[plt-scheme] DrScheme/MrEd crash on x86_64

From: Matthew Flatt (mflatt at cs.utah.edu)
Date: Thu Apr 14 12:38:03 EDT 2005

At Sat, 09 Apr 2005 19:34:26 -0400, Anton van Straaten wrote:
> The error occurs when attempting to select text anywhere in DrScheme, or 
> even in the MrEd REPL.  Selection of text appears to occur normally, 
> whether the shift key or the left mouse button is used, but as soon as 
> the shift key or mouse button is released, the error occurs and 
> MrEd/DrScheme dies.

That's a very helpful clue.

This might be fixed in CVS. There's a good chance of success if the

 #include <stdio.h>
 #include <X11/X.h>

 int main()
   printf("%d\n", sizeof(Atom));
   return 0;

prints 8 instead of 4.

> [...] setting a breakpoint on _XError 
> allowed a stack trace to be obtained when the error occurs, which I've 
> attached.  It looks pretty generic, though, so the offending code wasn't 
> obvious to me.

If I'm on the right track, then it helped, especially in combination
with your clue.

If selection works, then I wonder whether opening a file works, too (as
in the original report). I'm not sure they're the same bug.


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