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diff --git a/boost/vmd/identity.hpp b/boost/vmd/identity.hpp
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+
+//  (C) Copyright Edward Diener 2011-2015
+//  Use, modification and distribution are subject to 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).
+
+#if !defined(BOOST_VMD_IDENTITY_HPP)
+#define BOOST_VMD_IDENTITY_HPP
+
+#include <boost/vmd/detail/setup.hpp>
+
+#if BOOST_PP_VARIADICS
+
+#if BOOST_VMD_MSVC
+#include <boost/preprocessor/cat.hpp>
+#endif
+#include <boost/vmd/empty.hpp>
+
+/*
+
+  The succeeding comments in this file are in doxygen format.
+
+*/
+
+/** \file
+*/
+
+/** \def BOOST_VMD_IDENTITY(item)
+
+    \brief Macro which expands to its argument when invoked with any number of parameters.
+
+    item = any single argument
+    
+    When BOOST_VMD_IDENTITY(item) is subsequently invoked with any number of parameters it expands
+    to 'item'. Subsequently invoking the macro is done as 'BOOST_VMD_IDENTITY(item)(zero_or_more_arguments)'.
+    
+    The macro is equivalent to the Boost PP macro BOOST_PP_IDENTITY(item) with the difference
+    being that BOOST_PP_IDENTITY(item) is always invoked with no arguments, as in
+    'BOOST_VMD_IDENTITY(item)()' whereas BOOST_VMD_IDENTITY can be invoked with any number of
+    arguments.
+    
+    The macro is meant to be used in BOOST_PP_IF and BOOST_PP_IIF statements when only one
+    of the clauses needs to be invoked with calling another macro and the other is meant to
+    return an 'item'.
+    
+    returns = the macro as 'BOOST_VMD_IDENTITY(item)', when invoked with any number of parameters
+              as in '(zero_or_more_arguments)', returns 'item'. The macro itself returns
+              'item BOOST_VMD_EMPTY'.
+    
+*/
+
+#define BOOST_VMD_IDENTITY(item) item BOOST_VMD_EMPTY
+
+/** \def BOOST_VMD_IDENTITY_RESULT(result)
+
+    \brief Macro which wraps any result which can return its value using BOOST_VMD_IDENTITY or 'item BOOST_VMD_EMPTY'.
+
+    result = any single result returned when BOOST_VMD_IDENTITY is used or 'item BOOST_VMD_EMPTY'.
+    
+    The reason for this macro is to smooth over a problem when using VC++ with BOOST_VMD_IDENTITY.
+    If your BOOST_VMD_IDENTITY macro can be used where VC++ is the compiler then you need to
+    surround your macro code which could return a result with this macro in order that VC++ handles
+    BOOST_VMD_IDENTITY correctly.
+    
+    If you are not using VC++ you do not have to use this macro, but doing so does no harm.
+    
+*/
+
+#if BOOST_VMD_MSVC
+#define BOOST_VMD_IDENTITY_RESULT(result) BOOST_PP_CAT(result,)
+#else
+#define BOOST_VMD_IDENTITY_RESULT(result) result
+#endif
+
+#endif /* BOOST_PP_VARIADICS */
+#endif /* BOOST_VMD_IDENTITY_HPP */