QT and the LGPL

Well, I kind of thought this might happen when Nokia bought them....starting with version 4.5 QT will be licensed under the LGPL (or commercial license if you can't deal with the LGPL stipulations)

Thought it might be of interest to a few around here!

Edit: Whoopsie, title wrong!

One of these days I'm going to have to get my head round the whole licensing thing...

Hmm, I think that's likely to be a good thing overall. It's the appropriate license for a library; the GPL is really more appropriate for applications.

It allows commercial users to get into opensource without having to pre-decide to make their own product OSS.
It should boost appeal on Windows - though I suspect that ship sailed a while back; the niche would be for those considering multi-platform support.

Is there a difference today that wasn't there even 4 or 5 years ago? The main difference I see after visiting their site is that it's impossible to see how much Qt actually costs now.

It's still listed as a commercial product when undertaking commercial development, requiring a license PER developer. If I'm not mistaken, this used to be around $6000 per developer for cross-platform deployment (Windows, Mac OS and Linux).

Another difference I see is that they have some ambiguous language about charging you even more if the UI of your application is controlled by Qt. Whatever that means.

That option hasn't changed. But for those companies who are happy releasing software under the terms of the LGPL, but not the GPL -- which, for instance, would almost certainly have included Empeg when initially considering writing Emplode -- there's now an alternative option.

This announcement by Nokia/Trolltech basically means that WxWindows is dead, GNOME is dying, and Win32 itself has gone to see its doctor about a persistent cough. Unless you're developing a Windows application that there couldn't, even in theory, be a Mac version of (maybe it's domain-related or something) -- or a Mac application that there couldn't, even in theory, be a Windows version of -- then Qt has got to be at the top of your list of frameworks to consider writing for.

Although they probably do need, once Qt 4.5 comes out, to get rid of the thing that says that people using Qt under the commercial licence, can't use code that was written against any of the open-source licences. The effect of that stipulation, is that if I write some code against Qt and release it into the public domain, then people writing either PD, BSD, or commercial software can use it if they remove the Qt dependencies, and people writing GPL or LGPL software can use it with their licensed Qt -- the only people in the world who can't use it are people with commercial Qt licences. That would seem a bit nutty.

Peter

Most developers I know would still prefer to develop natively for their target platforms. This was the issue when I looked into Qt long ago. Just too many licensing and other headaches no one wanted to deal with for software to be included as part of a commercial release. Even though it was the best cross-platform kit I found at the time (and likely still is). Incidentally, I was proponent of using Qt for the projects I was investigating it for.

I don't think this is going to reduce in any way the number of native Win32 or Mac OS (Carbon or Cocoa) apps we see going forward.

While I've never written any truly commercial software, Qt is without a doubt my favourite framework. In my previous job we had to write all our win32 apps using the native API, now Mr. Petzold did his best, but doing anything with it made me want to beat my head against a brick wall. Similarly I tried recently to get my head round Cocoa and found it very difficult to pick up.

Qt on the other hand 'just makes sense' to me. I get access to all sorts of libraries across so many different areas. I write code on my MBP at home and it compiles on the Windows and linux boxes at work. I'm sure if you want 100% integration with host OS or really whizzy performance then you probably need to go native. But that's never been an issue for me.