Re: [Boost-bugs] [Boost C++ Libraries] #2508: Serialization emits lots of warnings for MSVC7.1 (non-polymorphic / shared_ptr)

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #2508: Serialization emits lots of warnings for MSVC7.1 (non-polymorphic / shared_ptr)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-07-30 13:38:50

#2508: Serialization emits lots of warnings for MSVC7.1 (non-polymorphic /
shared_ptr)
----------------------------------------------------------+-----------------
 Reporter:  Chard                                         |       Owner:  ramey        
     Type:  Bugs                                          |      Status:  assigned     
Milestone:  Boost 1.38.0                                  |   Component:  serialization
  Version:  Boost 1.36.0                                  |    Severity:  Problem      
 Keywords:  non-polymorphic shared_ptr warnings MSVC 7.1  |  
----------------------------------------------------------+-----------------

Comment(by Chard):

 In class: extended_type_info_typeid

 Function:

 {{{
     const extended_type_info *
     get_derived_extended_type_info(const T & t) const {
         // note: this implementation - based on usage of typeid (rtti)
         // only does something if the class has at least one virtual
 function.
         BOOST_STATIC_WARNING(boost::is_polymorphic<T>::value);
         return
             detail::extended_type_info_typeid_0::get_extended_type_info(
                 typeid(t)
             );
     }
 }}}

 The 'warning' that the class should be polymorphic is incorrect, as
 illustrated by this issue.

 The reason this issue has not shown itself to gcc users is that the gcc
 static warning macro does not appear to work.

 We've investigated the division-by-zero method (for gcc 3.3), and it
 appears that gcc doesn't bother stamping out the "struct
 STATIC_WARNINGxxxx".  By declaring an actual instance of the
 STATIC_WARNINGxxxx struct and then calling the f() method on it, the
 warnings then start trailing out…

 In this case, MSVC71 is doing the 'right thing'.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/2508#comment:3>
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