判断 Enum 里的QFlags 属性，不知道行不行。

enum SomeEnum { Value1, Value2, Value3 };
Q_DECLARE_OPERATORS_FOR_FLAGS( QFlags <SomeEnum>)
// The previous line declares
// Q_DECL_CONSTEXPR QFlags<SomeValue> operator|(SomeValue,SomeValue) {...}

int someFunction( QFlags <SomeEnum> value) {
    switch (value) {
        case SomeEnum::Value1:
            return 1 ;
        case SomeEnum::Value2:
            return 2 ;
        case SomeEnum::Value1 | SomeEnum::Value3:
        // Only possible with C++11 and because QFlags operators are constexpr
        // Previously this line would call
        //        QFlags<SomeValue> operator|(SomeValue,SomeValue)
        // that would have thrown an error because only compiler constants
        // are allowed as case satement

            return 3 ;
        default :
            return 0 ;
    }
}