1// (C) Copyright John Maddock 2000.
2// Use, modification and distribution are subject to the
3// Boost Software License, Version 1.0. (See accompanying file
4// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6// See http://www.boost.org/libs/static_assert for documentation.
7
8/*
9 Revision history:
10 02 August 2000
11 Initial version.
12*/
13
14#ifndef BOOST_STATIC_ASSERT_HPP
15#define BOOST_STATIC_ASSERT_HPP
16
17#include <boost/config.hpp>
18#include <boost/detail/workaround.hpp>
19#include <cstddef> //for std::size_t
20
21#if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
22//
23// This is horrible, but it seems to be the only we can shut up the
24// "anonymous variadic macros were introduced in C99 [-Wvariadic-macros]"
25// warning that get spewed out otherwise in non-C++11 mode.
26//
27#pragma GCC system_header
28#endif
29
30#ifndef BOOST_NO_CXX11_STATIC_ASSERT
31# ifndef BOOST_NO_CXX11_VARIADIC_MACROS
32# define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__)
33# else
34# define BOOST_STATIC_ASSERT_MSG( B, Msg ) static_assert( B, Msg )
35# endif
36#else
37# define BOOST_STATIC_ASSERT_MSG( B, Msg ) BOOST_STATIC_ASSERT( B )
38#endif
39
40#ifdef BOOST_BORLANDC
41//
42// workaround for buggy integral-constant expression support:
43#define BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS
44#endif
45
46#if defined(__GNUC__) && (__GNUC__ == 3) && ((__GNUC_MINOR__ == 3) || (__GNUC_MINOR__ == 4))
47// gcc 3.3 and 3.4 don't produce good error messages with the default version:
48# define BOOST_SA_GCC_WORKAROUND
49#endif
50
51//
52// If the compiler issues warnings about old C style casts,
53// then enable this:
54//
55#if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4)))
56# ifndef BOOST_NO_CXX11_VARIADIC_MACROS
57# define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) ((__VA_ARGS__) != 0)
58# else
59# define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) != 0)
60# endif
61#else
62# ifndef BOOST_NO_CXX11_VARIADIC_MACROS
63# define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) (bool)(__VA_ARGS__)
64# else
65# define BOOST_STATIC_ASSERT_BOOL_CAST(x) (bool)(x)
66# endif
67#endif
68
69#ifndef BOOST_NO_CXX11_STATIC_ASSERT
70# ifndef BOOST_NO_CXX11_VARIADIC_MACROS
71# define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__)
72# else
73# define BOOST_STATIC_ASSERT( B ) static_assert(B, #B)
74# endif
75#else
76
77namespace boost{
78
79// HP aCC cannot deal with missing names for template value parameters
80template <bool x> struct STATIC_ASSERTION_FAILURE;
81
82template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; };
83
84// HP aCC cannot deal with missing names for template value parameters
85template<std::size_t x> struct static_assert_test{};
86
87}
88
89//
90// Implicit instantiation requires that all member declarations be
91// instantiated, but that the definitions are *not* instantiated.
92//
93// It's not particularly clear how this applies to enum's or typedefs;
94// both are described as declarations [7.1.3] and [7.2] in the standard,
95// however some compilers use "delayed evaluation" of one or more of
96// these when implicitly instantiating templates. We use typedef declarations
97// by default, but try defining BOOST_USE_ENUM_STATIC_ASSERT if the enum
98// version gets better results from your compiler...
99//
100// Implementation:
101// Both of these versions rely on sizeof(incomplete_type) generating an error
102// message containing the name of the incomplete type. We use
103// "STATIC_ASSERTION_FAILURE" as the type name here to generate
104// an eye catching error message. The result of the sizeof expression is either
105// used as an enum initialiser, or as a template argument depending which version
106// is in use...
107// Note that the argument to the assert is explicitly cast to bool using old-
108// style casts: too many compilers currently have problems with static_cast
109// when used inside integral constant expressions.
