General Public License (GPL)

The General Public License (GPL) is a software license designed to ensure that software remains open and available to anyone who wants to use, modify, and distribute it. It was created by Richard Stallman, founder of the Free Software Foundation, in 1989 and has since become one of the most widely used software licenses in the world.

Purpose and Usage

The purpose of the GPL is to promote the idea of free software. Free software, in this context, refers to software that is free as in freedom, rather than free as in price. The GPL ensures that software remains free by requiring that any software that is derived from GPL-licensed software must also be licensed under the GPL. This means that anyone who uses, modifies, or distributes GPL-licensed software must also make their changes available under the same license.

The GPL is used primarily for software that is distributed under an open source license. Open source software is software that is made available to the public with its source code, allowing anyone to view and modify the code. The GPL is one of several licenses that are designed to protect the open source nature of software.

Key Features of the GPL

Copyleft

One of the key features of the GPL is the concept of copyleft. Copyleft is a way of ensuring that software remains free by requiring that any software that is derived from GPL-licensed software must also be licensed under the GPL. This means that anyone who uses, modifies, or distributes GPL-licensed software must also make their changes available under the same license.

In practice, this means that anyone who uses GPL-licensed software must also make their source code available to the public. This ensures that the software remains open and available to anyone who wants to use, modify, or distribute it.

Permissive Licensing

The GPL is a permissive license, which means that it allows anyone to use, modify, and distribute GPL-licensed software. However, it also requires that any software that is derived from GPL-licensed software must also be licensed under the GPL. This ensures that the software remains open and available to anyone who wants to use, modify, or distribute it.

Distribution

The GPL applies to the distribution of software, which means that anyone who distributes GPL-licensed software must comply with the terms of the license. This includes making the source code available to the public, and ensuring that any software that is derived from GPL-licensed software is also licensed under the GPL.

No Warranty

The GPL includes a disclaimer of warranty, which means that the software is provided “as is” without any warranty of any kind. This means that anyone who uses GPL-licensed software does so at their own risk, and that the Free Software Foundation and the creators of the software are not responsible for any damages that may result from the use of the software.

Compatible Licenses

The GPL is designed to be compatible with other open source licenses, which means that software that is licensed under the GPL can be combined with software that is licensed under other open source licenses. However, the GPL is not compatible with all open source licenses, and it is important to check the compatibility of licenses before combining software.

Versions of the GPL

There have been several versions of the GPL since it was first released in 1989. The most recent version is the GPL version 3, which was released in 2007. The GPL version 3 includes several new provisions, including provisions for digital rights management (DRM), compatibility with other open source licenses, and patent retaliation clauses.