An adapter class that allows a non_const member function that takes no arguments to be called as a unary function object when initialized with a pointer argument. Deprecated in C++11, removed in C++17.

template <class Result, class Type>
class mem_fun_t : public unary_function<Type *, Result> {
    explicit mem_fun_t(Result (Type::* _Pm)());

    Result operator()(Type* _Pleft) const;
};

_Pm
A pointer to the member function of class Type to be converted to a function object.

_Pleft
The object that the _Pm member function is called on.

An adaptable unary function.

The class template stores a copy of _Pm, which must be a pointer to a member function of class Type, in a private member object. It defines its member function operator() as returning (_Pleft->* _Pm)().

The constructor of mem_fun_t is not usually used directly; the helper function mem_fun is used to adapt member functions. See mem_fun for an example of how to use member function adaptors.