A friendly reminder: <https://stackoverflow.com/qu...

# coroutines

[elizarov]

A friendly reminder: https://stackoverflow.com/questions/46226518/what-is-the-difference-between-launch-join-and-async-await-in-kotlin-coroutines

[evan]

Would you say launch is a CoroutineBuilder designed to work similar to a threads behavior on Java? They are “fire and forget”, and swallow errors with the caveat that child `Job`s cancel parents with a Throwable.
While async is a CoroutineBuilder designed to work like C#’s async/await, and expects a value returned, even if its an error similar to java futures with Deferred

[elizarov]

Yes.

[evan]

If launch and async are considered essential “base” builders, is there a performance overhead to implement CompletableFuture, or other frameworks wrapped in the suspendedCoroutine builder? I understand the benefit of converting a blocking callback to a suspending callback, but I don’t realize the cost compared to launch and async, builders which seem to only denote a preference in error return.

[elizarov]

They are not base builders. Base builder is startCoroutine from stdlib. All other builders are implemented on top of it: launch, async, futures, etc are all equally high-level builders. Their impls even follow the same pattern.