Re: [boost] OK to remove Concept related config macros?

Subject: Re: [boost] OK to remove Concept related config macros?
From: Doug Gregor (doug.gregor_at_[hidden])
Date: 2011-03-16 16:44:19

On Wed, Mar 16, 2011 at 11:33 AM, John Maddock <boost.regex_at_[hidden]> wrote:
>> /home/hunold/src/devel/boost/boost/type_traits/common_type.hpp:70:22:
>> warning:
>> variadic templates only available with -std=c++0x or -std=gnu++0x
>> /home/hunold/src/devel/boost/boost/type_traits/common_type.hpp:150:46:
>> warning: variadic templates only available with -std=c++0x or -std=gnu++0x
>>
>> as soon as TypeTraits are used.
>> This ist gcc-4.5, gcc-4.4 and gcc-4.6 (Mingw)
>
> OK here's the lowdown:
>
> GCC *does* support a number of C++0x features in non-C++0x mode, including
> variadic templates... that's because these features are used within the std
> lib.... but... gcc emits copious warnings if you use these features without
> turning off all warnings from the header that uses them with #pragma
> system_header.  This also causes some of the type_traits tests to fail
> because they're run with warnings-as-errors.  Oh and there's no way to
> selectively turn these warnings off, or to selectively turn them into errors
> :-(

FWIW, Clang (2.9, top-of-tree) does the same thing, but there you can
use -Werror=c++0x-extensions .

  - Doug