[Xcb] Qlength like in xcb

[Michele Comignano]

Hi,
i'm coding a simple compositing manager and i really miss something like the 
Xlib QLength. This macro returns the length of the event queue. It is really 
useful in a compositing manager to collect damaged areas and redraw them only 
at the end.
I cannot find a way to implement it through xcb, since the intersted 
structures are opaque.
Maybe I miss something, but a solution could be a xcb_poll_event like function 
than returns XCB_NONE in case of empty queue.

With regards :)

-- 
Michele Comignano (comick)
Jabber: comick at autistici.org
Web: http://comick.playlinux.net