From: Christoph Hellwig <hch@infradead.org>
To: "Robert P. J. Day" <rpjday@mindspring.com>
Cc: Linux kernel mailing list <linux-kernel@vger.kernel.org>,
Randy Dunlap <randy.dunlap@oracle.com>,
trivial@kernel.org
Subject: Re: [PATCH] Documentation: Explain a second alternative for multi-line macros.
Date: Mon, 1 Jan 2007 14:20:20 +0000 [thread overview]
Message-ID: <20070101142020.GA16425@infradead.org> (raw)
In-Reply-To: <Pine.LNX.4.64.0612311430370.18269@localhost.localdomain>
On Sun, Dec 31, 2006 at 02:32:25PM -0500, Robert P. J. Day wrote:
> + (a) Enclose those statements in a do - while block:
> +
> + #define macrofun(a, b, c) \
> + do { \
> + if (a == 5) \
> + do_this(b, c); \
> + } while (0)
nitpick, please don't add an indentaion level for the do {. Do this
should look like:
#define macrofun(a, b, c) \
do { \
if (a == 5) \
do_this(b, c); \
} while (0)
> + (b) Use the gcc extension that a compound statement enclosed in
> + parentheses represents an expression:
> +
> + #define macrofun(a, b, c) ({ \
> if (a == 5) \
> do_this(b, c); \
> - } while (0)
> + })
I'd rather document to not use this - it makes the code far less
redable. And it's a non-standard extension, something we only
use if it provides us a benefit which it doesn't here.
next prev parent reply other threads:[~2007-01-01 14:20 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-31 19:32 [PATCH] Documentation: Explain a second alternative for multi-line macros Robert P. J. Day
2006-12-31 19:45 ` Muli Ben-Yehuda
2006-12-31 19:49 ` Robert P. J. Day
2006-12-31 20:09 ` Muli Ben-Yehuda
2006-12-31 20:03 ` Randy Dunlap
2006-12-31 20:13 ` Robert P. J. Day
2007-01-01 2:40 ` Segher Boessenkool
2007-01-01 3:23 ` Randy Dunlap
2007-01-01 4:31 ` Segher Boessenkool
2007-01-01 4:30 ` Randy Dunlap
2007-01-01 15:37 ` Jan Engelhardt
2007-01-01 17:51 ` Segher Boessenkool
2007-01-01 19:11 ` Jan Engelhardt
2007-01-01 8:26 ` Robert P. J. Day
2007-01-01 14:20 ` Christoph Hellwig [this message]
2007-01-01 14:25 ` Robert P. J. Day
2007-01-01 16:14 ` Randy Dunlap
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