...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
Forwarding function call operator.
template< typename... Args> result_of_t< T(Args...)> operator()( Args &&... args); » more... template< typename... Args> result_of_t< T(Args...)> operator()( Args &&... args) const; » more...