#include <stdlib.h>
#include "mpi.h"
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/types.h>
#include <time.h>
#include <limits.h>

#define SLAVE "mpi_slave"

int main(int argc, char* argv[]){
  int nchild,my_rank;
  int *errcodes;

  MPI_Comm intercomm;
  MPI_Init(&argc, &argv);
  MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);

  if((argc < 2) || ((nchild = atoi(argv[1])) <= 0)){
      if(my_rank == 0){
        fprintf(stderr, "Usage: %s <nchild> %d\n", argv[0], argc);
        MPI_Finalize();
        exit(0);
      }
  }
  errcodes = (int*)calloc(sizeof(int),nchild);

  if(MPI_Comm_spawn(SLAVE, argv, nchild, MPI_INFO_NULL, my_rank, MPI_COMM_WORLD, &intercomm, errcodes) != MPI_SUCCESS)
    fprintf(stderr, "Spawn failed!\n");
  else
    fprintf(stderr, "Spawn of %d children successful\n",nchild);

  MPI_Finalize();
  exit(0);
}