AuroraMiddleware/asio
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A memory barrier is needed on some platforms to ensure that all updates

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to the node occur before the tail pointer is updated.
This commit is contained in:
chris_kohlhoff 2008-05-01 22:14:22 +00:00
parent 0534d828f1
commit fa1fbea352
1 changed files with 18 additions and 0 deletions
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18
asio/include/asio/detail/indirect_handler_queue.hpp
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@ -21,6 +21,11 @@
#include "asio/detail/handler_invoke_helpers.hpp"
#include "asio/detail/noncopyable.hpp"
#if defined(_MSC_VER) && (_MSC_VER >= 1310)
extern "C" void _ReadWriteBarrier();
# pragma intrinsic(_ReadWriteBarrier)
#endif // defined(_MSC_VER) && (_MSC_VER >= 1310)
namespace asio {
namespace detail {
@ -194,6 +199,7 @@ public:
next_version_ += 2;
n->handler_ = h;
n->next_ = 0;
memory_barrier();
back_->next_ = n;
back_ = n;
}
@ -245,6 +251,18 @@ private:
Handler handler_;
};
// Helper function to create a memory barrier.
static void memory_barrier()
{
#if defined(_GLIBCXX_WRITE_MEM_BARRIER)
_GLIBCXX_WRITE_MEM_BARRIER;
#elif defined(_MSC_VER) && (_MSC_VER >= 1310)
_ReadWriteBarrier();
#else
# error memory barrier required
#endif
}
// The front of the queue.
node* front_;