}
	return err
}

func (c *rawConn) Write(f func(uintptr) bool) error {
	if !c.ok() {
		return syscall.EINVAL
	}
	err := c.fd.pfd.RawWrite(f)
	runtime.KeepAlive(c.fd)
	if err != nil {
		err = &OpError{Op: "raw-write", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	return err
}

}

// RawRead invokes the user-defined function f for a read operation.
func (fd *FD) RawRead(f func(uintptr) bool) error {
	return errors.New("not implemented")
}

// RawWrite invokes the user-defined function f for a write operation.
func (fd *FD) RawWrite(f func(uintptr) bool) error {
	return errors.New("not implemented")
}

func DupCloseOnExec(fd int) (int, string, error) {
	nfd, err := syscall.Dup(int(fd), -1)