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* example of parallel MPI write into a single file */
#include "mpi.h"
#include <stdio.h>
#define BUFSIZE 100
int main(int argc, char *argv[])
{
/*    int j = 0;
    char hostname[256];
    gethostname(hostname, sizeof(hostname));
    printf("PID %d on %s ready for attach\n", getpid(), hostname);
    fflush(stdout);
    while (0 == j)
        sleep(5);
*/
        int ret, resultlen;
        int i, myrank, buf[BUFSIZE];
        char msg[MPI_MAX_ERROR_STRING];
        MPI_File thefile;
        MPI_Init(&argc, &argv);
        MPI_Comm_rank(MPI_COMM_WORLD, &myrank);
        for (i=0; i<BUFSIZE; i++)
                buf[i] = myrank * BUFSIZE + i;
        ret = MPI_File_open(MPI_COMM_WORLD, "pvfs2:/mnt/pvfs2/mpio/testfile",
                MPI_MODE_CREATE | MPI_MODE_WRONLY,
                MPI_INFO_NULL, &thefile);
        if (ret != MPI_SUCCESS)
        {
                MPI_Error_string(ret, msg, &resultlen);
                fprintf(stderr, "MPI_File_open(): %s\n", msg);
                return(-1);
        } else {
                MPI_File_set_view(thefile, myrank * BUFSIZE * sizeof(int),
                        MPI_INT, MPI_INT, "native", MPI_INFO_NULL);
                MPI_File_write(thefile, buf, BUFSIZE, MPI_INT,
                        MPI_STATUS_IGNORE);
                MPI_File_close(&thefile);
                MPI_Finalize();
                return 0;
        }
}
 
/* Flags de Compilacion de OpenMPI-1.8.1:
./configure --prefix=/home/wilderman/openmpi --with-pvfs2=/usr/local --with-pvfs2-libs=/usr/local
 
OrangeFS-2.8.8 (PVFS 1.8.2)
CFLAGS="-fPIC" ./configure