Yep, I’m aware of that too, doesn’t change my initial point

…right…tell that to cmd.exe or the OpenVPN daemon, or the soft ether VPN daemon, or OpenConsole.exe, or Idk, I only tested 4 that immediately came to mind but my point stands. There are a lot of programs that do not have a window handle and do not bother with window messages.

You clearly didn’t read my message…I said a “window close message.” I.e…WM_CLOSE. that is not a process signal, it’s a window management signal. Hence taskkill not working without /f on headless processes

TIL about the console signaling stuff, good to know. I am aware of SEH but that seemed a little too in the weeds for this discussion since that’s as you say akin to SIGSEGV

Ironically it’s actually the opposite. Linux has signals, and with the exception of SIGKILL and I think SIGABRT they can all be handled gracefully. Windows on the other hand doesn’t have signals, it can only TerminateProcess() which is forceful. The illusion of graceful termination on windows is done by sending a Window close message to all of the windows belonging to a given process, however in the event the process has no windows, only forceful termination is available due to the lack of a real mechanism to gracefully terminate processes. That’s why the taskkill command tells you a process requires forceful termination when you run it against something headless.