diff --git a/cmd/zpool/zpool_iter.c b/cmd/zpool/zpool_iter.c
index 8cf6bab42..65e53f8e0 100644
--- a/cmd/zpool/zpool_iter.c
+++ b/cmd/zpool/zpool_iter.c
@@ -63,10 +63,10 @@ struct zpool_list {
 	zfs_type_t	zl_type;
 };
 
-/* ARGSUSED */
 static int
 zpool_compare(const void *larg, const void *rarg, void *unused)
 {
+	(void) unused;
 	zpool_handle_t *l = ((zpool_node_t *)larg)->zn_handle;
 	zpool_handle_t *r = ((zpool_node_t *)rarg)->zn_handle;
 	const char *lname = zpool_get_name(l);