void main(int argc, list argv)
{
    if (argc < 4)
    {
        printf("Argc = ", argc, 
                ": provide string (arg1), offset (arg2) and count (arg3)\n");
        exit(1);
    }

    printf(element(1, argv), ": from ", element(2, argv), " over ", 
            element(3, argv), " chars: ", 
            substr(element(1, argv), (int)element(2, argv), 
                                     (int)element(3, argv)), "\n");

    exit(0);
}