SV*
uppercase_utf8_2(SV* sv)
PREINIT:
    size_t len;
    char* s;
    char* upperstring; //uint8_t also
    SV* aresult;

   size_t upperlength;
CODE:
    s = SvPVbyte(sv, len);  //strings from my editor (locale?) are already utf8 encoded
    upperstring = u8_toupper (s, len, NULL, NULL,NULL, &upperlength);
    upperlength = u8_strlen(upperstring);
    aresult = newSVpv(upperstring,upperlength);
    free(upperstring);
	RETVAL = aresult;
OUTPUT:
	RETVAL