PRODUCT  :  Borland C++                            NUMBER  :  711
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 26, 1993                         PAGE  :  1/2

    TITLE  :  Disabling CTRL-BREAK and CTRL-C




  /**********************************************************

  The following code shows how to disable CTRL-BREAK and
  CTRL-C.

  ************************************************************/

  #include <conio.h>
  #include <dos.h>
  #include <stdlib.h>

  char far *modifiers = MK_FP(0,0x417); /* address of modifier
  flags     */
  void interrupt (*oldint9) (void);     /* storage for old INT 9
  handler */

  void interrupt myint9(void)
  {
  /* ((*modifiers)&4)==4 indicates the CTRL key is being pressed

         inportb(0x60)==46 indicates the C key is being pressed
         inportb(0x60)==70 indicates the SCROLL LOCK/BREAK key "

         The emit code is required to clean the keypress up from

         the BIOS.
  */

      if( (((*modifiers)&4)==4) &&
          ((inportb(0x60)==46) || (inportb(0x60)==70)) )
          __emit__(0xe4,0x61,   /* asm    IN   AL,61 */
                   0x8a,0xe0,   /* asm    MOV  AH,AL */
                   0x0c,0x80,   /* asm    OR   AL,80 */
                   0xe6,0x61,   /* asm    OUT  61,AL */
                   0x86,0xe0,   /* asm    XCHG      AL,AH */
                   0xe6,0x61,   /* asm    OUT  61,AL */
                   0xb0,0x20,   /* asm    MOV  AL,20 */
                   0xe6,0x20);  /* asm    OUT  20,AL */
      else
  /* If the key is not CTRL-C or CTRL-BREAK, call the old INT 9
     handler */
     oldint9();
  }













  PRODUCT  :  Borland C++                            NUMBER  :  711
  VERSION  :  2.0
       OS  :  DOS
     DATE  :  October 26, 1993                         PAGE  :  2/2

    TITLE  :  Disabling CTRL-BREAK and CTRL-C




  void exitfunc(void)
  {
  /* Restore the old INT 9 handler */
      setvect(9,oldint9);
  }

  main()
  {
     int i;

     oldint9=getvect(9);  /* store old interrupt vector */
     setvect(9,myint9);   /* set up new interrupt handler */
     atexit(exitfunc);    /* set up exit handler to restore INT 9*/

      /* ... */    /* code that will not CTRL-BREAK or CTRL-C */

      return 0;
  }

  DISCLAIMER: You have the right to use this technical information
  subject to the terms of the No-Nonsense License Statement that
  you received with the Borland product to which this information
  pertains.