[gentoo-user] QT 4

[gentoo-user] QT 4

[James]

Hello,

Has anyone any experiences with developing software with QT4?

checking whats available, with 'emerge -pv qt', I see: 
x11-libs/qt-3.3.4-r8

Nothing else... If I add x11-libs/qt to the package.keywords
file, I get 
x11-libs/qt-4.1.1

after editing the package.keyword file, If I run emerge -uDp world,
it want to upgrade qt:
Calculating world dependencies ...done!
[ebuild     U ] x11-libs/qt-3.3.4-r9 [3.3.4-r8]

I really confused as this is not very clear what the hardmasked, testing
and stable versions of QT........?

I've been told that QT 4 is 'very young' which I interpret as unstable
and buggy. How do I tell if qt-4.1.1 is hard masked or testing....
as I've never seen this before.


Should I avoid qt4 or is it OK for use, it's just testing on Gentoo?


Any feedback is appreciated,

James



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Re: [gentoo-user] QT 4

[Dmitry S. Makovey]

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On Thursday 16 March 2006 12:11, James wrote:
> Hello,
>
> Has anyone any experiences with developing software with QT4?
>
> checking whats available, with 'emerge -pv qt', I see:
> x11-libs/qt-3.3.4-r8
>
> Nothing else... If I add x11-libs/qt to the package.keywords
> file, I get
> x11-libs/qt-4.1.1
>
> after editing the package.keyword file, If I run emerge -uDp world,
> it want to upgrade qt:
> Calculating world dependencies ...done!
> [ebuild     U ] x11-libs/qt-3.3.4-r9 [3.3.4-r8]

since packages you use (I assume KDE etc.) are not using qt4 (i.e. 
require specifically qt3 branch) portage doesn't find any reasons to 
bump version of qt. AFAIR Qt is a slotted package and you can safely 
go ahead and do 
emerge =x11-libs/qt-4.1.1 
but you packages wouldn't use it.

-- 
Dmitry Makovey
Web Systems Administrator
Athabasca University
(780) 675-6245

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[gentoo-user] Re: QT 4

[James]

Dmitry S. Makovey <dmitry <at> athabascau.ca> writes:

> since packages you use (I assume KDE etc.) are not using qt4 (i.e. 
> require specifically qt3 branch) portage doesn't find any reasons to 
> bump version of qt. AFAIR Qt is a slotted package and you can safely 
> go ahead and do 
> emerge =x11-libs/qt-4.1.1 
> but you packages wouldn't use it.
 
Ok this kinda makes sense. But what exactly is a 'slotted package',
how do I determine when a packages is slotted, and where do I read
more about 'slotted'? I see this term used ofen, but, really have
no clue exactly what slotted means or if it has various meanings
based on the context of it's (verbiage) usage.

I'm looking at participating in developing software for remote control
of hardware, SCADA, if that means anything to you. One of the guys is
raving about QT4, so I need to install it, write a little code
and play with it to form an opinion related to it's viability as
a basis for open source SCADA development. Java is very nice, but
many folks do not like JAVA, due to licenses issues......

Hence the interest in QT4.

James






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Re: [gentoo-user] Re: QT 4

[Shawn Haggett]

James wrote:
> Dmitry S. Makovey <dmitry <at> athabascau.ca> writes:
> 
>> since packages you use (I assume KDE etc.) are not using qt4 (i.e. 
>> require specifically qt3 branch) portage doesn't find any reasons to 
>> bump version of qt. AFAIR Qt is a slotted package and you can safely 
>> go ahead and do 
>> emerge =x11-libs/qt-4.1.1 
>> but you packages wouldn't use it.
>  
> Ok this kinda makes sense. But what exactly is a 'slotted package',
> how do I determine when a packages is slotted, and where do I read
> more about 'slotted'? I see this term used ofen, but, really have
> no clue exactly what slotted means or if it has various meanings
> based on the context of it's (verbiage) usage.

Slotted means you can have several different versions of a package
installed, *at the same time*. So in this case it would mean you would
end up with qt-3.x still installed and qt-4.x also installed. Since KDE
would be linked against 3.x, it would continue to use that, while you
could in theory link against the 4.x version.

James wrote:
> checking whats available, with 'emerge -pv qt', I see:
> x11-libs/qt-3.3.4-r8
>
> Nothing else... If I add x11-libs/qt to the package.keywords
> file, I get
> x11-libs/qt-4.1.1
>
> after editing the package.keyword file, If I run emerge -uDp world,
> it want to upgrade qt:
> Calculating world dependencies ...done!
> [ebuild     U ] x11-libs/qt-3.3.4-r9 [3.3.4-r8]

If you go to http://packages.gentoo.org/search/?sstring=qt;offset=40 you
can see all the versions of qt (third one down on the page). 'emerge -pv
qt' first off shows you the latest stable version, 3.3.2-r8. When you
add qt to your package.keywords file though, emerge -pv qt' will want to
install the *latest* version of qt that is available, currently 4.1.1.
However the update world command will find that KDE specifically
requires 3.x, so therefore will update to the latest 3.x version, in
this case 3.3.4-r9 because even though that in the testing branch,
you've just enabled it by adding it in your package.keywords file.

