dummy (or not) question about AllocateWindow ()

Wed Jun 21 10:52:31 PDT 2006

Hi,
In AllocateWindow () from dix/window.c what this line does:
ppriv = (DevUnion *)(pWin + 1);
It's after the first *if* of the function.
I can't realize this operation. This appear to cast the XID (the 4th
byte) in DrawableRec (the first struct in _Window) to a DevUnion and
then make the devPrivate point to the same place.
Can anybody explaim this?
Thanks,
-- 
Carlos Eduardo Rodrigues Diógenes
Projeto xLupa - http://www.unioeste.br/projetos/xlupa