||This article for grammar, style, punctuation, use of undefined acronyms may require cleanup to meet Wikipedia's quality standards. (February 2011)|
Lazarus IDE 1.0 running on Mac OS X
|Stable release||1.0.8 / March 19, 2013|
|Type||RAD tool for Pascal and Object Pascal|
|License||GNU General Public License, GNU Lesser General Public License, and others|
Lazarus is a free cross-platform Integrated development environment (IDE) which provides a Delphi-like development experience for Pascal and Object Pascal software developers. It is developed for, and supported by, the Free Pascal compiler. Since early 2008, Lazarus has been available for Microsoft Windows, several Linux distributions, FreeBSD, and Mac OS X. Some versions were created even earlier, and Lazarus is a front end for the much older Free Pascal.
Cross-platform development 
Similar to Free Pascal’s run-time library, Lazarus provides a cross-platform application framework called the Lazarus Component Library (LCL), which provides a single, unified interface for programmers, with different platform-specific implementations. Using LCL, one can create applications in a write once, compile anywhere manner, unless system-dependent features are used explicitly.
As Free Pascal supports cross-compiling, Lazarus applications can be cross-compiled from Windows to Linux and FreeBSD, and vice versa. Compiling from Mac OS X to Windows, Linux and FreeBSD is possible. Cross-compiling to Mac OS X could be done for older (PowerPC) versions, but not for newer Intel versions, since Apple doesn't release the assembler and linker sources anymore.
Lazarus Component Library 
The standard application framework, Lazarus Component Library (LCL) was modeled after the Visual Component Library (VCL) in Delphi 6, but it is available for operating systems other than Windows. This is done by separating the definition of common widget classes and their widgetset-specific implementation. Support for each widget set is done by providing an interface which interacts directly with the widget set.
Currently (early 2011), the development status of widget toolkit interfaces is roughly as follows.
|Widget set||Supported Operating Systems||Status|
|Windows API, GDI||Windows||Mainstream use|
|Windows CE API, GDI||Windows CE||Mainstream use|
|GTK+ 1.2.x||Linux (via X11)||Deprecated|
|GTK+ 2.8+||Windows, Linux (X11 and framebuffer) and Mac OS X (via X11)||Mainstream use|
|GTK+ 3.x||As Gtk2||Planned as full rewrite|
|Qt 4.5+||Windows, Linux (X11 and framebuffer), Mac OS X||Mainstream use. Works in Windows, Linux, Mac OS X, Maemo, etc|
|Cocoa||Mac OS X||In progress|
|Carbon||Mac OS X||Mainstream use|
|fpGUI||Windows, Windows CE, Linux (via X11)||Initial stage|
|Lazarus Custom Drawn Controls||Android, Windows, Linux (via X11), Mac OS X||Initial stage|
The plan is to write a new GTK3 backend from scratch, because the GTK2 backend was no clean implementation and inherits GTK1 traits.
Database development 
Developers can install packages that allow Lazarus to support several databases. Programs can interact with databases through code or by components dropped on a form. The data-aware components represent fields and are connected by the correct setting of properties to a TDataSource, which represents a table, and to the database components, which may be TPSQLDatabase, TSQLiteDataSet, or equivalent.
The following databases are supported out of the box using the built in database components:
- dBase and FoxPro can be supported without the need for an external server or library through the TDbf component
- InterBase / Firebird. See 
- Microsoft SQL Server and Sybase_ASE. See 
- MySQL. See 
- ODBC databases. See 
- Oracle. See 
- PostgreSQL. See 
- SQLite. See 
Other components, such as Zeoslib, can also be used.
Differences from Delphi 
While resembling Delphi in many ways, there are a few limitations regarding the performance and feature set.
- Under Windows executable, by default, file size is somewhat larger than the Delphi (6/7) equivalent because debug information is included within Lazarus executables, instead of as separate files like Delphi. However, the 0.9.30 release introduces an external debug symbols feature. Lazarus program file size can be significantly reduced by using an external symbols file (it can be set in Compiler options), and also by using Strip
- Components for Delphi can be installed in Lazarus, but they must be converted, which can be complex. (2.4.x based 0.9.30 should make this easier)
- Missing important media libraries and widgets:
- Microsoft Office connectivity (popping up Excel with a simple table filled out works fine in 2.5.x trunk)
- Datasnap (not a publicly documented system, Embarcadero proprietary enterprise functionality)
- Networking is mostly available
- No support to directly call .NET libraries. On the other hand, it is possible to call Object Pascal code from .NET software. 
