How do you make a weak pointer?

You can make a weak pointer from a shared pointer, just using assignment = e.g. bool release_channel(std::shared_ptr ch) { std::weak_ptr weak_ch = ch; //… }

What is a weak reference in C++?

From Wikipedia, the free encyclopedia. In computer programming, a weak reference is a reference that does not protect the referenced object from collection by a garbage collector, unlike a strong reference.

Can you dereference a weak pointer?

The nice trick around weak_ptr is that they are not dereferenceable. Instead, to access the object you call lock() that atomically returns a shared_ptr that points to the object, or to null if not available.

Can weak_ptr be copied?

Throws: nothing. template weak_ptr(shared_ptr const & r); weak_ptr(weak_ptr const & r); template weak_ptr(weak_ptr const & r); Effects: If r is empty, constructs an empty weak_ptr; otherwise, constructs a weak_ptr that shares ownership with r as if by storing a copy of the pointer stored in r.

Why do we need weak pointer?

A weak pointer is a smart pointer that does not take ownership of an object but act as an observer. In other words, it does not participate in reference counting to delete an object or extend its lifetime. Weak pointers are mainly used to break the circular dependency that shared pointers create.

When would you use a weak pointer?

The example illustrates how a weak pointer works and is useful when an object needs to be an outside observer, but does not want the responsibility of sharing ownership. This is particularly useful in the scenario that two objects need to point to each other (a.k.a. a circular reference).

What is a weak object?

A weak “or” relation is an ordered collection of references to objects, that keeps all objects from being garbage-collected as long as one of them is still alive. In other words, each of them keeps all others among them from being garbage-collected.

How does a weak reference work?

A weakly referenced object is cleared by the Garbage Collector when it’s weakly reachable. Weak reachability means that an object has neither strong nor soft references pointing to it. The object can be reached only by traversing a weak reference.

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