[Xcb] client message event strangeness

Thomas Hunger hto at arcor.de
Wed Apr 11 05:43:45 PDT 2007

> Another question about events. If an extension has an event (like
> damage, for example), is that 7th bit also set for the first_event
> member of the reply structure ?
Hi Vincent,

I am not quite sure if I understood you right, so maybe this is way 

the 7th (counting from 0) bit is only set, when the event was sent 
using SendEvent. As I understand it, "first_event" describes the 
offset of all the events in the extension. Extensions start to count 
their own events from 0, which would collide with the xproto event 0. 
Therefore an offset is needed (e.g. 35).

"first_event" is remembered on server side whenever an extension is 
added. Since the initialization of extensions is not ordered (or some 
may be missing), the value of first_event may change with each X 

The user needs to have a variable, e.g. "SelectionNotify_Event" from 
xfixes which has the local nr 0, add first_event and use this for 

case SelectionNotify_Event: [...]


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