How to output variables each time step for EnergyPlus for co-simulation with external script?

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Basically i need to output variables (zone air temperature, zone air humidity, etc) each time step from EnergyPlus, instead of at the end of whole simulation. By that way, external scrip can read the outputs from EnergyPlus each timestep, and make some changes by external scripts and send back to EnergyPlus for next timestep calculations. I know it can be done similarly by EMS objects in EnergyPlus. It is not easy to implement my control logics through EMS.
But instead I plan to build the coupling through external script: Python/C/C++.