4 ms·

You're free to link to compiled GPL libraries. There is nothing forcing you to change the license of your product unless you intend to integrate the sourcecode.

kazinator 11y ago
I also believe this, but it is not an established fact. The GPL does prohibit it, and so whether that is actually enforceable has to be tested in a court of law. So you are in fact not free to do this, if you have a boss above you who cares dearly about the company steering clear of hot water. I'd be willing to testify as a technical expert in a court of law that the GPL cannot reasonably rule out dynamic linking; that dynamic linking to a program is a form of use (like invoking a command line and passing it arguments) and not integration. The proof is that dynamically linked components can be replaced by clean-room substitutes which work exactly alike, or at least well enough so that the main software can function. For example, a program can be shipped with a stub library which behaves like GNU Readline (but perhaps doesn't have all its features). The users themselves can replace that with a GNU Readline library. Thus, the program's vendor isn't even redistributing the GPL'ed component. They can provide it as a separate download or whatever. However, if they were to include a GNU Readline binary for the convenience of the users, then the program supposedly infringes. This is clearly nonsense.
- belorn 11y ago
  The problem with that line of thought is that the courts don't care if its use or integration, but if the resulting work depends on someone else work. The word used in copyright law is transform, adapt, recast, and such changes requires additional copyright permission. For example, if I buy a painting and cut it into pieces and rearrange them, I actually need an additional license beyond what I got from purchasing the copy. Components can not be cleanly viewed as separate when dealing with copyright. You can also turn this around and ask if its legal to use process call within a other program without invoking the need for additional permissions. FSF view that it should be legal, but it has never been tested. By now however an industry standard has formed around the FSF guidelines and most courts would just look at it when deciding. This is what commonly happen when no one go to court to find out what the rules actually should be.
  - kazinator 11y ago
    > but if the resulting work depends on someone else work. Yes, so obviously your argument cannot be that "in theory, we could replace this with a workalike". You better have the workalike, and that's what you should be shipping. A powerful argument that you aren't infringing is that your shipping media are completely devoid of the work. > don't care if its use or integration For the sake of the GPL, they must care in this case, because the GPL specifically abstains from dictating use; it governs redistribution! The only parts of the license relevant to use are the disclaimers; the only reason a pure user of a GPL-ed program might want to read the license at all is to be informed that if the program causes loss of data (or whatever), the authors are not liable. GPLed programs get used all the time. A proprietary app on a GNU/Linux system can use the C library function system() which might invoke /bin/sh that is GNU Bash, and even depend on that functionality. > For example, if I buy a painting and cut it into pieces and rearrange them, I actually need an additional license beyond what I got from purchasing the copy. But what if that cut-up never leaves my house? Or what if I only distribute instructions which describe the geometry of some cuts which can be made to a painting, and the relocation of the pieces?
    - schoen 11y ago
      > But what if that cut-up never leaves my house? Maybe so, because the exclusive right is framed as a right "to prepare derivative works based upon the copyrighted work" (separate from reproduction, distribution, and other copyright rights). https://www.law.cornell.edu/uscode/text/17/106 https://www.law.cornell.edu/uscode/text/17/106
      - kazinator 11y ago
        Might it be that this separation between those rights exists so that the copyright holder can contract out manufacturing services, while controlling distribution? The copy house is given the right of preparing copies, without having distribution rights. I don't think I was infringing back in kindergarten when I cut up newspapers to make strips for papier-mâché. In any case, my courtroom argument there could be bolstered by the remark that the resulting work was painted, entirely concealing the original content.
dragonwriter 11y ago
The FSF takes the position that linking is derivative work; this may or may not be an accurate legal position, but it's a popular position from the licensed creator and an entity which owns a lot of software licenses under the GPL, and which is very influential with people who choose to use the GPL, so even if it is ultimately legally incorrect, the risk of litigation, whatever they outcome, from linking is going to be unacceptable to most significant users, so a GPL library is unlikely to see uptake in major software for which the creator had a significant reason for choosing a non-GPL license, whether it is permissive or proprietary.

