CPPWiki is a ridiculously simple Wiki written in C++ using a slightly modified ServerMe.H (this "fork" is temporary, at some point i'll merge the changes... at some point) to provide a standalone wiki - all you need to use it is to get the executable, place it in a directory of its own and run it. Then point your browser to http://127.0.0.1:8088/ (the port can be changed by recompiling the code).
The wiki saves all of its pages in text files under a pages
subdirectory. It has no support for formatting beyond anything
between [ and ] that is made up of latin letters, numbers, _ and
- (but no spaces) being treated as a page link.
It is not meant to be used on the open internet and i mainly made it to use it via the web browser in Steam's overlay to take notes for games.
Note that CPPWiki uses the GET method for forms instead of POST (ServerMe.H cannot parse POST requests) and some browsers may not support large GET requests (however i tested it with several browsers including Firefox, Chrome and Edge and all worked with 60K+ of textual data which should be more than enough for the simple note-taking that i made it for).
License is zlib, but as always, consider this.