if pathErr, ok := err.(*os.PathError); ok {
							if errno, pok := pathErr.Err.(syscall.Errno); pok {
								resultErrno = uintptr(errno)
							}
						}
						if pathErr, ok := testCase.expectedErr.(*os.PathError); ok {
							if errno, pok := pathErr.Err.(syscall.Errno); pok {
								expectErrno = uintptr(errno)
							}
						}

	lockFileExclusiveLock   = 2
	lockFileFailImmediately = 1

	// see https://msdn.microsoft.com/en-us/library/windows/desktop/ms681382(v=vs.85).aspx
	errLockViolation syscall.Errno = 0x21
)

// lockedOpenFile is an internal function.
func lockedOpenFile(path string, flag int, perm os.FileMode, lockType uint32) (*LockedFile, error) {
	f, err := Open(path, flag, perm)
	if err != nil {