{-6027: 'GRIDFTP_BAD_INPUT_URL_ERR', -6026: 'GRIDFTP_GFTP_CONN_OUT_OF_RANG_ERR', -6025: 'GRIDFTP_NO_FREE_GFTP_CONN_ERR', -6024: 'GRIDFTP_NO_USER_CERT_ERR', -6023: 'GRIDFTP_NEED_NEW_PROXY_CERTIFICATE', -6022: 'GRIDFTP_OPERATION_NOT_SUPPORT', -6021: 'GRIDFTP_SIZE_DONE_CB_ERR', 0: '', ...