diff --git a/unix/vncviewer/DesktopWindow.cxx b/unix/vncviewer/DesktopWindow.cxx
index 657572a..8919859 100644
--- a/unix/vncviewer/DesktopWindow.cxx
+++ b/unix/vncviewer/DesktopWindow.cxx
@@ -254,7 +254,7 @@
     setColourMapEntriesTimer.start(100);
 }
 
-void DesktopWindow::serverCutText(const char* str, int len)
+void DesktopWindow::serverCutText(const char* str, rdr::U32 len)
 {
   if (acceptClipboard) {
     newServerCutText = true;