get(result_addr, result_count, result_datatype, target_rank,
target_disp, target_count, target_datatype, &req);
if (req != MPI_REQUEST_NULL)
get(result_addr, result_count, result_datatype, target_rank,
target_disp, target_count, target_datatype, &req);
if (req != MPI_REQUEST_NULL)