class B {                   // Base class
protected:
    void (B::*fptest)();    // Function pointer to member function
public:
    void mtest()            // Class specific mebmer function
    { cout << "Base testn"; }
    void itest()            // Polymorphic function
    { (this->*fptest)(); }        // implemented by calling the poitner to member function
    B() : fptest(&B::mtest) { }   // Ctor must initialize the function pointer
    virtual ~B() {}
};

class D : public B {         // Derived class
public:
    void mtest()             // Class specific mebmer function
    { cout << "Derived testn"; }
    D()                     // Ctor
    { fptest = reinterpret_cast<void(B::*)()>(&D::mtest); }  // not sure it's this safe in case of multiple inheritance !!
};

B b;
D d;
B *pb = &b, *pd = &d;
pb->itest();
pd->itest();

; 41   :    pd->itest();  // cod for the call for a derived object
    mov ecx, DWORD PTR _pd$[ebp]        ; load the oject address
    call    ?itest@B@@QAEXXZ            ; call B::itest
; 16   :    void itest() { (this->*fptest)(); }
    push    ebp
    mov ebp, esp
    sub esp, 68                 ; 00000044H
    push    ebx
    push    esi
    push    edi
    mov DWORD PTR _this$[ebp], ecx   ; use address of object as parameter
    mov eax, DWORD PTR _this$[ebp]   ; load the function pointer
    mov ecx, DWORD PTR _this$[ebp]   ;  "    "
    mov edx, DWORD PTR [eax+4]       ; call the function pointer
    call    edx
    pop edi
    pop esi
    pop ebx
    mov esp, ebp
    pop ebp
    ret 0

39   :     pd->test();
    mov eax, DWORD PTR _pd$[ebp]
    mov edx, DWORD PTR [eax]
    mov ecx, DWORD PTR _pd$[ebp]
    mov eax, DWORD PTR [edx]
    call    eax