I have a function declared as (in KMM) : ```fun get(): Any?``` In my iOS implementation I have: `*fu...

# multiplatform

[Pavel Lahoda]

I have a function declared as (in KMM) :

fun get(): Any?

In my iOS implementation I have:
*func* get() -> *Any*? {
*return* Int(0)
}
Which I call from KMM as:

val myValue = myImplementation.get() as Int

and I am getting the following Exception:
kotlin.ClassCastException: class kotlin.Long cannot be cast to class <http://kotlin.Int|kotlin.Int>

Not sure why this might happen. Any comments/ideas are welcome. Thanks

[Tijl]

Int is 64 bit when compiling for a 64 bit target in Swift, so it maps to Long in Kotlin

[Casey Brooks]

You shouldn’t cast primitives in Kotlin. Use the extension functions instead (.toInt(), .toLong(), .toDouble(), etc)

[Pavel Lahoda]

@Tijl Thanks for info. Do you know if this is documented somewhere?

[Pavel Lahoda]

@Casey Brooks OK, but my interface returns Any as the type is not known at this point. I can't really use toInt() as this is not available on Any. Casting to Int is my only option.

[Casey Brooks]

https://kotlinlang.org/docs/numbers.html#explicit-number-conversions

[Casey Brooks]

I think I read the original question a bit too quickly. It looks like this is a situation of the platform Number representations not playing well with Kotlin. I’m not too familiar with Swift/obj-c, but it is documented that Swift/obj-c primitives generally don’t have enough info to the Kotlin runtime to really handle them very well https://kotlinlang.org/docs/native-objc-interop.html#nsnumber

So in this case you’d probably have to cast to Long, and then use .toInt() on that result. (myImplementation.get() as Long).toInt()

[Pavel Lahoda]

I was looking for documentation on Kotlin Multiplatform mapping Int to Long on 64-bit system (on Android this work as expected). I understand that casting it first to a Long is a workaround for me. Thanks