Lazarus project files

Project directory structure

Typical directory structure for Lazarus project:

• created - auto-created by IDE or created manually
• VCS - need to be included in Version Control System

directory name	created	VCS	description
backup	auto	no	Contains backup copies of project source files.
lib	auto	no	Contains compiled binary files for different CPU and OS.
<Project name>.app	auto	no	macOS (Darwin) "application bundle" files (macOS treats folders with extension .app specially).
frames	manual	yes	TFrame descendant files (*.lfm, *.pas), recommended for large projects with many frames.
include	manual	yes	Platform-dependent includes. Contains sub-directories for different OS (darwin, linux, win32, win64, etc..) Recommended for multiplatform projects with platform-specific units.
languages	manual	yes	Contains *.po files with resource strings for different languages. Recommended for multi-language projects.
images	manual	yes	Picture files (*.png, *.jpg, *.ico, *.xpm, etc..), that can be compiled into resource by lazres utility. Recommended for projects and packages with many image files.
logs	manual	no	Debug output files (*.txt, *.log).

Project files extensions

The Lazarus Tutorial#The Lazarus files explains some extensions by an example.

• VCS - need to be included in Version Control System

extension	VCS	filetype	description
.lpi	yes	Lazarus Project Information	contains project-specific settings like compiler settings and needed packages. stored in XML
.lps	no	Lazarus Program Session	Personal data like cursor positions, source editor files, personal build modes. stored in XML
.lpr	yes	Lazarus Program	Pascal source of main program.
.lfm	yes	Lazarus Form	Form configuration information for all objects on a form (stored in a Lazarus-specific textual format, similar to Delphi dfm; the actions are described by Pascal source code in a corresponding *.pas file)
.pas	yes	Pascal code	Pascal code typically for a form stored in a corresponding *.lfm file
.pp .p	yes	Pascal code	Useful if you want to avoid confusion with Delphi source code files.
.inc	yes	Pascal code include	Included as part of Pascal code file. Typically contain platform-dependent definitions and routines.
.lrs	no	Lazarus Resource	Generated Lazarus Resource file; not to be confused with a Windows resource file. This file can be created with lazres tool (in directory Lazarus/Tools) using commandline: lazres myfile.lrs myfile.lfm
.compiled	no	FPC compilation state	Compiler does not generate any .compiled files. They are created by some build system (make, fpmake, lazbuild).
.ppu	no	Compiled unit	Compiled source code created by the Free Pascal compiler for each unit and program.
.o .or	no	Object file	Created by the compiler, every ppu file has a corresponding o file, needed by the linker.
.lpk	yes	Lazarus package information	package-specific settings, like compiler settings and needed packages; stored in XML
.lrt	no	Lazarus Resourcestring table	Lazarus Resourcestring table created when saving a lfm file and i18n is enabled. It contains the TTranslateString properties of the lfm. Do not edit them, they are overwritten.
.rst	no	Resourcestring table	Resourcestring table created by the compiler for every unit with a resourcestring section. Do not edit them, they are overwritten.
.rc	yes	Resource definition file	Delphi-compatible resource-definition script (.rc file) that describes the resources used by your application.
.po	yes	GNU gettext messages	When i18n is enabled the IDE creates/updated the .po files with the resourcestrings from the rst and lrt files.
.ico	yes	Icon file	Icon for application file
.res	yes/no	Binary resource	There are essentially 3 types in Delphi: 1) auto generated .res files. 2) other .res files for which you have source (.rc) and are declared with the RC file in project or source like {$R 'logo.res' 'logo.rc'}. 3) other .res files for which you don't have source. So category one shouldn't be in SVN (so essentially same as other pre-generated files like .dcu/.o or .ppu). Category two essentially also not, since they can be regenerated. Finally category 3, that should be kept. In older Delphi these were often files to e.g. enable themes while the Delphi version didn't know that windows version. This is less of a problem with Lazarus. You can also convert category 2 to 3 to simply including the .res (removing the .rc source), so that you don't have to add e.g. an image to SVN etc).

An example .gitignore file for Lazarus/Free Pascal

Lazarus.gitignore