Qt 6.0 build for Raspberry Pi 4 "Opengl functionality tests failed".

[Pedro Martins]

Hi everyone,
I'm trying to build Qt6 for Raspberry Pi 4, following the Cross-Compile QT6 for Pi4.
I'm using the 64 bit image: raspios_arm64-2022-09-22.
RIght now I'm stucked with this error, can you help-me guys?

CMake Error at qtbase/cmake/QtBuildInformation.cmake:490 (message):
  Feature "opengl": Forcing to "ON" breaks its condition:

      QT_FEATURE_opengl_desktop OR QT_FEATURE_opengl_dynamic OR QT_FEATURE_opengles2

  Condition values dump:

      QT_FEATURE_opengl_desktop = "OFF"
      QT_FEATURE_opengl_dynamic = "OFF"
      QT_FEATURE_opengles2 = "OFF"

Call Stack (most recent call first):
  qtbase/cmake/QtFeature.cmake:281 (qt_configure_add_report_error)
  qtbase/cmake/QtFeature.cmake:403 (qt_feature_check_and_save_internal_value)
  qtbase/cmake/QtFeature.cmake:606 (qt_evaluate_feature)
  qtbase/cmake/QtFeature.cmake:575 (qt_feature_module_end)
  qtbase/src/CMakeLists.txt:12 (qt_feature_evaluate_features)

ERROR: Feature "opengl": Forcing to "ON" breaks its condition:
    QT_FEATURE_opengl_desktop OR QT_FEATURE_opengl_dynamic OR QT_FEATURE_opengles2
Condition values dump:
    QT_FEATURE_opengl_desktop = "OFF"
    QT_FEATURE_opengl_dynamic = "OFF"
    QT_FEATURE_opengles2 = "OFF"


ERROR: The OpenGL functionality tests failed! You might need to modify the OpenGL package search path by setting the OpenGL_DIR CMake variable to the OpenGL library's installation directory.

CMake Error at qtbase/cmake/QtBuildInformation.cmake:181 (message):
  Check the configuration messages for an error that has occurred.
Call Stack (most recent call first):
  qtbase/cmake/QtBuildInformation.cmake:21 (qt_configure_print_summary)
  CMakeLists.txt:111 (qt_print_feature_summary)

The "Toolchain.cmake" file that I used is exactly the same available on the previous link with the correct ${Target-Sysroot} and the "aarch64-linux-gnu-g++-11" Version.

I already checked the directories and everything seems good.
Do you have any ideas?

Thanks,
Pedro Martins

[Tatiana Borisova]

Hi Pedro :-)

It seems, there is a problem on configuration step. Cmake compiles a few tests on that step. To see the real error you should check following file: <buildfolder>/CMakeFiles/CMakeError.log
Could you please share the content of it? You will see error related to following tests inside file: HAVE_EGL/HAVE_GLESv2 or maybe HAVE_openg***

[H0rBIe]

Hi Pedro,

I have exactly the same problem. I also followed the instructions on your link and get the same errors at the end. Differences are that I'm using a RPI3B+ with the latest Raspbian 64 Bit Bullseye and checkout out Qt 6.4.1. I don't know if this really makes a big different if the errors are exactly the same.

Did you already find a solution?

My CMakeError.log says this:

Performing C++ SOURCE FILE Test HAVE_EGL failed with the following output:
Change Dir: /home/h0rbie/qt_buildenv/qtpi-build/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/ninja cmTC_e8779 && [1/2] Building CXX object CMakeFiles/cmTC_e8779.dir/src.cxx.o
[2/2] Linking CXX executable cmTC_e8779
FAILED: cmTC_e8779 
: && /usr/bin/aarch64-linux-gnu-g++-11 --sysroot=/home/h0rbie/qt_buildenv/rpi-sysroot -I/home/h0rbie/qt_buildenv/rpi-sysroot/usr/include -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed CMakeFiles/cmTC_e8779.dir/src.cxx.o -o cmTC_e8779  -Wl,-rpath,/home/h0rbie/qt_buildenv/rpi-sysroot  /home/h0rbie/qt_buildenv/rpi-sysroot/usr/lib/aarch64-linux-gnu/libEGL.so && :
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: /home/h0rbie/qt_buildenv/rpi-sysroot/lib/aarch64-linux-gnu/libdl.so.2: undefined reference to `_dl_addr@GLIBC_PRIVATE'
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: /home/h0rbie/qt_buildenv/rpi-sysroot/lib/aarch64-linux-gnu/libdl.so.2: undefined reference to `_dl_vsym@GLIBC_PRIVATE'
/usr/lib/gcc-cross/aarch64-linux-gnu/11/../../../../aarch64-linux-gnu/bin/ld: /home/h0rbie/qt_buildenv/rpi-sysroot/lib/aarch64-linux-gnu/libdl.so.2: undefined reference to `_dl_sym@GLIBC_PRIVATE'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.

