Apache Celix is an implementation of the OSGi specification adapted to C and C++ (C++11). It is a provides a framework to develop (dynamic) modular software applications using component and/or service-oriented programming.
For information how to build Apache Celix see Building Apache Celix
For an introduction into Apache Celix see Apache Celix Intro
For a guide how to start writing your own bundles and services see Getting Started Guide