During a conversation at work, it became apparent just how disconnected modern software development is from the underlying hardware, or even from the Operating Systems the application processes run on. Coincidentally, I was getting ready to finish up my first SwiftUI introductory book. I decided to push the release of that book a bit farther, and capture the information I wanted to convey in that conversation, in a better articulated manner and through the lens of Apple’s systems.

In this short for post, we are going to explore the basic mechanisms by which you can create a very basic application, which keeps running until you close it. The idea is to explore how a rudimentary loop can be used to control the lifecycle of an application. This technique is foundational to almost every application you would run and build, from iOS apps to browsers to video games.