Nico:
For the 8052 end of the serial link there are quite a few helpful aids right here on this web site. If you go to This Forum Post you can see links where you can download UART operating code for an 8052 type processor. This may require slight modification to suit it to your processor derivative.

For the PC end I have to make a quick assumption that you are working in Windows since you are using C++. I could direct your attention to a very fine C++ class for serial communications called SerialCom.cpp: implementation of the CSerialCom class written by Shibu K.V (shibukv@erdcitvm.org). I have used this C++ class in a project that I did to connect an outboard controller to a Microsoft VC++ 6.0 Windows program. You can read about this class and download the free source code and demo project from TheCodeProject web site at Topic Page: CSerialCom - A simple Class Implementing Serial Communication in Win-9X/2000.

I hope this gets you on your way to a connection.
Michael Karas