+inline State operator|(State a, State b)
+{ return static_cast<State>(static_cast<int>(a)|static_cast<int>(b)); }
+
+inline State operator|=(State &a, State b)
+{ a = a|b; return a; }
+
+inline State operator&(State a, State b)
+{ return static_cast<State>(static_cast<int>(a)&static_cast<int>(b)); }
+
+inline State operator&=(State &a, State b)
+{ a = a&b; return a; }
+
+inline State operator~(State a)
+{ return static_cast<State>(~static_cast<int>(a)); }
+
+MSPGLTK_API std::istream &operator>>(std::istream &, State &);