diff --git a/src/hardware/mooshimeter-dmm/protocol.c b/src/hardware/mooshimeter-dmm/protocol.c
index 38fd3fcc..15aa8f56 100644
--- a/src/hardware/mooshimeter-dmm/protocol.c
+++ b/src/hardware/mooshimeter-dmm/protocol.c
@@ -20,6 +20,7 @@
 #include <config.h>
 #include <gio/gio.h>
 #include <math.h>
+#include <string.h>
 #include "protocol.h"
 
 /*