Re: [boost] [type_traits] warning free is_signed on g++

When using boost::is_signed<> on types such as unsigned int and unsigned long, various recent versions of g++ (MinGW 4.4.0 and Apple's 4.0.1, at least) spit out a warning:

warning: comparison of unsigned expression < 0 is always false

Would there be any harm in changing boost::detail::is_signed_helper in boost/type_traits/is_signed.hpp as follows?

template <class T> struct is_signed_helper { typedef typename remove_cv<T>::type no_cv_t; // BOOST_STATIC_CONSTANT(bool, value = (static_cast<no_cv_t>(-1) < 0)); BOOST_STATIC_CONSTANT(bool, value = (static_cast<no_cv_t>(-1) < 1)); };

This change gets rid of the warnings emitted by g++.

Already been there and fixed it: https://svn.boost.org/trac/boost/ticket/3381 John.