Path: utzoo!mnetor!uunet!husc6!tut.cis.ohio-state.edu!lvc
From: lvc@tut.cis.ohio-state.edu (Lawrence V. Cipriani)
Newsgroups: comp.lang.c
Subject: Re: volatile
Message-ID: <9176@tut.cis.ohio-state.edu>
Date: 30 Mar 88 04:15:01 GMT
References: <12578@brl-adm.ARPA> <1988Mar25.172355.348@utzoo.uucp> <588@imagine.PAWL.RPI.EDU> <1988Mar29.004454.2867@utzoo.uucp> <134@wyse.wyse.com>
Organization: The Ohio State University Dept of Computer and Information Science
Lines: 28

In article <134@wyse.wyse.com> mikew@wyse.UUCP (Mike Wexler) writes:
>I would disagree that is isn't possible to write portable code that requires
>volatiles. An example(possibly the only one), is the use of System V
>or Berkeley shared memory. ...

I might not understand volatile correctly but this might also be an
example:

	volatile int customer_changeable_var = 0;

	main( )
		...

	if (customer_chageable_var != 0)
	{
		...
	}

If the volatile were dropped off, the compiler would be free to
optimize out the "impossible" code.  A customer changeable global
variable is a handy way for implementing optional features that
customers may or may not want; especially in programs that should
avoid disk i/o.

-- 
Larry Cipriani, AT&T Networks Systems (day) Ohio State University (night)
Domain: lvc@tut.cis.ohio-state.edu
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