Hi, it's better to compare memcmp against 0, for clarity.
fritjof Index: diff3.c =================================================================== RCS file: /cvs/src/usr.bin/rcs/diff3.c,v retrieving revision 1.33 diff -u -p -r1.33 diff3.c --- diff3.c 4 Mar 2012 04:05:15 -0000 1.33 +++ diff3.c 21 Jun 2014 21:03:30 -0000 @@ -517,7 +517,7 @@ ed_patch_lines(struct rcs_lines *dlines, if (lp == NULL) errx(1, "ed_patch_lines"); - if (!memcmp(lp->l_line, ".", 1)) + if (memcmp(lp->l_line, ".", 1) == 0) break; TAILQ_REMOVE(&(plines->l_lines), lp, l_list);