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“GPL” stands for “General Public License”. The most widespread such license is the GNU General Public License, or GNU GPL for short. This can be further shortened to “GPL”, when it is understood that the GNU GPL is the one intended.

The process involves adding two elements to each source file of your program: a copyright notice (such as “Copyright 2007 Butterfly Media Romania”), and a statement of copying permission, saying that the program is distributed under the terms of the GNU General Public License (or the Lesser GPL).

The copyright notice should include the year in which you finished preparing the release (so if you finished it in 2006 but didn’t post it until 2007, use 2006). You should add the proper year for each release: for example, “Copyright 2006, 2007 Terry Jones” if some versions were finished in 2006 and some were finished in 2007. If several people have helped write the code, use all their names.

Always use the English word “Copyright”; by international convention, this is used worldwide, even for material in other languages. The copyright symbol “©” can be included if you wish (and your character set supports it), but it’s not necessary. There is no legal significance to using the three-character sequence “(C)”, although it does no harm.

You should also include a copy of the license itself somewhere in the distribution of your program. All programs, whether they are released under the GPL or LGPL, should include the text version of the GPL. In GNU programs the license is usually in a file called COPYING.

If you have copied code from other programs covered by the same license, copy their copyright notices too. Put all the copyright notices together, right near the top of each file.

It is very important for practical reasons to include contact information for how to reach you, perhaps in the README file, but this has nothing to do with the legal issues of applying the license.

The copying permission statement should come right after the copyright notices. For a one-file program, the statement (for the GPL) should look like this:

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

For programs that are more than one file, it is better to replace “this program” with the name of the program, and begin the statement with a line saying “This file is part of NAME”. For instance,

This file is part of Foobar.

Foobar is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

Foobar is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.

This statement should go near the beginning of every source file, close to the copyright notices.

GNU General Public License
Link to GNU Homepage
Direct Link to GPL v3


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