|
434
|
1 /* Copyright (C) 2001-2003, 2006-2010 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 */
|
