How To Help Developing Lazarus

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Revision as of 13:17, 17 July 2006 by Borut (talk | contribs) (Widgetsets ("interfaces"))

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Prerequisites to developing Lazarus

There are two things to note:

  • You should have the latest release of FreePascal compiler (FPC) or a recent SVN version (i.e. a later version) of it. For obtaining FPC, see FreePascal download.
  • You must have the very latest Lazarus from SVN. For obtaining it, see Getting Lazarus via SVN.

Development areas

So now you have the latest version of Lazarus and wish to start improving it, but are asking yourself "where do I begin?" Well, that depends.

Known bugs

If you don't have any particular woes about Lazarus but just want to help, then I would recommend looking at the bug list Bug Tracker find a bug that you think you can fix, and start hacking. The Lazarus team has prioritized the open bugs in the Road To 1.0.


Lazarus needs more documentation! If you don't want to fix a bug you can help by writing documentation. Even this page is a work in progress. If you have useful information to add, or if you see mistakes, please feel free to improve the contents of this page.

Look at Lazarus Documentation Editor and LCL Documentation Roadmap for some help on how to and a list of units to be documented.

The on-line IDE help is gradually being created as a part of the wiki. Recently a lot of stub pages of the Lazarus IDE documentation about the IDE windows have been added. When working in IDE, if you need help, press F1. You will be presented a help wiki page (possibly empty or incomplete). Improve it, if you have the relevant knowledge.


See these links: Extending the IDE, Road To 1.0.

Widgetsets ("interfaces")

A widgetset (WS) is the "glue code" between the LCL code parts that are independent of the target operating system and the target operating system itself. For each supported target OS, the corresponding WS units are to be found in one of the subdirectories under the C:\Lazarus\lcl\interfaces\.

Here is an outline of the steps one should follow, in order to improve a widgetset (description provided by Mattias Gärtner on the Lazarus mailing list on 2006-07-15). When making changes to a WS, it is not necessary to rebuild everything (Lazarus including the IDE), in order to test the efects of the changes. Proceed as follows:

* Create your testbed project (a small program
  which should contain the testing code for your WS changes);
* Setup the keyboard shortcuts for 'Build Lazarus' and 'Configure Build Lazarus' 
  (in IDE, go to Editor Options/Keymapping);
 * Configure "Build Lazarus" to only build the LCL 
  (in IDE, go to Tools/Configure "Build Lazarus");
  * Make your improvement in the WS code;
  * Build Lazarus (in IDE, go to Tools/Build Lazarus 
    - this only rebuilds the LCL, which rebuilds also the selected WS);
  * Now compile your testbed project;
  * Run and debug your program;
 until no errors are found in your change;
 * Reconfigure "Build Lazarus" to build all 
   (in IDE, go again to Tools/Configure "Build Lazarus");
 * Build Lazarus and test the IDE;
until no errors/degradation due to your changes are found in IDE;
* Create a patch and send it (see further below for details).

How to submit your changes?

You will need to make a "patch" (see Creating A Patch) and send it to the mailing list (maximum size 40kB) or the mailbox for patches

Need more help?

If you have any question you can ask them on one of the following places:

  • The Lazarus Mailing list (see Mailing list)
  • The #lazarus-ide IRC channel on