1/*
2 * Copyright Andrey Semashev 2007 - 2013.
3 * Distributed under the Boost Software License, Version 1.0.
4 * (See accompanying file LICENSE_1_0.txt or copy at
5 * http://www.boost.org/LICENSE_1_0.txt)
6 */
7
8/*!
9 * \file explicit_operator_bool.hpp
10 * \author Andrey Semashev
11 * \date 08.03.2009
12 *
13 * This header defines a compatibility macro that implements an unspecified
14 * \c bool operator idiom, which is superseded with explicit conversion operators in
15 * C++11.
16 */
17
18#ifndef BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP
19#define BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP
20
21#include <boost/config.hpp>
22
23#ifdef BOOST_HAS_PRAGMA_ONCE
24#pragma once
25#endif
26
27#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
28
29/*!
30 * \brief The macro defines an explicit operator of conversion to \c bool
31 *
32 * The macro should be used inside the definition of a class that has to
33 * support the conversion. The class should also implement <tt>operator!</tt>,
34 * in terms of which the conversion operator will be implemented.
35 */
36#define BOOST_EXPLICIT_OPERATOR_BOOL()\
37 BOOST_FORCEINLINE explicit operator bool () const\
38 {\
39 return !this->operator! ();\
40 }
41
42/*!
43 * \brief The macro defines a noexcept explicit operator of conversion to \c bool
44 *
45 * The macro should be used inside the definition of a class that has to
46 * support the conversion. The class should also implement <tt>operator!</tt>,
47 * in terms of which the conversion operator will be implemented.
48 */
49#define BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()\
50 BOOST_FORCEINLINE explicit operator bool () const BOOST_NOEXCEPT\
51 {\
52 return !this->operator! ();\
53 }
54
55/*!
56 * \brief The macro defines a constexpr explicit operator of conversion to \c bool
57 *
58 * The macro should be used inside the definition of a class that has to
59 * support the conversion. The class should also implement <tt>operator!</tt>,
60 * in terms of which the conversion operator will be implemented.
61 */
62#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL()\
63 BOOST_FORCEINLINE BOOST_CONSTEXPR explicit operator bool () const BOOST_NOEXCEPT\
64 {\
65 return !this->operator! ();\
66 }
67
68#else // !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
69
70#if (defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530)) && !defined(BOOST_NO_COMPILER_CONFIG)
71// Sun C++ 5.3 can't handle the safe_bool idiom, so don't use it
72#define BOOST_NO_UNSPECIFIED_BOOL
73#endif // (defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530)) && !defined(BOOST_NO_COMPILER_CONFIG)
74
75#if !defined(BOOST_NO_UNSPECIFIED_BOOL)
76
77namespace boost {
78
79namespace detail {
80
81#if !defined(_MSC_VER) && !defined(__IBMCPP__)
82
83 struct unspecified_bool
84 {
85 // NOTE TO THE USER: If you see this in error messages then you tried
86 // to apply an unsupported operator on the object that supports
87 // explicit conversion to bool.
88 struct OPERATORS_NOT_ALLOWED;
89 static void true_value(OPERATORS_NOT_ALLOWED*) {}
90 };
91 typedef void (*unspecified_bool_type)(unspecified_bool::OPERATORS_NOT_ALLOWED*);
92
93#else
94
95 // MSVC and VACPP are too eager to convert pointer to function to void* even though they shouldn't
96 struct unspecified_bool
97 {
98 // NOTE TO THE USER: If you see this in error messages then you tried
99 // to apply an unsupported operator on the object that supports
100 // explicit conversion to bool.
101 struct OPERATORS_NOT_ALLOWED;
102 void true_value(OPERATORS_NOT_ALLOWED*) {}
103 };
104 typedef void (unspecified_bool::*unspecified_bool_type)(unspecified_bool::OPERATORS_NOT_ALLOWED*);
105
106#endif
107
108} // namespace detail
109
110} // namespace boost
111
112#define BOOST_EXPLICIT_OPERATOR_BOOL()\
113 BOOST_FORCEINLINE operator boost::detail::unspecified_bool_type () const\
114 {\
115 return (!this->operator! () ? &boost::detail::unspecified_bool::true_value : (boost::detail::unspecified_bool_type)0);\
116 }
117
118#define BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()\
119 BOOST_FORCEINLINE operator boost::detail::unspecified_bool_type () const BOOST_NOEXCEPT\
120 {\
121 return (!this->operator! () ? &boost::detail::unspecified_bool::true_value : (boost::detail::unspecified_bool_type)0);\
122 }
123
124#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL()\
125 BOOST_FORCEINLINE BOOST_CONSTEXPR operator boost::detail::unspecified_bool_type () const BOOST_NOEXCEPT\
126 {\
127 return (!this->operator! () ? &boost::detail::unspecified_bool::true_value : (boost::detail::unspecified_bool_type)0);\
128 }
129
130#else // !defined(BOOST_NO_UNSPECIFIED_BOOL)
131
132#define BOOST_EXPLICIT_OPERATOR_BOOL()\
133 BOOST_FORCEINLINE operator bool () const\
134 {\
135 return !this->operator! ();\
136 }
137
138#define BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()\
139 BOOST_FORCEINLINE operator bool () const BOOST_NOEXCEPT\
140 {\
141 return !this->operator! ();\
142 }
143
144#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL()\
145 BOOST_FORCEINLINE BOOST_CONSTEXPR operator bool () const BOOST_NOEXCEPT\
146 {\
147 return !this->operator! ();\
148 }
149
150#endif // !defined(BOOST_NO_UNSPECIFIED_BOOL)
151
152#endif // !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
153
154#endif // BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP
155