Re: [linux-pm] [PATCH RFC] introduce pm_call() macro to get rid ofmost #ifdef CONFIG_PM

From: Pavel Machek
Date: Mon Mar 03 2008 - 18:16:25 EST


Hi!


> > > +/* 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.

Well, we have just fooler compiler to think that x is used, and now we
want it to realize that x is unused and compile it out?

Maybe it is smart enough, but...
Pavel
--
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