[RESOLVED] DeleteObject API for gdi32

I am using a gdi32 api. Specifically CreateRoundRectRgn.

I have learned that you should clean up after you use it. The way is to use DeleteObject.

I would like to know.
What happens if you do not cleanup? What are the symptoms? Is it just proper programming? Or, does something happen to the system? It seems I can close a program without executing the DeleteObject API.

When I use it, how do I know it worked properly?

Thanks