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From: David Brownell <david-b@pacbell.net>
To: linux-pm@lists.linux-foundation.org
Subject: Re: [linux-pm] [PATCH RFC] introduce pm_call() macro to get rid of most	#ifdef CONFIG_PM
Date: Mon, 3 Mar 2008 14:56:38 -0800
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Cc: Pavel Machek <pavel@ucw.cz>, Anton Vorontsov <cbouatmailru@gmail.com>,
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On Monday 03 March 2008, Pavel Machek wrote:
> > +/* avoid `defined but not used' warning */
> > +#define pm_call(x) ((x) - 1 ? NULL : NULL)
> > +#endif /* CONFIG_PM */
> > +
> 
> This is evil.

Ugly, yes.  It might merit some casts too.


> Maybe your gcc is smart enough to optimize this away, 
> but I'm not sure mine is.

It'll be a constant expression; it certainly ought to be.