How to create map of scoped_ptr in c++

Question

I have the following code and line 2 gives me an error during compilation. Is it possible to create a map of scoped pointers or do I have to use shared pointers instead?

map<int, scoped_ptr> mp;
mp[1] = scoped_ptr(new obj());

error:

boost::scoped_ptr<T>& boost::scoped_ptr<T>::operator=(const boost::scoped_ptr<T>&) [with T = ]’ is private

Answer 1

You can't, boost::scoped_ptr is non-copyable by design (emphasis mine):

The scoped_ptr template is a simple solution for simple needs. It supplies a basic "resource acquisition is initialization" facility, without shared-ownership or transfer-of-ownership semantics. Both its name and enforcement of semantics (by being noncopyable) signal its intent to retain ownership solely within the current scope.

<...>

scoped_ptr cannot be used in C++ Standard Library containers. Use shared_ptr if you need a smart pointer that can.

You can, however, emplace shared_ptrs into a container, since in this case no copying is performed:

std::list<boost::scoped_ptr<MyClass>> list;
list.emplace_back(new MyClass());