Hi Anthony, Some minor implementation details: Why there is not other.future reset in shared_future(shared_future && other) { future.swap(other.future); } shared_future(unique_future<R> && other) { future.swap(other.future); } How the move is made? Is future.swap(other.future); other.future.reset(); more efficient than future.reset(other.future); other.future.reset(); ? Otherwise you can change it in: shared_future& operator=(shared_future && other) { future.swap(other.future); other.future.reset(); return *this; } shared_future& operator=(boost::detail::thread_move_t<shared_future> other) { future.swap(other->future); other->future.reset(); return *this; } shared_future& operator=(boost::detail::thread_move_t<unique_future<R> > other) { future.swap(other->future); other->future.reset(); return *this; } And once shared_ptr implements movable you could use future = move(other.future); Isn't it? Vicente