lib/long-options.c

   1 /* Utility to accept --help and --version options as unobtrusively as possible.
   2
   3    Copyright (C) 1993-1994, 1998-2000, 2002-2006, 2009-2018 Free Software
   4    Foundation, Inc.
   5
   6    This program is free software: you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  18
  19 /* Written by Jim Meyering.  */
  20
  21 #include <config.h>
  22
  23 /* Specification.  */
  24 #include "long-options.h"
  25
  26 #include <stdarg.h>
  27 #include <stdio.h>
  28 #include <stdlib.h>
  29 #include <getopt.h>
  30
  31 #include "version-etc.h"
  32
  33 static struct option const long_options[] =
  34 {
  35   {"help", no_argument, NULL, 'h'},
  36   {"version", no_argument, NULL, 'v'},
  37   {NULL, 0, NULL, 0}
  38 };
  39
  40 /* Process long options --help and --version, but only if argc == 2.
  41    Be careful not to gobble up "--".  */
  42
  43 void
  44 parse_long_options (int argc,
  45                     char **argv,
  46                     const char *command_name,
  47                     const char *package,
  48                     const char *version,
  49                     void (*usage_func) (int),
  50                     /* const char *author1, ...*/ ...)
  51 {
  52   int c;
  53   int saved_opterr;
  54
  55   saved_opterr = opterr;
  56
  57   /* Don't print an error message for unrecognized options.  */
  58   opterr = 0;
  59
  60   if (argc == 2
  61       && (c = getopt_long (argc, argv, "+", long_options, NULL)) != -1)
  62     {
  63       switch (c)
  64         {
  65         case 'h':
  66           (*usage_func) (EXIT_SUCCESS);
  67           break;
  68
  69         case 'v':
  70           {
  71             va_list authors;
  72             va_start (authors, usage_func);
  73             version_etc_va (stdout, command_name, package, version, authors);
  74             exit (0);
  75           }
  76
  77         default:
  78           /* Don't process any other long-named options.  */
  79           break;
  80         }
  81     }
  82
  83   /* Restore previous value.  */
  84   opterr = saved_opterr;
  85
  86   /* Reset this to zero so that getopt internals get initialized from
  87      the probably-new parameters when/if getopt is called later.  */
  88   optind = 0;
  89 }