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FAQ License Choice

Open Source Software license

We provide Open Source Software license and legal materials via this page.


License Choice

Q1: Masao favors the terms of a specific license--for example, GPL--but finds that some articles in the license do not fit his needs. If he takes those articles away, will he still be able to claim that the modified license is the same as the original GPL?

A1: He will not. A license is a contract between the author of a work (the licensor) and the user of that work (the licensee). An author can decide the terms of a contract. He or she can choose a popular license (such as GPL) or arrange with the user a set of terms different from popular licenses. When the author and the user agree on the terms, the licensing contract between the two parties is made.There is some problem, however, with Masao’s case. He favors the terms of a popular license X, but some of its terms do not fit his particular needs. What he can do is to use X as a reference and to create a new licensing contract—let’s call it license Y—by adding, removing or modifying the terms of license X. Once any addition, removal or modification is done, however, Masao is no longer able to claim that his licensing terms are called X. By claiming so, he misleads users into believing that Masao’s contract terms are those of X. They will not be able to know that Masao’s terms are actually different from license X. This in turns will cause the two parties to have different interpretations of the licensing terms and can even cause disputes.


Q2: Masao would like to create a module C by modifying modules A and B. Modules A and B are licensed under licenses X and Y. Will Masao be able to do so? In addition, should Masao release module C under license X or Y, or will he be able to release it under a license that is compatible with licenses X and Y? If licenses X and Y are not compatible with each other in nature, what should Masao do?

A2: It depends on whether the licenses involved are compatible with each other. Masao creates a module C by modifying modules A and B. Module C is, according to the Copyright Law, the derivative work of both modules A and B. To be able to create such a work, Masao must have the permission to modification from the respective authors of modules A and B. In addition, whether Masao is able to integrate the two modules into one will depend on the compatibility of the respective licensing terms (licenses X and Y) of modules A and B.If the terms on derivative work in both licenses do not conflict—say, if license X does not say that a work must not be integrated with another work under license Y and vice versa—Masao will be able to integrate modules A and B into module C, since licenses X and Y are compatible with each other. If that is the case, Masao will be able to, as the author of module C, release the module under either license X, Y, or any other license that is compatible with licenses X and Y.On the other hand, it is possible that licenses X and Y are not compatible with each other. For example, in license X there may be articles saying that the distribution of a work must be accompanied with the releasing of its source code, whereas in license Y there is no such requirement. In addition, license X may disallow any commercial use of a work, whereas license Y does not prohibit it. If Masao would still like to integrate both modules A and B into module C, either he has to release his work under license X, which is more strict, or he has to look for another license that is compatible with both licenses X and Y.Since there are many popular free/open source software licenses, and since determining compatibility requires careful legal interpretation of the licenses involved, we recommend Masao seek professional help for his case.


Q3: Masao has developed a program Foo, which uses Cygwin Library by linking the library into the executable file. Cygwin Library is released under the GPL. Program Foo also links another library Bar that is developed by Masao. Here are two questions: (1) Since Foo uses the Cygwin Library, which is released under GPL, must Foo (including the final product, or the executable file, and its source code) also be released under GPL? (2) Must the library Bar, which is independently developed by Masao, also be released under GPL?

A3: GNU General Public License (GPL) covers both the work released under the license and its derivates as a whole. According to its Section 2, Paragraph 2: “These requirements apply to the modified work as a whole.” If a certain identifiable part of a work is not derived from another work that is released under GPL, that identifiable part does not need to be released under GPL. To put it in plain words:

(1) Since Foo (statically) links to Cygwin Library, and since the Cygwin Library is released under GPL, Foo must therefore be released under GPL;

(2) When Masao distributes Foo, if he also distributes Library Bar as a part of Foo, Bar must also be released under GPL; on the other hand, if Masao distributes Bar as a library that is independent from Foo, Bar needs not to be released under GPL.


Q4: Two questions: (1) Program Bar is developed by Carol. If Masao wants to use some part of Bar in his program Foo, does he need to obtain the permission from Carol? (2) If Bar is released under License Y, and Masao chooses to release Foo under License X, under which license should Masao choose to release the resulting work—the work that results from the integration of Foo and Bar?

