An adapter class that allows a const member function that takes a single argument to be called as a binary function object when initialized with a reference argument. Deprecated in C++11, removed in C++17.

template <class Result, class Type, class Arg>
    class const_mem_fun1_ref_t
        : public binary_function<Type, Arg, Result>
{
    explicit const_mem_fun1_ref_t(Result (Type::* Pm)(Arg) const);
    Result operator()(const Type& left, Arg right) const;
};

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

left
The const object that the Pm member function is called on.

right
The argument that is being given to Pm.

An adaptable binary 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 (left.* Pm)(right) const.

The constructor of const_mem_fun1_ref_t is not usually used directly; the helper function mem_fun_ref is used to adapt member functions. See mem_fun_ref for examples of how to use member function adaptors.