How to Prevent Circular Dependencies When Using std::shared_ptr of \'this\'?

std::shared_ptr of "this": Understanding Circular Dependencies

Inheriting from std::enable_shared_from_this is the key to resolving the "std::shared_ptr of this" conundrum. By enabling this, you can invoke .shared_from_this() to obtain a shared pointer to the current object. However, this introduces a potential circular dependency between the parent and child objects.

To address this issue, it's recommended to use std::weak_ptr for the child's reference to the parent. This prevents the formation of strong circular references and protects against resource leaks. The modified code demonstrates how to implement this approach:

<br>class A : public std::enable_shared_from_this<a> {<br>public:</a></p>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:php;toolbar:false">void addChild(std::shared_ptr<B> child) {
    children.push_back(child);
    child->setParent(shared_from_this());
}

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private:

std::list<std::weak_ptr<B>> children;

};

class B {
public:

void setParent(std::shared_ptr<A> parent) {
    this->parent = parent;
}

private:

std::shared_ptr<A> parent;

};

It's important to note that invoking .shared_from_this() requires that the current object is managed by std::shared_ptr at the time of the call. This implies that creating such objects on the stack is no longer possible, and calling .shared_from_this() from a constructor or destructor is generally not recommended.

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