Edit: wchar.h
/* wchar_t type related definitions. Copyright (C) 2000-2018 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library 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. The GNU C Library 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 the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ #ifndef _BITS_WCHAR_H #define _BITS_WCHAR_H 1 /* The fallback definitions, for when __WCHAR_MAX__ or __WCHAR_MIN__ are not defined, give the right value and type as long as both int and wchar_t are 32-bit types. Adding L'\0' to a constant value ensures that the type is correct; it is necessary to use (L'\0' + 0) rather than just L'\0' so that the type in C++ is the promoted version of wchar_t rather than the distinct wchar_t type itself. Because wchar_t in preprocessor #if expressions is treated as intmax_t or uintmax_t, the expression (L'\0' - 1) would have the wrong value for WCHAR_MAX in such expressions and so cannot be used to define __WCHAR_MAX in the unsigned case. */ #ifdef __WCHAR_MAX__ # define __WCHAR_MAX __WCHAR_MAX__ #elif L'\0' - 1 > 0 # define __WCHAR_MAX (0xffffffffu + L'\0') #else # define __WCHAR_MAX (0x7fffffff + L'\0') #endif #ifdef __WCHAR_MIN__ # define __WCHAR_MIN __WCHAR_MIN__ #elif L'\0' - 1 > 0 # define __WCHAR_MIN (L'\0' + 0) #else # define __WCHAR_MIN (-__WCHAR_MAX - 1) #endif #endif /* bits/wchar.h */
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