Annotation of embedaddon/libiconv/srclib/stdbool.in.h, revision 1.1.1.3
1.1.1.3 ! misho 1: /* Copyright (C) 2001-2003, 2006-2019 Free Software Foundation, Inc.
1.1 misho 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
1.1.1.3 ! misho 15: along with this program; if not, see <https://www.gnu.org/licenses/>. */
1.1 misho 16:
17: #ifndef _GL_STDBOOL_H
18: #define _GL_STDBOOL_H
19:
20: /* ISO C 99 <stdbool.h> for platforms that lack it. */
21:
22: /* Usage suggestions:
23:
24: Programs that use <stdbool.h> should be aware of some limitations
25: and standards compliance issues.
26:
27: Standards compliance:
28:
29: - <stdbool.h> must be #included before 'bool', 'false', 'true'
30: can be used.
31:
32: - You cannot assume that sizeof (bool) == 1.
33:
34: - Programs should not undefine the macros bool, true, and false,
35: as C99 lists that as an "obsolescent feature".
36:
37: Limitations of this substitute, when used in a C89 environment:
38:
39: - <stdbool.h> must be #included before the '_Bool' type can be used.
40:
41: - You cannot assume that _Bool is a typedef; it might be a macro.
42:
43: - Bit-fields of type 'bool' are not supported. Portable code
44: should use 'unsigned int foo : 1;' rather than 'bool foo : 1;'.
45:
46: - In C99, casts and automatic conversions to '_Bool' or 'bool' are
47: performed in such a way that every nonzero value gets converted
48: to 'true', and zero gets converted to 'false'. This doesn't work
49: with this substitute. With this substitute, only the values 0 and 1
50: give the expected result when converted to _Bool' or 'bool'.
51:
1.1.1.2 misho 52: - C99 allows the use of (_Bool)0.0 in constant expressions, but
53: this substitute cannot always provide this property.
54:
1.1 misho 55: Also, it is suggested that programs use 'bool' rather than '_Bool';
56: this isn't required, but 'bool' is more common. */
57:
58:
59: /* 7.16. Boolean type and values */
60:
61: /* BeOS <sys/socket.h> already #defines false 0, true 1. We use the same
62: definitions below, but temporarily we have to #undef them. */
63: #if defined __BEOS__ && !defined __HAIKU__
64: # include <OS.h> /* defines bool but not _Bool */
65: # undef false
66: # undef true
67: #endif
68:
1.1.1.3 ! misho 69: #ifdef __cplusplus
! 70: # define _Bool bool
! 71: # define bool bool
! 72: #else
! 73: # if defined __BEOS__ && !defined __HAIKU__
1.1 misho 74: /* A compiler known to have 'bool'. */
75: /* If the compiler already has both 'bool' and '_Bool', we can assume they
76: are the same types. */
1.1.1.3 ! misho 77: # if !@HAVE__BOOL@
1.1 misho 78: typedef bool _Bool;
1.1.1.3 ! misho 79: # endif
! 80: # else
! 81: # if !defined __GNUC__
1.1 misho 82: /* If @HAVE__BOOL@:
83: Some HP-UX cc and AIX IBM C compiler versions have compiler bugs when
84: the built-in _Bool type is used. See
1.1.1.3 ! misho 85: https://gcc.gnu.org/ml/gcc-patches/2003-12/msg02303.html
! 86: https://lists.gnu.org/r/bug-coreutils/2005-11/msg00161.html
! 87: https://lists.gnu.org/r/bug-coreutils/2005-10/msg00086.html
1.1 misho 88: Similar bugs are likely with other compilers as well; this file
89: wouldn't be used if <stdbool.h> was working.
90: So we override the _Bool type.
91: If !@HAVE__BOOL@:
92: Need to define _Bool ourselves. As 'signed char' or as an enum type?
93: Use of a typedef, with SunPRO C, leads to a stupid
94: "warning: _Bool is a keyword in ISO C99".
95: Use of an enum type, with IRIX cc, leads to a stupid
96: "warning(1185): enumerated type mixed with another type".
97: Even the existence of an enum type, without a typedef,
98: "Invalid enumerator. (badenum)" with HP-UX cc on Tru64.
99: The only benefit of the enum, debuggability, is not important
100: with these compilers. So use 'signed char' and no enum. */
1.1.1.3 ! misho 101: # define _Bool signed char
! 102: # else
1.1 misho 103: /* With this compiler, trust the _Bool type if the compiler has it. */
1.1.1.3 ! misho 104: # if !@HAVE__BOOL@
! 105: /* For the sake of symbolic names in gdb, define true and false as
! 106: enum constants, not only as macros.
! 107: It is tempting to write
! 108: typedef enum { false = 0, true = 1 } _Bool;
! 109: so that gdb prints values of type 'bool' symbolically. But then
! 110: values of type '_Bool' might promote to 'int' or 'unsigned int'
! 111: (see ISO C 99 6.7.2.2.(4)); however, '_Bool' must promote to 'int'
! 112: (see ISO C 99 6.3.1.1.(2)). So add a negative value to the
! 113: enum; this ensures that '_Bool' promotes to 'int'. */
1.1 misho 114: typedef enum { _Bool_must_promote_to_int = -1, false = 0, true = 1 } _Bool;
1.1.1.3 ! misho 115: # endif
1.1 misho 116: # endif
117: # endif
1.1.1.3 ! misho 118: # define bool _Bool
1.1 misho 119: #endif
120:
121: /* The other macros must be usable in preprocessor directives. */
1.1.1.3 ! misho 122: #ifdef __cplusplus
! 123: # define false false
! 124: # define true true
! 125: #else
! 126: # define false 0
! 127: # define true 1
! 128: #endif
! 129:
1.1 misho 130: #define __bool_true_false_are_defined 1
131:
132: #endif /* _GL_STDBOOL_H */
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