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

/*

Compilation:

mpic++ main.cc

Execution:

mpiexec -n 4 a.out 

Expected output:

Thread 1 got 42 from thread 0
Thread 3 got 42 from thread 0
Thread 2 got 42 from thread 0

*/

int main(void) {
  MPI_Init(nullptr, nullptr);
  int world_rank;
  MPI_Comm_rank(MPI_COMM_WORLD, &world_rank);
  int world_size;
  MPI_Comm_size(MPI_COMM_WORLD, &world_size);

  int number = -1;
  if (world_rank == 0) {
    number = 42;
  }
  MPI_Barrier(MPI_COMM_WORLD);
  MPI_Bcast(&number, 1, MPI_INT, 0, MPI_COMM_WORLD);
  if (world_rank != 0) {
    printf("Thread %d got %d from thread 0\n", world_rank, number);
  }
  MPI_Finalize();
}