if err == nil {
		fd[0] = int(fdx[0])
		fd[1] = int(fdx[1])
	}
	return
}

var ioSync int64

func CloseOnExec(fd int) { fcntl(fd, F_SETFD, FD_CLOEXEC) }

func SetNonblock(fd int, nonblocking bool) (err error) {
	flag, err := fcntl(fd, F_GETFL, 0)
	if err != nil {
		return err
	}
	if nonblocking {
		flag |= O_NONBLOCK
	} else {
		flag &= ^O_NONBLOCK
	}