110//
111#if !defined(BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS)
112
113#if defined(BOOST_MSVC) && defined(BOOST_NO_CXX11_VARIADIC_MACROS)
114#define BOOST_STATIC_ASSERT( B ) \
115 typedef ::boost::static_assert_test<\
116 sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST ( B ) >)>\
117 BOOST_JOIN(boost_static_assert_typedef_, __COUNTER__)
118#elif defined(BOOST_MSVC)
119#define BOOST_STATIC_ASSERT(...) \
120 typedef ::boost::static_assert_test<\
121 sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST (__VA_ARGS__) >)>\
122 BOOST_JOIN(boost_static_assert_typedef_, __COUNTER__)
123#elif (defined(BOOST_INTEL_CXX_VERSION) || defined(BOOST_SA_GCC_WORKAROUND)) && defined(BOOST_NO_CXX11_VARIADIC_MACROS)
124// agurt 15/sep/02: a special care is needed to force Intel C++ issue an error
125// instead of warning in case of failure
126# define BOOST_STATIC_ASSERT( B ) \
127 typedef char BOOST_JOIN(boost_static_assert_typedef_, __LINE__) \
128 [ ::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >::value ]
129#elif (defined(BOOST_INTEL_CXX_VERSION) || defined(BOOST_SA_GCC_WORKAROUND)) && !defined(BOOST_NO_CXX11_VARIADIC_MACROS)
130// agurt 15/sep/02: a special care is needed to force Intel C++ issue an error
131// instead of warning in case of failure
132# define BOOST_STATIC_ASSERT(...) \
133 typedef char BOOST_JOIN(boost_static_assert_typedef_, __LINE__) \
134 [ ::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( __VA_ARGS__ ) >::value ]
135#elif defined(__sgi)
136// special version for SGI MIPSpro compiler
137#define BOOST_STATIC_ASSERT( B ) \
138 BOOST_STATIC_CONSTANT(bool, \
139 BOOST_JOIN(boost_static_assert_test_, __LINE__) = ( B )); \
140 typedef ::boost::static_assert_test<\
141 sizeof(::boost::STATIC_ASSERTION_FAILURE< \
142 BOOST_JOIN(boost_static_assert_test_, __LINE__) >)>\
143 BOOST_JOIN(boost_static_assert_typedef_, __LINE__)
144#elif BOOST_WORKAROUND(__MWERKS__, <= 0x3003)
145// special version for CodeWarrior <= 8.x
146#define BOOST_STATIC_ASSERT( B ) \
147 BOOST_STATIC_CONSTANT(int, \
148 BOOST_JOIN(boost_static_assert_test_, __LINE__) = \
149 sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >) )
150#else
151// generic version
152# ifndef BOOST_NO_CXX11_VARIADIC_MACROS
153# define BOOST_STATIC_ASSERT( ... ) \
154 typedef ::boost::static_assert_test<\
155 sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( __VA_ARGS__ ) >)>\
156 BOOST_JOIN(boost_static_assert_typedef_, __LINE__) BOOST_ATTRIBUTE_UNUSED
157# else
158# define BOOST_STATIC_ASSERT( B ) \
159 typedef ::boost::static_assert_test<\
160 sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\
161 BOOST_JOIN(boost_static_assert_typedef_, __LINE__) BOOST_ATTRIBUTE_UNUSED
162# endif
163#endif
164
165#else
166// alternative enum based implementation:
167# ifndef BOOST_NO_CXX11_VARIADIC_MACROS
168# define BOOST_STATIC_ASSERT( ... ) \
169 enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
170 = sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( __VA_ARGS__ ) >) }
171# else
172# define BOOST_STATIC_ASSERT(B) \
173 enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
174 = sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >) }
175# endif
176#endif
177#endif // defined(BOOST_NO_CXX11_STATIC_ASSERT)
178
179#endif // BOOST_STATIC_ASSERT_HPP
180
181
182

source code of boost/libs/static_assert/include/boost/static_assert.hpp