A question about GPL
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There is a Linux tool called DVB-snoop which would save me a lot of work if I could use some of it's functions under Windows but it is under GPL. The equestion is - if I created a DLL then naturally the code of the DLL would be under GPL but what about and applications that use the DLL? I assume that if I made a LIB and linked it into my software then the software would come under GPL. Thanks in advance. Elaine (daintily diligent fluffy tigress)
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A software license is not worth the paper it is written on IF it can be legally circumvented. Problem: You want to use a GPL licensed program/library in your product. Conditions: Your product is not solely based on the GPL program and could be sold without it but would have better functionality incorporating it. Solution: 1) Person A (not you or your company) produces a DLL interface to the GPL program and releases this on the Web with full documentation, source code etc. to completly comply with the appropriate GPL license. 2) Your product calls Person A's DLL but the .LIB file and include files are based soley on documentation, not actual source files in Person A's product. 3) You release your product, but do NOT include Person A's product in the distribution. BUT your install could point to a Person A's Web site which could contain an automatic install. ------------------------------------------------------------------ Or as someone else pointed out, Person A could but a command line wrapper around the library and do as above. For all you GPL lovers you have to realise that you can't differentiate between a GPLed piece of code running in the same process space as a comercial piece of code or one running on the same CPU or the same computer or the same network. They ALL interact between each other and you either allow your free code to be run or not!
modified on Tuesday, March 24, 2009 8:31 AM
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I'm afraid that GPL (and GPL v3 in particular) is specifically designed to stop you from doing this. If the library is licenced under LGPL however you may be in luck with the DLL approach. Personally I consider the whole area so damn muddy that anything that even smells of GPL is barred from going anywhere near our codebase.
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We are in the same situation. The only way we use open source in our applications is if the license grants explicit free and unencumbered use for commercial purposes.
Software Zen:
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I'm afraid that GPL (and GPL v3 in particular) is specifically designed to stop you from doing this. If the library is licenced under LGPL however you may be in luck with the DLL approach. Personally I consider the whole area so damn muddy that anything that even smells of GPL is barred from going anywhere near our codebase.
Anna :rose: Having a bad bug day? Tech Blog | Anna's Place | Tears and Laughter "If mushy peas are the food of the devil, the stotty cake is the frisbee of God"
Lack of clarity on this issue is the main reason that development businesses are staying away from Open Source software. I'm a developer and my interest level completely drops the moment I start to have to consider the legal implications of using a specific dll. While I respect the aim to promote open development generally, the confusion surrounding this clause of the GPL should be simply removed. Banning people from keeping their software 'closed' source is actually counter productive to their stated aims.
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I think it depends on if you are creating a "derivative work" or not, and the exact definition of that is subject to lawyerly discussion. From http://www.ibm.com/developerworks/rational/library/edge/08/mar08/curran/index.html[^] GPLv3 adds more clarity with regard to what constitutes a derivative work. For example, GPLv3 states that if the program is "specifically designed" to work with a GPL-governed library, then the library is considered part of the overall work and the entire application is governed by the GPL. However, if one could swap out the GPL library for another library (i.e., if the application wasn't "specifically designed" to work with the GPL library), then it's not part of the overall work and would not be governed by the license.
This has been our interpretation too. Where I work, we concluded that to be on the safe side of the license, we needed to do a GPL-free implementation and provide the GPL one as an option... and then decided once we had the GPL-free implementation, there wasn't any value for us to do more work to do a GPL one -- none of our customers would care, and the open source community probably wouldn't have been very interested either. We didn't get the lawyers involved as the GPL seems pretty clear on this to even engineers like us :) We concluded anything less was a gray area, and and the managers decided we didn't want to take that risk.
patbob