A question about C++ interop

[YD]

Hi, I have a C++ header file which looks like

     class A {
     public:
         static A *create();
         virtual int f() const = 0;
     };

And there is a C++ library file which provides the 
implementation, so that if I write a C++ program and call

     auto *p = A::create();
     std::cout << p->f() << '\n';

It will work.

Now I want to interface to this C++ library through D, and I wrote

     module test;

     import std.stdio;

     extern(C++) {
         class A {
                 static A *create();
                 abstract int f() const;
         }
     }

     void main() {
         auto p = A.create();
         writeln(p.f());
     }

This program will compile and link, but it core dumps at the call 
to f().

If I wrap up the C++ interface into a C interface (using a void 
*), and interface to the wrapped-up C library through D, it will 
work fine.

So what am I doing wrong here? Thanks!