There are different ways of launching a coroutine in Kotlin. I found a couple of examples where GlobalScope
and CoroutineScope
are used. But the latter one is being created directly when launching a coroutine:
Using GlobalScope
:
fun loadConfiguration() {
GlobalScope.launch(Dispatchers.Main) {
val config = fetchConfigFromServer() // network request
updateConfiguration(config)
}
}
Using CoroutineScope
instances, created directly when launching a coroutine:
fun loadConfiguration() {
CoroutineScope(Dispatchers.Main).launch {
val config = fetchConfigFromServer() // network request
updateConfiguration(config)
}
}
In this case is there a difference between these two approaches?
Doesn't the second case violate the principle of structured concurrency?
Doesn't the second case violate the principle of structured concurrency?
Actually both cases violate it equally, because they have pretty much the exact same semantics. All the warnings against using GlobalScope.launch
that you may have encountered, apply to CoroutineScope().launch
just the same. A slight difference is that the latter is entirely pointless, whereas the former at least has some legitimate use cases.
Writing CoroutineScope().launch
instead of GlobalScope.launch
obscures the intent and consequences, as well as creates a needless object every time.
I think the CoroutineScope().launch
idiom came into being solely because it circumvented the warnings you get for GlobalScope.launch
.