i18n_01.c

#include <stdio.h>
#include <string.h>
#include <wchar.h>
#include <locale.h>

#define MYLOCALE "de_DE.UTF-8"

int main (void) {

    struct lconv *locale_ptr;

    wchar_t a = L'a';
    wchar_t a1 = L'ä';
    wchar_t b = L'z';

    wchar_t wrd[] = {a, a1, b, '\0'};

    if (setlocale(LC_ALL, MYLOCALE) == NULL) {
	fprintf(stderr, "Can't set the locale %s. "
            "Check LANG, LC_CTYPE, LC_ALL.\n", MYLOCALE);
        return 1; 
    } 

    locale_ptr = localeconv();

    printf("Currency symbol: %s\n", locale_ptr->currency_symbol);
    printf("%lc\n", a);
    printf("%lc\n", a1);
    printf("%lc\n", b);
    printf("%ls\n", wrd);
    printf("%zu\n", sizeof wrd);
    printf("%zu\n", sizeof a1);
    printf("%zu\n", sizeof b);
    printf("%zu\n", wcslen(wrd));
    printf("%d\n", wcscoll(&a, &a1));
    printf("%d\n", wcscoll(&a1, &b));

    return 0;
}