1/* wchar_t type related definitions.
2 Copyright (C) 2000-2020 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _BITS_WCHAR_H
20#define _BITS_WCHAR_H 1
21
22/* The fallback definitions, for when __WCHAR_MAX__ or __WCHAR_MIN__
23 are not defined, give the right value and type as long as both int
24 and wchar_t are 32-bit types. Adding L'\0' to a constant value
25 ensures that the type is correct; it is necessary to use (L'\0' +
26 0) rather than just L'\0' so that the type in C++ is the promoted
27 version of wchar_t rather than the distinct wchar_t type itself.
28 Because wchar_t in preprocessor #if expressions is treated as
29 intmax_t or uintmax_t, the expression (L'\0' - 1) would have the
30 wrong value for WCHAR_MAX in such expressions and so cannot be used
31 to define __WCHAR_MAX in the unsigned case. */
32
33#ifdef __WCHAR_MAX__
34# define __WCHAR_MAX __WCHAR_MAX__
35#elif L'\0' - 1 > 0
36# define __WCHAR_MAX (0xffffffffu + L'\0')
37#else
38# define __WCHAR_MAX (0x7fffffff + L'\0')
39#endif
40
41#ifdef __WCHAR_MIN__
42# define __WCHAR_MIN __WCHAR_MIN__
43#elif L'\0' - 1 > 0
44# define __WCHAR_MIN (L'\0' + 0)
45#else
46# define __WCHAR_MIN (-__WCHAR_MAX - 1)
47#endif
48
49#endif /* bits/wchar.h */
50

source code of include/x86_64-linux-gnu/bits/wchar.h