I have a question about controlling a mouse pointer in Linux (i.e. in Webbrowser) by C++ Code in Eclipse. So my question is which libraries do I need for this? I found some code in the Internet but only for Windows.
There is no standard or platform-independent way, you need to look up how to do it for your operating system. Be aware that getting and/or setting the actual absolute position of the mouse cursor is something that antivirus software hate.
In *nix, the way you accomplish this depends entirely on the windowing system being used. There might not even be a windowing system though.