diff --git a/libratbox/src/commio.c b/libratbox/src/commio.c
index 4d24f018..369edba6 100644
--- a/libratbox/src/commio.c
+++ b/libratbox/src/commio.c
@@ -772,7 +772,7 @@ rb_listen(rb_fde_t *F, int backlog, int defer_accept)
 #ifdef TCP_DEFER_ACCEPT
 	if (defer_accept && !result)
 	{
-		setsockopt(F->fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &backlog, sizeof(int));
+		(void)setsockopt(F->fd, IPPROTO_TCP, TCP_DEFER_ACCEPT, &backlog, sizeof(int));
 	}
 #endif
 #ifdef SO_ACCEPTFILTER