//printf("%s\n", h5dDatasetname.c_str());
DLong h5d_id;
h5d_id = H5Dopen(h5f_id, h5dDatasetname.c_str());
h5d_id = H5Dopen(h5f_id, h5dDatasetname.c_str(), H5P_DEFAULT);
return new DLongGDL( h5d_id );
}