diff --git a/sys/sys/sockopt.h b/sys/sys/sockopt.h
--- a/sys/sys/sockopt.h
+++ b/sys/sys/sockopt.h
@@ -57,8 +57,10 @@
 
 int	sosetopt(struct socket *so, struct sockopt *sopt);
 int	sogetopt(struct socket *so, struct sockopt *sopt);
-int	sooptcopyin(struct sockopt *sopt, void *buf, size_t len, size_t minlen);
-int	sooptcopyout(struct sockopt *sopt, const void *buf, size_t len);
+int __result_use_check sooptcopyin(struct sockopt *sopt, void *buf, size_t len,
+    size_t minlen);
+int __result_use_check sooptcopyout(struct sockopt *sopt, const void *buf,
+    size_t len);
 int	soopt_getm(struct sockopt *sopt, struct mbuf **mp);
 int	soopt_mcopyin(struct sockopt *sopt, struct mbuf *m);
 int	soopt_mcopyout(struct sockopt *sopt, struct mbuf *m);