Lazarus Packages: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		## Overview of the Lazarus Package System
2	2
3	3		For other meanings of Package in the combined FPC/Lazarus projects see [[packages(disambiguation)\|Packages(disambiguation)]].
4	4
5		-	~~<figure>~~
6		-	~~<img src="packagegraph1.png" title="packagegraph1.png" />~~
7		-	~~<figcaption>packagegraph1.png</figcaption>~~
8		-	~~</figure>~~
	5	+	![](/wiki-images/5/52/Packagegraph1.png)
9	6
10	7		## What is a Lazarus package?
11	8
12	9		A Lazarus package is a collection of units and components, containing information how they can be compiled and how they can be used by projects or other packages or the IDE. The IDE automatically compiles packages if some of its files are modified. In contrast to Delphi, packages are not limited to libraries and they can be OS independent. ([[packages\|Library Packages]] are specially compiled libraries used by applications, the IDE or both. Delphi/Library packages require in-compiler support, which FPC is not capable of at the moment and of course this magic is OS dependent.)
13	10
14	11		Currently the [[Free Pascal]] compiler only supports static packages, not dynamic packages. Therefore you must compile and restart the IDE, each time a package is installed or uninstalled.
15	12
16	13		A lazarus package is identified/distinguished by the name and its version.
17	14
18	15		Packages are ideal for sharing code between projects.
19	16
20	17		Here is a typical directory layout of a Lazarus package:
21	18
22	19		/home/user/pascal/pkg1/ - an arbitrary directory, often it is named similar to the package name
23	20		pkg1.lpk - the package file
24	21		pkg1.pas - this unit is automatically created by the IDE and is only needed for compiling
25	22		apackageunit.pas - your shared unit, choose a unique name that do not clash with other sources/packages
26	23		aform.pas - your shared form
27	24		aform.lfm - the form file of your shared form
28	25		lib/i386-linux/ - the output directory of the package. The directory and its content is automatically created.
29	26		pkg1.compiled - the state file containing the parameters how the package was compiled the last time.
30	27		pkg1.ppu
31	28		pkg1.o
32	29		apackageunit.ppu
33	30		apackageunit.o
34	31		aform.ppu
35	32		aform.o
36	33		aform.lfm
37	34
38	35		## Coming from Delphi
39	36
40	37		If you are familiar with Delphi packages then read the following paragraph, because there are some important differences between a Delphi and a Lazarus package.
41	38
42	39		- Lazarus packages are not only a dynamic library. They are used to share units between projects and modularize big projects.
43	40		- Sometimes the Delphi main file of a package is called "Package Project". This term makes no sense under Lazarus.
44	41		- Many Delphi packages provide one "package project" per compiler version. This is hardly needed under Lazarus. But you can do that for Delphi compatibility. Lazarus packages have version information and projects can define that they require at least or at most a specific version of a package. Lazarus will automatically load the right version.
45	42		- If a unit can not be found, under Delphi you are used to add the directory to the global search path. This has many drawbacks when sharing code. That's why this is not supported by Lazarus. Use packages instead.
46	43
47	44		## FAQ
48	45
49	46		Q: Do I need to install a package?\
50	47		A: You only need to install a package, if it contains designtime items, like components for the IDE component palette. If you don't use those items, you don't need to install the package. If you only want to use a package in your project, don't install it. Use the project inspector and add a requirement.
51	48
52	49		Q: I installed a package, but the IDE does not find the units\
53	50		A: Installing a package means that the package is integrated into the IDE, not in your project. These are separate things. To use a package in your project, use Project -\> Project Inspector -\> Add -\> New Requirement. And uninstall the package, if it does not contain any IDE goodies.
54	51
55	52		## Quick Start
56	53
57	54		To see the packagesystem in action and to get used to it, do the following:
58	55
59	56		### Creating a new package
60	57
61	58		- Package-\>New Package... or File-\>New... -\> Package -\> Package
62	59		- A package editor opens
63	60
64		-	~~<figure>~~
65		-	~~<img src="How_to_write_lazarus_component_package_maker.png" title="Package Maker" />~~
66		-	~~<figcaption>Package Maker</figcaption>~~
67		-	~~</figure>~~
	61	+	![](/wiki-images/3/37/How_to_write_lazarus_component_package_maker.png)
68	62
69	63		- A window titled "Save Package NewPackage 0.0(.lpk)" opens. Choose a directory and a name for your new package. The name must be a valid Pascal identifier with the extension .lpk*.
70	64		- Use the Save button at the bottom right to save the package in the directory and name you've chosen.
