On 14/06/18 20:02 +0300, Ville Voutilainen wrote:
On 14 June 2018 at 19:57, Jonathan Wakely <jwak...@redhat.com> wrote:
[macro.names]/2 forbids #defining macros with the same names as the
standard attributes.
The programs Martin shows as examples are not valid.
But nonnull isn't a standard attribute though. So we can't use
[[gnu::xxx]] attributes in libstdc++ and have to use __attribute__
instead.
Oops, indeed. But for gnu-attributes, surely we can decide whatever we
want about what's
valid and what's not?
We could say that #defining 'nonnull' and/or 'gnu' as a macro is
undefined, but then programs that the standard says are valid would
fail to compile, and we'd be a non-conforming implementation.
We can use __attribute__(__nonnull__)) so that we accept those
programs (and be a conforming implementation). Why would we choose to
be non-conforming when we don't have to?
We can use [[gnu::__nonnull__]] but that would still reject programs
that #define gnu so maybe we want the front-end to also recognise
__gnu__ as our attribute namespace.
