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

Subject: [Boost-bugs] [Boost C++ Libraries] #11032: boost::offset_ptr needs explicit ctor
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-02-16 14:38:13

#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
 Keywords:                    |
------------------------------+--------------------------
 Both the libc++ std library implementation and the MSVC library
 implementation require that their pointer types can be upcast.

 The list and tree data structures have a class hierarchy of node types and
 often seem to pass pointers to the base types (or to offset_ptr<void>)
 that are then upcast to the most derived types. offset_ptr has no explicit
 constructor that allows upcasts, only implicit ctors for downcasts.

 We have patched our version of offset_ptr with this constructor:

 {{{
 //!Explicit constructor from other offset_ptr. Never throws.
 template<class T2>
 explicit offset_ptr(const offset_ptr<T2, DifferenceType, OffsetType,
 OffsetAlignment> &ptr
    , typename ipcdetail::enable_if_c<
    !ipcdetail::is_convertible<T2*, PointedType*>::value
     >::type * = 0)
     :
 internal(ipcdetail::offset_ptr_to_offset<OffsetType>(static_cast<PointedType*>(ptr.get()),
 this))
  {}

 }}}

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