Re: [Boost-bugs] [Boost C++ Libraries] #3604: Access violation on diamond inheritance

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #3604: Access violation on diamond inheritance
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-04-10 00:18:13

#3604: Access violation on diamond inheritance
----------------------------------+-----------------------------------------
  Reporter:  kondo@…              |       Owner:  ramey         
      Type:  Support Requests     |      Status:  reopened      
 Milestone:  Boost 1.41.0         |   Component:  serialization 
   Version:  Boost 1.40.0         |    Severity:  Not Applicable
Resolution:                       |    Keywords:                
----------------------------------+-----------------------------------------

Comment(by kondo@…):

 I offer additional information.
 I believe that if the virtual inheritance inclusion distinguished
 correctly, static downcast from a virtual base class does not occur
 anymore.

 Because the void cast includes virtual inheritance case, the void cast
 code is dispatched below class.

 void_cast.hpp
 {{{
 template <class Derived, class Base>
 class void_caster_virtual_base :
     public void_caster
 {
     virtual bool has_virtual_base() const {
         return true;
     }
 public:
     virtual void const * downcast(void const * const t) const {
         const Derived * d =
             dynamic_cast<const Derived *>(
                 static_cast<const Base *>(t)
             );
         return d;
     }
     virtual void const * upcast(void const * const t) const {
         const Base * b =
             dynamic_cast<const Base *>(
                 static_cast<const Derived *>(t)
             );
         return b;
     }
     void_caster_virtual_base();
     virtual ~void_caster_virtual_base();
 };
 }}}

 And the void cast use dynamic_cast instead of static_cast.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3604#comment:12>
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