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Qt Development

Everything development. From desktop and mobile to cloud. Games, tools, 3rd party libraries. Everything.
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  • This is where all the desktop OS and general Qt questions belong.
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    AndyBriceA
    @ChrisW67 said in Cache locality and QString: QString is an implicitly shared class, which is achieved through a private object held as a pointer in the QString. Even if the QString objects were consecutive in memory, in general the string data they contain is heap-allocated elsewhere. Yes, I understand that. @ChrisW67 said in Cache locality and QString: If you have a large number of QStrings of a small number of shared variants you may get a degree caching efficiency where the shared data blocks are cached. I try to do that. I am just investigating whether there is any way to be more efficient about allocating the memory for QStrings (and the data they reference) likely to be read at the same time, for less memory allocations and better cache locality. I guess you could allocate a row as a single QString (rather than a QList< QString> ) and then make each cell a QStringView into the QString. But that doesn't work well if you want to change one of the QStrings.

  • The forum for developing everything embedded: Linux, WinCE, Symbian, MeeGo... you name it.
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    JKSHJ
    @TP850 Have you installed Qt for Android yet?

  • Looking for The Bling Thing(tm)? Post here!
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    J
    Greetings, I'm trying to dynamically create qml objects that should be paired with a corresponding version of the same c++ class: Connections{ target: x function onCreateObject () { const component = Qt.createComponent("x.qml") if (component.status === Component.Ready) object = component.createObject(window) else console.log(component.errorString()) } } Using a variant of this code, I can spawn as many qml objects as I desire, but I'm unsure how to create and connect each one to their own cpp object of the same class. If I spawn qmlObj1 it should be pair with c++backend1 qmlObj2 it should be pair with c++backend2 and so on... How can I connect dynamically created qml objects to their own backend class?

  • Have a question about Qt Creator, our cross-platform IDE, or any of the other tools? Ask here!
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    J
    @Christian-Ehrlicher Noted.

  • Your Qt just doesn't want to build? Your compiler can't find the libs? Here's where you find comfort and understanding. And help.
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    M
    Hi, I am trying to set up Qtcreator to facilitate Windows development using a Linux, i.e. Ubuntu 22.04 or Ubuntu 24.04 host. I do have Qt6 development environment (Qtcreator etc...) set up and working on my Windows 10 target, but the compilation and linking steps are painfully slow on Windows and I think (from past experience) would be much faster on Linux due to Linux's faster file IO (as I am told). I have tried downloading the Qt 6.9 source code and have installed mingw-w64 cross-compiler for Win32 Win64. I followed the procedure of: https://medium.com/@vladadgad/cross-compile-qt-for-windows-on-linux-platform-57e4b71ed1aa However, I get the following fatal error: Building CXX object CMakeFiles/cmTC_5bc10.dir/src.cxx.o /usr/bin/c++ -DHAVE_ntddmodm -fPIE -std=gnu++17 -o CMakeFiles/cmTC_5bc10.dir/src.cxx.o -c /opt/Qtsource/qt5/CMakeFiles/CMakeTmp/src.cxx /opt/Qtsource/qt5/CMakeFiles/CMakeTmp/src.cxx:2:10: fatal error: windows.h: No such file or directory 2 | #include <windows.h> | ^~~~~~~~~~~ compilation terminated. It appears that the cross-compiler cannot find windows.h but locate finds it in: /usr/share/mingw-w64/include/windows.h Any ideas welcome and thanks, Phil

  • What can we say - we like games. And you can use Qt to write some. Questions? Ask here.
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    D
    I want to sincerely thank the certified recovery company that helped me reclaim my lost funds after I was scammed in an online investment scheme I had lost hope and was embarrassed to even talk about it but from the moment I contacted them they were professional responsive and incredibly supportive They reviewed my case gathered the necessary evidence and took immediate action I was skeptical at first but within a few weeks they were able to trace the funds and start the recovery process To my surprise I recovered over 80% of the money I thought was gone forever Their expertise and persistence were beyond anything I expected If you have been defrauded and think there s no way back I strongly recommend reaching out to a certified recovery service This team gave me back not just my money but my peace of mind

  • Questions about Qt WebKit and related topics? Post here!
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    JonBJ
    @Vbrg So in a word Qt only offers integrated browser with chromium/Qt web engine.

  • Discussions and questions on QtWebEngine
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    S
    Hi @Axel-Spoerl, Just checking in to see if you had a chance to look at the code I posted earlier. I'd really appreciate any insights or suggestions when you get a moment. Thanks again for your time and guidance. Regards, Soumyanil

  • You're using Qt with other languages than C++, eh? Post here!
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    G
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  • Combining Qt with 3rd party libraries or components? Ask here!
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    Axel SpoerlA
    @Dream_Helium said in Using Qt Program as a Module, but constantly get critical message: using GModule to load a Qt module just that thought scares me! Which Qt module are you loading and why with GModule? What is the expected result? g_main_context_pop_thread_default: assertion 'stack != NULL' failed As rightfully said: That error message comes from glib, not from Qt. Maybe consult the gtk forum.

  • For discussion and questions about Qt for Python (PySide & Shiboken)

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    S
    I've already tried it. It is crashing. I tried to use other versions of PySide6 and shiboken6_generator too but it didn't work .

  • Specific issues when using Qt for WebAssembly

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    S
    I think I might have a similar problem. Any update on your original issue?

  • Discussions and questions about Qt Quick Ultralite and using Qt on microcontrollers in general

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    S
    As a continuation of my earlier post regarding memory optimization, I switched the font engine from Static to Spark in my Qt for MCUs project to reduce memory footprint. I would like to understand the following: What specific library files are required when using the Spark font engine on an embedded environment? How should these libraries be linked or added to the build process to avoid runtime errors? Is there any documentation or steps specific to ensuring the Spark engine works properly during integration with an application? The build works fine on my side, but once integrated into the larger system, it fails unless the missing library is resolved. Any help or direction on resolving this and properly setting up Spark would be appreciated.

  • The forum for discussing the Qt Digital Advertising Platform

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    E
    @nayka Can I use QtDigitalAdvertising on PC applications? Or is it only allowed for use on Android or iOS mobile devices?

  • For discussion and questions about Qt Insight

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    Christian EhrlicherC
    If you modify the Qt source code then you also have to recompile the relevant Qt library. How should this work otherwise?