1 files changed, 61 insertions, 0 deletions
diff --git a/ext/asio/detail/gcc_x86_fenced_block.hpp b/ext/asio/detail/gcc_x86_fenced_block.hpp
new file mode 100644
index 0000000000..48119f4c39
--- /dev/null
+++ b/ext/asio/detail/gcc_x86_fenced_block.hpp
@@ -0,0 +1,61 @@
+//
+// gcc_x86_fenced_block.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2010 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// 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)
+//
+
+#ifndef ASIO_DETAIL_GCC_X86_FENCED_BLOCK_HPP
+#define ASIO_DETAIL_GCC_X86_FENCED_BLOCK_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/push_options.hpp"
+
+#include "asio/detail/push_options.hpp"
+#include <boost/config.hpp>
+#include "asio/detail/pop_options.hpp"
+
+#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+
+namespace asio {
+namespace detail {
+
+class gcc_x86_fenced_block
+  : private noncopyable
+{
+public:
+  // Constructor.
+  gcc_x86_fenced_block()
+  {
+    barrier();
+  }
+
+  // Destructor.
+  ~gcc_x86_fenced_block()
+  {
+    barrier();
+  }
+
+private:
+  static int barrier()
+  {
+    int r = 0;
+    __asm__ __volatile__ ("xchgl %%eax, %0" : "=m" (r) : : "memory", "cc");
+    return r;
+  }
+};
+
+} // namespace detail
+} // namespace asio
+
+#endif // defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_DETAIL_GCC_X86_FENCED_BLOCK_HPP