There are a number of types of documentation available for Xapian.
User documentation that explains how people will use Xapian, typically either as a “full worked example”, or as a deep dive into a particular feature.
API documentation, which is built from specially-formatted comments in Xapian’s C++ header files. This allows people writing code that uses Xapian to check on details of the classes and methods they are using, as well as to explore what features there are in Xapian.
There is also some developer documentation available elsewhere, particularly in the main Xapian source repository – look in particular in
xapian-core/docs. Some of this is being migrated to the developer guide. (Some is also being migrated to the user guide.)
The Xapian wiki also contains information, including links to articles and talks that people have written about using Xapian in various ways. Although this isn’t always official Xapian documentation, it may be helpful. Some of it may now be quite out of date, so if something you find there doesn’t work, you may want to check the official documentation to see if you can figure out how to change the advice or code you find to work with a recent version of Xapian.
Omega, a standalone indexing and web search tool built using Xapian, has its own documentation bundled with its source code, and available on our website.
The language bindings, which allow you to use Xapian from programming languages others than C++, have their own documentation which mostly focusses on ways that the API is different from C++ in those languages.
Building the documentation¶
The user guide and developers guide can both be built using Sphinx;
there is more information in a
README.md in each repository.
If you’re building from a clone of Xapian, then the API docs will be built automatically as part of building Xapian. (If you’ve downloaded a source tarball, then the API docs will already have been built for you.) The API docs of the latest release are also available on the Xapian website, along with some of the developer documentation that isn’t in this developer guide.
Similarly, documentation for Omega and the bindings will be built when you build them from source, and is also available online.
Updating the documentation¶
As you work on changes to Xapian, it’s important to write or update documentation so people will know how to use your work. Looking through the list of documentation above, you can see there are a number of places where you could add helpful information. The main ones are:
The user guide, which is where most new users expect to learn how to use Xapian.
The API documentation, in doxygen comments in the source code.
The developer guide, if you make changes which future developers will need to know.
Note that you can also provide information to future developers in code comments, and in the commit messages you write. For many types of information, they are more convenient for other developers to find when they need. Try to add information where you yourself would expect to find it.
Don’t worry about getting the words exactly right, particularly if English isn’t your first language. If you can get down the information that needs to be there, someone else can tidy up the language if necessary.
PDF versions of docs¶
If you want PDF versions of the API documentation, you’ll need to install some more tools:
- gs (part of Ghostscript)
- pdflatex (in texlive-latex-base on Debian/Ubuntu)
- epstopdf (in texlive-extra-utils on Debian/Ubuntu)
- makeindex (in texlive-binaries on Debian/Ubuntu, or texlive-base-bin for older releases)
Note that pdflatex, epstopdf, gs, and makeindex must all currently be on your path (as specified by the environment variable PATH), since doxygen will look for them there.
For a recent version of Debian or Ubuntu, this command should work:
apt-get install ghostscript texlive-latex-base texlive-extra-utils \ texlive-binaries texlive-fonts-extra texlive-fonts-recommended \ texlive-latex-extra texlive-latex-recommended
On macOS, you can install MacTeX.
Once you’ve got the extra tools you need, you can build the PDF documentation:
(cd xapian-core && make -C docs apidoc.pdf)