is it possible, in C++, to get the current RAM and CPU usage? Is there a platform-indepentent function call?
Sadly these things rely heavily on the underlying OS, so there are no platform-independent calls. (Maybe there are some wrapper frameworks, but I don't know of any.)
On Linux you could have a look at the getrusage() function call, on Windows you can use GetProcessMemoryInfo() for RAM Usage. Have also a look at the other functions in the Process Status API of Windows.