diff --git a/modules/gui/qt/maininterface/compositor.hpp b/modules/gui/qt/maininterface/compositor.hpp
index 53ac8dd11a..ed3efb81af 100644
--- a/modules/gui/qt/maininterface/compositor.hpp
+++ b/modules/gui/qt/maininterface/compositor.hpp
@@ -75,7 +75,7 @@ public:
 
     virtual void unloadGUI() = 0;
 
-    virtual bool setupVoutWindow(vlc_window_t *p_wnd, VoutDestroyCb destroyCb) = 0;
+    [[nodiscard]] virtual bool setupVoutWindow(vlc_window_t *p_wnd, VoutDestroyCb destroyCb) = 0;
 
     virtual Type type() const = 0;