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thodg/libiconv/srclib/stdbool_.h

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  • Author : Bruno Haible
    Date : 2005-12-29 13:06:22
    Hash : 1f290a21
    Message : Update from GNU gettext.

  • srclib/stdbool_.h
  • /* 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 */