It is a great article if you want to get into the art of binding to C libraries:
This article gives an overview over problems, solutions and guidelines for writing an Ada binding for a C library. It summarizes experiences I made while implementing OpenCLAda and OpenGLAda. Code examples are taken from those projects.
The Ada code examples shown here are written in Ada 2005. Note that you can import C functions somewhat nicer in Ada 2012.
Since I’m a complete binding virgin, I would like to personally thank Felix Krause for writing this article. I’ve learned A LOT from reading it. I also added the article to the Ada-DK wiki Resources page.