[Boost-bugs] [Boost C++ Libraries] #7381: C++11 compliance: unresolved symbol when assigning a constexpr duration to a non-const local variable

Subject: [Boost-bugs] [Boost C++ Libraries] #7381: C++11 compliance: unresolved symbol when assigning a constexpr duration to a non-const local variable
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2012-09-16 07:56:24

#7381: C++11 compliance: unresolved symbol when assigning a constexpr duration to
a non-const local variable
------------------------------+---------------------------------------------
 Reporter:  viboes            |       Owner:  viboes 
     Type:  Bugs              |      Status:  new    
Milestone:  To Be Determined  |   Component:  thread 
  Version:  Boost 1.51.0      |    Severity:  Problem
 Keywords:                    |  
------------------------------+---------------------------------------------
 When assigning a template static value member of type constexpr
 boost::chrono::duration to a non-const local variable

 {{{

 template <int Val, typename Type>
 struct dummy
 {
   typedef Type type;
   static constexpr type value{static_cast<type>(Val)};
 };

 void aTest(){
    auto z3 = dummy2<7,boost::chrono::hours>::value;
 }

 }}}

 There is an unresolved symbol link error.

 The reason is that the boost::chrono::duration copy constructor must be
 =default on c++11 so that the type can be used as a constexpr.

 Removing the following declaration in boost/chrono/duration

 {{{
   BOOST_CONSTEXPR duration(const duration& rhs) : rep_(rhs.rep_) {} // =
 default;
 }}}

 solves the issue.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/7381>
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