Path: utzoo!attcan!uunet!dg!archive!bruce
From: bruce@archive.rtp.dg.com (Bruce Kahn)
Newsgroups: comp.sys.ibm.pc.programmer
Subject: Re: Avoiding ^C
Message-ID: <577@dg.dg.com>
Date: 28 Jun 90 14:11:03 GMT
References: <10688@spool.cs.wisc.edu>
Sender: root@dg.dg.com
Reply-To: bruce@archive.rtp.dg.com (Bruce Kahn)
Organization: Data General Corporation, Research Triangle Park, NC
Lines: 18

In article <10688@spool.cs.wisc.edu>, so@brownie.cs.wisc.edu (Bryan So) writes:
|> I have tried to trap the Ctrl-Break and Ctrl-C interrupts by
|> "signal", "ctrlbrk" in Turbo C and installing my own 0x23 handler.
|> But there seems to be no way to prevent "^C" from printing out to
|> the screen.  Can somebody explain a way to do it?  Thanks.
|> 
|> Bryan

  The only way that Ive found to prevent the annoying ^C from being displayed
is to NOT use the standard printf calls.  I found that I had to issue direct
BIOS write calls and bypass DOS.  The reason being (I was told a long long
time ago) that DOS allows you to insert your own INT23 handler but it stil
sets a 'break' flag internally and when it does any screen I/O it checks the
flag; if it is set it inserts a ^C into the buffer and clears the flag.
  If you need more specifics I can dig out my code and tell you what exactly I
did (it may have been I issued INT21, AH=10H calls myself)...

					Bruce (bruce@archive.rtp.dg.com)