Path: utzoo!yunexus!geac!daveb
From: daveb@geac.UUCP (David Collier-Brown)
Newsgroups: comp.lang.c
Subject: Re: noalias comments to X3J11
Message-ID: <2518@geac.UUCP>
Date: 31 Mar 88 03:04:29 GMT
Article-I.D.: geac.2518
Posted: Wed Mar 30 22:04:29 1988
References: <12578@brl-adm.ARPA> <1988Mar25.172355.348@utzoo.uucp> <597@tuvie>
Reply-To: daveb@geac.UUCP (David Collier-Brown)
Organization: The Geac "My CP/M machine has signals" Department
Lines: 28


In article <1988Mar25.172355.348@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
| Interrupt routines are almost by definition esoteric, not to mention highly
| machine-specific.

In article <597@tuvie> rcvie@tuvie.UUCP (D. Weickert) writes:
| Signal handlers will be at least very similar to interrupt routines. Still it
| does not seem to be esoteric to me, if I set a flag in such a handler. And now
| please tell me, how to tell the compiler it must not `optimize' the access to
| this flag?

Well, they're interrupt-like in style, but not always in nature.  It
is probably true that some machine and operating system somewhere on
this net has signals which run asynchronously to the rest of the
program, but in general they are executed in the normal context of
a C program, as a (simulated, perhaps) subroutine call and strictly
synchronously with the rest of the program.  The CP/M machine I'm
using to write this posting from has signal handlers and dispatchers
in the great majority of its C programs: written by Drew Sullivan
(drew@lethe) many moons ago.

 And you don't, therefore have to do anything to the said flag
variable.  Except make it accessable.
-- 
 David Collier-Brown.                 {mnetor yunexus utgpu}!geac!daveb
 Geac Computers International Inc.,   |  Computer Science loses its
 350 Steelcase Road,Markham, Ontario, |  memory (if not its mind) 
 CANADA, L3R 1B3 (416) 475-0525 x3279 |  every 6 months.