1 // 2 // execution/invocable_archetype.hpp 3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 4 // 5 // Copyright (c) 2003-2021 Christopher M. Kohlhoff (chris at kohlhoff dot com) 6 // 7 // Distributed under the Boost Software License, Version 1.0. (See accompanying 8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 9 // 10 11 #ifndef BOOST_ASIO_EXECUTION_INVOCABLE_ARCHETYPE_HPP 12 #define BOOST_ASIO_EXECUTION_INVOCABLE_ARCHETYPE_HPP 13 14 #if defined(_MSC_VER) && (_MSC_VER >= 1200) 15 # pragma once 16 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200) 17 18 #include <boost/asio/detail/config.hpp> 19 #include <boost/asio/detail/type_traits.hpp> 20 #include <boost/asio/detail/variadic_templates.hpp> 21 22 #include <boost/asio/detail/push_options.hpp> 23 24 namespace boost { 25 namespace asio { 26 namespace execution { 27 28 /// An archetypal function object used for determining adherence to the 29 /// execution::executor concept. 30 struct invocable_archetype 31 { 32 #if !defined(GENERATING_DOCUMENTATION) 33 // Necessary for compatibility with a C++03 implementation of result_of. 34 typedef void result_type; 35 #endif // !defined(GENERATING_DOCUMENTATION) 36 37 #if defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) \ 38 || defined(GENERATING_DOCUMENTATION) 39 40 /// Function call operator. 41 template <typename... Args> operator ()boost::asio::execution::invocable_archetype42 void operator()(BOOST_ASIO_MOVE_ARG(Args)...) 43 { 44 } 45 46 #else // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) 47 // || defined(GENERATING_DOCUMENTATION) 48 operator ()boost::asio::execution::invocable_archetype49 void operator()() 50 { 51 } 52 53 #define BOOST_ASIO_PRIVATE_INVOCABLE_ARCHETYPE_CALL_DEF(n) \ 54 template <BOOST_ASIO_VARIADIC_TPARAMS(n)> \ 55 void operator()(BOOST_ASIO_VARIADIC_UNNAMED_MOVE_PARAMS(n)) \ 56 { \ 57 } \ 58 /**/ 59 BOOST_ASIO_VARIADIC_GENERATE(BOOST_ASIO_PRIVATE_INVOCABLE_ARCHETYPE_CALL_DEF) 60 #undef BOOST_ASIO_PRIVATE_INVOCABLE_ARCHETYPE_CALL_DEF 61 62 #endif // defined(BOOST_ASIO_HAS_VARIADIC_TEMPLATES) 63 // || defined(GENERATING_DOCUMENTATION) 64 }; 65 66 } // namespace execution 67 } // namespace asio 68 } // namespace boost 69 70 #include <boost/asio/detail/pop_options.hpp> 71 72 #endif // BOOST_ASIO_EXECUTION_INVOCABLE_ARCHETYPE_HPP 73 74