...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::contains
// In header: <boost/log/expressions/predicates/contains.hpp> template<typename T, typename SubstringT> unspecified contains(attribute_name const & name, SubstringT const & substring);