Extending XFixes Extension

mcnichol at austin.ibm.com mcnichol at austin.ibm.com
Thu Nov 4 13:00:45 PST 2004

> From: Roland Mainz <roland.mainz at nrubsig.org>
> Keith Packard wrote:
> > > The current Xserver does not give client the ability to query the server to
> > > ask it which window belongs to (to client).
> > 
> > While the specification doesn't guarantee the partitioning of the resource
> > ID space is the same for every client, the implementation happens to work
> > that way.  So, identifying windows belonging to the same client is as
> > simple as masking their IDs with the resource mask in the Display
> > structure.
> This will only work with Xservers based on the X.org/Xfree86 codebase.
> Remember that there are other Xservers with a completely different
> codebase (for example: Weired/WiredX, which are written in JAVA or some
> of the MS-Windows Xserver products) which do not work that way.

The X server is not responsible for assigning resource IDs other that providing
a "connection id" that Keith alluded to above.  The resource IDs are assigned
by libX11.  And though it has been a while since I last dug through the Xlib spec,
I seem to remember that this is clearly documented.

> > Formalizing that in the XFixes documentation would be reasonable (i.e., an
> > X server advertising a specific XFIXES version would guarantee that the
> > resource ID partitioning was the same for all clients).


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