Pass __closure functions in constructor

Refer to this small top-of-my-head coed snippet:

typedef void __fastcall (__closure *GetHTTPCallBack)(String filename);

class Foo {

  private:

  public:
    GetHTTPCallBack Callback;

         __fastcall Foo         (void)                     { Callback = NULL;     }
         __fastcall Foo         (GetHTTPCallBack callback) { Callback = callback; }
};

class Bar {

  private:
    Foo *foo;

  public:
    void __fastcall CallbackFunction(String fileName) { // Do something  }
    void __fastcall SetByConstructor(void)            { foo = new Foo(CallbackFunction); }
    void __fastcall SetByAssignment (void)            { foo = new Foo(); foo->Callback = CallbackFunction; }
};

Bar bar;

Now to the problem.

If Call bar.SetByAssignment() it works fine, the function pointer is set and called correctly from Foo. But in this case it is exposed as a public variable. I would like it to be private.

I would like to simplify the class, and hide it to be private, by passing the function pointer in the constructor, bar.SetByConstructor() but here I get compiler error:

[bcc32 Error] : Member function must be called or its address taken

I thought the __closure would make this possible. Is it possible at all or I'm I just doing it wrong?

Do what the compiler tells you. Pass the memory address of the method. How do you get the memory address of anything? Use the & address operator:

foo = new Foo(&CallbackFunction); 

It is good habit to do that when using an assignment as well (though in that case it is optional):

foo->Callback = &CallbackFunction;