5 Best Eclipse Plugins: #1 (Eclox with Doxygen, Graphviz and Mscgen)

The #1 award in my list goes to Eclox+Doxygen+Graphviz+Mscgen. Yes, it is a single Eclipse plugin (Eclox) for Doxygen, and with two other powerful tools.  It solves a typical engineering problem: “How to document my project? And how to keep it up-to-date?”.

Like many other engineers, I do not like to write documentation. Because it is painful. I want to write code and program. Writing documentation for it should be fun too. And it should solve the problem that the documentation does not match what has been implemented. I’m a big fan of the ‘single source’ concept: information has to be in a single place, and not copied and distributed among different places. And here my #1 helps me doing this.

eclox and eclipse

eclox and eclipse

In a traditional way the following flow is used:

  1. Create a design, specify and document the API
  2. Implement the software
  3. Write the user documentation
  4. Ship it
  5. Maintain and ship; and again, and again, and …

The problem starts with the fact, that rarely the implementation matches the initial design. It even gets worse after a few maintenance cycles: it is very hard to keep the documentation in sync with the actual implementation and project sources. And the user documentation will be easily out of sync too :-(.

It is already hard to write good documented code, and writing good source comments is an art on its own. Why not using the my precious source documentation in the sources and use it for the ‘written’ documentation? This is where I use Doxygen, GraphViz, Mscgen and the Eclipse Eclox plugin, all of them open source.

Doxygen is a compiler which generates documentation out of source files. Graphviz is a package to draw diagrams and graphs. Mscgen is similar to Graphviz, but simpler and optimized for message sequence diagrams. And Eclox is an Eclipse plugin which integrates everything into Eclipse.


Here are the links to download the needed tools:

  1. Doxygen: http://www.stack.nl/~dimitri/doxygen/ or www.doxygen.org
  2. Graphviz: http://www.graphviz.org
  3. Mscgen: http://www.mcternan.me.uk/mscgen/

NOTE: As of Feb 2018, the doxygen Eclox project has been moved to the following site: https://anb0s.github.io/eclox/. I recommend that you download the zip file from that site. For CodeWarrior for MCU I’m using the 0.8 version and that one works well. As CW for MCU 11.0 and earlier use an older Eclipse version, do *not* upgrade doxygen to a later version: only use 0.8 version.

In case you still need the 0.8.0 or earlier version: I have them available on SourceForge: https://sourceforge.net/projects/mcuoneclipse/files/Eclipse%20Plugins/Eclox/

Doxygen is required, Graphviz highly recommended, and Mscgen is optional.

In Eclipse, use the menu Help > Install New Software or the Market Place (https://marketplace.eclipse.org/content/eclox) and point to the directory where you have extracted the file.

If using CodeWarrior for MCU 10.x or 11.x (Eclipse 4.2 Juno based), then only use the 0.8 version:

Installing Eclox

Installing Eclox


With Doxygen my project sources *are* the documentation. Doxygen is using the comments in the code to generate the documentation. It is a compiler which compiles source (or text) files and extracts the embedded information. It supports many programming languages (C, C++, Java, …), and different output formats: HTML and PDF are very popular ones.

Doxygen is able to generate documentation from standard sources. But there are multiple ways of using special commenting styles to extend the information created. The Doxygen documentation lists different commenting styles.

With this, the following source is compiled by Doxygen:

/*! Masks for LEDs, this is an enum, and the values are power of two to make it
     possible to build masks. The bit number also indicates the port bit number.
      Make sure compiler treats enum's efficient (e.g. as unsigned char, as enum
      by ANSI standard is int). */
  typedef enum {
    LED_0 = (1<<0), /*< Bit0 of port for LED0 */
    LED_1 = (1<<1), /*< Bit1 of port for LED1 */
    LED_2 = (1<<2), /*< Bit2 of port for LED2 */
    LED_3 = (1<<3)  /*< Bit3 of port for LED3 */
} LED_Set;

It produces the following HTML output documentation:

enum LED_Set HTML Documentation

enum LED_Set HTML Documentation

Another example is to document functions with their parameters:

 * \brief Switches on a set of LED.
 * \param[in] Leds The set of LED to be switched on.
void LED_On(LED_Set Leds);

void LED_On(LED_Set Leds) {
  /*! \todo implement function */

The corresponding HTML documentation will look like this:

LED_On() Documentation

LED_On() Documentation

Note the \todo with will automatically added to a ‘To Do’ list in the documentation:

Todo List

Todo List


Graphviz is open source software to create graphs using the dot language. Dot code can be used with Doxygen. With the dot language I define nodes and edges, and the tool will place them automatically. For example I can define a graph with following dot code (example from the dot guide):

digraph G {
main -> parse -> execute;
main -> init;
main -> cleanup;
execute -> make_string;
execute -> printf
init -> make_string;
main -> printf;
execute -> compare;

This then will create the following graph (source: dot guide):

small dot graph

small dot graph

The dot language makes it easy to create machine generated graphs too. That way dot is used in many other tools as visualization tool. And Doxygen is using of dot to create dependency graphs:

Dependency Graph

Dependency Graph

A nice feature is as well that the nodes have hyperlinks: click on a node an it jumps to the source file :-).

