Ladies and gentle men, I bring to you, the Binteger (bool + int).

#define NET_ERR_UNEXPECTED_SUCCESS                      DEF_ERROR(NET_ERR_BASE + 3)

Actual (sanitized) quote from actual game source I've worked on:

#define NET_ERR_UNEXPECTED_SUCCESS                      DEF_ERROR(NET_ERR_BASE + 3)

Unexpected success, aye? To me, that sounds like an issue that only Guild Wars 2 would encounter

But does it support FILE_NOT_FOUND?

I believe boosts tribool still does this wrong as well, by not defining the third states value.

washu wrote me this :)

struct beufint_t {
public:
    beufint_t () : t(et::n), u(0) {}
    beufint_t (bool b) : t(et::b), b(b) {}
    beufint_t (float f) : t(et::f), f(f) {}
    beufint_t (int i) : t(et::i), i(i) {}
    beufint_t (unsigned u) : t(et::u), u(u) {}
    
    operator bool () const { return t == et::b ? b : false; }
    operator int () const { return t == et::i ? i : 0; }
    operator float () const { return t == et::f ? f : 0; }
    operator unsigned () const { return t == et::u ? u : 0; }
    operator void const * () const { return t != et::n ? this : 0; }

    bool operator () (bool) const { return t == et::b; }
    bool operator () (int) const { return t == et::i; }
    bool operator () (float) const { return t == et::f; }
    bool operator () (unsigned) const { return t == et::u; }
private:
    enum class et {
        b,
        f,
        i,
        u,
        n
    };
    
    union {
        bool b;
        float f;
        int i;
        unsigned u;
    };
    
    et t;
};