diff --git a/unix/x0vncserver/PollingManager.h b/unix/x0vncserver/PollingManager.h
index 3b922d8..cd83b4c 100644
--- a/unix/x0vncserver/PollingManager.h
+++ b/unix/x0vncserver/PollingManager.h
@@ -137,6 +137,7 @@
 
   int checkRow(int x, int y, int w, bool *pmxChanged);
   void sendChanges(bool *pmxChanged);
+  bool detectVideo(bool *pmxChanged);
 
   void adjustVideoArea();