3 files changed, 14 insertions, 0 deletions
diff --git a/examples/opengl/hellowindow/hellowindow.h b/examples/opengl/hellowindow/hellowindow.h
index d4dcbcf3db..3934cbf074 100644
--- a/examples/opengl/hellowindow/hellowindow.h
+++ b/examples/opengl/hellowindow/hellowindow.h
@@ -48,6 +48,9 @@
 **
 ****************************************************************************/
 
+#ifndef HELLOWINDOW_H
+#define HELLOWINDOW_H
+
 #include <QWindow>
 
 #include <QColor>
@@ -117,3 +120,5 @@ private:
     QColor m_color;
     const QSharedPointer<Renderer> m_renderer;
 };
+
+#endif // HELLOWINDOW_H
diff --git a/examples/opengl/openglwindow/openglwindow.h b/examples/opengl/openglwindow/openglwindow.h
index 8db943ddde..f824c22c9f 100644
--- a/examples/opengl/openglwindow/openglwindow.h
+++ b/examples/opengl/openglwindow/openglwindow.h
@@ -48,6 +48,9 @@
 **
 ****************************************************************************/
 
+#ifndef OPENGLWINDOW_H
+#define OPENGLWINDOW_H
+
 #include <QWindow>
 #include <QOpenGLFunctions>
 
@@ -89,3 +92,4 @@ private:
 };
 //! [1]
 
+#endif // OPENGLWINDOW_H
diff --git a/examples/opengl/paintedwindow/paintedwindow.h b/examples/opengl/paintedwindow/paintedwindow.h
index 972d8d10bd..14964e35ff 100644
--- a/examples/opengl/paintedwindow/paintedwindow.h
+++ b/examples/opengl/paintedwindow/paintedwindow.h
@@ -48,6 +48,9 @@
 **
 ****************************************************************************/
 
+#ifndef PAINTEDWINDOW_H
+#define PAINTEDWINDOW_H
+
 #include <QWindow>
 
 #include <QtGui/qopengl.h>
@@ -102,3 +105,5 @@ private:
     QPropertyAnimation *m_animation;
     QTimer *m_paintTimer;
 };
+
+#endif // PAINTEDWINDOW_H