code: func (c *linuxConsole) open(flag int) (*os.File, error) {
  	r, e := syscall.Open(c.slavePath, flag, 0)
  	if e != nil {
  		return nil, &os.PathError{
  			Op:   "open",
  			Path: c.slavePath,
  			Err:  e,
  		}
  	}
  	return os.NewFile(uintptr(r), c.slavePath), nil
  }
docs: // open is a clone of os.OpenFile without the O_CLOEXEC used to open the pty slave.