1 /*
2  *          Copyright Andrey Semashev 2007 - 2015.
3  * Distributed under the Boost Software License, Version 1.0.
4  *    (See accompanying file LICENSE_1_0.txt or copy at
5  *          http://www.boost.org/LICENSE_1_0.txt)
6  */
7 /*!
8  * \file   attr_fwd.hpp
9  * \author Andrey Semashev
10  * \date   21.07.2012
11  *
12  * The header contains forward declaration of a generic attribute placeholder in template expressions.
13  */
14 
15 #ifndef BOOST_LOG_EXPRESSIONS_ATTR_FWD_HPP_INCLUDED_
16 #define BOOST_LOG_EXPRESSIONS_ATTR_FWD_HPP_INCLUDED_
17 
18 #include <boost/log/detail/config.hpp>
19 #include <boost/log/attributes/fallback_policy_fwd.hpp>
20 
21 #ifdef BOOST_HAS_PRAGMA_ONCE
22 #pragma once
23 #endif
24 
25 namespace boost {
26 
27 #ifndef BOOST_LOG_DOXYGEN_PASS
28 
29 namespace phoenix {
30 
31 template< typename >
32 struct actor;
33 
34 } // namespace phoenix
35 
36 #endif
37 
38 BOOST_LOG_OPEN_NAMESPACE
39 
40 namespace expressions {
41 
42 /*!
43  * An attribute value extraction terminal
44  */
45 template<
46     typename T,
47     typename FallbackPolicyT = fallback_to_none,
48     typename TagT = void
49 >
50 class attribute_terminal;
51 
52 /*!
53  * An attribute value extraction terminal actor
54  */
55 template<
56     typename T,
57     typename FallbackPolicyT = fallback_to_none,
58     typename TagT = void,
59     template< typename > class ActorT = phoenix::actor
60 >
61 class attribute_actor;
62 
63 } // namespace expressions
64 
65 BOOST_LOG_CLOSE_NAMESPACE // namespace log
66 
67 } // namespace boost
68 
69 #endif // BOOST_LOG_EXPRESSIONS_ATTR_FWD_HPP_INCLUDED_
70