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 IsPointerT : std::false_type { // primary template: by default not a pointer
};
template<typename T>
struct IsPointerT<T*> : std::true_type { // partial specialization for pointers
using BaseT = T; // type pointing to
};