Subject: [boost] [type_traits] warning free is_signed on g++
From: Edd Dawson (lists_at_[hidden])
Date: 2009-09-12 10:51:51
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>
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++.