How to use call backs in C++ like delegates in C#?

Question

Possible Duplicate: What is a C++ delegate?

I need to use a callback in C++ like delegates in C#. For example, in C# we have:

...
      public delegate void SomeWorkhandeler(object Arg);
...
class A
{
    private SomeWorkhandeler doWork= null;
    public SomeWorkhandeler DoWork { get { return doWork; } set { doWork= value; } }
}

Now, what is the C++ code similar to this example?