Explicit ID

explicit_id.cpp

template <typename T, typename UniqueTag>
class ExplicitArithmeticID
{
public:
	static_assert(std::is_arithmetic<T>::value, "ExplicitArithmeticID is for arithmetic types only");
	using UnderlyingType = T;

	constexpr explicit ExplicitArithmeticID(T value) : mUnderlyingValue(value) {};
	
	const T& underlying() const
	{
		return mUnderlyingValue;
	}

private:
	T mUnderlyingValue;
};

struct GeoIDTag {};
using GeoID = ExplicitArithmeticID<int, GeoIDTag>;
struct TerIDTag {};
using TerID = ExplicitArithmeticID<int, TerIDTag>;

void foo(GeoID) {}

int main()
{
	foo(GeoID(0));
	// foo(TerID(0)); // compilation error

	system("pause");
	return 0;
}