A question about C++ interop

[YD via Digitalmars-d-learn]

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!