Hi everyone, does anybody had a problem with delay() on ios platform? I have a simple loop: while(true) { println(“log1”) delay(1000) println(“log2") } launched on GlobalScope. On Android it works fine but on ios it doesn’t. Like delay has infinite timeout…

You mean that delay never returns?

Yes. No “log2” printed on iOS.

I’ve seen some never ending tests on iOS. I filed a bug for it here. Perhaps the problem is the

delay

statements. Can you comment issue, thumbs it up and state that you are seeing this problem? https://youtrack.jetbrains.com/issue/KT-37958

@Olenyov Kirill Which kotlinx.coroutines version are you using exactly?

1.3.4

Does it*

Yeah, right😅

(you can edit messages FYI) Are you using 1.3.4 (no native-mt) with Kotlin 1.3.61 on iOS? When you try, the app is in foreground? Is the app crashing (which triggers the debugger adn freezes the app) or are any UI elements still responding?

1.3.4(no native-mt) with Kotlin 1.3.70 App is in foreground, no crash and no any UI problems. Just tried 1.3.5 - the same.

delay requires an event loop. you should see an error about this in your stdout.

Thanks. Unfortunately I don’t see any error about delay:(. Which error? Where can I read about it? So, I can’t use delay() on ios? What should I do in this case? I just need to have “periodic updates” inside common code..

try wrapping it with

runBlocking

Hmm, but we don’t have runBlocking() in kotlinx-coroutines-core-common..

@Olenyov Kirill Oh, I recall. On Kotlin/Native, unless you use the

native-mt

artifacts, there's no

Dispatchers.Default

available, so the coroutine launch is never dispatched. Only

runBlocking

is available on Kotlin/Native even without the native-mt artifacts (from native code, not from common code).

So the only choice is moving to native-mt to have delay() in common part for both platforms, right?

@Olenyov Kirill Or creating your own event loop running on a single thread. If you search for iOS coroutines main thread dispatcher, you'll find an issue where a comment gives an implementation that handles delays and cancellation.

Ok. Got it. Thank you!

it would probably be better to get the current queue and then resume on that queue

Hm, I thought that current queue is the same as main queue without “native-mt”. Is it wrong?

@Olenyov Kirill You should not need a custom delay implementation. Instead, just have a dispatcher that supports delay, like

Dispatchers.Main

and

Dispatchers.Default

in

native-mt

, or this dispatcher: https://github.com/Kotlin/kotlinx.coroutines/issues/470#issuecomment-440080970 (issue is first link by Googling "ios main thread coroutines dispatcher", you then need to scroll to find the snippet I linked, you can see a great number of positive reactions to it)

Hi, thanks. Just tried this solution but it seems something is going wrong. In xcode I get a lot of random errors like SIGABRT or EXC_BAD_ACCESS in random places. May be it’s related with “cancelation” of Jobs..? Or maybe because the solution is quite old(1.5 years..) But with the simple solution(my customDelay) no errors…

I'd try with latest native-mt and Kotlin version