//sys	Fadvise(fd int, offset int64, length int64, advice int) (err error) = SYS_FADVISE64
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Fstat(fd int, stat *Stat_t) (err error)
//sys	Fstatat(dirfd int, path string, stat *Stat_t, flags int) (err error) = SYS_NEWFSTATAT
//sys	Fstatfs(fd int, buf *Statfs_t) (err error)
//sys	Ftruncate(fd int, length int64) (err error)
//sysnb	Getegid() (egid int)

		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 {
		return &OpError{Op: "close", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	return nil
}

	return n, err
}

//sys	writev(fd int, iovs []Iovec) (n int, err error)

func Writev(fd int, iovs [][]byte) (n int, err error) {
	iovecs := bytes2iovec(iovs)
	n, err = writev(fd, iovecs)
	return n, err
}

//sys	pwritev(fd int, iovs []Iovec, off int64) (n int, err error)

func Pwritev(fd int, iovs [][]byte, off int64) (n int, err error) {
	iovecs := bytes2iovec(iovs)
	n, err = pwritev(fd, iovecs, off)

	return int(n)
}

func Read(fd int, p []byte) (n int, err error) {
	return Pread(fd, p, -1)
}

func Write(fd int, p []byte) (n int, err error) {
	return Pwrite(fd, p, -1)
}

var ioSync int64

//sys	fd2path(fd int, buf []byte) (err error)

func Fd2path(fd int) (path string, err error) {
	var buf [512]byte

	e := fd2path(fd, buf[:])
	if e != nil {
		return "", e
	}

	SYS_MKFIFOAT       = 319 // { int sys_mkfifoat(int fd, const char *path, mode_t mode); }
	SYS_MKNODAT        = 320 // { int sys_mknodat(int fd, const char *path, mode_t mode, dev_t dev); }
	SYS_OPENAT         = 321 // { int sys_openat(int fd, const char *path, int flags, ... mode_t mode); }

func (fd *FD) SetsockoptInt(level, name, arg int) error {
	if err := fd.incref(); err != nil {
		return err
	}
	defer fd.decref()
	return syscall.SetsockoptInt(fd.Sysfd, level, name, arg)
}

// SetsockoptInet4Addr wraps the setsockopt network call with an IPv4 address.
func (fd *FD) SetsockoptInet4Addr(level, name int, arg [4]byte) error {
	if err := fd.incref(); err != nil {
		return err
	}

	return getState(fd)
}

// Restore restores the terminal connected to the given file descriptor to a
// previous state.
func Restore(fd int, oldState *State) error {
	return restore(fd, oldState)
}

// GetSize returns the visible dimensions of the given terminal.
//
// These dimensions don't include any scrollback buffer height.
func GetSize(fd int) (width, height int, err error) {
	return getSize(fd)
}

	"runtime"
	"syscall"
)

// Writev wraps the writev system call.
func (fd *FD) Writev(v *[][]byte) (int64, error) {
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	if err := fd.pd.prepareWrite(fd.isFile); err != nil {
		return 0, err
	}

	var iovecs []syscall.Iovec
	if fd.iovecs != nil {
		iovecs = *fd.iovecs
	}
	// TODO: read from sysconf(_SC_IOV_MAX)? The Linux default is

//sys	Chroot(path string) (err error)
//sys	Close(fd int) (err error)
//sys	Dup(fd int) (nfd int, err error)
//sys	Dup2(from int, to int) (err error)
//sys	Fchdir(fd int) (err error)
//sys	Fchflags(fd int, flags int) (err error)
//sys	Fchmod(fd int, mode uint32) (err error)
//sys	Fchown(fd int, uid int, gid int) (err error)
//sys	Flock(fd int, how int) (err error)
//sys	Fpathconf(fd int, name int) (val int, err error)

		}
		if err := setKeepAliveCount(c.fd, config.Count); err != nil {
			return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
		}
	} else if err := setKeepAliveIdleAndIntervalAndCount(c.fd, config.Idle, config.Interval, config.Count); err != nil {
		return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}