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I have a vector of unique_ptr's and I want to append them to another vector of unique_ptrs. I would normally do a simple insert:

std::vector<std::unique_ptr<foo>> bar;
bar.push_back(std::unique_ptr<foo>(new foo(1)));
std::vector<std::unique_ptr<foo>> baz;
baz.push_back(std::unique_ptr<foo>(new foo(2)));
bar.insert(bar.end(), baz.begin(), baz.end());
However this gives me compile errors similar to this:
/usr/include/c++/4.8/bits/stl_algobase.h:335: error: use of deleted function 'std::unique_ptr<_Tp, _Dp>& std::unique_ptr<_Tp, _Dp>::operator=(const std::unique_ptr<_Tp, _Dp>&) [with _Tp = foo; _Dp = std::default_delete<foo>]'
    *__result = *__first;
Is there a convenient way to insert or do I have to iterate over baz and push_back on bar?  I'm currently using gcc 4.8.1.
Thanks
unique_ptr is not assignable with normal assignment operator (the error says it's deleted). You can only move them:
bar.insert(bar.end(),
    std::make_move_iterator(baz.begin()),
    std::make_move_iterator(baz.end())
Of course, this transfers the ownership of the managed object and original pointers will have nullptr value.
                That's probably a better answer than mine, since it allows the vector to reserve enough space before moving.
– Mike Seymour
                Jan 31, 2014 at 18:53
                Actually unique_ptr is one of the few types that has a specified moved-from state:  nullptr.  Otherwise the contract of unique ownership could not be held.
– Howard Hinnant
                Feb 1, 2014 at 0:38
        
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