How does a reference-counting smart pointer's reference counting work?

Question

In other words, how does the implementation keeps track of the count?

Is there a map-like object maintained which is accessible by all the shared_ptr in

Answer 1

As far as I remember, there was the problem of reference counting pointer treated in a chapter of Effective C++.

In principle, you have the "light" pointer class, containing a pointer to a class holding the reference which knows to increment/decrement reference and destroy the pointer object. That reference counting class points to the object to be referenced.