What is the recommended approach for creating Erlang language bindings?

edit

The TCPROS protocol did not change for years. The only thing that had to be updated was the message generator because some old libraries and tools were deprecated and replaced by newer libraries.

I think although it might be more work and harder to implement, approach A will definitely be more robust and integrate better in Erlang. If you just want a quick solution, you can use a foreign function interface. But note that you first need to wrap the ROS C++ library into a C library to do that which can be quite cumbersome, too. Also, in that case you need to implement marshaling from Erlang data types to the corresponding C++ data types in order to transmit them with roscpp.