// the case where a runaway process grabs the exclusive lock and
		// blocks this call indefinitely.
		// https://man7.org/linux/man-pages/man2/fcntl.2.html
		lock := syscall.Flock_t{Type: syscall.F_WRLCK}
		if err = syscall.FcntlFlock(f.Fd(), syscall.F_SETLK, &lock); err == nil {
			break
		}
		time.Sleep(200 * time.Millisecond)
		if time.Now().After(deadline) {

type Dirent struct {
	Ino       uint64
	Off       int64
	Reclen    uint16
	Type      uint8
	Name      [256]int8
	Pad_cgo_0 [5]byte
}

type Fsid struct {
	X__val [2]int32
}

type Flock_t struct {
	Type      int16
	Whence    int16
	Pad_cgo_0 [4]byte
	Start     int64
	Len       int64
	Pid       int32
	Pad_cgo_1 [4]byte
}

type RawSockaddrInet4 struct {
	Family uint16

func FcntlInt(fd uintptr, cmd, arg int) (int, error) {
	return fcntl(int(fd), cmd, arg)
}

// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.
func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
	_, err := fcntlPtr(int(fd), cmd, unsafe.Pointer(lk))
	return err
}

//sys	ppoll(fds *PollFd, nfds int, timeout *Timespec, sigmask *Sigset_t) (n int, err error)

//sys	FcntlInt(fd uintptr, cmd int, arg int) (r int,err error) = fcntl

// FcntlFlock performs a fcntl syscall for the F_GETLK, F_SETLK or F_SETLKW command.
//sys	FcntlFlock(fd uintptr, cmd int, lk *Flock_t) (err error) = fcntl

//sys	fcntl(fd int, cmd int, arg int) (val int, err error)

//sys	fsyncRange(fd int, how int, start int64, length int64) (err error) = fsync_range

func Fsync(fd int) error {

}

//sys	fcntl(fd int, cmd int, arg int) (val int, err error)

// FcntlFlock performs a fcntl syscall for the [F_GETLK], [F_SETLK] or [F_SETLKW] command.
func FcntlFlock(fd uintptr, cmd int, lk *Flock_t) error {
	_, _, e1 := sysvicall6(uintptr(unsafe.Pointer(&libc_fcntl)), 3, uintptr(fd), uintptr(cmd), uintptr(unsafe.Pointer(lk)), 0, 0, 0)
	if e1 != 0 {
		return e1
	}
	return nil
}

pkg syscall (freebsd-arm), type Flock_t struct
pkg syscall (freebsd-arm), type Flock_t struct, Len int64
pkg syscall (freebsd-arm), type Flock_t struct, Pid int32
pkg syscall (freebsd-arm), type Flock_t struct, Start int64
pkg syscall (freebsd-arm), type Flock_t struct, Sysid int32
pkg syscall (freebsd-arm), type Flock_t struct, Type int16
pkg syscall (freebsd-arm), type Flock_t struct, Whence int16

pkg syscall (freebsd-arm64), type Flock_t struct
pkg syscall (freebsd-arm64), type Flock_t struct, Len int64
pkg syscall (freebsd-arm64), type Flock_t struct, Pad_cgo_0 [4]uint8
pkg syscall (freebsd-arm64), type Flock_t struct, Pid int32
pkg syscall (freebsd-arm64), type Flock_t struct, Start int64
pkg syscall (freebsd-arm64), type Flock_t struct, Sysid int32

pkg syscall (netbsd-arm64-cgo), type Flock_t struct
pkg syscall (netbsd-arm64-cgo), type Flock_t struct, Len int64
pkg syscall (netbsd-arm64-cgo), type Flock_t struct, Pid int32
pkg syscall (netbsd-arm64-cgo), type Flock_t struct, Start int64
pkg syscall (netbsd-arm64-cgo), type Flock_t struct, Type int16
pkg syscall (netbsd-arm64-cgo), type Flock_t struct, Whence int16
pkg syscall (netbsd-arm64-cgo), type Fsid struct

pkg syscall (freebsd-riscv64), type Flock_t struct #53466
pkg syscall (freebsd-riscv64), type Flock_t struct, Len int64 #53466
pkg syscall (freebsd-riscv64), type Flock_t struct, Pad_cgo_0 [4]uint8 #53466
pkg syscall (freebsd-riscv64), type Flock_t struct, Pid int32 #53466
pkg syscall (freebsd-riscv64), type Flock_t struct, Start int64 #53466
pkg syscall (freebsd-riscv64), type Flock_t struct, Sysid int32 #53466

pkg syscall (darwin-arm64), type Flock_t struct
pkg syscall (darwin-arm64), type Flock_t struct, Len int64
pkg syscall (darwin-arm64), type Flock_t struct, Pid int32
pkg syscall (darwin-arm64), type Flock_t struct, Start int64
pkg syscall (darwin-arm64), type Flock_t struct, Type int16
pkg syscall (darwin-arm64), type Flock_t struct, Whence int16
pkg syscall (darwin-arm64), type Fsid struct