From: chris_at_[hidden]
Date: 2008-05-01 18:27:21
Author: chris_kohlhoff
Date: 2008-05-01 18:27:21 EDT (Thu, 01 May 2008)
New Revision: 44998
URL: http://svn.boost.org/trac/boost/changeset/44998
Log:
A memory barrier is needed on some platforms to ensure that all updates
to the node occur before the tail pointer is updated.
Text files modified:
trunk/boost/asio/detail/indirect_handler_queue.hpp | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)
Modified: trunk/boost/asio/detail/indirect_handler_queue.hpp
==============================================================================
--- trunk/boost/asio/detail/indirect_handler_queue.hpp (original)
+++ trunk/boost/asio/detail/indirect_handler_queue.hpp 2008-05-01 18:27:21 EDT (Thu, 01 May 2008)
@@ -21,6 +21,11 @@
#include <boost/asio/detail/handler_invoke_helpers.hpp>
#include <boost/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 boost {
namespace asio {
namespace detail {
@@ -195,6 +200,7 @@
next_version_ += 2;
n->handler_ = h;
n->next_ = 0;
+ memory_barrier();
back_->next_ = n;
back_ = n;
}
@@ -246,6 +252,18 @@
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_;