Struct template is

Struct template is_signed

boost::random::traits::is_signed — Traits class that indicates whether type T is a signed integer.

Synopsis

// In header: <boost/random/traits.hpp>

template<typename T> 
struct is_signed : public mpl::bool_< boost::is_signed< T >::value||(std::numeric_limits< T >::is_specialized &&std::numeric_limits< T >::is_integer &&std::numeric_limits< T >::is_signed)>
{
};