<@UFL90KYE5> - I just shifted my lauch3 just above...

# announcements

[Guru]

@Antanas A. - I just shifted my lauch3 just above coroutineScope{...} and it works just fine. But, surprisingly any thing below coroutineScope{...} is never gonna execute...!! It is blocking..! May be its a bug. I have no idea.!

[gildor]

People, could you please use threads, it's hard to follow discussion of other messages

[Antanas A.]

yes of course coroutineScope call is blocking (it is suspending your execution)

[Antanas A.]

and blocks(suspends) until all children coroutines will be completed

[Antanas A.]

so in your example you are launching new coroutine inside coroutineScope, and delaying 2seconds, then 2seconds, then MAX_VALUE

[Antanas A.]

so that coroutine will never be completed

[Antanas A.]

so your coroutineScope also never completes, because of parent-child relationships

[Antanas A.]

so coroutineScope call will be blocked (suspended) and no execution would happen below that code

[Antanas A.]

it's not related to runBlocking or anything

[Guru]

It would have made sense if runBlocking would have had not returned to main() as coroutineScope{...} continue execution. But, it's blocking even a expression below that.

[Guru]

isn't it a thread blocking?

[Antanas A.]

could you explain what do you want to say?

[Antanas A.]

you call "coroutineScope" will suspend execution until everything inside coroutineScope completes

[Antanas A.]

thats why you do not get anything executed after coroutineScope

[Guru]

yes you are correct. but according to http://kotlinlang.org coroutineScope{...} will not block the current thread while waiting for all children to complete.

[Antanas A.]

no, there are no any thread blocking

[Antanas A.]

could you give me an URL to exact doc?

[Antanas A.]

maybe you've misinterpreted something (or there are bug in docs)

[Guru]

http://kotlinlang.org/docs/reference/coroutines/basics.html

[Guru]

go to Scope Builder section

[Antanas A.]

" It creates new coroutine scope and does not complete until all launched children complete. "

[Antanas A.]

it says what I've said

[Antanas A.]

but

[Antanas A.]

"The main difference between runBlocking and coroutineScope is that the latter does not block the current thread while waiting for all children to complete."
Here I think where you've got confused

[Guru]

yes

[Guru]

please correct me

[tseisel]

coroutineScope is NOT blocking. It suspends as long as it has non-completed children coroutines, which is the case because it has a children coroutine (launch2) that delays for a very very long time.
Note that runBlocking has nothing to do with that ; even without runBlocking, launch3 would have to wait until children of coroutineScope have completed before resuming execution and reaching launch3.

[Antanas A.]

to understand

[Antanas A.]

runBlocking is function, and coroutineScope is suspend function


if you'll call runBlocking anywhere inside code it will BLOCK current thread

[Antanas A.]

if you'll run coroutineScope {} it will SUSPEND execution

[Antanas A.]

but not a thread

[Guru]

ok. thank you very much. got it 🙂

[Antanas A.]

the result feels the same, but mechanics is different

[Antanas A.]

so I think you've observed that execution has stuck

[Antanas A.]

And thought that thread has been blocked

[Antanas A.]

hope it helps you to understand

[Guru]

exactly yea... thanks it is helpful to debug further.

[Guru]

Thanks buddy. All I did now is to put launch{1}, launch{3} inside coroutineScoope{..} and it is resuming its work now. 🙂

[Antanas A.]

actually you don't need that coroutineScope at all, runBlocking itself will wait until all launches inside runBlocking will complete