4 ms·

Can this dynamically link to Qt to circumvent the GPL?

• orra 5y ago
  Dynamic linking doesn't circumvent copyright law, so it doesn't circumvent copyleft.
  • Macha 5y ago
    To some extent the intent of the author matters, and in their "Just buy a license" pitch[1], the Qt company implicitly threatens lawsuits for GPL violations _if_ you use the open source version and fail to provide an adequate means to switch out the linked binaries. So the people who could enforce a copyright claim are drawing that distinction, which means it does matter here. In addition, they mix licenses between GPL and LGPL, so failing to take proper care means you could be relying on a GPL module and think you're ok by complying with the LGPL. [1]: https://www.qt.io/licensing/open-source-lgpl-obligations https://www.qt.io/licensing/open-source-lgpl-obligations
    • isomel 5y ago
      It's like asking "do you accept bitcoin to circumvent tax law" First of all, bitcoin does not circonvent tax law. (And linking does not circonvent GPL)
    • orra 5y ago
      You can meet a major LGPL requirement by dynamically linking your dependencies or by providing object files that the user can statically relink. Neither is circumventing the LGPL, however. I take your point the Qt company wants (L)GPL licensing to sound scary, so they can sell licenses.
• oever 5y ago
  Qt is LGPL 3.0. Dynamically linking from close source is allowed.
  • Macha 5y ago
    Some of QT is LGPL, other parts are GPL. The question about dynamic linking is valid, since Rust's build system, Cargo, produces a static binary by default.
    • ogoffart 5y ago
      Cargo links all the rust code together in a static binary, but the C/C++ libraries can be linked dynamically, and in the case of something like Qt, most certainly are. Since most important part of Qt are LGPL, you can use this crate and other Qt binding crates to develop proprietary applications. (Only if you wish to use one of the few parts that are "only" GPL, then you need to release the final product and all its parts under the GPL, or acquire a Qt license)
      • 3836293648 5y ago
        You can even link rust to rust dynamically, though it's very unsafe and will break if you use different compiler versions