71	65		- Depending on your 'naming' setting in the 'environment options', the IDE will ask you to save the file lowercase. Say yes.
72	66
73	67		Congratulations: You have just created your first package!
74	68
75	69		### Adding a new component
76	70
77	71		- Use the Add button -\> New component
78	72		- Choose a component in the ancestor type combobox. For instance: TBevel.
79	73		- Click Ok
80	74		- The file will be added to the package and opened in the editor
81	75		- Install the package by clicking the 'install' button in the top of the package editor.
82	76		- Lazarus will save the package and ask you, if the IDE should be rebuilt. Say yes.
83	77		- The packages are statically linked, so a restart of the IDE is needed.
84	78		- Restart Lazarus and see your new component in the component palette (For example: A TBevel1 will be on the 'Additional' page).
85	79		- If you do not see your new component in the component palette, it is most likely that you are not running the re-compiled version of Lazarus. You can set where Lazarus builds to in: Tools -\> Options -\> Environment options -\> Files -\> Lazarus directory. Instead of calling lazarus directly, you also can use [[startlazarus]], which starts the newly created lazarus, for example the lazarus executable in the ~/.lazarus directory, if you don't have write access to the directory lazarus was installed into.
86	80
87	81		Congratulations: You have just installed your first package with your first package component.
88	82
89	83		### Add a component icon
90	84
91	85		Component icons can use Lazarus resources or FPC resources.
92	86
93	87		#### Using Lazarus resources
94	88
95	89		Also page exists here: [[How to add icons my package components]].
96	90
97	91		The idea is to create a png, convert that into a lrs include file using the [[lazres]] tool and include that. Since 0.9.29 there is a button on the new component page to do that automatically.
98	92
99	93		Here are the details:
100	94
101	95		- Size of PNG file should be 24x24
102	96		- Name of png must be the class name of the new component, case does not matter (e.g. tmyComponent.png for TMyComponent).
103	97
104	98		To create the lrs file run (where TMyComponent is the class name of your component and yourunit is the unit name):
105	99
106	100		`~/lazarus/tools/lazres yourunit.lrs TMyComponent.png`
107	101
108	102		- You may need to compile lazres at first use. Simply open the lazres.lpi in the IDE and at the menu click run \> build.
109	103
110	104		Hint: You can add more than one image to the lrs file by appending the image filename at the end. For example
111	105
112	106		`~/lazarus/tools/lazres yourunit.lrs TMyComponent.png TMyOtherCom.png ...`
113	107
114	108		Following is a sample of the resulting yourunit.lrs file.
115	109
116	110		``` pascal
117	111		LazarusResources.Add('TMyComponent','PNG',[
118	112		#137'PNG'#13#10#26#10#0#0#0#13'IHDR'#0#0#0#24#0#0#0#24#8#2#0#0#0'o'#21#170#175
119	113		+#0#0#0#4'gAMA'#0#0#177#143#11#252'a'#5#0#0#0'\|IDAT8O'#237#212#209#10#192' '#8
120	114		+#5'P'#247#231#251's'#215#138#133#164#166'\'#220#195'`'#209'c'#157'L'#173#131
121	115		+#153#169'd4'#168'dP'#137'r_'#235'5'#136'@Zmk'#16'd9'#144#176#232#164'1'#247
122	116		+'I'#8#160'IL'#206'C'#179#144#12#199#140'.'#134#244#141'~'#168#247#209'S~;'#29
123	117		+'V+'#196#201'^'#10#15#150'?'#255#18#227#206'NZ>42'#181#159#226#144#15'@'#201
124	118		+#148#168'e'#224'7f<@4'#130'u_YD'#23#213#131#134'Q]'#158#188#135#0#0#0#0'IEND'
125	119		+#174'B`'#130
126	120		]);
127	121		```
128	122
129	123		- Click the Add button again, goto the Add File tab and browse to the yourunit.lrs file and click Ok. This is needed, so that the IDE checks this file for changes and will recompile your package.
130	124
131	125		- Add an include directive to yourunit:
132	126
133	127		``` pascal
134	128		unit YourUnit;
135	129		...
136	130		uses
137	131		..., LResources;
138	132		...
139	133		implementation
140	134		...
141	135		initialization
142	136		{$I yourunit.lrs}
143	137		end.
144	138		```
145	139
146	140		Note: You can include more than one lrs file, but each only once.
