class B { /* ... */ };

class A {
public:
    A() { obj = NULL; }
private:
    static B* obj;
};

However this produces huge mass of linker errors that symbol obj is unresolved.

What's the "correct" way to have such private static class member without these linker errors?

Edit: I tried this:

B *A::obj = NULL;

but I got about same amount of linker errors however this time about already defining A::obj. (LNK2005).

Also I get LNK4006 warnings, also about A::obj