I have an app that running in Catalyst and also on iOS.

I want certain features not to be available on MacOS (Catalyst), but I can't seem to identify when the app is running on a Mac. The following code reports the OS as iOS when running on the Mac.

#if os(iOS)
print("OS is iOS")
#elseif os(macOS)
print("OS is MacOS")
#elseif os(watchOS)
print("OS is watchOS")
#elseif os(tvOS)
print("OS is tvOS")
#endif

To some degree I can understand why this is happening, but all said, the reported OS should be MacOS.

Does anyone have an idea as to how I can determine when the app is running on a Mac?

BTW, kinda related but when I use Testflight to distrubute the app, the email invite only mentions iOS (it says something like "Install Testflight for iOS") but clicking the links on a Mac allows you to install Testflight on Mac too. The email is misleading and does not make for a great UX for the beta tester who wants to test the app on a Mac.

Any advice here folks?

Thanks very much!

ProcessInfo can tell you if it is a Catalyst app, it can also get the display version or numeric version of the operating system.

https://developer.apple.com/documentation/foundation/processinfo/3362531-ismaccatalystapp

I'm fairly new to Swift and SwiftUI, but those look like compiler conditionals, which means they get backed in when you build. I believe that you use something like below for runtime conditionals.

if #available( macOS 11.0, * ) { }

Edit 2: To include this potential sample.

if ProcessInfo.processInfo.isMacCatalystApp || ProcessInfo.processInfo.isiOSAppOnMac {}