[Mesa-dev] [PATCH 1/7] util: add MAYBE_UNUSED for config dependent variables

[Chad Versace]

On Tue 19 Apr 2016, Emil Velikov wrote:
> On 19 April 2016 at 19:38, Ian Romanick <idr at freedesktop.org> wrote:
> > On 04/19/2016 07:48 AM, Emil Velikov wrote:
> >> On 18 April 2016 at 19:01, Ian Romanick <idr at freedesktop.org> wrote:
> >>> On 04/18/2016 08:06 AM, Emil Velikov wrote:
> >>>> On 18 April 2016 at 04:43, Francisco Jerez <currojerez at riseup.net> wrote:
> >>>>> Grazvydas Ignotas <notasas at gmail.com> writes:
> >>>>>
> >>>>>> On Sun, Apr 17, 2016 at 2:50 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> >>>>>>> On 16 April 2016 at 02:00, Grazvydas Ignotas <notasas at gmail.com> wrote:

> >>>>>>>> +#define MAYBE_UNUSED UNUSED
> >>>>>>>> +
> >>>>>>> Hell yeah !
> >>>>>>>
> >>>>>>> A thing that comes to mind ... a while back we've been wondering about
> >>>>>>> (re)naming these just the the way we do in the kernel. Namely
> >>>>>>> __maybe_unused in this case. Can you give that one a try and link a
> >>>>>>> branch.
> >>>>>>
> >>>>>> I hope you mean something like this?
> >>>>>> https://github.com/notaz/mesa/commits/warnings
> >>>>>>
> >>>>>
> >>>>> You guys know that in standard C any identifier (including a
> >>>>> preprocessor define) starting with double underscore is reserved for the
> >>>>> implementation and causes the program's behavior to be undefined?  The
> >>>>> kernel is kind of part of the implementation so they can do whatever
> >>>>> they want, but it seems dubious to do the same in a userspace library.
> >>>>> How about you use a single (or no) underscore if people prefer the
> >>>>> lowercase spelling?
> >>>>>

FYI, systemd uses a nice convention for attributes that is nicer on the
eyes than ALL_CAPS and doesn't violate the standard with
double-underscore. systemd declares attributes as _lower_case_.

For example:

  #define _maybe_unused_ __attribute__((unused))

Anyway, the original path with ALL_CAPS is
Reviewed-by: Chad Versace <chad.versace at intel.com>