[boost] Ominous Warning — should I be worried?

23 Dec 2013


      I'm compiling with VS10, and using Boost 1.49.0
“reference member is initialized to a temporary that doesn't persist after the constructor 
exits”
That does not sound good, and browsing through the mailing list archives I see discussions 
of regressions in 2010 that cite C4413 and use of emplace.
I can't read the source code because it's just a ball of preprocessor stuff.  Is this a 
real problem or a warning that can be ignored?  I would think that if Boost.Container was 
broken on VS10, it would be mentioned somewhere where it's easy to spot.

Thanks,
—John

E:\boost_1_49\boost/preprocessor/iteration/detail/local.hpp(37): warning C4413: 
'boost::container::container_detail::advanced_insert_aux_non_movable_emplace1arg<A,Iterator,P0>::m_p0' 
: reference member is initialized to a temporary that doesn't persist after the 
constructor exits
           with
           [
A=std::allocator<std::tr1::shared_ptr<MyTypeA>>,
               Iterator=std::tr1::shared_ptr<MyTypeA> *,
               P0=std::tr1::shared_ptr<MyTypeA>
           ]
E:\boost_1_49\boost/preprocessor/iteration/detail/local.hpp(37) : see declaration of 
'boost::container::container_detail::advanced_insert_aux_non_movable_emplace1arg<A,Iterator,P0>::m_p0'
           with
           [
A=std::allocator<std::tr1::shared_ptr<MyTypeA>>,
               Iterator=std::tr1::shared_ptr<MyTypeA> *,
               P0=std::tr1::shared_ptr<MyTypeA>
           ]
E:\boost_1_49\boost/preprocessor/iteration/detail/local.hpp(37) : while compiling class 
template member function 
'boost::container::container_detail::advanced_insert_aux_non_movable_emplace1arg<A,Iterator,P0>::advanced_insert_aux_non_movable_emplace1arg(A 
&,P0 &&)'
           with
           [
A=std::allocator<std::tr1::shared_ptr<MyTypeA>>,
               Iterator=std::tr1::shared_ptr<MyTypeA> *,
               P0=std::tr1::shared_ptr<MyTypeA>
           ]
E:\boost_1_49\boost/preprocessor/iteration/detail/local.hpp(37) : see reference to class 
template instantiation 
'boost::container::container_detail::advanced_insert_aux_non_movable_emplace1arg<A,Iterator,P0>' 
being compiled
           with
           [
A=std::allocator<std::tr1::shared_ptr<MyTypeA>>,
               Iterator=std::tr1::shared_ptr<MyTypeA> *,
               P0=std::tr1::shared_ptr<MyTypeA>
           ]
E:\boost_1_49\boost/preprocessor/iteration/detail/local.hpp(37) : see reference to class 
template instantiation 
'boost::container::container_detail::advanced_insert_aux_emplace1arg<A,Iterator,P0>' being 
compiled
           with
           [
A=std::allocator<std::tr1::shared_ptr<MyTypeA>>,
               Iterator=std::tr1::shared_ptr<MyTypeA> *,
               P0=std::tr1::shared_ptr<MyTypeA>
           ]
           mysourcefile.cpp(172) : see reference to function template instantiation 'void 
boost::container::vector<T>::emplace_back<std::tr1::shared_ptr<_Ty>>(P0 &&)' being compiled
           with
           [
               T=std::tr1::shared_ptr<MyTypeA>,
               _Ty=MyTypeA,
               P0=std::tr1::shared_ptr<MyTypeA>
           ]

[boost] Ominous Warning — should I be worried?

John M. Dlugosz