diff --git a/lemon/lp_skeleton.h b/lemon/lp_skeleton.h
--- a/lemon/lp_skeleton.h
+++ b/lemon/lp_skeleton.h
@@ -140,6 +140,8 @@
     ///\e
     virtual void _clear();
 
+    ///\e
+    virtual void _messageLevel(MessageLevel);
   };
 
   /// \brief Skeleton class for an LP solver interface