xref: /freebsd/contrib/diff/lib/posixver.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
1 /* Which POSIX version to conform to, for utilities.
2 
3    Copyright (C) 2002, 2003, 2004 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 2, or (at your option)
8    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 along
16    with this program; if not, write to the Free Software Foundation,
17    Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
18 
19 /* Written by Paul Eggert.  */
20 
21 #if HAVE_CONFIG_H
22 # include <config.h>
23 #endif
24 
25 #include "posixver.h"
26 
27 #include <limits.h>
28 #include <stdlib.h>
29 
30 #if HAVE_UNISTD_H
31 # include <unistd.h>
32 #endif
33 #ifndef _POSIX2_VERSION
34 # define _POSIX2_VERSION 0
35 #endif
36 
37 #ifndef DEFAULT_POSIX2_VERSION
38 # define DEFAULT_POSIX2_VERSION _POSIX2_VERSION
39 #endif
40 
41 /* The POSIX version that utilities should conform to.  The default is
42    specified by the system.  */
43 
44 int
45 posix2_version (void)
46 {
47   long int v = DEFAULT_POSIX2_VERSION;
48   char const *s = getenv ("_POSIX2_VERSION");
49 
50   if (s && *s)
51     {
52       char *e;
53       long int i = strtol (s, &e, 10);
54       if (! *e)
55 	v = i;
56     }
57 
58   return v < INT_MIN ? INT_MIN : v < INT_MAX ? v : INT_MAX;
59 }
60