[Xcb] Window closed event and xcb_connect return value.

[shuLhan]

quick question,

1. how to get window-closed event ?

2. how do i check fail in xcb_connect() ?

	when i check in xcb_util.c, xcb_connect return
	(xcb_connection_t *) 1 if error. since xcb_connection_t is
	(struct) opaque type how do i cast this to integer ?