If you reach a bit over into IPC/RPC, rather than just linking, the options with decent IDL and cross language code generators start to increase quickly. For ex

If you reach a bit over into IPC/RPC, rather than just linking, the options with decent IDL and cross language code generators start to increase quickly. For example D-bus, or androids binder. Some even use grpc or thrift between processes on same machine. All of these are of course operating one or two abstraction levels up but are still good to consider.