I’m using dot in my sources to enrich the documentation with graphs (a pictures may say more than 1000 words). Below is an example Doxygen/dot code:

/*! \brief Key scan routine which implements the state machine.
digraph example_api_graph {
node [shape=box];
DBNC_KEY_IDLE    [fillcolor=lightblue,style=filled,label="DBNC_KEY_IDLE" ];
DBNC_KEY_PRESSED [fillcolor=lightblue,style=filled,label="DBNC_KEY_PRESSED" ];
DBNC_KEY_RELEASE [fillcolor=lightblue,style=filled,label="DBNC_KEY_WAIT_RELEASE"];

This will generate the following output:

debounce graph

Debounce graph


Mscgen is similar to Graphviz, but specialized for Message Sequence Charts (hence the Msc in its name). With Mscgen I can add following doxygen/msc code:

arcgradient = 8;
a [label="Client"],b [label="Server"];
a-xb [label="get accel"];
a=>b [label="get accel"];
a<=b [label="ack"];
a<=b [label="accel data"];

This will create following message sequence diagram into my documentation:

Mscgen Example Chart

Mscgen Example Chart

Mscgen is ideal for any communication flow diagrams and greatly simplify and enhance my documentation.


All of above can be used without any IDE. But it is a lot of more fun within the Eclipse framework. And here is where Eclox comes into play: Eclox is a plugin which integrates Doxygen (and all above tools) into Eclipse and makes it really easy to use:

  • Seamless build integration
  • Editor coloring for Doxygen comments
  • User interface for Doxygen configuration files
  • Editor integration with automatic commenting
  • Warning/Error parser
  • Wizard to create configuration files
eclox and eclipse

Eclox and Eclipse

Eclox Plugin

Eclox automatically detects an existing Doxygen installation and reports it in the Preferences:

Doxygen Version

Doxygen Version

In case this fails, then this link gives some guidance how to set the settings in a manual way.

Syntax Coloring

Eclox adds a Doxygen workspace default editor to the system:

Doxygen Workspace default

Doxygen Workspace default

With this Doxygen comments are in blue color:

Doxygen source coloring

Doxygen source coloring

Doxygen Auto Comments

What is really cool: Eclox automatically adds comments in Doxgen format. For example I have this in my source:

int CalcPos(int currPos, int steps);

Then I simply can start a Doxygen comment (e.g. with /**) and press ENTER:

* @param currPos
* @param steps
* @return

int CalcPos(int currPos, int steps);

It automatically creates the comment block for me with parameters and return type, so I only need to fill in the content :-).

New Doxygen Configuration File Wizard

Doxygen needs a textual configuration file. Eclox adds a wizard to create one using the menu File > New > Other > Doxyfile:

Creating New DoxyFile

Creating New DoxyFile


The Doxygen configuration file (Doxyfile) is a simple text file which has comments in it to explain the settings:

# Doxyfile 1.7.2

# This file describes the settings to be used by the documentation system
# doxygen (www.doxygen.org) for a project.
# All text after a hash (#) is considered a comment and will be ignored.
# The format is:
#       TAG = value [value, ...]
# For lists items can also be appended using:
#       TAG += value [value, ...]
# Values that contain spaces should be placed between quotes (" ").

# Project related configuration options

# This tag specifies the encoding used for all characters in the config file
# that follow. The default is UTF-8 which is also the encoding used for all
# text before the first occurrence of this tag. Doxygen uses libiconv (or the
# iconv built into libc) for the transcoding. See
# http://www.gnu.org/software/libiconv for the list of possible encodings.


# The PROJECT_NAME tag is a single word (or a sequence of words surrounded
# by quotes) that should identify the project.


# The PROJECT_NUMBER tag can be used to enter a project or revision number.
# This could be handy for archiving the generated documentation or
# if some version control system is used.


