...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::format_named_scope
// In header: <boost/log/expressions/formatters/named_scope.hpp> template<typename T, typename FallbackPolicyT, typename TagT, template< typename > class ActorT, typename CharT> format_named_scope_actor< FallbackPolicyT, CharT, ActorT > format_named_scope(attribute_actor< T, FallbackPolicyT, TagT, ActorT > const & placeholder, std::basic_string< CharT > const & element_format);