svn commit: r329910 - head/sys/cddl/contrib/opensolaris/uts/common/sys
Alan Somers
asomers at freebsd.org
Sun Feb 25 14:18:38 UTC 2018
On Sun, Feb 25, 2018 at 6:52 AM, Dimitry Andric <dim at freebsd.org> wrote:
> On 24 Feb 2018, at 17:01, Alan Somers <asomers at freebsd.org> wrote:
> >
> > Author: asomers
> > Date: Sat Feb 24 16:01:21 2018
> > New Revision: 329910
> > URL: https://svnweb.freebsd.org/changeset/base/329910
> >
> > Log:
> > Implement CTASSERT using _Static_assert
> >
> > Prevents warnings about "unused typedef" with GCC-6
> >
> > Reported by: GCC-6
> > MFC after: 18 days
> > X-MFC-With: 329722
> >
> > Modified:
> > head/sys/cddl/contrib/opensolaris/uts/common/sys/debug.h
> >
> > Modified: head/sys/cddl/contrib/opensolaris/uts/common/sys/debug.h
> > ============================================================
> ==================
> > --- head/sys/cddl/contrib/opensolaris/uts/common/sys/debug.h Sat Feb
> 24 15:13:20 2018 (r329909)
> > +++ head/sys/cddl/contrib/opensolaris/uts/common/sys/debug.h Sat Feb
> 24 16:01:21 2018 (r329910)
> > @@ -133,8 +133,8 @@ _NOTE(CONSTCOND) } while (0)
> > #ifndef CTASSERT
> > #define CTASSERT(x) _CTASSERT(x, __LINE__)
> > #define _CTASSERT(x, y) __CTASSERT(x, y)
> > -#define __CTASSERT(x, y) \
> > - typedef char __compile_time_assertion__ ## y [(x) ? 1 : -1]
> > +#define __CTASSERT(x, y) \
> > + _Static_assert((x), "Static assert failed at " #y)
> > #endif
> >
> > #ifdef _KERNEL
>
> Note that the trick with the negatively indexed array is to support
> older versions of gcc, which did not yet recognize _Static_assert. It
> looks like this was added in gcc 4.6.
>
> -Dimitry
>
>
sys/cdefs.h defines _Static_assert similarly on GCC 4.3-4.5, and defines it
to nothingness on GCC-4.2. So we should be covered for all compilers that
we care about.
-Alan
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