Jan Vroonhof <vroonhof(a)math.ethz.ch&gt; writes in xemacs-beta(a)xemacs.org: The Doug Lea or "new GNU malloc" is the system malloc when using glibc or Linux libc5; it has not been cloned into the XEmacs core. The so-called "new GNU malloc" in XEmacs is really the old GNU malloc, and the "old GNU malloc" in XEmacs is really the very-old GNU malloc. All Doug Lea malloc related stuff is guarded by ifdefs and are only enabled if configure detects the presence of it. It should be absolutely safe to apply the patch and it is better than voodoo_free_hook. -- I protest the NATO war in Yugoslavia.