MPI_Irecv (buf1, buf_size, MPI_INT,
MPI_ANY_SOURCE, 0, MPI_COMM_WORLD, &req);
printf("Proc 0: Request number - %p\n",req);
MPI_Send (buf0, buf_size, MPI_INT, 1, 0, MPI_COMM_WORLD);
MPI_Irecv (buf1, buf_size, MPI_INT,
MPI_ANY_SOURCE, 0, MPI_COMM_WORLD, &req);
printf("Proc 0: Request number - %p\n",req);
MPI_Send (buf0, buf_size, MPI_INT, 1, 0, MPI_COMM_WORLD);