Re: macro conflict

Roman Zippel (zippel@linux-m68k.org)
Fri, 24 Aug 2001 01:35:38 +0200


Hi,

"Magnus Naeslund(f)" wrote:

> > min(x,y) = ({typeof((x)) __x=(x), __y=(y); (__x < __y) ? __x : __y})
> >
> > That gets you the correct "evaluate the args once" semantics and gives
> > you control over typing (the comparison is done in the type of the
> > first argument) and we don't have to change a zillion drivers.
> >
> > (typeof() is a gcc extension.)

({...}) is also gcc extension.

> But then again, how do you know it's the type of x we want, maybe we want
> type of y, that is and signed char (not an int like x).
> Talk about hidden buffer overflow stuff :)

That's the reason I'm using this macro for affs:

#define MIN(a, b) ({ \
typeof(a) _a = (a); \
typeof(b) _b = (b); \
_a < _b ? _a : _b; \
})

I need a very good reason to use something else, so far I'm unconvinced.

bye, Roman
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