- The GPL Bargain
- Copyleft and Reciprocity
- Policy Objectives
- The Preamble to the GPL
- GPL as Template
- The GPL Applies to Programs
- Linking to GPL Software
- Copyright Law and Linking
- The LGPL Alternative
- GPL Grant of License
- Access to Source Code
- "At No Charge"
- Other Obligations in the GPL
- The GPL and Patents
- Accepting the GPL
GPL as Template
The GPL devised an elegant solution to the problem of associating a generic software license with specific software. Instead of placing the name of the software in the license (as is usually and inconveniently done with proprietary and many other open source software licenses), it requires that a notice be placed in the software by the copyright holder saying, "it may be distributed under the terms of this General Public License." Where this notice is to be placed is not specified, but at the end of the GPL, in a separate nonbinding section entitled "How to Apply These Terms to Your New Programs," the GPL suggests that the notice should be at the start of each source file.
The GPL is thus a template license, applicable to software by any author who chooses to use it. All a licensor has to do to use it is to include a notice in his or her source code saying, in effect, "I'm licensing this software to you under the GPL." But which GPL? There was at least one earlier version and there are promises of another version to come. How can a licensor indicate which version of the GPL applies to the licensed software? Here's how the GPL handles that situation:
If the Program specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Program does not specify a version number of this License, you may choose any version ever published by the Free Software Foundation. (GPL section 9.)
Some licensors object to giving anyone, including the Free Software Foundation, the opportunity to change the licensing rules for his or her own software after the software has already been distributed under a specific license. Those licensors, then, should be explicit in the notices they place in the software, being careful to identify that they are "licensing this software to you under the GPL version 2" if that is specifically what they intend.