CallBack function

Hello C++ Guru,
       I want to create an object that will accept function name in the
parameter so, later in the process the function can be invoked back.
For instance I have my main class form and class A.
What would be the best way to somehow tell class A to invoke the function in
Main class after class done with the process? I want to make this as generic
as possible so can be used by anybody.
I heard about function pointer, but this wouldn't work with builder.
Here is the snippet I was trying to do, but didn't work
How do I passed the handle to the function parameter and How do I invoke
it?? what would be the best way to achive what I am trying to achive??

class cFieldVerify
    void Initialize(String TaskName, String KeyerSSN,
bool(*CallBackFunction))());     file://FUNCTION POINTER
    bool Execute();
    int GetIndex();
    bool IsUserVerifySelected();
    bool IsFieldVerified();
    void HideVerifyField();
    void __fastcall OnKeyDown(TObject *Sender, WORD &Key,TShiftState Shift);

    int mFieldCount;
    int mErrTryCount;
    String mTaskName;
    String mKeyerSSN;
    bool mIsVerified;
    int mVerifyFieldIndex[MAXFIELDCOUNT];
    DEdit *mFieldVerify;
    DEdit *mArrayField[MAXFIELDCOUNT];
    void ShowVerifyField();