1 files changed, 54 insertions, 0 deletions
diff --git a/lib/posixver.c b/lib/posixver.c
new file mode 100644
index 0000000..054c95d
--- /dev/null
+++ b/lib/posixver.c
@@ -0,0 +1,54 @@
+/* Which POSIX version to conform to, for utilities.
+
+   Copyright (C) 2002-2006, 2009-2020 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/>.  */
+
+/* Written by Paul Eggert.  */
+
+#include <config.h>
+
+#include "posixver.h"
+
+#include <limits.h>
+#include <stdlib.h>
+
+#include <unistd.h>
+#ifndef _POSIX2_VERSION
+# define _POSIX2_VERSION 0
+#endif
+
+#ifndef DEFAULT_POSIX2_VERSION
+# define DEFAULT_POSIX2_VERSION _POSIX2_VERSION
+#endif
+
+/* The POSIX version that utilities should conform to.  The default is
+   specified by the system.  */
+
+int
+posix2_version (void)
+{
+  long int v = DEFAULT_POSIX2_VERSION;
+  char const *s = getenv ("_POSIX2_VERSION");
+
+  if (s && *s)
+    {
+      char *e;
+      long int i = strtol (s, &e, 10);
+      if (! *e)
+        v = i;
+    }
+
+  return v < INT_MIN ? INT_MIN : v < INT_MAX ? v : INT_MAX;
+}