How to track changes in overall volume on Windows?

Question

Windows

I wanted to find how to do it through WinAPI, the matter dragged on.
So I'm asking you for tips.

Answer 1

write your own dll with a couple of exported stdcall functions. (yes, dll will have to be carried with you). for writing, you can
start from something like this: https://github.com/BarryReid/volumeLevels/blob/mas
...
changes, but in extreme cases - in a cycle to get the level and check for changes.