diff --git a/utils/osmo-aka-verify.c b/utils/osmo-aka-verify.c
index bbc65ef..f23c349 100644
--- a/utils/osmo-aka-verify.c
+++ b/utils/osmo-aka-verify.c
@@ -88,7 +88,7 @@
 }
 
 
-static void help()
+static void help(void)
 {
 	printf( "Static SIM card parameters:\n"
 		"-k  --key\tSpecify Ki / K\n"