diff --git a/tests/auc/auc_test.c b/tests/auc/auc_test.c
index 6bf2eb2..61cf82f 100644
--- a/tests/auc/auc_test.c
+++ b/tests/auc/auc_test.c
@@ -509,7 +509,7 @@
 }
 
 /* Test a variety of invalid authentication data combinations */
-void test_gen_vectors_bad_args()
+void test_gen_vectors_bad_args(void)
 {
 	struct osmo_auth_vector vec;
 	uint8_t auts[14];