diff --git a/include/header.h b/include/header.h
index 2ecd9200..ff2ceead 100644
--- a/include/header.h
+++ b/include/header.h
@@ -27,6 +27,7 @@
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <fcntl.h>
 
 #ifndef ATTRIBUTE_UNUSED