Question

Is it possible to get the constituents of a member function such as class type or return type just from its address (not from member function type) ?

For e.g. given

 class foo
 {
    int bar()
    {
        return 5;
    }
 };

i like to have

is_same< function_types<&foo::bar>::class_type, foo>::value == true; 

I also know additionally that the member function has a signature like R (C::*)() i.e no arguments and no cv-qualification.

Thank you.

Answer 1

In C++ pre-0x, you can’t do this very easily. In C++0x, you can use a combination of template functions and decltype to do this:

template <typename R> struct unary_function_info { typedef R result_type; typedef void class_type; };
template <typename R> unary_function_info get_function_info(R (*)());

template <typename C, typename R> struct unary_member_function_info { typedef R result_type; typedef C class_type; };
template <typename C, typename R> unary_member_function_info get_function_info(R (C::*)());

is_same<decltype(get_function_info(&foo::bar))::class_type, foo>::value == true;

And then expand the above out for as high an arity as you need.