What is weak_ptr used for?

By using a weak_ptr , you can create a shared_ptr that joins to an existing set of related instances, but only if the underlying memory resource is still valid. A weak_ptr itself does not participate in the reference counting, and therefore, it cannot prevent the reference count from going to zero.

How is weak_ptr implemented?

To implement weak_ptr , the “counter” object stores two different counters: The “use count” is the number of shared_ptr instances pointing to the object. The “weak count” is the number of weak_ptr instances pointing to the object, plus one if the “use count” is still > 0.

Is weak_ptr thread safe?

Note that the control block used by std::weak_ptr and std::shared_ptr is thread-safe: different non-atomic std::weak_ptr objects can be accessed using mutable operations, such as operator= or reset , simultaneously by multiple threads, even when these instances are copies or otherwise share the same control block …

What is shared_ptr?

The shared_ptr type is a smart pointer in the C++ standard library that is designed for scenarios in which more than one owner might have to manage the lifetime of the object in memory.

What is std :: Owner_less?

This function object provides owner-based (as opposed to value-based) mixed-type ordering of both std::weak_ptr and std::shared_ptr.

Is copying Shared_ptr thread safe?

When you copy a std::shared_ptr in a thread, all is fine. At first to (2). By using copy construction for the std::shared_ptr localPtr, only the control block is used. That is thread-safe.

What is Make_unique?

make_unique prevents the unspecified-evaluation-order leak triggered by expressions like foo(unique_ptr(new X) , unique_ptr(new Y)) . (Following the advice “never say new ” is simpler than “never say new , unless you immediately give it to a named unique_ptr “.)

What is TWeakObjectPtr?

TWeakObjectPtr is the templated version of the generic FWeakObjectPtr. Constructors. Name. Description. TWeakObjectPtr()