Talk:GNU Lesser General Public License

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Does anyone know whether one can modify rendering of an LGPL portlet in... say an JSP page (from existing LGPL project) w/o having to release the whole thing. Also if one is providing a web-based service using LGPL code, specifically, modifying JSP pages - what implications does it have on the overall application as service? —Preceding unsigned comment added by (talk) 20:30, 11 December 2008 (UTC)

LGPL Inhertance[edit]

The article mentions that the LGPL contains no provisions for OO code, referencing an outdated FAQ relating to version 2.1 of the licence. However, the LGPL 3 contains the following phrase "Defining a subclass of a class defined by the Library is deemed a mode of using an interface provided by the Library." ( therefore implying that subclassing does not create a derivative work. This section of the article needs updating. Mallardtheduck 10:11, 29 October 2007 (UTC)

The claim "Inheritance creates derivative works in the same way as traditional linking" is true only in the vacuous sense. According to United States law, neither linking nor inheritance creates a derivative work. The statute 17 USC 101 defines

A “derivative work” is a work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted. A work consisting of editorial revisions, annotations, elaborations, or other modifications which, as a whole, represent an original work of authorship, is a “derivative work”.

The purpose of "derivative work" in US copyright law is to give the author of the derivative work copyright in the portions that he has created, when that work consists of an original work of authorship. Neither inheritance nor linking creates a derivative work in this sense, because no transformation of the original work through an original work of authorship has taken place.

Traditional linking (but not inheritance) creates what US law defines as a compilation.

A “collective work” is a work, such as a periodical issue, anthology, or encyclopedia, in which a number of contributions, constituting separate and independent works in themselves, are assembled into a collective whole.
A “compilation” is a work formed by the collection and assembling of preexisting materials or of data that are selected, coordinated, or arranged in such a way that the resulting work as a whole constitutes an original work of authorship. The term “compilation” includes collective works.

The reason the GPL can affect traditionally linked works in its "viral" aspect is that separate permission must be acquired from the copyright holder to include a work in a compilation (see 17 USC 201), so the GPL can grant linking permission only if the work as a whole is distributed under the GPL. But when there is no copying of [L]GPLed code into the resulting work, as is the case when there is dynamic linking or inheritance, the [L]GPL cannot affect the resulting work. —Preceding unsigned comment added by (talk) 15:05, 12 August 2009 (UTC)

Removed Fallacious Statement[edit]

the last line of the LGPL section, referring to code that has been returned to full GPL, said that it is "useful to prevent software from going commercial." This is repeating a myth and was removed. ref stallman on GPL 2000

Looks good. Belorn (talk) 14:24, 20 June 2012 (UTC)

Comment out[edit]

I commented this out: "Another major difference is that derivative works (which are not GPLed) must be software libraries." Where in the text of the license does it say that? Versions of created under the LGPL (I really doubt Ximian is using the SISSL!) aren't software libraries - David Gerard 20:08, 29 May 2004 (UTC)

  • Section 2. But this section only applies to derivative works that are "based on" the library, i.e. modifications, iterations, or evolutions of it. Derivative works such as programs that merely "use" the library are covered separately under Sections 5 and 6. -


There was one link for "What microsoft says about Software licenses". It's now removed. Is it not essential to know opinion of a propreitary company on FREE licenses?

I disagree. You can't present a balanced argument without hearing both points of view. I'm not employed by Microsoft and even I have reservations about the free software movement - somebody

has to feed the kids back home. Erichero 16:02, 26 October 2007 (UTC)

"The LGPL is now deprecated" - With what was it replaced?

It isn't deprecated, but should not be used for everything. The FSF commented on this because big projects like Wine and OpenOffice use this license when instead they should use the GPL. Dustin 16:03, 17 November 2006 (UTC)

About the "derivative work must be a software library":

2. You may modify your copy or copies of the Library or any portion of it, thus forming a work based on the Library, and copy and distribute such modifications or work under the terms of Section 1 above, provided that you also meet all of these conditions: a) The modified work must itself be a software library.

I have often wondered about Ximian OOo, which mentions the LGPL on the About box. It seems this might be an unenforced violation.

Regarding LGPL deprecation:

It was "replaced" by the GPL, even though the GPL predates the LGPL. Basically, Richard Stallman decided the LGPL wasn't such a good idea for a lot of what it was used for.

