#ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED #define BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED // MS compatible compilers support #pragma once #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma once #endif // // Copyright (c) 2008 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) // #include <boost/detail/interlocked.hpp> #include <boost/smart_ptr/detail/yield_k.hpp> // BOOST_COMPILER_FENCE #if defined(__INTEL_COMPILER) #define BOOST_COMPILER_FENCE __memory_barrier(); #elif defined( _MSC_VER ) && _MSC_VER >= 1310 extern "C" void _ReadWriteBarrier(); #pragma intrinsic( _ReadWriteBarrier ) #define BOOST_COMPILER_FENCE _ReadWriteBarrier(); #elif defined(__GNUC__) #define BOOST_COMPILER_FENCE __asm__ __volatile__( "" : : : "memory" ); #else #define BOOST_COMPILER_FENCE #endif // namespace boost { namespace detail { class spinlock { public: long v_; public: bool try_lock() { long r = BOOST_INTERLOCKED_EXCHANGE( &v_, 1 ); BOOST_COMPILER_FENCE return r == 0; } void lock() { for( unsigned k = 0; !try_lock(); ++k ) { boost::detail::yield( k ); } } void unlock() { BOOST_COMPILER_FENCE *const_cast< long volatile* >( &v_ ) = 0; } public: class scoped_lock { private: spinlock & sp_; scoped_lock( scoped_lock const & ); scoped_lock & operator=( scoped_lock const & ); public: explicit scoped_lock( spinlock & sp ): sp_( sp ) { sp.lock(); } ~scoped_lock() { sp_.unlock(); } }; }; } // namespace detail } // namespace boost #define BOOST_DETAIL_SPINLOCK_INIT {0} #endif // #ifndef BOOST_SMART_PTR_DETAIL_SPINLOCK_W32_HPP_INCLUDED