MPI_Barrier(MPI_COMM_WORLD);
//everyobne reads from it.
- printf("[%d] The value in the shared buffer is: %llu\n", rank, (unsigned long long)*buf);
+ printf("[%d] The value in the shared buffer is: %" PRIu64"\n", rank, *buf);
MPI_Barrier(MPI_COMM_WORLD);