...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::matches_fun::match_traits — A traits to obtain the tag of the expression.
// In header: <boost/log/utility/functional/matches.hpp> // A traits to obtain the tag of the expression. template<typename ExpressionT> struct match_traits { // types typedef unspecified tag_type; };