sorry about a possibly stupid question but is this: `val x = (async { foo() }).await()` ever differe...

# coroutines

[Olli Helenius]

sorry about a possibly stupid question but is this: val x = (async { foo() }).await() ever different from just val x = foo()?

[ephemient]

var i = 0
launch { i++ }
val x = i

var j = 0
launch { j++ }
val y = async { j }.await()

x == 0 && y == 1 (not guaranteed, but likely in a single threaded dispatcher)

[Olli Helenius]

so does that mean the async call is a suspension point?

[uli]

await is

[Olli Helenius]

ah indeed

[Olli Helenius]

but if foo() in my example is a suspend fun does it make any difference in that case?

[uli]

yes, even in a single threaded dispatcher you can have state changed by other coroutines at each suspension point

[Olli Helenius]

i mean does wrapping the call in async make any difference? the call to foo() is also a suspension point right?

[uli]

depends on foo. If foo suspends it is. if foo does not suspend it’s not. Calling this foo will not suspend:
suspend fun foo(): Int { return 1 }

[wasyl]

iiuc it’s a possible suspension point, it’ll not suspend unless you suspend inside foo

[Olli Helenius]

i see, thanks