int pascal GetScrollRange(HWND hBar, int nBar, int *minpos, int *maxpos)

  This function retrieves the minimum and maximum values of a
scrollbar's scrolling range. When a scrollbar is first created, it is
given the default scroll range of 0 to 100.

Parameters
  hBar is the handle to the scrollbar.
  nBar indicates which scrollbar you want to operate on. If nBar is
   SB_CTL, then the hBar parameter contains the handle of the actual
   scrollbar you want to manipulate. If nBar is SB_HORZ, then you want
   to manipulate the horizontal scrollbar which belongs to window hBar.
   If nBar is SB_VERT, then you want to manipulate the vertical
   scrollbar which belongs to window hBar.
  minpos and maxpos are pointers to integer variables which will be
   used to store the minimum and maximum positions respectively.

Returns
  Nothing.