How to write an unkillable process for Windows?

Question

I\'m looking for a way to write an application. I use Visual C++ 6.0.

I need to prevent the user from closing this process via task manager.

Answer 1

That all depends on who shouldn't be able to kill that process. You usually have one interactively logged-on user. Running the process in that context will alow the user to kill it. It is her process so she can kill it, no surprise here.

If your user has limited privileges you can always start the process as another user. A user can't kill a process belonging to another user (except for the administrator), no surprise here as well.

You can also try to get your process running with Local System privileges where, I think not even an administrator could kill it (even though he could gain permission to do so, iirc).

In general, though, it's a terribly bad idea. Your process does not own the machine, the user does. The only unkillable process on a computer I know is the operating system and rightly so. You have to make sure that you can't hog resources (which can't be released because you're unkillable) and other malicious side-effects. Usually stuff like this isn't the domain of normal applications and they should stay away from that for a reason.