[joezydeco]

The LGPL thing is not really the issue here. It's how Trolltech/Nokia/Digia/QtCo approached the payment of a commercial license.

It's always been explained to me by the sales people that "you cannot switch licensing models mid-stream". So if you're planning to go commercial, you start commercial.

It's not really about closing the deal as much as making sure the Trolltech developers were paid during the time you needed their support.

[loeg]

> It's not really about closing the deal as much as making sure the Trolltech developers were paid during the time you needed their support.

The OSS license doesn't grant you any support from Trolltech, does it?

[joezydeco]

Of course not. But I could totally see Trolltech getting critical bugfix requests from people "promising" to pay the commercial license once they launch.

I would totally understand the response eventually turning into "yeah, we'll fix your bug, but put your money where your mouth is", which is where they are today.

[Grishnakh]

But do you even need a commercial license to sell your product commercially? It's LGPL, so surely you can just keep the Qt library LGPL. If you're not changing anything at all in Qt (and you really shouldn't be...), and you don't care about getting support (the docs are good enough for you), then why do you need a commercial license at all?

[distances]

There are still some cases where you need a license, like Qt for Device Creation (https://www.qt.io/qt-for-device-creation). Or perhaps you need static linking, or want to include some Qt code in the app proper for one reason or another.

[Grishnakh]

Ok, but if you stick with dynamic linking and don't insert Qt code into your app, then you don't need a commercial license, right? Why would you insert Qt code in your app anyway? That kinda defeats the point of using a library. As for static linking, why would you opt for this over dynamic linking anyway? Dynamic linking is better since other applications can share the libraries. Static linking on a PC platform is basically a hack for poor library management.

As for Qt for Device Creation, I looked through that and didn't see why you'd need a license there, unless they're selling optional components or plug-ins which are not LGPL licensed (which appears to be the case with things like "Qt Quick 2D Renderer" and "Qt Virtual Keyboard").

I even tried out the questionnaire at www.qt.io/download: if you select "Commercial deployment" for development and then say that you're doing dynamic linking, don't have any concerns about reverse-engineering, and can comply with the LGPL, it recommends you use the open-source LGPL'ed version.

[distances]

Just listing some possibilities, different projects have different needs. Sure, for most of the cases the dynamically linked open source version works just fine.

Qt for Device Creation needs a license, that one is not available as LGPL. Of course you can use the open source Qt yourself for that, but then you'll be facing a lot of platform work to get Qt running on your device before even starting with the stuff that you actually want to build.

[kevin_thibedeau]

You can statically link LGPL. Your only obligation is to provide object files so that customers can relink.