qt.qpa.plugin: Could not find the Qt platform plugin

[jsulm]

@al072072 This is asked again and again, you should use search function.
Set QT_DEBUG_PLUGINS env variable before running your app like described in https://doc.qt.io/qt-6/debug.html and check the app output or post it here.

[al072072]

@jsulm
Thank you for a quick reply, i set the "export QT_DEBUG_PLUGINS=1" in /etc/environment file, but nothing changed in application output window in Qt Creator, i am using cmake build system in Qt Creator project, i am very new to Qt could you please explaine in more details what steps to do and what am i doing wrong?

Also i put this: set(QT_DEBUG_PLUGINS 1)
in project CmakeList.txt

[jsulm]

@al072072 CMakeLists.txt is of no use here because this env variable as a runtime variable, not build time.
If you use QtCreator set it in the Run settings of your project. Or start the app from a terminal where you set it.

[al072072]

@jsulm
i run the app from terminal as you suggested with set(QT_DEBUG_PLUGINS 1) flag in my project CMakeList.txt , but it show the same output in terminal like in Qt Creator output window:

qt.qpa.plugin: Could not find the Qt platform plugin "wayland" in ""
qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""

Is it correct way to set the debug info on plugins like i did: set(QT_DEBUG_PLUGINS 1)?

[jsulm]

@al072072 said in qt.qpa.plugin: Could not find the Qt platform plugin:

as you suggested with set(QT_DEBUG_PLUGINS 1) flag in my project CMakeList.txt

I never suggested that! Please read again what I wrote...

[al072072]

@jsulm
Ok, i hope that i correctly understand you, i added this line to Run settings environment in Qt Creator: QT_DEBUG_PLUGINS=1

After i run the project again and i've got the additional string of information in my project output window in Qt Creator:

qt.core.plugin.factoryloader: ignoring "org.qt-project.Qt.QPA.QPlatformIntegrationFactoryInterface.5.3" since plugins are disabled in static builds

What does it mean?

By the way my environment is:

1. Qt Creator 13
2. Qt 6.7.0 (static build)
3. Ubuntu 24.04 LTS

[jsulm]

@al072072 Just realized that the plug-ins were not found. My suggestion was for cases where plug-ins are found but fail to load, so useless for your problem.

The error messages in your first post clearly say that these plug-ins where not found. Check whether they were built (configure script says what is enabled and what not).

Also, do you really need a static Qt build?

This is not enough:

sudo apt install libxcb-xinerama0
sudo apt install qt6-wayland

you also need the dev packages.

[al072072]

@jsulm
I am sure this plugins (xcb,wayland) were not built becase i checked the plugins platfroms folder and there is no plugins files inside of it. I am not sure about the static build (just want to set it up like in my windows project) and run it as a static (there is no problems with dynamic build). Thank you for information i will try to find a dev libs and install them. What should i do after installing the dev libs? It seems like i need to rebuild the Qt library, is it possible to force disabling the plugins use during the build configuration process? I already tried -skip xcb and -skip wayland, but it didn't help still got the errors when Run the app.

[jsulm]

@al072072 said in qt.qpa.plugin: Could not find the Qt platform plugin:

I already tried -skip xcb and -skip wayland, but it didn't help still got the errors when Run the app.

Well, for graphical Qt applications you need at least one backend. On Linux usually xcb or wayland. So, first decide what you need and then disable what you do not need.
"but it didn't help still got the errors when Run the app" - of course, how should your app run without any backend?

[al072072]

@jsulm
i also tried to make a configuration without skipping both of (xcb and wayland) - the same result. I've checked the dev packages for :

sudo apt install libxcb-xinerama0-dev
sudo apt install qt6-wayland-dev

packages are installed.

Now i reconfigure the build with the following configuration string:

./configure -release -static -static-runtime -opensource -confirm-license -nomake examples -nomake tests -prefix /home/Qt/6.7.0/static_gcc_64

Here is configuration output:

-- Configure summary:

