I want an exception message but my threaded callback just dies or crashes

[Markus]

I have cleaned it up, kind of. Just in case you want to compile 
it. The Zip contains some DLL from 
https://github.com/spatialaudio/portaudio-binaries where you can 
find the original if you want.

https://gofile.io/?c=NpUxrJ

I'm in general thinking of buying a Mac. I know it has not much 
to do with this, but debugging Swift code in Xcode must be so 
"gorgeous" as they say.