...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::log::operator<=
// In header: <boost/log/utility/value_ref.hpp> template<typename U, typename T, typename TagT> bool operator<=(U const & left, value_ref< T, TagT > const & right);