What WndProc Windows Message for this

I think you need to reveal more about what your goal is. That is, in my app I didn't see any new messages when I had CDBURNERXP make a CD or DVD. So messages appear to only be in each app's message system.

If such messages were system wide in Windows, I fear this OS would be even less secure than it is.

So you mean it is not possible to get notification when another app is performing this action?

But I think there should be a way of knowing. I'm not sure but I think there is no event that can happen on a computer which doesn't have an OS message map, but as I've said I'm not sure but according to what I once saw especially with Windows OS is that its a Message driven OS, which means most of the events are derived by Messages or trigged by message that the OS broadcast to app the registered apps to recieve that type of message.

In C++ I think in order to receive these messages you need to register your app for SYSTEM_EVENTS | USER_EVENTS | SERVICE_EVENTS | EXECUTE_EVENTS

I think you need to try what you wrote in your last message about registering and see what you get. Here I did not do that step (no reason to) and did not see any messages outside of what my app would generate.

I did ask what your goal was but didn't get a good answer. Sometimes folk want to lock down the PC to stop use of USB sticks, control file copies and so on. That's an arms race that is summed up the in the movie WarGames.

So why not try your idea but what happens when I use CDBURNERXP, FreeBurn or other apps you didn't expect? I'm guessing what your goals are.

My goal is to get notification when these request accures. I want to also get its parameters data which will have the data that is to be written to the disc, the data location. I need to work with the data before it is written to the disc so what I want to do is to get notifications when there is a software attempting to burn a disc.

That's a partial answer to my questions. No one I know has tried to tinker with the data in such a way. For decades I prepare what I want to burn before I click burn (or record, copy.)

Good luck in your endeavor but I worry that your app would be too specific to the burning app and would not work if I went with ISOBurn, FreeBurn, CDBURNERXP or other apps. Besides the issue that CD/DVD/BR recording is in steep decline. Folk here copy stuff to USB sticks 99 out of 100 times.

This can really rankly folk that are fine tuning the buggy whip production lines.

You must develope and install a driver. Search for MS' DDK, driver deveopment kit.