...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::channel_severity_filter
// In header: <boost/log/expressions/predicates/channel_severity_filter.hpp> template<typename ChannelT, typename SeverityT> channel_severity_filter_actor< ChannelT, SeverityT > channel_severity_filter(attribute_name const & channel_name, attribute_name const & severity_name);