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Date: Fri, 9 Mar 2007 09:35:54 +0100
From: Jarek Poplawski <jarkao2@o2.pl>
To: Christoph Hellwig <hch@infradead.org>,
       Rusty Russell <rusty@rustcorp.com.au>,
       lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] Use more gcc extensions in the Linux headers
Message-ID: <20070309083554.GB1662@ff.dom.local>
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On 09-03-2007 08:52, Christoph Hellwig wrote:
> On Fri, Mar 09, 2007 at 04:56:32PM +1100, Rusty Russell wrote:
...
>> +#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0])			      \
>> +	+ sizeof(typeof(int[1 - 2*!!__builtin_types_compatible_p(typeof(arr), \
>> +		 typeof(&arr[0]))]))*0)
> 
> This needs a comment explaning why we're doing this, and maybe a little
> explanation of the combination of gcc magic and C trickery used to implement
> it to the brave non-uberhacker people trying to understand linux headers.

...and to deprive them of all the pleasure of contemplating...

Jarek P.