3. Grant of Source Code License

Both OSL and AFL

The term "Source Code" means the preferred form of the Original Work for making modifications to it and all available documentation describing how to modify the Original Work. Licensor hereby agrees to provide a machine-readable copy of the Source Code of the Original Work along with each copy of the Original Work that Licensor distributes. Licensor reserves the right to satisfy this obligation by placing a machine-readable copy of the Source Code in an information repository reasonably calculated to permit inexpensive and convenient access by You for as long as Licensor continues to distribute the Original Work, and by publishing the address of that information repository in a notice immediately following the copyright notice that applies to the Original Work.

Because the OSL and AFL are unilateral contracts , only the licensor makes promises. One of those promises is an explicit one to provide source code for any software he or she distributes under the license.

This section defines source code and guarantees its availability for the licensed software. Again, this provision is a commitment for the licensor, not the licensee, to disclose source code. Licensees must provide source code for their derivative works only if they are subject to the reciprocity obligation.

Source code in the OSL/AFL includes "documentation describing how to modify the Original Work." This goes beyond most other open source licenses to prevent the intentional obscuring of the source code. If the licensor has documentation about how to modify the work, it must be made available.

This documentation requirement does not include documentation on how to use the software. It only applies to documentation on how to modify the software.

These licenses provide two ways to satisfy the source code obligation. Either the licensor can include source code along with the executable software he or she distributes, or the licensor can provide an online copy that licensees can access.

Comparison to Other Licenses

Most of the licenses described in this book do not contain explicit source code requirements. The BSD, MIT, and Apache licenses, for example, permit licensors to distribute source code but do not require it.

The Artistic license requires the licensee to make source code available, but the license provides alternatives that would allow a licensee to avoid that obligation under certain circumstances.

The GPL requires licensees to provide source code for derivative works they distribute. (GPL section 3.) The definition of source code in the GPL does not include any documentation.

Under the MPL, licensees must provide source code for files containing derivative works they distribute. (MPL section 3.2.) That requirement can be satisfied by making the source code available online. Source code is defined to include "associated interface definition files, scripts used to control compilation and installation," and "source code differential comparison." The MPL expressly allows source code to be in compressed or archival form. (MPL section 1.11.)

Under the CPL, each Contributor grants the Recipient a license to the work "in source code and object code form." (CPL section 2[a].) The term source code is not defined. Contributors under the CPL must " inform licensees how to obtain it in a reasonable manner on or through a medium customarily used for software exchange." (CPL section 3.)