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/*
* Copyright (C) by Argonne National Laboratory
* See COPYRIGHT in top-level directory
*/
/*
* Test code provided by Guruprasad H. Kora
*/
#include "mpi.h"
#include <stdio.h>
#include <string.h>
int main(int argc, char **argv)
{
int my_rank;
int size;
MPI_Comm parentcomm;
MPI_Comm allcomm;
MPI_Init(&argc, &argv);
MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
MPI_Comm_size(MPI_COMM_WORLD, &size);
MPI_Comm_get_parent(&parentcomm);
if (parentcomm == MPI_COMM_NULL) {
fprintf(stdout, "parentcomm is null\n");
}
MPI_Intercomm_merge(parentcomm, 1, &allcomm);
/* Without the Free of allcomm, the children *must not exit* until the
* parent calls MPI_Finalize. */
MPI_Barrier(allcomm);
/* According to 10.5.4, case 1b in MPI2.2, the children and parent are
* still connected unless MPI_Comm_disconnect is used with allcomm.
* MPI_Comm_free is not sufficient */
MPI_Comm_free(&allcomm);
MPI_Comm_disconnect(&parentcomm);
fprintf(stdout, "%s:%d\n", __FILE__, __LINE__);
fflush(stdout);
MPI_Finalize();
fprintf(stdout, "%d:child exiting.\n", my_rank);
fflush(stdout);
return 0;
}
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