A digression on echo. - Other *nix-like OSes & POSIX related

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seninha
Long time nixers
Another GNUism that turned out into a meme:
GNU true(1), an utility that is supposed to return zero (true), can return non-zero (false).
That's because it does way more than return 0.

Compare OpenBSD implementation of true(1) with GNU's.

Code:
/*    $OpenBSD: true.c,v 1.1 2015/11/11 19:05:28 deraadt Exp $    */

/* Public domain - Theo de Raadt */

int
main(int argc, char *argv[])
{
    return (0);
}

Code:
/* Exit with a status code indicating success.
   Copyright (C) 1999-2020 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

#include <config.h>
#include <stdio.h>
#include <sys/types.h>
#include "system.h"

/* Act like "true" by default; false.c overrides this.  */
#ifndef EXIT_STATUS
# define EXIT_STATUS EXIT_SUCCESS
#endif

#if EXIT_STATUS == EXIT_SUCCESS
# define PROGRAM_NAME "true"
#else
# define PROGRAM_NAME "false"
#endif

#define AUTHORS proper_name ("Jim Meyering")

void
usage (int status)
{
  printf (_("\
Usage: %s [ignored command line arguments]\n\
  or:  %s OPTION\n\
"),
          program_name, program_name);
  printf ("%s\n\n",
          _(EXIT_STATUS == EXIT_SUCCESS
            ? N_("Exit with a status code indicating success.")
            : N_("Exit with a status code indicating failure.")));
  fputs (HELP_OPTION_DESCRIPTION, stdout);
  fputs (VERSION_OPTION_DESCRIPTION, stdout);
  printf (USAGE_BUILTIN_WARNING, PROGRAM_NAME);
  emit_ancillary_info (PROGRAM_NAME);
  exit (status);
}

int
main (int argc, char **argv)
{
  /* Recognize --help or --version only if it's the only command-line
     argument.  */
  if (argc == 2)
    {
      initialize_main (&argc, &argv);
      set_program_name (argv[0]);
      setlocale (LC_ALL, "");
      bindtextdomain (PACKAGE, LOCALEDIR);
      textdomain (PACKAGE);

      /* Note true(1) will return EXIT_FAILURE in the
         edge case where writes fail with GNU specific options.  */
      atexit (close_stdout);

      if (STREQ (argv[1], "--help"))
        usage (EXIT_STATUS);

      if (STREQ (argv[1], "--version"))
        version_etc (stdout, PROGRAM_NAME, PACKAGE_NAME, Version, AUTHORS,
                     (char *) NULL);
    }

  return EXIT_STATUS;
}


Messages In This Thread
A digression on echo. - by seninha - 20-04-2020, 10:57 AM
RE: A digression on echo. - by jkl - 20-04-2020, 03:31 PM
RE: A digression on echo. - by z3bra - 20-04-2020, 03:40 PM
RE: A digression on echo. - by seninha - 20-04-2020, 04:29 PM
RE: A digression on echo. - by jkl - 20-04-2020, 04:33 PM
RE: A digression on echo. - by z3bra - 21-04-2020, 05:09 AM
RE: A digression on echo. - by jkl - 21-04-2020, 05:13 AM
RE: A digression on echo. - by twee - 21-04-2020, 05:22 PM
RE: A digression on echo. - by seninha - 28-11-2020, 11:23 AM