147	141
148	142		- That's all. Compile or install your package
149	143
150	144		#### Using FPC resources
151	145
152	146		Create a 24x24 16 color bitmap for each component. This format won't support PNG files. Then create an rc file as follows:
153	147
154	148		`TMYCOMPONENT1NAME BITMAP "pathtobitmap1//bitmap1.bmp"`\
155	149		`TMYCOMPONENT2NAME BITMAP "pathtobitmap2//bitmap2.bmp"`\
156	150		`....`\
157	151		`TMYCOMPONENTnNAME BITMAP "pathtobitmapn//bitmapn.bmp"`
158	152
159	153		Note that double slashes (Linux) and double backslashes (Windows) are used in the bitmap path. It is advisable for the file's name to be the same as the package name with an extension of rc, ie MyPackageName.rc
160	154
161	155		Let windres (Binutils) create the actual resource:
162	156
163	157		`pathToWindres/windres -J rc -O res "MyPackageName.rc" "MyPackageName.dcr"`
164	158
165	159		Alternatively, you can use the lazres tool to create a .res file:
166	160
167	161		`pathToLazarus/tools/lazres MyPackageName.res bitmap.bmp bitmap_150.bmp bitmap_200.bmp`
168	162
169	163		Add to the registration unit of the package {\$R .dcr} or {\$R .res} right after the implementation keyword, and compile/install the package.
170	164
171	165		### Creating a package for your common units
172	166
173	167		Let's say you have some units, that you want to use in your projects. Put the units in a separate directory, for instance C:\MySharedUnits.
174	168
175	169		- Package-\>New Package or File-\>New... -\> Package -\> Standard Package
176	170		- A package editor opens
177	171		- Use the Save button at top left. Choose C:\MySharedUnits\MySharedUnits.lpk. The package name must not conflict with any existing unit.
178	172		- Depending on your 'naming' setting in the 'environment options', the IDE will ask you to save the file lowercase. Say yes.
179	173		- Now you have a package with the name MySharedUnits stored as C:\MySharedUnits\mysharedunits.lpk.
180	174		- Adding the units: Add-\>Add Files-\>Add directory.
181	175		- A dialog will appear with the directory C:\MySharedUnits and some include and exclude filters. Click Ok to add all units.
182	176		- The units will now be listed. Click Add files to package.
183	177		- The files are now added to the package. Click Save.
184	178		- If your units only require the standard FPC units you can now simply press Compile. Otherwise see below.
185	179
186	180		### Adding the LCL as dependency
187	181
188	182		If your package contains forms or any other GUI LCL unit, then it requires the LCL package.
189	183
190	184		- In the package editor of your package click Add -\> New Requirement
191	185		- Choose as package name LCL
192	186		- Click Ok.
193	187		- The LCL is now added under Required Packages. Click Save.
194	188
195	189		You can see the what the LCL does, by clicking in the package editor of your package Compiler Options / Inherited.
196	190
197	191		If you only use non-GUI LCL components such as [[fileutil]], you can add a dependency to LCLBase
198	192
199	193		### Use your package in your project
200	194
201	195		You need to add a dependency from the project to your new package. There are several ways to do this:
202	196
203	197		- Open your package. For example via Package / Open recent package. On the package editor of your package click More ... / Add to project.
204	198		- Or you can use the project inspector:
205	199		- Project / Project Inspector.
206	200		- Click on the Add button with the plus.
207	201		- Select the page New Requirement
208	202		- Choose as package name your package
209	203		- Click Ok
210	204
211	205		## The IDE menu items for packages
212	206
213	207		- Package -\> New Package or File-\>New... -\> Package -\> Standard Package
214	208		- Creates a new package.
215	209		- Project -\> Project Inspector
216	210		- Here you can see, what packages are required by the currently open project.
217	211		- You can add new dependencies and remove unneeded ones.
218	212		- Run -\> Compiler options -\> Inherited
219	213		- Here you can see what compiler options are inherited from which package.
220	214		- Package
221	215		- Open package: A dialog shows all open packages with their state.
222	216		- Open package file: Open a .lpk file
223	217		- Open package of current unit: Open the .lpk file, that belongs to the file in the source editor
224	218		- Open recent package: Open a recently open package file (lpk file)
225	219		- Add active unit to a package: Adds the unit in the source editor to a package
226	220		- Package Graph: The package graph shows all open packages and their dependencies.
227	221		- Configure installed packages: Edit the list of packages installed in the IDE. Install or uninstall several packages at once.
228	222
229	223		### Removing Packages
230	224
231	225		- To remove installed components, on the IDE menu, click Package \> Configure installed packages. The following image shows the Installed Packages tool.