Jerickson314 20 April 2005

  • See the comments on "derivative works" above. Also, LGPL does not replace the GPL, it is an alternative to it. Which one to use is a matter of strategy. The GPL is preferred in many but not all cases. -
Jerickson314, read the article by Stallmann. His intention is for free software (Sourcecode) to proliferate. He can achieve this if as many people and developers use as much free software as possible. The talk about strategy boils down to this: If there exist many alternatives to a software "module" that a developer would use to create a closed application without requirements to open that application up, use LGPL for the free alternatives. That way, at least a part of the closed application (namely this module) remains source-open, because the developer has the incentive of using the free (as in beer) GNU library over the (probably not free) proprietary one.
However, for software modules / libraries / whatever where the free software is the superior choice, or maybe the only choice, the normal GPL should be used because use of the GPL would require the entire application to be open. The GPL considers even dynamic linking to be "deriverative", although this hasn't been tested in court.
I am not a lawyer, but that is the short version of how I understood Stallman. I hope it helps anybody. :) -- Nils Jeppe 06:58, 16 September 2006 (UTC)

Correction needed.[edit]

This feature is useful if one wants to create a version of the code that software companies cannot use in proprietary software products.

I believe this section is just plain wrong. The GPL can be used in "proprietary software" but the company must make the source code accessible to the public. Therefore, this section needs to be rewritten. --Mecanismo 13:35, 27 August 2005 (UTC)

  • This isn't the whole truth either. Providing the source code is only one of the options available; the basic requirement is that the program needs to be debuggable somehow. -

"Page 4" of the (Wikipedia) article is definitely wrong, though linked article states that

"the LGPL may be linked against non GPL-compatible software, even proprietary software, provided that the source of the LGPL part is made available, and that the LGPL part is upgradeable independently from the rest of the program linked against it."

which disagrees with user ""s post above.

An official page at says "the Library GPL permits use of the library in proprietary programs; using the ordinary GPL for a library makes it available only for free programs."

GPL compatibility[edit]

I removed this:

[About section 3, the GPL relicensing clause.] It is also necessary to ensure that the LGPL is "GPL-compatible", so that GPL-covered programs can use LGPL-covered libraries.

This is not true; the LGPL would allow a linked binary to be distributed under the GPL, so it is GPL-compatible. The clause is there to allow the reuse of code from LGPL libraries, in libraries or applications that are under the GPL. That is, straight reuse of code in the application, not linking.

Tim 21:30, 30 November 2006 (UTC)

Free to use for homepages?[edit]

Sorry, but no matter how hard I try and read the article (or the actual documents), I don't quite get whether or not it's allowed to use an image licensed with the GNU lesser general public license for, for example, a homepage? Mackan 12:16, 25 February 2007 (UTC)

Anybody? Please. Mackan 11:47, 27 February 2007 (UTC)
I think it would be allowed. You can always ask the image's copyright holder. —tedp 15:23, 12 May 2007 (UTC)
Use is always allowed, for any purpose. Chris Cunningham 15:58, 12 May 2007 (UTC)
What about certain forms of distribution? If I create a huge piece of software, and it includes a few LGPLed icons, can I distribute my software under a commercial, proprietary license? (talk) 05:27, 6 January 2008 (UTC)
Yes you can. One of the simplified explanations I have heard is that GPL is contagious, LGPL is not. The only time software using LGPL code has to be LGPL as well is if it is a derived work; that is, if you modify LGPL code, or cut-and-paste construct a new program based on LGPL code, then those modifications have to be licensed under the LGPL. In the case of your icon example, when you distribute it, the icons would have to be distributed in a form such that they could be replaced by the end-user with a more recent version of the icon. Basically, use of LGPL'd icons would be irrelevant to the rest of your project. As far as the intricacies of the license go, images are not a very good example to use, because there is not the same notion of "source code" as there is with a C program. Whenever you distribute an image, you are also distributing it's source code, so you are automatically complying with the provisions of the LGPL regardless of what is distributed along with it. Kinda long-winded, but hope that clears things up.-- (talk) 00:18, 5 March 2008 (UTC)
Images licensed under GPL or LGPL can be used on a home page; however, according to a strict reading of the GPL or LGPL, you would theoretically also have to distribute a copy of the GPL or LGPL license along with the image, or provide a link to the text of the GPL or LGPL; that is, according to the terms of the GPL/LGPL, distributing the image alone does not “automatically comply[] with the provisions of the LGPL” as claimed above, unless you also include the text of the license itself (or a link to it). Since this is often inconvenient and is often just a pain in practice, it is probably sufficient just to include a comment citing the source of the image and a caption such as “(licensed under <a href="{gpl,lgpl,fdl}.html">{GPL,LGPL,FDL}</a>).” Hope this helps. —Technion (talk) 16:16, 6 July 2010 (UTC)

