ChangeProc( <hWnd> ) -> <nOldProc>
------------------------------------------------------------------------------


 PARAMETER:

  <hWnd>        Is the handle of the target window


 RETURNS:

  <nOldProc>    this is a LONG Pointer with the adress of the former window 
                procedure 
                 

 DESCRIPTION:

  This function replaces the procedure that controls the behavior of a 
  function with a FiveWin function. This way we can intercept each 
  message to our window and redirect it to the different methods of our
  twindow class.

  This technique is quite common in windows and is called 'subclassing'.
  

 SOURCE:  

  SOURCE\WINAPI\CHANGEPR.C