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From: Roman Zippel <zippel@linux-m68k.org>
To: "Magnus Naeslund(f)" <mag@fbab.net>
Cc: raybry@timesn.com, Tim Walberg <twalberg@mindspring.com>,
	linux-kernel@vger.kernel.org
Subject: Re: macro conflict
Date: Fri, 24 Aug 2001 01:35:38 +0200	[thread overview]
Message-ID: <3B859349.95F09EB1@linux-m68k.org> (raw)
In-Reply-To: <20010823143440.G20693@mindspring.com> <3B85615A.58920036@timesn.com> <03fc01c12c10$8155b060$020a0a0a@totalmef>

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

  parent reply	other threads:[~2001-08-23 23:36 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-08-23 19:03 macro conflict J. Imlay
2001-08-23 19:21 ` Alan Cox
2001-08-23 19:34 ` Tim Walberg
2001-08-23 20:01   ` Alan Cox
2001-08-23 20:02   ` raybry
2001-08-23 20:16     ` Magnus Naeslund(f)
2001-08-23 20:27       ` Alan Cox
2001-08-23 20:29         ` Magnus Naeslund(f)
2001-08-23 23:18       ` Andrew Cannon
2001-08-23 23:37         ` Magnus Naeslund(f)
2001-08-23 23:35       ` Roman Zippel [this message]
2001-08-24  1:42     ` Camiel Vanderhoeven
2001-08-24 13:03 ` David Woodhouse
2001-08-24 13:15   ` Keith Owens
2001-08-24 13:17     ` David Woodhouse
2001-08-24 14:20       ` Bill Pringlemeir
2001-08-24 21:17         ` Roman Zippel
2001-08-24 13:34   ` Richard B. Johnson
2001-08-24 18:20     ` David Wagner
2001-08-24 17:25   ` Alex Bligh - linux-kernel
2001-08-24 17:34   ` David Woodhouse
2001-08-24 18:12     ` Bill Pringlemeir

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