diff --git a/libguile/ChangeLog b/libguile/ChangeLog
index a1332ce35..06b96ea63 100644
--- a/libguile/ChangeLog
+++ b/libguile/ChangeLog
@@ -1,3 +1,7 @@
+2001-02-08  Keisuke Nishida  <kxn30@po.cwru.edu>
+
+	* ports.c (scm_unread_char): Take an optional argument.
+
 2001-02-08  Marius Vollmer  <marius.vollmer@uni-dortmund.de>
 
 	* modules.h (scm_selected_module, scm_current_module): Renamed
diff --git a/libguile/ports.c b/libguile/ports.c
index 391981bcc..36f59fabb 100644
--- a/libguile/ports.c
+++ b/libguile/ports.c
@@ -1121,7 +1121,7 @@ SCM_DEFINE (scm_peek_char, "peek-char", 0, 1, 0,
 }
 #undef FUNC_NAME
 
-SCM_DEFINE (scm_unread_char, "unread-char", 2, 0, 0,
+SCM_DEFINE (scm_unread_char, "unread-char", 1, 1, 0,
             (SCM cobj, SCM port),
 	    "Place @var{char} in @var{port} so that it will be read by the\n"
 	    "next read operation.  If called multiple times, the unread characters\n"