# Cross-platform API to determine OS version and name in Swift

In this blog post, I'll introduce a new lightweight Swift Package that helps developers easily determine the operating systems `name` and `version` in Swift for reporting purposes.

## Motivation

I think it is challenging to print out the operating systems `name` and `version` on which a Swift app might run if you are in need to support various platforms.

Older APIs, like `UIDevice.current.systemName` , may still be useful but are not universal as `UIKit` cannot be used on all operating systems. Especially when we consider that Swift also runs on non-Apple platforms like Linux or Windows.

Different APIs may have been introduced, e.g. `WKInterfaceDevice.current().systemName` on WatchOS.

Sometimes the API behaves quirky for different environments. I am talking about Mac Catalyst. Originally this meant to make a Mac version of your iPad app. Nowadays, it is possible to run unmodified iOS apps on a Mac (Apple Silicon!).

Then `UIDevice.current.systemName` will return "iPadOS as a value while some might have expected or hoped for a different value ("macOS").

Similar challenges await us when determining the version despite that there is a powerful, low-level Foundation API `ProcessInfo.processInfo.operatingSystemVersion` that can be used across platforms.

Still, there is a discrepancy between `operatingSystemVersion` (a formal struct including major, minor and patch build version numbers) and `operatingSystemVersionString` (a localized string) when it comes to the Mac Catalyst environment.

## Solution: `OSInfo` Swift Package

That's why I introduced `OSInfo` Swift Package. A universal, cross-platform API that can deal with modern platforms and environments.

```swift
import OSInfo

// Example for running as Mac Catalyst (or unmodified iOS app) on Mac
print(OS.current.name) // "macOS"
print(OS.current.version.description) // "13.0.1"
print(OS.current.displayVersion) // "Version 13.0.1 (Build 22A400)"
print(OS.appleFamily) // true
// -- alternative
print(OS(underlyingMacOS: false).name) // "iPadOS"
print(OS(underlyingMacOS: false).version.description) // "16.1"
```

The Swift Package is well documented, and if you still have questions, please get in touch with me.

You can find the Swift Package on GitHub.

%[https://github.com/MarcoEidinger/OSInfo] 

And also on Swift Package Index.

%[https://swiftpackageindex.com/MarcoEidinger/OSInfo] 

## Apple Vision

A new operating system **visionOS** internally called xrOS) was revealed at Apple's Word Wide Developer Conference 2023. It will run on the upcoming mixed reality headset Apple Vision Pro that will be shipped in 2024.

With Xcode 15 Beta 2, you can build apps for Apple Vision Pro that either

* run natively using RealityKit and SwiftUI by leveraging the visionOS SDK
    
* run your app designed for iPad by leveraging the iOS SDK
    

My Swift Package `OSInfo` already provides you appropriate values.

```swift
 import OSInfo

// Example for running natively on Apple Vision (SDK "visionOS")
print(OS.current.name) // "visionOS"
print(OS.current.version.description) // "1.0"
print(OS.current.displayVersion) // "Version 1.0 (Build 21N5165g)"
print(OS.appleFamily) // true
```

Here is the output when running on Apple Vision (Designed with iPad)

```swift
 import OSInfo

// Example for running on Apple Vision (Designed with iPad) with SDK "iOS"
print(OS.current.name) // "iPadOS"
print(OS.current.version.description) // "1.0"
print(OS.current.displayVersion) // "Version 1.0 (Build 21N5165g)"
print(OS.appleFamily) // true
// -- alternative
print(OS(underlyingMacOS: false).name) // "iPadOS"
print(OS(underlyingMacOS: false).version.description) // "17.0"
```

In a future version of `OSInfo` I hope I can improve the output (e.g. also return "visionOS" for `OS.current.name`) as soon as Apple provides better underlying APIs.