message_string_size+=sprintf(&message_string[message_string_size],"\n\tNACK SN %04d SO START %05d SO END %05d",pdu_info_pP->nack_list[num_nack].nack_sn,
pdu_info_pP->nack_list[num_nack].so_start,
pdu_info_pP->nack_list[num_nack].so_end);
}else{
message_string_size+=sprintf(&message_string[message_string_size],"\n\tNACK SN %04d",pdu_info_pP->nack_list[num_nack].nack_sn);