-13 undefined
 bit 14 cancel key (clear keyboard buffer)
 bit 15 suspend key

Note:  setting a bit enables the corresponding key or operatin, clearing a
     bit disables it