[cfe-dev] How to determine base class direct or not?

[r4start]

Hi all!

Can anybody help me with following problem. I have such code:
class B {
public:
   virtual void b(){}
   double b_field;
};

struct D : B {
   virtual void fr(){}
};

class C {
public:
   virtual void C_f(){}
};

class A : public C,
           public virtual D {
public:
   int a_field;
   virtual void a(){}
};
class A1 : public C, public B,
           public virtual D {
public:
   int a_field;
   virtual void a(){}
};

I write function that determines "Has class and his bases a common base?".
For example for class A this function returns false and for class A1 - 
true. In A1 as you can see B is base class for A1 and for D.
I tried to use isDerivedFrom(), but this function searches path from A 
to B(path is A->D->B) and if path exists return true.
I need something like isDirectDerivedFrom.

So my question is, what is the best way to determine these relations?

  - Dmitry.