Building for: linux-g++ (x86_64, CPU features: )
Compiler: gcc 11.4.0
Build options:
  Mode ................................... release
  Optimize release build for size ........ no
  Fully optimize release builds (-O3) .... no
  Building shared libraries .............. no
  Using ccache ........................... no
  Unity Build ............................ no
  Using new DTAGS ........................ yes
  Relocatable ............................ no
  Using precompiled headers .............. yes
  Using Link Time Optimization (LTCG) .... no
  Using Intel CET ........................ yes
  Target compiler supports:
    x86 Intrinsics ....................... Basic VAES AVX512VBMI2
  Sanitizers:
    Addresses ............................ no
    Threads .............................. no
    Memory ............................... no
    Fuzzer (instrumentation only) ........ no
    Undefined ............................ no
  Build parts ............................ libs tools
  Install examples sources ............... no
Qt modules and options:
  Qt Concurrent .......................... yes
  Qt D-Bus ............................... yes
  Qt D-Bus directly linked to libdbus .... no
  Qt Gui ................................. yes
  Qt Network ............................. yes
  Qt PrintSupport ........................ yes
  Qt Sql ................................. yes
  Qt Testlib ............................. yes
  Qt Widgets ............................. yes
  Qt Xml ................................. yes
Support enabled for:
  Using pkg-config ....................... no
  Using vcpkg ............................ no
  udev ................................... no
  OpenSSL ................................ no
    Qt directly linked to OpenSSL ........ no
  OpenSSL 1.1 ............................ no
  OpenSSL 3.0 ............................ no
  Using system zlib ...................... no
  Zstandard support ...................... no
  Thread support ......................... yes
Common build options:
  Linker can resolve circular dependencies  yes
Qt Core:
  backtrace .............................. yes
  DoubleConversion ....................... yes
    Using system DoubleConversion ........ no
  CLONE_PIDFD support in forkfd .......... yes
  GLib ................................... no
  ICU .................................... no
  Using system libb2 ..................... no
  Built-in copy of the MIME database ..... yes
  Application permissions ................ yes
  Defaulting legacy IPC to POSIX ......... no
  Tracing backend ........................ <none>
  OpenSSL based cryptographic hash ....... no
  Logging backends:
    journald ............................. no
    syslog ............................... no
    slog2 ................................ no
  PCRE2 .................................. yes
    Using system PCRE2 ................... no
Qt Sql:
  SQL item models ........................ yes
Qt Network:
  getifaddrs() ........................... no
  IPv6 ifname ............................ no
  libproxy ............................... no
  Linux AF_NETLINK ....................... yes
  DTLS ................................... no
  OCSP-stapling .......................... no
  SCTP ................................... no
  Use system proxies ..................... yes
  GSSAPI ................................. no
  Brotli Decompression Support ........... no
  qIsEffectiveTLD() ...................... yes
    Built-in publicsuffix database ....... yes
    System publicsuffix database ......... yes
Core tools:
  Android deployment tool ................ yes
  macOS deployment tool .................. no
  Windows deployment tool ................ no
  qmake .................................. yes
Qt Gui:
  Accessibility .......................... yes
  FreeType ............................... yes
    Using system FreeType ................ no
  HarfBuzz ............................... yes
    Using system HarfBuzz ................ no
  Fontconfig ............................. no
  Image formats:
    GIF .................................. yes
    ICO .................................. yes
    JPEG ................................. yes
      Using system libjpeg ............... no
    PNG .................................. yes
      Using system libpng ................ no
  Text formats:
    HtmlParser ........................... yes
    CssParser ............................ yes
    OdfWriter ............................ yes
    MarkdownReader ....................... yes
      Using system libmd4c ............... no
    MarkdownWriter ....................... yes
  EGL .................................... yes
  OpenVG ................................. no
  OpenGL:
    Desktop OpenGL ....................... yes
    OpenGL ES 2.0 ........................ no
    OpenGL ES 3.0 ........................ no
    OpenGL ES 3.1 ........................ no
    OpenGL ES 3.2 ........................ no
  Vulkan ................................. no
  Session Management ..................... yes
Features used by QPA backends:
  evdev .................................. yes
  libinput ............................... no
  HiRes wheel support in libinput ........ no
  INTEGRITY HID .......................... no
  mtdev .................................. no
  tslib .................................. no
  xkbcommon .............................. yes
  X11 specific:
    XLib ................................. yes
    XCB Xlib ............................. no
    EGL on X11 ........................... yes
    xkbcommon-x11 ........................ no
    xcb-sm ............................... no
QPA backends:
  DirectFB ............................... no
  EGLFS .................................. yes
  EGLFS details:
    EGLFS OpenWFD ........................ no
    EGLFS i.Mx6 .......................... no
    EGLFS i.Mx6 Wayland .................. no
    EGLFS RCAR ........................... no
    EGLFS EGLDevice ...................... no
    EGLFS GBM ............................ no
    EGLFS VSP2 ........................... no
    EGLFS Mali ........................... no
    EGLFS Raspberry Pi ................... no
    EGLFS X11 ............................ no
  LinuxFB ................................ yes
  VNC .................................... yes
  VK_KHR_display ......................... no
  QNX:
    lgmon ................................ no
    IMF .................................. no
  XCB:
    Using system-provided xcb-xinput ..... no
    GL integrations:
      GLX Plugin ......................... no
        XCB GLX .......................... no
      EGL-X11 Plugin ..................... no
  Windows:
    Direct 2D ............................ no
    Direct 2D 1.1 ........................ no
    DirectWrite .......................... no
    DirectWrite 3 ........................ no
Qt Widgets:
  GTK+ ................................... no
  Styles ................................. Fusion Windows
Qt Testlib:
  Tester for item models ................. yes
  Batch tests ............................ no
Qt PrintSupport:
  CUPS ................................... no
Qt Sql Drivers:
  DB2 (IBM) .............................. no
  InterBase .............................. no
  MySql .................................. no
  OCI (Oracle) ........................... no
  ODBC ................................... no
  PostgreSQL ............................. no
  SQLite ................................. yes
    Using system provided SQLite ......... no
  Mimer .................................. no
Further Image Formats:
  JasPer ................................. no
  MNG .................................... no
  TIFF ................................... yes
    Using system libtiff ................. no
  WEBP ................................... yes
    Using system libwebp ................. no
Qt QML:
  QML network support .................... yes
  QML debugging and profiling support .... yes
  QML just-in-time compiler .............. yes
  QML XML http request ................... yes
  QML Locale ............................. yes
  QML SSL support ........................ no
Qt QML:
  QML network support .................... yes
  QML debugging and profiling support .... yes
  QML just-in-time compiler .............. yes
  QML XML http request ................... yes
  QML Locale ............................. yes
  QML SSL support ........................ no
Qt QML Models:
  QML list model ......................... yes
  QML delegate model ..................... yes
Qt Quick:
  AnimatedImage item ..................... yes
  Canvas item ............................ yes
  Support for Qt Quick Designer .......... yes
  Flipable item .......................... yes
  GridView item .......................... yes
  ListView item .......................... yes
  TableView item ......................... yes
  TreeView item .......................... yes
  Path support ........................... yes
  PathView item .......................... yes
  Positioner items ....................... yes
  Repeater item .......................... yes
  ShaderEffect item ...................... yes
  Sprite item ............................ yes
Qt Quick Templates 2:
  Hover support .......................... yes
  Multi-touch support .................... yes
  Calendar support ....................... yes
Qt Quick Controls 2:
  Styles ................................. Basic Fusion Imagine Material Universal
