lib/posixver.c

   1 /* Which POSIX version to conform to, for utilities.
   2
   3    Copyright (C) 2002-2006, 2009-2020 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Paul Eggert.  */
  19
  20 #include <config.h>
  21
  22 #include "posixver.h"
  23
  24 #include <limits.h>
  25 #include <stdlib.h>
  26
  27 #include <unistd.h>
  28 #ifndef _POSIX2_VERSION
  29 # define _POSIX2_VERSION 0
  30 #endif
  31
  32 #ifndef DEFAULT_POSIX2_VERSION
  33 # define DEFAULT_POSIX2_VERSION _POSIX2_VERSION
  34 #endif
  35
  36 /* The POSIX version that utilities should conform to.  The default is
  37    specified by the system.  */
  38
  39 int
  40 posix2_version (void)
  41 {
  42   long int v = DEFAULT_POSIX2_VERSION;
  43   char const *s = getenv ("_POSIX2_VERSION");
  44
  45   if (s && *s)
  46     {
  47       char *e;
  48       long int i = strtol (s, &e, 10);
  49       if (! *e)
  50         v = i;
  51     }
  52
  53   return v < INT_MIN ? INT_MIN : v < INT_MAX ? v : INT_MAX;
  54 }