1  #include <getopt.h>
       2  #include <stdio.h>
       3  #include <string.h>
       4  #include <unistd.h>
       5  
       6  int
       7  main (int argc, char **argv)
       8  {
       9    static const struct option options[] =
      10      {
      11        {"required", required_argument, NULL, 'r'},
      12        {"optional", optional_argument, NULL, 'o'},
      13        {"none",     no_argument,       NULL, 'n'},
      14        {"color",    no_argument,       NULL, 'C'},
      15        {"colour",   no_argument,       NULL, 'C'},
      16        {NULL,       0,                 NULL, 0 }
      17      };
      18  
      19    int aflag = 0;
      20    int bflag = 0;
      21    char *cvalue = NULL;
      22    int Cflag = 0;
      23    int nflag = 0;
      24    int index;
      25    int c;
      26    int result = 0;
      27  
      28    while ((c = getopt_long (argc, argv, "abc:", options, NULL)) >= 0)
      29      switch (c)
      30        {
      31        case 'a':
      32  	aflag = 1;
      33  	break;
      34        case 'b':
      35  	bflag = 1;
      36  	break;
      37        case 'c':
      38  	cvalue = optarg;
      39  	break;
      40        case 'C':
      41  	++Cflag;
      42  	break;
      43        case '?':
      44  	fputs ("Unknown option.\n", stderr);
      45  	return 1;
      46        default:
      47  	fprintf (stderr, "This should never happen!\n");
      48  	return 1;
      49  
      50        case 'r':
      51  	printf ("--required %s\n", optarg);
      52  	result |= strcmp (optarg, "foobar") != 0;
      53  	break;
      54        case 'o':
      55  	printf ("--optional %s\n", optarg);
      56  	result |= optarg == NULL || strcmp (optarg, "bazbug") != 0;
      57  	break;
      58        case 'n':
      59  	puts ("--none");
      60  	nflag = 1;
      61  	break;
      62        }
      63  
      64    printf ("aflag = %d, bflag = %d, cvalue = %s, Cflags = %d, nflag = %d\n",
      65  	  aflag, bflag, cvalue, Cflag, nflag);
      66  
      67    result |= (aflag != 1 || bflag != 1 || cvalue == NULL
      68  	     || strcmp (cvalue, "foobar") != 0 || Cflag != 3 || nflag != 1);
      69  
      70    for (index = optind; index < argc; index++)
      71      printf ("Non-option argument %s\n", argv[index]);
      72  
      73    result |= optind + 1 != argc || strcmp (argv[optind], "random") != 0;
      74  
      75    return result;
      76  }