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I've never understood the problem with (L)GPL code on iOS devices. Sure, users don't have the possibility to replace the code on that platform. But the restrict

I've never understood the problem with (L)GPL code on iOS devices. Sure, users don't have the possibility to replace the code on that platform. But the restriction is not imposed by the people distributing the code, but by external circumstances (Apple). I can distribute LGPL licensed code to people no problem even if they are then, additionally, forbidden to actually excercise their freedoms by laws, think for example about radio code. I might have to get a special permission to run the code if I make changes and compile it, but that's no concern of the person licensing their source code to me. Same if, say, the code runs on a box in an inaccessible space, and in order to install their own binaries somebody would have to press a button that they can't reach. That's not a GPL violation. If I have the OK from Tim Cook and all the secret signing keys, I can compile and run anything I want on my iOS device. And even without that, if somebody provides all the object files of non-LGPL code and build instructions, I can replace the LGPL code and run my own version outside of the app store. Often when people ban (L)GPL code, its just a pretext, because they don't want to deal with the complexities or for other reasons. Edit: I've been thinking about LGPL 2.1. I think LGPL 3 does explicitly forbid the above mentioned situations? (And of course this is just my reading as an interested layperson, you're the expert obviously :-))

ffgjgf1 3y ago
> I've never understood the problem with (L)GPL code on iOS devices AFAIK Apple just doesn’t allow apps which don’t that on the app store regardless of how the developer would chose to interpret the license
- wahnfrieden 3y ago
  that's outdated info
  - BizarroLand 3y ago
    Your face is on backwards if you think it's acceptable to tell someone that their information is outdated without also providing the new and up to date information.
    - beeboobaa 3y ago
      It's Apple's App Store. Being vague and non committal is how they roll.
    - deleted 3y ago
      [deleted]
    - yreg 3y ago
      https://developer.apple.com/forums/thread/27709 https://developer.apple.com/forums/thread/27709 https://stackoverflow.com/questions/35068054/does-app-store-accept-qt-app-linked-with-qt-library-lgplv3 https://stackoverflow.com/questions/35068054/does-app-store-...
mort96 3y ago
Let's imagine I'm making MortPlayer, a video player for iOS which uses a version of the VLC libraries which are licensed under LGPL 2.1 (since that's what you're focusing on). Let's say I want MortPlayer to be closed source. In other words, VLC owns the libraries, and I want to license them under the LGPL 2.1. The LGPL 2.1 says: 6. As an exception to the Sections above, you may also combine or link a "work that uses the Library" with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modification of the work for the customer's own use and reverse engineering for debugging such modifications. Okay, so I must distribute MortPlayer under terms which permit modification and reverse engineering. I can do that. Maybe Apple's terms conflict, but let's assume that's not an issue, let's read on. You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License. If the work during execution displays copyright notices, you must include the copyright notice for the Library among them, as well as a reference directing the user to the copy of this License. Okay, no problem. Also, you must do one of these things: Oh boy. a) Accompany the work with the complete corresponding machine-readable source code for the Library including whatever changes were used in the work (which must be distributed under Sections 1 and 2 above); and, if the work is an executable linked with the Library, with the complete machine-readable "work that uses the Library", as object code and/or source code, so that the user can modify the Library and then relink to produce a modified executable containing the modified Library. (It is understood that the user who changes the contents of definitions files in the Library will not necessarily be able to recompile the application to use the modified definitions.) Okay. I can accompany the work (MortPlayer) with the source code for VLC's libraries, no problem. MortPlayer is executed and linked with VLC's libraries, so I need to 'accompany the work with ... the complete machine-readable "work that uses the Library", as object code and/or source code, so that the user can modify the Library and then relink to produce a modified executable containing the modified Library". I think that's doable with app stores? I can certainly distribute a zip file with the object files for MortPlayer so that the user can link them against their own version of VLC. The user wouldn't be able to then run the recompiled application, on their device, but that's not specified in the terms... Honestly I'm a bit surprised, I fully expected to find that this section a) included wording which requires the user to be able to run the resulting linked application, which Apple forbids (asterisk), and then go through b) and conclude that iOS doesn't have a "suitable shared library mechanism" due to its restrictions etc. But I'm instead forced to conclude that you're probably right, at least by the letter of the license. I read the corresponding parts of LGPL 3 as well, and I can't find anything which requires the re-linked application to be immediately executable on the user's machine there either. I think my conclusion is that LGPL, both 2.1 and 3.0, is fully compatible with app stores so long as you distribute your application as object code which can be linked against the LGPL licensed libraries? I would be very interested to hear from someone with opposing views about why I may be wrong. I, as they say, ANAL.
