Re: [Xen-devel] [PATCH] pub-headers: reduce C99 dependencies

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Thu, Sep 29, 2016 at 12:22:37PM -0700, Julien Grall wrote:
> 
> 
> On 29/09/2016 12:11, Julien Grall wrote:
> >Hi Jan,
> >
> >On 28/09/2016 23:04, Jan Beulich wrote:
> >>>>>On 28.09.16 at 21:42, <julien.grall@xxxxxxx> wrote:
> >>>Hi Jan,
> >>>
> >>>On 28/09/2016 05:00, Jan Beulich wrote:
> >>>>For consumers not using (fully) C99-aware compilers, limit the number
> >>>>of places where tweaking of the headers would be necessary: Introduce
> >>>>and use xen_mk_ullong(), allowing its helper macro to be overridden at
> >>>>once.
> >>>>
> >>>>For now don't touch public/io/, which also has a few offenders.
> >>>>
> >>>>The need to include xen.h in hvm/e820.h demonstrates that it is a bad
> >>>>idea to include public headers first thing - arch/x86/hvm/mtrr.c needs
> >>>>adjustment just because of this.
> >>>>
> >>>>Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
> >>>>---
> >>>>I wonder why all those ARM constants carry the ULL suffix despite only
> >>>>two of them actually exceeding 32 significant bits.
> >>>
> >>>I am not the author of the code, but I think it was to declare all the
> >>>constants of a given set uniformed.
> >>>
> >>>For instance all the GUEST_* constants are used to define the layout of
> >>>the guest. This may be shuffle in this future (this is not part of ABI)
> >>
> >>Oh, they're in a Xen/tools only section (the #endif could really be
> >>annotated to help spot this) - in that case I could as well leave them
> >>alone. Any preference?
> >
> >Correct. I can send a patch to annotate the #endif.
> 
> It looks like that I did not reply to your question. Do we expect the
> toolstack to always C99 standard? If not, then we should keep the
> xen_mk_ullong.
> 
> I am fine either way.
> 

We have -std=gnu99 in top-level Config.mk -- both xen and tools will be
built with that.

Wei.

> Cheers,
> 
> -- 
> Julien Grall

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