232	226
233		-	~~<figure>~~
234		-	~~<img src="How_to_write_lazarus_component_installed_components.png" title="Installed Components" />~~
235		-	~~<figcaption>Installed Components</figcaption>~~
236		-	~~</figure>~~
	227	+	![](/wiki-images/0/0e/How_to_write_lazarus_component_installed_components.png)
237	228
238	229		- Select the package you want to uninstall and click Uninstall selection.
239	230
240	231		If something goes wrong with a package (for instance a package directory is deleted without first uninstalling it), Lazarus may not allow you to uninstall packages. To fix the problem, at the IDE menu click Tools \> Build Lazarus. Lazarus will rebuild all packages and restart. You should now be able to uninstall problematic packages.
241	232
242	233		## The theory
243	234
244	235		Each Lazarus package has a .lpk file. A package is identified by its name and its version. The name must correspond to the lpk filename. For example:
245	236
246	237		Name: Package1, Version: 1.0, Filename: /home/.../package1.lpk.
247	238
248	239		- The IDE automatically creates the main source file (package1.pas). See below. The lpk file contains information about the required packages, the files it uses, how to compile them, and what is needed to use the package by other packages/projects. The directory where the lpk file is, is called the "package directory".
249	240		- The IDE maintains a list of all package files (\<config directory\>/packagelinks.xml). Every time a package is opened in the IDE it will be added to this list. When a package is opened, the IDE automatically opens all required packages via this list.
250	241		- Normally a package has a source directory with some pascal units. And normally the lpk file will be there too. A package has also an output directory. Default is the subdirectory 'lib/\$(TargetCPU)-\$(TargetOS)/' in the package directory.
251	242		- Before a package is compiled the IDE checks all required packages and if they need update and have the auto update flag, they are compiled first. Then the IDE creates the package main source file. If the lpk file was package1.lpk, then the main source file is package1.pas. This file contains all units in the uses section plus a [[Register (package)\|'Register' procedure]], which is called in the initialization section.
252	243
253	244		For example:
254	245
255	246		``` pascal
256	247		{ This file was automatically created by Lazarus. Do not edit!
257	248		This source is only used to compile and install
258	249		the package GTKOpenGL 1.0.
259	250		}
260	251		unit GTKOpenGL;
261	252
262	253		interface
263	254
264	255		uses GTKGLArea, GTKGLArea_Int, NVGL, NVGLX, LazarusPackageIntf;
265	256
266	257		implementation
267	258
268	259		procedure Register;
269	260		begin
270	261		RegisterUnit('GTKGLArea', @GTKGLArea.Register);
271	262		end;
272	263
273	264		initialization
274	265		RegisterPackage('GTKOpenGL', @Register);
275	266		end.
276	267		```
277	268
278	269		- Then the compiler is called and the package is compiled to the output directory.
279	270		- The IDE compares the current compiler options with the last one, which are stored in the .compiled file. If they differ the IDE cleans up the output directory and compiles the package with -B, telling the compiler to recompile everything it can. Differences in search paths and verbosity options do not trigger a clean up. Since 0.9.31 the IDE removes all files in the unit output directory on clean up if the output directory does not contain source files (listed in the package editor) and is not shared with required packages.
280	271		- After compilation (successful or not) the state file is created. The state file is put into the output directory. It has the name \<packagename\>.compiled and contains the information, how the package was compiled and if the compilation succeeded. This state file is used by the IDE to check if update is needed and if a full recompile (-B) is needed.
281	272
282	273		For example: gtkopengl.compiled:
283	274
284	275		``` xml
285	276		<?xml version="1.0"?>
286	277		<CONFIG>
287	278		<Compiler Value="/usr/bin/ppc386" Date="781388725"/>
288	279		<Params Value=" -Rintel -S2cgi -CD -Ch8000000 -OG1p1
289	280		-Tlinux -gl -vewnhi -l -Fu../../../lcl/units
290	281		-Fu../../../lcl/units/gtk -Fu../../../packager/units
291	282		-Fu. -FElib/ gtkopengl.pas"/>
292	283		</CONFIG>
293	284		```
294	285
295	286		- The IDE opens all needed packages automatically. This means, it opens all installed packages, all packages marked for installation (auto install), all packages with an open Editor, all packages required by the project and all packages required by one of the other packages. Unneeded packages are automatically unloaded, when the IDE becomes idle.
296	287		- The IDE never opens two packages with the same name at the same time. When the user opens another package file with the same name the IDE will ask if it should replace the old one.
297	288		- The IDE maintains two extra sets of packages: The 'installed' packages and the 'auto install' packages. The auto install packages will be linked into the IDE on next compile. It creates two new files in the config directory: staticpackages.inc and idemake.cfg. Then it calls 'make ide OPT=@/path/to/your/config/idemake.cfg' to compile itself.
