[Mesa-dev] [PATCH] util: Unbreak usage of assert()/debug_assert() inside expressions.

[Patrick Baggett]

On Fri, Dec 12, 2014 at 10:17 AM, Roland Scheidegger <sroland at vmware.com>
wrote:

> Am 12.12.2014 um 15:09 schrieb Jose Fonseca:
> > From: José Fonseca <jfonseca at vmware.com>
> >
> > f0ba7d897d1c22202531acb70f134f2edc30557d made debug_assert()/assert()
> > unsafe for expressions, but only now with u_atomic.h started to rely on
> > them for Windows this became an issue.
> >
> > This fixes non-debug builds with MSVC.
> > ---
> >  src/gallium/auxiliary/util/u_debug.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/src/gallium/auxiliary/util/u_debug.h
> b/src/gallium/auxiliary/util/u_debug.h
> > index badd5e2..4c22fdf 100644
> > --- a/src/gallium/auxiliary/util/u_debug.h
> > +++ b/src/gallium/auxiliary/util/u_debug.h
> > @@ -185,7 +185,7 @@ void _debug_assert_fail(const char *expr,
> >  #ifdef DEBUG
> >  #define debug_assert(expr) ((expr) ? (void)0 :
> _debug_assert_fail(#expr, __FILE__, __LINE__, __FUNCTION__))
> >  #else
> > -#define debug_assert(expr) do { } while (0 && (expr))
> > +#define debug_assert(expr) (void)(0 && (expr))
> >  #endif
> >
> >
> >
>

Just for my own education, can someone explain what the need for
`debug_assert()` to have any expansion of `expr` at all? Rather, what
breaks with something like:

  #define debug_assert(expr) ((void)0)
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