+2012-08-29 Paul Eggert <eggert@cs.ucla.edu>
+
+ stdbool: be more compatible with mixed C/C++ compiles
+ * lib/stdbool.in.h (_Bool, true, false) [__cplusplus]:
+ Define to bool, true, false, respectively, as GCC's builtin
+ stdbool.h does. Problem reported by Michael Goffioul in
+ <http://lists.gnu.org/archive/html/bug-gnulib/2012-08/msg00143.html>.
+
2012-08-28 Jim Meyering <meyering@redhat.com>
revert last change: it was not needed
# 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__ && !defined __HAIKU__)
+#ifdef __cplusplus
+# 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@
+# if !@HAVE__BOOL@
typedef bool _Bool;
-# endif
-#else
-# if !defined __GNUC__
+# 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
"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
+# define _Bool signed char
+# else
/* With this compiler, trust the _Bool type if the compiler has it. */
-# if !@HAVE__BOOL@
+# 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
#endif
#define bool _Bool
/* The other macros must be usable in preprocessor directives. */
-#define false 0
-#define true 1
+#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 */