Extracted empty_deleter to Boost.Utility.

[SVN r85577]

include/boost/utility/empty_deleter.hpp

@@ -0,0 +1,43 @@
+/*
+ *          Copyright Andrey Semashev 2007 - 2013.
+ * 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   empty_deleter.hpp
+ * \author Andrey Semashev
+ * \date   22.04.2007
+ *
+ * This header contains an \c empty_deleter implementation. This is an empty
+ * function object that receives a pointer and does nothing with it.
+ * Such empty deletion strategy may be convenient, for example, when
+ * constructing <tt>shared_ptr</tt>s that point to some object that should not be
+ * deleted (i.e. a variable on the stack or some global singleton, like <tt>std::cout</tt>).
+ */
+
+#ifndef BOOST_UTILITY_EMPTY_DELETER_HPP_INCLUDED_
+#define BOOST_UTILITY_EMPTY_DELETER_HPP_INCLUDED_
+
+#include <boost/config.hpp>
+
+#ifdef BOOST_HAS_PRAGMA_ONCE
+#pragma once
+#endif
+
+namespace boost {
+
+//! A function object that does nothing and can be used as an empty deleter for \c shared_ptr
+struct empty_deleter
+{
+    //! Function object result type
+    typedef void result_type;
+    /*!
+     * Does nothing
+     */
+    void operator() (const volatile void*) const BOOST_NOEXCEPT {}
+};
+
+} // namespace boost
+
+#endif // BOOST_UTILITY_EMPTY_DELETER_HPP_INCLUDED_