diff --git a/cv4/list_ops.h b/cv4/list_ops.h
index 14a56d8..39dfabe 100644
--- a/cv4/list_ops.h
+++ b/cv4/list_ops.h
@@ -1,6 +1,7 @@
 #ifndef LIST_OPS_H
 #define LIST_OPS_H
 
+#include <string.h>
 #include <stdlib.h>
 #include <stdbool.h>