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From: Randy Dunlap <randy.dunlap@oracle.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: "Robert P. J. Day" <rpjday@mindspring.com>,
	Muli Ben-Yehuda <muli@il.ibm.com>,
	Linux kernel mailing list <linux-kernel@vger.kernel.org>,
	trivial@kernel.org
Subject: Re: [PATCH] Documentation: Explain a second alternative for multi-line macros.
Date: Sun, 31 Dec 2006 19:23:28 -0800	[thread overview]
Message-ID: <45987EB0.1020505@oracle.com> (raw)
In-Reply-To: <66cc662565c489fa9e604073ced64889@kernel.crashing.org>

Segher Boessenkool wrote:
>>> In this case, the second form
>>> should be used when the macro needs to return a value (and you can't
>>> use an inline function for whatever reason), whereas the first form
>>> should be used at all other times.
>>
>> that's a fair point, although it's certainly not the coding style
>> that's in play now.  for example,
>>
>>   #define setcc(cc) ({ \
>>     partial_status &= ~(SW_C0|SW_C1|SW_C2|SW_C3); \
>>     partial_status |= (cc) & (SW_C0|SW_C1|SW_C2|SW_C3); })
> 
> This _does_ return a value though, bad example.

Where does it return a value?  I don't see any uses of it
in arch/i386/math-emu/* that use it as returning a value.

And with a small change to put it inside a do-while block
instead of ({ ... }), it at least builds cleanly.
I expected some complaints.

-- 
~Randy

  reply	other threads:[~2007-01-01  3:37 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 [this message]
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
2007-01-01 14:25   ` Robert P. J. Day
2007-01-01 16:14     ` Randy Dunlap

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