On 14/06/18 19:54 +0300, Ville Voutilainen wrote:
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.
But nonnull isn't a standard attribute though. So we can't use
[[gnu::xxx]] attributes in libstdc++ and have to use __attribute__
instead.
[[sad_face]]