kazinator 11y ago

I also believe this, but it is not an established fact. The GPL does prohibit it, and so whether that is actually enforceable has to be tested in a court of law. So you are in fact not free to do this, if you have a boss above you who cares dearly about the company steering clear of hot water. I'd be willing to testify as a technical expert in a court of law that the GPL cannot reasonably rule out dynamic linking; that dynamic linking to a program is a form of use (like invoking a command line and passing it arguments) and not integration. The proof is that dynamically linked components can be replaced by clean-room substitutes which work exactly alike, or at least well enough so that the main software can function. For example, a program can be shipped with a stub library which behaves like GNU Readline (but perhaps doesn't have all its features). The users themselves can replace that with a GNU Readline library. Thus, the program's vendor isn't even redistributing the GPL'ed component. They can provide it as a separate download or whatever. However, if they were to include a GNU Readline binary for the convenience of the users, then the program supposedly infringes. This is clearly nonsense.

belorn 11y ago
The problem with that line of thought is that the courts don't care if its use or integration, but if the resulting work depends on someone else work. The word used in copyright law is transform, adapt, recast, and such changes requires additional copyright permission. For example, if I buy a painting and cut it into pieces and rearrange them, I actually need an additional license beyond what I got from purchasing the copy. Components can not be cleanly viewed as separate when dealing with copyright. You can also turn this around and ask if its legal to use process call within a other program without invoking the need for additional permissions. FSF view that it should be legal, but it has never been tested. By now however an industry standard has formed around the FSF guidelines and most courts would just look at it when deciding. This is what commonly happen when no one go to court to find out what the rules actually should be.
- kazinator 11y ago
  > but if the resulting work depends on someone else work. Yes, so obviously your argument cannot be that "in theory, we could replace this with a workalike". You better have the workalike, and that's what you should be shipping. A powerful argument that you aren't infringing is that your shipping media are completely devoid of the work. > don't care if its use or integration For the sake of the GPL, they must care in this case, because the GPL specifically abstains from dictating use; it governs redistribution! The only parts of the license relevant to use are the disclaimers; the only reason a pure user of a GPL-ed program might want to read the license at all is to be informed that if the program causes loss of data (or whatever), the authors are not liable. GPLed programs get used all the time. A proprietary app on a GNU/Linux system can use the C library function system() which might invoke /bin/sh that is GNU Bash, and even depend on that functionality. > For example, if I buy a painting and cut it into pieces and rearrange them, I actually need an additional license beyond what I got from purchasing the copy. But what if that cut-up never leaves my house? Or what if I only distribute instructions which describe the geometry of some cuts which can be made to a painting, and the relocation of the pieces?
  - schoen 11y ago
    > But what if that cut-up never leaves my house? Maybe so, because the exclusive right is framed as a right "to prepare derivative works based upon the copyrighted work" (separate from reproduction, distribution, and other copyright rights). https://www.law.cornell.edu/uscode/text/17/106 https://www.law.cornell.edu/uscode/text/17/106
    - kazinator 11y ago
      Might it be that this separation between those rights exists so that the copyright holder can contract out manufacturing services, while controlling distribution? The copy house is given the right of preparing copies, without having distribution rights. I don't think I was infringing back in kindergarten when I cut up newspapers to make strips for papier-mâché. In any case, my courtroom argument there could be bolstered by the remark that the resulting work was painted, entirely concealing the original content.

dragonwriter 11y ago

The FSF takes the position that linking is derivative work; this may or may not be an accurate legal position, but it's a popular position from the licensed creator and an entity which owns a lot of software licenses under the GPL, and which is very influential with people who choose to use the GPL, so even if it is ultimately legally incorrect, the risk of litigation, whatever they outcome, from linking is going to be unacceptable to most significant users, so a GPL library is unlikely to see uptake in major software for which the creator had a significant reason for choosing a non-GPL license, whether it is permissive or proprietary.