Console Application cannot stop properly a thread

[wysota]

Indeed, there is a solution for Unix signals. By contrast, Windows spawns a thread to execute the handler everytime the signal is received; sadly, handler unregistration offers no way to synchronize with any thread currently executing the handler being unregistered.

It is enough to check in the handier whether the application object is valid before proceeding. However I am quite surprised about what you say that an extra thread is spawned - by whom? Operating system does not spawn threads for processes. The code for this would have to be generated by the compiler. I just read the docs for this function and it says nothing about any extra threads being spawned. Where did you get this information from?