ajross 3y ago
> I've never understood the problem with (L)GPL code on iOS devices. Sure, users don't have the possibility to replace the code on that platform. But the restriction is not imposed by the people distributing the code, but by external circumstances (Apple). That seems very forest-for-the-trees. It's true, but it mistakes a micro-statement of a problem (the app vendor isn't "at fault" for the LGPL violation) with the actual problem (copyleft code of any kind is effectively impossible on the most popular mobile platform in the industrial world). The bottom line is that it's not possible to distribute a binary containing *GPL code on iOS in any way remotely in keeping with the letter of the license. People do it anyway because this code is important and useful. But Apple has effectively banned the license and that's always going to lead to friction like this.
- torstenvl 3y ago
  > it's not possible to distribute a binary containing *GPL code on iOS in any way remotely in keeping with the letter of the license. That is quite audacious to claim. Do you have a citation to any case law supporting your position? If not, what would be your argument?
  - ajross 3y ago
    It's in the text of the license? See section 6. a) https://www.gnu.org/licenses/old-licenses/lgpl-2.0.en.html https://www.gnu.org/licenses/old-licenses/lgpl-2.0.en.html Also of course section 9: "You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Library or its derivative works. These actions are prohibited by law if you do not accept this License." You can't legally put copyleft stuff on the App store, because the recipient can't modify the results. That we've all as a society decided to look the other way doesn't change the requirements of the license.
    - torstenvl 3y ago
      So no case law. You've pointed me to two sections of the license, but neither directly says what you're claiming. Why don't you help us understand what your argument would be? I.e., explain how you would apply the rules in the license to the facts of iOS distribution to reach the conclusion that distribution on iOS is a per se violation?
fragmede 3y ago
Within limits, all it takes to get the OK from Tim Cook is $99/yr to the Apple Developer Program. Which isn't $0, but the LGPL doesn't say someone else can't charge money to press the button. You don't get arbitrary code execution for those $99, but you get enough access to playback video. You'd have to create your own app and get it blessed by Apple in order to distribute it to other people, but doesn't that satisfy the letter of the law here? As a 3rd party developer with my own developer account, I can get the source and the object code and run my own binary that links against it on the same platform, iOS.
kelnos 3y ago
> I've never understood the problem with (L)GPL code on iOS devices. Sure, users don't have the possibility to replace the code on that platform. But the restriction is not imposed by the people distributing the code, but by external circumstances (Apple). In the case of the App Store, Apple is the one doing distribution, so Apple must also comply with the terms of the license (in addition to the app developer). Apple has decided they will not do that (that is, people they distribute to will not have the ability to modify the LGPL code, relink the final executable, and run it on their devices), so Apple cannot legally distribute binaries that contain LGPL code. It only makes sense, then, that Apple should preemptively reject apps that link in LGPL code, as they know that they will not abide by the licensing terms. > If I have the OK from Tim Cook and all the secret signing keys, I can compile and run anything I want on my iOS device. And even without that, if somebody provides all the object files of non-LGPL code and build instructions, I can replace the LGPL code and run my own version outside of the app store. That's not permitted by the license. The (L)GPL prohibits a third party from adding extra conditions to exercising the rights granted in the license. "Pay Apple for a developer account and get their permission" is an extra condition. Even if there is a jailbreak-y method of getting around the extra conditions, I don't think that would fly. > Often when people ban (L)GPL code, its just a pretext, because they don't want to deal with the complexities or for other reasons. Agreed, but I'm not convinced this is one of those cases.
- foota 3y ago
  Does LGPL require that you be able to do so on the same platform it's being distributed on? There's nothing stopping someone from downloading an LGPL binary from the app store and running it in an emulator or something, right?
  - cyphar 3y ago
    In short, yes. See 4(e): > Provide Installation Information, but only if you would otherwise be required to provide such information under section 6 of the GNU GPL, and only to the extent that such information is necessary to install and execute a modified version of the Combined Work produced by recombining or relinking the Application with a modified version of the Linked Version. And from GPLv2: > For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable.
rufwork 3y ago
This discussion has reminded me why I stopped using LGPL and started using MPL for libs. OWN THE LIBS… I mean share them. Share the libraries.

