I've recently installed Ubuntu 22.04 LTS on my development laptop. Previously I was running 18.04 so this is my first experience of Wayland. I did a clean installation on a new disc. I had relatively few problems reinstalling gitkraken and cloning the repository of my source code from github but when I came to install the Qt libraries this is where my problems started. The on-line installer from the Qt website simply wouldn't run. It just exited silently. I eventually found an old version of the on-line installer executable in a backup of my downloads folder from Ubuntu 18.04 and was able to use this to download and install the same version of the Qt libraries that I was using previously (5.15.0). This is also the same version that I use on my other development machine which runs Windows 10. Keeping the two in step is useful and upgrading too many things at the same time seemed like asking for trouble. I installed the latest versions of Qt Creator (7.0.1) and g++ (11.2.0).
I was then able to build my application and, after a brief search of stack overflow I added "-platform wayland" to the command line arguments setting in Qt Creator but the application crashed almost immediately on start-up with the error "The Wayland connection experienced a fatal error: Protocol error".
Several things made me think this might be a bug in the Qt libraries rather than my application (none of them definitive!):
At the point of application exit, apart from main() there is none of my application code in the call-stack (see below)
My application has been stable for a long time and has survived several operating system, compiler and Qt version changes across two OS families
The fact that the latest Qt on-line installer (itself almost certainly a Qt application) wouldn't run
I downloaded Qt 5.15.12 (the latest Qt 5 version available) and rebuilt my application against that but the result was the same.
The next step is obviously to strip my application right down to something minimal that still shows the problem but before I do I was wondering whether this is something other people have come across when migrating a Qt5 application to Wayland and whether I need to take the bigger step of upgrading to Qt6? The Qt Wiki describes Qt 5.11 as being "stable" with Wayland.
The call stack at the time of the error looks like this:
qt_message_fatal
QMessageLogger::fatal
QtWaylandClient::QWaylandDisplay::checkError
QtWaylandClient::QWaylandDisplay::flushRequests
doActive
QMetaObject::activate
QSocketNotifier::activated
QSocketNotifier::event
QApplicationPrivate::notify_helper
QApplication::notify
QCoreApplication::notifyInternal2
QCoreApplication::sendEvent
socketNotifierSourceDispatch
g_main_context_dispatch
??
g_main_context_iteration
QEventDispatcherGlib::processEvents
QEventLoop::exec
QCoreApplication::exec
main
Many thanks.
It's something to do with QDialog::setMaximumSize. The call to setMaximumSize itself does not crash but if I remove all calls to it the application works fine. Some controls do subjectively seem bigger on Wayland so I wonder if Qt 5 on Wayland crashes if the size of the QDialog contents exceeds the maximum size specified. This certainly doesn't cause a crash in Qt 5 on Windows and didn't in Qt 5 on Ubuntu prior to the switch to Wayland. I think this is a Qt bug but of course it may well be fixed in a later version of Qt and there's an easy enough work-around now I know the cause.
I was using setMaximumSize to allow the dialog to expand dynamically as widgets were added but to prevent the user from making the window any bigger than it needed to be. layout()->setSizeConstraint(QLayout::SetFixedSize); achieves the same thing.
Related
Here’s what happens
I open the installer, choose the packages I want(I choose to install some 1.7 GB of components), everything goes well.
But then when I click on the Install button, and Qt installer crashes! And by crashes I mean it crashes, Windows DOES NOT tell me it is not responding. The window just gets invisible from the taskbar.
There also is no possibility that it is installing in the background, as I waited for approx. 5 mins, and when I checked in the folder where I was going to install it, I didn’t find a SINGLE component installed!
How to solve that?
I asked some questions earlier because a person needs more information. It also depends on what compiler you have. There are many many known issues with Qt 6.x.
The default kit doesn't work with MSVC2019
https://forum.qt.io/topic/120357/wrong-kit-for-qt-6-0-0-msvc2019-64bit/5
Qt 6.0 has install issues with GLib 6
https://youtu.be/IZy6FMQlaNg
There also appears to be significant problems with OpenGL.
https://github.com/opencv/opencv/issues/20499
People seem to still be able to get off-line installers, and, as this French typing person found out, you have to be careful because it appears there are some 32-bit Windows kits.
https://forum.qt.io/topic/123027/installation-qt6-on-windows/7
If you try running them on a 64-bit Windows 10, they crash.
If this doesn't answer your question, you need to supply
Which Windows Version
32 or 64-bit
off-line or on-line installer?
I'm trying to set up the environment on the new machine for our application written on Qt15.2 with GCC compiler version 10.2, and because it is a windows application, I get the qt and gcc from the MSYS2.
The compiling process is going well, but when I'm trying to launch the application, it crashes with the message: "the program has unexpectedly finished. the process was ended forcefully"
The same I obtained if trying to compile a blank qml app with a single ApplicationWindow in it.
I will be very grateful for your help.
The solution was found - I used "dependencies" (https://github.com/lucasg/Dependencies) to find out, which .dll libraries are missing. The problem was in some Windows libraries because it was a fresh system downloaded from Microsoft site without any updating made yet and seems to be very old. I had updated the system and everything is working fine now.
In a nutshell, the question is: I just finished my first application using Qt Creator on a computer running under Linux Ubuntu, now how do I make this available for everyone. Now follows the more detailed version ;)
I must apologize for asking this, I am aware that this question has probably been asked many times and that there is official documentation that I can read. I am just completely new to programming and I am very confused by everything I've read so far. If you are kind enough to help, please assume I know absolutely nothing :)
Here we go: I've just finished designing my first application (a scientific program) with Qt creator on my laptop which runs under Linux Ubuntu. It works fine and I'm very proud of it ;)
Here's what my project consists of: 40 header files, 42 source files, 1 pro file, 1 qrc file, 1 html file and 7 png files. In the code, I use #include for a bunch of fairly standard Qt classes (QWidget, QTextBrowser and so forth, maybe like 40 of those).
