#define _XOPEN_SOURCE
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <wctype.h>
#include <locale.h>

int
main (int argc, char *argv[])
{
    int num_char;
    wchar_t *wstring;

    if (argc > 1)
    {
        setlocale (LC_CTYPE, "");
        num_char = mbstowcs (NULL, argv[1], 0) + 1;
        wstring = malloc ((num_char + 1) * sizeof (wstring[0]));
        mbstowcs (wstring, argv[1], num_char);
        printf ("length on screen of '%s' = %d\n", argv[1], wcswidth (wstring, num_char));
        free (wstring);
    }
}