#include <stdio.h>
#include <unicase.h>
#include <stdlib.h>
#include <unistr.h>
#include <uninorm.h>
#include <string.h>
#include <unistr.h>
#include <unitypes.h>
void main(){
char* instring = "Hauptstraße 3"; // Works with uint8_t too
size_t length;
uint8_t *result;
size_t input_length;
input_length=strlen(instring); //u8_strlen works too
result = u8_toupper (instring, input_length, NULL, UNINORM_NFC, NULL, &length);