QtQuick3D:
  Assimp ................................. yes
  System Assimp .......................... no
Qt Multimedia:
  Spatial Audio .......................... yes
  Spatial Audio (Quick3D) ................ yes
  Low level Audio Backend:
    ALSA (experimental) .................. no
    PulseAudio ........................... no
    MMRenderer ........................... no
    CoreAudio ............................ no
    Windows Media SDK .................... no
    Open SLES (Android) .................. no
    Web Assembly ......................... no
  Plugin:
    GStreamer 1.0 ........................ no
    FFmpeg ............................... no
    MMRenderer ........................... no
    AVFoundation ......................... no
    Windows Media Foundation ............. no
  Hardware acceleration and features:
    Video for Linux ...................... yes
    VAAPI support ........................ no
    Linux DMA buffer support ............. yes
    VideoToolbox ......................... no
Qt 3D:
  Assimp ................................. yes
  System Assimp .......................... no
  Aspects:
    Render aspect ........................ yes
    Input aspect ......................... yes
    Logic aspect ......................... yes
    Animation aspect ..................... yes
    Extras aspect ........................ yes
Qt 3D APIs:
  Vulkan ................................. no
Qt 3D Renderers:
  OpenGL Renderer ........................ yes
  RHI Renderer ........................... yes
Qt3D Geometry Loaders:
  Autodesk FBX ........................... no
Qt 5 Compatibility Libraries:
  iconv .................................. yes
Qt Charts Types:
  Area Chart ............................. yes
  Line Chart ............................. yes
  Spline Chart ........................... yes
  Scatter Chart .......................... yes
  Bar Chart .............................. yes
  Pie Chart .............................. yes
  Boxplot Chart .......................... yes
  Candlestick Chart ...................... yes
Qt Axis Types:
  DateTime Axis .......................... yes
Qt Bluetooth:
  BlueZ .................................. no
  BlueZ Low Energy ....................... no
  Linux Crypto API ....................... no
  WinRT Bluetooth API .................... no
Qt Graphs Support:
  2D Graphs .............................. yes
  3D Graphs .............................. yes
Qt Graphs 3D:
  Bars3D ................................. yes
  Scatter3D .............................. yes
  Surface3D .............................. yes
Serial Port:
  ntddmodm ............................... no
Qt Tools:
  Qt Assistant ........................... yes
  libclang found ......................... no
  Clang-based lupdate parser ............. no
  Qt Designer ............................ yes
  Qt Distance Field Generator ............ yes
  Qt Linguist ............................ yes
  pixeltool .............................. yes
  qdbus .................................. yes
  QDoc ................................... no
  Qt Attributions Scanner ................ yes
  qtdiag ................................. yes
  qtplugininfo ........................... yes
WebEngine Repository Build Options:
  Build Ninja ............................ no
  Build Gn ............................... yes
  Jumbo Build ............................ yes
  Developer build ........................ no
  Build QtWebEngine Modules:
    Build QtWebEngineCore ................ no
    Build QtWebEngineWidgets ............. no
    Build QtWebEngineQuick ............... no
  Build QtPdf Modules:
    Build QtPdfWidgets ................... no
    Build QtPdfQuick ..................... no
  Optional system libraries:
    re2 .................................. no
    icu .................................. no
    libwebp, libwebpmux and libwebpdemux . no
    opus ................................. no
    ffmpeg ............................... no
    libvpx ............................... no
    snappy ............................... no
    glib ................................. no
    zlib ................................. no
    minizip .............................. no
    libevent ............................. no
    libxml2 and libxslt .................. no
    lcms2 ................................ no
    png .................................. no
    tiff ................................. no
    jpeg ................................. no
    libopenjpeg2 ......................... no
    harfbuzz ............................. no
    freetype ............................. no
    libpci ............................... no
  Qt 3rdparty libs:
    qtfreetype ........................... yes
    qtharfbuzz ........................... yes
    qtpng ................................ yes
    qtjpeg ............................... yes
    qtzlib ............................... yes
  Qt Protobuf:
    Qt Core types support ................ no
    Qt Gui types support ................. no
    Well-known types support ............. no
  Qt Protobuf tools:
    Qt Protobuf generator ................ no
  Qt GRPC:
    gRPC support ......................... yes
    QML gRPC support ..................... yes
  Qt GRPC tools:
    Qt GRPC generator .................... no
  sql storage ............................ yes
  sql with zlib compression .............. no
  sql with zstd compression .............. no
  Qt Opcua:
    Open62541 ............................ yes
    Support for namespace 0 NodeId names . yes
    Internal code generator .............. no
    Open62541 security support ........... no
    Support for global discovery server .. no
    Data type code generator ............. yes
  Qt Remote Objects:
    High Availability Manager (ham) ...... no
  Qt Scxml:
    ECMAScript data model for QtScxml .... yes
  Qt Sensors:
    sensorfw ............................. no
    sensorfw_enabled_with_cmake .......... no
  Qt SerialBus:
    Socket CAN ........................... yes
    Socket CAN FD ........................ yes
    SerialPort Support ................... yes
  Qt TextToSpeech:
    Flite ................................ no
    Flite with ALSA ...................... no
    Speech Dispatcher .................... no
  Qt Virtualkeyboard:
    Desktop integration .................. yes
    Built-in layouts ..................... yes
    Key navigation ....................... no
    Retro style as default ............... no
    Sensitive Debug ...................... no
    Cerence .............................. no
      Static Linking ..................... no
      Handwriting ........................ no
        Alphabetic ....................... no
        CJK .............................. no
      XT9 ................................ no
        XT9 Debug ........................ no
        XT9 9-key layouts ................ no
      Bundle resources ................... no
        Handwriting ...................... no
        XT9 .............................. no
    Hunspell ............................. no
      Using Hunspell copy from 3rdparty/ . no
    OpenWnn .............................. yes
    MyScript ............................. no
    Example HWR .......................... no
    Language support enabled for:
      Arabic ............................. yes
      Bulgarian .......................... yes
      Czech .............................. yes
      Danish ............................. yes
      German ............................. yes
      Greek .............................. yes
      English GB ......................... yes
      English US ......................... yes
      Spanish ............................ yes
      Spanish Mexico ..................... yes
      Estonian ........................... yes
      Farsi .............................. yes
      Finnish ............................ yes
      French Canada ...................... yes
      French France ...................... yes
      Hebrew ............................. yes
      Hindi .............................. yes
      Croatian ........................... yes
      Hungarian .......................... yes
      Indonesian ......................... yes
      Italian ............................ yes
      Japanese ........................... yes
      Korean ............................. yes
      Malay .............................. yes
      Norwegian .......................... yes
      Dutch .............................. yes
      Polish ............................. yes
      Portuguese Brazil .................. yes
      Portuguese Portugal ................ yes
      Romanian ........................... yes
      Russian ............................ yes
      Slovak ............................. yes
      Slovenian .......................... yes
      Albanian ........................... yes
      Serbian ............................ yes
      Swedish ............................ yes
      Thai ............................... yes
      Turkish ............................ yes
      Ukrainian .......................... yes
      Vietnamese ......................... yes
      Simplified Chinese ................. yes
      Traditional Chinese ................ yes
      HongKong Chinese ................... no
    Traditional chinese input methods:
      Zhuyin ............................. yes
      Cangjie ............................ yes
 