Same goes for GLES2 etc.

BR
Tim

[mLago_46]

Hi @Pedro-Martins and everyone,

I'm running into the same issues when I run the configuration command.

I'm using a RaspberryPi 4 Model B with the following:

PRETTY_NAME="Raspbian GNU/Linux 11 (bullseye)"
NAME="Raspbian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
VERSION_CODENAME=bullseye

Regarding the Qt build I'm trying to deploy, the branch that I checkout is 6.4.0. Following the qt-wiki tutorial. Also, my host machine has the cross-compiler aarch64-linux-gnu-g++-9 and aarch64-linux-gnu-gcc-9

Sorry if it is too much of a trivial question but I want to be sure that I filled correctly the toolchain.cmake file that we have to include in the configuration. In the line that you have to specified the TARGET_SYSROOT like set(TARGET_SYSROOT /path/to/your/sysroot) , I included the path created for the sysroot of the Raspi -> rpi-sysroot, is that correct?

I will leave down the first lines of the CMakeError.log file in case someone sees something strange. Notice that I replace my home directory with $HOME myself.

Thank you in advance.

Performing C++ SOURCE FILE Test TEST_use_lld_linker failed with the following output:
Change Dir: $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-KBJUXn

Run Build Command(s):/usr/bin/ninja cmTC_b23ff && [1/2] Building CXX object CMakeFiles/cmTC_b23ff.dir/src.cxx.o
[2/2] Linking CXX executable cmTC_b23ff
FAILED: cmTC_b23ff 
: && /usr/bin/aarch64-linux-gnu-g++-9 --sysroot=$HOME/rpi-sysroot -I$HOME/rpi-sysroot/usr/include -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed    -fuse-ld=lld CMakeFiles/cmTC_b23ff.dir/src.cxx.o -o cmTC_b23ff  -Wl,-rpath,$HOME/rpi-sysroot && :
collect2: fatal error: cannot find ‘ld’
compilation terminated.
ninja: build stopped: subcommand failed.


Source file was:
int main() { return 0; }

Performing C++ SOURCE FILE Test TEST_gdb_index failed with the following output:
Change Dir: $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-aslP9l

Run Build Command(s):/usr/bin/ninja cmTC_bdb2a && [1/2] Building CXX object CMakeFiles/cmTC_bdb2a.dir/src.cxx.o
[2/2] Linking CXX executable cmTC_bdb2a
FAILED: cmTC_bdb2a 
: && /usr/bin/aarch64-linux-gnu-g++-9 --sysroot=$HOME/rpi-sysroot -I$HOME/rpi-sysroot/usr/include -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed    -Wl,--gdb-index CMakeFiles/cmTC_bdb2a.dir/src.cxx.o -o cmTC_bdb2a  -Wl,-rpath,$HOME/rpi-sysroot && :
/usr/lib/gcc-cross/aarch64-linux-gnu/9/../../../../aarch64-linux-gnu/bin/ld: unrecognised option '--gdb-index'
/usr/lib/gcc-cross/aarch64-linux-gnu/9/../../../../aarch64-linux-gnu/bin/ld: use the --help option for usage information
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.


