gbk_to_utf8
sz = gbk_to_utf8(gb_val, ob, obtail, &ret_val, isgbk4);
sz = gbk_to_utf8(gb_val, ob, obtail, &ret_val, isgbk4);
sz = gbk_to_utf8(gb_val, ob, obtail, &ret_val, B_FALSE);
static int8_t gbk_to_utf8(uint32_t gbk_val, uchar_t *ob, uchar_t *obtail,
sz = gbk_to_utf8(gb_val, ob, obtail, &ret_val, B_FALSE);