From 9a16aaa2b9ebef80131a6ae5f342320393933cd6 Mon Sep 17 00:00:00 2001
From: Lorenzo Caminiti <lorcaminiti@gmail.com>
Date: Wed, 15 Feb 2012 00:41:33 +0000
Subject: [PATCH] Added LocalFunction and Utility/IdentityType source files.

[SVN r77024]
---
 include/boost/utility/identity_type.hpp | 45 +++++++++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 include/boost/utility/identity_type.hpp

diff --git a/include/boost/utility/identity_type.hpp b/include/boost/utility/identity_type.hpp
new file mode 100644
index 0000000..c297c49
--- /dev/null
+++ b/include/boost/utility/identity_type.hpp
@@ -0,0 +1,45 @@
+
+// Copyright (C) 2009-2012 Lorenzo Caminiti
+// Distributed under the Boost Software License, Version 1.0
+// (see accompanying file LICENSE_1_0.txt or a copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+// Home at http://www.boost.org/libs/utility/identity_type
+
+/** @file
+Wrap type expressions with round parenthesis so they can be passed to macros
+even if they contain commas.
+*/
+
+#ifndef BOOST_IDENTITY_TYPE_HPP_
+#define BOOST_IDENTITY_TYPE_HPP_
+
+#include <boost/type_traits/function_traits.hpp>
+
+/**
+@brief This macro allows to wrap the specified type expression within extra
+round parenthesis so the type can be passed as a single macro parameter even if
+it contains commas (not already wrapped within round parenthesis).
+
+@Params
+@Param{parenthesized_type,
+The type expression to be passed as macro parameter wrapped by a single set
+of round parenthesis <c>(...)</c>.
+This type expression can contain an arbitrary number of commas.
+}
+@EndParams
+
+This macro works on any C++03 compiler (it does not require variadic macros).
+
+This macro must be prefixed by <c>typename</c> when used within templates.
+However, the compiler will not be able to automatically determine function template parameters when they are wrapped with this macro (these parameters need to
+be explicitly specified when calling the function template).
+
+On some compilers (like GCC), using this macro on an abstract types requires to
+add and remove a reference to the type.
+*/
+#define BOOST_IDENTITY_TYPE(parenthesized_type) \
+    /* must NOT prefix this with `::` to work with parenthesized syntax */ \
+    boost::function_traits< void parenthesized_type >::arg1_type
+
+#endif // #include guard
+