ceph/src/boost/boost/asio/detail/std_fenced_block.hpp

   1 //
   2 // detail/std_fenced_block.hpp
   3 // ~~~~~~~~~~~~~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2017 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_DETAIL_STD_FENCED_BLOCK_HPP
  12 #define BOOST_ASIO_DETAIL_STD_FENCED_BLOCK_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
  20 #if defined(BOOST_ASIO_HAS_STD_ATOMIC)
  21
  22 #include <atomic>
  23 #include <boost/asio/detail/noncopyable.hpp>
  24
  25 #include <boost/asio/detail/push_options.hpp>
  26
  27 namespace boost {
  28 namespace asio {
  29 namespace detail {
  30
  31 class std_fenced_block
  32   : private noncopyable
  33 {
  34 public:
  35   enum half_t { half };
  36   enum full_t { full };
  37
  38   // Constructor for a half fenced block.
  39   explicit std_fenced_block(half_t)
  40   {
  41   }
  42
  43   // Constructor for a full fenced block.
  44   explicit std_fenced_block(full_t)
  45   {
  46     std::atomic_thread_fence(std::memory_order_acquire);
  47   }
  48
  49   // Destructor.
  50   ~std_fenced_block()
  51   {
  52     std::atomic_thread_fence(std::memory_order_release);
  53   }
  54 };
  55
  56 } // namespace detail
  57 } // namespace asio
  58 } // namespace boost
  59
  60 #include <boost/asio/detail/pop_options.hpp>
  61
  62 #endif // defined(BOOST_ASIO_HAS_STD_ATOMIC)
  63
  64 #endif // BOOST_ASIO_DETAIL_STD_FENCED_BLOCK_HPP