diff --git a/log-tree.h b/log-tree.h
index 8946ff3..59ba4c4 100644
--- a/log-tree.h
+++ b/log-tree.h
@@ -11,7 +11,7 @@
 int log_tree_diff_flush(struct rev_info *);
 int log_tree_commit(struct rev_info *, struct commit *);
 int log_tree_opt_parse(struct rev_info *, const char **, int);
-void show_log(struct rev_info *opt, const char *sep);
+void show_log(struct rev_info *opt);
 void show_decorations(struct commit *commit);
 void log_write_email_headers(struct rev_info *opt, const char *name,
 			     const char **subject_p,