Added boost header

test/external/boost/signals2/trackable.hpp

@@ -0,0 +1,49 @@
+// Boost.Signals2 library
+
+// Copyright Frank Mori Hess 2007,2009.
+// Copyright Timmo Stange 2007.
+// Copyright Douglas Gregor 2001-2004. Use, modification and
+// distribution is subject to 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)
+
+// Compatibility class to ease porting from the original
+// Boost.Signals library.  However,
+// boost::signals2::trackable is NOT thread-safe.
+
+// For more information, see http://www.boost.org
+
+#ifndef BOOST_SIGNALS2_TRACKABLE_HPP
+#define BOOST_SIGNALS2_TRACKABLE_HPP
+
+#include <boost/assert.hpp>
+#include <boost/shared_ptr.hpp>
+
+namespace boost {
+  namespace signals2 {
+    namespace detail
+    {
+        class tracked_objects_visitor;
+    }
+    class trackable {
+    protected:
+      trackable(): _tracked_ptr(static_cast<int*>(0)) {}
+      trackable(const trackable &): _tracked_ptr(static_cast<int*>(0)) {}
+      trackable& operator=(const trackable &)
+      {
+          return *this;
+      }
+      ~trackable() {}
+    private:
+      friend class detail::tracked_objects_visitor;
+      const shared_ptr<void>& get_shared_ptr() const
+      {
+          return _tracked_ptr;
+      }
+
+      shared_ptr<void> _tracked_ptr;
+    };
+  } // end namespace signals2
+} // end namespace boost
+
+#endif // BOOST_SIGNALS2_TRACKABLE_HPP