Chapter 6. Documentation Tools
6.1.1. Doxygen Supported Output and Languages
- RTF (MS Word)
- Hyperlinked PDF
- Compressed HTML
- Unix man pages
- Objective -C
6.1.2. Getting Started
doxygen -g config-file. This creates a template configuration file that can be easily edited. The variable config-file is the name of the configuration file. If it is committed from the command it is called Doxyfile by default. Another useful option while creating the configuration file is the use of a minus sign (
-) as the file name. This is useful for scripting as it will cause Doxygen to attempt to read the configuration file from standard input (
TAGNAME = VALUE1 VALUE2...
doxywizard. If this is the preferred method of editing then documentation for this function can be found on the Doxywizard usage page of the Doxygen documentation website.
For small projects consisting mainly of C or C++ source and header files it is not required to change anything. However, if the project is large and consists of a source directory or tree, then assign the root directory or directories to the INPUT tag.
File patterns (for example,
*.h) can be added to this tag allowing only files that match one of the patterns to be parsed.
Setting this to
yes will allow recursive parsing of a source tree.
These are used to further fine-tune the files that are parsed by adding file patterns to avoid. For example, to omit all
test directories from a source tree, use
EXCLUDE_PATTERNS = */test/*.
When this is set to
yes, doxygen will pretend that everything in the source files is documented to give an idea of how a fully documented project would look. However, warnings regarding undocumented members will not be generated in this mode; set it back to
no when finished to correct this.
By setting the
SOURCE_BROWSER tag to
yes doxygen will generate a cross-reference to analyze a piece of software's definition in its source files with the documentation existing about it. These sources can also be included in the documentation by setting
6.1.3. Running Doxygen
xml, and / or
mandirectories in whichever directory doxygen is started in, containing the documentation for the corresponding filetype.
index.html in the
Doxygen writes a
Makefile into the
latex directory in order to make it easy to first compile the Latex documentation. To do this, use a recent teTeX distribution. What is contained in this directory depends on whether the
USE_PDFLATEX is set to
no. Where this is true, typing
make while in the
latex directory generates
refman.dvi. This can then be viewed with
xdvi or converted to
refman.ps by typing
make ps. Note that this requires
make ps_2on1prints two pages on one physical page. It is also possible to convert to a PDF if a ghostscript interpreter is installed by using the command
make pdf. Another valid command is
make pdf_2on1. When doing this set
yesas this will cause
Makefilewill only contain a target to build
This file is designed to import into Microsoft Word by combining the RTF output into a single file:
refman.rtf. Some information is encoded using fields but this can be shown by selecting all (
CTRL+A or Edit -> select all) and then right-click and select the
toggle fields option from the drop down menu.
The output into the
xml directory consists of a number of files, each compound gathered by doxygen, as well as an
index.xml. An XSLT script,
combine.xslt, is also created that is used to combine all the XML files into a single file. Along with this, two XML schema files are created,
index.xsd for the index file, and
compound.xsd for the compound files, which describe the possible elements, their attributes, and how they are structured.
MAN PAGE OUTPUT
The documentation from the
man directory can be viewed with the
man program after ensuring the
manpath has the correct man directory in the man path. Be aware that due to limitations with the man page format, information such as diagrams, cross-references and formulas will be lost.
6.1.4. Documenting the Sources
- First, ensure that
EXTRACT_ALLis set to
noso warnings are correctly generated and documentation is built properly. This allows doxygen to create documentation for documented members, files, classes and namespaces.
- There are two ways this documentation can be created:
- A special documentation block
- This comment block, containing additional marking so Doxygen knows it is part of the documentation, is in either C or C++. It consists of a brief description, or a detailed description. Both of these are optional. What is not optional, however, is the in body description. This then links together all the comment blocks found in the body of the method or function.
NoteWhile more than one brief or detailed description is allowed, this is not recommended as the order is not specified.The following will detail the ways in which a comment block can be marked as a detailed description:
There are three ways to add a brief description to documentation.
- C-style comment block, starting with two asterisks (*) in the JavaDoc style.
/** * ... documentation ... */
- C-style comment block using the Qt style, consisting of an exclamation mark (!) instead of an extra asterisk.
/*! * ... documentation ... */
- The beginning asterisks on the documentation lines can be left out in both cases if that is preferred.
- A blank beginning and end line in C++ also acceptable, with either three forward slashes or two forward slashes and an exclamation mark.
/// /// ... documentation ///or
//! //! ... documentation ... //!
- Alternatively, in order to make the comment blocks more visible a line of asterisks or forward slashes can be used.
///////////////////////////////////////////////// /// ... documentation ... /////////////////////////////////////////////////or
/********************************************//** * ... documentation ... ***********************************************/Note that the two forwards slashes at the end of the normal comment block start a special comment block.
Examples of how a documented piece of C++ code using the Qt style can be found on the Doxygen documentation websiteIt is also possible to have the documentation after members of a file, struct, union, class, or enum. To do this add a < marker in the comment block.\
- To add a brief description use
\briefabove one of the comment blocks. This brief section ends at the end of the paragraph and any further paragraphs are the detailed descriptions.
/*! \brief brief documentation. * brief documentation. * * detailed documentation. */
- By setting
yes, the brief description will only last until the first dot followed by a space or new line. Consequentially limiting the brief description to a single sentence.
/** Brief documentation. Detailed documentation continues * from here. */This can also be used with the above mentioned three-slash comment blocks (///).
- The third option is to use a special C++ style comment, ensuring this does not span more than one line.
/// Brief documentation. /** Detailed documentation. */or
//! Brief documentation. //! Detailed documentation //! starts hereThe blank line in the above example is required to separate the brief description and the detailed description, and
JAVADOC_AUTOBRIEFmust to be set to
int var; /*!< detailed description after the member */Or in a Qt style as:
int var; /**< detailed description after the member */or
int var; //!< detailed description after the member //!<or
int var; ///< detailed description after the member ///<For brief descriptions after a member use:
int var; //!< brief description after the memberor
int var; ///< brief description after the memberExamples of these and how the HTML is produced can be viewed on the Doxygen documentation website
- Documentation at other places
- While it is preferable to place documentation in front of the code it is documenting, at times it is only possible to put it in a different location, especially if a file is to be documented; after all it is impossible to place the documentation in front of a file. This is best avoided unless it is absolutely necessary as it can lead to some duplication of information.To do this it is important to have a structural command inside the documentation block. Structural commands start with a backslash (\) or an at-sign (@) for JavaDoc and are followed by one or more parameters.
/*! \class Test \brief A test class. A more detailed description of class. */In the above example the command
\classis used. This indicates that the comment block contains documentation for the class 'Test'. Others are:
\struct: document a C-struct
\union: document a union
\enum: document an enumeration type
\fn: document a function
\var: document a variable, typedef, or enum value
\def: document a #define
\typedef: document a type definition
\file: document a file
\namespace: document a namespace
\package: document a Java package
\interface: document an IDL interface
- Next, the contents of a special documentation block is parsed before being written to the HTML and / Latex output directories. This includes:
- Special commands are executed.
- Any white space and asterisks (*) are removed.
- Blank lines are taken as new paragraphs.
- Words are linked to their corresponding documentation. Where the word is preceded by a percent sign (%) the percent sign is removed and the word remains.
- Where certain patterns are found in the text, links to members are created. Examples of this can be found on the automatic link generation page on the Doxygen documentation website.
- When the documentation is for Latex, HTML tags are interpreted and converted to Latex equivalents. A list of supported HTML tags can be found on the HTML commands page on the Doxygen documentation website.