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#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
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