Although I don't know why portage doesn't also want to install the 4.1.1
version of qt if they are slotted...

Shawn
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Re: [gentoo-user] Re: QT 4

[Dmitry S. Makovey]

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On Thursday 16 March 2006 15:03, James wrote:
> Dmitry S. Makovey <dmitry <at> athabascau.ca> writes:
> > since packages you use (I assume KDE etc.) are not using qt4
> > (i.e. require specifically qt3 branch) portage doesn't find any
> > reasons to bump version of qt. AFAIR Qt is a slotted package and
> > you can safely go ahead and do
> > emerge =x11-libs/qt-4.1.1
> > but you packages wouldn't use it.
>
> Ok this kinda makes sense. But what exactly is a 'slotted package',
> how do I determine when a packages is slotted, and where do I read
> more about 'slotted'? I see this term used ofen, but, really have
> no clue exactly what slotted means or if it has various meanings
> based on the context of it's (verbiage) usage.

in /usr/portage/x11-libs/qt/qt-4.1.1.ebuild check the line SLOT="4" 
and compare it to /usr/portage/x11-libs/qt/qt-3.3.5.ebuild:
SLOT="3"

which indicates that those installed in different slots (in basic 
terms - those could be installed side by side without affecting 
existing applications unless they explicitly dependant on specific Qt 
version).

there are quite a few "slotted" packages in portage so you might bump 
into this every now and then (KDE is slotted AFAIR).

-- 
Dmitry Makovey
Web Systems Administrator
Athabasca University
(780) 675-6245

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Re: [gentoo-user] Re: QT 4

[Bo Andresen]

On Thursday 16 March 2006 23:43, Shawn Haggett wrote:
> Although I don't know why portage doesn't also want to install the 4.1.1
> version of qt if they are slotted...

That's because qt is neither in the world file or a depency of any package 
which is in the world file. It wants to upgrade to newest qt-3* because that 
is a depency of one or more packages in the world file.

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Re: [gentoo-user] Re: QT 4

[Holly Bostick]

Dmitry S. Makovey schreef:

> there are quite a few "slotted" packages in portage so you might bump
>  into this every now and then (KDE is slotted AFAIR).
Even easier-- so are kernel sources. Install a new one, and it's always
going to be [ NS ], not [ U ] .

Looking at how kernel sources are handled on the system seems to me to
be the easiest entry point to understanding SLOTs.

Holly
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Re: [gentoo-user] Re: QT 4

[Bo Andresen]

On Thursday 16 March 2006 23:03, James wrote:
> Dmitry S. Makovey <dmitry <at> athabascau.ca> writes:
> > since packages you use (I assume KDE etc.) are not using qt4 (i.e.
> > require specifically qt3 branch) portage doesn't find any reasons to
> > bump version of qt. AFAIR Qt is a slotted package and you can safely
> > go ahead and do
> > emerge =x11-libs/qt-4.1.1
> > but you packages wouldn't use it.
>
> Ok this kinda makes sense. But what exactly is a 'slotted package',

Slotted means that several versions of a package can coexist at the same 
system. In the case of qt version 3 goes into /usr/qt/3 and version 4 goes 
into /usr/qt/4.

> how do I determine when a packages is slotted, and where do I read
> more about 'slotted'? 

Have a look at 'man emerge'
# emerge -vp qt

These are the packages that would be merged, in order:

Calculating dependencies... done!
[ebuild  NS   ] x11-libs/qt-4.1.1  USE="..." 27,110 kB
                ^^^
The 'S' means that it is slotted.

On Thursday 16 March 2006 20:11, James wrote:
> I really confused as this is not very clear what the hardmasked, testing
> and stable versions of QT........?
>
> I've been told that QT 4 is 'very young' which I interpret as unstable
> and buggy. How do I tell if qt-4.1.1 is hard masked or testing....
> as I've never seen this before.

I would recommend app-portage/eix as it gives a clear overview of the 
available versions of any package.

# eix -e qt
* x11-libs/qt
     Available versions:  3.3.4-r8 ~3.3.4-r9 [M]3.3.5 [M]3.3.5-r1 4.1.0-r1 
4.1.0-r2 4.1.1
     Installed:           3.3.4-r8
     Homepage:            http://www.trolltech.com/
     Description:         The Qt toolkit is a comprehensive C++ application 
development framework.

Versions that are prefixed by [M] are hard masked usually because they are 
broken. They should not be unmasked without knowing why they were originally 
masked. Versions prefixed by a ~ are masked by ~ARCH i.e. testing and can be 
used by adding them to package.keyword. eix respects package.* an hence 
4.1.0-r1 is shown as stable because of this:

# grep x11-libs/qt /etc/portage/package.keywords
=x11-libs/qt-4.1* ~x86

As you can see you can specify versions to unmask if you want a testing 
version of qt-4.1* but stable for any other version. This is explained in 
'man portage'.

To see why a package is hard masked you have to look in the package.mask 
files.

