Doxygen

Doxygen is a tool that builds reference documentation from the comments written inside source code. It reads the code, collects details about classes, functions and variables, and turns them into browsable pages.

Doxygen parses your source files and the special comment blocks inside them. It then produces output such as HTML, PDF via LaTeX, Word via RTF and XML. It can also draw class hierarchy and collaboration diagrams, and it adds links between related parts of the code so readers can move from one item to the next.

• Output to HTML, PDF, RTF and XML
• Markdown support inside comments
• Cross-references and clickable links
• Class and collaboration diagrams
• Settings kept in a single configuration file

Doxygen suits developers and teams who want API documentation to stay close to the code it describes. It is a good fit for large C++ projects, and it also handles C, Python, Java, C# and several other languages that teams use alongside C++.

Doxygen is free and open source, released under the GPL license. It runs on your own machine, so you control where the output is stored and hosted. Setup happens through the configuration file, which can take some time to tune for big projects with many input folders.