diff --git a/common/rfb/CMsgHandler.h b/common/rfb/CMsgHandler.h
index 5e333d2..7d2cdc2 100644
--- a/common/rfb/CMsgHandler.h
+++ b/common/rfb/CMsgHandler.h
@@ -46,7 +46,7 @@
     // methods to set the members of cp appropriately.
 
     virtual void setDesktopSize(int w, int h);
-    virtual void setExtendedDesktopSize(int reason, int result,
+    virtual void setExtendedDesktopSize(unsigned reason, unsigned result,
                                         int w, int h,
                                         const ScreenSet& layout);
     virtual void setCursor(int width, int height, const Point& hotspot,