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From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.std.c
Subject: Re: Voids in a comma expression
Keywords: voids comma operator
Message-ID: <16482@smoke.brl.mil>
Date: 22 Jun 91 04:46:11 GMT
References: <34405@shamash.cdc.com>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 16

In article <34405@shamash.cdc.com> paul@u02.svl.cdc.com (Paul Kohlmiller) writes:
>extern void foo(int x);
>main() {
>int j=3;
>int i;
>j=(i=4,foo(i),i++);
>}
>The diagnostic claims that ANSI disallows the void expression foo(i) in the
>command expression.

Well, the compiler is wrong.  The only thing wrong with the code example,
its failure to return a value from main(), has nothing to do with its use
of the comma operator.

The rest of your question I found totally confusing.  Perhaps you should
not let a buggy compiler influence your understanding of the language.