[blfs-dev] lxqt - final comments

Fernando de Oliveira famobr at yahoo.com.br
Fri Aug 14 07:18:07 PDT 2015

Em 13-08-2015 16:41, Ken Moffat escreveu:

Thank you very much for testing it.

Do the reboot and shutdown buttons work now?

In what follows, I will write what I understand (or don't understand) is
needed to modify in the book. Please, reply with comments, or just yes,
if I understood correctly.

> I said I would make some more comments on lxqt, but that got
> sidelined by the stylesheets and firefox.  Some of the things I
> flagged up (particularly, the library directory where not mentioned
> in the book) were bogus.  The book instructions are ok.

I will try to understand the "library directory" issue and try to solve it.

> But finally, here are my remaining comments -
> 1. I built it in /usr - works for me.
> This was with qt5 in /opt : for lxqt, I cannot see any pressing reason
> to build lxqt in /opt.  So, I used $LXQT_PREFIX in my scripts.
> My personal view is that Qt also belongs in /usr - in my normal
> desktop builds I only put two things into /opt : llvm (to ensure it
> will not be used by accident - I have to add it to $PATH when I want
> to use it), and texlive.

For me, it was a question of convenience: had to add a more or less
"large" number of packages, without knowing what would work or not. Easy
to remove afterwards (and I did remove and reinstall several times).

I wouldn't mind if you modify the instructions to add$LXQT_PREFIX and
optionally install either in /usr or /opt. Actually, I would appreciate
that modification. Don't know if we have time to do it before freeze.

> 2. kf5 dependencies
> On the face of it, only the two named packages (kwindowsystem,
> kguiaddons) are needed, plus the matching extra-cmake-modules.  I
> dropped these into /usr rather than having kf5 in my PATH during
> this build.  I would hate people to get the mistaken impression
> that all of kf5 is needed here.

I think you are suggesting that where the two referred packages are
mentioned, I add a warning that only those are needed.

> 3. lxqt-common and another windowmanager -
> Note that icewm is NOT a valid replacement (you get icewm without
> any of the lxqt additions).  Fluxbox does work, although in this
> context (with lxqt-config) openbox is better.  The windowmanager
> you are using needs to be in both /etc/xdg/lxqt/windowmanagers.conf
> and there the Name is actually the _command_, e.g.
> fluxbox/Name=startfluxbox
> and then you can change the windowmanager= line in
> /etc/xdg/lxqt/session.conf.

OK. I need to add those comments, first generally, and then, with your

> 4. lxqt-runner : does this do anything, or show up in a menu ?
> I had assumed it would let me type in the name of the program I
> wanted to run, but could not find any way to do that.

OK. Need to add a paragraph about this: At-F2 opens at the center top a
small window where the program name can be typed. It is always running:

$ pgrep -l runn
4958 lxqt-runner

> 5. For juffed, at first this did not appear on menus, so I could
> only try to start it from a term.  But that gave me:
> juffed: error while loading shared libraries: libqt5scintilla2.so.12:
> cannot open shared object file: No such file or directory
> In this case, QScintilla is in /opt/qt5/lib - running ldconfig
> fixed the problem : I am ambivalent about whether the QScintilla or
> the juffed install is the right place to do that, but I guess that
> doing it in QScintilla is probably better.

Right. It doesn't hurt including it for both packages. Usually, never
have this kind of problem, because all my scripts run ldconfig even if
there is no library installed. This (bad?) habit started years ago, when
I was learning to CMMI.

> I'll try not to mention my experiences with juffed too much (I hated
> it), but when I was running it from a term (looking at a bash
> script) it segfaults when closed - if run from a menu you will not
> notice that.

LOL. Not surprised that you disliked. I am using it for most things. But
vim's syntax highlight, for my experience, is unbeatable.

> ken at ac4tv ~ $juffed
> libpng warning: iCCP: known incorrect sRGB profile
> libpng warning: iCCP: known incorrect sRGB profile
> iconTheme "oxygen"
> "[03:08:54]" "--- Plugin 'Autosave' is disabled in Settings."
> "[03:08:54]" "--- Plugin 'Color Picker' is disabled in Settings."
> "[03:08:54]" "+++ Plugin 'Documents List' was loaded successfully."
> "[03:08:54]" "+++ Plugin 'Favorites' was loaded successfully."
> QObject::connect: No such signal FindWorker::terminated()
> "[03:08:54]" "+++ Plugin 'Find In Files' was loaded successfully."
> "[03:08:54]" "+++ Plugin 'File manager' was loaded successfully."
> "[03:08:54]" "+++ Plugin 'Keybindings' was loaded successfully."
> "[03:08:54]" "+++ Plugin 'Sort Document' was loaded successfully."
> "[03:08:54]" "+++ Plugin 'Symbol_browser' was loaded successfully."
> default KB_LAYOUT_DIR:  "/usr/share/qtermwidget5/kb-layouts/"
> Session::run() - program: "/bin/bash"
> Session::run() - arguments: ("")
> started!
> loadAllColorSchemes

> Using an unsupported variable-width font in the terminal.  This may produce display errors.
> Using an unsupported variable-width font in the terminal.  This may produce display errors.

