svn commit: r334702 - head/sys/sys

[Benjamin Kaduk]

On Wed, Jun 6, 2018 at 6:35 AM, Ravi Pokala <rpokala at freebsd.org> wrote:

> Hi Mateusz,
>
> -----Original Message-----
> From: <owner-src-committers at freebsd.org> on behalf of Mateusz Guzik
> <mjg at FreeBSD.org>
> Date: 2018-06-06, Wednesday at 01:08
> To: <src-committers at freebsd.org>, <svn-src-all at freebsd.org>, <
> svn-src-head at freebsd.org>
> Subject: svn commit: r334702 - head/sys/sys
>
> > ...
> >  #ifdef _KERNEL
> >  #define      malloc(size, type, flags) ({
>       \
>
> Now that I'm taking another look at this, I'm confused as to why the
> entire macro expansion is inside parentheses? (The braces make sense, since
> this is a block with local variables which need to be contained.)
>

This is a gcc (and clang) extension to allow the macro body to be a code
block -- standard C gets unhappy with just the curly braces.
https://gcc.gnu.org/onlinedocs/gcc/Statement-Exprs.html is a maybe-relevant
page that google found me.

-Ben