Unique_ptr vs. Shared_ptr: What are their Key Differences in Resource Management?

Unique_ptr vs. Shared_ptr

Question:

What are the fundamental differences between unique_ptr and shared_ptr?

Answer:

Both unique_ptr and shared_ptr are smart pointers that automatically manage the allocation and deallocation of objects. The key distinction lies in their handling of multiple pointers to the same resource.

Unique_ptr

• Allows only one unique_ptr to point to a resource at any given time.
• When the unique_ptr is destroyed, the resource it points to is automatically freed.
• Copying or assigning a unique_ptr results in a compile-time error, as only one pointer should have ownership.
• Moving a unique_ptr transfers ownership to the new unique_ptr, allowing the moved resource to be released when the new owner is destroyed.

Shared_ptr

• Allows multiple shared_ptrs to point to the same resource.
• When the last shared_ptr referencing a resource is destroyed, the resource is deallocated.
• Copying or assigning a shared_ptr creates another independent reference to the same resource, which increases the reference count.
• Reference counting ensures that the resource remains alive as long as at least one shared_ptr exists.

Summary

Unique_ptr is suitable when you want exclusive ownership and control over a single resource. Shared_ptr is appropriate when multiple entities require access to a shared resource, with proper management of reference cycles to avoid memory leaks.

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