Re: [Xen-devel] question regarding gnu-isms

[Aron Griffis <aron@xxxxxx>]

Hi Anthony,

Thanks for the explanation of the struct initialization.  Regarding
the second one, though...

Anthony Liguori wrote: [Thu Apr 27 2006, 07:04:01PM EDT]
> Aron Griffis wrote:
> >    #define xen_create_contiguous_region(vstart, order, address_bits) 
> >    ({0;})
> 
> This is a really common one that lets you make statements into 
> expressions.
...
>
> #define min(a, b) ({int lhs = a; int rhs = b; (lhs < rhs) ? lhs : rhs;})

That makes sense for the example you gave, but how does it apply to
the definition in question?  Is there any difference between ({0;})
and (0) or even 0?

> All of these are documented in the GCC Info page (see the section on
> C Extensions).

:-)  I read that before posting, so I was familiar with the purpose of
enclosing compound statements in expressions.  But I'll reread in case
there's something I missed regarding the interpretation of ({0;})

Regards,
Aron

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel