Safe to install QT5 and QT6 concurrently? [SOLVED] YES

[geo_c]

I'll post here since I'm running KLV-airedale and KLV-spectr playing around with portable versions of Double Commander

My installs are running QT5 and I haven't installed QT6, and it seems that portable DoubleCommander doesn't find libraries it needs.

Is it safe to install QT6 along side QT5?

A quick web search didn't give me a clear answer.

[Clarity]

I am not a user of Double Commander, so I admit stupidity in its requirements. BUT,, I offer this as I know you have used these.

Boot either of your KDE ISOs, install Double Commander, does it work? If so, this offers some insight. If you boot their ISO files, the time to do it and test is less that 2-3 minutes, max.

This may not be helpful, yet would be insightful as future KLs may all advance to QT6 as well as GTK4 only for apps that the distros provide.

[geo_c]

Boot either of your KDE ISOs, install Double Commander, does it work? If so, this offers some insight. If you boot their ISO files, the time to do it and test is less that 2-3 minutes, max.

This may not be helpful, yet would be insightful as future KLs may all advance to QT6 as well as GTK4 only for apps that the distros provide.

Well you're right KLV-KDE-Plasma-CE-1 runs DoubleCommander-qt6 just fine:

And I forgot how nice this KLV-Plasma is, I erased it from bare metal because I needed drive space, but I booted a USB install for this test. It's very nice! BUT, I still don't like running as normal user, I'm a spoiled run-as-root puppy brat unfortunately.

And as you can see from the screenshot, I fired up Double Commander portable from Xfe-su, which I launch as root user from a desktop file.

[geo_c]

Everything I'm reading, which are mostly forum posts discussing software compatibility and backward compatibility between Qt5 and Qt6 seems to me to be indicating that both of them don't exactly coexist in the same environment.

It looks to me like upgrading to Qt6 means you're running Qt6.

But I'm not finding specific references to back up what it appears to be from these posts, just statements on other topics which suggest it's one or the other Qt environments on a given system.

@Clarity do you have an ideas about it?

I guess to test, I'll just backup my upper_changes, try installing QT6 from the Void repos and see what happens.

note: it's not that I need QT6 to run Double Commander, as Double Commander GTK runs fine in all systems, I'm just curious now about the ins and outs of QT upgrades.

[Clarity]

...@Clarity do you have an ideas about it? ...

No, I dont. I do understand your question on co-existence.

I am NO USE as I have done little in programming in Linux in my lifetime. The 2 primary manners of putting multi-choice window screens on a desktop are both GTK and QT6 in linux. QT6 has a reputation for being the most robust in features, as I understand it. Last year I took a look and had an app that I was considering creating and the students told me that QT was a much-much better suite for the app I was considering due to its ability to do things within the app window that GTK could not do. It has a design abilty where I would not need to go-out of the window and back-in multiple that GTK would require. There preliminary showed me that, helpfully as the QT version accomplished everything, including status results, all within the same window.

GTK works well with scripts while QT6 is ground in programming language.

That's all I know. I do recognize my knowledge is Probably Inaccurate, though.

Nice to see you proven the Double Commander abilty in KDE that @Sofiya has provided this forum.

P.S. I attended a seminar few years back on QT6. Seem to remember their insistence that apps were backward compatible,; unlike GTK apps. IFF true, there may be "no harm" in upgrading a system to the latest QT...now at version 6.

[dimkr]

Applications that use Qt5 need to be ported to Qt6 before they can use Qt6. While it should be a relatively easy process, it's work that needs to be done: you can't just rebuild a Qt5 application against Qt6 and expect things to work, and can't swap Qt5 with Qt6 and expect already built applications to work.

This incompatibility is the reason why Qt5 and Qt6 are co-installable: they use different library names so you can install and use applications that use Qt5 alongside applications that use Qt6. If you install Qt6, it won't magically make all applications that use Qt5 suddenly use Qt6. There's no point in talking about the benefits of Qt6 over Qt5, because it's not a drop-in replacement, and you'll be able to reap these benefits only in applications built against Qt6.

(Same story as with GTK 2, 3 and 4, and the Qt 4 to Qt5 migration - the incompatible major versions are co-installable, and applications need to be ported.)

That's all I know. I do recognize my knowledge is Probably Inaccurate, though.

It's wrong, not just "inaccurate".

There's so much misinformation in this forum!

P.S. I attended a seminar few years back on QT6. Seem to remember their insistence that apps were backward compatible

Porting guides like https://doc.qt.io/qt-6/portingguide.html exist because Qt is not backward compatible and applications need to be ported to use a newer version.

[Clarity]

...

That's all I know. I do recognize my knowledge is Probably Inaccurate, though.

It's wrong, not just "inaccurate".
...

You DO offer great and useful information as the developer you are!

But you continue to be a "piece of work" in your behavior and constant position to show your percieived SUPERIORITY to the rest of us with your off-handed comments.

I made the statements I did, acknowledging my lack of knowledge.

At this point of witnessing your activity over the past, one would have assumed you would have beome more enlightened. But that part of your development may never occur.

Continue on @dimkr as you do ... Oh SUPREME ONE!

[dimkr]

I made the statements I did, acknowledging my lack of knowledge.

OP had a simple question which has a simple answer.

If you don't know the answer, I don't understand why you're trying to answer it based on false or unrelated information. Suggesting that Qt5 and Qt6 are compatible (which is 100% wrong) while mentioning some seminar you attended (suggesting that you have confidence in your answer) can waste people's time if they remove Qt5, install Qt6 and wonder why their applications don't start anymore.

Silence is golden.

[geo_c]

I made the statements I did, acknowledging my lack of knowledge.

OP had a simple question which has a simple answer.

If you don't know the answer, I don't understand why you're trying to answer it based on false or unrelated information. Suggesting that Qt5 and Qt6 are compatible (which is 100% wrong) while mentioning some seminar you attended (suggesting that you have confidence in your answer) can waste people's time if they remove Qt5, install Qt6 and wonder why their applications don't start anymore.

Silence is golden.

To be fair, I did ask @Clarity point blank if he had any ideas, since he was active on the topic already. I appreciate you both.

And the answer is a simple yes, QT is like GTK in that you can have multiple versions installed for compatibilty with various applications.