Linux.... mmmm...

GrumpyDave

So I want to put qt 5.14 or later on my ubuntu 20 box because it is a requirement for savvyxcan that I want. The issue is that ubuntu provide an install for an older version.
Fine I says to myself I will go through the pain in the bottom that is getting an account and all the rest of it for the qt website, and here I am.
I find myself at https://my.qt.io/ which nicely has a link to download... fair enough, nice to see that so I follow it.
It contains some info and finally I find a link to download a qt online installer.
I download it, it comes down as a most odd filename indeed include single quotes and a (1) even though it is the only version on my machine and without any executable flag. Now having adjusted the filename to something sensible and chmoded to add executable I can run it. But after an endless wait it turns round and errors claiming it cant start ..."This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem." Please, I am NOT trying or even wanting to be a QT guru, ALL I want - and it should be TRIVIAL is to use an application that has been developed with it. The build of that application fails claiming error: ‘textActivated’ is not a member of ‘QComboBox’ which I take to be an indication of a breaking change to an API introduced at some undocumented random version so I merely tried to add a more up to date one than the default Ubuntu installation.

Really, should any of it be this damned difficult? How long has QT existed - isnt it decades?

SGaist

Hi and welcome to devnet,

You are likely missing one of Qt's dependencies.

Start the installer from the command line with the QT_DEBUG_PLUGINS environment variable set to 1. It should give you the reason why the plugin could not be loaded.

Paul Colby

Hi @GrumpyDave,

I can understand your frustration (and appropriate username ;) but this is not Qt's fault. The root issue you're up against, is that you're using a very old (albeit LTS) Ubuntu release that only provides an equally very old version of Qt, and you're trying to use a an application that was not written to support such an old Qt version.

ALL I want - and it should be TRIVIAL is to use an application that has been developed with it.

While you could go through the effort of downloading a more modern Qt, and building SavvyCAN yourself (something that it not recommended for the inexperienced), why not use SavvyCAN's AppImage instead? It already includes all of the necessary Qt libraries within it (or at least it should).

You can get the latest AppImage from their release page here: https://github.com/collin80/SavvyCAN/releases

Just download the *.AppImage file (eg SavvyCAN-da5e502-x86_64.AppImage), chmod u+x the file, and run it. I don't have any Ubuntu 20 machines around to test, but it works on all the Ubuntu's I do have handy.

I download it, it comes down as a most odd filename indeed include single quotes and a (1) even though it is the only version on my machine

That is very odd, and not something I've ever seen from official Qt sites. I just did a quick check for fun, and wasn't an issue for me. Honestly, I'd be a bit concerned about your machine being compromised, or at least having a buggy browser plugin or something if it was me. Just for curiosity, do you happen to have the original download link? (You should be able to see it in your browser's download history)

and without any executable flag.

That's a browser security restriction. Browser's will never let a downloaded file have the execute permission already set (on any OS that has such permission bits).

Good luck.

Cheers.