How to perform casting with multiple inheritance

Question

My classes structure is like:

class MethodHelper : public QObject, public IMethodHelper {
public:
    // Stuff
};

Now, I get a pointer to the object:

QObject* someObject = getMethodHelper();

Here, I am extremely sure that someObject is a type of MethodHelper. I somehow want to cast it to IMethodHelper. How should I go about it?

My current thoughts are like QObject -> MethodHelper -> IMethodHelper, like:

QObject* someObject = getMethodHelper();
MethodHelper* myHelper = qobject_cast<MethodHelper*>(someObject);
IMethodHelper* myIHelper = dynamic_cast<IMethodHelper*>(myHelper);

is there a potential flaw in my approach?

Answer 1

You could do it the way you present, but it isn't necessary. The Below should work fine.

IMethodHelper* myIHelper = dynamic_cast<IMethodHelper*>(someObject);