Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!mips!sgi!shinobu!fido.wpd.sgi.com!marktwain.rad.sgi.com!linton
From: linton@marktwain.rad.sgi.com (Mark Linton)
Newsgroups: comp.windows.interviews
Subject: Re: urgent delete world problem
Message-ID: <1991Jun5.234008.20856@fido.wpd.sgi.com>
Date: 5 Jun 91 23:40:08 GMT
References: <9106042350.AA15775@chipcom.CHIPCOM.COM>
Sender: news@fido.wpd.sgi.com (Usenet News Admin)
Reply-To: linton@marktwain.rad.sgi.com (Mark Linton)
Organization: sgi
Lines: 17

In article <9106042350.AA15775@chipcom.CHIPCOM.COM>, chipcom!cathryn@UUNET.UU.NET (Cathryn Szekely) writes:
|> I have a program that spawns a child process, and I am having trouble
|> dealing with deleting the World in the child process, then returning to 
|> the parent.
|> The error message displayed started with:
|>   X Error: BadIDChoice, invalid resource ID chosen for this connection....

The problem is the child gets a copy of the X Display information, which includes
things like the "next" resource id to allocate (for things like windows).  The parent
has the original.  The child uses the (shared) connection, using resource ids.
When the parent tries to allocate a resource id later, it tries one the child has already used.

|> X Error: Bad Font ...

In 2.6, we do font caching that does not work properly across multiple displays.
So, it looks up a font name in the child and tries to use it on the child's new display connection.
This is fixed in 3.0, but I don't know how easy it would be for you to convert.