Thread: Can GPL plugins be used in closed source front ends?

"For OpenMobile use only" is a bit against the "open" spirit isnt it?

As long as he does not actually release the dll, he is well within his distributing rights given by GPL to release a plugin using that dll, since OpenMobile GPL'ed the interface to the dll.

And fortunately, you have provided that DLL download free to anyone, so all he has to do is tell people where to get it, which again he is well within his rights, and since he isn't distributing it, it's on the end-user whether or not they agree to your EULA.



Edit: A caveat, this is for more lawyerish people than me to argue, but I'm fairly certain it is not against the rules to use a GPL plugin with a closed source system, as long as the interface is freely available which I think CF's is. If not, it would behoove the CF developers to make their interface public domain so as to allow GPL plugins to be developed.

Stretching it even further, if he were to write a white paper on how OpenMobile interfaces with the pandora DLL, someone could come along and take that and write their own plugin based off that (See: Clean room reverse engineering), and then have either a closed or open source pandora plugin which uses your DLL. Again, not providing the dll itself. You're not going to be able to keep this one to yourself for long, you knew that.

Originally Posted by justchat_1

The Pandora Plugin is not open source...and even if it was, GPL plugins cannot be used with a closed source plugin host (like centrafuse) - thats a violation of the license.

In the future I would also ask that when something is clearly licensed "License: For openMobile use only" that you respect that.

The project is hosted on SourceForge I'm not sure how "An open source, modular, C# driven, mobile computing front end" is closed source. However, I suspect that having Pandora plugin in your application is a biggie for you guys since CF does not have it, so I won't release this plugin unless I get an explicit permission from OpenMobile Open Souce community.

P.S. Not sure where it says "License: For openMobile use only". Please let me know

Originally Posted by nivanov

The project is hosted on SourceForge I'm not sure how "An open source, modular, C# driven, mobile computing front end" is closed source. However, I suspect that having Pandora plugin in your application is a biggie for you guys since CF does not have it, so I won't release this plugin unless I get an explicit permission from OpenMobile Open Souce community.

P.S. Not sure where it says "License: For openMobile use only". Please let me know

The spot where it was downloaded from:
http://openmobile.sourceforge.net/ma...fileinfo&id=42

but I thank you for respecting that.
OpenMobile itself is fully open source but not all of the plugins are (that would discourage a lot of plugin developers). There will likely even be paid plugins once the appstore is launched - we've had a lot of interest in that from third parties.

Originally Posted by malcom2073

"For OpenMobile use only" is a bit against the "open" spirit isnt it?

As long as he does not actually release the dll, he is well within his distributing rights given by GPL to release a plugin using that dll, since OpenMobile GPL'ed the interface to the dll.

And fortunately, you have provided that DLL download free to anyone, so all he has to do is tell people where to get it, which again he is well within his rights, and since he isn't distributing it, it's on the end-user whether or not they agree to your EULA.

Edit: A caveat, this is for more lawyerish people than me to argue, but I'm fairly certain it is not against the rules to use a GPL plugin with a closed source system, as long as the interface is freely available which I think CF's is. If not, it would behoove the CF developers to make their interface public domain so as to allow GPL plugins to be developed.

Stretching it even further, if he were to write a white paper on how OpenMobile interfaces with the pandora DLL, someone could come along and take that and write their own plugin based off that (See: Clean room reverse engineering), and then have either a closed or open source pandora plugin which uses your DLL. Again, not providing the dll itself. You're not going to be able to keep this one to yourself for long, you knew that.

Big surprise it would be you listing every way you can think of to get around our license. So lets clear up some facts for the next person who reads your post. This plugin is a stand alone closed source DLL, it contains no open mobile interface nor is it an open mobile plugin. It is closed source not GPL. Most importantly, should I find someone using it without permission I could change our API key and remotely kill that library.

Now if it was GPL it would still be illegal because it is GPL not LGPL and a non-GPL application cannot link to a GPL application under GPL. Doing so would qualify it as a combined work. Therefore it is technically illegal to use a GPL plugin in centrafuse. If you're still confused move this to a new thread...or Pm me

Mal is right on this one. GPL System -> closed plugin is illegal, while a Closed System -> GPL plugin is quite legal. The reason why the former is illegal is because most of the time, plugins require the usage of headers or 'interfaces' to work. This makes the plugin a derivative work. Derivative works that come from GPL'd code which is not also GPL (or compatible license) is explicitly disallowed by the GPL.

This is why most libraries you'll find are lgpl or some more lax licence like bsd or apache. These licenses allow you to derive from their code and not have to distribute the code.

Why you are calling this Assembly a plugin is beyond me. If it doesn't use any interface from OM or CF, it's not a plugin... it's a shared library. Calling it a plugin is leading to confusion. So when you call it an assembly, your right, a closed system cannot link to GPL'd libraries.

@Tidder: Thanks for the thread split

Originally Posted by tripzero

Mal is right on this one. GPL System -> closed plugin is illegal, while a Closed System -> GPL plugin is quite legal. The reason why the former is illegal is because most of the time, plugins require the usage of headers or 'interfaces' to work. This makes the plugin a derivative work. Derivative works that come from GPL'd code which is not also GPL (or compatible license) is explicitly disallowed by the GPL.

This is why most libraries you'll find are lgpl or some more lax licence like bsd or apache. These licenses allow you to derive from their code and not have to distribute the code.

Why you are calling this Assembly a plugin is beyond me. If it doesn't use any interface from OM or CF, it's not a plugin... it's a shared library. Calling it a plugin is leading to confusion. So when you call it an assembly, your right, a closed system cannot link to GPL'd libraries.

Plugin was the common name used by most front ends so thats what we went with but your right assembly would be the more technically correct name.

In any case, yea due to how plugins are loaded and executed (by all .net front ends) my statement was correct. Loading this library as a shared library qualifies it as a combined work. Long story short these plugins cannot be used by a close source application

One way or the other, I'm not releasing my CF plugin to the public. I might start working on my own interface library though, but it will be developed independently.

In order to show that the GPL has been violated, you have to show that some piece of IP is a derivative of an existing work that was licensed to the author (the author of the allegedly derivative work) under the GPL. I don't see where that happened... what am I missing?

An end user can't "create a violation" by combining two things that do not, by themselves, violate the GPL. The GPL is just a license to create derivative works with certain limitations (like releasing the source of the derivative work).

Originally Posted by NSFW

In order to show that the GPL has been violated, you have to show that some piece of IP is a derivative of an existing work that was licensed to the author (the author of the allegedly derivative work) under the GPL. I don't see where that happened... what am I missing?

You can't "create a violation" by combining two things that do not, by themselves, violate the GPL. The GPL is just a license to create derivative works with certain limitations (like releasing the source of the derivative work).

Not quite: http://en.wikipedia.org/wiki/GPL_linking_exception

I guesing that you're referring to this claim in particular:

Without applying the linking exception, code linked with GPL code must be using a GPL-compatible license.

That is a reasonably good rule of thumb, but it's not always true.

Suppose I write a Photoshop plugin and release it under the GPL. Photoshop links to my code at run-time, but Photoshop is not GPL'ed. According to that claim, this would constitute a violation of the GPL. But in fact it doesn't.