Doxyfile Editor

Doxygen needs a text configuration file (the Doxyfile). With Eclox there is an editor view for that file:

Eclox doxyfile editor

Eclox doxyfile editor

The ‘Basic’ tab of that editor view gives access to the most important settings: The Input directories (I list here all the source directories I want to process), the Output Formats (I use mostly HTML. For PDF I usually select RTF or LaTeX), Diagrams and Mode selection.

There is a bug in the Eclox plugin: it looses the language settings for the ‘Optimize results for:’ settings. But that’s not a big deal.

The ‘Advanced’ Tab gives access to all settings:

Doxyfile Advanced Tab

Doxyfile Advanced Tab

Compiling the documentation

Eclox adds a toolbar button:

Eclox toolbar button

Eclox toolbar button

The button automatically selects the Doxyfile of the current project. Otherwise it is possible to select a different Doxyfile.

Generating the documentation is like normally compiling source files: the Doxygen compiler reports what is going on to the Console View, and warnings/errors are reported in the Problems View.

Other Documentation

It is possible to document things outside the source files. There are many different commands, \mainpage the most important one: it defines the main entry point of the documentation. Using \page and \section is is possible to organize the documentation, and \ref is used to reference labels:

Mainpage File with links to other files/pages

Mainpage File with links to other files/pages

If using HTML, then the main entry point for the documentation is the index.html. Eclipse comes with a built in web browser which can be used to open that file. Or use any other HTML viewer:

index.html as documenation entry point

index.html as documentation entry point


The combination of Eclipse+Eclox+Doxygen+Graphviz simplifies my life: it makes documentation easy to generate. And it allows me to use a ‘single source’ approach: the sources are the documentation :-).

Happy Ecloxing 🙂



55 thoughts on “5 Best Eclipse Plugins: #1 (Eclox with Doxygen, Graphviz and Mscgen)

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  3. Pingback: 5 Best Eclipse Plugins: #1 (Eclox with Doxygen, Graphviz and … | Laughing

  4. Thanks for explaining this. My work many times is taking a project that people are having problems with and solving those problems. This is a quick and easy way to get the high level overview of what is going on without reading every single C file.


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  8. Is there a way to integrate the generated HTML documentation into Eclipse when I press F1? I have to code a library containing doxygen documentation and I want other developers to access that documentation as easyly as possible.


  9. Hi all,
    After installed Doxygen, Graphviz, and Mscgen, I point Codewarrior 10.6 to the Eclox update side
    and I get error below

    Unable to read repository at download.gna.org/eclox/update.
    Unable to read repository at download.gna.org/eclox/update.
    download.gna.org/eclox/update is not a valid repository location.

    any idea?



    • Hi Biet,
      I just had to add Eclox to my new Eclipse Kepler installation, and that worked fine for me (download.gna.org/eclox/update/). Can you verify that you have internet access? Maybe the server was down for a short period. Can you retry it?


      • Hi Enrich,
        Thanks for reply. I am just be able to install it on Codewarrior 10.3 but not on Codewarrior 10.6, getting the same problem that I have before. I am very sure that it is CW 10.6 problem.


        • Hi Biet,

          I just re-tried it with my MCU10.6, and I can install and use Eclox without any problems?

          I think there must be something wrong with your machine or installation.



        • Can you download one of the packages present on home.gna.org/eclox/#packages and then update Eclipse from the package?
          That way no network access is needed.
          I hope this helps,



        • Another thought I have: do you have a strange network configuration (configured a proxy in MCU10.6)? Somehow it is not able to access the internet?



  10. Excellent post. I was checking constantly this weblog and I’m impressed!

    Extremely useful information specially the final phase 🙂 I handle such info
    a lot. I was seeking this certain inf for a very long time.
    Thank you and good luck.


  11. Holy shit 🙂

    I never came around to learn more about doxygen, but it always was on my todo list. Your explanation here has helped me a great deal and I am really glad I found it.

    I am installing all the necessary tools and the plugin right now and will use them to better document my master thesis. The professors will thank you for leading me to Eclox 🙂


    • Yes, and I always pass a ‘thank you’ to my students if they document with doxygen. Actually using doxygen is mandatory in my embedded systems programming course I teach 🙂


  12. Dear all,
    I have installed all plugins, but after runnig I have got this error :
    error: problems opening map file C:/Users/Nadia/workspace/C++/html/structunitex_1_1virtualfile_1_1_v_f_s___i_n_o_d_e____coll__graph.map for inclusion in the docs!
    If you installed Graphviz/dot after a previous failing run,
    try deleting the output directory and rerun doxygen.

