qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

[dziko147]

@JonB yes I checked all the outputs msg and there is not a xcb plugin :/ .

How can i install it .

[dziko147]

@JonB In my target The XCB plugin is absent .
I have this plugin :

libqeglfs.so
libqlinuxfb.so
libqminimalegl.so
libqminimal.so
libqoffscreen.so
libqvnc.so
libwebgl.so

[jsulm]

@dziko147 How did you install Qt there?

[JonB]

@dziko147
That would make your case different from every other person who has reported this error message....

Since your diagnostic output reports no error and has nothing to say about xcb, who knows what might be required?

Let me verify one thing. Your error occurs when running the app deployed to RPi, right? So to be 100% sure, you are setting the environment variable on the RPi and running the diagnostic there, aren't you??

[dziko147]

@JonB Exact . I Set environment variable QT_DEBUG_PLUGINS=1 in Qtcreator .
@jsulm from source

[jsulm]

@dziko147 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

in Qtcreator

On RPi?

[jsulm]

@dziko147 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

from source

Then probably XCB plug-in was not build because of missing dependencies. You should check config.log file to get more information.

[dziko147]

@jsulm no in Host

[jsulm]

@dziko147 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

in Host

Do you run your app from QtCreator remotely on your device?

[dziko147]

@jsulm Yes

[jsulm]

@dziko147 OK, then check config.log from your Qt build to see why XCB plug-in was not enabled.

[dziko147]

@jsulm you mean in my host machine ?

[jsulm]

@dziko147 Yes. I guess you cross compiled Qt on your host machine?

[dziko147]

@jsulm exact .
I checked my config.log
I found this :

test config.qtbase_network.tests.openssl11 succeeded
looking for library xkbcommon
Trying source 0 (type pkgConfig) of library xkbcommon ...
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --exists --silence-errors xkbcommon '>=' 0.5.0
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --modversion xkbcommon '>=' 0.5.0
> 0.8.2
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --libs-only-L xkbcommon '>=' 0.5.0
> -L/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --libs-only-l xkbcommon '>=' 0.5.0
> -lxkbcommon
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --cflags xkbcommon '>=' 0.5.0
+ cd /home/**/raspi/config.tests/xkbcommon && PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /home/**/raspi/qtbase/bin/qmake "CONFIG -= qt debug_and_release app_bundle lib_bundle" "CONFIG += shared warn_off console single_arch" "QMAKE_CFLAGS += --sysroot=/home/**/raspi/sysroot" "QMAKE_CXXFLAGS += --sysroot=/home/**/raspi/sysroot" "QMAKE_LFLAGS += --sysroot=/home/**/raspi/sysroot" -early "CONFIG += cross_compile" 'QMAKE_USE += xkbcommon' 'QMAKE_LIBS_XKBCOMMON = /home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/libxkbcommon.so' /home/**/raspi/config.tests/xkbcommon
+ cd /home/**/raspi/config.tests/xkbcommon && MAKEFLAGS= /usr/bin/make
> /home/**/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-g++ -c -march=armv8-a -mtune=cortex-a53 -mfpu=crypto-neon-fp-armv8 -mfloat-abi=hard --sysroot=/home/**/raspi/sysroot --sysroot=/home/**/raspi/sysroot -O2 -std=gnu++11 -w -fPIC  -I. -I/home/**/raspi/qt-everywhere-src-5.12.10/qtbase/mkspecs/devices/linux-rasp-pi3-g++ -o main.o main.cpp
> /home/**/raspi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian/bin/arm-linux-gnueabihf-g++ -mfloat-abi=hard --sysroot=/home/**/raspi/sysroot --sysroot=/home/**/raspi/sysroot -Wl,-O1 -Wl,-rpath-link,/home/**/raspi/sysroot/opt/vc/lib -Wl,-rpath-link,/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf -Wl,-rpath-link,/home/**/raspi/sysroot/lib/arm-linux-gnueabihf -o xkbcommon main.o   /home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/libxkbcommon.so   
 => source accepted.
test config.qtbase_gui.libraries.xkbcommon succeeded
looking for library xcb
Trying source 0 (type pkgConfig) of library xcb ...
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --exists --silence-errors xcb '>=' 1.9
pkg-config did not find package.
  => source produced no result.
Trying source 1 (type inline) of library xcb ...
None of [libxcb.so libxcb.a] found in [] and global paths.
  => source produced no result.
test config.qtbase_gui.libraries.xcb FAILED
looking for library opengl_es2
Trying source 0 (type pkgConfig) of library opengl_es2 ...
+ PKG_CONFIG_SYSROOT_DIR=/home/**/raspi/sysroot PKG_CONFIG_LIBDIR=/home/**/raspi/sysroot/usr/lib/pkgconfig:/home/**/raspi/sysroot/usr/share/pkgconfig:/home/**/raspi/sysroot/usr/lib/arm-linux-gnueabihf/pkgconfig /usr/bin/pkg-config --exists --silence-errors glesv2
pkg-config did not find package.
  => source produced no result.

[JKSH]

@dziko147 said in qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.:

I checked my config.log
I found this :

What does it say about the xcb library? Does that give you any clues?

[dziko147]

@JKSH there is no xcb plugin/lib .
So Can I install it independently

[jsulm]

@dziko147 What @JKSH means (I guess) is this:

None of [libxcb.so libxcb.a] found in [] and global paths

So, it seems that your sysroot does not contain libxcb and libxcb-dev.
Install that lib package and its dev package in your sysroot and build XCB plug-in.

[dziko147]

@jsulm there is no tutoriel or example to use it ?

[SGaist]

Hi,

The usual way is to install all the dependencies dev packages on your target and copy the root file system back on your host machine for use with your cross-compiler.