Int 21H, AH=33H, AL=01H

2 and higher

set state of extended Ctrl-C/Ctrl-Break checking

      AH = 33h
      AL = 01h
      DL = new state
                  00h off, check only on character I/O functions
                  01h on, check on all DOS functions

(Novell DOS 7) DL = old state of extended Break checks

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

AX=3302h

Text based on Ralf Brown Interrupt List Release 61