| /* Copyright (C) 2001, 2002, 2003 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 2, 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, write to the Free Software Foundation, |
| Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ |
| |
| #ifndef _STDBOOL_H |
| #define _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. |
| |
| - 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'. |
| |
| 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. */ |
| #ifdef __BEOS__ |
| # include <OS.h> /* defines bool but not _Bool */ |
| # undef false |
| # undef true |
| #endif |
| |
| /* For the sake of symbolic names in gdb, we 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 if we do |
| this, values of type '_Bool' may 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 we add a negative value to the |
| enum; this ensures that '_Bool' promotes to 'int'. */ |
| #if !(defined __cplusplus || defined __BEOS__) |
| # if !@HAVE__BOOL@ |
| # if defined __SUNPRO_C && (__SUNPRO_C < 0x550 || __STDC__ == 1) |
| /* Avoid stupid "warning: _Bool is a keyword in ISO C99". */ |
| # define _Bool signed char |
| enum { false = 0, true = 1 }; |
| # else |
| typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool; |
| # endif |
| # endif |
| #else |
| typedef bool _Bool; |
| #endif |
| #define bool _Bool |
| |
| /* The other macros must be usable in preprocessor directives. */ |
| #define false 0 |
| #define true 1 |
| #define __bool_true_false_are_defined 1 |
| |
| #endif /* _STDBOOL_H */ |