Re: [Boost-testing] all serialization tests failing with msvc 8.0+

From: Robert Ramey (ramey_at_[hidden])
Date: 2008-04-06 13:56:23

OK I think I've figured out how these things are meant to be used and
have altered boost/serialization/abstract.hpp in accordance with your
suggestion.

But I still get the same error

>>>> // required by smart_cast for compilers not implementing
>>>> // partial template specialization
>>>> BOOST_BROKEN_COMPILER_TYPE_TRAITS_SPECIALIZATION(
>>>> boost::archive::detail::basic_iarchive
>>>> )

The error message follows.  I don't think its related to the is_abstract 
issue above
it just looks that way because of the error message

Robert Ramey

C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(98) : error C2259: 
'boost::archive::detail::basic_oarchive' : cannot instantiate abstract class
        due to following members:
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::tracking_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(60) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::class_name_type &)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(59) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::class_id_reference_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(58) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::class_id_optional_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(57) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::class_id_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(56) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::object_reference_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(55) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::object_id_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(54) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
        'void boost::archive::detail::basic_oarchive::vsave(const 
boost::archive::version_type)' : is abstract
        C:\BoostTrunk\boost/archive/detail/basic_oarchive.hpp(53) : see 
declaration of 'boost::archive::detail::basic_oarchive::vsave'
C:\BoostTrunk\boost/cstdint.hpp(179) : error C2143: syntax error : missing 
';' before 'namespace'
C:\BoostTrunk\boost/cstdint.hpp(179) : error C4430: missing type specifier - 
int assumed. Note: C++ does not support default-int

John Maddock wrote:

>> That's not the way that macro is supposed to be used, it's an
>> internal detail of the type_traits library such that: when defined
>> it evaluates to the compiler intrinsic for the is_abstract trait,
>> boost::is_abstract can simply it's implementation to just be in
>> terms of BOOST_IS_ABSTRACT. However, when there is no compiler
>> intrinsic, then the macro BOOST_IS_ABSTRACT *is not defined*, and
>> boost::is_abstract uses it's own implementation methods.

Its very unclear how this is meant to be used - if indeed it is meant to
be used by library users at all.

>>>> a) Looking through the code in intrinsics.hpp it looks like at some
>>>> point BOOST_IS_ABSTRACT(T) is defined so that is resolves to
>>>> is_polymorphic.  If my understanding of this is correct, its really
>>>> a bad idea.
>>
>> No, but boost::is_abstract<> may equate to is_polymorphic<> if we
>> can't implement is_abstract (but this only applies to old broken
>> compilers).  I seem to remember we had a long discussion about this
>> when is_abstract was reviewed, and this came up as the least-worst
>> solution.

So it silently changes is_abstract to is_polymorphic a few levels down
in very difficult to understand code  - without so indicating to the user?
Makes me wonder what the worst-worst solution was.

Robert Ramey