Int 21 Fn 33  - DOS 2+ - Extended Break Checking                           [D]

   AH = 33h
   AL = subfunction
       00h get current extended break state

       Return: DL = current state, 00h = off, 01h = on
       01h set state of extended  Break checking
       DL = 00h off, check only on character I/O functions
            01h on, check on all DOS functions

Note:  under DOS 3.1+ and DR-DOS, this function does not use any of the
     DOS-internal stacks and may thus be called at any time

See Also: AX=3302h