Has anyone had any success detecting if their KMP code is running on an iOS simulator? `targetEnviro...

# multiplatform

[Jonathan]

Has anyone had any success detecting if their KMP code is running on an iOS simulator? targetEnvironment(simulator) isn’t callable from KMP.

[François]

In swift you check on runtime :
-> ProcessInfo.processInfo.environnment[“XCODE_RUNNING_FOR_PREVIEW”] != nil

[Jonathan]

Have you tested on a simulator? I figured this would only work for the SwiftUI previews.

[François]

Oh, the simulator, my bad

[Jonathan]

Also, I’m writing a library and I would like functionality internal to the library to determine if running in simulator so I can’t use pure Swift otherwise I’d use the targetEnvironment(...).

[François]

So yeah, It’s swift compiler directive

[François]

I guess, you can create a swift/objc/kotlin bridge to check this condition

[Jonathan]

Wouldn’t that require the consuming app to pass into some Swift object into my library?

[François]

but directive is only during the compilation not runtome

[François]

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[Jonathan]

Not sure how this library would work. Seems like the only way to determine if running on a simulator is to use a compile time flag since the builds for a simulator and real iPhone are different.

[Jonathan]

Do you have a basic example to achieve it with your library?

[François]

@objcMembers public class MySwiftBridge: NSObject {
    static public func isBuildForSimulator() -> Bool {
        #if targetEnvironment(simulator)
          return true
        #else
          return false
        #endif
    }
}

[François]

Or in kmp, you can use subtarget (iosArm64Main & iosSimulatorArm64Main)

[François]

with expect/actual

[François]

I guess, the last one is better

[Jonathan]

Why do you say the last is better?

[François]

you don’t need to use a plugin; the kotlin compiler will do the job the expect/actual

[Jonathan]

The latter option has the drawback of effectively having “empty” sourceSets which just return true

[François]

you have what you need easily in that way

[Jonathan]

I agree using the default KMP toolset is easy but my concern is my library would be “bloated” with ugly marker source sets 🤣… I will look review your library/plugin and investigate what methods works better for me.

[Jonathan]

Thanks for the help

[Jonathan]

Declaring separate source sets for iOS simulators is very laborious because all my expect declarations will need actual implementations. It would be very nice if I could just override certain behavior.

[François]

Or, you can just create a small kotlin module with what you need.