1 files changed, 82 insertions, 0 deletions

diff --git a/gl/setlocale_null.h b/gl/setlocale_null.h
new file mode 100644
index 00000000..c740fa0f
--- /dev/null
+++ b/gl/setlocale_null.h
@@ -0,0 +1,82 @@
+/* Query the name of the current global locale.
+   Copyright (C) 2019-2023 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/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2019.  */
+
+#ifndef _SETLOCALE_NULL_H
+#define _SETLOCALE_NULL_H
+
+#include <stddef.h>
+
+#include "arg-nonnull.h"
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
+/* Recommended size of a buffer for a locale name for a single category.
+   On glibc systems, you can have locale names that are relative file names;
+   assume a maximum length 256.
+   In native Windows, in 2018 the longest locale name was of length 58
+   ("FYRO Macedonian_Former Yugoslav Republic of Macedonia.1251").  */
+#define SETLOCALE_NULL_MAX (256+1)
+
+/* Recommended size of a buffer for a locale name with all categories.
+   On glibc systems, you can have locale names that are relative file names;
+   assume maximum length 256 for each.  There are 12 categories; so, the
+   maximum total length is 148+12*256.
+   In native Windows, there are 5 categories, and the maximum total length is
+   55+5*58.  */
+#define SETLOCALE_NULL_ALL_MAX (148+12*256+1)
+
+/* setlocale_null_r (CATEGORY, BUF, BUFSIZE) is like setlocale (CATEGORY, NULL),
+   except that
+     - it is guaranteed to be multithread-safe,
+     - it returns the resulting locale category name or locale name in the
+       user-supplied buffer BUF, which must be BUFSIZE bytes long.
+   The recommended minimum buffer size is
+     - SETLOCALE_NULL_MAX for CATEGORY != LC_ALL, and
+     - SETLOCALE_NULL_ALL_MAX for CATEGORY == LC_ALL.
+   The return value is an error code: 0 if the call is successful, EINVAL if
+   CATEGORY is invalid, or ERANGE if BUFSIZE is smaller than the length needed
+   size (including the trailing NUL byte).  In the latter case, a truncated
+   result is returned in BUF, but still NUL-terminated if BUFSIZE > 0.
+   For this call to be multithread-safe, *all* calls to
+   setlocale (CATEGORY, NULL) in all other threads must have been converted
+   to use setlocale_null_r or setlocale_null as well, and the other threads
+   must not make other setlocale invocations (since changing the global locale
+   has side effects on all threads).  */
+extern int setlocale_null_r (int category, char *buf, size_t bufsize)
+  _GL_ARG_NONNULL ((2));
+
+/* setlocale_null (CATEGORY) is like setlocale (CATEGORY, NULL), except that
+   it is guaranteed to be multithread-safe.
+   The return value is NULL if CATEGORY is invalid.
+   For this call to be multithread-safe, *all* calls to
+   setlocale (CATEGORY, NULL) in all other threads must have been converted
+   to use setlocale_null_r or setlocale_null as well, and the other threads
+   must not make other setlocale invocations (since changing the global locale
+   has side effects on all threads).  */
+extern const char *setlocale_null (int category);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* _SETLOCALE_NULL_H */