// IoctlSetInt performs an ioctl operation which sets an integer value
// on fd, using the specified request number.
func IoctlSetInt(fd int, req int, value int) error {
	return ioctl(fd, req, uintptr(value))
}

// IoctlSetWinsize performs an ioctl on fd with a *Winsize argument.
//
// To change fd's window size, the req argument should be TIOCSWINSZ.
func IoctlSetWinsize(fd int, req int, value *Winsize) error {

// Implemented in assembly to avoid allocation.
func seek(fd int, offset int64, whence int) (newoffset int64, err Errno)

func Seek(fd int, offset int64, whence int) (newoffset int64, err error) {
	newoffset, errno := seek(fd, offset, whence)
	if errno != 0 {
		return 0, errno
	}
	return newoffset, nil
}

//sys	accept4(s int, rsa *RawSockaddrAny, addrlen *_Socklen, flags int) (fd int, err error)

// on write calls.
//
//go:nowritebarrierrec
func write(fd uintptr, p unsafe.Pointer, n int32) int32 {
	if !(fd == 1 || fd == 2) {
		// Do an ordinary write.
		return write1(fd, p, n)
	}

	// Write with the playback header.

	// First, lock to avoid interleaving writes.
	lock(&faketimeState.lock)

	// If the current fd doesn't match the fd of the previous write,

//sysnb	socket(domain int, typ int, proto int) (fd int, err error)
//sysnb	socketpair(domain int, typ int, proto int, fd *[2]int32) (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	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)

var fcntl64Syscall uintptr = SYS_FCNTL

func fcntl(fd int, cmd, arg int) (int, error) {
	valptr, _, errno := Syscall(fcntl64Syscall, uintptr(fd), uintptr(cmd), uintptr(arg))
	var err error
	if errno != 0 {
		err = errno
	}
	return int(valptr), err
}

// FcntlInt performs a fcntl syscall on fd with the provided command and argument.
func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
	return fcntl(int(fd), cmd, arg)

import (
	"os"
	"runtime"
	"syscall"
)

func setIPv4MulticastInterface(fd *netFD, ifi *Interface) error {
	ip, err := interfaceToIPv4Addr(ifi)
	if err != nil {
		return os.NewSyscallError("setsockopt", err)
	}
	var a [4]byte
	copy(a[:], ip.To4())
	err = fd.pfd.SetsockoptInet4Addr(syscall.IPPROTO_IP, syscall.IP_MULTICAST_IF, a)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}

	if d == 0 {
		d = defaultTCPKeepAliveInterval
	} else if d < 0 {
		return nil
	}

	// The kernel expects seconds so round to next highest second.
	secs := int(roundDurationUp(d, time.Second))
	err := fd.pfd.SetsockoptInt(syscall.IPPROTO_TCP, syscall.TCP_KEEPINTVL, secs)
	runtime.KeepAlive(fd)
	return wrapSyscallError("setsockopt", err)
}

	if c.fd.isConnected && addr != nil {
		return 0, 0, ErrWriteToConnected
	}
	if !c.fd.isConnected && addr == nil {
		return 0, 0, errMissingAddress
	}
	sa, err := addr.sockaddr(c.fd.family)
	if err != nil {
		return 0, 0, err
	}
	return c.fd.writeMsg(b, oob, sa)
}

func (c *UDPConn) writeMsgAddrPort(b, oob []byte, addr netip.AddrPort) (n, oobn int, err error) {
	if c.fd.isConnected && addr.IsValid() {

//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)

func Fstatat(fd int, path string, stat *Stat_t, flags int) error {
	return fstatat(fd, path, stat, flags)
}

//sys	Fstatfs(fd int, buf *Statfs_t) (err error)
//sys	Ftruncate(fd int, length int64) (err error)