Those two lines don't appear for me.

> default KB_LAYOUT_DIR:  "/usr/share/qtermwidget5/kb-layouts/"
> "[03:08:54]" "+++ Plugin 'Terminal' was loaded successfully."
> "[03:08:54]" "+++ Plugin 'XML Formatter' was loaded successfully."

> "[03:08:54]" "Session '/home/ken/.config/juff/sessions/_empty_session_' opened successfully"
> "[03:08:54]" "Session '/home/ken/.config/juff/sessions/_empty_session_' was parsed successfully"

Here, I have:

"[08:04:34]" "Session '/home/fernando/.config/juff/sessions/blfs' opened
"[08:04:34]" "Session '/home/fernando/.config/juff/sessions/blfs' was
parsed successfully"

> Using an unsupported variable-width font in the terminal.  This may produce display errors.

Above line doesn't appear for me.

I have, not Ken:

QFileInfo::absolutePath: Constructed with empty filename

> "[03:10:09]" "  Entering tabRemoved (TabWidget.cpp:113)"
> "[03:10:09]" "    Entering onTabRemoved (DocViewer.cpp:434)"
> "[03:10:09]" "    Leaving  onTabRemoved (DocViewer.cpp)"
> "[03:10:09]" "  Leaving  tabRemoved (TabWidget.cpp)"

Above, Ken, not Fernando.

> QProcess: Destroyed while process ("/bin/bash") is still running.
> Segmentation fault

Thanks for that!!!

(BTW, minutes before starting to reply, FF crashed, after one day
without problem. I'm looking forward to start creating the tickets,
hoping that FF-40.0.2 fixes that.)

Spent the day up to now investigating that. I'm almost sure that the
problem is with qtermwidget.

This was suggested by gdb, running a -DCMAKE_BUILD_TYPE=Debug DESTDIR
install, instead of Release:

QProcess: Destroyed while process ("/bin/bash") is still running.
[New Thread 0x7fffdb44d700 (LWP 20210)]

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff5d6a06a in QObject::removeEventFilter(QObject*) ()
   from /opt/qt5/lib/libQt5Core.so.5

Back Trace:
(gdb) bt
#0  0x00007ffff5d6a06a in QObject::removeEventFilter(QObject*) ()
   from /opt/qt5/lib/libQt5Core.so.5
#1  0x00007fffda1c6766 in Konsole::TerminalDisplay::~TerminalDisplay() ()
   from /usr/lib/libqtermwidget5.so.0
#2  0x00007fffda1c6989 in Konsole::TerminalDisplay::~TerminalDisplay() ()
   from /usr/lib/libqtermwidget5.so.0
#3  0x00007ffff5d6177b in QObjectPrivate::deleteChildren() ()
   from /opt/qt5/lib/libQt5Core.so.5
#4  0x00007ffff6a3e0ff in QWidget::~QWidget() ()
   from /opt/qt5/lib/libQt5Widgets.so.5
#5  0x00007fffda1b0a99 in QTermWidget::~QTermWidget() ()
   from /usr/lib/libqtermwidget5.so.0
#6  0x00007fffda3fc830 in TerminalPlugin::~TerminalPlugin() ()
   from /usr/lib/juffed/plugins/libterminal.so
#7  0x00007fffda3fc909 in TerminalPlugin::~TerminalPlugin() ()
   from /usr/lib/juffed/plugins/libterminal.so
#8  0x00007ffff5d2b0f5 in ?? () from /opt/qt5/lib/libQt5Core.so.5
#9  0x00007ffff5d2c4ab in ?? () from /opt/qt5/lib/libQt5Core.so.5
#10 0x00007ffff499812f in __cxa_finalize () from /lib/libc.so.6
#11 0x00007ffff5b3ee43 in ?? () from /opt/qt5/lib/libQt5Core.so.5
#12 0x00007fffffffdb10 in ?? ()
#13 0x00007ffff7dea727 in _dl_fini () from /lib64/ld-linux-x86-64.so.2
Backtrace stopped: frame did not save the PC

After some searches, found many references for '"qtermwidget"
segmentation fault' and a patch (for reasons that I can't remember any
more I assumed was for that problem):


Reinstalled qtermwidget and juffed, but still got the segfault.

Reinstalled juffed with -DBUILD_TERMINAL=OFF, and the segfault is gone.

Thinking of warning about that. Have used the terminal and it works, but
never use it. Or do you think that it would be better a recommendation
against it?

> 6. qupzilla : I question the point of the sed for the menu - I did
> not do this, and in both plasma and lxqt (with fluxbox) it appears
> alongside the other browsers.

OK. I did have a problem, but cannot reproduce any longer. Will remove it.

> 7. The apps except lximage-qt are all in /usr - that reinforces my
> feeling that it should probably all be in /usr.

OK. Wrote about that above.

> ĸen

Ken, thank you very much, again!

Will do the modifications in my next commit.

Starting the day, now.


More information about the blfs-dev mailing list