- COM support was missing from the 2.0.x series, but it was initially working in 2.2.0, and has matured since.
- Missing dynamically loadable packages support.
- Not 100 percent compatible with VCL. As mentioned previously this is by design, although the current LCL widget set should suffice for most applications. But this makes the deep repository of available VCL widgets inaccessible without conversion. The conversion effort mostly involves some editing, although there are a few fundamental differences. When porting, missing units in the libraries and COM support are a considerably bigger problem than incompatibilities between LCL and VCL.
Distribution and licensing 
Specifically, the LCL, which is statically built into the produced executables, is licensed under a modified version of the LGPL, granting extra permissions to allow it to be statically built into the produced software, including proprietary ones.
Note that installing a design-time package is equivalent to linking to the IDE. Thus, distributing the Lazarus IDE with a GPL-incompatible design-time package (e.g. the JEDI packages, which are licensed under the Mozilla Public License) pre-installed would cause a license violation. This does not prohibit proprietary packages from being developed with Lazarus, though.
Lazarus is officially distributed via Sourceforge.
|Version number||Release date||Platform||Comments|
|Old version, no longer supported: 0.0.5||January 2001||Windows||First release of component library|
|Old version, no longer supported: 0.1||January 2001||Windows||Redesign of component library to support platform-sensitive development for Linux and Windows using GTK+ and other widgetsets.|
|Old version, no longer supported: 0.5||January 30th, 2001||Windows, Linux||Bug fixes and new features supporting cross-platform development and project skeletons.|
|Old version, no longer supported: 0.8||October 9th, 2001||Windows, Linux||Codetools implemented, bug fixes.|
|Old version, no longer supported: 0.8.2||January 17th, 2002||Windows, Linux||Expanded find functions.|
|Old version, no longer supported: 0.8.4||August 19th, 2002||Windows, Linux||Improved graphics and font support, support for Delphi 6 syntax. Binary DFMs are now automatically converted to LFMs.|
|Old version, no longer supported: 0.8.5||October 26th, 2002||Windows, Linux||LCL decoupled from interfaces.|
|Old version, no longer supported: 0.9.0.3||September 4th, 2003||Linux||First release on Sourceforge|
|Old version, no longer supported: 0.9.1||February 27th, 2004||Windows, Linux||Support for packages, numerous added and enhanced properties.|
|Old version, no longer supported: 0.9.4||January 3rd, 2005||Windows||Threading support improved, oldest public version hosted at Sourceforge|
|Old version, no longer supported: 0.9.6||February 25th, 2005||Windows|
|Old version, no longer supported: 0.9.8||July 19th, 2005||Windows|
|Old version, no longer supported: 0.9.10||October 3rd, 2005||Windows, Mac OS X (PPC)||Bug fixes, extensibility of IDE improved, document editor for FPDoc files. Includes Free Pascal 2.0.1|
|Old version, no longer supported: 0.9.12||February 7th, 2006||Windows||New packages for database support, CGI applications and printing.|
|Old version, no longer supported: 0.9.14||April 2nd, 2006||Windows, Mac OS X (PPC), Linux||Bugfixes, more controls in the WinCE and Qt4 interface|
|Old version, no longer supported: 0.9.16||May 28th 2006||Windows, Mac OS X (PPC), Linux||Bug fixes, online help for IDE windows and for LCL applications, improvements to QT widgetset interface. Includes Free Pascal 2.0.2|
|Old version, no longer supported: 0.9.18||September 23rd, 2006||Windows, Mac OS X (PPC), Linux||Bugfixes, procedure list implemented, new command-line tool "lazbuild"|
|Old version, no longer supported: 0.9.20||November 5th 2006||Windows, Mac OS X (PPC), Linux||Bufixes, code folding implemented, QT widgetset improved.|
|Old version, no longer supported: 0.9.22||March 26th, 2007||Windows, Mac OS X (PPC), Linux||New components to write Windows services and Linux daemons, support for custom mouse cursors. Includes Free Pascal 2.0.4|
|Old version, no longer supported: 0.9.24||November 15th 2007||Windows, Mac OS X (Intel and PPC), Linux||First stable release for Win64, WinCE, and Intel-based Mac OS X. Improvements in Qt, Carbon, and Gtk2 widgetset interfaces. Customizable toolbar. Includes Free Pascal 2.2.0|
