Path: utzoo!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!uunet!mcsun!unido!sbsvax!roeder
From: roeder@sbsvax.cs.uni-sb.de (Edgar Roeder)
Newsgroups: comp.sys.atari.st
Subject: Re: break
Summary: try catch
Keywords: RTX job control vi ksh csh SIGSTOP _main cli isr
Message-ID: <4252@sbsvax.cs.uni-sb.de>
Date: 7 May 90 15:10:59 GMT
References: <3060@ultb.isc.rit.edu>
Organization: Universitaet des Saarlandes, Saarbruecken, W-Germany
Lines: 45

In article <3060@ultb.isc.rit.edu>, jdb9608@ultb.isc.rit.edu (J.D. Beutel) writes:
> 
> Does anybody know how break (i.e., ^C) works on the ST?
> Is it something in TOS?  (I wouldn't think so since I don't
> remember hearing about it, and I know some programs don't break.)

Yes it is done by TOS. But only the GEMDOS functions Cconin/Cconrs/Cconout and
Cconws use it. If a program uses BIOS for terminal-i/o, it has to do the ^C
trapping itself.

> and I miss multi-tasking and job control.  So, thinking about
> device drivers, SIGSTOP, and the like, I really should understand ^C.

Have you seen the demo of Master? This shell has job-control (but no multi-
tasking). Jobs are created by system("-i") from C-Code, by 'if exec "-i"' in
a batchfile or you can start your program as 'program args |' and then input
'!-i<Return>' at the prompt after any full screen of output. Stopped jobs may
be restarted by '%<job-id>' in any order.

> I suppose I could just have the cli slip in an isr to monitor
> whatever tty-type input devices, and grap any ^Z that comes along,
> but there'll probably be complications if I don't understand 
> what else is going on.

The catch-program posted to comp.binaries.atari.st does it just this way. You
can install it in your auto-folder (catch.mmx has to be renamed to catch.prg)
and let it catch any ^C/^Z/^\-keypress at any time (even if your program is in
an endless loop). If ^C is pressed, you are asked wether you want to break or
continue. If ^Z is pressed, an eventually installed shell (at _shell_p) is
called interactively. See catch.doc for more uses of this program.
If you want to know more about ^C-trapping, you can also look up the
documentation for etv_term (the terminate-vector of GEMDOS).

> J. David Beutel  11011011  jdb9608@cs.rit.edu      "I am, therefore I am."

Hope this helps!

	- Edgar
-- 

Mail:  Edgar R\"oder			E-Mail: roeder@cs.uni-sb.de
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