Note: Using static linking will disable the use of dynamically loaded plugins. Make sure to import all needed static plugins, or compile needed modules into the library.
Note: Hunspell in Qt Virtual Keyboard is not enabled. Spelling correction will not be available.

WARNING: Feature static_runtime is insignificant in this configuration, ignoring related command line option(s).
WARNING: No backend for low level audio found.
WARNING: QDoc will not be compiled, probably because clang's C and C++ libraries could not be located. This means that you cannot build the Qt documentation.
You may need to set CMAKE_PREFIX_PATH or LLVM_INSTALL_DIR to the location of your llvm installation.
Other than clang's libraries, you may need to install another package, such as clang itself, to provide the ClangConfig.cmake file needed to detect your libraries. Once this
file is in place, the configure script may be able to detect your system-installed libraries without further environment variables.
On macOS, you can use Homebrew's llvm package.
You will also need to set the FEATURE_clang CMake variable to ON to re-evaluate this check.
WARNING: Clang-based lupdate parser will not be available. LLVM and Clang C++ libraries have not been found.
You will need to set the FEATURE_clangcpp CMake variable to ON to re-evaluate this check.
WARNING: QtWebEngine won't be built. Static build is not supported.
WARNING: QtPdf won't be built. node.js version 14 or later is required.
WARNING: SensorFW support currently not enabled with cmake

