I know how put content to and retrieve content from the clipboard.
However, between these two operations, it is possible for another operation to change the content
Here is a write-up that I did a few years ago, detailing clipboard even monitoring via the Windows API: http://www.clipboardextender.com/developing-clipboard-aware-programs-for-windows/6 Please pay particular attention to the "common mistakes" section. Hardly anyone does this correctly the first time.