diff --git a/unix/vncviewer/CConn.cxx b/unix/vncviewer/CConn.cxx
index 8a9dfcf..fed6db3 100644
--- a/unix/vncviewer/CConn.cxx
+++ b/unix/vncviewer/CConn.cxx
@@ -389,7 +389,7 @@
 
 void CConn::bell() { XBell(dpy, 0); }
 
-void CConn::serverCutText(const char* str, int len) {
+void CConn::serverCutText(const char* str, rdr::U32 len) {
   desktop->serverCutText(str,len);
 }