def info(self):
        """Retrieve info about the attribute : name, data type and
        number of values.

        Args::

          no argument

        Returns::

          3-element tuple holding:

          - attribute name
          - attribute data type (see constants SDC.xxx)
          - number of values in the attribute; for a string-valued
            attribute (data type SDC.CHAR8), the number of values
            corresponds to the string length


        C library equivalent : SDattrinfo
                                                       """
        if self._index is None:
            try:
                self._index = self._obj.findattr(self._name)
            except HDF4Error:
                raise HDF4Error("info: cannot convert name to index")
        status, self._name, data_type, n_values = \
                              _C.SDattrinfo(self._obj._id, self._index)
        _checkErr('info', status, 'illegal attribute index')
        return self._name, data_type, n_values