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 // Permission to copy, use, modify, sell and distribute this software
10 // is granted provided this copyright notice appears in all copies.
11 // This software is provided "as is" without express or implied
12 // warranty, and with no claim as to its suitability for any purpose.
16 // This implementation uses <asm/atomic.h>. This is a kernel header;
17 // using kernel headers in a user program may cause a number of problems,
18 // and not all flavors of Linux provide the atomic instructions.
20 // This file is only provided because the performance of this implementation
21 // is about 3.5 times higher than the pthreads version. Use at your own risk
22 // (by defining BOOST_USE_ASM_ATOMIC_H.)
25 #include <asm/atomic.h>
34 class lightweight_mutex
40 lightweight_mutex(lightweight_mutex const &);
41 lightweight_mutex & operator=(lightweight_mutex const &);
47 atomic_t a = ATOMIC_INIT(1);
52 friend class scoped_lock;
58 lightweight_mutex & m_;
60 scoped_lock(scoped_lock const &);
61 scoped_lock & operator=(scoped_lock const &);
65 explicit scoped_lock(lightweight_mutex & m): m_(m)
67 while( !atomic_dec_and_test(&m_.a_) )
85 #endif // #ifndef BOOST_DETAIL_LWM_LINUX_HPP_INCLUDED