...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::proto::result_of::env_var —
Metafunction for computing the return type of proto::env_var()
.
// In header: <boost/proto/transform/env.hpp> template<typename Env, typename Key> struct env_var : boost::result_of<proto::functional::env_var<Key>(Env)> { };