#include <iostream>
using namespace std;

class empty
{};

    template <class Base, int c=1>
    struct add_chars : Base {
        char dummy[c];
    };

    template <class T>
    struct has_trailing_unused_space {
        static const bool result = sizeof (add_chars<T>) == sizeof (T);
    };

    int main() {
        std::cout << "empty has trailing space: ";
        std::cout << has_trailing_unused_space<empty>::result;
    }