guile/lib/hard-locale.c

/* hard-locale.c -- Determine whether a locale is hard.

   Copyright (C) 1997-1999, 2002-2004, 2006-2007, 2009-2023 Free Software
   Foundation, Inc.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file 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 Lesser General Public License for more details.

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

#include <config.h>

#include "hard-locale.h"

#include <locale.h>
#include <stdlib.h>
#include <string.h>

bool
hard_locale (int category)
{
  char locale[SETLOCALE_NULL_MAX];

  if (setlocale_null_r (category, locale, sizeof (locale)))
    return false;

  if (!(strcmp (locale, "C") == 0 || strcmp (locale, "POSIX") == 0))
    return true;

#if defined __ANDROID__
  /* On Android 5.0 or newer, it is possible to set a locale that has the same
     name as the "C" locale but in fact uses UTF-8 encoding.  Cf. test case 2 in
     <https://lists.gnu.org/archive/html/bug-gnulib/2023-01/msg00141.html>.  */
  if (MB_CUR_MAX > 1)
    return true;
#endif

  return false;
}