-/* Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
+/* Copyright (C) 2001, 2002, 2003, 2006 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
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
+ 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
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)). */
-#ifndef __cplusplus
+ (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__
+ /* 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@
-enum { false = 0, true = 1 };
-typedef signed char _Bool;
+typedef bool _Bool;
# endif
#else
-typedef bool _Bool;
+# 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
+ http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
+ http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
+ http://lists.gnu.org/archive/html/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".
+ The only benefit of the enum type, debuggability, is not important
+ with these compilers. So use 'signed char' and no typedef. */
+# define _Bool signed char
+enum { false = 0, true = 1 };
+# else
+ /* With this compiler, trust the _Bool type if the compiler has it. */
+# if !@HAVE__BOOL@
+typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
+# endif
+# endif
#endif
#define bool _Bool