|Old version, no longer supported: 0.9.26||October 5th, 2008||Windows, Mac OS X (Intel and PPC), Linux||Internal graphic system was rewritten. LCL now uses Unicode strings encoded as UTF-8 on all platforms. FPDoc help in tooltips. First version to run natively using the Carbon widgetset on Mac OS X.|
|Old version, no longer supported: 0.9.26.2||March 13th, 2009||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes, improved icon support. Includes Free Pascal 2.2.2|
|Old version, no longer supported: 0.9.28||September 29th, 2009||Windows, Mac OS X (Intel and PPC), Linux||Improvements of editor and debugger including support for double-byte fonts such as Eastern, Japanese, Chinese, and Arabic, smaller file sizes of generated applications. Includes Free Pascal 2.2.4|
|Old version, no longer supported: 0.9.28.2||October 25th, 2009||Windows, Mac OS X (Intel and PPC), Linux||Mainly bug fixes.|
|Old version, no longer supported: 0.9.30||March 22nd, 2011||Windows, Mac OS X (Intel and PPC), Linux||Large number of new features, including docking and multiple source-code windows. Based on Free Pascal 2.4.2.|
|Old version, no longer supported: 0.9.30.2RC1||September 30th 2011||Windows, Mac OS X (Intel and PPC), Linux||Includes Free Pascal 2.4.4. Release candidate for Lazarus 0.9.30.2.|
|Old version, no longer supported: 0.9.30.2RC2||October 26th, 2011||Windows, Mac OS X (Intel and PPC), Linux||Release candidate for Lazarus 0.9.30.2.|
|Old version, no longer supported: 0.9.30.2||November 5th, 2011||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes.|
|Old version, no longer supported: 0.9.30.4RC1||March 3rd, 2012||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes, includes Free Pascal 2.6.0. Release candidate for Lazarus 0.9.30.4.|
|Old version, no longer supported: 0.9.30.4RC2||March 7th, 2012||Windows, Mac OS X (Intel and PPC), Linux||Release candidate for Lazarus 0.9.30.4.|
|Old version, no longer supported: 0.9.30.4RC3||March 11th, 2012||Windows, Mac OS X (Intel and PPC), Linux||Release candidate for Lazarus 0.9.30.4.|
|Old version, no longer supported: 0.9.30.4||March 14th, 2012||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes|
|Older version, yet still supported: 1.0RC1||July 29th, 2012||Windows, Mac OS X (Intel), Linux||Release candidate for Lazarus 1.0.|
|Older version, yet still supported: 1.0RC2||August 21st, 2012||Windows, Mac OS X (Intel and PPC), Linux||Release candidate for Lazarus 1.0.|
|Older version, yet still supported: 1.0||August 28th, 2012||Windows, Mac OS X (Intel and PPC), Linux||First final version. This stable release includes Free Pascal 2.6.0. Multiple corrections and improvements of the IDE, including a macro function, expanded code-folding and new debugger functions.|
|Older version, yet still supported: 1.0.2||October 10th, 2012||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes, minor additions to LCL and widgetsets|
|Older version, yet still supported: 1.0.4||December 2nd, 2012||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes, minor additions to IDE, LCL and widgetsets as well as LazReport and TAChart|
|Older version, yet still supported: 1.0.6||February 3rd, 2013||Windows, Mac OS X (Intel and PPC), Linux||Bug fixes, minor additions to IDE, LCL and widgetsets as well as LazReport and TAChart|
|Current stable version: 1.0.8||March 19th, 2013||Windows, Mac OS X (Intel and PPC), Linux||Bug fix release. Includes Free Pascal 2.6.2|
|Latest preview version of a future release: 1.1||N/A||N/A||in development|
|Future release: 1.2||N/A||N/A||planned|
Applications produced with Lazarus 
- ASuite is a free open source application launcher for Windows. From 2.0 Alpha 2, it's fully written in Lazarus/FPC.
- Cartes du Ciel is a free planetarium program for Linux, Mac OS X and Windows. The software maps out and labels most of the constellations, planets, and objects you can see with a telescope. It's fully written in Lazarus/FPC and released under GPL.
- Cheat Engine is an open source memory scanner/hex editor/debugger. It is useful for cheating in computer games. Since version 6.0 it is compiled with Lazarus/FPC.
- MyNotex is a free software for Gnu/Linux useful to take and to manage textual notes.
- Peazip is an open source archiver, made with Lazarus/FPC
- TorChat is moving away from Python, and is being rewritten in Lazarus + Free Pascal.
Libraries compatible with Lazarus 
- GLScene is a free OpenGL-based library that provides visual components and objects allowing description and rendering of 3D scenes.
- OpenWire is an Open Source library that allows pin type properties to make connections between LCL components similar to LabVIEW or Agilent VEE.
See also