On 14 June 2018 at 19:51, Jonathan Wakely <jwak...@redhat.com> wrote: > On 14/06/18 10:46 -0600, Martin Sebor wrote: >> >> On 06/13/2018 10:30 AM, Jonathan Wakely wrote: >>> >>> The C++ committee has confirmed that passing a null pointer to the >>> unary basic_string_view constructor is undefined. This removes the check >>> from our implementation, and adds the nonnull attribute to warn when the >>> compiler can detect undefined input. >>> >>> Any objections to this change? >> >> >> I have a general question about using the new C++ attributes in >> libstdc++ (standard or otherwise): what does C++ have to say about >> programs that define macros with the same names? E.g., is this >> a valid program? >> >> #define nonnull "..." >> ... >> #include <string_view> >> >> How about: >> >> #define noreturn "..." >> ... >> #include <string_view> >> >> The view in WG14 is that the corresponding C programs (if C2X >> were to adopt the proposed C++ attributes) would be valid and >> that it's up to implementations to make it work. > > > Good point, I suppose I have to use __attribute__((__nonnull__)) > instead. The reason I didn't is that I find the grammar for the > position of C++11 attributes much easier to understand. But in this > instance the same location works for either.
[macro.names]/2 forbids #defining macros with the same names as the standard attributes. The programs Martin shows as examples are not valid.
