Circular References and Shared Pointers

When working with std::shared_ptr, you might encounter an issue known as a circular reference. A circular reference occurs when two objects hold shared_ptr references to each other. Since shared_ptr uses reference counting, the count never reaches zero, causing a memory leak.

main.cpp


              1234567891011121314151617181920212223242526
            
#include <iostream>
#include <memory>

class B; // Forward declaration

class A {
public:
    std::shared_ptr<B> p_b;
    ~A() { std::cout << "A destroyed\n"; }
};

class B {
public:
    ~B() { std::cout << "B destroyed\n"; }

    std::shared_ptr<A> p_a;
};

int main() 
{
    std::shared_ptr<A> a = std::make_shared<A>();
    std::shared_ptr<B> b = std::make_shared<B>();

    a->p_b = b;
    b->p_a = a;
}

There is a way to fix this issue you need to use a different type of smart pointer.

Tutto è chiaro?

Grazie per i tuoi commenti!

Sezione 3. Capitolo 3

Chieda ad AI

Chieda pure quello che desidera o provi una delle domande suggerite per iniziare la nostra conversazione

Contenuti del Corso

C++ Smart Pointers

1. Introduction to Smart Pointers

Understanding Pointers Dynamic memory allocation The Need For Smart Pointers

2. Unique Pointers

Introduction to Unique Pointers Moving Unique Pointers Application For Unique Pointers Passing Around Unique Pointers Methods of a Unique Pointer

3. Shared Pointers

Introduction to Shared Pointers Creating and Sharing Shared Pointers Circular References and Shared Pointers

4. Weak Pointers

Introduction to Weak Pointers Creating And Using Weak Pointers Breaking Circular References With Weak Pointers Important Weak Pointer Functions

5. Advanced topics