data pass (freepascal-dll vs mt4)

hi, I need a sample code, where mt4 is sending rates data to the dll and then dll is giving back this data to mt4. (no need to make anything with this data, I only need to see how the "rates-communication" works between them)
I found this, but 1/ it is quite old, doesnt work (before 600+ build) and 2/ Id like to see the example by using MqlRates
anybody can help me?

An imported DLL can access the same process' space; meaning, if you pass parameters by reference, the DLL's functions can read and write to those spaces.