diff --git a/examples/opengl/legacy/shared/qtlogo.h b/examples/opengl/legacy/shared/qtlogo.h
index 9bd15a1431..c5d8db9f9f 100644
--- a/examples/opengl/legacy/shared/qtlogo.h
+++ b/examples/opengl/legacy/shared/qtlogo.h
@@ -44,7 +44,8 @@
 #include <QObject>
 #include <QColor>
 
-class QOpenGLFunctions_1_1;
+QT_FORWARD_DECLARE_CLASS(QOpenGLFunctions_1_1)
+
 class Patch;
 struct Geometry;