Re: [Boost-users] [serialization] Problems with BOOST_IS_ABSTRACT, gcc 3.2.3 and Boost 1.35.0

From: Dan Thomas (dan_at_[hidden])
Date: 2008-07-21 06:20:12

>> If I use gcc 3.2.3 (Linux) and Boost 1.35.0 to compile the example 
>> program at...
>>   http://lists.boost.org/boost-users/att-26574/test_serialize.cpp
>>  ...I get extensive compile errors which I can summarise as:
>>     <path>/boost_1_35_0/boost/serialization/export.hpp:125:
>>        `instantiate'
>>     is not a member of type
>> 
>> `boost::archive::detail::ptr_serialization_support<boost::archive::text_iarchive, 
>> base>'
>>
>> These errors do not occur if I use either Boost 1.33.0 or Microsoft 
>> Visual Studio.
>>
>> The fact that the test program's base class is abstract seems to be 
>> central to the problem. The error
>> is eliminated if I remove the BOOST_IS_ABSTRACT(base) statement from the 
>> test program. Doing
>> so naturally causes other problems but these are in turn fixed by making 
>> "base" concrete i.e. by
>> removing the =0 qualifier from base::get_id() and providing an 
>> implementation.
>>
>> It looks as if code in Boost 1.35.0 expects all classes to provide an 
>> instantiate method, even though
>> the method is not in fact present on classes that have been marked as 
>> abstract. Is there any chance
>> of a fix or work-around?

> I"m not sure what the problem is here.
>
> In 1.36 (and the trunk) we've made some alterations and fixed things in 
> this area.

I've just downloaded the head version of 1.36 and tried that but hit very 
similar problems. In more detail...

I took http://lists.boost.org/boost-users/att-26574/test_serialize.cpp and 
modified it by changing
   #include <boost/serialization/is_abstract.hpp>
to
   #include <boost/type_traits/is_abstract.hpp>
And
   BOOST_IS_ABSTRACT(base);
to
   BOOST_SERIALIZATION_ASSUME_ABSTRACT(base);

The result compiles OK with MSVC 8.0 but generates two errors on gcc 3.2.3:
   <path>/boost_1_36_0/boost/serialization/export.hpp:98:
      `instantiate' is not a member of type
      `boost::archive::detail::ptr_serialization_support<boost::archive::text_oarchive, 
derived>'
   <path>/boost_1_36_0/boost/serialization/export.hpp:98:
      `instantiate' is not a member of type
      `boost::archive::detail::ptr_serialization_support<boost::archive::text_iarchive, 
derived>'
In other words, the same error as before but affecting different classes.

I should also say that although I am using a stock test program to 
demonstrate this problem, it also affects the real code that I am writing - 
the issue is not just academic.

Thanks

Dan