1 /*
2  * Distributed under the Boost Software License, Version 1.0.
3  * (See accompanying file LICENSE_1_0.txt or copy at
4  * http://www.boost.org/LICENSE_1_0.txt)
5  *
6  * Copyright (c) 2020 Andrey Semashev
7  */
8 /*!
9  * \file   atomic/detail/once_flag.hpp
10  *
11  * This header declares \c once_flag structure for controlling one time initialization
12  */
13 
14 #ifndef BOOST_ATOMIC_DETAIL_ONCE_FLAG_HPP_INCLUDED_
15 #define BOOST_ATOMIC_DETAIL_ONCE_FLAG_HPP_INCLUDED_
16 
17 #include <boost/atomic/detail/config.hpp>
18 #include <boost/atomic/detail/aligned_variable.hpp>
19 #include <boost/atomic/detail/core_operations.hpp>
20 #include <boost/atomic/detail/header.hpp>
21 
22 #ifdef BOOST_HAS_PRAGMA_ONCE
23 #pragma once
24 #endif
25 
26 namespace boost {
27 namespace atomics {
28 namespace detail {
29 
30 typedef atomics::detail::core_operations< 1u, false, false > once_flag_operations;
31 
32 struct once_flag
33 {
34     BOOST_ATOMIC_DETAIL_ALIGNED_VAR(once_flag_operations::storage_alignment, once_flag_operations::storage_type, m_flag);
35 };
36 
37 } // namespace detail
38 } // namespace atomics
39 } // namespace boost
40 
41 #include <boost/atomic/detail/footer.hpp>
42 
43 #endif // BOOST_ATOMIC_DETAIL_ONCE_FLAG_HPP_INCLUDED_
44