Lazarus (software)

Lazarus is a free cross-platform visual integrated development environment (IDE) for rapid application development (RAD) using the Free Pascal compiler. Its goal is to provide an easy-to-use development environment for programmers developing with the Object Pascal language, which is as close as possible to Delphi.

Software developers use Lazarus to create native-code console and graphical user interface (GUI) applications for the desktop, and also for mobile devices, web applications, web services, visual components and function libraries for a number of different platforms, including Mac, Linux and Windows.

A project created by using Lazarus on one platform can be compiled on any other one which Free Pascal compiler supports. For desktop applications a single source can target macOS, Linux, and Windows, with little or no modification. An example is the Lazarus IDE itself, created from a single code base and available on all major platforms including the Raspberry Pi.

Features

Lazarus provides a highly visual development environment for the creation of rich user interfaces, application logic, and other supporting code artifacts, similar to Borland Delphi. Along with project management features, the Lazarus IDE also provides:
* A What You See Is What You Get (WYSIWYG) visual windows layout designer
* GUI widgets or visual components such as edit boxes, buttons, dialogs, menus, etc.
* Non-visual components for common behaviors such as persistence of application settings
* Data-connectivity components for MySQL, PostgreSQL, FireBird, Oracle, SQLite, Sybase, and others
* Data-aware widget set that allows the developer to see data in visual components in the designer to assist with development
* Interactive code debugger
* Code completion
* Code templates
* Syntax highlighting
* Context-sensitive help
* Text resource manager for internationalisation (internationalization)
* Automatic code formatting
* The ability to create custom components

Cross-platform development

Lazarus uses Free Pascal as its back-end compiler. Therefore, Lazarus can theoretically be used to develop applications for all platforms supported by Free Pascal.

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, it is possible to create applications in a ''write once, compile anywhere'' manner, unless system-dependent features are used explicitly.

Cross-compiling

As Free Pascal supports cross-compiling, Lazarus applications can be cross-compiled from Windows to Linux / macOS / etc. and vice versa.

Applications for embedded devices (smartphones, PDAs, routers, game consoles) can be cross-compiled from any desktop platform.

Lazarus Component Library

The standard application framework, Lazarus Component Library (LCL) was originally modeled after the Visual Component Library (VCL) in Delphi 6, but, unlike Delphi, is not restricted to Microsoft Windows operating systems. This is done by separating the definition of common widget classes and their widgetset-specific implementation. Each widget set is supported by providing an ''interface'' which interacts directly with the set.

Database development

Developers can install packages that allow Lazarus to support several database management systems (DBMSes). Programs can interact with DBMSes through code or by components dropped on a form.

The following DBMSes are supported out of the box:
* dBase and FoxPro, supported through th
TDbf component
* InterBase / Firebird. Se

* Microsoft SQL Server and Sybase ASE. Se

* MySQL and MariaDB. Se

* ODBC, ODBC databases. Se

* Oracle database, Oracle. Se

* PostgreSQL. Se

* SQLite. Se

* Simple, local, flat file databases through TBufDataset, TMemDataset and TSdfDataset.

Differences from Delphi

While resembling Embarcadero Delphi, Delphi in many ways, there are a few limitations regarding the performance and feature set, including:
* Under Windows, the default size of an executable file is larger than the Delphi 6 or 7 equivalent, as Lazarus stores debug information within the executable, rather than as separate files. From 0.9.30 onwards, Lazarus supports external debug symbols; program file size can be significantly reduced (via compiler options) by using an external symbols file. Alternatively, debug info can be stripped from EXEs (e.g. using a port of the UNIX strip command).
* Components for Delphi can be converted to work in Lazarus, which could be complex, but became less so since 0.9.30, based on FP 2.4.x.
* Lack of Datasnap (not a publicly documented system, Embarcadero proprietary enterprise functionality).
* Networking is mostly available.
* No support to directly call .NET libraries. Object Pascal code can be called from .NET software.
* No support for dynamically loadable packages.
* Not fully compatible with VCL. As mentioned previously, this is by design, although the 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 are a considerably bigger problem than incompatibilities between LCL and VCL.
* Microsoft Office connectivity limited to popping up Microsoft Excel with a simple table filled out (since FPC 2.6.0).
* Microsoft Component Object Model (COM) is supported (since Lazarus 2.2.0).

Distribution and licensing

Like Free Pascal, Lazarus is free software. Different portions are distributed under different free software licenses, including GPL, LGPL, MPL, and a modified version of LGPL.

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

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