The GNU General Public License or better known by its English name GNU General Public License or simply its acronym GNU GPL according to AbbreviationFinder, is a license created by the Free Software Foundation in 1989 (the first version), and is mainly aimed at protecting the free distribution, modification and use of Software. Its purpose is to declare that the software covered by this license is Free Software and to protect it from appropriation attempts that restrict those freedoms to users.
There are several “sister” licenses of the GPL, such as the GNU Free Documentation License (GFDL), the Open Audio License, for musical works, etc., and other less restrictive ones, such as the MGPL, or the LGPL (Lesser General Publical License, formerly Library General Publical License), which allow dynamic linking of free applications to non-free applications.
The GPL license, being a document that grants certain rights to the user, takes the form of a contract, which is why it is usually called a license agreement or license agreement.   In countries with an Anglo-Saxon tradition there is a doctrinal distinction between licenses and contracts, but this does not occur in countries with a civil or continental tradition. As a contract, the GPL must meet the legal requirements for contractual training in each jurisdiction.
The license has been recognized by courts in Germany, particularly in the case of a judgment in a Munich court, which positively indicates its validity in civil law jurisdictions.
Terms and conditions for copying, distribution and modification
This License applies to any program or other type of work that contains a notice posted by the copyright holder stating that it can be distributed under the terms of this General Public License. Hereinafter, “Program” will refer to any program or work that meets this condition and “work based on the Program” will refer to either the Program or any derivative work from it under copyright law. That is, a work that contains the program or a portion of it, either literally or with modifications and / or translated into another language. Therefore, translation is included without limitation in the term “modification”. Each licensee (licensee) will be referred to as “you.”
GPL version 3
At the end of 2005, the Free Software Foundation announced that it was working on version 3 of the GPL license, the first draft of which was submitted for public discussion on January 16, 2006. The discussion lasted 18 months, having published four drafts. Finally, the official version was published on June 29, 2007 and is accessible through the GNU Portal. The new version includes the following aspects:
- The various ways in which someone could take away freedoms from users.
- Ban the use of free software in systems that use the so-called Digital Rights Management or DRM, a system criticized by the free software community.
- Resolve ambiguities and increase GPLv3 compatibility with other licenses.
- Facilitate their adaptation to other countries.
- Include clauses that defend the free software community from the misuse of software patents.
- Show registered users.
Many free licenses such as the MIT License, and the GPL, are compatible with the GPL (see full list in external links). This means that code licensed under the GPL can be combined with code that is under a compatible license without any problem, since the resulting code must satisfy the conditions of both licenses. However, other licenses classified as free are not compatible with the GPL, which makes code reuse difficult; For this reason, Free Software developers are encouraged to license their code under the GPL or licenses compatible with the GPL, being able to take advantage of the advantages that this entails.
There is a proliferation of free licenses that add some kind of condition to another GPL-compliant license (on which they are based), making it difficult to determine whether or not the new license is GPL-compliant. This requires resorting to experts in the field, which was what was originally intended to be avoided, so this practice is not recommended.