func (c *UnixConn) SyscallConn() (syscall.RawConn, error) {
	if !c.ok() {
		return nil, syscall.EINVAL
	}
	return newRawConn(c.fd), nil
}

// CloseRead shuts down the reading side of the Unix domain connection.
// Most callers should just use Close.
func (c *UnixConn) CloseRead() error {
	if !c.ok() {
		return syscall.EINVAL
	}
	if err := c.fd.closeRead(); err != nil {

	if !c.ok() {
		return syscall.EINVAL
	}
	err := c.fd.pfd.RawControl(f)
	runtime.KeepAlive(c.fd)
	if err != nil {
		err = &OpError{Op: "raw-control", Net: c.fd.net, Source: nil, Addr: c.fd.laddr, Err: err}
	}
	return err
}

func (c *rawConn) Read(f func(uintptr) bool) error {
	if !c.ok() {
		return syscall.EINVAL
	}
	err := c.fd.pfd.RawRead(f)
	runtime.KeepAlive(c.fd)

func (c *IPConn) SyscallConn() (syscall.RawConn, error) {
	if !c.ok() {
		return nil, syscall.EINVAL
	}
	return newRawConn(c.fd), nil
}

// ReadFromIP acts like ReadFrom but returns an IPAddr.
func (c *IPConn) ReadFromIP(b []byte) (int, *IPAddr, error) {
	if !c.ok() {
		return 0, nil, syscall.EINVAL
	}
	n, addr, err := c.readFrom(b)
	if err != nil {

	case AF_INET:
		if len(b) < SizeofSockaddrInet4 {
			return nil, EINVAL
		}
		rsa := (*RawSockaddrAny)(unsafe.Pointer(&b[0]))
		return anyToSockaddr(rsa)
	case AF_INET6:
		if len(b) < SizeofSockaddrInet6 {
			return nil, EINVAL
		}
		rsa := (*RawSockaddrAny)(unsafe.Pointer(&b[0]))
		return anyToSockaddr(rsa)
	default:
		return nil, EINVAL
	}
}

const (

func (c *TCPConn) SyscallConn() (syscall.RawConn, error) {
	if !c.ok() {
		return nil, syscall.EINVAL
	}
	return newRawConn(c.fd), nil
}

// ReadFrom implements the [io.ReaderFrom] ReadFrom method.
func (c *TCPConn) ReadFrom(r io.Reader) (int64, error) {
	if !c.ok() {
		return 0, syscall.EINVAL
	}
	n, err := c.readFrom(r)
	if err != nil && err != io.EOF {

func (p *Process) release() error {
	// Drop the Process' reference and mark handle unusable for
	// future calls.
	//
	// The API on Windows expects EINVAL if Release is called multiple
	// times.
	if old := p.handlePersistentRelease(statusReleased); old == statusReleased {
		return syscall.EINVAL
	}

	// no need for a finalizer anymore
	runtime.SetFinalizer(p, nil)
	return nil
}

func (p *Process) closeHandle() {

		if n > 0 {
			pos += int64(n)
			written += int64(n)
			remain -= int64(n)
		}
		if err == syscall.EINTR {
			continue
		}
		// This includes syscall.ENOSYS (no kernel
		// support) and syscall.EINVAL (fd types which
		// don't implement sendfile), and other errors.
		// We should end the loop when there is no error
		// returned from sendfile(2) or it is not a retryable error.
		if err != syscall.EAGAIN {
			break
		}

	}
	fd.Close()
	return nil, syscall.EINVAL
}

func fileListener(f *os.File) (Listener, error) {
	fd, err := newFileFD(f)
	if err != nil {
		return nil, err
	}
	switch laddr := fd.laddr.(type) {
	case *TCPAddr:
		return &TCPListener{fd: fd}, nil
	case *UnixAddr:
		return &UnixListener{fd: fd, path: laddr.Name, unlink: false}, nil
	}
	fd.Close()
	return nil, syscall.EINVAL
}

// integer array of open file descriptors from another process.
func ParseUnixRights(m *SocketControlMessage) ([]int, error) {
	if m.Header.Level != SOL_SOCKET {
		return nil, EINVAL
	}
	if m.Header.Type != SCM_RIGHTS {
		return nil, EINVAL
	}
	fds := make([]int, len(m.Data)>>2)
	for i, j := 0, 0; i < len(m.Data); i += 4 {
		fds[j] = int(*(*int32)(unsafe.Pointer(&m.Data[i])))
		j++
	}
	return fds, nil

		if n > 0 {
			written += int64(n)
			remain -= int64(n)
			continue
		} else if err != syscall.EAGAIN && err != syscall.EINTR {
			// This includes syscall.ENOSYS (no kernel
			// support) and syscall.EINVAL (fd types which
			// don't implement sendfile), and other errors.
			// We should end the loop when there is no error
			// returned from sendfile(2) or it is not a retryable error.
			break
		}