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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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26
votes
10answers
9k views

Is there a generally accepted “anti-copyleft” clause or license?

I would like to publish code for an application under an open source license like BSD, MIT, or Apache 2 which allows for changes and derivative works to be contributed back to the open source project ...
24
votes
4answers
7k 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?
24
votes
2answers
4k views

Do you violate the GPL if you provide source code that cannot be compiled?

In a recent question on programmers.SE†, it was asked whether a project is open source if it provides some source code but doesn't make it clear how to actually compile it. Consensus is that it'...
24
votes
2answers
758 views

What do I need to share if I include CC-BY-SA artwork in my software?

CC-BY-SA is a Creative Commons license with a copyleft clause - if you derive something from it, you must also provide the derivative under the same license if you distribute it. The relevant clause ...
22
votes
2answers
3k views

Must a company disclose proprietary source code if it violates a copyleft license?

What is the typical situation when some company is found to violate the some copyleft free software license and refuses to fix it? Can the company then be forced to disclose any proprietary code that ...
18
votes
4answers
603 views

What are the arguments for considering dynamic links to *not* constitute derivative works?

The status of programs which are dynamically linked with Copyleft licensed binaries (such as a .dll) is contentious. I have created two questions for each side of the debate. The other can be found ...
17
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? ...
16
votes
4answers
321 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 ...
16
votes
2answers
412 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 ...
15
votes
2answers
185 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 ...
12
votes
5answers
679 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 ...
12
votes
2answers
505 views

What are the arguments for considering dynamic links to constitute derivative works?

The status of programs which are dynamically linked with Copyleft licensed binaries (such as a .dll) is contentious. I have created two questions for each side of the debate. The other can be found ...
11
votes
2answers
3k views

What are software dependencies, and what are the implications of FLOSS dependencies for other projects?

How could I best explain software dependencies to a non-software, non-tech person? What are software dependencies, such as package dependencies or linking dependencies? And why does it matter to ...
10
votes
5answers
645 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 ...
10
votes
2answers
1k views

Will adding a BY-SA image to a blog post make the entire post BY-SA?

I tried to read the license deed but it was too advanced for me to understand. Consider these 2 situations, I take a CC-BY-SA image and upload it to my blogpost it as is, without any modification. I ...
10
votes
3answers
1k 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 ...
10
votes
1answer
66 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
993 views

So the GPL doesn't restrict the creator of the software in any way?

In another thread I started (Redhat buys Ansible), I am trying to figure out the economic value of a company transaction with respect to GPL'ed software. A few of the answers suggest that the owners ...
9
votes
3answers
198 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 ...
9
votes
3answers
613 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 ...
9
votes
1answer
288 views

Is a CLA only useful for copyleft licensed?

Is it useful to have a CLA when you e.g. use an MIT license for your project? I am just asking this, because when you use the MIT license you are already granted to sublicense it, so is a CLA ...
9
votes
1answer
403 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 ...
9
votes
2answers
2k views

If my R package uses GPL packages, does mine automatically inherit GPL?

I've built an R package that uses a mix of libraries licensed under GPL-2 and GPL-3. From what I've read, because of this dependency, my package will also have to be GPL. See here: https://www.gnu....
9
votes
1answer
661 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 ...
9
votes
1answer
318 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: ...
9
votes
2answers
75 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 ...
8
votes
4answers
746 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 ...
7
votes
1answer
335 views

GPL Licensed Woocommerce paid plugins

I have very basic question. I'm building website service where I want to use WooCommerce Subscription and Membership plugins. These plugins are paid on the official websites, but there is written ...
7
votes
2answers
750 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 ...
7
votes
1answer
814 views

What copyleft license should I use for my website's HTML/CSS/JavaScript?

If I made a somewhat complicated website, and I want it (the layout/JavaScript) to be under a copyleft license (but not the text), which license should I use? I want to pull others' forks so I have ...
7
votes
1answer
698 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
1answer
63 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. ...
7
votes
1answer
81 views

Can I license Latex code under GPL but the content under CC BY-SA?

I have written a non-trivial scientific text for university. It is written in Latex and I want to make the source available under GPL (v3 if that matters) so other can learn from my Latex skills. ...
7
votes
2answers
612 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 ...
7
votes
1answer
88 views

Creative Commons ShareAlike, weak or strong copyleft?

I am wondering whether Creative Commons ShareAlike is a weak or strong copyleft license. That is, does it allow linking with code with under a different license?
6
votes
3answers
165 views

How to deal with copy-left in source-code history prior open-sourcing?

Given the following situation: A software project is released as open-source under a non-invasive license (e.g., BSD 2/3 clause, Apache 2, ...). During the process, the entire Git repository is made ...
5
votes
2answers
239 views

Is there a good license for a libertarian programmer who's against intellectual property?

I know, I know, you're probably thinking CC0 or WTFPL or something along those lines. But the thing is, the way I see it, people have a right to redistribute anything, even if the author doesn't want ...
5
votes
3answers
125 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 ...
5
votes
3answers
207 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 ...
5
votes
2answers
349 views

If I use a public API endpoint that has its source code licensed under AGPL in my app, do I need to disclose my source?

If there's a public API server that has it's source code licensed with AGPL, and if I make an app that uses these public endpoints in some part of it, (entire application doesn't necessarily depend on ...
5
votes
1answer
57 views

In which cases must I relicense my product under the CC BY-SA license?

Because copyright law can encompass a huge range of scenarios and be unclear to talk about in abstract terms, I'm going to give concrete examples. I understand CC BY is a permissive license. All it ...
5
votes
1answer
304 views

Why to prefer permissive license over copyleft license?

In open source software/projects why do people release there codes with permissive license instead of a copyleft license. I mean the original author will not get back much (if anything at all ) if he ...
5
votes
1answer
533 views

How to best indicate license of source code and copying terms of binary when multiple licenses are involved?

Suppose I have some open source project which makes use of both GPL and MIT licensed components. The source code of my project is also MIT licensed (not copyleft). What is the right way to indicate ...
5
votes
2answers
1k views

Combining GPL with non-commercial license

I've been a hobbyist programmer for a long time, and only recently have I been writing code I've thought others might benefit from. Here's my conundrum: I'm a big supporter of the GPL, and I ...
4
votes
1answer
593 views

Are there any AGPL-style licences that require source code modifications to be public?

So my understanding of the AGPL, is that it requires modifications to be distributed to the users of the network service, but I'm looking for a licence that would require any modifications (non-...
4
votes
2answers
86 views

Is Open Public License suitable for libraries?

I would like to know if the Open Public License (OPL) allows library being bundled together or be a part of other code covered by other license (e.g. standard copyright - closed source code). I found ...
4
votes
2answers
80 views

Amount and way of publishing under share-alike license

I found a small C++ code example (containing a function) that is under CC-BY-SA-4.0 license. I am thinking about revising that example, extending it to multiple functions and using it in a much bigger ...
4
votes
1answer
81 views

Is there a license that “forces leaks”, so to speak?

I am looking for a license that "forces leaks", so to speak. What I mean by that is: A copyright holder must convey a copy of derivatives works they made using the license to anyone who requests it. ...
4
votes
1answer
56 views

Revert copyleft license without consent of all copyright holders

Let's say that Alice has started a project under a permissive license, e. g. MIT. Then Bob forked it and added some features. Now the project has two copyright holders, Alice and Bob. Then Bob decided ...
4
votes
1answer
1k views

Is dual licensing a software that contains gpl programs possible?

I have seen that there is a question about gpl and dual licensing, but I know copyleft can behave different depending on the shape of the software. so here's my question: I have a package of lua ...