From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.fraser@eu.citrix.com>
Subject: Re: open-coded offsetof() in xen/include/public/ring.h
Date: Tue, 23 Feb 2010 14:30:51 +0000
Message-ID: <C7A9971B.AFB7%keir.fraser@eu.citrix.com>
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To: Jan Beulich <JBeulich@novell.com>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
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On 23/02/2010 14:07, "Jan Beulich" <JBeulich@novell.com> wrote:

> Using gcc 4.5 we're seeing a build failure of the netfront driver due to
> its use of the __RING_SIZE() macro in the size specification of array
> members of struct netfront_info. Since the use of pointer types in
> integer constant expressions is an extension (albeit one - for the
> specific form used here - so far supported by all compilers Xen
> appears to be used with, and certainly all of the ones I was able to
> test), I wonder whether requiring offsetof() to be defined in order
> to use __RING_SIZE (or really a clone thereof usable in constant
> expressions, since in that case a type rather than a pointer ought to
> be passed in) would be acceptable.

That would be acceptable. We already require some things like stdint types
to be pre-defined for example.

 -- Keir