H5Aiterate2

herr_t H5Aiterate2(hid_t obj_id,  int  idx_type,  int  order,  hsize_t *  idx,
       H5A_operator2_t op,  void *  op_data)

Iterates over attributes attached to an object.

`obj_id`	Object identifier
`idx_type`	Index type (H5_INDEX)
`order`	Iteration order (H5_ITER_ORDER)
`idx`	Starting position; updated to position where iteration stopped
`op`	Callback function to invoke for each attribute
`op_data`	User data to pass to the callback

The return value of the last callback on success, or negative on failure.