...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
boost::movelib::operator!=
// In header: <boost/move/unique_ptr.hpp> template<typename T1, typename D1, typename T2, typename D2> bool operator!=(const unique_ptr< T1, D1 > & x, const unique_ptr< T2, D2 > & y);