operator!=

template<class Ty>
    bool operator!=(const allocator<Ty>& left,
        const allocator<Ty>& right) throw();
template<class Ty1, class Ty2>
    bool operator!=(const shared_ptr<Ty1>& left,
        const shared_ptr<Ty2>& right);

The first template operator returns false. (All default allocators are equal.) The second template operator returns !(left == right).