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I really like Qt and think its an incredible framework overall. Even if you don't use the Qt libraries, QtCreator is one of the best C++ IDEs out there imo (tho

I really like Qt and think its an incredible framework overall. Even if you don't use the Qt libraries, QtCreator is one of the best C++ IDEs out there imo (though qmake really sucks and they've been dragging their feet on a proper replacement for years) The real show stopper for me with Qt is its licensing though. LGPL is a no-go on closed mobile platforms and its commercial license at $350/month is completely unreasonable for smaller developers. Really, the LGPL is a horrible license because of its clause that you must be able to change out the LGPL portion of the software. Also almost every time there's a thread about Qt I see a bunch of (presumably) web developers start talking about React. In fact, in pretty much every thread talking about any similar framework someone has to mention React. I'm not a web developer and I've only looked at React briefly but I guess I just don't get it. Could someone explain succinctly what the big deal is? I've used Qt a lot -- what do all these people mentioning React want Qt to offer? Why is it brought up so often? Is it really that revolutionary? Almost seems like a cult.

CamperBob2 11y ago
Why not just put your proprietary stuff in a closed-source library and distribute the rest of the source in accordance with the LGPL? What's so horrible about that? Even iOS allows dynamic linking nowadays.
- twqtisgreatbut 11y ago
  The problem isn't dynamic linking, its the requirement that the end user must be able to re-link a modified version of the LGPL code. So for example, the user should be able to replace the Qt libraries your application links to. On closed platforms like iOS and Android (on Google Play) this isn't really possible. How would your user access your application, modify it and re-sign it?
  - shawn-butler 11y ago
    Previous discussion on HN of the mail app Sparrow and their approach in complying with LGPL on iOS: https://news.ycombinator.com/item?id=4302517 https://news.ycombinator.com/item?id=4302517 May be helpful to you.
    - twqtisgreatbut 11y ago
      Its not helpful, they aren't complying with the relinking clause. I don't think there's any way to use LGPL with closed source on mobile app stores.
      - shawn-butler 11y ago
        I'm assuming you didn't read it. I will give you benefit of the doubt since the Sparrow page was pulled after Google acquired them. Sparrow made available on a website the necessary binaries for the user to relink if they so chose thus complying with the terms of LGPL.
  - CamperBob2 11y ago
    Presumably your closed-source library has an API that you can document. This is how I handle some hardware-access DLLs for proprietary hardware; the distribution gives you the full source for the main program and the non-proprietary hardware access modules, plus the .DLL with the secret sauce for my own hardware. When you run the app, it loads all of the API-compliant DLLs and adds them to the device-selection menu. Anyone can build their own .DLL with the header files provided, or recompile the existing "open" ones if desired. For an iOS project, you'd provide a link to the GitHub/Sourceforge page or whatever. It's true that the end user would have to get a signing key from Apple to exercise their rights under the LGPL, but IMHO that still meets the spirit of the law. As far as I'm concerned my obligation ends when I provide the code. Some will disagree (hence GPLv3), but the same problem would exist if I had used a language (or targeted a platform) for which there were no free compilers, and nobody seems to have a problem there.

CamperBob2 11y ago

Why not just put your proprietary stuff in a closed-source library and distribute the rest of the source in accordance with the LGPL? What's so horrible about that? Even iOS allows dynamic linking nowadays.

twqtisgreatbut 11y ago
The problem isn't dynamic linking, its the requirement that the end user must be able to re-link a modified version of the LGPL code. So for example, the user should be able to replace the Qt libraries your application links to. On closed platforms like iOS and Android (on Google Play) this isn't really possible. How would your user access your application, modify it and re-sign it?
- shawn-butler 11y ago
  Previous discussion on HN of the mail app Sparrow and their approach in complying with LGPL on iOS: https://news.ycombinator.com/item?id=4302517 https://news.ycombinator.com/item?id=4302517 May be helpful to you.
  - twqtisgreatbut 11y ago
    Its not helpful, they aren't complying with the relinking clause. I don't think there's any way to use LGPL with closed source on mobile app stores.
    - shawn-butler 11y ago
      I'm assuming you didn't read it. I will give you benefit of the doubt since the Sparrow page was pulled after Google acquired them. Sparrow made available on a website the necessary binaries for the user to relink if they so chose thus complying with the terms of LGPL.
- CamperBob2 11y ago
  Presumably your closed-source library has an API that you can document. This is how I handle some hardware-access DLLs for proprietary hardware; the distribution gives you the full source for the main program and the non-proprietary hardware access modules, plus the .DLL with the secret sauce for my own hardware. When you run the app, it loads all of the API-compliant DLLs and adds them to the device-selection menu. Anyone can build their own .DLL with the header files provided, or recompile the existing "open" ones if desired. For an iOS project, you'd provide a link to the GitHub/Sourceforge page or whatever. It's true that the end user would have to get a signing key from Apple to exercise their rights under the LGPL, but IMHO that still meets the spirit of the law. As far as I'm concerned my obligation ends when I provide the code. Some will disagree (hence GPLv3), but the same problem would exist if I had used a language (or targeted a platform) for which there were no free compilers, and nobody seems to have a problem there.