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 #ifdef __BORLANDC__
  21 //
  22 // workaround for buggy integral-constant expression support:
  23 #define BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS
  24 #endif
  25
  26 #if defined(__GNUC__) && (__GNUC__ == 3) && ((__GNUC_MINOR__ == 3) || (__GNUC_MINOR__ == 4))
  27 // gcc 3.3 and 3.4 don't produce good error messages with the default version:
  28 #  define BOOST_SA_GCC_WORKAROUND
  29 #endif
  30
  31 //
  32 // If the compiler issues warnings about old C style casts,
  33 // then enable this:
  34 //
  35 #if defined(__GNUC__) && ((__GNUC__ > 3) || ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 4)))
  36 #  define BOOST_STATIC_ASSERT_BOOL_CAST( x ) ((x) == 0 ? false : true)
  37 #else
  38 #  define BOOST_STATIC_ASSERT_BOOL_CAST(x) (bool)(x)
  39 #endif
  40
  41 #ifdef BOOST_HAS_STATIC_ASSERT
  42 #  define BOOST_STATIC_ASSERT( B ) static_assert(B, #B)
  43 #else
  44
  45 namespace boost{
  46
  47 // HP aCC cannot deal with missing names for template value parameters
  48 template <bool x> struct STATIC_ASSERTION_FAILURE;
  49
  50 template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; };
  51
  52 // HP aCC cannot deal with missing names for template value parameters
  53 template<int x> struct static_assert_test{};
  54
  55 }
  56
  57 //
  58 // Implicit instantiation requires that all member declarations be
  59 // instantiated, but that the definitions are *not* instantiated.
  60 //
  61 // It's not particularly clear how this applies to enum's or typedefs;
  62 // both are described as declarations [7.1.3] and [7.2] in the standard,
  63 // however some compilers use "delayed evaluation" of one or more of
  64 // these when implicitly instantiating templates.  We use typedef declarations
  65 // by default, but try defining BOOST_USE_ENUM_STATIC_ASSERT if the enum
  66 // version gets better results from your compiler...
  67 //
  68 // Implementation:
  69 // Both of these versions rely on sizeof(incomplete_type) generating an error
  70 // message containing the name of the incomplete type.  We use
  71 // "STATIC_ASSERTION_FAILURE" as the type name here to generate
  72 // an eye catching error message.  The result of the sizeof expression is either
  73 // used as an enum initialiser, or as a template argument depending which version
  74 // is in use...
  75 // Note that the argument to the assert is explicitly cast to bool using old-
  76 // style casts: too many compilers currently have problems with static_cast
  77 // when used inside integral constant expressions.
  78 //
  79 #if !defined(BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS)
  80
  81 #if defined(BOOST_MSVC) && (BOOST_MSVC < 1300)
  82 // __LINE__ macro broken when -ZI is used see Q199057
  83 // fortunately MSVC ignores duplicate typedef's.
  84 #define BOOST_STATIC_ASSERT( B ) \
  85    typedef ::boost::static_assert_test<\
  86       sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >)\
  87       > boost_static_assert_typedef_
  88 #elif defined(BOOST_MSVC)
  89 #define BOOST_STATIC_ASSERT( B ) \
  90    typedef ::boost::static_assert_test<\
  91       sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST ( B ) >)>\
  92          BOOST_JOIN(boost_static_assert_typedef_, __COUNTER__)
  93 #elif defined(BOOST_INTEL_CXX_VERSION) || defined(BOOST_SA_GCC_WORKAROUND)
  94 // agurt 15/sep/02: a special care is needed to force Intel C++ issue an error
  95 // instead of warning in case of failure
  96 # define BOOST_STATIC_ASSERT( B ) \
  97     typedef char BOOST_JOIN(boost_static_assert_typedef_, __LINE__) \
  98         [ ::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >::value ]
  99 #elif defined(__sgi)
 100 // special version for SGI MIPSpro compiler
 101 #define BOOST_STATIC_ASSERT( B ) \
 102    BOOST_STATIC_CONSTANT(bool, \
 103      BOOST_JOIN(boost_static_assert_test_, __LINE__) = ( B )); \
 104    typedef ::boost::static_assert_test<\
 105      sizeof(::boost::STATIC_ASSERTION_FAILURE< \
 106        BOOST_JOIN(boost_static_assert_test_, __LINE__) >)>\
 107          BOOST_JOIN(boost_static_assert_typedef_, __LINE__)
 108 #elif BOOST_WORKAROUND(__MWERKS__, <= 0x3003)
 109 // special version for CodeWarrior <= 8.x
 110 #define BOOST_STATIC_ASSERT( B ) \
 111    BOOST_STATIC_CONSTANT(int, \
 112      BOOST_JOIN(boost_static_assert_test_, __LINE__) = \
 113        sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >) )
 114 #else
 115 // generic version
 116 #define BOOST_STATIC_ASSERT( B ) \
 117    typedef ::boost::static_assert_test<\
 118       sizeof(::boost::STATIC_ASSERTION_FAILURE< BOOST_STATIC_ASSERT_BOOL_CAST( B ) >)>\
 119          BOOST_JOIN(boost_static_assert_typedef_, __LINE__)
 120 #endif
 121
 122 #else
 123 // alternative enum based implementation:
 124 #define BOOST_STATIC_ASSERT( B ) \
 125    enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \
 126       = sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >) }
 127 #endif
 128 #endif // ndef BOOST_HAS_STATIC_ASSERT
 129
 130 #endif // BOOST_STATIC_ASSERT_HPP
 131
 132