Re: [Boost-bugs] [Boost C++ Libraries] #10740: Multi-level containers do not cooperate with address tracking

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #10740: Multi-level containers do not cooperate with address tracking
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2014-11-27 21:57:57

#10740: Multi-level containers do not cooperate with address tracking
-------------------------------------+-------------------------------------
  Reporter:  Simon Etter             |      Owner:  ramey
  <ettersi@…>                        |     Status:  closed
      Type:  Bugs                    |  Component:  serialization
 Milestone:  To Be Determined        |   Severity:  Problem
   Version:  Boost 1.56.0            |   Keywords:  Address tracking, STL
Resolution:  invalid                 |  containers
-------------------------------------+-------------------------------------

Comment (by ramey):

 " Since we would like future pointers to this "logical" object to point to
 &l_.back() and not &tll_, we tell the new address to the archive by
 calling reset_pointer_address(). At this point, the error happens: We
 would also have to tell the archive that we want future pointers to
 reference &l_.back().back() and not &tll_.back(). We cannot do this,
 however, because at this point in the code we don't know that tll_ (which
 corresponds to the variable s in the actual code) is in fact a vector."

 Not quite that simple

 given:
 std::vector<dummy> t1;
 std::vector<std::vector<dummy>> t2(t1)

 ia >> t2
     for each t in t2
         ia >> t
             for each x in t
                 ia >> x
                 resetobjectaddress (x) // moves pointer to everythingf t1
             resetobjectaddress(t) // moves pointers to everything under t2

 note that the addresses in t1 get moved twice !
 std::vector<dummy> t

 So this is pretty subtle - the fact that sometimes it works and sometimes
 it doesn't means it's going to be a bitch to find.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10740#comment:7>
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