1 //
2 // detail/std_fenced_block.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_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.
std_fenced_block(half_t)39   explicit std_fenced_block(half_t)
40   {
41   }
42 
43   // Constructor for a full fenced block.
std_fenced_block(full_t)44   explicit std_fenced_block(full_t)
45   {
46     std::atomic_thread_fence(std::memory_order_acquire);
47   }
48 
49   // Destructor.
~std_fenced_block()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
65