Here comes the real fix - we don't need to set __malloc_hook et al if we use DOUG_LEA_MALLOC. I do know now why setting __malloc_hook to NULL fails - but a fix might take a bit longer. The appended patch is IMO the right way to fix XEmacs. Andreas P.S. CC'ed to xemacs-patches - please remove it when replying. 1999-10-28 Andreas Jaeger <aj(a)suse.de&gt; * src/emacs.c (main_1): Don't set the malloc hooks if using DOUG_LEA_MALLOC. --- src/emacs.c.~2~ Thu Jun 17 08:31:05 1999 +++ src/emacs.c Thu Oct 28 16:43:07 1999 ＠＠ -531,7 +531,7 ＠＠ extern int malloc_cookie; #endif -#if !defined(SYSTEM_MALLOC) && !defined(HAVE_LIBMCHECK) +#if !defined(SYSTEM_MALLOC) && !defined(HAVE_LIBMCHECK) && !defined DOUG_LEA_MALLOC /* Make sure that any libraries we link against haven't installed a hook for a gmalloc of a potentially incompatible version. */ /* If we're using libmcheck, the hooks have already been initialized, */ -- Andreas Jaeger SuSE Labs aj(a)suse.de private aj(a)arthur.rhein-neckar.de