If you are an open-source developer and want to release your project to the public, you may consider publishing source-code documentation for the project. In cases where you are trying to read source code written by others, it will also be helpful if you can get a "bird-eye" view of the otherwise cryptic source code.
In Linux, doxygen is the de facto standard tool for automatically generating cross-reference documentation from annotated source code. It supports major programming languages including C/C++, Objective-C, C#, PHP, Java and Python.
Using doxygen, you can auto-generate API reference documentation of source code, in HTML or Latex format. You can also visualize class dependency and the relationship between different source files.
In this tutorial, I will explain how to automatically generate documentation from source code in Linux by using doxygen.
Install Doxygen on Linux
To install doxygen on Ubuntu, Mint or Debian:
$ sudo apt-get install graphviz
To install doxygen on CentOS, Fedora or RHEL:
$ sudo yum install graphviz
Generate Documentation from Source code with Doxygen
To generate documentation of source code, proceed as follows.
First, generate a project-specific doxygen configuration file:
The above command will generate a template configuration file for a particular project.
Among others, you can edit the following options in the configuration file.
# document all entities in the project. EXTRACT_ALL = YES # document all static members of a file. EXTRACT_STATIC = YES # specify the root directory that contains the project's source files. INPUT = /home/xmodulo/source # search sub-directories for all source files. RECURSIVE = YES # include the body of functions and classes in the documentation. INLINE_SOURCES = YES # generate visualization graph by using dot program (part of graphviz package). HAVE_DOT = YES
Now go ahead and run doxygen with the configuration file.
Documentations are generated in both HTML and Latex formats, and stored in ./html and ./latex directories respectively.
To browse the HTML-formatted documentation, run the following.
$ firefox index.html
Doxygen Documentation Screenshots
Here are several screenshots for doxygen outputs.
This shows a list of header files that are automatically categorized by topics.
This shows a list of classes, structs, unions and interfaces with descriptions.
This shows a source code browser listing all source files recursively in sub-directories.
If you click on a particular source file, you will see a page which shows dependency graph for the file, as well as documentation for all defined functions.
This shows a detailed view of function/macro definitions. Below the figure is shown the actual source code snippet that corresponds to this documented portion.
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