diff --git a/src/util/scheduler.hpp b/src/util/scheduler.hpp
index b1fb596..18c3004 100644
--- a/src/util/scheduler.hpp
+++ b/src/util/scheduler.hpp
@@ -92,6 +92,8 @@
   EventQueue m_events;
   EventQueue::iterator m_scheduledEvent;
   boost::asio::monotonic_deadline_timer m_deadlineTimer;
+
+  bool m_isEventExecuting;
 };
 
 } // namespace ndn