ffgjgf1 3y ago

> I've never understood the problem with (L)GPL code on iOS devices AFAIK Apple just doesn’t allow apps which don’t that on the app store regardless of how the developer would chose to interpret the license

wahnfrieden 3y ago
that's outdated info
- BizarroLand 3y ago
  Your face is on backwards if you think it's acceptable to tell someone that their information is outdated without also providing the new and up to date information.
  - beeboobaa 3y ago
    It's Apple's App Store. Being vague and non committal is how they roll.
  - deleted 3y ago
    [deleted]
  - yreg 3y ago
    https://developer.apple.com/forums/thread/27709 https://developer.apple.com/forums/thread/27709 https://stackoverflow.com/questions/35068054/does-app-store-accept-qt-app-linked-with-qt-library-lgplv3 https://stackoverflow.com/questions/35068054/does-app-store-...

mort96 3y ago

Let's imagine I'm making MortPlayer, a video player for iOS which uses a version of the VLC libraries which are licensed under LGPL 2.1 (since that's what you're focusing on). Let's say I want MortPlayer to be closed source. In other words, VLC owns the libraries, and I want to license them under the LGPL 2.1. The LGPL 2.1 says: 6. As an exception to the Sections above, you may also combine or link a "work that uses the Library" with the Library to produce a work containing portions of the Library, and distribute that work under terms of your choice, provided that the terms permit modification of the work for the customer's own use and reverse engineering for debugging such modifications. Okay, so I must distribute MortPlayer under terms which permit modification and reverse engineering. I can do that. Maybe Apple's terms conflict, but let's assume that's not an issue, let's read on. You must give prominent notice with each copy of the work that the Library is used in it and that the Library and its use are covered by this License. You must supply a copy of this License. If the work during execution displays copyright notices, you must include the copyright notice for the Library among them, as well as a reference directing the user to the copy of this License. Okay, no problem. Also, you must do one of these things: Oh boy. a) Accompany the work with the complete corresponding machine-readable source code for the Library including whatever changes were used in the work (which must be distributed under Sections 1 and 2 above); and, if the work is an executable linked with the Library, with the complete machine-readable "work that uses the Library", as object code and/or source code, so that the user can modify the Library and then relink to produce a modified executable containing the modified Library. (It is understood that the user who changes the contents of definitions files in the Library will not necessarily be able to recompile the application to use the modified definitions.) Okay. I can accompany the work (MortPlayer) with the source code for VLC's libraries, no problem. MortPlayer is executed and linked with VLC's libraries, so I need to 'accompany the work with ... the complete machine-readable "work that uses the Library", as object code and/or source code, so that the user can modify the Library and then relink to produce a modified executable containing the modified Library". I think that's doable with app stores? I can certainly distribute a zip file with the object files for MortPlayer so that the user can link them against their own version of VLC. The user wouldn't be able to then run the recompiled application, on their device, but that's not specified in the terms... Honestly I'm a bit surprised, I fully expected to find that this section a) included wording which requires the user to be able to run the resulting linked application, which Apple forbids (asterisk), and then go through b) and conclude that iOS doesn't have a "suitable shared library mechanism" due to its restrictions etc. But I'm instead forced to conclude that you're probably right, at least by the letter of the license. I read the corresponding parts of LGPL 3 as well, and I can't find anything which requires the re-linked application to be immediately executable on the user's machine there either. I think my conclusion is that LGPL, both 2.1 and 3.0, is fully compatible with app stores so long as you distribute your application as object code which can be linked against the LGPL licensed libraries? I would be very interested to hear from someone with opposing views about why I may be wrong. I, as they say, ANAL.

