diff --git a/unix/vncviewer/CConn.h b/unix/vncviewer/CConn.h
index 3bf0a82..e3f17c3 100644
--- a/unix/vncviewer/CConn.h
+++ b/unix/vncviewer/CConn.h
@@ -80,7 +80,7 @@
   void setName(const char* name);
   void setColourMapEntries(int firstColour, int nColours, rdr::U16* rgbs);
   void bell();
-  void serverCutText(const char* str, int len);
+  void serverCutText(const char* str, rdr::U32 len);
   void framebufferUpdateStart();
   void framebufferUpdateEnd();
   void beginRect(const rfb::Rect& r, unsigned int encoding);