post.hpp 4.6 KB

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  1. //
  2. // post.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. #ifndef BOOST_ASIO_POST_HPP
  11. #define BOOST_ASIO_POST_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/async_result.hpp>
  17. #include <boost/asio/detail/type_traits.hpp>
  18. #include <boost/asio/execution_context.hpp>
  19. #include <boost/asio/execution/executor.hpp>
  20. #include <boost/asio/is_executor.hpp>
  21. #include <boost/asio/detail/push_options.hpp>
  22. namespace boost {
  23. namespace asio {
  24. /// Submits a completion token or function object for execution.
  25. /**
  26. * This function submits an object for execution using the object's associated
  27. * executor. The function object is queued for execution, and is never called
  28. * from the current thread prior to returning from <tt>post()</tt>.
  29. *
  30. * The use of @c post(), rather than @ref defer(), indicates the caller's
  31. * preference that the function object be eagerly queued for execution.
  32. *
  33. * This function has the following effects:
  34. *
  35. * @li Constructs a function object handler of type @c Handler, initialized
  36. * with <tt>handler(forward<CompletionToken>(token))</tt>.
  37. *
  38. * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
  39. * initializing the object as <tt>result(handler)</tt>.
  40. *
  41. * @li Obtains the handler's associated executor object @c ex by performing
  42. * <tt>get_associated_executor(handler)</tt>.
  43. *
  44. * @li Obtains the handler's associated allocator object @c alloc by performing
  45. * <tt>get_associated_allocator(handler)</tt>.
  46. *
  47. * @li Performs <tt>ex.post(std::move(handler), alloc)</tt>.
  48. *
  49. * @li Returns <tt>result.get()</tt>.
  50. */
  51. template <BOOST_ASIO_COMPLETION_TOKEN_FOR(void()) CompletionToken>
  52. BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, void()) post(
  53. BOOST_ASIO_MOVE_ARG(CompletionToken) token);
  54. /// Submits a completion token or function object for execution.
  55. /**
  56. * This function submits an object for execution using the specified executor.
  57. * The function object is queued for execution, and is never called from the
  58. * current thread prior to returning from <tt>post()</tt>.
  59. *
  60. * The use of @c post(), rather than @ref defer(), indicates the caller's
  61. * preference that the function object be eagerly queued for execution.
  62. *
  63. * This function has the following effects:
  64. *
  65. * @li Constructs a function object handler of type @c Handler, initialized
  66. * with <tt>handler(forward<CompletionToken>(token))</tt>.
  67. *
  68. * @li Constructs an object @c result of type <tt>async_result<Handler></tt>,
  69. * initializing the object as <tt>result(handler)</tt>.
  70. *
  71. * @li Obtains the handler's associated executor object @c ex1 by performing
  72. * <tt>get_associated_executor(handler)</tt>.
  73. *
  74. * @li Creates a work object @c w by performing <tt>make_work(ex1)</tt>.
  75. *
  76. * @li Obtains the handler's associated allocator object @c alloc by performing
  77. * <tt>get_associated_allocator(handler)</tt>.
  78. *
  79. * @li Constructs a function object @c f with a function call operator that
  80. * performs <tt>ex1.dispatch(std::move(handler), alloc)</tt> followed by
  81. * <tt>w.reset()</tt>.
  82. *
  83. * @li Performs <tt>Executor(ex).post(std::move(f), alloc)</tt>.
  84. *
  85. * @li Returns <tt>result.get()</tt>.
  86. */
  87. template <typename Executor,
  88. BOOST_ASIO_COMPLETION_TOKEN_FOR(void()) CompletionToken
  89. BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(Executor)>
  90. BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, void()) post(
  91. const Executor& ex,
  92. BOOST_ASIO_MOVE_ARG(CompletionToken) token
  93. BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(Executor),
  94. typename constraint<
  95. execution::is_executor<Executor>::value || is_executor<Executor>::value
  96. >::type = 0);
  97. /// Submits a completion token or function object for execution.
  98. /**
  99. * @returns <tt>post(ctx.get_executor(), forward<CompletionToken>(token))</tt>.
  100. */
  101. template <typename ExecutionContext,
  102. BOOST_ASIO_COMPLETION_TOKEN_FOR(void()) CompletionToken
  103. BOOST_ASIO_DEFAULT_COMPLETION_TOKEN_TYPE(
  104. typename ExecutionContext::executor_type)>
  105. BOOST_ASIO_INITFN_AUTO_RESULT_TYPE(CompletionToken, void()) post(
  106. ExecutionContext& ctx,
  107. BOOST_ASIO_MOVE_ARG(CompletionToken) token
  108. BOOST_ASIO_DEFAULT_COMPLETION_TOKEN(
  109. typename ExecutionContext::executor_type),
  110. typename constraint<is_convertible<
  111. ExecutionContext&, execution_context&>::value>::type = 0);
  112. } // namespace asio
  113. } // namespace boost
  114. #include <boost/asio/detail/pop_options.hpp>
  115. #include <boost/asio/impl/post.hpp>
  116. #endif // BOOST_ASIO_POST_HPP