Win API to determine if webcam is in use by other apps

In Skype, if the webcam开发者_StackOverflow中文版 is in use, it shows a relevant message. Is this possible using Win API?

I know absolutely nothing about the imaging API, but I suppose that you may simply try to open the webcam and check the error code: probably there's an error code that means "device already open". If you get that code you can display a relevant error message.