boost/static_assert.hpp
// (C) Copyright John Maddock 2000. // Use, modification and distribution are subject to the // Boost Software License, Version 1.0. (See accompanying file // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) // See http://www.boost.org/libs/static_assert for documentation. /* Revision history: 02 August 2000 Initial version. */ #ifndef BOOST_STATIC_ASSERT_HPP #define BOOST_STATIC_ASSERT_HPP #include <boost/config.hpp> #include <boost/detail/workaround.hpp> #ifdef __BORLANDC__ // // workaround for buggy integral-constant expression support: #define BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS #endif namespace boost{ // HP aCC cannot deal with missing names for template value parameters template <bool x> struct STATIC_ASSERTION_FAILURE; template <> struct STATIC_ASSERTION_FAILURE<true> { enum { value = 1 }; }; // HP aCC cannot deal with missing names for template value parameters template<int x> struct static_assert_test{}; } // // Implicit instantiation requires that all member declarations be // instantiated, but that the definitions are *not* instantiated. // // It's not particularly clear how this applies to enum's or typedefs; // both are described as declarations [7.1.3] and [7.2] in the standard, // however some compilers use "delayed evaluation" of one or more of // these when implicitly instantiating templates. We use typedef declarations // by default, but try defining BOOST_USE_ENUM_STATIC_ASSERT if the enum // version gets better results from your compiler... // // Implementation: // Both of these versions rely on sizeof(incomplete_type) generating an error // message containing the name of the incomplete type. We use // "STATIC_ASSERTION_FAILURE" as the type name here to generate // an eye catching error message. The result of the sizeof expression is either // used as an enum initialiser, or as a template argument depending which version // is in use... // Note that the argument to the assert is explicitly cast to bool using old- // style casts: too many compilers currently have problems with static_cast // when used inside integral constant expressions. // #if !defined(BOOST_BUGGY_INTEGRAL_CONSTANT_EXPRESSIONS) && \ !BOOST_WORKAROUND(__MWERKS__, < 0x3003) #if defined(BOOST_MSVC) && (BOOST_MSVC < 1300) // __LINE__ macro broken when -ZI is used see Q199057 // fortunately MSVC ignores duplicate typedef's. #define BOOST_STATIC_ASSERT( B ) \ typedef ::boost::static_assert_test<\ sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >)\ > boost_static_assert_typedef_ #elif defined(BOOST_MSVC) #define BOOST_STATIC_ASSERT( B ) \ typedef ::boost::static_assert_test<\ sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >)>\ BOOST_JOIN(boost_static_assert_typedef_, __COUNTER__) #elif defined(BOOST_INTEL_CXX_VERSION) // agurt 15/sep/02: a special care is needed to force Intel C++ issue an error // instead of warning in case of failure # define BOOST_STATIC_ASSERT( B ) \ typedef char BOOST_JOIN(boost_static_assert_typedef_, __LINE__) \ [ ::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >::value ] #elif defined(__sgi) // special version for SGI MIPSpro compiler #define BOOST_STATIC_ASSERT( B ) \ BOOST_STATIC_CONSTANT(bool, \ BOOST_JOIN(boost_static_assert_test_, __LINE__) = ( B )); \ typedef ::boost::static_assert_test<\ sizeof(::boost::STATIC_ASSERTION_FAILURE< \ BOOST_JOIN(boost_static_assert_test_, __LINE__) >)>\ BOOST_JOIN(boost_static_assert_typedef_, __LINE__) #else // generic version #define BOOST_STATIC_ASSERT( B ) \ typedef ::boost::static_assert_test<\ sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >)>\ BOOST_JOIN(boost_static_assert_typedef_, __LINE__) #endif #else // alternative enum based implementation: #define BOOST_STATIC_ASSERT( B ) \ enum { BOOST_JOIN(boost_static_assert_enum_, __LINE__) \ = sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( B ) >) } #endif #endif // BOOST_STATIC_ASSERT_HPP