This worries me about our current GTK2 standard

[cdbc]

Hi Curt
Yes, I too think it's your *buntu, that's too old, or at least Qt5.
In that case you have to patch the API, so that it doesn't expect those symbols, with a bit of careful fiddling, that's absolutely doable 
Look at my example zip, it has some of them, as far as I can see, then it's just a matter of doing the rest in the same style... Remember to back up the files you touch beforehand!!!
...And ofc. you'll need writing rights in /usr/lib/lazarus/lcl/interfaces/qt5/*
Albeit - temporarily 
Just take it easy, it's not that hard...
I ran Qt5 for a couple of years this way, 'cause our fearless leader in PCLinuxOS is a wee bit conservative -- It has to work! -- so I had an older Qt5 on my machines.
Regards Benny

[Curt Carpenter]

Used synaptic package manager to install llibqt5pas-dev on my Ubuntu24 64bit system this morning -- and changing an application from gtk2 to QT5 widget set worked seamlessly.   

So it seems my problem is between Ubuntu18 and the current version of libqt5pas-dev.  One more reason I really need to migrate permanently to the 64bit box I guess.

Thanks again for everyone's help. 
 

[PeterBB]

But how long will it take for major dists like Debian/Ubuntu/Fedore/Suse/etc.. to begin thinking about retiring GTK2?

For Debian, its ongoing;
https://lists.debian.org/debian-gtk-gnome/2025/11/msg00014.html

"I think we should send a debian-devel email in December announcing
our goal for the final stage of the gtk2 removal."



Regards,
Peter

[dbannon]

Yes, I reckon it was two years ago I had a msg from debian reporting a bug against my app. It was not a fatal one but a bug never the less. So I moved over to Qt5 there and then for Debian. But I still make a gtk2 package available from github for people who want it.
Davo

[Thaddy]

Not enough people are acutely aware that gtk2 will disappear from most serious distro's or have already disappeared.
The fact that in ubuntu 24 you can still do this:

Code: Bash  [Select][+][-]

1. sudo nano /etc/gdm3/custom.conf
2. #uncomment #WaylandEnable=false
3. WaylandEnable=false

save and reboot. Will certainly disappear.

The above gives you full X, not xwayland. Expects Gnome.

[dbannon]

Not enough people are acutely aware that gtk2 will disappear from most serious distro's or have already disappeared.

That is definitely true. But the necessary libraries will remain in repos for some time. So, they can be installed, but over time, will probably become unreliable because no one is bothering to test. Try running a gtk(1) app if you can find one.

And, because of the mad race to get rid of gtk2, its a bad look to have your flagship product shipped with gtk2. Lazarus, for example. But if the Lazarus Devs change the downloadable binary to, say, Qt5, all those "long term" distros won't have a suitable libqt5pas in their repo. Oh !

WaylandEnable=false

I am not sure what that means. Its still available in U2410 but as far as I can see does nothing. gtk2 apps seem to run in that mode exactly the same as they do otherwise. Same bugs in poweroff for example. On my working laptop, running Mate (and therefore lightdm) there is no option to disable (or, of course, enable) Wayland.

gtk2 is on its way out. Wayland is on its way in. Both events are inevitable but generally unrelated IMHO ??

Davo

[Thaddy]

Well,partly agree, but choose Qt6 and don't be surprised if GTK2 is NOT in future distro's because it is unmaintained. That is my worry.

[zeljko]

Used synaptic package manager to install llibqt5pas-dev on my Ubuntu24 64bit system this morning -- and changing an application from gtk2 to QT5 widget set worked seamlessly.   

So it seems my problem is between Ubuntu18 and the current version of libqt5pas-dev.  One more reason I really need to migrate permanently to the 64bit box I guess.

Thanks again for everyone's help.

If you cannot find adequate libqt5pas for your ubuntu 18, you can use qt4 (qt widgetset) which should work oob with older distros. Qt ws is still maintained by me in lazarus.

[Curt Carpenter]

Thanks -- I will check that out.  I've started to seriously transfer my projects to the 64bit system now, so it may be a while before I try it.