1/* Example of Parsing Arguments with getopt.
2 Copyright (C) 1991-2022 Free Software Foundation, Inc.
3
4 This program is free software; you can redistribute it and/or
5 modify it under the terms of the GNU General Public License
6 as published by the Free Software Foundation; either version 2
7 of the License, or (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, see <https://www.gnu.org/licenses/>.
16*/
17
18/*@group*/
19#include <ctype.h>
20#include <stdio.h>
21#include <stdlib.h>
22#include <unistd.h>
23
24int
25main (int argc, char **argv)
26{
27 int aflag = 0;
28 int bflag = 0;
29 char *cvalue = NULL;
30 int index;
31 int c;
32
33 opterr = 0;
34/*@end group*/
35
36/*@group*/
37 while ((c = getopt (argc: argc, argv: argv, shortopts: "abc:")) != -1)
38 switch (c)
39 {
40 case 'a':
41 aflag = 1;
42 break;
43 case 'b':
44 bflag = 1;
45 break;
46 case 'c':
47 cvalue = optarg;
48 break;
49 case '?':
50 if (optopt == 'c')
51 fprintf (stderr, "Option -%c requires an argument.\n", optopt);
52 else if (isprint (optopt))
53 fprintf (stderr, "Unknown option `-%c'.\n", optopt);
54 else
55 fprintf (stderr,
56 "Unknown option character `\\x%x'.\n",
57 optopt);
58 return 1;
59 default:
60 abort ();
61 }
62/*@end group*/
63
64/*@group*/
65 printf (format: "aflag = %d, bflag = %d, cvalue = %s\n",
66 aflag, bflag, cvalue);
67
68 for (index = optind; index < argc; index++)
69 printf (format: "Non-option argument %s\n", argv[index]);
70 return 0;
71}
72/*@end group*/
73

source code of glibc/manual/examples/testopt.c