lgpl license and commercial software..

[tgreaves]

Im a programmer, not a lawyer.. Whats the deal with the new lgpl license?

1. Can I create commercial(closed source) software and sell it using the lgpl version of Qt?
2. If I can sell it, Do I have provide the actual Qt toolkit source with it?

From what I have gathered, I can sell my closed source software but I have to include the sourcecode for the Qt toolkit its self and not the source for my program.. Sound right?

[ComaWhite]

You can sell software with LGPL. And no you don't have to give away the source. you can if you want. The only thing is you have to provide the dynamically link to the library no statically linked.

[radek.z]

Hi,
isn't it like that you can use Qt with your commercial software which can be source closed but you have to provide the source code for the Qt library you did?

[tgreaves]

You can sell software with LGPL. And no you don't have to give away the source. you can if you want. The only thing is you have to provide the dynamically link to the library no statically linked.

Understood..

Its dynamic linking where you use the dll's outside of your program and distribute them with your .exe program?

And static linking is where you compile the dll's into your .exe file.. Correct?

[Lykurg]

Its dynamic linking where you use the dll's outside of your program and distribute them with your .exe program?

And static linking is where you compile the dll's into your .exe file.. Correct?

Yes, and of course the dll have to be the original ones of Qt, no modified.

[tgreaves]

Awesome.. Do I have to put some agreement for installing my program that states that im using the lgpl license of Qt?

[krystosan]

Understood..

Its dynamic linking where you use the dll's outside of your program and distribute them with your .exe program?

And static linking is where you compile the dll's into your .exe file.. Correct?

this means the QT dlls I see in Autodesk Maya bin directory is becuase Autodesk uses LGPL ..How much does one has to pay under LGPL to digia to use QT ?

[Zlatomir]

@krystosan, LGPL is free so you don't have to pay anything to Digia, you just have the restrictions mentioned earlier, you have to pay only if you want the commercial license.

LE: and regarding sharing Qt source code you have to share it only if you modify Qt source code
Mainly those LGPL restrictions are "protecting" your clients in case you don't update your application with each Qt update, so they can do if themselves (or hire someone else to do it).

[amleto]

You can sell software with LGPL. And no you don't have to give away the source. you can if you want. The only thing is you have to provide the dynamically link to the library no statically linked.

This is not accurate. You can still statically link your application and satisfy LGPL. LGPL means that users of the software must be able to replace the Qt library with a different version. For statically linked applications this means that you will need to supply your .obj files - even in this case you would not need to include your source code.

[Lykurg]

this means the QT dlls I see in Autodesk Maya bin directory is becuase Autodesk uses LGPL

No, it does not. It only says that Autodesk uses shared libraries! This has nothing to do with the license. If they use LGPL they must notice that anywhere. If not, they have a commercial license or do not pay attention to the LGPL.

[anda_skoa]

It is always important to remember that selling (commerical aspect) and code license (legal aspect) are two orthogonal things.

Qt has many licensing options and none of them prohibit selling of applications.

The chosen license only affects the legal aspects, i.e. what license you can chose for your code, whether you have to notify the user about the library license, whether you have to ship or offer the code of the library, etc.

Cheers,
_