boost/static_assert.hpp

   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
  20 #if defined(__GNUC__) && !defined(__GXX_EXPERIMENTAL_CXX0X__)
  21 //
  22 // This is horrible, but it seems to be the only we can shut up the
  23 // "anonymous variadic macros were introduced in C99 [-Wvariadic-macros]"
  24 // warning that get spewed out otherwise in non-C++11 mode.
  25 //
  26 #pragma GCC system_header
  27 #endif
  28
  29 #ifndef BOOST_NO_CXX11_STATIC_ASSERT
  30 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
  31 #     define BOOST_STATIC_ASSERT_MSG( ... ) static_assert(__VA_ARGS__)
  32 #  else
  33 #     define BOOST_STATIC_ASSERT_MSG( B, Msg ) BOOST_STATIC_ASSERT( B )
  34 #  endif
  35 #else
  36 #     define BOOST_STATIC_ASSERT_MSG( B, Msg ) BOOST_STATIC_ASSERT( B )
  37 #endif
  38
  39 #ifdef __BORLANDC__
  40 //
  41 // workaround for buggy integral-constant expression support:
  42 #define BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS
  43 #endif
  44
  45 #if defined(__GNUC__) && (__GNUC__ == 3) && ((__GNUC_MINOR__ == 3) || (__GNUC_MINOR__ == 4))
  46 // gcc 3.3 and 3.4 don't produce good error messages with the default version:
  47 #  define BOOST_SA_GCC_WORKAROUND
  48 #endif
  49
  50 //
  51 // If the compiler issues warnings about old C style casts,
  52 // then enable this:
  53 //
  54 #if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4)))
  55 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
  56 #     define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) ((__VA_ARGS__) == 0 ? false : true)
  57 #  else
  58 #     define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) == 0 ? false : true)
  59 #  endif
  60 #else
  61 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
  62 #     define BOOST_STATIC_ASSERT_BOOL_CAST( ... ) (bool)(__VA_ARGS__)
  63 #  else
  64 #     define BOOST_STATIC_ASSERT_BOOL_CAST(x) (bool)(x)
  65 #  endif
  66 #endif
  67 //
  68 // If the compiler warns about unused typedefs then enable this:
  69 //
  70 #if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 7)))
  71 #  define BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE __attribute__((unused))
  72 #else
  73 #  define BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE
  74 #endif
  75
  76 #ifndef BOOST_NO_CXX11_STATIC_ASSERT
  77 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
  78 #     define BOOST_STATIC_ASSERT( ... ) static_assert(__VA_ARGS__, #__VA_ARGS__)
  79 #  else
  80 #     define BOOST_STATIC_ASSERT( B ) static_assert(B, #B)
  81 #  endif
  82 #else
  83
  84 namespace boost{
  85
  86 // HP aCC cannot deal with missing names for template value parameters
  87 template <bool x> struct STATIC_ASSERTION_FAILURE;
  88
  89 template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; };
  90
  91 // HP aCC cannot deal with missing names for template value parameters
  92 template<int x> struct static_assert_test{};
  93
  94 }
  95
  96 //
  97 // Implicit instantiation requires that all member declarations be
  98 // instantiated, but that the definitions are *not* instantiated.
  99 //
 100 // It's not particularly clear how this applies to enum's or typedefs;
 101 // both are described as declarations [7.1.3] and [7.2] in the standard,
 102 // however some compilers use "delayed evaluation" of one or more of
 103 // these when implicitly instantiating templates.  We use typedef declarations
 104 // by default, but try defining BOOST_USE_ENUM_STATIC_ASSERT if the enum
 105 // version gets better results from your compiler...
 106 //
 107 // Implementation:
 108 // Both of these versions rely on sizeof(incomplete_type) generating an error
 109 // message containing the name of the incomplete type.  We use
 110 // "STATIC_ASSERTION_FAILURE" as the type name here to generate
 111 // an eye catching error message.  The result of the sizeof expression is either
 112 // used as an enum initialiser, or as a template argument depending which version
 113 // is in use...
 114 // Note that the argument to the assert is explicitly cast to bool using old-
 115 // style casts: too many compilers currently have problems with static_cast
 116 // when used inside integral constant expressions.
 117 //
 118 #if !defined(BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS)
 119
 120 #if defined(BOOST_MSVC) && (BOOST_MSVC < 1300)
 121 // __LINE__ macro broken when -ZI is used see Q199057
 122 // fortunately MSVC ignores duplicate typedef's.
