/*
 * Copyright (c) 2001-2002 The Trustees of Indiana University.  
 *                         All rights reserved.
 * Copyright (c) 1998-2001 University of Notre Dame. 
 *                         All rights reserved.
 * Copyright (c) 1994-1998 The Ohio State University.  
 *                         All rights reserved.
 * 
 * This file is part of the LAM/MPI software package.  For license
 * information, see the LICENSE file in the top level directory of the
 * LAM/MPI source distribution.
 * 
 * $HEADER$
 *
 * $Id: spawn.c,v 1.12 2002/10/09 20:55:48 brbarret Exp $
 *
 * Program to test MPI_Comm_spawn with simple arguments.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <mpi.h>


static void do_parent(char *cmd);
static void do_target(MPI_Comm parent_inter);

int 
main(int argc, char *argv[])
{
  MPI_Comm parent;
 
  MPI_Init(&argc, &argv);

  /* Check to see if we *were* spawned -- because this is a test, we
     can only assume the existence of this one executable.  Hence, we
     both mpirun it and spawn it. */

  parent = MPI_COMM_NULL;
  MPI_Comm_get_parent(&parent);
  if (parent != MPI_COMM_NULL) {
    do_target(parent);
    printf("Target (pid %d) finished\n", getpid());
  } else {
    do_parent(argv[0]);
    printf("Parent (pid %d) finished\n", getpid());
  }

  /* All done */

  MPI_Finalize();
  printf("Process %d finished\n", getpid());
  return 0;
}


static void
do_parent(char *cmd)
{
  int errcode;
  int bar;
  MPI_Comm child_inter;

  /* Now try the spawn if it's found anywhere */

  MPI_Comm_spawn(cmd, MPI_ARGV_NULL, 1, MPI_INFO_NULL, 0,
                 MPI_COMM_SELF, &child_inter, &errcode); 

  bar = 17;
  MPI_Send(&bar, 1, MPI_INT, 0, 1, child_inter);
}


static void
do_target(MPI_Comm parent)
{
  int foo;

  /* Insert arbitrary delay to ensure that the parent is dead */
  sleep(5);
  MPI_Recv(&foo, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, parent,
           MPI_STATUS_IGNORE);
  printf("Target got value: %d\n", foo);
}