Things to inlcude in an LGPL distribution

[The physicist]

Ok, puzzeled again. The v3.0 clearly says you need to provide a copy of the license. In v2.1 I don't find that term, but in the "how to apply" they write
Since the text is so small I would include it somewhere, just to be sure. But as always: Ask you lawyer if you have to

Oh, there's a v3.0 now is there!

To follow on from wysota, is the inclusion of the LGPL license soley for the distribution of the QT dlls with my program? And then, if I don't want to distribute my program under LGPL, I can just apply a copyright statement?and distribute it as is?

I shall try and seek legal advice anyway, and if I get a useful response, I shall let you all know...

[squidge]

I'd probably create a text file called 'licenses.txt' or similar and inside state something like:

'QtCore4.DLL, QtGUI4.DLL, ... <the entire list of DLLs you use from Qt>' are Copyright (C) 2011 Nokia. Used under license. See LGPL_License.txt for further information.'
'MyApp.EXE is Copyright (C) 2011 Me, and is licensed under the Beerware license. See Beerware.txt for further information'

Something like that should stop all ambiguity, but of course I'm no lawyer, so don't take this as legal advice.

[wysota]

Ok, puzzeled again. The v3.0 clearly says you need to provide a copy of the license. In v2.1 I don't find that term, but in the "how to apply" they write
Since the text is so small I would include it somewhere, just to be sure. But as always: Ask you lawyer if you have to

I always hate when someone uses the word "should" in a legal or otherwise formal document.

To follow on from wysota, is the inclusion of the LGPL license soley for the distribution of the QT dlls with my program?

Yes.

And then, if I don't want to distribute my program under LGPL, I can just apply a copyright statement?and distribute it as is?

We're not sure. You can dump a copy of LGPL (in English) somewhere in the archive just to be sure. It won't hurt.

I shall try and seek legal advice anyway, and if I get a useful response, I shall let you all know...

Just be aware that the number of interpretations of (L)GPL is more or less equal to the number of lawyers interpreting it.

[The physicist]

Thank you all for your help.

In practice, how does the dynamic linking actually work - If the dlls are updated, can the old ones simply be replaced with new ones, and the same executable will work with them?

[squidge]

If they are released as binary compatible (eg. minor versions), yes. There is no need to recompile or relink the application.

[wysota]

At least in theory

[The physicist]

Thanks again squidge and wysota.

Is there anything in the QT LGPL licensing that says it can't be used by companies/organisations? Or is it literally just for the distribution/modification of the libraries? I'm guessing you both have corporate licenses and don't have these problems

[Lykurg]

It is the LGPL, not the "Qt LGPL". So Qt can be used as any other library that is licensed under the GNU LGPL, to name it correctly. And the LGPL is just about how to use/modify it and does not say anything about who use it. So there is no limitation in that point.

[The physicist]

So, (in theory) my program should run with updated dlls.

In practice, how would someone relink my application without my source code if I supplied them the object files? This http://www.cis.temple.edu/~ingargio/cis71/ta/objectlib.html makes sense from a command line point of view, but I'm not sure how you would do it with QT

[Lykurg]

how would someone relink my application without my source code if I supplied them the object files?

By simply replacing the Qt dll's with his own/modified ones.

[The physicist]

By simply replacing the Qt dll's with his own/modified ones.

Oh, that simple

[squidge]

The object files would only be needed if you statically linked, then its upto them how to relink them to create a new executable. No one will bother, but at least you complied with the license by giving them the option.

Of course, object files are not necessary (even legally) for dynamically linked builds as you can just change the DLL.

[The physicist]

Thanks once again guys.

Not that I plan on moving to MS Visual Studio, but how does anyone know how the licensing works with applications developed with that? Is it the same as with the commercial license of QT?