Arch Linux

scot

Member

Registered: 2017-04-22

Posts: 36

Is it a bug: Qt app dumps core when DISPLAY is not set correcly

I was trying to configure the built-in webcam on my  Dell XPS Inspiron 7577 which is now running an up-to-date Arch Linux installation. I have the following interaction:

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[root@scott-dell7577 ~]# qv4l2
qt.qpa.xcb: could not connect to display
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, xcb.

Aborted (core dumped)
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It took me a few moments to understand that the problem was, uh, that qt.qpa.xcb could not connect to the the display .
The reason being, of course, that I was not running X as root, but as my regular user.
I am writing here to ask about the last line: "Aborted (core dumped)".  I ask: is it considered "correct behavior" and not a bug EVER to abort and dump core?
Is the right thing to do just to not be so stupid and run the program as "me", and otherwise to shut up? Or
is the right thing to do to report that qt.qpa.plugin has a bug and dumps core when it cannot connect to the display? Or
is the bug with the qv4L2 application and not with qt at all?

I realize that there are more important problems in the universe, but I'd like to start my new life journey with archlinux by doing the "right thing."

Thanks for the advice

scott

Last edited by scot (2020-03-30 01:00:19)

Trilby

Inspector Parrot

Registered: 2011-11-29

Posts: 30,530

Website

Re: Is it a bug: Qt app dumps core when DISPLAY is not set correcly

I ask: is it considered "correct behavior" and not a bug EVER to abort and dump core?
Is the right thing to do just to not be so stupid and run the program as "me", and otherwise to shut up?

A bit of both.  It is an upstream issue that should be reported, the program should error out more gracefully than that.  But why are you trying to run that as root?

Most importantly, though, please edit your post to select a title that actually represents your problem.

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"UNIX is simple and coherent" - Dennis Ritchie; "GNU's Not Unix" - Richard Stallman