GPL" redirects here. For other uses, see GPL (disambiguation).
GNU General Public License GPLv3 Logo.svg
GNU GPLv3 Logo
Author Richard Stallman
Latest version 3
Publisher Free Software Foundation
Published 29 June 2007
DFSG compatible Yes[1]
FSF approved Yes[2]
OSI approved Yes[3]
Copyleft Yes[2][4]
Linking from code with a different license No (except for software licensed under GPLv3 compatible licenses)[5]
Website gnu.org/licenses/gpl.html
The GNU General Public License (GNU GPL or GPL) is the most widely used[6] free software license, which guarantees end users (individuals, organizations, companies) the freedoms to run, study, share (copy), and modify the software. Software that allows these rights is called free software and, if the software is copylefted, requires those rights to be retained. The GPL demands both. The license was originally written by Richard Stallman of the Free Software Foundation (FSF) for the GNU project.
In other words, the GPL grants the recipients of a computer program the rights of the Free Software Definition[7] and uses copyleft to ensure the freedoms are preserved whenever the work is distributed, even when the work is changed or added to. The GPL is a copyleft license, which means that derived works can only be distributed under the same license terms. This is in distinction to permissive free software licenses, of which the BSD licenses and the MIT License are the standard examples. GPL was the first copyleft license for general use.
As of August 2007, the GPL accounted for nearly 65% of the 43,442 free software projects listed on Freecode,[8] and as of January 2006, about 68% of the projects listed on SourceForge.net.[9] Similarly, a 2001 survey of Red Hat Linux 7.1 found that 50% of the source code was licensed under the GPL[10] and a 1997 survey of MetaLab, then the largest free software archive, showed that the GPL accounted for about half of the software licensed therein.[11] Prominent free software programs licensed under the GPL include the Linux kernel and the GNU Compiler Collection (GCC). Some other free software programs (MySQL is a prominent example) are dual-licensed under multiple licenses, often with one of the licenses being the GPL.
David A. Wheeler argues that the copyleft provided by the GPL was crucial to the success of Linux-based systems, giving the programmers who contributed to the kernel the assurance that their work would benefit the whole world and remain free, rather than being exploited by software companies that would not have to give anything back to the community.[12]
On 29 June 2007, the third version of the license (GNU GPLv3) was released to address some perceived problems with the second version (GNU GPLv2) that were discovered during its long-time usage. To keep the license up-to-date, the GPL license includes an optional "any later version" clause, allowing users to choose between the original terms or the terms in new versions as updated by the FSF. Developers can omit it when licensing their software; for instance the Linux kernel is licensed under GPLv2 without the "any later version" clause.[13]
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