Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!cs.utexas.edu!swrinde!ucsd!ucbvax!bloom-beacon!LARRY.MCRCIM.MCGILL.EDU!mouse
From: mouse@LARRY.MCRCIM.MCGILL.EDU
Newsgroups: comp.windows.x
Subject: Re:  problem on XOpenDisplay()
Message-ID: <9012071025.AA17351@Larry.McRCIM.McGill.EDU>
Date: 7 Dec 90 10:25:11 GMT
Sender: daemon@athena.mit.edu (Mr Background)
Organization: The Internet
Lines: 25

> I have programmed multi-user talk program.  I use motif and X window
> system for my environment.  I use XOpenDisplay() function to open
> other display.  It work well if someone use the display already.  But
> when I test to open the display nobody use, I found that it does not
> return NULL for showing fail and it stop to work.

Normally, if no server is running, it will return 0 right away.  If the
machine is unreachable, it will time out and return 0.  If neither of
these is happening, I would guess that your displays are under the
control of xdm.  When xdm has its login window up, I believe the server
is normally grabbed.  When a client tries to connect, the connection
will typically succeed immediately (because the server's
connection-accepting socket is still listening for connections) but the
server will pay no attention to the new connection until someone logs
in and the server is ungrabbed.

I don't see any real solution to your problem as stated.  Everything in
the above description is functioning the way it's intended to.  About
all I can say is to ask why you're trying to XOpenDisplay on a display
without even knowing whether anyone's on it or not....

					der Mouse

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			new: mouse@larry.mcrcim.mcgill.edu