Re: [Boost-bugs] [Boost C++ Libraries] #1315: iterator_adaptor does not work with incomplete Value types

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #1315: iterator_adaptor does not work with incomplete Value types
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-10-13 22:43:23

#1315: iterator_adaptor does not work with incomplete Value types
--------------------------------------+-------------------------------------
  Reporter:  joaquin                  |       Owner:  witt    
      Type:  Feature Requests         |      Status:  new     
 Milestone:  To Be Determined         |   Component:  iterator
   Version:  Boost Development Trunk  |    Severity:  Problem 
Resolution:                           |    Keywords:          
--------------------------------------+-------------------------------------
Changes (by Duncan Exon Smith <duncanphilipnorman@…>):

 * cc: duncanphilipnorman@… (added)

Comment:

 Replying to [comment:6 Laurent Rineau <Laurent.Rineau__boost@…>]:
 > Replying to [comment:3 dave]:
 > > I think your analysis is correct, but my question to you is: why
 should this be considered a bug?
 >
 > It is more a ''feature request'' than a bug. In a software of ours,
 [http://www.cgal.org/ CGAL], we would like to use the features of
 `iterator_facade`, in a scenario alike the one I posted in [comment:1
 comment 1]. It currently works with GNU/g++ (versions 4.1.2 and 4.3.0 at
 least), even if I do not know why, but not with MSVC++Â 8.

 This feature worked in GCC only because of a bug prior to v4.4 (e.g., you
 could use abstract types in v4.3.4).  However, this bug -- to do with the
 intrinsics `__is_abstract` and `__is_pod` -- was fixed:
  http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39475


 GCC v4.4.3 now gives the same as MSVC.  In particular, `iterator_facade<>`
 cannot be used to wrap pointers to abstract types any longer.  With a
 large codebase that accidentally relied on this misbehaviour, we cannot
 upgrade past GCC v4.3 without this feature.

 Does anyone know if
 [http://lists.boost.org/Archives/boost/2007/10/128738.php the workaround
 above] causes any problems?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/1315#comment:7>
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