Re: [Boost-bugs] [Boost C++ Libraries] #3950: boost::interprocess::mapped_region destructor deletes shm where it shouldn't.

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #3950: boost::interprocess::mapped_region destructor deletes shm where it shouldn't.
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-05-23 09:53:51

#3950: boost::interprocess::mapped_region destructor deletes shm where it
shouldn't.
-------------------------------------------+--------------------------------
 Reporter:  Lénaïc Huard <lhuard@…>        |       Owner:  igaztanaga  
     Type:  Bugs                           |      Status:  new         
Milestone:  Boost 1.43.0                   |   Component:  interprocess
  Version:  Boost 1.42.0                   |    Severity:  Problem     
 Keywords:                                 |  
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Comment(by kab@…):

 Replying to [comment:9 igaztanaga]:
 > I think GCC is right, because the dynamic type of the object is not
 rv<T> but T. We
 > don't create any rv<T> object so downcasting T to a non-existent rv<T>
 object is at
 > least doubtful.

 Ah, I didn't realize that. So there are no objects whose dynamic type is
 rv<T>. That would mean the static downcast is hitting the "undefined
 behavior" case at the end of 5.2.9/8. And if the compiler can figure that
 out (that the T* really can't be an rv<T>*) then it can generate pretty
 much any old garbage code.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3950#comment:10>
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