Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!hp-sdd!hp-pcd!hplsla!davidr
From: davidr@hplsla.HP.COM (David M. Reed)
Newsgroups: comp.lang.pascal
Subject: Re: disable ^C in Turbo Pascal
Message-ID: <6490005@hplsla.HP.COM>
Date: 17 Feb 90 01:43:29 GMT
References: <116500002@uxa.cso.uiuc.edu>
Organization: HP Lake Stevens, WA
Lines: 35

In my Turbo Pascal 3.x programs I used, very successfully, {$C-}, after
thoroughly debugging a program (or *I* would not be able to interrupt
something running wild).  I particularly did this for the benefit of 
using the DOS type-ahead buffering, plus a small screen speed improvement.
And, of course, in a login/password program I created to use on some
shared systems.  In Turbo Pascal 5.x you must set Borland's global variable
CheckBreak := FALSE (from the CRT unit).

Last June I found a suggestion posted to comp.sys.ibm.pc which has been
helpful for the shared systems I put my login program on.  It is simple
to use in thwarting users from aborting the boot process until it is
finished.  It only works with MS-DOS 3.3 or later.

In CONFIG.SYS make certain you specify

    BREAK = OFF
    DEVICE = ANSI.SYS

Then my first two statements in AUTOEXEC.BAT are

    @ECHO OFF
    ECHO ^[[3;67p

and my last statements are

    ECHO ^[[3;3p
    MENU

The need for MS-DOS 3.3 (or later) is so that the first statment is not
echoed to the screen (which is when DOS looks for a ^C code).  The second
echo is the ANSI escape code sequence for key re-mapping, specifying that
ASCII code 3 (the ^C character) should be remapped as a simple C character,
and the last statement restores the original definition.  Now the only
way some can circumvent my defined boot-up process on those systems (to
bypass the login/password program) is to boot from a floppy.