Re: GUI design

[Michael Goffioul]

On Thu, Mar 29, 2012 at 7:54 PM, Daniel J Sebald <address@hidden> wrote:
> On 03/29/2012 01:45 PM, Michael Goffioul wrote:
>>
>> On Thu, Mar 29, 2012 at 6:26 PM, Daniel J Sebald<address@hidden>
>>  wrote:
>>>
>>> On 03/28/2012 11:49 PM, Daniel J Sebald wrote:
>>>
>>> [snip]
>>>
>>>> It sounds like developers have looked at the GUI development tools
>>>> enough to conclude that Qt provides the power and flexibility for future
>>>> growth of an IDE. Correct?
>>>
>>>
>>>
>>> The Qt license appears to be the GNU "lesser" GPL.  Have people thought
>>> through whether that is suitable for Octave's normal GNU GPL?
>>
>>
>> This is not true. Qt is distributed under GPLv3, LGPL v2 or commercial
>> license. See http://qt.nokia.com/downloads/downloads#qt-lib
>
>
> The L of LGPL stands for "lesser".  I'm not sure what the difference is
> between the LGPL license and the GPL license, but apparently they are
> different:

Basically, LGPL allows you to distribute software linked against the
LGPL component in binary-only format. So you can build closed-source
software on LGPL, which is not possible with GPL. Many GNU libraries
are distributed under LGPL, while the executables are covered by GPL.
Qt used to be GPL or commercial-only [1], which meant you could only
build closed-source products by buying a Qt license, which was/is
quite expensive. When Trolltech was bought by Nokia, one of the first
change was to add LGPL license (I think the idea at that time was at
least partially to foster development of applications for Nokia
phones).

Michael.

[1] There used to be also a GPL exception for KDE libraries, in the
form of QPL; this was made obsolete when Qt got licensed under LGPL.