[Qt] Release V.172RC

[Den Jean]

On Wednesday 23 September  2009 23:45:59 Felipe Monteiro de Carvalho wrote:
> On Wed, Sep 23, 2009 at 5:54 PM, Den Jean <Den.Jean at telenet.be> wrote:
> > and Qt 4.6 is almost out. Prepare for USE_QT_46 :-)

I just hinted that the USE_QT will remain necessary, see below

> Maybe it would be interresting to discuss our future policy for Qt
> version support. While it's a very good idea to go for Qt 4.5 and drop
> the previous ones to have a uniform license, I am in favor of stopping
> at Qt 4.5 for the years to come, because otherwise the Qt interface is
> useless in Linux. If the necessary Qt version isn't install will users
> need to build their own Qt to run LCL-Qt software? Is this really
> expected?

I think we need to support the current distributions and
prepare for the next ones. So that when the next ones
become available, lazarus/Qt can be installed.
Therefore, support Qt 4.5 and slowly prepare for Qt 4.6.

If you need an older distro (older than the current),
you can install a newer Qt alongside the distro wide one and 
use LD_LIBRARY_PATH.


But it might be nice if the makefile could detect the
qt version an define the correct USE_QT, so that
the users do not have to do anything.


eg. 
current = Mandriva 2009.1 = Qt 4.5
old = Mandriva 2009.0 (released in 2008) = Qt 4.4 
new = Mandriva 2010 (expected in Nov 2009) = Qt 4.5

This is comparable with Qt release dates:
Qt 4.0 June 28, 2005
Qt 4.1 December 19, 2005
Qt 4.2 October 4, 2006
Qt 4.3 May 30, 2007
Qt 4.4 May 6, 2008
Qt 4.5 March 3, 2009

Though the Trolls/Nokia generally do a good effort 
on not breaking compatibility, the problem with the fpc binding
is that a Qt 4.6 binding contains symbols that are not
resolved against a Qt 4.5 dll. Vice-versa a Qt 4.5 
binding can usually be used with a Qt 4.6. (Qt 4.4/4.5 
was a bad exception with the QFileDialog filter)


> In my experience they won't do it and if LCL-Gtk2 also expected
> everyone to have Gtk 2.18 or whatever high version it would also be
> useless in Linux and I think that LCL-Qt could have a shot at being
> the standard in some years if LCL-Qt programs can run in a large part
> of the installed Linux base, which will *never* happen if we keep
> upgrading without stop.
>
> So what do you think? Should we station Qt 4.5 or go upgrading with
> every new version?
prepare for Qt4.6 so that Qt 4.5 can be used with a Qt4.6.
See which classes will be deprecated/absent: 
http://doc.trolltech.com/4.6-snapshot/obsoleteclasses.html