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1 | #ifndef BOOST_MEMORY_ORDER_HPP_INCLUDED |
2 | #define BOOST_MEMORY_ORDER_HPP_INCLUDED | |
3 | ||
4 | // MS compatible compilers support #pragma once | |
5 | ||
6 | #if defined(_MSC_VER) && (_MSC_VER >= 1020) | |
7 | # pragma once | |
8 | #endif | |
9 | ||
10 | // boost/memory_order.hpp | |
11 | // | |
12 | // Defines enum boost::memory_order per the C++0x working draft | |
13 | // | |
14 | // Copyright (c) 2008, 2009 Peter Dimov | |
15 | // | |
16 | // Distributed under the Boost Software License, Version 1.0. | |
17 | // See accompanying file LICENSE_1_0.txt or copy at | |
18 | // http://www.boost.org/LICENSE_1_0.txt) | |
19 | ||
20 | ||
21 | namespace boost | |
22 | { | |
23 | ||
24 | // | |
25 | // Enum values are chosen so that code that needs to insert | |
26 | // a trailing fence for acquire semantics can use a single | |
27 | // test such as: | |
28 | // | |
29 | // if( mo & memory_order_acquire ) { ...fence... } | |
30 | // | |
31 | // For leading fences one can use: | |
32 | // | |
33 | // if( mo & memory_order_release ) { ...fence... } | |
34 | // | |
35 | // Architectures such as Alpha that need a fence on consume | |
36 | // can use: | |
37 | // | |
38 | // if( mo & ( memory_order_acquire | memory_order_consume ) ) { ...fence... } | |
39 | // | |
40 | // The values are also in the order of increasing "strength" | |
41 | // of the fences so that success/failure orders can be checked | |
42 | // efficiently in compare_exchange methods. | |
43 | // | |
44 | ||
45 | enum memory_order | |
46 | { | |
47 | memory_order_relaxed = 0, | |
48 | memory_order_consume = 1, | |
49 | memory_order_acquire = 2, | |
50 | memory_order_release = 4, | |
51 | memory_order_acq_rel = 6, // acquire | release | |
52 | memory_order_seq_cst = 14 // acq_rel | 8 | |
53 | }; | |
54 | ||
55 | } // namespace boost | |
56 | ||
57 | #endif // #ifndef BOOST_MEMORY_ORDER_HPP_INCLUDED |