The third license is a standard, copyleftcompliant license. It may be free software for the person receiving a copy initially, but it cannot be free software after that, because freedom 3 is prohibited from that point onwards in the distribution chain. Copyleft itself probably began in the work of mit computer expert richard stallman. The second form of copyleft licensing is the creative commons sharealike license this form of copyleft is more prominent in the art community.
Most copylefted software is issued under the gnu general public license. After opting into the copyleft licence, the source code is readily available, and it allows others to modify and develop the code. It was also the first license to implement the concept of copyleft, guaranteeing that gpled free software cannot become, or take part in, nonfree software. Copyleft is a form of licensing that can apply to computer software as well as a wide range of works including scientific discoveries, art, documents, etc.
The gnu general public license gnu gpl or gpl is a series of widely used free software licenses that guarantee end users the freedom to run, study, share, and modify the software. An example of a copyleft free software license is the often used gnu general public license gpl, also the first copyleft license. Both open source and copyleft allow for source code to be modified and distributed. For example, the bsd license is a noncopyleft open source license. There is an ongoing debate as to which class of license provides the greater degree of freedom. When an open source license is not copyleft, that means software released under that license can be used as part of programs distributed under other licenses, including proprietary nonopensource licenses. Users are permitted to engage in copying and distributing ed materials. Whats the difference between permissive and copyleft. The licenses were originally written by richard stallman, former head of the free software foundation fsf, for the gnu project, and grant the recipients of a computer program the rights of the free software. Before someone can license software under a copyleft license, they must first own the to that software, thus giving them the right to distribute it. So instead of putting gnu software in the public domain, we copyleft it. Bretthauer explains releasing software in the public domain means anyone can take it and appropriate it for their own use, including ing. Copyleft license legal definition of copyleft license by law insider.
With law, authors have complete control over their materials. The gnu general public license is often called the gnu gpl for short. Copyleft license legal definition of copyleft license by. In the gnu project, the specific distribution terms that we use for most software are contained in the gnu general public license.
This is a comparison of free and opensource software licenses. The use of software licenses for non software work is generally discouraged. Copyleft ensures that the three freedoms will also hold for all derived works. Copyleft licenses for computer software provide a reciprocal arrangement with users of free and open source software. Open source licenses are licenses that comply with the open source definition in brief, they allow software to be freely used, modified, and shared. Most discussions of free software licenses bore listeners. Most copylefted software is issued under the gnu general public license gpl, which was the first copyleft license and by far the most commonly used license for free software. An opensource license is a type of license for computer software and other products that allows the source code, blueprint or design to be used, modified andor shared under defined terms and conditions. The gnu free documentation license is another example of a copyleft non software license.
Free software licenses can be divided into two broad categories. I may only published derivative versions if i give all their users the same rights. Frequently answered questions open source initiative. This site itself is licensed under a copyleft license and has received contributions from experts around the world. License text english the gnu gpl is, according to various statistics, probably the most used free software license. Alternately, a document can be copylefted under different, or much simpler terms.
Some of the open source licenses use license agreements in the opposite manner to minimize or eliminate restrictions on users that might prevent the free use of the software, source code and, in certain instances, derivative works based on the. Copyleft says that anyone who redistributes the software, with or without changes, must pass along the freedom to further copy and change it. It can be applied to documents to make the open content for the public. Copyleft licenses enforce the publication of the source code under the copyleft license. Comparison of free and opensource software licenses. But the requiring of the first two isnt enough to make it copyleft. For a list of licenses not specifically intended for software, see list of free content licenses. Learn all about the history of open source copyleft licenses, what they. In fact, licenses are usually of such little interest that 85%of the projects on github fail to have one however, one aspect of licensing never fails to stir partisan responses. So i think it is important to understand how copyleft is or isnt. In fact, copyleft is grounded in the concept of, without which copyleft couldnt exist. The free art license grants the right to freely copy, distribute, and transform creative works without infringing the authors rights. Combinations of the three freedoms must be possible, too. A major difference between the set of permissive and copyleft free software licenses is that when the software is being redistributed either modified or unmodified, permissive licenses do not force the redistributor to open the modified source code.
