how reference type is capture in a closure and the changes of the value type are observed?
Generated on 8/9/2024
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In Swift, when you refer to a local variable in a closure, you capture that variable by reference. This allows changes to the variable to be observed in the original scope and vice versa. If the variable is captured by a non-escaping closure, it doesn't change the lifetime of the variable. The closure can handle this by just capturing a pointer to the variable's allocation.
However, if the variable is captured by an escaping closure, the lifetime of the variable can be extended for as long as the closure is alive. As a result, the variable also has to be heap allocated, and the closure context has to retain a reference to that object. This is because escaping closures can outlive the scope in which they were created, necessitating the use of heap allocation to manage the variable's lifetime.
For more details, you can refer to the session Explore Swift performance (28:18).
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