...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_ATTRIBUTE_KEYWORD — The macro declares an attribute keyword.
// In header: <boost/log/expressions/keyword.hpp>
BOOST_LOG_ATTRIBUTE_KEYWORD(keyword_, name_, value_type_)