How can I use an enum class in a boolean context?

Question

I have some generic code that works with flags specified using C++11 enum class types. At one step, I\'d like to know if any of the bits in the flag are set. Cu

Answer 1

struct Error {
    enum {
        None        = 0,
        Error1      = 1,
        Error2      = 2,
    } Value;

    /* implicit */ Error(decltype(Value) value) : Value(value) {}

    explicit operator bool() {
        return Value != Error::None;
    }
};

inline bool operator==(Error a, Error b) {
    return a.Value == b.Value;
}

inline bool operator!=(Error a, Error b) {
    return !(a == b);
}

enum has no overloaded operator for now, so wrap it in a class or struct.