There is a lot of RPC technology for C/C++.
For not using JNI, here are some library which support native C/C++.
thrift: open-sourced by facebook, and it is used by Taobao. Support multiple language, but NOT support dynamic typing,
Avro：used by hadoop， supply serialization and RPC for many language.
But sadly, it hava NOT supply RPC framework for C/C++.
MessagePack: It seems to be useful and easy, also support dynamic typing and multiple language.
Here is info at http://msgpack.org/.
protocol buffer: open-sourced by google. But it NOT offically provide RPC framework. Maybe you can find some third part.
RCF: Only for C++. Here is info at http://deltavsoft.com/.