#include <pthread.h>
#include <mpi.h>
#include <stdio.h>

#define NUM_THREADS             2
#define MPI_MSG_TAG_NEW_CONN    0
#define MPI_MSG_TAG_SHUTDOWN    1

char port_name[] = "test_port";

void *thread1(void *threadid)
{
    long tid;
    tid = (long) threadid;
    printf("thread %ld\n", tid);
    do {
        MPI_Comm newComm;
        MPI_Comm_accept(port_name, MPI_INFO_NULL, 0,
                        MPI_COMM_SELF, &newComm);
        printf("Accepted a connection\n");
        int buf = 0;
        MPI_Status status;
        printf("start MPI_recv\n");
        MPI_Recv(&buf, 1, MPI_INT, MPI_ANY_SOURCE, MPI_ANY_TAG, newComm,
                 &status);
        printf("end MPI_recv\n");

        if (status.MPI_TAG == MPI_MSG_TAG_SHUTDOWN) {
            printf("Shutdown\n");
            printf("Disconnect\n");
            break;
        } else
            printf("Unmatched Receive\n");
    } while (1);

    pthread_exit(NULL);
}

void *thread2(void *threadid)
{
    long tid;
    tid = (long) threadid;
    printf("thread %ld\n", tid);

    MPI_Comm newComm;
    MPI_Comm_connect(port_name, MPI_INFO_NULL, 0, MPI_COMM_SELF, &newComm);
    printf("Connect to Self\n");
    int val = 0;
    MPI_Request req;
    printf("start MPI_Send\n");
    MPI_Send(&val, 1, MPI_INT, 0, MPI_MSG_TAG_SHUTDOWN, newComm);
    printf("Successful\n");
    printf("Complete\n");

    pthread_exit(NULL);
}

int main(int argc, char *argv[])
{
    int provided;
    MPI_Init_thread(&argc, &argv, MPI_THREAD_MULTIPLE, &provided);
    MPI_Open_port(MPI_INFO_NULL, port_name);

    pthread_t threads[NUM_THREADS];
    pthread_create(&threads[0], NULL, thread1, (void *) 0);
    pthread_create(&threads[1], NULL, thread2, (void *) 1);
    pthread_exit(NULL);
    MPI_Finalize();
}