Are there any plans to support `runInterruptable` ...

# coroutines

[kevin.cianfarini]

Are there any plans to support runInterruptable in Kotlin/Native (posix)? Are there technical limitation to this? I think we could do this with signals.

[kevin.cianfarini]

My use case is that I have a blocking call on native which waits for the kernel to do something. It is not a syscall. Because runInterruptable does not support native, I'm having to use a blocking call that times, and then spin needlessly with an arbitrary timeout.

For reference, this is all in the context of binding kotlin native to io_uring. I would like to be able to do the following:

val dispatcher = newSingleThreadedContext(...)
runInterruptable(context = dispatcher) {
  while (true) {
    io_uring_wait_cqe(...) // blocks until kernel gives us a value. 
  }
}

Instead I am having to do this:

val dispatcher = newSingleThreadedContext(...)
val timeout = /* 100 milliseconds */
withContext(dispatcher) {
  while (isActive) {
    io_uring_wait_cqe_timeout(..., timeout) // blocks for 100ms or until kernel gives us a value.
  }
}

[kevin.cianfarini]

Originally I was doing the following:

withContext(newSingleThreadeContext(...)) {
  while (isActive) {
    io_uring_wait_cqe(...)
  }
}

But there's a subtle bug here. If the parent coroutine scope is cancelled, and there's no new value is ever returned from io_uring_wait_cqe, then cancelling the scope has no effect. This loop never checks the isActive condition and it hangs forever.

[kevin.cianfarini]

I filed an issue because I didn't see anything like this on the issue tracker. https://github.com/Kotlin/kotlinx.coroutines/issues/3563

[Dmitry Khalanskiy [JB]]

Replied under the issue.