return syscall.EINVAL
	}

	if err := setKeepAlive(c.fd, config.Enable); err != nil {
		return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	if err := setKeepAliveIdle(c.fd, config.Idle); err != nil {
		return &OpError{Op: "set", Net: c.fd.net, Source: c.fd.laddr, Addr: c.fd.raddr, Err: err}
	}
	if err := setKeepAliveInterval(c.fd, config.Interval); err != nil {

}

func IoctlGetRTCTime(fd int) (*RTCTime, error) {
	var value RTCTime
	err := ioctlPtr(fd, RTC_RD_TIME, unsafe.Pointer(&value))
	return &value, err
}

func IoctlSetRTCTime(fd int, value *RTCTime) error {
	return ioctlPtr(fd, RTC_SET_TIME, unsafe.Pointer(value))
}

func IoctlGetRTCWkAlrm(fd int) (*RTCWkAlrm, error) {
	var value RTCWkAlrm
	err := ioctlPtr(fd, RTC_WKALM_RD, unsafe.Pointer(&value))
	return &value, err
}

		if fd[i] == -1 {
			RawSyscall(SYS_CLOSE, uintptr(i), 0, 0)
			continue
		}
		if fd[i] == i {
			// dup2(i, i) won't clear close-on-exec flag on Linux,
			// probably not elsewhere either.
			_, _, err1 = RawSyscall(SYS_FCNTL, uintptr(fd[i]), F_SETFD, 0)
			if err1 != 0 {
				goto childerror
			}
			continue
		}
		// The new fd is created NOT close-on-exec,
		// which is exactly what we want.

//sys	setsockopt(s int, level int, name int, val unsafe.Pointer, vallen uintptr) (err error)
//sysnb	socket(domain int, typ int, proto int) (fd int, err error)
//sysnb	getpeername(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
//sysnb	getsockname(fd int, rsa *RawSockaddrAny, addrlen *_Socklen) (err error)
//sys	recvfrom(fd int, p []byte, flags int, from *RawSockaddrAny, fromlen *_Socklen) (n int, err error)

//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 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)

	"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}
	}

package term

import (
	"golang.org/x/sys/unix"
)

type state struct {
	termios unix.Termios
}

func isTerminal(fd int) bool {
	_, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
	return err == nil
}

func makeRaw(fd int) (*State, error) {
	termios, err := unix.IoctlGetTermios(fd, ioctlReadTermios)
	if err != nil {
		return nil, err
	}

	oldState := State{state{termios: *termios}}