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Example of Parsing Long Options

#include <stdio.h>

/* Flag set by `--verbose'. */
static int verbose_flag;

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

  while (1)
    {
      static struct option long_options[] =
        {
          /* These options set a flag. */
          {"verbose", 0, &verbose_flag, 1},
          {"brief", 0, &verbose_flag, 0},
          /* These options don't set a flag.
             We distinguish them by their indices. */
          {"add", 1, 0, 0},
          {"append", 0, 0, 0},
          {"delete", 1, 0, 0},
          {"create", 0, 0, 0},
          {"file", 1, 0, 0},
          {0, 0, 0, 0}
        };
      /* getopt_long stores the option index here. */
      int option_index = 0;

      c = getopt_long (argc, argv, "abc:d:",
                       long_options, &option_index);

      /* Detect the end of the options. */
      if (c == -1)
        break;

      switch (c)
        {
        case 0:
          /* If this option set a flag, do nothing else now. */
          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 '?':
          /* getopt_long already printed an error message. */
          break;

        default:
          abort ();
        }
    }

  /* Instead of reporting `--verbose'
     and `--brief' as they are encountered,
     we report the final status resulting from them. */
  if (verbose_flag)
    puts ("verbose flag is set");

  /* Print any remaining command line arguments (not options). */
  if (optind < argc)
    {
      printf ("non-option ARGV-elements: ");
      while (optind < argc)
        printf ("%s ", argv[optind++]);
      putchar ('\n');
    }

  exit (0);
}

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