#include <iostream>
#include <mpi.h>

int main (void)
{

  int rank(0);
  MPI_Init(0, NULL);
  MPI_Comm_size(MPI_COMM_WORLD, &rank);
  std::cout << "Rank: " << rank << std::endl;
  char port_name[MPI_MAX_PORT_NAME];
  MPI_Open_port(MPI_INFO_NULL, port_name);
  char publish_name[1024] = {'t','e','s','t','_','p','o','r','t',''};
  MPI_Publish_name(publish_name, MPI_INFO_NULL, port_name);
  std::cout << "Port: " << publish_name << " (" << port_name << ")" << std::endl;
  MPI_Comm client;
  std::cout << "Wating for Comm..." << std::endl;
  MPI_Comm_accept(port_name, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &client);
  std::cout << "Comm accepted" << std::endl;
  MPI_Comm_free(&client);
  MPI_Unpublish_name(publish_name, MPI_INFO_NULL, port_name);
  MPI_Close_port(port_name);
  MPI_Finalize();
  return 1;

}

#include <iostream>
#include <mpi.h>

int main (void)
{

  int rank(0);
  MPI_Init(0, NULL);
  MPI_Comm_size(MPI_COMM_WORLD, &rank);
  std::cout << "Rank: " << rank << std::endl;
  char port_name[MPI_MAX_PORT_NAME];
  MPI_Open_port(MPI_INFO_NULL, port_name);
  char publish_name[1024] = {'t','e','s','t','_','p','o','r','t',''};
  MPI_Publish_name(publish_name, MPI_INFO_NULL, port_name);
  std::cout << "Port: " << publish_name << " (" << port_name << ")" << std::endl;
  MPI_Comm client;
  std::cout << "Wating for Comm..." << std::endl;
  MPI_Comm_accept(port_name, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &client);
  std::cout << "Comm accepted" << std::endl;
  MPI_Comm_free(&client);
  MPI_Unpublish_name(publish_name, MPI_INFO_NULL, port_name);
  MPI_Close_port(port_name);
  MPI_Finalize();
  return 1;

}

mpic++ mpi_src.cc -o mpi_srv.x
mpirun mpi_srv.x

#include <iostream>
#include <mpi.h>

int main (void)
{

  int rank(0);
  MPI_Init(0, NULL);
  MPI_Comm_size(MPI_COMM_WORLD, &rank);
  std::cout << "Rank: " << rank << std::endl;
  char port_name[MPI_MAX_PORT_NAME];
  char publish_name[1024] = {'t','e','s','t','_','p','o','r','t',''};
  MPI_Lookup_name(publish_name, MPI_INFO_NULL, port_name);
  MPI_Comm client;
  MPI_Comm_connect(port_name, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &client);
  MPI_Comm_disconnect(&client);
  MPI_Finalize();
  return 1;

}

#include <iostream>
#include <mpi.h>

int main (void)
{

  int rank(0);
  MPI_Init(0, NULL);
  MPI_Comm_size(MPI_COMM_WORLD, &rank);
  std::cout << "Rank: " << rank << std::endl;
  char port_name[MPI_MAX_PORT_NAME];
  char publish_name[1024] = {'t','e','s','t','_','p','o','r','t',''};
  MPI_Lookup_name(publish_name, MPI_INFO_NULL, port_name);
  MPI_Comm client;
  MPI_Comm_connect(port_name, MPI_INFO_NULL, 0, MPI_COMM_WORLD, &client);
  MPI_Comm_disconnect(&client);
  MPI_Finalize();
  return 1;

}

mpic++ mpi_client.cc -o mpi_client.x
mpirun mpi_client.x

$ mpirun mpi_server.x
...

$ mpirun mpi_server.x
...

$ mpirun mpi_client.x
...