In C, getopt_long does not parse the optional arguments to command line parameters parameters.

When I run the program, the optional argument is not recognized like the example run below.

    $ ./respond --praise John
    Kudos to John
    $ ./respond --blame John
    You suck !
    $ ./respond --blame
    You suck !

Here is the test code.

    #include &lt;stdio.h&gt;
    #include &lt;getopt.h&gt;
    
    int main(int argc, char ** argv )
    {
        int getopt_ret, option_index;
        static struct option long_options[] = {
                   {&quot;praise&quot;,  required_argument, 0, &#39;p&#39;},
                   {&quot;blame&quot;,  optional_argument, 0, &#39;b&#39;},
                   {0, 0, 0, 0}       };
        while (1) {
            getopt_ret = getopt_long( argc, argv, &quot;p:b::&quot;,
                                      long_options,  &amp;option_index);
            if (getopt_ret == -1) break;
    
            switch(getopt_ret)
            {
                case 0: break;
                case &#39;p&#39;:
                    printf(&quot;Kudos to %s\n&quot;, optarg); break;
                case &#39;b&#39;:
                    printf(&quot;You suck &quot;);
                    if (optarg)
                        printf (&quot;, %s!\n&quot;, optarg);
                    else
                        printf (&quot;!\n&quot;, optarg);
                    break;
                case &#39;?&#39;:
                    printf(&quot;Unknown option\n&quot;); break;
            }
        } 
        return 0;
    }

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getopt does not parse optional arguments to parameters