Imported existing code

libraries/include/boost/python/has_back_reference.hpp

@@ -0,0 +1,24 @@
+// Copyright David Abrahams 2002.
+// 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)
+#ifndef HAS_BACK_REFERENCE_DWA2002323_HPP
+# define HAS_BACK_REFERENCE_DWA2002323_HPP
+
+# include <boost/python/detail/prefix.hpp>
+# include <boost/mpl/bool.hpp>
+
+namespace boost { namespace python { 
+
+// traits class which users can specialize to indicate that a class
+// contains a back-reference to its owning PyObject*
+template <class T>
+struct has_back_reference
+  : mpl::false_
+{
+};
+
+
+}} // namespace boost::python
+
+#endif // HAS_BACK_REFERENCE_DWA2002323_HPP