Hrvoje> Many of the recent performance changes included replacing Hrvoje> Fsetcar() and Fsetcdr() with XCAR/XCDR on the left side of Hrvoje> an assignment. [...] Hrvoje> (In fact, on *real* Unixes, we could simply use Hrvoje> sigaction() to trap SIGSEGV and have the handler check Hrvoje> whether the SEGV was caused by modifying a pure cons, and Hrvoje> signal an error in that case. Of course, this would not Hrvoje> work on Linux.) My Linux allegedly supports sigaction(), according to the man page. If the problem is SYSV semantics, that is supposed to be fixed by glibc as I understand it. In any case, if Linux is not a real Unix in this respect, so much the worse for Linux---special case it for Linux and let us Linux users worry about maintaining it. -- University of Tsukuba Tennodai 1-1-1 Tsukuba 305-8573 JAPAN Institute of Policy and Planning Sciences Tel/fax: +81 (298) 53-5091 __________________________________________________________________________ __________________________________________________________________________ What are those two straight lines for? "Free software rules."