wind_ucs4utf8
ret = wind_ucs4utf8(uni, unilen, ss, NULL);
ret = wind_ucs4utf8(u, len, str, &len2);
return wind_ucs4utf8(in, in_len, NULL, out_len);
int wind_ucs4utf8(const uint32_t *, size_t, char *, size_t *);