298	289
299	290		## Package states
300	291
301	292		A package can have none, one or several of the following states:
302	293
303	294		- used - a package can be used by a project or package, i.e. it is required and listed in Project inspector or Package Editor respectively. When you open a project or package all used packages are automatically loaded by the IDE.
304	295		- loaded - When the IDE opens a .lpk file the package is loaded. The IDE knows its settings and files. The IDE automatically loads all used packages of a project and its installed packages. This does not load the package code, as the compiler and IDE do not support dynamic packages yet.
305	296		- marked for installation - To run the package code inside the IDE, you need to rebuild the IDE and restart it. That means the first step is to mark the package for installation. Then rebuild the IDE and finally restart it.
306	297		- installed - The compiled code of the package is loaded and registered in the currently running IDE. If the IDE was able to locate the .lpk file it will be loaded.
307	298		- uninstall on next start - The package is installed, but will not be compiled into a new IDE. That means, when you rebuild the IDE and restart it, the package will no longer be installed. Keep in mind, that a package can be required indirectly by an installed package and thus will be installed as well.
308	299
309	300		## Hints and Tips
310	301
311	302		Please add any hints, tips or gotchas here.
312	303
313	304		- To rename a package, use 'save as'.
314	305		- You can add to every dependency the default filename. For instance you provide an example project for your package. When another programmer opens your example for the first time, the IDE does not know where the lpk file is. Simply right click on the dependency in the project inspector and 'Store file name as default for this dependency'. The file name is stored relative to the project. You can do the same for package dependencies.
315	306		- Use package: to use all units of the package in the project, enable the Add package unit to uses section on package editor / Options / Usage. When the package is added to a project, the lpr uses section is extended with the package main unit. For example if the package implements a new graphic type, it only has initialization sections, but the no project code use it directly.
316	307
317	308		## Adding existing components to a Package
318	309
319	310		If you want to add a file that contains a component to an existing package, you can do the following:
320	311
321	312		- Open the package file
322	313		- Click on the 'Add' file to add a new item to the package.
323	314		- Select the unit tab in the 'Add to package' dialog.
324	315		- Choose the file to add.
325	316		- Check the 'Has register procedure' if the unit contains a Register procedure. If you do not do this, the component(s) will not be shown on the component palette.
326	317		- Click 'Add unit'.
327	318		- Recompile and install the package.
328	319
329	320		That's it. The component should now show on the component palette.
330	321
331	322		## Create a package with a unit that has the same name as the package
332	323
333	324		Normally the IDE auto creates the registration code into a unit with the same name as the package. If you want to name your package the same as an existing unit, for example because the package has only one unit, then you need at least Lazarus 0.9.29 and use this:
334	325
335	326		- Make a backup of your unit mypackage.pas.
336	327		- Create the package mypackage.lpk normally and do not add the unit yet.
337	328		- Add a new unit, for example mypackageall.pas.
338	329		- Select the unit mypackageall.pas in the package editor and right click for the popup menu.
339	330		- Change File type to Main Unit.
340	331		- Now restore your unit mypackage.pas and add it to the package.
341	332
342	333		## File Type
343	334
344	335		Select a file in the package editor, right click for the popup menu. File Type:
345	336
346	337		- Unit - A .pas or .pp file (or .p in mode macpas)
347	338		- Virtual Unit - Placeholder for a unit not in the package folders. For example the package FCL contains some virtual units for some FPC units.
348	339		- Main Unit - this unit contains the autogenerated code to compile the package. There can only be one per package.
349	340		- Issues xml file [[IDE Window: Restriction Browser\|see here]]
350	341
351	342		## The Register procedure
352	343
353	344		To show a component on the component palette, it must be registered in Lazarus. This is done in the 'Register' procedure. This is a procedure that must appear in the interface section of the unit it is in, and must issue one or more RegisterComponent calls, as well as install property and component editors for the components.
354	345
355	346		One or more Register procedures can be present in a package: in the package editor, you must indicate the units that have a 'register' procedure, so Lazarus knows which procedures it must call when the package is installed.
356	347
357	348		There are 2 ways to mark a unit as having a register procedure:
358	349
359	350		- You can do this while adding the units to the package (see the 'Adding existing components to a package' section),
360	351		- or you can select the unit in the package dialog, and set the 'Register' checkbox in the details panel.
361	352
362	353		Do not forget to recompile and install the package after changing the properties.
