diff --git a/src/utils/io.h b/src/utils/io.h
index dff691ee0..810510b6d 100644
--- a/src/utils/io.h
+++ b/src/utils/io.h
@@ -3,6 +3,7 @@
 #include <cstdio>
 #include <vector>
 #include <string>
+#include <cstring>
 #include "./utils.h"
 /*!
  * \file io.h