Detecting premature end of spawned threads with std.concurrency

[Steven Schveighoffer via Digitalmars-d-learn]

On 9/3/15 5:20 PM, Matt Kline wrote:
> TDPL suggests that calls to std.concurrency.send will fail with an
> "OwnedTerminated" or "OwnedFailed" exception if the destination thread
> has exited, but neither the docs nor the current Phobos implementation
> make any mention of such exceptions. Thinking the information was just
> outdated, I searched the Git history of Phobos for such types, but found
> nothing.
>
> What are current best practices for determining if a child thread has
> died? And should these types be added to TDPL errata?

It seems this is not handled.

Looking here:

https://github.com/D-Programming-Language/phobos/blob/master/std/concurrency.d#L506

spawn creates the thread, then calls the function, but never sets a flag 
indicating when the thread is done. This could be added quite easily by 
adding a scope(exit) to the executed function (exec). It would not 
happen if the thread is terminated abnormally, but any thrown exception 
should trigger the flag. I'll note that the MessageBox class has a 
close() method that seems like it could be called.

Anyone want to make a PR? And no, I'm not going to :)

-Steve