Adrian Aichner <aichner(a)ecf.teradyne.com&gt; writes: interesting. You got lucky. The GC collected function in function_argcount but the pointer still pointed to a valid LispObject (the list in the backtrace). I assume this is _not_ a debug build? In debug builds we try to make sure that collected objects are really invalid, to get a crash early on. I had fixed this by adding a GCPRO (see xemacs-patches) yesterday but didn't get around to mailing the patch. thanks for testing. Gunnar.