Practice of mandating free use in all derivatives of a work
Copyleft symbol
Intellectual property
Authors' rights
Copyleft
Copyright
Database right
Farmers' rights
Geographical indication
Indigenous intellectual property
Industrial design right
Integrated circuit layout design protection
Moral rights
Patent
Peasants' rights
Plant breeders' rights
Plant genetic resources
Related rights
Supplementary protection certificate
Trade dress
Trade secret
Trademark
Utility model
Related topics
Abandonware
Artificial intelligence and copyright
Brand protection
Copyright abolition
Copyright troll
Criticism of copyright
Bioprospecting
Biopiracy
Idea–expression distinction
Limitations and exceptions to copyright
Fair dealing
Fair use
Paraphrasing
Right to quote
Orphan work
Patent troll
Pirate Party
Public domain
Outline of intellectual property
Outline of patents
Higher categories: Property and Property law
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Copyleft
Articles on copyleft licensing
Topics
Copyleft
Open-source license
Free-software license
Free and open-source software
Royalty-free
Higher categories: Software, freedom
Category:Free and open-source software licenses
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Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in derivative works. In this sense, freedoms refers to the use of the work for any purpose, and the ability to modify, copy, share, and redistribute the work, with or without a fee. Licenses which implement copyleft can be used to maintain copyright conditions for works ranging from computer software, to documents, art, and scientific discoveries, and similar approaches have even been applied to certain patents.[1]
Copyleft software licenses are considered protective or reciprocal in contrast with permissive free software licenses,[2] and require that information necessary for reproducing and modifying the work must be made available to recipients of the software program, which are often distributed as executables. This information is most commonly in the form of source code files, which usually contain a copy of the license terms and acknowledge the authors of the code. Copyleft help ensuring everyone's rights to freely use the product but is prohibited from owning, registering copyright and earning royalties from copyright.
Notable copyleft licenses include the GNU General Public License (GPL), originally written by Richard Stallman, which was the first software copyleft license to see extensive use;[3][non-primary source needed] the Mozilla Public License; the Free Art License;[4][non-primary source needed] and the Creative Commons share-alike license condition[5][non-primary source needed]—with the last two being intended for non-software works, such as documents and pictures, both academic or artistic in nature.
Wikipedia is copyleft under the Creative Commons Attribution-ShareAlike license, as mentioned at the bottom of the page.
^Newman, John (29 December 2011). "Copyright and Open Access at the Bedside". NEJM. 365 (26): 2447–2449. doi:10.1056/NEJMp1110652. PMID 22204721.
^Troan, Larry (2006). Open Source from a Proprietary Perspective(PDF). Red Hat Summit. Nashville: Red Hat. Archived from the original (PDF) on 22 January 2014.
^Stallman, Richard (29 June 2007). "GNU General Public License". GNU Project. Retrieved 1 May 2017.
^"Free Art License 1.3". Copyleft Attitude. Retrieved 6 October 2021.
^"Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)". Creative Commons. Retrieved 14 August 2015.
Copyleft is the legal technique of granting certain freedoms over copies of copyrighted works with the requirement that the same rights be preserved in...
BSD-like or BSD-style license, is a free-software license which instead of copyleft protections, carries only minimal restrictions on how the software can...
released under a permissive license may be referred to as "copycenter". Copyleft is a play on the word copyright and describes the practice of using copyright...
rights reversed is a phrase that indicates a release of a publication under copyleft licensing status. It is a pun on the common copyright disclaimer "All rights...
proprietary) software without being required by the terms of a strong copyleft license to release the source code of their own components. However, any...
restrictions on reuse and therefore has high license compatibility. Unlike copyleft software licenses, the MIT License also permits reuse within proprietary...
licenses, or copyleft, that guarantee end users the four freedoms to run, study, share, and modify the software. The license was the first copyleft for general...
generally find the same set of software to be acceptable, but sometimes see copyleft as restrictive. They generally advocate permissive free software licenses...
negotiate to combine code. Copyleft licenses are commonly deliberately incompatible with proprietary licenses, in order to prevent copyleft software from being...
on the use and distribution of covered software. This is in contrast to copyleft licenses, which have share-alike requirements. The original BSD license...
The GNU Free Documentation License (GNU FDL or simply GFDL) is a copyleft license for free documentation, designed by the Free Software Foundation (FSF)...
The GNU Affero General Public License (GNU AGPL) is a free, copyleft license published by the Free Software Foundation in November 2007, and based on the...
proprietary. Some copyleft licenses block other means of turning software proprietary. Copyleft is a general concept. Copylefting an actual program requires...
financial profit is expected to be much lower in a business model utilising copyleft works only than in a business using proprietary works.[opinion][better source needed]...
based on the principle of copyleft, a kind of reciprocity: any work derived from a copyleft piece of software must also be copyleft itself. The most common...
"weak" copyleft. "Weak" copyleft programs typically allow distributors to link them together with non-free programs, while "strong" copyleft strictly...
copyright notice and disclaimer. The Apache License is permissive; unlike copyleft licenses, it does not require a derivative work of the software, or modifications...
abilities and willingness". Copyleft licenses are institutions which support a knowledge commons of executable software. Copyleft licenses grant licensees...
adopters license related improvements they develop under the same terms. Copyleft-style licensors seek "continuous growth of a universally accessible technology...
for copyleft licenses, especially the GPL, that allows derivative works only when permissions are preserved in modified versions of the work. Copyleft licenses...
share-alike (copyleft Licenses). An example of a copyleft free software license is the often used GNU General Public License (GPL), also the first copyleft license...
Day. Public records Center for the Study of the Public Domain Copyfraud Copyleft Copyright status of works by the federal government of the United States...
circle), and is used to designate copyright in a sound recording. The copyleft symbol 🄯 is a backwards capital letter C in a circle (copyright symbol...
The Server Side Public License (SSPL) is a source-available copyleft software license introduced by MongoDB Inc. in 2018. It includes most of the text...
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