<queue>

namespace std {
template<class T, class Cont>
    class queue;
template<class T, class Cont, class Pred>
    class priority_queue;
//    TEMPLATE FUNCTIONS
template<class T, class Cont>
    bool operator==(const queue<T, Cont>& lhs,
        const queue<T, Cont>&);
template<class T, class Cont>
    bool operator!=(const queue<T, Cont>& lhs,
        const queue<T, Cont>&);
template<class T, class Cont>
    bool operator<(const queue<T, Cont>& lhs,
        const queue<T, Cont>&);
template<class T, class Cont>
    bool operator>(const queue<T, Cont>& lhs,
        const queue<T, Cont>&);
template<class T, class Cont>
    bool operator<=(const queue<T, Cont>& lhs,
        const queue<T, Cont>&);
template<class T, class Cont>
    bool operator>=(const queue<T, Cont>& lhs,
        const queue<T, Cont>&);
    };

Include the STL standard header <queue> to define the template classes priority_queue and queue, and two supporting templates.