Re: [head tinderbox] failure on arm/arm

From: Ruslan Ermilov <ru_at_freebsd.org>
Date: Sun, 12 Nov 2006 20:14:37 +0300
On Sun, Nov 12, 2006 at 04:59:04PM +0000, Nicholas Clark wrote:
> On Sun, Nov 12, 2006 at 06:57:23PM +0300, Ruslan Ermilov wrote:
> > So your sizeof() argument, well...  I don't understand it and it
> > doesn't make things clearer at least to me.  I still believe this
> > is bug in GCC that the alignment requirement is so high for a
> > "struct foo { char x; }" (there's no real reason for this!).
> 
> It is no bug in GCC. ANSI C gives extreme flexibility for the compiler to
> align (or pad) structures. The assumptions in the code you presented are not
> portable. The problem tends to be that ARM is the only common platform that
> does structure alignment this way, so tends to trip up a lot of code that
> has worked just fine in many other places.
> 
> There is a lot more detail in
> http://netwinder.osuosl.org/users/b/brianbr/public_html/alignment.html
> including how gcc's __packed__ extention can be used to tell gcc to align
> structures in different ways.
> 
Thanks!  Item 2 at this URL has an answer to my question.


Cheers,
-- 
Ruslan Ermilov
ru_at_FreeBSD.org
FreeBSD committer

Received on Sun Nov 12 2006 - 16:14:44 UTC

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