Holding CTRL+G pressed for a while, 10 seconds maybe, issues a fatal error.
 
Version: Version: 21.4.1-2   (On my debian SID disttribution)
 
Text straight from the console:
 
ISO8:T-----XEmacs: UserObject.h      (C)----L22--All------------------------------------------
 
[1]+  Stopped                 xemacs UserObject.h
pok@king:~/pok2/src/server/pokt/pokts$ fg
xemacs UserObject.h
Auto-save? (y or n) y
Fatal error: assertion failed, file eval.c, line 3963, !gc_in_progress
 
Fatal error (6).