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+// Boost.Bimap
+//
+// Copyright (c) 2006-2007 Matias Capeletto
+//
+// 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)
+
+/// \file tags/support/tag_of.hpp
+/// \brief Safe way to acces the tag of a type
+
+#ifndef BOOST_BIMAP_TAGS_SUPPORT_TAG_OF_HPP
+#define BOOST_BIMAP_TAGS_SUPPORT_TAG_OF_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER>=1200)
+#pragma once
+#endif
+
+#include <boost/config.hpp>
+
+#include <boost/bimap/tags/tagged.hpp>
+#include <boost/bimap/detail/debug/static_error.hpp>
+
+/** \struct boost::bimaps::tags::support::tag_of
+\brief Metafunction to obtain the tag of a type.
+
+\code
+template< class TaggedType >
+struct tag_of
+{
+ typedef {Tag} type;
+};
+\endcode
+
+If the type is not tagged you will get a compile timer error with the following message:
+
+\verbatim
+USING_TAG_OF_WITH_AN_UNTAGGED_TYPE, TaggedType
+\endverbatim
+
+See also tagged, value_type_of.
+ **/
+
+#ifndef BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES
+
+namespace boost {
+namespace bimaps {
+namespace tags {
+namespace support {
+
+
+// tag_of metafunction
+
+template< class Type >
+struct tag_of
+{
+ BOOST_BIMAP_STATIC_ERROR( USING_TAG_OF_WITH_AN_UNTAGGED_TYPE, (Type) );
+};
+
+template< class Type, class Tag >
+struct tag_of< tagged< Type, Tag > >
+{
+ typedef Tag type;
+};
+
+
+} // namespace support
+} // namespace tags
+} // namespace bimaps
+} // namespace boost
+
+#endif // BOOST_BIMAP_DOXYGEN_WILL_NOT_PROCESS_THE_FOLLOWING_LINES
+
+#endif // BOOST_BIMAP_TAGS_SUPPORT_TAG_OF_HPP
+