1 #ifndef BOOST_DETAIL_LWM_WIN32_HPP_INCLUDED
2 #define BOOST_DETAIL_LWM_WIN32_HPP_INCLUDED
9 // boost/detail/lwm_win32.hpp
11 // Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
13 // Permission to copy, use, modify, sell and distribute this software
14 // is granted provided this copyright notice appears in all copies.
15 // This software is provided "as is" without express or implied
16 // warranty, and with no claim as to its suitability for any purpose.
19 #include <boost/detail/winapi.hpp>
27 class lightweight_mutex
33 lightweight_mutex(lightweight_mutex const &);
34 lightweight_mutex & operator=(lightweight_mutex const &);
38 lightweight_mutex(): l_(0)
43 friend class scoped_lock;
49 lightweight_mutex & m_;
51 scoped_lock(scoped_lock const &);
52 scoped_lock & operator=(scoped_lock const &);
56 explicit scoped_lock(lightweight_mutex & m): m_(m)
58 while( winapi::InterlockedExchange(&m_.l_, 1) )
66 winapi::InterlockedExchange(&m_.l_, 0);
68 // Note: adding a Sleep(0) here will make
69 // the mutex more fair and will increase the overall
70 // performance of some applications substantially in
71 // high contention situations, but will penalize the
72 // low contention / single thread case up to 5x
81 #endif // #ifndef BOOST_DETAIL_LWM_WIN32_HPP_INCLUDED