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authorAndreas Rottmann <a.rottmann@gmx.at>2009-09-14 12:34:39 +0200
committerAndreas Rottmann <a.rottmann@gmx.at>2009-09-14 12:34:39 +0200
commit79ca645d222db2e158784642c3b464a47bea26f3 (patch)
tree73fa0e7f2f509013ca7ea3395b268c8471b2355b /lib/stdbool.mini.h
parent8a927bfd7da41dbe61f3cfeaccbd37c761c0bc36 (diff)
parent3bebb94360f1c2333feb8d504a9fa4f96984d8b7 (diff)
Merge commit 'upstream/0.9.1.1'
Diffstat (limited to 'lib/stdbool.mini.h')
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+/* Copyright (C) 2001-2003, 2006-2009 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 _UNISTRING_STDBOOL_H
+#define _UNISTRING_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'.
+
+ 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 */
+
+/* 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
+ /* Assume the compiler has 'bool' and '_Bool'. */
+#else
+ /* 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".
+ 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
+#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 /* _UNISTRING_STDBOOL_H */