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<h4 class="subsection">25.2.4 Example of Parsing Long Options with <code>getopt_long</code></h4>

<pre class="smallexample">     #include &lt;stdio.h&gt;
     #include &lt;stdlib.h&gt;
     #include &lt;getopt.h&gt;
     
     /* <span class="roman">Flag set by &lsquo;</span><samp><span class="samp">--verbose</span></samp><span class="roman">&rsquo;.</span> */
     static int verbose_flag;
     
     int
     main (argc, argv)
          int argc;
          char **argv;
     {
       int c;
     
       while (1)
         {
           static struct option long_options[] =
             {
               /* <span class="roman">These options set a flag.</span> */
               {"verbose", no_argument,       &amp;verbose_flag, 1},
               {"brief",   no_argument,       &amp;verbose_flag, 0},
               /* <span class="roman">These options don't set a flag.
                  We distinguish them by their indices.</span> */
               {"add",     no_argument,       0, 'a'},
               {"append",  no_argument,       0, 'b'},
               {"delete",  required_argument, 0, 'd'},
               {"create",  required_argument, 0, 'c'},
               {"file",    required_argument, 0, 'f'},
               {0, 0, 0, 0}
             };
           /* <code>getopt_long</code><span class="roman"> stores the option index here.</span> */
           int option_index = 0;
     
           c = getopt_long (argc, argv, "abc:d:f:",
                            long_options, &amp;option_index);
     
           /* <span class="roman">Detect the end of the options.</span> */
           if (c == -1)
             break;
     
           switch (c)
             {
             case 0:
               /* <span class="roman">If this option set a flag, do nothing else now.</span> */
               if (long_options[option_index].flag != 0)
                 break;
               printf ("option %s", long_options[option_index].name);
               if (optarg)
                 printf (" with arg %s", optarg);
               printf ("\n");
               break;
     
             case 'a':
               puts ("option -a\n");
               break;
     
             case 'b':
               puts ("option -b\n");
               break;
     
             case 'c':
               printf ("option -c with value `%s'\n", optarg);
               break;
     
             case 'd':
               printf ("option -d with value `%s'\n", optarg);
               break;
     
             case 'f':
               printf ("option -f with value `%s'\n", optarg);
               break;
     
             case '?':
               /* <code>getopt_long</code><span class="roman"> already printed an error message.</span> */
               break;
     
             default:
               abort ();
             }
         }
     
       /* <span class="roman">Instead of reporting &lsquo;</span><samp><span class="samp">--verbose</span></samp><span class="roman">&rsquo;
          and &lsquo;</span><samp><span class="samp">--brief</span></samp><span class="roman">&rsquo; as they are encountered,
          we report the final status resulting from them.</span> */
       if (verbose_flag)
         puts ("verbose flag is set");
     
       /* <span class="roman">Print any remaining command line arguments (not options).</span> */
       if (optind &lt; argc)
         {
           printf ("non-option ARGV-elements: ");
           while (optind &lt; argc)
             printf ("%s ", argv[optind++]);
           putchar ('\n');
         }
     
       exit (0);
     }
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