diff --git a/common/rfb/PixelFormat.h b/common/rfb/PixelFormat.h
index 88e80f4..aef309c 100644
--- a/common/rfb/PixelFormat.h
+++ b/common/rfb/PixelFormat.h
@@ -1,5 +1,6 @@
 /* Copyright (C) 2002-2005 RealVNC Ltd.  All Rights Reserved.
  * Copyright (C) 2011 D. R. Commander.  All Rights Reserved.
+ * Copyright 2009-2014 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
@@ -70,6 +71,7 @@
 
   protected:
     void updateState(void);
+    bool isSane(void);
 
   public:
     int bpp;