Re: [Qemu-devel] [PATCH 2/5] CODING_STYLE: add C type rules

[Anthony Liguori]

On 08/17/2010 02:43 PM, Jes Sorensen wrote:
> On 08/17/10 21:24, malc wrote:
>    
> > On Tue, 17 Aug 2010, Jes Sorensen wrote:
> >
> >      
> > > On 08/17/10 20:55, malc wrote:
> > >        
> > > > On Tue, 17 Aug 2010, Blue Swirl wrote:
> > > >          
> > > > > > The other thing that might be worth mentioning in the int/long section
> > > > > > is that long is complicated in broken development environments such as
> > > > > > Windows where it is only 32 bit :(
> > > > > >              
> > > > There's absolutely nothing broken about LLP64 it's as valid as any other
> > > > ABI. (That's to Jes)
> > > >          
> > > Well it works if you program for it, but it still doesn't make it any
> > > good when you can't keep a pointer in a long to apply arithmetic to it.
> > > Anyway point with the documentation is to make it clear that we rely on
> > > being able to do long foo = (long)ptr;
> > >        
> > Which isn't (and never was) sanctioned by any standard, IOW not good.
> >      
> Well maybe this is where the problem is. Not being able to do this means
> that we need a special integer type to cover this case if we wanted to
> work on win64. Switching to long long would generate bad code on 32 bit
> archs so thats not an option.
>    

FWIW, that type is intptr_t and it was introduced in C99.

Regards,

Anthony Liguori

> Depending on your viewpoint it is either it not being a standard that is
> bad, or the LLP64 that is bad.
>
> Anyway this is personal preference.
>
> Jes
>
>
>