On 2/19/07, Den Jean <[EMAIL PROTECTED]> wrote:
Not really, for GPL bindings like PerlQt, PyQt etc
and thus also for Qt4 for FPC you can develop
commercial programs,
Actually, this does not contradict what I have to say.
The point is: I know one can develop new software with bindings, but
what about old software? Like taking a existing lazarus software and
recompiling with the Qt interface.
There are several restrictions to be considered. I am not talking
about the GPL restrictions. I am talking about the restrictions on the
proprietary Qt license. I will quote the faq to be more clear:
"Entry number: 182 - Can we use the Open Source Edition while
developing our non-opensource application and then purchase commercial
licenses when we start to sell it?
Answer:
No. Our commercial license agreements only apply to software that was
developed with Qt under the commercial license agreement. They do not
apply to code that was developed with the Qt Open Source Edition prior
to the agreement. Any software developed with Qt without a commercial
license agreement must be released as Open Source software. "
I just did that. I developed lcl-qt interface without a qt commercial
license, so according to the FAQ, this can never be used with Qt's
proprietary license. This is not a restriction on the GPL version of
Qt. This is a restriction on the proprietary version of Qt. Except if
I contact Trolltech and they agree otherwise, of course.
Actually, if I am correct, the bindings source code also cannot be
used with Qt proprietary license.
My guess about Python bindings is either that they are only developed
by people that own Qt licenses, or that trolltech allowed them to use
old code with the commercial license.
Also, another interresting issue arrises. If only one person with a
commercial Qt license write a pascal binding, writes a LCL interface,
and then distributes the library, as I understood it, everyone else
can use that proprietary library without a Qt license, unless there is
more in the Qt proprietary license that forbits it.
Because on Qt you pay for the development, and here you are not really
using Qt to develop anything. You are using LCL, which just happens to
use Qt. Again, there may be additional restrictions that forbit that.
--
Felipe Monteiro de Carvalho
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