```fun main() = runBlocking { // this: CoroutineSc...

# coroutines

[JP]

fun main() = runBlocking { // this: CoroutineScope

    coroutineScope { // Creates a coroutine scope
        println(this)
        println(this@runBlocking)
...

and the printed result is:

"coroutine#1":ScopeCoroutine{Active}@64a294a6
"coroutine#1":BlockingCoroutine{Active}@7e0b37bc

Why do they have the same name “coroutine#1”?
If they are different coroutines, shouldn’t they have different labels?
Am I missing something?

[Francisco Javier Ruiz Rodriguez]

I think coroutine#1 is the parent of both, in this case, thew runBlocking

Try this, and you will see the difference:

import kotlinx.coroutines.*

fun main() = runBlocking { // this: CoroutineScope
    coroutineScope { // Creates a coroutine scope
        println(this)
        println(this@runBlocking)
        test()
    }
}

fun test() = runBlocking {
    println(this)
}

[elizarov]

coroutineScope { ... } does not create a new coroutine, even though it has its own Job instance, and thus also uses the same id.

[JP]

I see, I just vaguely thought after simply skimming through the coroutineScope function

public suspend fun <R> coroutineScope(block: suspend CoroutineScope.() -> R): R =
    suspendCoroutineUninterceptedOrReturn { uCont ->
        val coroutine = ScopeCoroutine(uCont.context, uCont)
        coroutine.startUndispatchedOrReturn(coroutine, block)
    }

that it would create a new coroutine. Then I guess here val coroutine = ScopeCoroutine(uCont.context, uCont) does not return a new coroutine.

[elizarov]

The trick is how you define a "coroutine". Here we use a narrower definition, where a "coroutines" is something that works concurrently with the rest of your code. Since coroutineScope { ... } (unline launch) is not concurrent with the surrounding code we don't call it a "coroutine builder" and we don't consider it to actually create a new coroutine.