1 files changed, 5 insertions, 0 deletions
diff --git a/timer.h b/timer.h
index 15e0497..307f0ac 100644
--- a/timer.h
+++ b/timer.h
@@ -1,3 +1,6 @@
+#ifndef UTILS_TIMER_H
+#define UTILS_TIMER_H
+
 #include <cstdint>
 #include <ctime>
 
@@ -62,3 +65,5 @@ struct scoped_timer {
 };
 
 }  // namespace timer
+
+#endif