Re: [Boost-bugs] [Boost C++ Libraries] #6655: Inclusion of <boost/signals2.hpp> causes valid code to fail to compile with Clang

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #6655: Inclusion of <boost/signals2.hpp> causes valid code to fail to compile with Clang
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-03-06 11:40:11

#6655: Inclusion of <boost/signals2.hpp> causes valid code to fail to compile with
Clang
----------------------------------------------------------+-----------------
  Reporter:  Alexander Korsunsky <fat.lobyte9@…>          |       Owner:  fmhess  
      Type:  Bugs                                         |      Status:  new     
 Milestone:  Boost 1.50.0                                 |   Component:  signals2
   Version:  Boost 1.49.0                                 |    Severity:  Problem 
Resolution:                                               |    Keywords:          
----------------------------------------------------------+-----------------

Comment (by Michel Morin <mimomorin@…>):

 > The header boost/signals2/detail/foreign_ptr.hpp declares two names in
 the std:: namespace
 > which is undefined behaviour, according to the Standard 17.6.4.2.1

 Yep. It's not standard-conforming to forward-declare the standard library
 types
 (though some standard libraries allow it).
 `libc++` uses an inline namespace, and so forward declarations in
 namespace `std`
 causes compile errors.

 [[BR]]
 > Please remove the offending lines from the header.
 The solution is to remove the forward declarations and to include
 `<memory>`.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/6655#comment:1>
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