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 IsEnumT {
static constexpr bool value = !IsFundaT<T>::value &&
!IsPointerT<T>::value &&
!IsReferenceT<T>::value &&
!IsArrayT<T>::value &&
!IsPointerToMemberT<T>::value &&
!IsFunctionT<T>::value &&
!IsClassT<T>::value;
};