Nelson, Clark wrote: > Technically, at the moment we are exploring __has_cpp_attribute as a > direction. It hasn't yet been approved by WG21.
Ok > > The rationale for not recommending __has_feature is hinted at in the > document: > > [3] Fortunately Clang has ways to test specifically for the presence of > specific features. But unfortunately, the function-call-like syntax used > for such tests won't work with a standard preprocessor, so this fine new > feature winds up adding its own flavor of complexity to the mix. Thanks for pointing that out. Unfortunately I do not know what does or does not make a 'standard preprocessor', so I don't understand. What is the difference, in that sense, between __has_include and __has_feature? > To put it more bluntly, SG10's purpose is to make it possible for a > program to detect what new features are present in an implementation. If > we had made a recommendation that depended entirely on the existence of > yet another new feature, we would have built a castle in the air. I don't understand this either I'm afraid :(. Are you suggesting that something similar to the __has_include example in the document can not work or is fundamentally undesirable? #ifdef __has_feature # if __has_feature(cpp_variadic_templates) # define BOOST_HAVE_VARIADIC_TEMPLATES # endif #endif Thanks, Steve. _______________________________________________ Features mailing list [email protected] http://www.open-std.org/mailman/listinfo/features
