boost::log::expressions::is_in_range
// In header: <boost/log/expressions/predicates/is_in_range.hpp> template<typename T, typename FallbackPolicyT, typename TagT, template< typename > class ActorT, typename BoundaryT> unspecified is_in_range(attribute_actor< T, FallbackPolicyT, TagT, ActorT > const & attr, BoundaryT const & least, BoundaryT const & most);