On 12 October 2016 at 12:51, Aaron Ballman <aa...@aaronballman.com> wrote: > On Wed, Oct 12, 2016 at 6:55 AM, Jonathan Wakely <c...@kayari.org> wrote: >> The SD-6 draft has >> >> [3.3.6] Example >> >> This demonstrates a way to use the attribute [[deprecated]] only if it >> is available. >> >> #ifdef __has_cpp_attribute >> # if __has_cpp_attribute(deprecated) >> # define ATTR_DEPRECATED(msg) [[deprecated(msg)]] >> # else >> # define ATTR_DEPRECATED(msg) >> # endif >> #endif >> >> >> >> This leaves ATTR_DEPRECATED undefined if the compiler doesn't support >> the __has_cpp_attribute macro, is that intended? Unless the idea is >> that some other method would be used to decide if it's available, it >> should be something like: >> >> #ifdef __has_cpp_attribute >> # if __has_cpp_attribute(deprecated) >> # define ATTR_DEPRECATED(msg) [[deprecated(msg)]] >> # endif >> #endif >> #ifndef ATTR_DEPRECATED(msg) >> # define ATTR_DEPRECATED(msg) >> #endif > > I think your modifications would be reasonable, though there are other > methods to decide if it's available (such as checking compiler > macros).
Indeed, and I wondered if that's the intention. My version would still allow that, by adding an #else branch to the #ifdef. I don't know if SD-6 (which is all about portable ways to detect such things) wants to show/suggest/encourage that though :-) _______________________________________________ Features mailing list Features@isocpp.open-std.org http://www.open-std.org/mailman/listinfo/features