ajross 3y ago

torstenvl 3y ago
> it's not possible to distribute a binary containing *GPL code on iOS in any way remotely in keeping with the letter of the license. That is quite audacious to claim. Do you have a citation to any case law supporting your position? If not, what would be your argument?
- ajross 3y ago
  It's in the text of the license? See section 6. a) https://www.gnu.org/licenses/old-licenses/lgpl-2.0.en.html https://www.gnu.org/licenses/old-licenses/lgpl-2.0.en.html Also of course section 9: "You are not required to accept this License, since you have not signed it. However, nothing else grants you permission to modify or distribute the Library or its derivative works. These actions are prohibited by law if you do not accept this License." You can't legally put copyleft stuff on the App store, because the recipient can't modify the results. That we've all as a society decided to look the other way doesn't change the requirements of the license.
  - torstenvl 3y ago
    So no case law. You've pointed me to two sections of the license, but neither directly says what you're claiming. Why don't you help us understand what your argument would be? I.e., explain how you would apply the rules in the license to the facts of iOS distribution to reach the conclusion that distribution on iOS is a per se violation?

fragmede 3y ago

Within limits, all it takes to get the OK from Tim Cook is $99/yr to the Apple Developer Program. Which isn't $0, but the LGPL doesn't say someone else can't charge money to press the button. You don't get arbitrary code execution for those $99, but you get enough access to playback video. You'd have to create your own app and get it blessed by Apple in order to distribute it to other people, but doesn't that satisfy the letter of the law here? As a 3rd party developer with my own developer account, I can get the source and the object code and run my own binary that links against it on the same platform, iOS.

kelnos 3y ago

> I've never understood the problem with (L)GPL code on iOS devices. Sure, users don't have the possibility to replace the code on that platform. But the restriction is not imposed by the people distributing the code, but by external circumstances (Apple). In the case of the App Store, Apple is the one doing distribution, so Apple must also comply with the terms of the license (in addition to the app developer). Apple has decided they will not do that (that is, people they distribute to will not have the ability to modify the LGPL code, relink the final executable, and run it on their devices), so Apple cannot legally distribute binaries that contain LGPL code. It only makes sense, then, that Apple should preemptively reject apps that link in LGPL code, as they know that they will not abide by the licensing terms. > If I have the OK from Tim Cook and all the secret signing keys, I can compile and run anything I want on my iOS device. And even without that, if somebody provides all the object files of non-LGPL code and build instructions, I can replace the LGPL code and run my own version outside of the app store. That's not permitted by the license. The (L)GPL prohibits a third party from adding extra conditions to exercising the rights granted in the license. "Pay Apple for a developer account and get their permission" is an extra condition. Even if there is a jailbreak-y method of getting around the extra conditions, I don't think that would fly. > Often when people ban (L)GPL code, its just a pretext, because they don't want to deal with the complexities or for other reasons. Agreed, but I'm not convinced this is one of those cases.

foota 3y ago
Does LGPL require that you be able to do so on the same platform it's being distributed on? There's nothing stopping someone from downloading an LGPL binary from the app store and running it in an emulator or something, right?
- cyphar 3y ago
  In short, yes. See 4(e): > Provide Installation Information, but only if you would otherwise be required to provide such information under section 6 of the GNU GPL, and only to the extent that such information is necessary to install and execute a modified version of the Combined Work produced by recombining or relinking the Application with a modified version of the Linked Version. And from GPLv2: > For an executable work, complete source code means all the source code for all modules it contains, plus any associated interface definition files, plus the scripts used to control compilation and installation of the executable.

rufwork 3y ago

This discussion has reminded me why I stopped using LGPL and started using MPL for libs. OWN THE LIBS… I mean share them. Share the libraries.