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    <p>You allocate your Server and Client instances on the stack, and they will be deleted when <code>main()</code> exits. You don't want <code>std::shared_ptr</code> deleting them as well. Thus, there are two solutions:</p> <ol> <li><p>Use unmanaged pointers within Client and Server, and manage their lifetimes externally.</p></li> <li><p>Use managed pointers everywhere, including <code>main()</code>. Do note that <code>shared_ptr</code> implies ownership. In the current design, a Server owns the client, but also a Client owns the server. That's a circular reference: by default, they'll never be freed, unless you reset one of those pointers while you still can.</p> <p>As an example, you can decide that the clients keep the server alive, thus last vanishing client will bring down the server if there are no other shared_ptrs pointing at it. The server would have a <code>weak_ptr</code> to the client(s), but the clients would have a <code>shared_ptr</code> to the server.</p></li> </ol> <pre><code>class Client; class Server; class Client { public: void SetServer (const std::shared_ptr&lt;const Server&gt; &amp;server); private: std::shared_ptr&lt;const Server&gt; server; }; void Client::SetServer (const std::shared_ptr&lt;const Server&gt; &amp;server) { this-&gt;server = server; } class Server { public: void SetClient (const std::weak_ptr&lt;const Client&gt; &amp;client); private: std::weak_ptr&lt;const Client&gt; client; }; void Server::SetClient (const std::weak_ptr&lt;const Client&gt; &amp;client) { this-&gt;client = client; } int main() { std::shared_ptr&lt;Server&gt; server(new Server); std::shared_ptr&lt;Client&gt; client(new Client); server-&gt;SetClient(client); client-&gt;SetServer(server); // do stuff return 0; } </code></pre>
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    1. USKuba Ober
    1. USKuba Ober
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    1. CO+1. The important thing is to keep in mind that you surrender the responsibility for deletion of the object pointed by what you used to construct the `std::shared_ptr`.
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      1. USBalint
    2. COYou can't construct a `weak_ptr` from a raw pointer. You can only construct a `weak_ptr` from a `shared_ptr` or another `weak_ptr`.
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      1. USBenjamin Lindley
    3. CO@KubaOber Yeah, that's really nice and it seems to work. Thanks! Unfortunately, I feel stupid to just plug&play code that I do not understand properly. Could you please elaborate on the details, like, for example what happens behind the curtains and why use `std::weak_ptr`? What dictates the order in which the pointers get released and the destructors get called? If we are to assume that the server is and always will be just one, my common sense tells me that I should be using an `std::unique_ptr` instead.
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      1. USMihai Todor
 

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