Swift: Developing iOS Applications

Creating strong reference cycles with closures

Earlier in this chapter, we said, "the best thing is, for the most part, Swift will handle the memory management for us". The "for the most part" section of the quote means that if everything is written in a standard way, Swift will handle the memory management of the closures for us. However, just like classes, there are times where the memory management fails us. Memory management will work correctly for all of the examples that we have seen in this chapter so far. It is possible to create a strong reference cycle that would prevent Swift's memory management from working correctly. Let's look at what happens if we create a strong reference cycle with closures.

A strong reference cycle may happen ...