#include <stdio.h>     /* for printf */
       #include <stdlib.h>    /* for exit */
       #include <getopt.h>

       int
       main (int argc, char **argv) {
           int c;
           int digit_optind = 0;

           while (1) {
               int this_option_optind = optind ? optind : 1;
               int option_index = 0;
               static struct option long_options[] = {
                   {"  spam  ", 1, 0, 0},
                   {"eggs  ", 1, 0, 0},
                   {"  cheese", 1, 0, 0},
                   {0, 0, 0, 0}
               };

               c = getopt_long (argc, argv, "",
                        long_options, &option_index);
               if (c == -1)
                   break;

               switch (c) {
               case 0:
                   printf ("option %s", long_options[option_index].name);
                   if (optarg)
                       printf (" with arg %s", optarg);
                   printf ("\n");
                   break;

               case '?':
                   break;

               default:
                   printf ("?? getopt returned character code 0%o ??\n", c);
               }
           }
           exit (0);
       }