How to know underlying type of class enum?

Question

I have a variable declared as:

enum class FooEnum: uint64_t {}

and I would like to cast to its base-type, but I don\'t want to hardcode the

Answer 1

Both Visual C++ 10.0 and MinGW g++ 4.6.1 lack std::underlying_type, but both accept this code:

template< class TpEnum >
struct UnderlyingType
{
    typedef typename conditional<
        TpEnum( -1 ) < TpEnum( 0 ),
        typename make_signed< TpEnum >::type,
        typename make_unsigned< TpEnum >::type
        >::type T;
};