363	354
364	355		## Search paths
365	356
366	357		All search paths are stored relative to the directory of the .lpk file. If you use an absolute path you have either not understood packages or you don't care.
367	358
368	359		Each package has two types of search paths:
369	360
370	361		- Paths in the Options / Compiler Options are used to compile the package itself.
371	362		- Paths in the [[IDE Window: Package Options\|Options / Package Options / Usage]] are used by packages and projects that require this package. In other words these paths are added to the search paths of the project (or requiring package). Keep in mind that if project uses package A and that uses package B, the Usage options of B are appended to A and the project.
372	363
373	364		Since 0.9.29 you can specify compiler options depending on the target platform.
374	365
375	366		## Your package provides a library, how to extend the linker search path in all your projects
376	367
377	368		A package can define search paths that are added to packages and projects using it. See [[IDE Window: Package Options\|Options / Package Options / Usage]].
378	369
379	370		## Design Time vs Run Time package
380	371
381	372		There are four different types of packages.
382	373
383	374		1. A design and runtime package can be installed in the IDE and can be used normally by projects. This is the default.
384	375		2. A design time package can be installed in the IDE and provides IDE extensions like new components, new file or project types, new menu items, new component or property editors, etc. Projects can use design time packages (i.e. they are listed in the project inspector requirements), but by default a design time package is not compiled into the project. That means project units cannot use units of the design time package. When a project uses such a package the IDE warns before opening a form of the project, so the user can install it first. To test a design time package outside the IDE you may want to use it in a test project. For this case you can change this in Project Options / Miscellaneous / Use design time packages.
385	376		3. A run time package can be used by projects. A user cannot install such a package directly (it is not listed). It cannot register things in the IDE. It can be used by design time packages, so it can be installed indirectly.
386	377		4. A run time only package can only be used by projects. It cannot be installed in the IDE, not even indirectly. For example if the package is incompatible with the core IDE packages like the LCL. Since 0.9.31.
387	378
388	379		### Typical scenario for a run time and design time package
389	380
390	381		You have a component library called Awesome and you want to write some IDE editors for some special properties. For example a property editor for the property Datafile which shows a TOpenDialog to let the user select a file. You can put the components into one run time package named AwesomeLaz.lpk' and create another directory design for the design time package AwesomeIDELaz.lpk. Move all units containing the IDE editors and registering stuff into the design directory. Add a dependency in AwesomeIDELaz to AwesomeLaz. Make sure they do not share units or search paths. For an example see components/turbopower_ipro/: The run time package is turbopoweripro.lpk and the design time package is design/turbopoweriprodsgn.lpk.
391	382
392	383		### For Delphians: I can not install a run time package, why not?
393	384
394	385		Installing a package means compiling the whole code into the IDE. A run time package does not contain code for the IDE or maybe even bites it. In order to use a package in your project, simply open the package, right click on the package editor for the popup menu and click Add to project. Alternatively you can use View / Project Inspector. The project inspector shows what packages are used by your project, you can add dependencies or delete them.
395	386
396	387		### Examples
397	388
398	389		Example for extending the Usage / Units path.
399	390
400	391		The tiOPF framework has the following directory layout, due to the fact that it compiles for FPC, Delphi 5-7, D2005 and D2006:
401	392
402	393		Source <= full path \Programming\3rdParty\tiOPF\Source
403	394		\Compilers
404	395		\Delphi7 <= Delphi 7 package files live here
405	396		\D2005
406	397		\FPC <= the tiOPF.lpk lived here
407	398		\Core <= core unit files
408	399		\Options <= optional unit file for extra features
409	400		\GUI
410	401
411	402		Using this example, the following paths are included in the "Options - Usage - Units" editbox:
412	403
413	404		`"$(PkgOutDir);..\..\Core;..\..\Options;..\..\GUI" `
414	405
415	406		This search path will be added to whatever project uses this package. The default is \$(PkgOutDir), which would add only the ppu files to the project. Adding more search paths has the effect that the .pas source files are found by the compiler a second time - once when compiling the package and once when compiling your project. Since package and project use different settings the compiler might create a second version of the ppu, which is put into your project's output directory. Then you have two ppu for one unit and then you can get strange errors. To avoid the duplication disable the compilation of the package, by setting it to compile only manually.
416	407
417	408		## Platform specific units
418	409
419	410		There are various ways to deal with separating platform-specific code:
420	411
421	412		### One unit per platform, several units with same name
422	413
423	414		For example the unit myconnect.pas has two versions, one for Windows and one for Unix/Linux/macOS/BSD. The idea is to put the units into different sub directories and use macros in search paths.
