I'm not an expert so I asked ChatGPT to search other alternatives for me:

ChatGPT misses again!

• Doxybook2 is no longer maintained.
• docfx has no C++ support. We'd have to manually convert Doxygen output.
• Standardese, maybe. It hasn't released in about ~4 years.
• cldoc last released in 2018.
• Natural Docs, maybe, but it requires Mono on Linux/macOS. And is mostly focused on C# and doesn't claim full support for C++.

Doxygen might be the best option from all the information we have so far :)

At the very least, most other solutions will use Doxygen as a base so I'll try and set it up

I don't have any opinion on the C++ documentation generation, but we use mkdocs at PyIceberg, and it works really well: https://github.com/apache/iceberg-python/tree/main/mkdocs

How does mkdocs compare to Sphinx? Sphinx really has excellent cross-referencing capabilities (to API docs, to glossary, to other pages, to index references, even to other Spinx docs).

@pitrou It is pretty similar, mkdocs feels a bit more modern to me. Referencing the Python docs works pretty well: https://py.iceberg.apache.org/reference/pyiceberg/io/

How does it work for C++ though? I see a few random plugins (like cxxdox) but I'm not confident in them vs Doxygen. (I also don't see from a bit of searching how mkdocs handles the equivalent of a Sphinx :cpp:class or :py:meth: etc. which is one of the best features of Sphinx for me.)