 <B>Tk_Screen</B> returns a pointer to
the Xlib structure corresponding to <I>tkwin</I>'s screen.
<P>
<B>Tk_X</B>, <B>Tk_Y</B>, <B>Tk_Width</B>, and <B>Tk_Height</B>
return information about <I>tkwin's</I> location within its
parent and its size.  The location information refers to the
upper-left pixel in the window, or its border if there is one.
The width and height information refers to the interior size
of the window, not including any border.  <B>Tk_Changes</B>
returns a pointer to a structure containi