if(NULL == (dt_mem = H5T_copy(dt_src, H5T_COPY_TRANSIENT)))
            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTINIT, FAIL, "unable to copy")
        if((tid_mem = H5I_register(H5I_DATATYPE, dt_mem, FALSE)) < 0) {
            (void)H5T_close_real(dt_mem);
            HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "unable to register memory datatype")
        } /* end if */
        /* create variable-length datatype at the destinaton file */
        if(NULL == (dt_dst = H5T_copy(dt_src, H5T_COPY_TRANSIENT)))
            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "unable to copy")
        if(H5T_set_loc(dt_dst, f_dst, H5T_LOC_DISK) < 0) {
        if(H5T_set_loc(dt_dst, H5F_VOL_OBJ(f_dst), H5T_LOC_DISK) < 0) {
            (void)H5T_close_real(dt_dst);
            HGOTO_ERROR(H5E_DATASET, H5E_CANTINIT, FAIL, "cannot mark datatype on disk")
        } /* end if */
        if((tid_dst = H5I_register(H5I_DATATYPE, dt_dst, FALSE)) < 0) {
            (void)H5T_close_real(dt_dst);
            HGOTO_ERROR(H5E_DATASET, H5E_CANTREGISTER, FAIL, "unable to register destination file datatype")
        } /* end if */
        /* Set up the conversion functions */
        if(NULL == (tpath_src_mem = H5T_path_find(dt_src, dt_mem)))