Now I'd like to make it available to other people. For Linux and Mac users, I've figured a way to do that: I can compress the folder containing my project, tell them to install Qt on their computer, then download and extract the files on their hard disk, open a terminal in the folder and run
qmake myProject.pro
qmake
make
That seems to work fine (by the way, does it matter that this is not precisely what Qt creator does? The qmake step there is qmake-qt4 myProject.pro -r -spec linux-g++ and the make step is make -w). Now, I assume there is a solution where I don't ask them to download and install something like 200Mo of Qt material. As for Microsoft Windows users, I don't have a clue.
I would be very grateful if you could explain to me in a very concrete way what I need to do. Needless to say, I'll go for the best and easiest solution, I don't need to understand everything about deployment. Many thanks in advance!
Edit: In case that's useful : I've been using Qt Creator 2.5.0 based on Qt 4.8.1 (64 bit), I'm working on a laptop with Ubuntu 12.04 64bits
For Linux and Mac users, I would compile the software for them in 32 and 64bit formats - no-one likes compiling unknown software from source. Obviously keep the source code option for those on more unusual architectures/OSs (and provide a shell script for them that mimics the commands Qt Creator calls!). As Qt runtimes are available from package managers on just about every distro (and come pre-installed on most anyway, KDE requires them for example), by not asking them to compile from source your users will have a much smaller download (if any) and won't require them to download software from a website potentially unknown to them. Of course the best way would be to try to get your software added as a package into the major distros' repositories, but that may take some time to organise.
Compile your software for Windows users for both 32 and 64bit formats. It's generally frowned upon to ask users to download runtime libraries they potentially don't know, and put them into their system32 folder... So most applications bundle all the libraries they need with their application. Qt-based applications are no different, and so put the runtimes into the folder where the executable is. Also it is much more professional to create a proper installer, there are a few free installer applications for Windows, a web search will give you the most popular (I think I saw a thread on SO about it as well).
As you can see the platforms aren't too dissimilar, the main point I would make is: Do not force people to compile from source! The vast majority of people on Earth do not even know what compiling is, so provide for the major arrchitectures/OSs yourself.
The C++ program I am writing under Linux (OpenSuse) had a bug in it where it consumed all available RAM including page memory. This affected badly the system and all programs it was running. More importantly eclipse (amongst other programs) was unable to close properly and I eventually had to power off the machine.
After powering the machine back up again and restarting eclipse all seemed well except when compiling under eclipse it now compiles both the debug and release versions whenever I press Control-B, my usual short cut.
So the question is how do I recover from this situation whereby I had a debug and release version of the program and Control-B would compile either the debug or release version but not both. I see this as an inconvenience but as the program gets larger the compile times are getting longer (twice as long as necessary) and I can only drink so much tea whilst I wait.
To answer my own question.
The Control-B short cut does a 'Build All' and so the answer is 'As Designed'.
But this begs two other questions.
Firstly I am sure that previously the Control-B short cut only compiled the Debug version. So I have no idea how I got eclipse to do that. That was something I did a long time ago.
Secondly how do I get just a Debug or a Release build but not both. I cannot discover an option for this. On my setup the 'Build Project' option still invokes both Debug and Release builds.
I've been coding with Python and C++ and now need to work on building a gui for data visualization purposes. I work on Mac Snow Leopard (intel), python 3.1 using gcc 4.2.1 (from Xcode 3.1)
I wanted to first install Qt and then PyQt. And my goals are to be able to:
- quickly prototype GUI and the accompanied logic that drives the GUI using PyQt and python
- if I decided I need the speed, or if it's fairly easy to translate my GUI into C++ using the Qt tools, I have the options to translate my app into C++
- Be able to deploy my application onto Windows (both the python and c++ version of my app)
Give the goals above, what are the correct steps I should take and what issues i should be aware of when setting up Qt and PyQt. Which other deployment tools do I need?
From my readings so far, here's what I have:
download the Qt source for mac and configure it with
-platform macx-g++42 -arch x86_64 -no-framework
(i've read somewhere that
building as framework causes some
trouble in deployment and/or
debugging, can't find the article
anymore)
download latest SIP source and build
download latest PyQt and build from source (any special options I should pay attention to?)
For deployment, I've read that I would need to use py2exe/cx_freeze for windows, p2app for mac:
http://arstechnica.com/open-source/guides/2009/03/how-to-deploying-pyqt-applications-on-windows-and-mac-os-x.ars
but seems like what the article describe is deploying an app you build on windows on the windows platform and vice versa. How do you deploy to windows (is it even possible?) if you are writing your Qt app on a mac ?
Really appreciate the help
I'm guessing by deploying, you mean a compiled version to users that have no Python or Qt or anything.
I'm been trying py2app for a while now and never really worked out for me. You can try PyInstaller. It worked out pretty well for me since it's made to work with plugins like PyQt and PIL etc. I put up some instructions here
http://tech.xster.net/tips/deploy-pyqt-applications-on-mac-os-x-with-pyinstaller/
They don't really support cross-compilation though. Just recently, they made cross-compilation for windows binaries on linux possible. If you want to spend some time hacking it, it's probably possible. But probably easier just to get a windows machine and building a binary with it.