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
#include <iostream>
template<typename T>
void tmplParamIsReference(T) {
std::cout << "T is reference: " << std::is_reference_v<T> << '\n';
}
int main()
{
std::cout << std::boolalpha;
int i;
int& r = i;
tmplParamIsReference(i); // false
tmplParamIsReference(r); // false
tmplParamIsReference<int&>(i); // true
tmplParamIsReference<int&>(r); // true
}