From mboxrd@z Thu Jan  1 00:00:00 1970
From: Julien Grall <julien.grall@linaro.org>
Subject: Re: [PATCH for Xen 4.5] xen/arm: Add support for GICv3
	for domU
Date: Tue, 18 Nov 2014 15:26:05 +0000
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To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: ian.campbell@citrix.com, Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com>, tim@xen.org, stefano.stabellini@citrix.com, Jan Beulich <JBeulich@suse.com>, xen-devel@lists.xenproject.org, Daniel De Graaf <dgdegra@tycho.nsa.gov>
List-Id: xen-devel@lists.xenproject.org

On 11/18/2014 03:10 PM, Ian Jackson wrote:
> Julien Grall writes ("Re: [PATCH for Xen 4.5] xen/arm: Add support for GICv3 for domU"):
>> I need to create an empty structure. Is the dummy field really needed?
> 
> Empty structs are a gcc extension (`(gcc-4.4) Empty Structures').  I
> would be very surprised if clang didn't support them too.

AFAIK, clang doesn't complain about empty structures.

> AIUI our policy, gcc extensions are fine except in the Xen public
> headers.

We have at least 2 "empty" structure on the ARM public header.

>> If so, did you meant?
>>
>> struct
>> {
>>    int :0;
>> }
> 
> Whatever you do, don't do this!

Would something like below be better?

struct
{
  int dummy:1
};

Regards,

-- 
Julien Grall