[Boost-bugs] [Boost C++ Libraries] #3822: boost/asio/buffer.hpp MSVC workaround is inaccurately targeted

Subject: [Boost-bugs] [Boost C++ Libraries] #3822: boost/asio/buffer.hpp MSVC workaround is inaccurately targeted
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-01-06 00:57:14

#3822: boost/asio/buffer.hpp MSVC workaround is inaccurately targeted
----------------------------------------------------+-----------------------
 Reporter:  Stephan T. Lavavej <stl@…>              |       Owner:  chris_kohlhoff
     Type:  Bugs                                    |      Status:  new           
Milestone:  Boost 1.42.0                            |   Component:  asio          
  Version:  Boost 1.41.0                            |    Severity:  Problem       
 Keywords:                                          |  
----------------------------------------------------+-----------------------
 This was reported to Microsoft as a bug in VC10 Beta 2 (see
 http://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=522096

 ), but is actually a bug in Boost.Asio, caused by an inaccurately targeted
 workaround for a bug in VC8!

 The offending code is in boost/asio/buffer.hpp :

   ~buffer_debug_check()
   {
 #if BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
     // MSVC's string iterator checking may crash in a
 std::string::iterator
     // object's destructor when the iterator points to an already-
 destroyed
     // std::string object, unless the iterator is cleared first.
     iter_ = Iterator();
 #endif // BOOST_WORKAROUND(BOOST_MSVC, >= 1400)
   }

 The bug mentioned by the comment affected only VC8 (_MSC_VER == 1400). VC9
 RTM and later are unaffected, as I fixed this bug in VC9 RTM. Therefore,
 the BOOST_WORKAROUND should check for == 1400, not >= 1400.

 (This workaround uses a singular iterator as the source of an assignment,
 which triggers undefined behavior. This crashes VC10 Beta 2 due to the
 extensive changes we made in the STL. It should probably trigger an assert
 dialog - I've made a note to myself about that. But in any event, a
 conformant implementation is allowed to explode when it sees this. I
 believe the workaround is correct for VC8, and it appears to be harmless
 for VC9, but restricting it to VC8 would be ideal.)

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3822>
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