sid=sion_open_rank( ... ,&chunksize, rank, &fileptr, ...)   # non-collective

while((!sion_feof(sid))) {                                  # non-collective
      btoread=sion_bytes_avail_in_block(sid);               # non-collective
      bread=fread(localbuffer,1,btoread,fileptr);     
}             

sion_close(sid);                                            # non-collective