}
	return
}

// Sendmsg sends a message on a socket to an address using the sendmsg system
// call. This function is equivalent to SendmsgN, but does not return the
// number of bytes actually sent.
func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
	_, err = SendmsgN(fd, p, oob, to, flags)
	return
}

// SendmsgN sends a message on a socket to an address using the sendmsg system

	if rsa.Addr.Family != AF_UNSPEC {
		from, err = anyToSockaddr(&rsa)
	}
	return
}

func Sendmsg(fd int, p, oob []byte, to Sockaddr, flags int) (err error) {
	_, err = SendmsgN(fd, p, oob, to, flags)
	return
}

func SendmsgN(fd int, p, oob []byte, to Sockaddr, flags int) (n int, err error) {
	var ptr unsafe.Pointer
	var salen _Socklen
	if to != nil {

	msg.Iovlen = 1
	if n, err = recvmsg(fd, &msg, flags); err != nil {
		return
	}
	oobn = int(msg.Controllen)
	recvflags = int(msg.Flags)
	return
}

//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error)

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(ptr)
	msg.Namelen = uint32(salen)
	var iov Iovec

// In order to use msghdr structure with Control, Controllen, nrecvmsg and nsendmsg must be used.
//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error) = nrecvmsg
//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = nsendmsg

//sys	munmap(addr uintptr, length uintptr) (err error)
//sys	Madvise(b []byte, advice int) (err error)

	}
	if n, err = recvmsg(fd, &msg, flags); err != nil {
		return
	}
	oobn = int(msg.Controllen)
	recvflags = int(msg.Flags)
	return
}

//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error)

func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(unsafe.Pointer(ptr))
	msg.Namelen = uint32(salen)

//sys	Shutdown(s int, how int) (err error)

// In order to use msghdr structure with Control, Controllen in golang.org/x/net,
// nrecvmsg and nsendmsg must be used.
//sys	recvmsg(s int, msg *Msghdr, flags int) (n int, err error) = nrecvmsg
//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = nsendmsg

func (sa *SockaddrInet4) sockaddr() (unsafe.Pointer, _Socklen, error) {
	if sa.Port < 0 || sa.Port > 0xFFFF {
		return nil, 0, EINVAL

	msg.Iov = &iov
	msg.Iovlen = 1
	if n, err = recvmsg(fd, &msg, flags); err != nil {
		return
	}
	oobn = int(msg.Accrightslen)
	return
}

//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = libsocket.__xnet_sendmsg

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(unsafe.Pointer(ptr))
	msg.Namelen = uint32(salen)

		return len(p), nil
	}
}

// WriteMsg wraps the sendmsg network call.
func (fd *FD) WriteMsg(p []byte, oob []byte, sa syscall.Sockaddr) (int, int, error) {
	if err := fd.writeLock(); err != nil {
		return 0, 0, err
	}
	defer fd.writeUnlock()
	if err := fd.pd.prepareWrite(fd.isFile); err != nil {
		return 0, 0, err
	}
	for {
		n, err := syscall.SendmsgN(fd.Sysfd, p, oob, sa, 0)
		if err == syscall.EINTR {

		msg.SetIovlen(len(iov))
	}
	if n, err = recvmsg(fd, &msg, flags); n == -1 {
		return
	}
	oobn = int(msg.Accrightslen)
	return
}

//sys	sendmsg(s int, msg *Msghdr, flags int) (n int, err error) = libsocket.__xnet_sendmsg

func sendmsgN(fd int, iov []Iovec, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(unsafe.Pointer(ptr))

	}
	msg.Iov = &iov
	msg.Iovlen = 1
	if n, err = recvmsg(fd, &msg, flags); err != nil {
		return
	}
	oobn = int(msg.Controllen)
	recvflags = int(msg.Flags)
	return
}

func sendmsgN(fd int, p, oob []byte, ptr unsafe.Pointer, salen _Socklen, flags int) (n int, err error) {
	var msg Msghdr
	msg.Name = (*byte)(ptr)
	msg.Namelen = uint32(salen)
	var iov Iovec
	if len(p) > 0 {
		iov.Base = &p[0]