...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::expressions::has_attribute
// In header: <boost/log/expressions/predicates/has_attr.hpp> template<typename T> class has_attribute { public: // types typedef bool result_type; // Function result_type. typedef T value_type; // Expected attribute value type. // construct/copy/destruct explicit has_attribute(attribute_name const &); // public member functions template<typename ArgT> result_type operator()(ArgT const &) const; };