Questions tagged [copyleft]

For questions about the copyleft concept (also known as Share-Alike), a concept that promotes or enforces the use of the same or compatible license for derived works.

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8
votes
4answers
1k views

Does physically removing GPL code relieve combined work from GPL publication requirements?

Here's the scenario. Alice crafted a compression library and published it under GPL. Bob crafted a font processing library which uses pieces of code from Alice's library and ... let's call it overly ...
18
votes
2answers
619 views

Are Copyleft and Share-Alike synonyms?

Copyleft and Share-Alike are two very similar types of licences. Here is how Wikipedia defines them: Copyleft (a play of the word copyright) is the practice of offering people the right to freely ...
9
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3answers
226 views

Using copyleft licenses for non-programming purposes

Well, what I love about GPL is that any derivative work using GPL-licensed work also needs to be GPL licensed, which guarantees that derivative work is open-source, i.e. when requested the source of ...
18
votes
4answers
3k views

What is copyleft?

Straight up: I've never heard of the term 'copyleft' before. The fact that I get that little red squiggle under it tells me it's not really a word. Concisely, my question is, what does it mean to you? ...
3
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2answers
89 views

JPEG comment to convey Copyleft Multi-Licenced Copyright Notice

This question is related to Copyleft Multi-Licenced Copyright Notice. I upload pictures on commons.wikimedia.org and I want to facilitate the reuse but I want derivatives stay "libre". Therefore I ...
3
votes
2answers
66 views

Copyleft Multi-Licenced Copyright Notice

I want to allow any usage/modification/distribution of my work except with the restriction that my work and derivatives must stay "libre". Therefore I think the right way is to publish my work under ...
27
votes
4answers
12k views

What's the difference between permissive and copyleft licenses?

I've heard both terms thrown around, but I'm a bit unclear as to how the licenses differ. How is copyleft different to a permissive license? Is copyleft just the standard for open source licenses?
3
votes
1answer
149 views

Is a ROM image an “executable file” for GPL purposes?

I am planning to include a program covered by the GNU General Public License and a GPL-incompatible program in a collective work designed for a machine that executes programs from a cartridge ...
10
votes
5answers
961 views

Someone is violating the copyleft license, they are refusing to give me the source code even though they are required to!

This person has a piece of open source code which is released under a copyleft license. They are required to give me this code, but numerous times they have refused. I am stuck because I need this ...
-2
votes
1answer
242 views

What's “use CDDL for things already under CDDL” mean?

Circa 2006, blogs.sun.com/chandan/entry/copyrights_licenses_and_cddl_illustrated says, in comparing EULA, GPL, CDDL and BSD, that one must "use CDDL for things already under CDDL". But what does it ...
9
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1answer
215 views

Good licence for a new documentation project

I want to publish a lot of documentation on programming and other similar topics I have been writing over the years. The documentation consist of explanations, diagrams, exercises and code examples. ...
5
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3answers
283 views

Does a CC BY-SA 4.0 specification lose any AGPL3+ benefits?

If I release a program specification [1] under the AGPL, and the program itself under the AGPL, the two are obviously compatible: I can develop them at the same time, copy text (for example, method ...
9
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1answer
505 views

Can I preserve exceptions in GPL 3?

GPL 3 allows adding additional clauses, such as exceptions, as long as such exceptions grant additional privileges. But if I distribute software under GPL 3 with exceptions, are those exceptions ...
12
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3answers
2k views

How can I detect if someone is breaking my license terms?

If this question is about what we are supposed to do if someone is breaking the terms of a software license, I would like to know how I can know if some is doing so. Suppose that I'm writing a ...
13
votes
5answers
708 views

Appropriate licence for later merging back

I am a library developer. I want to open source it soon, but I'm not sure what license will work best for me. My main concerns are: I want to provide a commercial license for somebody who is willing ...
7
votes
2answers
675 views

Are there examples of proprietary software that functionally depends on copylefted software?

This question is a follow-up on: Are there examples of proprietary software that functionally depends on free software? Please note that this is not a duplicate, as "copylefted" (and some more, see ...
9
votes
1answer
995 views

How does the GPL's linking restriction apply when using a proprietary library with GPL'd interpreted code?

General description: Can I create Python software that will dynamically link against a closed-source library that has a C API (the Python interpreter is not copyleft) and will also utilize a GPL ...
17
votes
4answers
453 views

Does a host application's license apply to plug-ins written for it?

This was prompted by another question which reminded of a past experience. Consider the following: An open-source project supports a plug-in architecture The project is released under a copyleft ...
7
votes
1answer
774 views

What's the typical practice for cases when OSS license violation is found and fixed?

Suppose I ship binaries of a closed source product and it just so happens that there's a piece of GPL source code inside my giant codebase that I'm unaware of. At some point I find this GPL code and ...
7
votes
2answers
1k views

Which standard copyleft licences can be applied to Unity assets?

I would like to release a framework for Unity under a copyleft licence but have some concerns. My goal is for people to be able to use the framework to develop their own projects and only be required ...
9
votes
3answers
648 views

Will copyleft help me control what others are able to do with my code?

Given that I've written a program that I want to release as Open Source / Free Software (as defined by the OSI and the FSF), will choosing a copyleft license help me control what others are able to do ...
5
votes
3answers
155 views

How do I stop republication under a different license?

Suppose I am finishing an open source software. I am about to publish it but I just have to choose the license. I want it to be a CC-BY license but I don't want anyone to republish it under ANY other ...
11
votes
1answer
406 views

Why is the Reciprocal Public License OSI-approved but not FSF-approved?

The Reciprocal Public License (RPL) is interesting in that it is the only license both OSI-approved and not FSF-approved. It is a copyleft license similar to GPL but with a "reciprocal" clause: ...
10
votes
1answer
71 views

Is there a share-alike licence for media which specifies that the project files must be published as well as the finished media?

Is there any licence that can be used for artistic projects (images, music, etc.) that are similar to CC-BY-SA, but with the additional constraint that not only the resulting work should be made ...
9
votes
2answers
91 views

Does the licence of the database used have an influence on the final licence of the product?

Assume a standard server-side Web application. Database, backend, frontend. It's basic knowledge that one should check the licences of the libraries used before deciding on the license for the final ...
15
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2answers
219 views

Jurisdictions without compatible copyright law

Free software licences such as GPL depend on copyright law in order to be legally enforcable. Are there jurisdictions in which the law does not enforce such licenses, allowing the license to be ...

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