J.Crowcroft@ucl-cs.UUCP (05/30/89)
From: Jon Crowcroft <J.Crowcroft@uk.ac.ucl.cs> I hope this is the right place for these comments - I have a lot of uses for programs that run on many displays - it would seem that some sort of discipline is required in making sure the various libs and applications do the right thing when keeping track of windows on multiple displays - one clue to problems is consideration of server state versus application versus window manager... 1. Seems to me that some bugs are to do with static's being used a little hairily: e.g. in ...lib/Xt/GCManager.c XtGetGC uses static Drawable GCparents[256]; /* static initialized to zero, K&R ss 4.9 */ but doesnt check whether the Drawable is on the same Display as cur-dpy, so XCreateGC fails on a second display under certain circumstances... 2. in ...lib/Xaw/Simple.c and Scroll.c the Realize routines rely on the Initialize routines or other code to have set up Pixmap's for Cursors for the class, rather than this realization of the class.... This fails on the second display again, because the lib has a reference to a GC that is only valid on the first Display. These would seem to be generic problems through the Intrinsics and Athena Widget set - are they addressed by R4??? The twm problem i have been having is related, and is to do with event Dispatching in an application on one machine being a client on many servers - The Enter and Leave notify handlers refer to a single Display (again a single global for twm) which causes confusion, since they call XSetInputFocus with this Display when the event came from another one...should use event.xany.display rather than single dpy... If i want to post my attempts at fixes - whats the right list? plus if i have a contrib application, where does that go to? (sorry if i'm bothering list, just we are a bit far away in the net here...) cheers jon
rws@EXPO.LCS.MIT.EDU (05/31/89)
These would seem to be generic problems through the Intrinsics and
Athena Widget set - are they addressed by R4???
I suspect most of the major multiple-display Intrinsics bugs are known about;
whether or not they'll be fixed in R4 is unknown at the present time. You are
encouraged to report any bugs you know about to xbugs, to make sure they aren't
missed. Multiple-display support for the Athena widgets is not currently a
priority, although we have done some basic groundwork to make the task easier.
Again, no commitments about R4 on this. Again, you are encouraged to submit
bug reports.