diff --git a/sys/sys/sockio.h b/sys/sys/sockio.h
index b14f3b8c676..93ec3ed6142 100644
--- a/sys/sys/sockio.h
+++ b/sys/sys/sockio.h
@@ -81,7 +81,7 @@
 #define	SIOCGIFCAP	_IOWR('i', 31, struct ifreq)	/* get IF features */
 #define	SIOCGIFINDEX	_IOWR('i', 32, struct ifreq)	/* get IF index */
 #define	SIOCGIFMAC	_IOWR('i', 38, struct ifreq)	/* get IF MAC label */
-#define	SIOCSIFMAC	_IOW('i', 39, struct ifreq)	/* set IF MAC label */
+#define	SIOCSIFMAC	 _IOW('i', 39, struct ifreq)	/* set IF MAC label */
 
 #define	SIOCADDMULTI	 _IOW('i', 49, struct ifreq)	/* add m'cast addr */
 #define	SIOCDELMULTI	 _IOW('i', 50, struct ifreq)	/* del m'cast addr */