diff --git a/common/rfb/CMsgWriter.cxx b/common/rfb/CMsgWriter.cxx
index 26e0d50..8948cbd 100644
--- a/common/rfb/CMsgWriter.cxx
+++ b/common/rfb/CMsgWriter.cxx
@@ -124,7 +124,7 @@
 }
 
 
-void CMsgWriter::clientCutText(const char* str, int len)
+void CMsgWriter::clientCutText(const char* str, rdr::U32 len)
 {
   startMsg(msgTypeClientCutText);
   os->pad(3);