# Friday Q&A 2017-09-22: Swift 4 Weak References

DevFeed: [Friday Q&A 2017-09-22: Swift 4 Weak References](<https://devfeed.tech/articles/friday-q-a-2017-09-22-swift-4-weak-references-30622.md>)

Original publisher: [Read original article](<http://www.mikeash.com/pyblog/friday-qa-2017-09-22-swift-4-weak-references.html>)

Author: Mike Ash

Published: 2017-09-23T00:57:00Z

Content type: article

Language: en

Sources: [Mike Ash](<https://devfeed.tech/sources/mike-ash.md>)

Topics: [Swift](<https://devfeed.tech/topics/swift.md>), [implementation](<https://devfeed.tech/topics/implementation.md>)

Tags: [article](<https://devfeed.tech/tags/article.md>), [change](<https://devfeed.tech/tags/change.md>), [implementation](<https://devfeed.tech/tags/implementation.md>), [swift](<https://devfeed.tech/tags/swift.md>)

## AI overview

An explanation of how weak references are implemented in Swift 4, comparing the current implementation with the older design and discussing changes made to address memory usage and concurrent-read safety.

## Source excerpt

Soon after Swift was initially open sourced, I wrote an article about how weak references are implemented. Time moves on and things change, and the implementation is different from what it once was. Today I'm going to talk about the current implementation and how it works compared to the old one, a topic suggested by Guillaume Lessard. (Read More)