A4: (1) Masao needs to obtain the permission from Carol if he wants to uses part of Carol’s program Bar in his program Foo. The kind of permission he needs to get depends on what Masao is going to do.If Masao does not modify Bar, that is, if Masao simply uses Bar by duplicating all or part of Bar, he only needs to get the permission for reproduction of Bar from Carol. If Masao modifies Bar, either wholly or partially, and later puts the modified Bar into his program Foo, he will need to obtain the permission for modification. If Masao not only uses Bar in Foo by modifying Bar but also desires to distribute Foo, he will need not only the permission for modification but also the permission for distributing Bar.It is commonplace for software developers to use others’ programs, either wholly or partially. In principle, any such use requires permission from the author of the original work. The kind of permission—be it that of reproduction, modification or distribution—will depend on how the developer in question makes use of others’ programs.The majority of free/open source software licenses have already stated in their terms that the user of the software in question is granted the rights of reproducing, modifying and distributing the software. So long as the user observes the terms, there should be no infringement involved.

(2) Masao integrates his own program Foo and Carol’s Bar and would like to combine them into a new Program Loremipsum If Foo is released under License X and Bar under Y, and if licenses X and Y are not compatible with each other, Foo and Bar will not be able to be integrated into Loremipsum. If Masao can obtain permissions from Carol, Loremipsum will be able to be licensed under a license that is neither X nor Y. To take one step further, upon Carol’s agreement, Loremipsum can even be licensed simply under license Y. The same could be said of Masao’s Foo if Carol seeks Masao’s agreement. (For issues on compatibility, please also refer to Q2 and Q3.)


Q5: Carol has a project Blah, which makes use of the modules A, B, C, which are in turn respectively released under licenses X, Y and Z. Carol chooses to release project Blah under License W, but licences X and W are not compatible with each other. So the questions are: (1) Will Carol breach the licensing terms of X, which is chosen by Masao for his module A? (2) Is Carol able to cite the disclaimer articles of licence W, and disclaim every responsibility from Masao?

A5: (1) What Carol has done already breaches the agreement made between her and Masao. Licenses W and X are not compatible, and Carol’s project Blah makes use of module A. Carol, however, does not observe the licensing terms of X and choose an incompatible license W to release her project. By doing this, Carol breaches the agreement with Masao that is stated in license X.

(2) Carol will not be able to cite the disclaimer articles in license W to disclaim from Masao the liabilities of breaching license X. This is because license W is a set of terms between users of project Blah and the project’s developer (i.e. Carol), not between the project’s developer (Carol) and the developer of a module used (i.e. Masao).Note: Since free/open source software allows another person to reproduce, modify and distribute freely the source code of a program, it is not sensible to let the author of the work bear the burden of liabilities. In addition, such legal responsibilities should come with matching rewards. Since free/open source software usually allows another person to use it gratis, most free/open source software licenses come with disclaimer articles. This is meant to be an incentive of making source code open. Such disclaimer often comes in such form (here we cite the example for article 12 of GPL):IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES


Q6: (1) Masao has developed a program A that is released under a free/open source software license. A company now has commercial interests in software A. Can Masao talk with that company over a commercial license (in which, for example, Masao may charge the company loyalties)? (2) If software A is not entirely developed by Masao and in the process of development Masao has made use of module B made by another person, and module B in turn is released under free/open source software license Y, and software A is released under a free/open source software license upon its own completion. In such case, will Masao still be able to talk with other companies over a commercial license for A?

A6: (1) Yes, Masao may talk with that company over a commercial license. Masao is the copyright holder of software A. Under the precondition that no other existing module is used and the software is independently developed, Masao can grant the rights of use of A under a different license (this is called double licensing). It is recommended, however, that Masao inform proactively the company in question that software A is already released under a free/open source software license. Since software license is a kind of contract, so long as Masao and the licensee reach an agreement, the contract stands. Besides, Masao can release software A under two licenses in the very beginning, one free/open source software license and another a commercial license.

(2) Yes, under the perquisite that the commercial licensing terms are compatible with the terms of license Y. Since Masao’s software A in this case uses an existing module B developed by another person, the choice of A’s licensing terms has to be agreed upon by module B’s author (under the licensing terms of B). In some licenses such as the MIT license, however, the original work’s author has already granted to the person who modifies the work (e.g. Masao in this case) the freedom to choose a license to his/her own liking. So in this case Masao’s choice has already been agreed upon by the author of the module in question (for compatibility issues, please refer to Q2 and Q3).

Category: FAQ