There is more to GSL than XML processing.  GSL was used to write ZeroMQ along with many other pieces of software.  GSL can also be used to write FSM (finite state machines) and an earlier variant called Libero, was used to write the very well regarded, Xitami multithreaded web server.<p>I just installed it yesterday so haven&#x27;t been able to fully suss out how I will use it.<p>Hintjens also wrote the CLASS style guide&#x2F; subset of C usage which is used for ZeroMQ etc. I don&#x27;t program in C, thus, can&#x27;t offer an informed opinion about it - but perhaps another HN&#x27;er can chime in on the quality of it.