...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 T1, typename TagT1, typename T2, typename TagT2> bool operator<=(value_ref< T1, TagT1 > const & left, value_ref< T2, TagT2 > const & right);