Date: Fri, 27 Jul 2012 23:41:10 -0700 From: Tim Kientzle <tim@kientzle.com> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: current@freebsd.org Subject: Re: (void)foo or __unused foo ? Message-ID: <B86B2D65-25E3-4887-9203-AFED9563CE51@kientzle.com> In-Reply-To: <20120727093824.GB56662@onelab2.iet.unipi.it> References: <20120727093824.GB56662@onelab2.iet.unipi.it>
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On Jul 27, 2012, at 2:38 AM, Luigi Rizzo wrote:
>=20
> The alternative way to avoid an 'unused' warning from the compiler
> is an empty statement
>=20
> (void)foo;
>=20
> that the compiler hopefully optimizes away.
I learned the void-cast convention many years ago.
I used it throughout the libarchive code and have yet to
run into any problems. I always use it in exactly this form
(with the exact comment here) so that I can easily search
on it:
int foo(int a) {
(void) a; /* UNUSED */
=85
}
I agree with PHK that it would be nice to express this
intent in a way that static checkers could verify. I also
agree that having static checkers interpret comments is Evil.
But I have yet to see any alternative that was as
straightforward and widely-supported as this one.
Every other viable alternative seems to require tangled
clumps of macros.
Tim
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