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;
diff --git a/unix/vncviewer/DesktopWindow.h b/unix/vncviewer/DesktopWindow.h
index a1af750..fe5ef82 100644
--- a/unix/vncviewer/DesktopWindow.h
+++ b/unix/vncviewer/DesktopWindow.h
@@ -55,7 +55,7 @@
 
   // Methods forwarded from CConn
   void setColourMapEntries(int firstColour, int nColours, rdr::U16* rgbs);
-  void serverCutText(const char* str, int len);
+  void serverCutText(const char* str, rdr::U32 len);
   void framebufferUpdateEnd();
 
   void fillRect(const rfb::Rect& r, rfb::Pixel pix) {