diff --git a/sys/sys/sysctl.h b/sys/sys/sysctl.h
index f3173c287078..988dbae94087 100644
--- a/sys/sys/sysctl.h
+++ b/sys/sys/sysctl.h
@@ -186,6 +186,7 @@ struct sysctl_oid {
 
 #define	SYSCTL_IN(r, p, l)	(r->newfunc)(r, p, l)
 #define	SYSCTL_OUT(r, p, l)	(r->oldfunc)(r, p, l)
+#define	SYSCTL_OUT_STR(r, p)	(r->oldfunc)(r, p, strlen(p) + 1)
 
 int sysctl_handle_int(SYSCTL_HANDLER_ARGS);
 int sysctl_msec_to_ticks(SYSCTL_HANDLER_ARGS);