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From: fs-info@sbsvax.cs.uni-sb.de (c/o Peter Gaal)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Need help:Ctrl-C and Ctrl-Break
Summary: Not so complicated...
Message-ID: <5717@sbsvax.cs.uni-sb.de>
Date: 31 Jul 90 10:57:18 GMT
References: <1990Jul30.182430.7493@uokmax.uucp> <9627@tekigm2.MEN.TEK.COM> <1990Jul31.023745.1116@water.waterloo.edu>
Organization: Universitaet des Saarlandes, Saarbruecken, W-Germany
Lines: 43

In article <1990Jul31.023745.1116@water.waterloo.edu>, nmouawad@water.waterloo.edu (Naji Mouawad) writes:
> In article <9627@tekigm2.MEN.TEK.COM> dennisw@tekigm2.MEN.TEK.COM (Dennis G
> Ward) writes:
> 
> >input.  What's the trick(s)?
> >-- 
> >Dennis Ward    dennisw@tekigm2.MEN.TEK.COM    C1-820    (206)253-5428
> 
> The best method I know of, is to trap interrupt 09h. Write a little routine
> that does the following:
> ["little" deleted]

Hmm, with your suggestion, you have to do scancode processing yourself,
but why shouldn't MSDOS do the work for you ?

The following should work:
  Choose a global flag variable, say c_break
  Replace INT09h with the following (meta)code:
    call original int09h
    look if c_break is true
      if yes,
        get the next "keystroke" (getch() in C is ok here!), this overreads
        the break scancode
        reset the c_break flag
        if you want, set some other flag to signal c_break was hit
      else
        do nothing
    and complete
  When the original int09h runs and detects ctrl-break or ctrl-C was pressed,
  it calls one of the DOS ctrl-break handlers (int19h or int24h, but please
  do not beat me if that's wrong, I have no doc handy...) which normally
  set a DOS internal flag which causes DOS to terminate your program on
  thenext int21h.
  So the only thing which remains to do is to replace these two ctrl-break
  interrupts with your own handler, simply setting the c_break flag inspected
  by your own keyboard handler.
  It is important NOT to call the original ctrl-break handlers from your
  own, because otherwise DOS would show up with a nasty "^C" string later.

I hope I go it half right...

Bye
  Patrick