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kotlinlang

Hi there!, I’m using a code that uses Metal or OpenGL depending on if this runs on iphone or iphonesimulator. What’s the KMM approach to do this kind of `ifdef` ?

You can use expect/actual as usual and use the iosX64 (simulator) and iosArm64 (device) targets with corresponding source sets to provide different implementations for each platform.

:thumbsup: understood, it is a bit painful since it is just one line of code which is different

but probably I can leverage this for other changes

Yes, the way we do it is have expect/actual for a method called ifSimulator and ifDevice that take a callback. Basically we re-implement the ifdef functionality using expect/actual. You could also just have a platform dependent constant and use if (isSimulator) for example.

mmm, I asume that ifSimulator is not exported so I cannot use directly?

I’m trying this approach, but actually I don’t know how to have different source sets for iosX64 and iosArm64 in the gradle file. Is it documented somewhere?

This is what I have in my project:
```kotlin {
  iosArm64() {
      binaries {
          framework() {
              embedBitcode("bitcode")
          }
      }
  }

  iosX64() {
      binaries {
          framework() {
              embedBitcode("bitcode")
          }
      }
  }

  sourceSets {
      iosMain {
            dependsOn(commonMain)
            iosX64Main.dependsOn(it)
            iosArm64Main.dependsOn(it)
      }

      // These two should be implicit, just in case
      iosX64Main {}
      iosArm64Main {}
   }
}```


thanks!, it looks like it is working now. However if I remove this from gradle
```    val iosTarget: (String, KotlinNativeTarget.() -&gt; Unit) -&gt; KotlinNativeTarget =
        if (System.getenv("SDK_NAME")?.startsWith("iphoneos") == true)
            ::iosArm64
        else
            ::iosX64

    iosTarget("ios") {}```
I get a lot of errors in the Android studio ide

I cannot keep it or it will complain about duplicate targets

Yes, sometimes AS gets confused by multiple iOS targets. We use this workaround:
```boolean isIdeaSyncing = System.getProperty('idea.sync.active') != null

kotlin {
    if (isIdeaSyncing) {
        iosX64("ios") {
        }
    } else {

        iosArm64() {
        }

        iosX64() {
        }
    }
...
}```


just a side note, if somebody else reads this thread. I’m placing the `expect` function in `iosMain` and `actual` implementations in `iosX64Main` and `iosArm64Main` folders. (don’t forget to put everything in the same package!)

I tried putting the `expect` in `commonMain` but that does not work

yes, then you would also need to implement it for example on Android, iosMain is definitely the right place to put it