有什么方法可以在不引用其模板类型的情况下向前声明指向类的指针？

Question

In foo.h:

#include <vector>
class A {
    int x;
};
typedef std::vector<A> AVector;

What I want is to put this in bar.h:

#include <vector>
<<< some forward declaration of AVector here>>>;

class B {
    AVector *myVector;
};

I would like to forward declare "AVector" into bar.h without bar.h having to include the definition of class A. Since class B only needs to know it is a pointer and not the details inside the pointer, I was hoping there was some way to declare this.

Note: I am aware that I could just declare "void *" and then cast at various points. I would rather not lose the type safety. Any solution that does lose the type safety isn't going to solve my problem.

Answer 1

From Jean-BaptisteYunès comment on the question, you can forward declare a std::vector without the full definition of A. That means this works:

class A;
typedef std::vector<A> AVector;
class B {
    AVector *myVector;
};