How to declare my TList->sort function in (Class)header?

I'm using Borland C++ Builder and I've written my own sort function to sort a TList.

The code is:

int __fastcall my_sort_function(void *Item1, void *Item2){

      ... compare something
      return(result);
}

Im using it to do: MySortList->Sort(my_sort_function);

That works well!

The Question is:
How to declare
int __fastcall my_sort_function(void *Item1, void *Item2)
in the header file to make it a class member?

Reason: I'd like to give "my_sort_function" access to some class members.

This may be a stupid question? But I'm very new to C++ and learn the basic concepts now. Can anyone help me?


Thanks in advance!