1 #ifndef BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED
2 #define BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED
5 // boost/detail/lwm_linux.hpp
7 // Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
9 // Distributed under the Boost Software License, Version 1.0. (See
10 // accompanying file LICENSE_1_0.txt or copy at
11 // http://www.boost.org/LICENSE_1_0.txt)
15 // This implementation uses <asm/atomic.h>. This is a kernel header;
16 // using kernel headers in a user program may cause a number of problems,
17 // and not all flavors of Linux provide the atomic instructions.
19 // This file is only provided because the performance of this implementation
20 // is about 3.5 times higher than the pthreads version. Use at your own risk
21 // (by defining BOOST_USE_ASM_ATOMIC_H.)
24 #include <asm/atomic.h>
33 class lightweight_mutex
39 lightweight_mutex(lightweight_mutex const &);
40 lightweight_mutex & operator=(lightweight_mutex const &);
46 atomic_t a = ATOMIC_INIT(1);
51 friend class scoped_lock;
57 lightweight_mutex & m_;
59 scoped_lock(scoped_lock const &);
60 scoped_lock & operator=(scoped_lock const &);
64 explicit scoped_lock(lightweight_mutex & m): m_(m)
66 while( !atomic_dec_and_test(&m_.a_) )
84 #endif // #ifndef BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED