/* -*- Mode: C; c-basic-offset:4 ; indent-tabs-mode:nil ; -*- */

/*

 *

 *  (C) 2014 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include <stdio.h>

#include <stdlib.h>

#include <stdbool.h>

#include <string.h>

#include <unistd.h>

#include "mpi.h"

MPI_Comm comm_all;

void error_handler(MPI_Comm * communicator, int *error_code, ...)

{

    MPI_Comm *new_comm = malloc(sizeof(MPI_Comm));

    MPIX_Comm_revoke(comm_all);

    MPIX_Comm_shrink(comm_all, new_comm);

    MPI_Comm_free(&comm_all);

    comm_all = *new_comm;

}

int main(int argc, char *argv[])

{

    int rank, size, i;

    int sum = 0, val = 1;

    int errs = 0;

    MPI_Errhandler errhandler;

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

    MPI_Comm_size(MPI_COMM_WORLD, &size);

    if (size < 4) {

        fprintf(stderr, "Must run with at least 4 processes.\n");

        MPI_Abort(MPI_COMM_WORLD, 1);

    }

    MPI_Comm_dup(MPI_COMM_WORLD, &comm_all);

    MPI_Comm_create_errhandler(&error_handler, &errhandler);

    MPI_Comm_set_errhandler(comm_all, errhandler);

    for (i = 0; i < 10; ++i) {

        MPI_Comm_size(comm_all, &size);

        sum = 0;

        if (i == 5 && rank == 1) {

            exit(1);

        }

        else if (i != 5) {

            MPI_Allreduce(&val, &sum, 1, MPI_INT, MPI_SUM, comm_all);

            if (sum != size && rank == 0) {

                errs++;

                fprintf(stderr, "Incorrect answer: %d != %d\n", sum, size);

            }

        }

    }

    if (0 == rank && errs) {

        fprintf(stdout, " Found %d errors\n", errs);

    }

    else if (0 == rank) {

        fprintf(stdout, " No errors\n");

    }

    MPI_Comm_free(&comm_all);

    MPI_Errhandler_free(&errhandler);

    MPI_Finalize();

    return 0;

}