A line like this in /etc/ttys:

ttyv1  	"/usr/libexec/getty Pc"		whatever on secure
(i.e. a line with a terminal type that's not in termcap)

combined with tcsh 6.04 and no terminal type setting in .cshrc
or .login used to give me:

free(1) below bottom of memory. (memtop = 78c00 membot = 6c018)
tcsh: No entry for terminal type "whatever"
tcsh: using dumb terminal settings.

The patch below fixed it for me (no more error messages from free()).

Onno van der Linden    c/o   vdlinden@fwi.uva.nl (Frank van der Linden)

*** /usr/src/lib/libterm/termcap.c.orig	Tue Jan 25 23:40:52 1994
--- /usr/src/lib/libterm/termcap.c	Sat Apr 16 15:38:10 1994
***************
*** 77,80 ****
--- 77,81 ----
  
  	fname = pvec = pathvec;
+ 	dummy = NULL;
  	tbuf = bp;
  	p = pathbuf;

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