Hi! I need to run two `Job`s simultaneously, how w...

# coroutines

[Gabriel Feo]

Hi! I need to run two `Job`s simultaneously, how would I do this with coroutines? I understand how to do this when I need return values with Deferred and awaitAll, but I don't know how I should do this with simple `Job`s

[Luis Munoz]

job1 = launch { code block.. }
job2 = launch { codeblock..}

[octylFractal]

if you need to wait for them use join, not sure if there's joinAll

[serebit]

listOf(launch { }, launch { }).joinAll()

[Gabriel Feo]

@Luis Munoz, @octylFractal
So I read a bit about join. I understand that when launching two `Job`s as above,
• if I don't join each to the parent coroutine, they will run independently, but the parent only finishes when both children do
• if I do join each to the parent coroutine, they will run sequentially, job2 runs only after job1 finishes, and still the parent finishes only when both children do

[Gabriel Feo]

Is that right?

[octylFractal]

no, that's wrong, they run independently regardless of join call

[octylFractal]

launch starts the coroutine, unless you add CoroutineStart.LAZY

[Luis Munoz]

join suspends so that it doesn't go to next code statement until that job completes

[Gabriel Feo]

I see. Thanks everyone. So to separate the concepts I was mixing up here:
1. just calling both in sequence would run them synchronously callSuspendFun1(); callSuspendFun2()
2. launching them separately would make them run simultaneously but with the "parent" coroutine continuing execution independently of the jobs completing
3. using join on each launch separately would make them run sequentially like case 1
4. using joinAll on the two launches would launch them simultaneously, with the "parent" only resuming execution once the two jobs have completed

I think I got it now, but I should go over the basics...

[tseisel]

5. Wrap your 2 launch inside a coroutineScope block, and execution will resume after both jobs have completed just like 4 (but without having to join).
This is better for structured concurrency.