non_const_lvalue.hpp 1.5 KB

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  1. //
  2. // detail/non_const_lvalue.hpp
  3. // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
  4. //
  5. // Copyright (c) 2003-2019 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. #ifndef BOOST_ASIO_DETAIL_NON_CONST_LVALUE_HPP
  11. #define BOOST_ASIO_DETAIL_NON_CONST_LVALUE_HPP
  12. #if defined(_MSC_VER) && (_MSC_VER >= 1200)
  13. # pragma once
  14. #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
  15. #include <boost/asio/detail/config.hpp>
  16. #include <boost/asio/detail/type_traits.hpp>
  17. #include <boost/asio/detail/push_options.hpp>
  18. namespace boost {
  19. namespace asio {
  20. namespace detail {
  21. template <typename T>
  22. struct non_const_lvalue
  23. {
  24. #if defined(BOOST_ASIO_HAS_MOVE)
  25. explicit non_const_lvalue(T& t)
  26. : value(static_cast<typename conditional<
  27. is_same<T, typename decay<T>::type>::value,
  28. typename decay<T>::type&, T&&>::type>(t))
  29. {
  30. }
  31. typename conditional<is_same<T, typename decay<T>::type>::value,
  32. typename decay<T>::type&, typename decay<T>::type>::type value;
  33. #else // defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
  34. explicit non_const_lvalue(const typename decay<T>::type& t)
  35. : value(t)
  36. {
  37. }
  38. typename decay<T>::type value;
  39. #endif // defined(BOOST_ASIO_HAS_MOVE)
  40. };
  41. } // namespace detail
  42. } // namespace asio
  43. } // namespace boost
  44. #include <boost/asio/detail/pop_options.hpp>
  45. #endif // BOOST_ASIO_DETAIL_NON_CONST_LVALUE_HPP