diff --git a/test/imp/test_imp_fmt.cpp b/test/imp/test_imp_fmt.cpp
index 8836800..3a50a66 100644
--- a/test/imp/test_imp_fmt.cpp
+++ b/test/imp/test_imp_fmt.cpp
@@ -1,6 +1,7 @@
 #define _CRT_SECURE_NO_WARNINGS
 #include <iostream>
 #include <tuple>
+#include <cstring>
 
 #include "gtest/gtest.h"