Re: [Boost-bugs] [Boost C++ Libraries] #4044: reset_object_address with library-created objects

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #4044: reset_object_address with library-created objects
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-03-26 23:10:03

#4044: reset_object_address with library-created objects
-------------------------------------------------+--------------------------
 Reporter:  Richard Hazlewood                    |       Owner:  ramey        
     Type:  Bugs                                 |      Status:  new          
Milestone:  Boost 1.43.0                         |   Component:  serialization
  Version:  Boost 1.42.0                         |    Severity:  Problem      
 Keywords:  reset_object_address heap allocated  |  
-------------------------------------------------+--------------------------

Comment(by Richard Hazlewood):

 Okay, I was trying to generalize/test-case.  Here's something closer to
 what I'm really doing (I'm away from the real code, so this is from memory
 ;-) ):

 {{{
 class Whatever
 {
   typedef boost::function<Signature> Func;

   Func m_func;

   ///

   template <typename A>
   void serialize(A &a, const unsigned)
   {
      if (A::is_saving::value)
      {
        FunctionObject *p = m_func.target<FunctionObject>();
        // Let's serialize the function object via pointer
        a & p;
      }
      else
      {
        FunctionObject *p = 0;
        a & p;
        m_func = *p;  // Hand function object to boost::function
        FunctionObject *realp = m_func.target<FunctionObject>();
        a.reset_object_address(realp, p);   // Does not work
        delete p;  // Hence this will ultimately mess things up
                   // (subsequent serialization may land in same address)
      }
   }
 };
 }}}

 Also, I can't do:

 {{{
     {
        a & *m_func.target<FunctionObject>();
     }
     else
     {
        m_func = FunctionObject(); // Initialize boost::function with empty
 object
        FunctionObject *realp = m_func.target<FunctionObject>();
        a & *realp;  // Deserialize right in
      }
 }}}

 Because the {{{FunctionObject}}} has a private default ctor.  This is why
 I was trying to route it through the serialization library's pointer
 creation ({{{FunctionObject}}} has ''access'' friendship).

 Further, this is a simplification.  In the real code {{{FunctionObject}}}
 is a template argument, but it ''is'' serializable.

 Hope this is clearer.
 Best...

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4044#comment:2>
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