Running a cleanup after a program crashes

I'm currently writing quite a simple app, but it makes a change to the OS which gets changed back when the program is closed.

The worry of course, is if th开发者_JS百科e program crashes. I can do everything in my power to prevent it from crashing, or handling things if it does crash - but I can't stop someone from force closing the process (unless I can?)

Is there a way to catch that event and run just a very quick cleanup before the process exits?

I don't think there is anything you can do if your process gets killed - one approach would be to have your app spawn a helper process that is just there for this case. When your app terminates that process can detect that and "fix" the OS setting as desired before it shuts down itself - obviously this only would work if that other process doesn't get killed first.

You can hook UnhandledException. You can't stop the application terminating, but you can log or do some clean up. This allows you to handle the case of application crashes.

It terms of someone actually just killing the process there's nothing you can do about that.

Program defensively.

Write the original settings to a file. Delete the file when closing. When starting, check whether the file is there - if it is, your process was killed and you know what to return the settings to.

Programming 201 - the basics of transactions, applied to system settings wit hthe program runtime as transaction boundary.

If you don't mind a little interop to C or C++ code, and if you're running on Windows Vista or newer, you could make use of the Application Recovery and Restart APIs. These APIs tell Windows to intercept your process when something catastrophic happens, so that you can perhaps call a little cleanup code before Windows kills the process completely.

See http://msdn.microsoft.com/en-us/library/cc948909.aspx.