    Please I need your help,


  13. This article is really about Eclox with the proper additional plugins necessary for it to work fully – or almost fully, so I was a bit disappointed.

    It would be great if it generated PDF documentation by clicking the @. It doesn’t. You first need to install LATEX (full seems to be required) and maybe 10GB to 20GB later you can generate it outside of Eclox. But isn’t that the sort of thing that an IDE is supposed to do for you? With a bit of polishing up and optimizing defaults for newbies it has potential to be a nice development tool like javadoc.


    • Doxygen is really primarily about generating HTML (which works great). PDF is either over .rtf of LaTeX. But LaTeX is really something for advanced users. So you might be better to take the .rtf and then convert the file into a pdf in a separate step.


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  16. I’d like to use eclox for my Java code (Android Apps) but every time when i try to a doxyfile i get the error Doxygen Error
    An error occured while running doxyge.eclox.core.doxygen.RunException:


      • I also use Juno. At the moment I created the Doxyfile with Doxywizard and copied the Doxywizard into the project. In this way it works. But for a new project i need to create the doxyfile with doxywizard again.


        • Ok, I see. Yes, you need to create that .doxyfile somehow first. What I usually do is a copy it from a previous project, and then change it. That way I do not need to run the doxywizard again.


  17. Hi Erich,
    After installed Doxygen, Graphviz, Mscgen and Eclox update
    When I compile the documentation
    I have this warning message:
    Warning: the dot tool could not be found at C:\ProgramFiles\Graphviz2.38\bin
    The dot.exe is installed in C:\ProgramFiles\Graphviz2.38\bin

    What can I do ?

    Raul Cortes


    • Hi Carlos,
      it should have been automatically added to the Windows PATH environment variable by the Graphviz installer. Can you check if it is present in the PATH of your windows? If not, you need to add it manually there.
      I hope this helps.


  18. Hmmm – a puzzle. I’ve just installed these components. In some places the cool Eclox auto comment feature you describe works. On other places it does not work. Some experiments suggest it does not work inside an #if #endif block. Any knowledge or work arounds for this?


    • Hi Charles,
      yes, that auto-comment only seems to work in some places, and not for every function. I do not have a workaround for this. I think the implementation of the auto-comment only covers the most common cases, and as the Eclox plugin is now unmaintained for several years, I doubt that it will be fixed. It is a shame that nobody has been able to pick up that plugin work :-(.


  19. These tools work OK on some small projects. As I try to run Doxygen on a medium-sized project I get “*** Build aborted! An internal error occurred during: “Doxygen Build [/HBM1_GPRS2/Documentation/doxygen/pex.doxyfile]”. and a dialog box says “An internal error occurred during: “Doxygen Build [/HBM1_GPRS2/Documentation/doxygen/pex.doxyfile]”.
    endRule without matching beginRule: L/HBM1_GPRS2/Documentation/doxygen/pex.doxyfile”

    Google suggests these originate within Eclipse rather than being specific to Doxygen. Is there any prospect of resolving this? I am using Kepler. Doxygen has been reporting many warnings such as the following – I don’t know if they are related:
    “C:/Freescale/EWorkspace2/HBM1_GPRS2/Generated_Code/WDog1.c:105: warning: Unsupported xml/html tag found”


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        • No, Eclox won’t change your sources. Eclox is a front end for doxygen in Eclipse. But doxygen can create documentation from your sources even if it does not have special doxygen comments in it. The doxygen comments help the tool, but it works to a certain degree as well without it.


  21. Hi all,
    Thanks Erich Styger for the reply…

    I have large Source Code ( c and java ) adding doxygen comments manually will be time consuming, Looking for a tool which can add doxygen comments in my source code and later i can fill the description in it (@brief’s before function , macro , structures etc…),
    Is there any such tools which can add doxygen comment in the source code.



    • The Eclox plugin has a functionality which adds the @brief etc. But you have to put the ‘enter’ key first, so it is interactive. I’m not aware of a tool which does what you want.


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  23. Hi! I’m trying to use eclox plugin in CW 10.4. I install eclox 0.8, but when I try to create doxyfile It fails saying “An error occured while running doxygen.eclox.core.doxygen.RunException:”

    If I create doxyfile with doxywizard and add to my project and execute, It fails again saying “error: configuration file … not found!”

    I update eclox to 0.10 but the result is the same.


    • CW 10.4 is very old. Have you tried it in CW 10.7? I would need to check, but as your CodeWarrior version is very old, you might have better luck if you would try an older Eclox version? Or Switch to CW for MCU 10.7?


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