std::mem_fun_t, std::mem_fun1_t, std::const_mem_fun_t, std::const_mem_fun1_t

template< class S, class T > 
class mem_fun_t : public unary_function<T*,S> {
public:
    explicit mem_fun_t(S (T::*p)());
    S operator()(T* p) const;
};

template< class S, class T > 
class const_mem_fun_t : public unary_function<const T*,S> {
public:
    explicit const_mem_fun_t(S (T::*p)() const);
    S operator()(const T* p) const;
};

template< class S, class T, class Arg > 
class mem_fun1_t : public binary_function<T*,A,S> {
public:
    explicit mem_fun1_t(S (T::*p)(A));
    S operator()(T* p, A x) const;
};

template< class S, class T, class A > 
class const_mem_fun1_t : public binary_function<const T*,A,S> {
public:
    explicit const_mem_fun1_t(S (T::*p)(A) const);
    S operator()(const T* p, A x) const;
};