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From: diamant@hpfclp.SDE.HP.COM (John Diamant)
Newsgroups: comp.windows.x
Subject: Re: Is a window manager running?
Message-ID: <9740074@hpfclp.SDE.HP.COM>
Date: 18 Nov 88 05:43:14 GMT
References: <3921@omepd>
Organization: HP SDE, Fort Collins, CO
Lines: 21

> Window managers typically select for SubstructureRedirect
> on the root window, and only one client can select for this.
> So you can use success/failure of selecting for this as a
> pretty reliable indicator.  The fact that not all window
> managers check for failure here is a bug.

Not all window managers do this though.  I haven't looked at R3 yet, so this
may no longer be true, but R2 uwm didn't.  It would be nice for at least some
window managers not to select for SubstructureRedirect that (I think that
is only required on a reparenting window manager) because this can be a
real performance bottleneck under some cirucumstances (a request has to go
from client to server, to window manager, back to server, and back
to client, at least for toolkit requests and such that need to know if their
request was granted).  This is much worse than a round trip -- it's two
cascaded round trips.


John Diamant
Software Engineering Systems Division
Hewlett-Packard Co.		ARPA Internet: diamant@hpfclp.sde.hp.com
Fort Collins, CO		UUCP:  {hplabs,hpfcla}!hpfclp!diamant