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

/*

 *  (C) 2001 by Argonne National Laboratory.

 *      See COPYRIGHT in top-level directory.

 */

#include "mpi.h"

#include <stdio.h>

#include <string.h>

#include <stdlib.h>

/* tests MPI_MODE_EXCL */

static void handle_error(int errcode, const char *str)

{

    char msg[MPI_MAX_ERROR_STRING];

    int resultlen;

    MPI_Error_string(errcode, msg, &resultlen);

    fprintf(stderr, "%s: %s\n", str, msg);

}

int main(int argc, char **argv)

{

    MPI_File fh;

    int rank, len, err, i;

    int errs = 0, toterrs;

    char *filename;

    MPI_Init(&argc, &argv);

    MPI_Comm_rank(MPI_COMM_WORLD, &rank;;

/* process 0 takes the file name as a command-line argument and

   broadcasts it to other processes */

    if (!rank) {

        i = 1;

        while ((i < argc) && strcmp("-fname", *argv)) {

            i++;

            argv++;

        }

        if (i >= argc) {

            fprintf(stderr, "\n*#  Usage: excl -fname filename\n\n");

            MPI_Abort(MPI_COMM_WORLD, 1);

        }

        argv++;

        len = strlen(*argv);

        filename = (char *) malloc(len + 10);

        strcpy(filename, *argv);

        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);

        MPI_Bcast(filename, len + 10, MPI_CHAR, 0, MPI_COMM_WORLD);

    } else {

        MPI_Bcast(&len, 1, MPI_INT, 0, MPI_COMM_WORLD);

        filename = (char *) malloc(len + 10);

        MPI_Bcast(filename, len + 10, MPI_CHAR, 0, MPI_COMM_WORLD);

    }

    if (!rank)

        MPI_File_delete(filename, MPI_INFO_NULL);

    MPI_Barrier(MPI_COMM_WORLD);

    /* this open should succeed */

    err = MPI_File_open(MPI_COMM_WORLD, filename,

                        MPI_MODE_CREATE | MPI_MODE_EXCL | MPI_MODE_RDWR, MPI_INFO_NULL, &fh;;

    if (err != MPI_SUCCESS) {

        handle_error(err, "MPI_File_open");

        errs++;

        fprintf(stderr, "Process %d: open failed when it should have succeeded\n", rank);

    } else

        MPI_File_close(&fh;;

    MPI_Barrier(MPI_COMM_WORLD);

    /* this open should fail */

    err = MPI_File_open(MPI_COMM_WORLD, filename,

                        MPI_MODE_CREATE | MPI_MODE_EXCL | MPI_MODE_RDWR, MPI_INFO_NULL, &fh;;

    if (err == MPI_SUCCESS) {

        errs++;

        fprintf(stderr, "Process %d: open succeeded when it should have failed\n", rank);

        MPI_File_close(&fh;;

    }

    MPI_Allreduce(&errs, &toterrs, 1, MPI_INT, MPI_SUM, MPI_COMM_WORLD);

    if (rank == 0) {

        if (toterrs > 0) {

            fprintf(stderr, "Found %d errors\n", toterrs);

        } else {

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

        }

    }

    free(filename);

    MPI_Finalize();

    return 0;

}