RLOG_ERRNO
RLOG_ERRNO("unable to open interface %s", ifname);
RLOG_ERRNO("socket");
RLOG_ERRNO("ioctl(SIOCGIFFLAGS)");
RLOG_ERRNO("ioctl(SIOSGIFFLAGS)");
RLOG_ERRNO("ioctl(SIOCGIFINFO_IN6)");
RLOG_ERRNO("ioctl(SIOCSIFINFO_IN6)");
RLOG_ERRNO("jail %s attach failed: ret=%d", vnet_name, errno);
RLOG_ERRNO("inet_ntop() failed: ret=%d", error);
RLOG_ERRNO("setsockopt failed");