Publishing Qt Software commercially

[bmn]

Hey, sorry if im offtopic, but dont know where else to post it?

I'm writing a little project about Qt, and find myself lost in the Qt licens jungle :)

If a person were to write a piece of logistics software to a company (say, one were writing a tracking software to Ford Motors or whatever), what licens would i have to choose, and what would it cost?

Sorry if this is a simple question, but i just really want to get it right :)

[wysota]

You can publish your software at a licence of your choice and use Qt on LGPL. Just make sure your licence doesn't violate Qt's LGPL licence.

[jackmack]

Hi,
I have had the same question ;-)
There are two licences, LGPL and commercial.

Commercial:
You have to buy Qt framework, ask Trolltech to make a good price to you. This includes proffesional support by Trolltech and you can distribute your software based on Qt for money. Nobody has the right to get your source code. You can use Qt dynamically or static linked. What you want.

LGPL:
That means you can distribute your software based on Qt also for money. But with the diffrent of using Qt:

Dynamically linked Qt:
Means you get money for your software and noboday has the right to get your source code. If you have made changes to Qts source code (like bug fixes, optimizing e.g.) then you have to inform Trolltech AND if you customer wants to get these changes you have to give him that (only Qt source code, NOT your source code!).

Static linked Qt:
The same as dynamically linked but with the diffrent: If somebody wants the source code you have to give him the complete sources (yours and Qts).

You wonder why Trolltech supports the LGPL and gives the Qt framework for less?
I think they want that many programmers uses the Qt framework to develop software for PCs, SmartPhones (Nokia) e.g.

Hope this helps and hope I understood the LGPL correct. ;-)

[nightghost]

Uhh, license questions :) But interesting point. Is the difference between static and dynamic usage of the LGPL library really true?

[wysota]

Uhh, license questions :) But interesting point. Is the difference between static and dynamic usage of the LGPL library really true?

It's a "close enough" simplification of the licence restrictions.

[marcvanriet]

You wonder why Trolltech supports the LGPL and gives the Qt framework for less?
I think they want that many programmers uses the Qt framework to develop software for PCs, SmartPhones (Nokia) e.g.

I think I read that when Nokia took over Trolltech, they were interested in the technology (Qt framework) but not the commercial activities of Trolltech, so they opened it up (meaning also visual studio version freely available on Windows, and previously closed libraries now also available to anyone). But of course you can't give customer support for free, so customers must still pay for this.

Regards,
Marc