Re: [RFC (fix for 5.0?)] block/io: do not do pointer arithmetic on void *

[Eric Blake]

On 3/18/20 9:26 AM, Daniel P. Berrangé wrote:
> On Wed, Mar 18, 2020 at 05:22:53PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> > ---
> >
> > Hi all!
> >
> > C standard doesn't allow pointer arithmetic on void *.
> > Still, gcc allows it as an extension:
> >   https://gcc.gnu.org/onlinedocs/gcc-4.8.0/gcc/Pointer-Arith.html
> >
> > I can create a series of patches like this. Do we need it?
>
> I don't think so, we only care about gcc & clang.

Still, if all supported compilers support the extension, then our 
CODING_STYLE.rst should mention that it is safe to rely on the extension.

> > Also, where is documented which compilers are supported by Qemu?
>
> It is checked in configure - gcc 4.8 or clang 3.4 or xcode clang 5.1


--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
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