Forward declaration of nested types/classes in C++

Question

I recently got stuck in a situation like this:

class A
{
public:
    typedef struct/class {...} B;
...
    C::D *someField;
}

class C
{
public:
    typedef          


        

Answer 1

If you really want to avoid #including the nasty header file in your header file, you could do this:

hpp file:

class MyClass
{
public:
    template
    void doesStuff();
};

cpp file

#include "MyClass.hpp"
#include "Annoying-3rd-party.hpp"

template<> void MyClass::doesStuff()
{
    // ...
}

But then:

1. you will have to specify the embedded type at call time (especially if your function does not take any parameters of the embedded type)
2. your function can not be virtual (because it is a template)

So, yeah, tradeoffs...