Do vector elements need to be movable?
c++, c++11, stdvector
Solution
According to 23.3.6.2 [vector.cons] paragraph 4 the constructor you are using requires `DefaultInsertable`. Since the constructor isn't one of the constructors for the requirements table also asking for `CopyInsertable` there shouldn't be any additional requirements. According to 23.2.1 [container.requirements.general] paragraph 13, `DefaultInsertable` means that the following expression is well-formed:
allocator_traits<A>::construct(m, p);
It seems, this means that the answer depends on the used allocator `A`. I don't quite fancy to analyze the deeper meaning of 20.6.7.2 [allocator.uses.construction]. Let's do the instructor escape: Determining what this paragraph means is left as an exercise!
Problem
I noticed that requirements of std::vector on its elememt type T changed from C++03 to C++0x. T now does not need to be copy constructible anymore, but move constructibility suffices. Is it required for T even if we don't potentially reallocate? ``` vector<boost::scoped_ptr<int>> x(numberElements); ``` I don't see a need for a move here. What does the specification say?