A modern programming language that makes developers happier.

kotlinlang

Not really. There is no generic way to know if the current thread already has event loop unless you are programming in some kind of a framework that guarantees that any thread has an event loop. Why do you care about threads anyway?

Maybe just put event loop to ThreadLocal,  so you can check is event loop there or not

Looper from Android does this
<https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/os/Looper.java#93>