Re: [Boost-bugs] [Boost C++ Libraries] #10723: UNINIT_CTOR(boost::​multi_index::​detail::​bidir_node_iterator<boost::​multi_index::​detail::​ordered_index_node<boost::​multi_index::​detail::​ordered_index_node<boost::​multi_index does not get initialised)

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #10723: UNINIT_CTOR(boost::​multi_index::​detail::​bidir_node_iterator<boost::​multi_index::​detail::​ordered_index_node<boost::​multi_index::​detail::​ordered_index_node<boost::​multi_index does not get initialised)
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-08-27 19:25:25

#10723: UNINIT_CTOR(boost::​multi_index::​detail::​bidir_node_iterator<boost::
multi_index::​detail::​ordered_index_node<boost::​multi_index::​detail::
ordered_index_node<boost::​multi_index does not get initialised)
----------------------------------------------+-------------------------
  Reporter:  anup kumar <anup.shrivastava@…>  |      Owner:  joaquin
      Type:  Bugs                             |     Status:  closed
 Milestone:  To Be Determined                 |  Component:  multi_index
   Version:  Boost 1.54.0                     |   Severity:  Cosmetic
Resolution:  fixed                            |   Keywords:  UNINIT_CTOR
----------------------------------------------+-------------------------

Comment (by joaquin):

 Hi anonymous,

 The default constructor is needed because it is permissible (and very
 useful) to default initialize an iterator, so we can't just omit this
 constructor. When default-initialized, the iterator has a ''singular''
 value according to the C++ standard terminology in
 '''[iterator.requirements.general]/5'''. Dereferencing a singular value is
 undefined behavior, so the programmer is not allowed to do it regardless
 of whether the value of the pointer is null or not. My reluctance to
 initialize to null comes from the fact that we're introducing a run-time
 penalty in default construction (even if a negligible one) that, in the
 best of cases, will only expose undefined behavior more nicely.

 Anyway, is perhaps the annotation commited in

 https://github.com/boostorg/multi_index/commit/08fe6a360acf99e1732a54ef8b3114455f59116b


 not silencing the Coverity warning?

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/10723#comment:5>
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