diff --git a/mes.c b/mes.c
index 4226eb98..f4912bab 100644
--- a/mes.c
+++ b/mes.c
@@ -854,7 +854,8 @@ read_byte ()
 SCM
 unread_byte (SCM i)
 {
-  return ungetchar (VALUE (i));
+  ungetchar (VALUE (i));
+  return i;
 }
 
 SCM