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Path: utzoo!mnetor!seismo!rutgers!ames!hc!hi!kurt
From: kurt@hi.UUCP (Kurt Zeilenga)
Newsgroups: comp.lang.c
Subject: Re: Returning a value from ?:
Message-ID: <7652@hi.UUCP>
Date: Sat, 30-May-87 16:29:26 EDT
Article-I.D.: hi.7652
Posted: Sat May 30 16:29:26 1987
Date-Received: Mon, 1-Jun-87 06:37:55 EDT
References: <7555@brl-adm.ARPA>
Reply-To: kurt@hi.UUCP (Kurt Zeilenga)
Organization: U. of New Mexico, Albuquerque
Lines: 30

In article <7555@brl-adm.ARPA> DAVE%UWF.BITNET@wiscvm.wisc.EDU writes:
>
>All,
>    Well, my recent probs with printf are solved, by linking with LCM
>ahead of LC, as suggested.  Thanks.
>    Next in line, I just (yesterday) got a copy of Turbo C, and was
>trying out some old programs on it.  It works mostly like a champ, but
>I ran across a small bug.  It goes like this:
>
>     (f(a) * f(p) > 0) ? (a = p) : (b = p);
>
>with the function f() being defined elsewhere, and with all things being
>defined as double.  I got it to work by splitting up the ? : up into
>an if ... else, but it worked w/o hitch under Lattice 3.0.  Is the above

By "worked" do you mean compiled or running with "proper" results.

>statement not valid C code?

The above statement is valid.  However, beware of side effects and order
of evaulation, you are not guaranteed the order of the evaulation of
f(a) * f(p).  Ie: some compilers may do f(a) first and then f(p), others
may do f(p) first.  K&R allows the compiler to rewrite such expressions.
Could this be the root of the evil?

Hope this helps....
-- 
	Kurt Zeilenga	 (zeilenga@hc.dspo.gov)		I want my talk.flame!

	"So long, Mom, I'm off to kill a commie..."