diff --git a/protocol_event_bus_sender.hpp b/protocol_event_bus_sender.hpp
index 8fe347e..6837b27 100644
--- a/protocol_event_bus_sender.hpp
+++ b/protocol_event_bus_sender.hpp
@@ -1,3 +1,4 @@
+#pragma once
 #include "api/api.hpp"
 namespace iflytop {
 using namespace std;