-- 

Qt is now configured for building. Just run 'cmake --build . --parallel'

Once everything is built, you must run 'cmake --install .'
Qt will be installed into '/home/Qt/6.7.0/static_gcc_64'

To configure and build other Qt modules, you can use the following convenience script:
        /home/Qt/6.7.0/static_gcc_64/bin/qt-configure-module

If reconfiguration fails for some reason, try removing 'CMakeCache.txt' from the build directory


-- Configuring done
-- Generating done
-- Build files have been written to: /home/alex/Qt/6.7.0/Src

Could you please take a look on it and advice me to do any additional steps for configuration that i will be able to run the static version of app after build? thank you

[Christian Ehrlicher]

@al072072 said in qt.qpa.plugin: Could not find the Qt platform plugin:

X11 specific:
XLib ................................. yes
XCB Xlib ............................. no
EGL on X11 ........................... yes
xkbcommon-x11 ........................ no
xcb-sm ............................... no

How to make it more obvoius that there is some X11 stuff missing?

[al072072]

@Christian-Ehrlicher said in qt.qpa.plugin: Could not find the Qt platform plugin:

How to make it more obvoius that there is some X11 stuff missing?

Thank you for reply, i am very new to Qt excuse me for a nubies questions, but could you please advice what additional libraries should be installed to ubuntu environment to make a plugins support is ON?

[jsulm]

@al072072 Look into config.log file which is generated by configure script - you will find exact information about missing libs.

[al072072]

@jsulm
there is no config.log file in configuration dir where the ./configure file is located

[jsulm]

@al072072 said in qt.qpa.plugin: Could not find the Qt platform plugin:

where the ./configure file is located

The log file is in the build folder, not where configure script is located...

[al072072]

@jsulm
Thank you very much for replies and your time, finally i found a solution to build a static Qt lib using this approach: https://forum.qt.io/topic/115827/build-on-linux-qt-xcb-option/12