diff --git a/lemon/soplex.h b/lemon/soplex.h
--- a/lemon/soplex.h
+++ b/lemon/soplex.h
@@ -144,6 +144,11 @@
 
     virtual void _clear();
 
+    void _messageLevel(MessageLevel m);
+    void _applyMessageLevel();
+
+    int _message_level;
+
   };
 
 } //END OF NAMESPACE LEMON