Doxygen

Doxygen

File:Doxygen.png
Developer(s)	Dimitri van Heesch
Initial release	26 October 1997 (1997-10-26)
Stable release	1.8.11 / 30 December 2015 (2015-12-30)
Written in	C++
Operating system	Cross-platform
Type	Documentation generator
License	GNU General Public License
Website	doxygen.org

Doxygen (/ˈdɒksidʒən/ DOK-see-jən) is a documentation generator, a tool for writing software reference documentation. The documentation is written within code, and is thus relatively easy to keep up to date. Doxygen can cross reference documentation and code, so that the reader of a document can easily refer to the actual code.

Doxygen is free software, released under the terms of the GNU General Public License.

Design

Like Javadoc, Doxygen extracts documentation from source file comments. In addition to the Javadoc syntax, Doxygen supports the documentation tags used in the Qt toolkit and can generate output in HyperText Markup Language (HTML) as well as in Microsoft Compiled HTML Help (CHM), Rich Text Format (RTF), Portable Document Format (PDF), LaTeX, PostScript or man pages.

Uses

Programming languages supported by Doxygen include C, C++, C♯, Fortran, IDL, Java, Objective-C, Perl, PHP, Python, Tcl, VHDL and others.

It runs on most Unix-like systems, Mac OS X and Windows.

The first version of Doxygen borrowed code from an early version of DOC++ (developed by Roland Wunderling and Malte Zöckler at Zuse Institute Berlin); later, the Doxygen code was rewritten by Dimitri van Heesch.

Example code

File:Doxygen ouput.png

A screenshot of what the output would look like in HTML

The generic syntax of documentation comments is to start a comment with an extra asterisk after the leading comment delimiter '/*':

/**
<A short one line description>

<Longer description>
<May span multiple lines or paragraphs as needed>

@param  Description of method's or function's input parameter
@param  ...
@return Description of the return value
*/

Many programmers like to mark the start of each line with space-asterisk-space, as follows, but that is not necessary.

/**
 * <A short one line description>
 *
 * <Longer description>
 * <May span multiple lines or paragraphs as needed>
 *
 * @param  Description of method's or function's input parameter
 * @param  ...
 * @return Description of the return value
 */

Many programmers avoid using C-style comments and instead use C++ style single line comments. Doxygen accepts comments with additional slash as Doxygen comments.

/// <A short one line description>
///
/// <Longer description>
/// <May span multiple lines or paragraphs as needed>
///
/// @param  Description of method's or function's input parameter
/// @param  ...
/// @return Description of the return value

The following illustrates how a C++ source file can be documented.

/**
 * @file
 * @author  John Doe <jdoe@example.com>
 * @version 1.0
 *
 * @section LICENSE
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of
 * the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details at
 * https://www.gnu.org/copyleft/gpl.html
 *
 * @section DESCRIPTION
 *
 * The time class represents a moment of time.
 */

class Time {

    public:

       /**
        * Constructor that sets the time to a given value.
        *
        * @param timemillis Number of milliseconds
        *        passed since Jan 1, 1970.
        */
       Time (int timemillis) {
           // the code
       }

       /**
        * Get the current time.
        *
        * @return A time object set to the current time.
        */
       static Time now () {
           // the code
       }
};

An alternative approach for documenting parameters is shown below. It will produce the same documentation.

       /**
        * Constructor that sets the time to a given value.
        */
       Time (int timemillis ///< Number of milliseconds passed since Jan 1, 1970.>
            )
       {
           // the code
       }

Richer markup is also possible. For instance, add equations using LaTeX commands:

/**
 *
 * An inline equation @f$ e^{\pi i}+1 = 0 @f$
 *
 * A displayed equation: @f[ e^{\pi i}+1 = 0 @f]
 *
 */

See also

• Comparison of documentation generators
• Graphviz
• Mscgen
• API Writer

External links

• Official website
• Doxygen on SourceForge.net
• Doxygen at Freecode
• Doxygen commands