If the callback’s return value is H5O_MCDT_SEARCH_ERROR, H5O_COPY will abort and the destination file may be left in an inconsistent or corrupted state.

Failure Modes:

H5O_mcdtMCDT_searchSEARCH_cbCB_t T failure modes are dependent on the implementation of the callback function.

This example defines a callback function in the object copy property list to discontinue the global search if a matching committed datatype cannot be found among the suggested paths.

/* The user-defined callback function */
static H5O_mcdt_search_ret_t
mcdt_search_cb(void *_udata)
{
    H5O_mcdt_search_ret_t action = *((H5O_mcdt_search_ret_t *)_udata);

    return(action);
}

int main(void) {
    hid_t ocpypl_id = H5Pcreate(H5P_OBJECT_COPY);

    /* Enable the merging committed datatype feature. */
    H5Pset_copy_object(ocpypl_id, H5O_COPY_MERGE_COMMITTED_DTYPE_FLAG);

    /* Add the path to search for a matching committed datatype. */
    H5Padd_merge_committed_dtype_path(ocpypl_id, "/group/committed_dtypeA");

    /*
     * Set the callback function to discontinue the global search
     * if H5Ocopy cannot find a matching committed datatype from the
     * above suggested path.
     */
    action = H5O_MCDT_SEARCH_STOP;
    H5Pset_mcdt_search_cb(ocpypl_id, mcdt_search_cb, &action);

    /* Do the copy. */
    H5Ocopy(...ocpypl_id...);
    ...
    ...
}