This article in general is almost impossible for a layman to read and understand, a section of fair use examples would make this so much easier 23:41, 28 April 2007 (UTC)

The Licence it self?[edit]

I read the article and I don't understand what it means if piece of software is under this licence. As if am I allowed to use it? And what are the restrictions and constrains.--Cliff 21:56, 20 May 2007 (UTC)

You can use the software for any purpose. You can link it with binaries you distribute so long as you (a) impose no addition restrictions on use or redistribution of the LGPL code) and (b) include the license terms with the code you link to. If you actually modify any of the LGPL code, you must make your modifications available under the terms of the LGPL. Chris Cunningham 22:14, 20 May 2007 (UTC)
I added your statement to the article. Thanks a lot for that explanation, that's what I wanted to hear since I could understand so how exactly is this different from normal GPL and BSD.--Cliff 18:09, 28 May 2007 (UTC)
Note that the article (up till Dec 2015 - and beyond, since the top part is locked) contradicts the above in one place (yet the above from Thumperward IS correct.) The article (up till Dec 2015 and beyond) reads "it only guarantees the freedom of modification for components licensed under the LGPL, but not for any proprietary components." Actually, the truth is somewhat the reverse - modification of LGPL components IS restricted, but your added components are NOT - they free of any restriction or seizure by the LGPL terms. Specifically, you can't modify the LGPL code and keep those modifications private; but you can modify a program or OS etc by using your own components together with LGPL components and still keep those proprietary or secret or both. Whereas with GPL, if you add your own components to the Linux kernel and distribute that, say, The GPL now owns that code, too. Equally the LGPL guarantees you freedom to create using components licensed to you by others under any licenses whatsoever, without demanding the release of that code under GPL or LGPL. I was going to edit that in, but instead the error will remain, in the locked text. — Preceding unsigned comment added by (talk) 03:16, 11 December 2015 (UTC)

update to LGPLv3[edit]

This article needs an update, LGPLv3 has already been released since June 29, 2007. I'm not good enough at licences to edit it so could please anyone else do it ? Bertvandepoel 11:25, 4 August 2007 (UTC)

The FSF doesn't seem to have a page on the changes that were made in the LGPLv3. The text is vastly different and much shorter, but it doesn't seem to have any of the controversial provisions that the GPLv3 was all about. I'll see if I can find any sources discussing the changes. Nasarius 00:34, 9 November 2007 (UTC)
GPL v3 is raising a shitstorm. I don't quite understand it enough to write about it myself but I'm guessing it should be included. —Preceding unsigned comment added by (talk) 14:02, 28 November 2007 (UTC)
LGPLv3 is now just a patch for GPLv3, referring to it and stating the differences, because the difference is vastly shorter than the whole licence. --AVRS (talk) 14:38, 28 November 2007 (UTC)

Formatting complaints[edit]

Is it really necessary to bold the passages in the "Differences from the GPL" section? I find it a little pedantic and off-putting to the reader. Anyone opposed to removing the bold? --Ronocdh (talk) 03:51, 17 March 2009 (UTC)


? -- (talk) 01:57, 9 April 2009 (UTC)


So does this mean that lets say I use Pygame wich is licensed under (GNU Lesser General Public License), and make a game. does that mean the game must only be copyrighted under GNU Lesser General Public License or any other GNU license, or can it be placed under our own work or something? Gman124 talk 18:04, 2 September 2010 (UTC)

For information about GNU Lesser General Public License, please read about that article. Short answer: no, the resulting work do not need to be under the LGPL. Belorn (talk) 09:53, 23 January 2014 (UTC)

Was the difference between GPL and LGPL ever tested in court?[edit]

The LGPL purports to allow some situations which are prohibited by the GPL, but it is not clear that those situations are cases of infringement. Opinions on this vary. (This topic is covered in the GPL article from several angles.)

The question is, has this ever been challenged in a court case and what was the decision? Has there been a case revolving around the defendant using GPL-ed code as in a way that would fully conform to the LGPL, and what was the decision?

KazKylheku (talk) 18:46, 30 July 2014 (UTC)