This shows how to enable a template for an explicit list of types.

enable_for.cpp

#include <iostream>
#include <type_traits>

template<typename T, typename... UsableTypes>
struct SearchImpl : std::is_same<T, UsableTypes>...
{
};

template<typename T, typename... UsableTypes>
struct Search : std::is_base_of<std::true_type, SearchImpl<T, UsableTypes...>>::type 
{
};

// Enable a given template only for a given list of types.
// Works assuming all the types given are unique
template<typename T, typename... UsableTypes>
struct enable_for : std::enable_if<Search<T, UsableTypes...>::value, int>
{
};

// Example:

template<typename T, typename enable_for<T, char, short, int, long, long long>::type = 0>
void print_classification(T) {
std::cout << "This is an integral type" << std::endl;
}

template<typename T, typename enable_for<T, double, float>::type = 0>
void print_classification(T) {
std::cout << "This is a floating point type" << std::endl;
}

template<typename T, typename enable_for<T, double, float>::type = 0,
         typename U, typename enable_for<U, char, short, int, long, long long>::type = 0>
void print_classification(T, U) {
std::cout << "float then int" << std::endl;
}

template<typename T, typename enable_for<T, char, short, int, long, long long>::type = 0,
         typename U, typename enable_for<U, double, float>::type = 0>
void print_classification(T, U) {
std::cout << "int then float" << std::endl;
}

template<typename T, typename enable_for<T, char, short, int, long, long long>::type = 0,
         typename U, typename enable_for<U, char, short, int, long, long long>::type = 0>
void print_classification(T, U) {
std::cout << "both int" << std::endl;
}

template<typename T, typename enable_for<T, double, float>::type = 0,
         typename U, typename enable_for<U, double, float>::type = 0>
void print_classification(T, U) {
std::cout << "both float" << std::endl;
}

int main() {
std::cout << Search<int, double, int>::value << std::endl;
print_classification('a');
print_classification((short)2);
print_classification(2);
print_classification(2l);
print_classification(2ll);
print_classification(2.);
print_classification(2.0f);
print_classification(2., 3);
print_classification(3, 2.);
print_classification(2, 2);
print_classification(2., 2.);
int a = 2;
int &b = a;
int &&c = 2;
print_classification(a);
print_classification(b);
print_classification(c);
return 0;}