| #ifndef BOOST_MEMORY_ORDER_HPP_INCLUDED |
| #define BOOST_MEMORY_ORDER_HPP_INCLUDED |
| |
| // MS compatible compilers support #pragma once |
| |
| #if defined(_MSC_VER) && (_MSC_VER >= 1020) |
| # pragma once |
| #endif |
| |
| // boost/memory_order.hpp |
| // |
| // Defines enum boost::memory_order per the C++0x working draft |
| // |
| // Copyright (c) 2008, 2009 Peter Dimov |
| // |
| // Distributed under the Boost Software License, Version 1.0. |
| // See accompanying file LICENSE_1_0.txt or copy at |
| // http://www.boost.org/LICENSE_1_0.txt) |
| |
| |
| namespace boost |
| { |
| |
| // |
| // Enum values are chosen so that code that needs to insert |
| // a trailing fence for acquire semantics can use a single |
| // test such as: |
| // |
| // if( mo & memory_order_acquire ) { ...fence... } |
| // |
| // For leading fences one can use: |
| // |
| // if( mo & memory_order_release ) { ...fence... } |
| // |
| // Architectures such as Alpha that need a fence on consume |
| // can use: |
| // |
| // if( mo & ( memory_order_acquire | memory_order_consume ) ) { ...fence... } |
| // |
| // The values are also in the order of increasing "strength" |
| // of the fences so that success/failure orders can be checked |
| // efficiently in compare_exchange methods. |
| // |
| |
| enum memory_order |
| { |
| memory_order_relaxed = 0, |
| memory_order_consume = 1, |
| memory_order_acquire = 2, |
| memory_order_release = 4, |
| memory_order_acq_rel = 6, // acquire | release |
| memory_order_seq_cst = 14 // acq_rel | 8 |
| }; |
| |
| } // namespace boost |
| |
| #endif // #ifndef BOOST_MEMORY_ORDER_HPP_INCLUDED |