424	415
425	416		- Create two sub directories: win and unix.
426	417		- Add to the package options / Compiler options / Paths / Other unit files the path \$(SrcOS). SrcOS is a [[IDE Macros in paths and filenames\|macro]], that translates to win under Windows and unix under Linux/macOS/BSD.
427	418		- Create a new package unit (package / Add / New file / Pascal unit) and save it under win/myconnect.pas.
428	419		- If the unit is not selected in the package editor, select it.
429	420		- Disable use unit.
430	421		- Create a second package unit (package / Add / New file / Pascal unit) and save it under unix/myconnect.pas.
431	422		- Keep the use unit enabled. It should be used once.
432	423
433	424		### One unit for only one platform / conditional unit
434	425
435	426		For example: the unit mywin.pas should only be used under Windows, i.e. it should only be used and compiled if the flag Windows is defined.
436	427
437	428		The idea is to use the unit indirectly using IFDEFs. The following example shows how the unit mywin.pas is only used and compiled when the flag Windows is defined.
438	429
439	430		- Create a new package unit (package / Add / New file / Pascal unit) and save it under mywin.pas.
440	431		- If the unit is not selected in the package editor, select it.
441	432		- Disable use unit.
442	433		- Create a new package unit (package / Add / New file / Pascal unit) and save it under mypkgcompile.pas.
443	434		- Add to the uses section of mypkgcompile.pas:
444	435
445	436		``` pascal
446	437		uses
447	438		Classes
448	439		{$IFDEF Windows}
449	440		,mywin
450	441		{$ENDIF}
451	442		;
452	443		```
453	444
454	445		Note: mypkgcompile will be compiled under all platforms. mywin will only be compiled under Windows. You don't need to use the unit mypkgcompile in your project.
455	446
456	447		## Different versions of a package
457	448
458	449		If you work with different versions of a package, you can open at any time the other package file. The old package will be closed and the new one will be opened. Registered items will be transferred to the new package. For example the component palette still shows the components of the old package, with which the IDE was built. But right clicking on a component will show a menu item to open the recently used package.
459	450
460	451		You can specify the minimum, maximum version required. When the project is opened and there are multiple .lpk files the IDE will automatically open the one with the right version.
461	452
462	453		If you work with different projects that require different versions of a package (for example with different branches of the same package), you can define the preferred one in the dependencies. In the project inspector right click on the dependency and click on Set file name as preferred for this dependency. When the project is opened, the preferred package will be opened. If there is already a package with the same name it will be replaced. This feature exists since 0.9.29.
463	454
464		-	~~<figure>~~
465		-	~~<img src="SetDefaultPkDependency1.png" title="SetDefaultPkDependency1.png" />~~
466		-	~~<figcaption>SetDefaultPkDependency1.png</figcaption>~~
467		-	~~</figure>~~
	455	+	![](/wiki-images/c/c8/SetDefaultPkDependency1.png)
468	456
469	457		[[IDE Window: Project Inspector\|Project Inspector]]
470	458
471	459		### Example library with multiple lpk
472	460
473	461		A library has two lpk files, main.lpk and sub.lpk. main depends on sub. The library has two version 1.0 and 2.0.
474	462
475	463		trunk/
476	464		main.lpk version 2.0, requires sub
477	465		sub.lpk version 2.0
478	466		fixes/
479	467		main.lpk version 1.0, requires sub
480	468		sub.lpk version 1.0
481	469
482	470		When you open main.lpk 1.0 for the first time, the IDE searches the package sub in its database and then it searches sub.lpk in the current folder. It finds sub.lpk 1.0 and loads it.
483	471
484	472		When you then open main.lpk 2.0, the IDE knows already a sub.lpk, the version 1.0 and loads it. It does not load the sub.lpk 2.0.
485	473
486	474		There are two solutions:
487	475
488	476		#### Using minimum, maximum version
489	477
490	478		You can set for each dependency the minimum and maximum version. When you set the minimum and maximum version of the dependency the following will happen: The main 1.0 and sub 1.0 is open. You open main 2.0 which requires sub \>=2.0 and \<=2.0. The IDE unloads main 1.0, loads main 2.0. The sub 1.0 does not fit, so the IDE searches for sub 2.0. Again it first searches in its database and then in the current folder. It finds sub.lpk and loads sub 2.0.
491	479
492	480		#### Using preferred file name
493	481
494	482		If the two lpk files are always distributed together you can use instead of minimum and maximum versions the preferred option. Open from trunk the main.lpk and sub.lpk to make sure that the right versions are loaded. Then right click on the dependency from main to sub and choose preferred file name. The file name will appear to the right of the dependency. Repeat this step with the lpk files from version 2.0. The IDE will now always open the right sub.lpk.
