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C++ Smart Pointers

bookCircular 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

main.cpp

copy

              
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#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.

question mark

What problem does a circular reference cause in std::shared_ptr?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 3

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bookCircular References and Shared Pointers

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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

main.cpp

copy

              
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.

question mark

What problem does a circular reference cause in std::shared_ptr?

Select the correct answer

Var allt tydligt?

Hur kan vi förbättra det?

Tack för dina kommentarer!

Avsnitt 3. Kapitel 3
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