diff --git a/ndnboost/mpl/aux_/unwrap.hpp b/ndnboost/mpl/aux_/unwrap.hpp
new file mode 100644
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+++ b/ndnboost/mpl/aux_/unwrap.hpp
@@ -0,0 +1,47 @@
+
+#ifndef BOOST_MPL_AUX_UNWRAP_HPP_INCLUDED
+#define BOOST_MPL_AUX_UNWRAP_HPP_INCLUDED
+
+// Copyright Peter Dimov and Multi Media Ltd 2001, 2002
+// Copyright David Abrahams 2001
+//
+// Distributed under the Boost Software License, Version 1.0. 
+// (See accompanying file LICENSE_1_0.txt or copy at 
+// http://www.boost.org/LICENSE_1_0.txt)
+//
+// See http://www.boost.org/libs/mpl for documentation.
+
+// $Id: unwrap.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
+// $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $
+// $Revision: 49267 $
+
+#include <ndnboost/ref.hpp>
+
+namespace ndnboost { namespace mpl { namespace aux {
+
+template< typename F >
+inline
+F& unwrap(F& f, long)
+{
+    return f;
+}
+
+template< typename F >
+inline
+F&
+unwrap(reference_wrapper<F>& f, int)
+{
+    return f;
+}
+
+template< typename F >
+inline
+F&
+unwrap(reference_wrapper<F> const& f, int)
+{
+    return f;
+}
+
+}}}
+
+#endif // BOOST_MPL_AUX_UNWRAP_HPP_INCLUDED