Imported Upstream version 1.57.0upstream/1.57.0

1 files changed, 67 insertions, 0 deletions

diff --git a/boost/log/expressions/is_keyword_descriptor.hpp b/boost/log/expressions/is_keyword_descriptor.hpp
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+++ b/boost/log/expressions/is_keyword_descriptor.hpp
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+/*
+ *          Copyright Andrey Semashev 2007 - 2014.
+ * 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   is_keyword_descriptor.hpp
+ * \author Andrey Semashev
+ * \date   14.07.2012
+ *
+ * The header contains attribute keyword descriptor detection trait.
+ */
+
+#ifndef BOOST_LOG_EXPRESSIONS_IS_KEYWORD_DESCRIPTOR_HPP_INCLUDED_
+#define BOOST_LOG_EXPRESSIONS_IS_KEYWORD_DESCRIPTOR_HPP_INCLUDED_
+
+#include <boost/mpl/bool.hpp>
+#include <boost/log/detail/config.hpp>
+#include <boost/log/detail/header.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+BOOST_LOG_OPEN_NAMESPACE
+
+namespace expressions {
+
+/*!
+ * Base class for keyword descriptors. All keyword descriptors must derive from this class to support the \c is_keyword_descriptor trait.
+ */
+struct keyword_descriptor
+{
+#ifndef BOOST_LOG_DOXYGEN_PASS
+    typedef void _is_boost_log_keyword_descriptor;
+#endif // BOOST_LOG_DOXYGEN_PASS
+};
+
+/*!
+ * The metafunction detects if the type \c T is a keyword descriptor
+ */
+template< typename T, typename VoidT = void >
+struct is_keyword_descriptor :
+    public mpl::false_
+{
+};
+
+#ifndef BOOST_LOG_DOXYGEN_PASS
+template< typename T >
+struct is_keyword_descriptor< T, typename T::_is_boost_log_keyword_descriptor > :
+    public mpl::true_
+{
+};
+#endif
+
+} // namespace expressions
+
+BOOST_LOG_CLOSE_NAMESPACE // namespace log
+
+} // namespace boost
+
+#include <boost/log/detail/footer.hpp>
+
+#endif // BOOST_LOG_EXPRESSIONS_IS_KEYWORD_DESCRIPTOR_HPP_INCLUDED_