Forward declaration with boost::shared_ptr

Hey, I have a quick question.

How can I forward declare something when I use boost::shared_ptr?

Code:

---

// File A

class ClassA;
typedef boost::shared_ptr<ClassA> ClassA_ptr;

class A
{
        Do cool stuff
};


// File B

class ClassA;

class B
{
public:
        Do cool stuff

private:
        ClassA_ptr variableName // <-- How to forward declare this one?
};

---

Thanks :)

In theory, yes - but you have to explicitly define the destructor and make sure that ClassA is fully defined at that point.

In practice, I've seen this fail on some compilers.

Ok, so its safer and easier to just include the header then I guess.

This is the first time im using smart pointers, so just one more quick question. Is there any problems when it comes to inheritance?

EDIT: Never mind the last question. I was lazy and asked instead of checking it out myself. It looks like inheritance is no problem at all.
Thanks for answering the original question CornedBee

Although note that a shared_ptr<Derived> won't implicitly convert to shared_ptr<Base>. But you can use dynamic_pointer_cast to get around that.

Yes, it will. Or at least should. You should only need dynamic_pointer_cast to get from shared_ptr<Base> to shared_ptr<Derived>.

Funny. I could've sworn it didn't work before, but what do you know... it actually does work now.
Problem solved, then.