cns_big5_comp
ptr = (table_t*) bsearch(&key, cns_big5_tab1, MAX_CNS1_NUM, sizeof(table_t), cns_big5_comp);
ptr = (table_t*) bsearch(&key, cns_big5_tab2, MAX_CNS2_NUM, sizeof(table_t), cns_big5_comp);