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

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> 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?

> and if we suffix with ULL only 64-bits constant, it would be a call to 
> forget when moving from a 32-bit to 64-bit value.

Well, I don't view this as a good reason, but you're the maintainer
of that code ...

Jan


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