GPL license

GPL license overview

As a developer, you may use many libraries and software licensed under the GPL.

In this article, I want to give a high-level overview of this license and tell you what you havecan doUsing GPL software, you willCan not doUsing GPL software, and youMust doWhen you rely on it.

Historically, GPL is the core of open source software. It was originally created by Richard Stallman in 1989 forGNU projectIt is a free software version of the proprietary UNIX operating system.

Since its launch, GNU has had a huge impact on our industry. What we call servers and computers running "Linux" are actually running GNU/Linux systems. Linux is the kernel ("core"), and a large part of the kernel is composed of software built under the GNU Project framework, such asThumpAnd the GNU C library. The complete list of GNU packages isvery longAnd include gems you might use, such as wget, nano, gcc, gimp, emacs, gtk+, etc.

Note: Android uses Linux as its kernel, but does not include GNU software, and includes proprietary software on top, sovery muchIt is different from the desktop GNU/Linux distribution. In addition, the open source part of Android is licensed under the Apache 2.0 license instead of the GPL.

Note: This article discusses the latest version of the GPL license v3. Finally, you will find some key differences in GPL v2.

Advantages of GPL v3 software manufacturers

As a software manufacturer licensed by GPL v3, you are not responsible for the losses caused by the use of the software.

youwere ableIf necessary, you can add a warranty to the software, but by default, you are not responsible.

Similarly, a great benefit is that software licensed under the GPL cannot be re-licensed under a more lenient license.

What must be provided as a GPL v3 software manufacturer

As a GPL software manufacturer, you must:

  • Include a complete copy of the GPL license version in the package you distribute
  • Include your copyright
  • Include disclaimer

If you distribute an executable version of the software, you must provide the source code of the software to anyone who requests it.

In addition (GPL v3 only) if the software is part of a consumer device, installation instructions must be provided to allow anyone to modify the software, build the binary file and reinstall it.

If you want to redistribute a modified version of GPL software, you must also:

  • Contains the original version copyright
  • Include instructions for obtaining the original version
  • Include a list of changes made to the original software

Advantages of GPL v3 software users

As a user of GPL v3 software, you have a lot of freedom:

  1. You can use GPL software for commercial purposes
  2. You can modify the software and create derivative works
  3. You can distribute the software and any derivative works produced without asking for permission or paying to anyone

In addition, only for GPL v3 (not GPL v1 or v2), you can safely use any patents owned by the contributors of the software you use (no matter what kind of patent you have, they give you the right to use the software built-in, they Cannot sue you for using it)

Disadvantages of GPL v3 software users

You cannot change the license of the code received in the form of GPL. You can modify the software, but you cannot change the license to other content.

Once the software is licensed through the GPL, it will always be accompanied by the license.