495	483
496	484		## Build modes
497	485
498	486		You can add build modes to your package. See here for the various ways to achieve this:
499	487
500	488		[[Macros and Conditionals\|Build modes for packages]]
501	489
502	490		## Compiling a package via make
503	491
504	492		The IDE can create a simple Makefile for a package via Package editor / More ... / Create Makefile. The IDE creates the file Makefile.fpc and calls fpcmake, which creates the Makefile. Since 0.9.29 the IDE also creates the file Makefile.compiled. If you are using a version control system like svn or git, add all three files to the repository:
505	493
506	494		`Makefile`\
507	495		`Makefile.fpc`\
508	496		`Makefile.compiled`
509	497
510	498		You can now run make (e.g. open a console, cd to the package directory with the Makefile) to compile the package. This will compile the package and after successful compilation copy the Makefile.compiled to the unit output directory.
511	499
512	500		Notes:
513	501
514	502		- The Makefile uses fixed paths, so it will not automatically adapt to changes as the IDE or lazbuild.
515	503		- The IDE can recreate the Makefile on every compile. Enable the option Package editor / Options / Compiler Options / Compilation / Create Makefile.
516	504		- The Makefile does not contain the logic for conditionals and build macros, it contains the settings at the time of creation.
517	505		- The macros \$(TargetOS), \$(TargetCPU) and \$(LCLWidgetType) are replaced by %TargetOS%, %TargetCPU% and %LCLPlatform%. The Makefile has somelogic to set some default values. You can override them (e.g. make LCLPlatform=qt).
518	506		- The Makefile.compiled file is copied by the Makefile after successful compilation to \<PkgOutDir\>/\<PkgName\>.compiled and is checked by the IDE (and lazbuild) if a package needs a recompile. For example the Lazarus binaries (Windows Installer, deb and rpm packages, OS X dmg package) are compiled via make and when the IDE is started and compiles a program it will not recompile used packages, unless the user set some extra flags. For example when the user changes the IDEBuildOptions via the Configure Build Lazarus dialog the IDE will detect the difference and recompile the package on next compile.
519	507		- If you forget to add the Makefile.compiled to svn you will get on make the error: /bin/cp: cannot stat \`Makefile.compiled': No such file or directory
520	508
521	509		## Creating a closed sourced package
522	510
523	511		Goal: you want to publish a package, but you want to keep the source closed.
524	512
525	513		At the moment many IDE functions require the source; the IDE warns if the source of a unit is missing. Therefore you must publish the interface parts of the units, and the files the compiler creates (ppu and o files).
526	514
527	515		Steps:
528	516
529	517		- Create a copy of the package folder and change this copy as follows.
530	518		- In the package editor / Options / IDE integration, set Update / Rebuild to Manual compilation.
531	519		- Compile it once.
532	520		- Delete the implementation sections of all units (i.e. everything after the implementation keyword of each unit including the initialization and finalization, only keeping the "end."). You can also remove the private section.
533	521		- Optional: You can use the publish package tool (Package Editor / More... / Publish Package) to create a zip of the package.
534	522		- You can delete the .compiled file, Makefile, rst files, lrt files. All other files in the output directory like .ppu, .o, .lfm files are needed by the compiler. The IDE needs the .lpk and the stripped .pas and .inc files.
535	523
536	524		There is a command line utility sourcecloser which alters the lpk and removes implementation sections. You can find it under lazarus/components/codetools/examples/sourcecloser.lpi.
537	525
538	526		See also:
539	527
540	528		- this article about FPC closed source units: [[Releasing units without source code]]
541	529		- Prezi: <http://prezi.com/vpuyxca-qboq/how-to-create-a-closed-source-package-with-lazarus/>
542	530
543	531		## Parallel Compilation
544	532
545	533		The IDE and lazbuild compile packages in parallel (since 1.3). Each package is still compiled with one call of fpc (single threaded).
546	534
547	535		You can set the maximum number of parallel processes in Tools / Options / Messages Window. By default it tries to guess the amount of cpu cores with the function GetSystemThreadCount in unit UTF8Process.
548	536
549	537		## See also
550	538
551	539		- [[How To Write Lazarus Component]] - a tutorial about creating a new component.
552	540		- [[Install IDE packages without the IDE]]
553	541
554	542		---
555	543		From the Free Pascal wiki, page "Lazarus Packages", as it stood on 2023-12-13 after a change by Coz, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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