 123 #define BOOST_STATIC_ASSERT( B ) \
 124    typedef ::boost::static_assert_test<\
 125       sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >)\
 126       > boost_static_assert_typedef_
 127 #elif defined(BOOST_MSVC) && defined(BOOST_NO_CXX11_VARIADIC_MACROS)
 128 #define BOOST_STATIC_ASSERT( B ) \
 129    typedef ::boost::static_assert_test<\
 130       sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST ( B ) >)>\
 131          BOOST_JOIN(boost_static_assert_typedef_, __COUNTER__)
 132 #elif defined(BOOST_MSVC)
 133 #define BOOST_STATIC_ASSERT(...) \
 134    typedef ::boost::static_assert_test<\
 135       sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST (__VA_ARGS__) >)>\
 136          BOOST_JOIN(boost_static_assert_typedef_, __COUNTER__)
 137 #elif (defined(BOOST_INTEL_CXX_VERSION) || defined(BOOST_SA_GCC_WORKAROUND))  && defined(BOOST_NO_CXX11_VARIADIC_MACROS)
 138 // agurt 15/sep/02: a special care is needed to force Intel C++ issue an error
 139 // instead of warning in case of failure
 140 # define BOOST_STATIC_ASSERT( B ) \
 141     typedef char BOOST_JOIN(boost_static_assert_typedef_, __LINE__) \
 142         [ ::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >::value ]
 143 #elif (defined(BOOST_INTEL_CXX_VERSION) || defined(BOOST_SA_GCC_WORKAROUND))  && !defined(BOOST_NO_CXX11_VARIADIC_MACROS)
 144 // agurt 15/sep/02: a special care is needed to force Intel C++ issue an error
 145 // instead of warning in case of failure
 146 # define BOOST_STATIC_ASSERT(...) \
 147     typedef char BOOST_JOIN(boost_static_assert_typedef_, __LINE__) \
 148         [ ::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( __VA_ARGS__ ) >::value ]
 149 #elif defined(__sgi)
 150 // special version for SGI MIPSpro compiler
 151 #define BOOST_STATIC_ASSERT( B ) \
 152    BOOST_STATIC_CONSTANT(bool, \
 153      BOOST_JOIN(boost_static_assert_test_, __LINE__) = ( B )); \
 154    typedef ::boost::static_assert_test<\
 155      sizeof(::boost::STATIC_ASSERTION_FAILURE< \
 156        BOOST_JOIN(boost_static_assert_test_, __LINE__) >)>\
 157          BOOST_JOIN(boost_static_assert_typedef_, __LINE__)
 158 #elif BOOST_WORKAROUND(__MWERKS__, <= 0x3003)
 159 // special version for CodeWarrior <= 8.x
 160 #define BOOST_STATIC_ASSERT( B ) \
 161    BOOST_STATIC_CONSTANT(int, \
 162      BOOST_JOIN(boost_static_assert_test_, __LINE__) = \
 163        sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >) )
 164 #else
 165 // generic version
 166 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
 167 #     define BOOST_STATIC_ASSERT( ... ) \
 168          typedef ::boost::static_assert_test<\
 169             sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( __VA_ARGS__ ) >)>\
 170                BOOST_JOIN(boost_static_assert_typedef_, __LINE__) BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE
 171 #  else
 172 #     define BOOST_STATIC_ASSERT( B ) \
 173          typedef ::boost::static_assert_test<\
 174             sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\
 175                BOOST_JOIN(boost_static_assert_typedef_, __LINE__) BOOST_STATIC_ASSERT_UNUSED_ATTRIBUTE
 176 #  endif
 177 #endif
 178
 179 #else
 180 // alternative enum based implementation:
 181 #  ifndef BOOST_NO_CXX11_VARIADIC_MACROS
 182 #    define BOOST_STATIC_ASSERT( ... ) \
 183          enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
 184             = sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( __VA_ARGS__ ) >) }
 185 #  else
 186 #    define BOOST_STATIC_ASSERT(B) \
 187          enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
 188             = sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >) }
 189 #  endif
 190 #endif
 191 #endif // defined(BOOST_NO_CXX11_STATIC_ASSERT)
 192
 193 #endif // BOOST_STATIC_ASSERT_HPP
 194
 195