diff --git a/ds/array.c b/ds/array.c
index 0c6d56e..e8be7ad 100644
--- a/ds/array.c
+++ b/ds/array.c
@@ -307,7 +307,7 @@ static void array_fini(b_object *obj, void *priv)
 	}
 }
 
-static void array_to_string(const b_object *obj, struct b_stream *out)
+static void array_to_string(const b_object *obj, b_stream *out)
 {
 	struct b_array_p *array = b_object_get_private(obj, B_TYPE_ARRAY);