Boost
  C++ Libraries
  
  ...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 T, typename D> bool operator>(const unique_ptr< T, D > & x, std::nullptr_t);