Copyleft licensing definition of copyleft licensing by. Copyleft is a distinguishing feature of some free software licenses. Copyleft is the idea and the specific stipulation when distributing software that the user will be able to copy it freely, examine and modify the source code, and. Failure to adhere to software license agreement terms often incurs criminal charges related to licensed intellectual property ip and ed material. Copyleft licensing article about copyleft licensing by. Examples of noncopyleft free software licenses include the q public license, the x11 license, and the bsd licenses. Copyleft licensing is favourable for software coders. The comparison only covers software licenses with a linked article for details, approved by at least one expert group at the fsf, the osi, the debian project or the fedora project. John discusses the differences between permissiveness and copyleft as they apply to open source licensing. Copyleft is a general concept, and you cant use a general concept directly.
A strong copyleft license, such as the gnu gpl license, applies to all derived works and software components in the package. Copyleft is free software license requiring authors to permit some of their work to be reproduced. This license is aimed at giving and protecting all users unlimited freedom to use, study, and privately modify the software, and if the user adheres to the terms and conditions of the gpl, freedom to redistribute. If that happens, it has to be relicensed under the same exact terms as the opensource license, which will reduce the control that an enterprise has over their own software under many intellectual property laws. Free software is software whose source code is freely available to anyone to use for any purpose, including studying, copying, modifying, extending and giving away. An example of a free software license that uses strong copyleft is the gnu general public license. The free software definition specifies a fourth freedom that combines the preceding two distribute modified versions. The gnu free documentation license fdl is a form of copyleft intended for use on a manual. Information and translations of copyleft in the most comprehensive dictionary definitions resource on. In essence, software developed using opensource with copyleft code can become a derivative of that copyleft opensource software. Copyleft is the idea and the specific stipulation when distributing software that the user will be able to copy it freely, examine and modify the source code, and redistribute the software to others free or priced as long as the redistributed software is also passed along with the copyleft stipulation. Such licenses are usually called either noncopyleft or permissive. Copyleft licenses for software require that information necessary for reproducing and modifying the work must.
Copyleft definition of copyleft by the free dictionary. Copyleft license means any license of software meeting the open source definition as promulgated by the open source initiative or the free software definition as promulgated by the free software foundation that requires, as a condition to the use, modification, or distribution of such software, that such software be licensed, distributed or otherwise made available. Copyleft licensing synonyms, copyleft licensing pronunciation, copyleft licensing translation, english dictionary definition of copyleft licensing. Copyleft dictionary definition copyleft defined yourdictionary. Free and open source licenses include free software with no monetary usage charge, but. Free software licenses that use weak copyleft include the gnu lesser general public license and the mozilla public license. Copyleft is a type of license that attempts to ensure that the public. Unfortunately, there is no one metric to rule them all for the state of copyleft. Such software must usually be passed on with a copyleft license that requires successive users to accept and transmit copyleft and mandates that any modifications or improvements to the copylefted software be likewise transmitted under copyleft. A weak copyleft license, such as the gnu lesser gpl, applies only. Software released under the gpl also known as a copyleft can be copied, modified and distributed by anyone, as long as they, too, release it under a copyleft. As explained in the previous section, a copyleft license means downstream projects cannot add additional restrictions on the use of the software. Software licensing describes the legal rights pertaining to the authorized use of digital material. For example, copylefted software allows users to run, modify, copy, and distribute software on the condition that the source code remains open and publicly.
Copyleft definition, the right to freely use, modify, copy, and share software, works of art, etc. The gnu software license for example, and the copyleft license, are similar to the creative commons license. If a developer makes any modifications to this kind of software and then distributes that derivative version, they must. Many free software licenses are not copyleft licenses because they do not require the licensee to distribute derivative works under the same license. Copyleft is a legal concept drafted by programmer richard stallman, which allows the further distribution and modification of software released under the terms of a copyleft licence, but it does not allow proprietary developers to come and close the released software by. As much as open source licensing is about the grant of ip rights, its also grounded in politics, philosophy and public policy.
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