Bestpractice for receiving external commands

What is the best way to control the scene rendering by an external application?

I want to use data form a sensor to rotate one of my cameras, as the sensor has to be readout much faster than the framerate allows, the readout and processing has to be done externally in c++.

All the Information I've found to this topic is some years old and probably outdated. Any help or pointers in to the right direction would be highly appreciated.