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, 2009-2020 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 #include "exitfail.h"
  33
  34 static struct option const long_options[] =
  35 {
  36   {"help", no_argument, NULL, 'h'},
  37   {"version", no_argument, NULL, 'v'},
  38   {NULL, 0, NULL, 0}
  39 };
  40
  41 /* Process long options --help and --version, but only if argc == 2.
  42    Be careful not to gobble up "--".  */
  43
  44 void
  45 parse_long_options (int argc,
  46                     char **argv,
  47                     const char *command_name,
  48                     const char *package,
  49                     const char *version,
  50                     void (*usage_func) (int),
  51                     /* const char *author1, ...*/ ...)
  52 {
  53   int c;
  54   int saved_opterr;
  55
  56   saved_opterr = opterr;
  57
  58   /* Don't print an error message for unrecognized options.  */
  59   opterr = 0;
  60
  61   if (argc == 2
  62       && (c = getopt_long (argc, argv, "+", long_options, NULL)) != -1)
  63     {
  64       switch (c)
  65         {
  66         case 'h':
  67           (*usage_func) (EXIT_SUCCESS);
  68           break;
  69
  70         case 'v':
  71           {
  72             va_list authors;
  73             va_start (authors, usage_func);
  74             version_etc_va (stdout, command_name, package, version, authors);
  75             exit (EXIT_SUCCESS);
  76           }
  77
  78         default:
  79           /* Don't process any other long-named options.  */
  80           break;
  81         }
  82     }
  83
  84   /* Restore previous value.  */
  85   opterr = saved_opterr;
  86
  87   /* Reset this to zero so that getopt internals get initialized from
  88      the probably-new parameters when/if getopt is called later.  */
  89   optind = 0;
  90 }
  91
  92 /* Process the GNU default long options --help and --version (see also
  93    https://gnu.org/prep/standards/html_node/Command_002dLine-Interfaces.html),
  94    and fail for any other unknown long or short option.
  95    Use with SCAN_ALL=true to scan until "--", or with SCAN_ALL=false to stop
  96    at the first non-option argument (or "--", whichever comes first).  */
  97 void
  98 parse_gnu_standard_options_only (int argc,
  99                                  char **argv,
 100                                  const char *command_name,
 101                                  const char *package,
 102                                  const char *version,
 103                                  bool scan_all,
 104                                  void (*usage_func) (int),
 105                                  /* const char *author1, ...*/ ...)
 106 {
 107   int c;
 108   int saved_opterr = opterr;
 109
 110   /* Print an error message for unrecognized options.  */
 111   opterr = 1;
 112
 113   const char *optstring = scan_all ? "" : "+";
 114
 115   if ((c = getopt_long (argc, argv, optstring, long_options, NULL)) != -1)
 116     {
 117       switch (c)
 118         {
 119         case 'h':
 120           (*usage_func) (EXIT_SUCCESS);
 121           break;
 122
 123         case 'v':
 124           {
 125             va_list authors;
 126             va_start (authors, usage_func);
 127             version_etc_va (stdout, command_name, package, version, authors);
 128             exit (EXIT_SUCCESS);
 129           }
 130
 131         default:
 132           (*usage_func) (exit_failure);
 133           break;
 134         }
 135     }
 136
 137   /* Restore previous value.  */
 138   opterr = saved_opterr;
 139 }