Re: [Boost-bugs] [Boost C++ Libraries] #11032: boost::offset_ptr needs explicit ctor

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #11032: boost::offset_ptr needs explicit ctor
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-03-12 09:21:24

#11032: boost::offset_ptr needs explicit ctor
-------------------------------+--------------------------
  Reporter:  stheophil@…       |      Owner:  igaztanaga
      Type:  Bugs              |     Status:  new
 Milestone:  To Be Determined  |  Component:  interprocess
   Version:  Boost 1.57.0      |   Severity:  Problem
Resolution:                    |   Keywords:
-------------------------------+--------------------------

Comment (by stheophil@…):

 Yes, I  want it to support downcasting. Sorry.

 {{{
 offset_ptr<Base> pb = ...; offset_ptr<Derived>pd(pb);
 }}}

 Does not have to compile because, as you say, raw pointers do not support
 this conversion, but
 {{{
 offset_ptr<Base> pb = ...; offset_ptr<Derived>pd =
 static_cast<offset_ptr<Derived>>(pb);
 }}}

 should compile and by consequence

 {{{
 offset_ptr<Base> pb = ...; offset_ptr<Derived>pd =
 (offset_ptr<Derived>)pb;
 }}}

 too, which just does a static_cast if I understand correctly. Both are
 used a lot in std::list and std::map implementations of Clang and MSVC.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11032#comment:2>
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