ptr   unsafe.Pointer
		salen _Socklen
	)
	if to != nil {
		ptr, salen, err = to.sockaddr()
		if err != nil {
			return err
		}
	}
	return sendto(fd, p, flags, ptr, salen)
}

func SetsockoptByte(fd, level, opt int, value byte) (err error) {
	return setsockopt(fd, level, opt, unsafe.Pointer(&value), 1)
}

func SetsockoptInt(fd, level, opt int, value int) (err error) {
	var n = int32(value)