py3.py 文件源码

def seekable(self):
        if self._seekable is None:
            try:
                _original_os.lseek(self._fileno, 0, _original_os.SEEK_CUR)
            except IOError as e:
                if get_errno(e) == errno.ESPIPE:
                    self._seekable = False
                else:
                    raise
            else:
                self._seekable = True

        return self._seekable