diff --git a/common/rfb/CMsgWriter.h b/common/rfb/CMsgWriter.h
index 37755e7..e5cc590 100644
--- a/common/rfb/CMsgWriter.h
+++ b/common/rfb/CMsgWriter.h
@@ -1,4 +1,5 @@
 /* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
+ * Copyright 2009-2011 Pierre Ossman for Cendio AB
  * 
  * This is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -44,6 +45,7 @@
 
     virtual void writeSetDesktopSize(int width, int height,
                                      const ScreenSet& layout)=0;
+    virtual void writeFence(rdr::U32 flags, unsigned len, const char data[])=0;
 
     // CMsgWriter implemented methods
     virtual void writeSetPixelFormat(const PixelFormat& pf);