| /* Copyright (C) 2001-2003, 2006-2019 Free Software Foundation, Inc. |
| Written by Bruno Haible <haible@clisp.cons.org>, 2001. |
| |
| 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, 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/>. */ |
| |
| #ifndef _GL_STDBOOL_H |
| #define _GL_STDBOOL_H |
| |
| /* ISO C 99 <stdbool.h> for platforms that lack it. */ |
| |
| /* Usage suggestions: |
| |
| Programs that use <stdbool.h> should be aware of some limitations |
| and standards compliance issues. |
| |
| Standards compliance: |
| |
| - <stdbool.h> must be #included before 'bool', 'false', 'true' |
| can be used. |
| |
| - You cannot assume that sizeof (bool) == 1. |
| |
| - Programs should not undefine the macros bool, true, and false, |
| as C99 lists that as an "obsolescent feature". |
| |
| Limitations of this substitute, when used in a C89 environment: |
| |
| - <stdbool.h> must be #included before the '_Bool' type can be used. |
| |
| - You cannot assume that _Bool is a typedef; it might be a macro. |
| |
| - Bit-fields of type 'bool' are not supported. Portable code |
| should use 'unsigned int foo : 1;' rather than 'bool foo : 1;'. |
| |
| - In C99, casts and automatic conversions to '_Bool' or 'bool' are |
| performed in such a way that every nonzero value gets converted |
| to 'true', and zero gets converted to 'false'. This doesn't work |
| with this substitute. With this substitute, only the values 0 and 1 |
| give the expected result when converted to _Bool' or 'bool'. |
| |
| - C99 allows the use of (_Bool)0.0 in constant expressions, but |
| this substitute cannot always provide this property. |
| |
| Also, it is suggested that programs use 'bool' rather than '_Bool'; |
| this isn't required, but 'bool' is more common. */ |
| |
| |
| /* 7.16. Boolean type and values */ |
| |
| /* BeOS <sys/socket.h> already #defines false 0, true 1. We use the same |
| definitions below, but temporarily we have to #undef them. */ |
| #if defined __BEOS__ && !defined __HAIKU__ |
| # include <OS.h> /* defines bool but not _Bool */ |
| # undef false |
| # undef true |
| #endif |
| |
| #ifdef __cplusplus |
| # define _Bool bool |
| # define bool bool |
| #else |
| # if defined __BEOS__ && !defined __HAIKU__ |
| /* A compiler known to have 'bool'. */ |
| /* If the compiler already has both 'bool' and '_Bool', we can assume they |
| are the same types. */ |
| # if !@HAVE__BOOL@ |
| typedef bool _Bool; |
| # endif |
| # else |
| # if !defined __GNUC__ |
| /* If @HAVE__BOOL@: |
| Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when |
| the built-in _Bool type is used. See |
| https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html |
| https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html |
| https://lists.gnu.org/r/bug-coreutils/2005-10/msg00086.html |
| Similar bugs are likely with other compilers as well; this file |
| wouldn't be used if <stdbool.h> was working. |
| So we override the _Bool type. |
| If !@HAVE__BOOL@: |
| Need to define _Bool ourselves. As 'signed char' or as an enum type? |
| Use of a typedef, with SunPRO C, leads to a stupid |
| "warning: _Bool is a keyword in ISO C99". |
| Use of an enum type, with IRIX cc, leads to a stupid |
| "warning(1185): enumerated type mixed with another type". |
| Even the existence of an enum type, without a typedef, |
| "Invalid enumerator. (badenum)" with HP-UX cc on Tru64. |
| The only benefit of the enum, debuggability, is not important |
| with these compilers. So use 'signed char' and no enum. */ |
| # define _Bool signed char |
| # else |
| /* With this compiler, trust the _Bool type if the compiler has it. */ |
| # if !@HAVE__BOOL@ |
| /* For the sake of symbolic names in gdb, define true and false as |
| enum constants, not only as macros. |
| It is tempting to write |
| typedef enum { false = 0, true = 1 } _Bool; |
| so that gdb prints values of type 'bool' symbolically. But then |
| values of type '_Bool' might promote to 'int' or 'unsigned int' |
| (see ISO C 99 6.7.2.2.(4)); however, '_Bool' must promote to 'int' |
| (see ISO C 99 6.3.1.1.(2)). So add a negative value to the |
| enum; this ensures that '_Bool' promotes to 'int'. */ |
| typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool; |
| # endif |
| # endif |
| # endif |
| # define bool _Bool |
| #endif |
| |
| /* The other macros must be usable in preprocessor directives. */ |
| #ifdef __cplusplus |
| # define false false |
| # define true true |
| #else |
| # define false 0 |
| # define true 1 |
| #endif |
| |
| #define __bool_true_false_are_defined 1 |
| |
| #endif /* _GL_STDBOOL_H */ |