Editing Q Public License

{{Short description|Software license}}
{{Redirect|QPL|the library system in New York|Queens Public Library|the airport in Australia|Plutonic Airport}}
{{More citations needed|date=August 2012}}
{{Infobox software licence
| name = Q Public License
| image =
| caption =
| author = [[Trolltech]] AS
| version = 1.0
| copyright = Trolltech AS
| date = {{Start date and age|1999}}
| OSI approved = Yes
| Debian approved = No<ref name="debian"/>
| FSF approved = Yes<ref name="fsf"/>
| GPL compatible = No<ref name="fsf"/>
| copyleft = No<ref name="fsf"/>
| linking = <!-- Yes or No -->
}}

The '''Q Public License''' ('''QPL''') is a non-[[copyleft]] license, created by the company [[Trolltech]] for its [[free software]] edition of the [[Qt (software)|Qt]] toolkit and framework. It was used until Qt 3.0, until version 4.0 was released under the [[Free Software Foundation]]'s (FSF) [[GNU General Public License]] (GPL) version 2.

It fails the [[Debian Free Software Guidelines]],<ref name="debian"/> used by several [[Linux]] distributions, though it qualifies for the FSF's [[Free Software Definition]]; however, it is incompatible with the FSF's GPL,<ref name="fsf"/> meaning that products derived from code under both the GPL and the QPL cannot be redistributed.

== History ==
[[KDE]], a [[desktop environment]] for [[Linux]], is based on Qt. Only the free open source edition of Qt was covered by the QPL; the commercial edition, which is functionally equal, is under a pay-per-use license and could not be freely distributed. Meanwhile, the [[Free Software Foundation]] and authors of the GPL objected to the QPL as it was a non-copyleft license incompatible with the GPL.<ref name="fsf">{{cite web |url=https://www.gnu.org/licenses/license-list.html#QPL |title=Various Licenses and Comments about Them |publisher=GNU Project}}</ref> As KDE grew in popularity, the [[free software community]] urged Trolltech to license Qt under the GPL to ensure that it would remain free software forever and could be used and developed by commercial third parties. Eventually, under pressure, Trolltech dual-licensed the free edition of Qt 2.2 for use under the terms of the GPL or the QPL.<ref>{{cite web |title=Trolltech to Release Qt Under GPL |url=http://www.linuxplanet.com/linuxplanet/reports/2269/1/ |first=Kevin |last=Reichard |publisher=LinuxPlanet |date=September 4, 2000 |access-date=October 27, 2018 |url-status=dead |archive-url=https://web.archive.org/web/20180324223759/http://www.linuxplanet.com/linuxplanet/reports/2269/1/ |archive-date=March 24, 2018}}</ref>

== Adoption ==
Other projects that have adopted the Q Public License, sometimes with a change in the choice of jurisdiction clause, include:
* LibreSource is a versatile collaborative platform provided by artenum and dedicated to collaborative software development
* Jpgraph is a graph generation tool written in PHP that dynamically produces charts and graphs as image files for presentation on websites.
* [[Hercules emulator|Hercules]], a software implementation of the [[System/370]], [[ESA/390]], and [[z/Architecture]] mainframe computer architectures. On January 1, 2024, Jay Maynard announced a proposal to relicense Hercules under an [[MIT License]] on July 1, 2024.<ref>{{cite web |url=https://hercules-390.groups.io/g/group/message/8008 |title=Relicensing Hercules |work=hercules-390 mailing list |date=1 January 2024}}</ref> however this proposal was rejected as it did not have the unanimous approval of all of the copyright holders.
* [[Tgif (program)|Tgif]] switched from a free-of-charge non-commercial license to the Q Public License.

Prior projects using the Q Public License include:
* The [[OCaml]] compiler and related tools from Projet Cristal at [[INRIA]]. Since April 2016,<ref>{{cite web |url=http://ocaml.org/releases/4.03.html |title=OCaml 4.03 Release Notes}}</ref> OCaml is released under the [[GNU Lesser General Public License]] version 2.1 with [[Linker (computing)|linking]] exception.
* Computational Geometry Algorithms Library ([[CGAL]]) for versions 3.x. The CGAL [[Library (computing)|library]] is released under [[GNU General Public License]] (GPL) and [[GNU Lesser General Public License]] (LGPL) since CGAL version 4.0 (March 2012).

The [[Debian]] project rejects software covered by solely QPL<ref name="debian">{{cite web |url=http://lists.debian.org/debian-legal/2004/06/msg00131.html |title=Re: Bug#251983: libcwd: QPL license is non-free; package should not be in main |work=debian-legal mailinglist |date=8 June 2004}}</ref> (and not dual licensed with something else like the [[GPL]]) because of:
* A [[Forum selection clause|choice of venue]] clause
* Forced distribution to a third party
* Forced blanket license to the original developer

== Compliance ==
All legal disputes about the license are settled in [[Oslo]], [[Norway]],<ref>{{cite web|title=The Q Public License Version (QPL-1.0)|url=https://opensource.org/licenses/QPL-1.0|publisher=Trolltech|date=1999|quote=Disputes shall be settled by Oslo City Court.|access-date=October 27, 2018}}</ref> but it has never been legally contested.

== See also ==
{{Portal|Free and open-source software}}
* [[Open source license]]

== References ==
{{reflist}}

==External links==
* {{Official website|doc.qt.io/archives/3.3/license.html}}, version 1.0

{{Qt platform}}

[[Category:Qt (software)]]
[[Category:Free and open-source software licenses]]