I suspect that if your process uses an asynchronous continuation, your start process call will return when the asyc continuation is reached. In this case, the ended flag should be false. You could consider a user task as implicit async continuation, but you can also declare a task as an explicit async continuation.
Ive considered your requirement. If your use case is you want to implement a function as a process;
Ensure there are no async continuations.
On process completion, store the process variable as thread local variable.
Use a wrapper component to call the start process, when control returns, extract the thread locals and re-package as a function call response…
regards
Rob