diff --git a/examples/capy_task_arena_executor.hpp b/examples/capy_task_arena_executor.hpp
index fd875dd..af0dbfc 100644
--- a/examples/capy_task_arena_executor.hpp
+++ b/examples/capy_task_arena_executor.hpp
@@ -1,3 +1,5 @@
+#pragma once
+
 #include <tbb/task_arena.h>
 
 #include <boost/capy.hpp>