diff --git a/wrap/gl/gl_type_name.h b/wrap/gl/gl_type_name.h
index f56f24b2..fa1b8fbc 100644
--- a/wrap/gl/gl_type_name.h
+++ b/wrap/gl/gl_type_name.h
@@ -21,6 +21,9 @@
 *                                                                           *
 ****************************************************************************/
 
+#ifndef __VCG_GL_TYPE_NAME
+#define __VCG_GL_TYPE_NAME
+
 namespace vcg 
 {
 	template <typename T>
@@ -38,4 +41,6 @@ namespace vcg
 	typedef GLdouble ScalarType;
 	static GLenum SCALAR() { return GL_DOUBLE; }
 	};
-}
\ No newline at end of file
+}
+
+#endif
\ No newline at end of file