Packages are masked on several levels. Both general and profile specific. On 
my system I am using the default-linux/x86/2006.0 profile.

# ls -ld /etc/make.profile
lrwxrwxrwx  1 root root 48 Mar 10 02:02 /etc/make.profile 
-> ../usr/portage/profiles/default-linux/x86/2006.0

Therefore packages on my system might be masked in the following locations 
(note that not all of those files actually exist because no packages are hard 
masked on some of those levels. Still these are the locations where portage 
will look.):
/usr/portage/profiles/default-linux/x86/2006.0/package.mask
/usr/portage/profiles/default-linux/x86/package.mask
/usr/portage/profiles/default-linux/package.mask
/usr/portage/profiles/package.mask

And the reason why qt-3.3.5 is hard masked:
# grep -A 2 Qt /usr/portage/profiles/package.mask
# Qt-3.3.5 causes a lot of compilation failures.
# See bug #106402.
~x11-libs/qt-3.3.5

But qt-4 is not hard masked so it should be working or at least it won't break 
anything. ;)

HtH

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[gentoo-user] Re: QT 4

[James]

Bo Andresen <bo.andresen <at> gmail.com> writes:


> Slotted means that several versions of a package can coexist at the same 
> system. In the case of qt version 3 goes into /usr/qt/3 and version 4 goes 
> into /usr/qt/4.

> > how do I determine when a packages is slotted, and where do I read
> > more about 'slotted'? 
               ^^^
> The 'S' means that it is slotted.


OK, thanks everyone, these explainations and the man pages make more sense now.

thanks everyone!

James

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Re: [gentoo-user] QT 4

[Glenn Enright]

On Friday 17 March 2006 08:11, James wrote:
> Hello,
>
> Has anyone any experiences with developing software with QT4?
>
> checking whats available, with 'emerge -pv qt', I see:
> x11-libs/qt-3.3.4-r8
>
> Nothing else... If I add x11-libs/qt to the package.keywords
> file, I get
> x11-libs/qt-4.1.1

Just out of interest how far along is qt4? Last time I looked the next major 
release of kde *might* be using it, if it becomes stable in time. Is this 
still the case?

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Re: [gentoo-user] QT 4

[Uwe Thiem]

On 17 March 2006 05:16, Glenn Enright wrote:

> Just out of interest how far along is qt4? Last time I looked the next
> major release of kde *might* be using it, if it becomes stable in time. Is
> this still the case?

The current version is Qt-4.1.1 AFAIK and it's pretty stable.

KDE4 will be base on Qt4, no "if".

Uwe

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[gentoo-user] Re: QT 4

[James]

Uwe Thiem <uwix <at> iway.na> writes:


> > Just out of interest how far along is qt4? Last time I looked the next
> > major release of kde *might* be using it, if it becomes stable in time. Is
> > this still the case?

> The current version is Qt-4.1.1 AFAIK and it's pretty stable.

> KDE4 will be based on Qt4, no "if".

Hello Uwe,

So when will we see KDE-4?

A group is coallescing together to develop a SCADA package and associated
tools, much like National Instrument's Lookout, which is part of Labview. 
Would you be willing to provide some QT4 architectural issues advise, 
as we formalize a formal plan? Graphical creation of industrial devices,
such as valves, pumps, tanks, guages and many types of machines and instruments,
with  animation and inserts of actual equipment pictures, all in a SCADA
package is of keen interest to this development effort.

If any other Gentoo-users have a keen interest in remote controls and SCADA 
tools sililar to National Intruments Labview, drop me a line with a brief
message about your interests. SNMPv3 and many industrial protocols, such as 
modbusTCP will be supported.


James







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Re: [gentoo-user] Re: QT 4

[Uwe Thiem]

On 17 March 2006 18:48, James wrote:

> Hello Uwe,
>
> So when will we see KDE-4?

My personal opinion? At the earliest end of this year - but honestly, I doubt 
it. More probably, there will be a a "developer alpha" or some such by the 
end of 2006. One with a stabilised API but not necessarily feature complete 
or ready for production. KDE did the same thing with version 2 to give 
application developers a chance to port their apps to the new framework.

I expect KDE4 somewhen first half of 2007. That's personal opinion. There 
isn't any real roadmap yet.
 
>
> A group is coallescing together to develop a SCADA package and associated
> tools, much like National Instrument's Lookout, which is part of Labview.
> Would you be willing to provide some QT4 architectural issues advise,
> as we formalize a formal plan? 

IMO, Qt's help with their classes overview and their tutorials is first-class 
documentation. If you have specific questions we can take it from there. But 
I must admit I haven't done much with Qt4 personally yet.


> Graphical creation of industrial devices, 
> such as valves, pumps, tanks, guages and many types of machines and
> instruments, with  animation and inserts of actual equipment pictures, all
> in a SCADA package is of keen interest to this development effort.
>
> If any other Gentoo-users have a keen interest in remote controls and SCADA
> tools sililar to National Intruments Labview, drop me a line with a brief
> message about your interests. SNMPv3 and many industrial protocols, such as
> modbusTCP will be supported.

Sounds interesting.

Uwe

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