| /* |
| * Copyright Andrey Semashev 2007 - 2015. |
| * 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 value_extraction_fwd.hpp |
| * \author Andrey Semashev |
| * \date 01.03.2008 |
| * |
| * The header contains forward declaration of tools for extracting attribute values |
| * from the view. |
| */ |
| |
| #ifndef BOOST_LOG_ATTRIBUTES_VALUE_EXTRACTION_FWD_HPP_INCLUDED_ |
| #define BOOST_LOG_ATTRIBUTES_VALUE_EXTRACTION_FWD_HPP_INCLUDED_ |
| |
| #include <boost/log/detail/config.hpp> |
| #include <boost/log/attributes/fallback_policy_fwd.hpp> |
| |
| #ifdef BOOST_HAS_PRAGMA_ONCE |
| #pragma once |
| #endif |
| |
| namespace boost { |
| |
| BOOST_LOG_OPEN_NAMESPACE |
| |
| namespace result_of { |
| |
| /*! |
| * \brief A metafunction that allows to acquire the result of the value extraction |
| */ |
| template< typename T, typename DefaultT = T, typename TagT = void > |
| struct extract_or_default; |
| |
| /*! |
| * \brief A metafunction that allows to acquire the result of the value extraction |
| */ |
| template< typename T, typename TagT = void > |
| struct extract_or_throw; |
| |
| /*! |
| * \brief A metafunction that allows to acquire the result of the value extraction |
| */ |
| template< typename T, typename TagT = void > |
| struct extract; |
| |
| } // namespace result_of |
| |
| /*! |
| * \brief Generic attribute value extractor |
| */ |
| template< typename T, typename FallbackPolicyT = fallback_to_none, typename TagT = void > |
| class value_extractor; |
| |
| BOOST_LOG_CLOSE_NAMESPACE // namespace log |
| |
| } // namespace boost |
| |
| #endif // BOOST_LOG_ATTRIBUTES_VALUE_EXTRACTION_FWD_HPP_INCLUDED_ |