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