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Annotation of embedaddon/libiconv/srclib/stdbool.in.h, revision 1.1

1.1     ! misho       1: /* Copyright (C) 2001-2003, 2006-2008 Free Software Foundation, Inc.
        !             2:    Written by Bruno Haible <haible@clisp.cons.org>, 2001.
        !             3: 
        !             4:    This program is free software; you can redistribute it and/or modify
        !             5:    it under the terms of the GNU General Public License as published by
        !             6:    the Free Software Foundation; either version 3, or (at your option)
        !             7:    any later version.
        !             8: 
        !             9:    This program is distributed in the hope that it will be useful,
        !            10:    but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            11:    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            12:    GNU General Public License for more details.
        !            13: 
        !            14:    You should have received a copy of the GNU General Public License
        !            15:    along with this program; if not, write to the Free Software Foundation,
        !            16:    Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.  */
        !            17: 
        !            18: #ifndef _GL_STDBOOL_H
        !            19: #define _GL_STDBOOL_H
        !            20: 
        !            21: /* ISO C 99 <stdbool.h> for platforms that lack it.  */
        !            22: 
        !            23: /* Usage suggestions:
        !            24: 
        !            25:    Programs that use <stdbool.h> should be aware of some limitations
        !            26:    and standards compliance issues.
        !            27: 
        !            28:    Standards compliance:
        !            29: 
        !            30:        - <stdbool.h> must be #included before 'bool', 'false', 'true'
        !            31:          can be used.
        !            32: 
        !            33:        - You cannot assume that sizeof (bool) == 1.
        !            34: 
        !            35:        - Programs should not undefine the macros bool, true, and false,
        !            36:          as C99 lists that as an "obsolescent feature".
        !            37: 
        !            38:    Limitations of this substitute, when used in a C89 environment:
        !            39: 
        !            40:        - <stdbool.h> must be #included before the '_Bool' type can be used.
        !            41: 
        !            42:        - You cannot assume that _Bool is a typedef; it might be a macro.
        !            43: 
        !            44:        - Bit-fields of type 'bool' are not supported.  Portable code
        !            45:          should use 'unsigned int foo : 1;' rather than 'bool foo : 1;'.
        !            46: 
        !            47:        - In C99, casts and automatic conversions to '_Bool' or 'bool' are
        !            48:          performed in such a way that every nonzero value gets converted
        !            49:          to 'true', and zero gets converted to 'false'.  This doesn't work
        !            50:          with this substitute.  With this substitute, only the values 0 and 1
        !            51:          give the expected result when converted to _Bool' or 'bool'.
        !            52: 
        !            53:    Also, it is suggested that programs use 'bool' rather than '_Bool';
        !            54:    this isn't required, but 'bool' is more common.  */
        !            55: 
        !            56: 
        !            57: /* 7.16. Boolean type and values */
        !            58: 
        !            59: /* BeOS <sys/socket.h> already #defines false 0, true 1.  We use the same
        !            60:    definitions below, but temporarily we have to #undef them.  */
        !            61: #if defined __BEOS__ && !defined __HAIKU__
        !            62: # include <OS.h> /* defines bool but not _Bool */
        !            63: # undef false
        !            64: # undef true
        !            65: #endif
        !            66: 
        !            67: /* For the sake of symbolic names in gdb, we define true and false as
        !            68:    enum constants, not only as macros.
        !            69:    It is tempting to write
        !            70:       typedef enum { false = 0, true = 1 } _Bool;
        !            71:    so that gdb prints values of type 'bool' symbolically. But if we do
        !            72:    this, values of type '_Bool' may promote to 'int' or 'unsigned int'
        !            73:    (see ISO C 99 6.7.2.2.(4)); however, '_Bool' must promote to 'int'
        !            74:    (see ISO C 99 6.3.1.1.(2)).  So we add a negative value to the
        !            75:    enum; this ensures that '_Bool' promotes to 'int'.  */
        !            76: #if defined __cplusplus || (defined __BEOS__ && !defined __HAIKU__)
        !            77:   /* A compiler known to have 'bool'.  */
        !            78:   /* If the compiler already has both 'bool' and '_Bool', we can assume they
        !            79:      are the same types.  */
        !            80: # if !@HAVE__BOOL@
        !            81: typedef bool _Bool;
        !            82: # endif
        !            83: #else
        !            84: # if !defined __GNUC__
        !            85:    /* If @HAVE__BOOL@:
        !            86:         Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when
        !            87:         the built-in _Bool type is used.  See
        !            88:           http://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
        !            89:           http://lists.gnu.org/archive/html/bug-coreutils/2005-11/msg00161.html
        !            90:           http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html
        !            91:         Similar bugs are likely with other compilers as well; this file
        !            92:         wouldn't be used if <stdbool.h> was working.
        !            93:         So we override the _Bool type.
        !            94:       If !@HAVE__BOOL@:
        !            95:         Need to define _Bool ourselves. As 'signed char' or as an enum type?
        !            96:         Use of a typedef, with SunPRO C, leads to a stupid
        !            97:           "warning: _Bool is a keyword in ISO C99".
        !            98:         Use of an enum type, with IRIX cc, leads to a stupid
        !            99:           "warning(1185): enumerated type mixed with another type".
        !           100:         Even the existence of an enum type, without a typedef,
        !           101:           "Invalid enumerator. (badenum)" with HP-UX cc on Tru64.
        !           102:         The only benefit of the enum, debuggability, is not important
        !           103:         with these compilers.  So use 'signed char' and no enum.  */
        !           104: #  define _Bool signed char
        !           105: # else
        !           106:    /* With this compiler, trust the _Bool type if the compiler has it.  */
        !           107: #  if !@HAVE__BOOL@
        !           108: typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
        !           109: #  endif
        !           110: # endif
        !           111: #endif
        !           112: #define bool _Bool
        !           113: 
        !           114: /* The other macros must be usable in preprocessor directives.  */
        !           115: #define false 0
        !           116: #define true 1
        !           117: #define __bool_true_false_are_defined 1
        !           118: 
        !           119: #endif /* _GL_STDBOOL_H */