Re: [boost] Header ordering [was: Vector of Polymorphic Pointers]

From: Robert Ramey (ramey_at_[hidden])
Date: 2006-05-03 00:14:55

I've given a quick look at your post and attachtment.

I vividly recall the making several attempts to get BOOST...EXPORT
to compile - then to instantiate code.  In fact, even those efforts
were not entirely successful - CW still can't handle it.  Then there
was a final round getting it past two phase lookup.  So as much
as I would like to see this last header dependency eliminated, I think
it would take a lot more time than it would first appear.  And
right now I don't have the time required even to address higher
priority issues.

Robert Ramey

David Abrahams wrote:
>> "Robert Ramey" <ramey_at_[hidden]> writes:
>>
>>> This is explained in the docmentation under
>>>
>>> Reference/Special Considerations/Exporting Class Serialization
>>>
>>> Robert Ramey
>>
>> I have analyzed your issue and I believe there is a better way; one
>> that avoids the header ordering requirement.  I have put together a
>> small demonstration, which is enclosed.  This shows that we can
>> instantiate a class template (instantiator) for the exported class
>> and
>> each archive that's been seen.
>>
>> Then the only challenge is causing that class template instantiation
>> to actually instantiate executable code.  Fortunately, I've recently
>> addressed that problem in changes to the serialization library.  The
>> basics are in CVS at:
>>
>>  boost/boost/concept/detail/general.hpp
>>  boost/boost/concept/detail/msvc.hpp
>>  boost/boost/concept/detail/borland.hpp
>>
>> (Ignore the part that says BOOST_OLD_CONCEPT_SUPPORT), so we have the
>> technology.  And if you use the function pointer technique of
>> BOOST_CONCEPT_ASSERT(( ... )) in boost/boost/concept/assert.hpp
>> you'll
>> be able to use BOOST_CLASS_EXPORT on class template instances with
>> multiple arguments.
>>
>>  BOOST_CLASS_EXPORT(foo<bar,baz>)  // an error, today.
>>
>> I hope all this is helpful.
>>
>>
>
>
>
>>
>> --
>> Dave Abrahams
>> Boost Consulting
>> www.boost-consulting.com
>>
>
>
>
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