wikiqs is a wiki software written in C, intended for small wikis.
I did it just for fun and myself and it evolved over time. Nowadays, I am not convinced that a threaded FastCGI architecture is really worth it, and if I were to start it again, I would focus more on sandboxing and privilege separation (ideas like pledge(2) etc.). In order to improve the code I am considering a rewrite in C++ or at least refactoring, since the code was also often used as a playground for various ideas. Until then there is not much value in publishing the code.
-Support for user accounts. Passwords are stored using PBKDF2.
-Support for several storage backends. This site is using sqlite. Other methods can be added with not too much effort.
-Fine-grained permission system.
-Handles ETAG request headers
-All user input is escaped against XSS attacks by default.
-All POST requests are centrally protected against XSRF attacks.