[Boost-bugs] [Boost C++ Libraries] #4565: Stream operator overload for thread::id fails because thread::id::print() is not const.

Subject: [Boost-bugs] [Boost C++ Libraries] #4565: Stream operator overload for thread::id fails because thread::id::print() is not const.
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2010-08-18 17:29:49

#4565: Stream operator overload for thread::id fails because thread::id::print()
is not const.
-------------------------------------------------------+--------------------
 Reporter:  David Larsson <david.larsson@…>            |       Owner:  anthonyw
     Type:  Bugs                                       |      Status:  new     
Milestone:  To Be Determined                           |   Component:  thread  
  Version:  Boost 1.44.0                               |    Severity:  Problem 
 Keywords:                                             |  
-------------------------------------------------------+--------------------
 In Boost 1.44.0 the implementation of `operator<<( basic_stream &,
 thread::id const & )` changed when `BOOST_NO_MEMBER_TEMPLATE_FRIENDS` is
 defined to call a new member function `print()`. However,
 `thread::id::print()` is not `const`, so the following (admittedly silly)
 code fragment will not compile:

 {{{
 std::cout << thread::current_thread::id() << std::endl;
 }}}

 On VC8 it fails with the error ''boost/thread/detail/thread.hpp(473) :
 error C2662: 'std::basic_ostream<_Elem,_Traits>
 &boost::thread::id::print<char,std::char_traits<char>>(std::basic_ostream<_Elem,_Traits>
 &)' : cannot convert 'this' pointer from 'const boost::thread::id' to
 'boost::thread::id &'''.

 The fix should be trivial - simply add a `const` modifier to
 `boost::id::print`. On a related note, it seems a bit strange that the
 public method `print()` only is defined for legacy compilers that have
 `BOOST_NO_MEMBER_TEMPLATE_FRIENDS`. It should be private or exist for all
 compilers. Finally, the code that failed is a workaround that is enabled
 for VC8 and earlier, but the stream operator worked for `thread::id` on
 VC8 before the workaround in Boost 1.43. Is it really necessary to define
 `BOOST_NO_MEMBER_TEMPLATE_FRIENDS` for VC8 (VS2005)?

 Thanks for a great library,

 ''/ David''

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/4565>
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