diff --git a/lib/bitunpack.c b/lib/bitunpack.c
index 5ce4062..4506008 100644
--- a/lib/bitunpack.c
+++ b/lib/bitunpack.c
@@ -26,6 +26,7 @@
 #pragma warning( disable : 4090)
 #pragma warning( disable : 4068)
 
+#include <string.h>
 #include "include_/conf.h"
 #include "include_/bitpack.h"
 #include "include_/bitutil.h"