Definitive Guide to Shared vs Unique vs Weak Pointers

In the last theoretical chapter of our course, we will reinforce all the learned concepts so far to create a comprehensive comparison table. This table will serve as a practical guide to help us select the most suitable smart pointer for various dynamic memory management needs.


	Shared	Unique	Weak
Ownership semantics	Allows multiple pointers to share ownership of an object	Exclusive ownership; only one pointer can own an object	Non-owning pointers; do not affect object lifespan
Construction	Created using `std::make_shared` or `std::shared_ptr`	Created using `std::make_unique` or `std::unique_ptr`	No direct construction; derived from shared pointers
Suitability	Suitable for scenarios requiring shared ownership	Ideal for scenarios that need exclusive ownership	Breaks cyclic dependencies
Use cases	Shared database resource; shared counter object etc.	A database resource owned exclusively by a class; a dynamic counter object exclusive to a class etc.	To represent weak nodes in a graph or linked list; to implement observer patterns
Memory overhead	Higher, due to reference counting for tracking ownership	Lower than shared pointers as no reference counting involved	Negligible overhead; dependent on shared pointer usage
Performance impact	Highest, due to reference counting	Lower, because no reference counting needed	Minimal; just an observer
Copyability	Possible	Not possible	Possible
Assignability	Assignable	Not assignable	Assignable
Memory cleanup	Deallocated when reference count reaches zero	Automatically deallocated when the owning pointer goes out of scope	No effect on object lifespan
Circular references	Possible	Not possible	Not applicable
Exception safety	Safe	Safe	Safe

¿Todo estuvo claro?

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Sección 6. Capítulo 4