The following code example is taken from the book
C++ Templates - The Complete Guide, 2nd Edition
by David Vandevoorde, Nicolai M. Josuttis, and Douglas Gregor,
Addison-Wesley, 2017
© Copyright David Vandevoorde, Nicolai M. Josuttis, Douglas Gregor 2017
template<typename T>
struct IsPointerToMemberT : std::false_type { // by default no pointer-to-member
};
template<typename T, typename C>
struct IsPointerToMemberT<T C::*> : std::true_type { // partial specialization
using MemberT = T;
using ClassT = C;
};