Source file was:
int main() { return 0; }

Performing C++ SOURCE FILE Test HAVE_reduce_relocations failed with the following output:
Change Dir: $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-Rp1Nto

Run Build Command(s):/usr/bin/ninja cmTC_ccad0 && [1/2] Building CXX object CMakeFiles/cmTC_ccad0.dir/src.cxx.o
FAILED: CMakeFiles/cmTC_ccad0.dir/src.cxx.o 
/usr/bin/aarch64-linux-gnu-g++-9 --sysroot=$HOME/rpi-sysroot -DHAVE_reduce_relocations  -I$HOME/rpi-sysroot/usr/include  -fPIE -std=gnu++17 -o CMakeFiles/cmTC_ccad0.dir/src.cxx.o -c $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-Rp1Nto/src.cxx
$HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-Rp1Nto/src.cxx:2:4: error: #error Symbolic function binding on this architecture may be broken, disabling it (see QTBUG-36129).
    2 | #  error Symbolic function binding on this architecture may be broken, disabling it (see QTBUG-36129).
      |    ^~~~~
ninja: build stopped: subcommand failed.


Source file was:
 #if !(defined(__i386) || defined(__i386__) || defined(__x86_64) || defined(__x86_64__) || defined(__amd64)) || defined(__sun)
#  error Symbolic function binding on this architecture may be broken, disabling it (see QTBUG-36129).
#endif

int main(void)
{
    /* BEGIN TEST: */
    /* END TEST: */
    return 0;
}


Performing C++ SOURCE FILE Test HAVE_alloca_malloc_h failed with the following output:
Change Dir: $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-jvh1po

Run Build Command(s):/usr/bin/ninja cmTC_88f3f && [1/2] Building CXX object CMakeFiles/cmTC_88f3f.dir/src.cxx.o
FAILED: CMakeFiles/cmTC_88f3f.dir/src.cxx.o 
/usr/bin/aarch64-linux-gnu-g++-9 --sysroot=$HOME/rpi-sysroot -DHAVE_alloca_malloc_h  -I$HOME/rpi-sysroot/usr/include  -fPIE -std=gnu++17 -o CMakeFiles/cmTC_88f3f.dir/src.cxx.o -c $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-jvh1po/src.cxx
$HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-jvh1po/src.cxx: In function ‘int main()’:
$HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-jvh1po/src.cxx:6:1: error: ‘alloca’ was not declared in this scope; did you mean ‘valloc’?
    6 | alloca(1);
      | ^~~~~~
      | valloc
ninja: build stopped: subcommand failed.


Source file was:
 #include <malloc.h>

int main(void)
{
    /* BEGIN TEST: */
alloca(1);
    /* END TEST: */
    return 0;
}


Performing C++ SOURCE FILE Test HAVE_intelcet failed with the following output:
Change Dir: $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-PS6tvl

Run Build Command(s):/usr/bin/ninja cmTC_d1be3 && [1/2] Building CXX object CMakeFiles/cmTC_d1be3.dir/src.cxx.o
FAILED: CMakeFiles/cmTC_d1be3.dir/src.cxx.o 
/usr/bin/aarch64-linux-gnu-g++-9 --sysroot=$HOME/rpi-sysroot -DHAVE_intelcet  -I$HOME/rpi-sysroot/usr/include  -fPIE -std=gnu++17 -o CMakeFiles/cmTC_d1be3.dir/src.cxx.o -c $HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-PS6tvl/src.cxx
$HOME/qtpi-build/CMakeFiles/CMakeScratch/TryCompile-PS6tvl/src.cxx:5:4: error: #error Intel CET not available
    5 | #  error Intel CET not available
      |    ^~~~~
ninja: build stopped: subcommand failed.


Source file was:
 int main(void)
{
    /* BEGIN TEST: */
#if !defined(__CET__)
#  error Intel CET not available
#endif
    /* END TEST: */
    return 0;
}

etc etc ... 

[jayvae]

Hello @Pedro-Martins and everyone,

I also encountered the same issue. I am using Ubuntu22.04 (Host) with arm-linux-gnueabi-gcc-12.2.0 cross-compiler, my raspberry pi is Raspberry Pi 400 with the same CPU(BCM2711) as Raspberry 4B.

Generally i just followed the tutoria https://wiki.qt.io/Cross-Compile_Qt_6_for_Raspberry_Pi, but i am facing the opengl issue when i configured the raspi-build. The errors generated during the configure step is as follows

My configure command is as below, i am using a 32bit Raspbian, so i choose the MKSPEC "devices/linux-rasp-pi4-v3d-g++" which i am not sure whether is ok.

cmake ../qt5/ -GNinja -DCMAKE_BUILD_TYPE=Release -DINPUT_opengl=es2 -DQT_BUILD_EXAMPLES=OFF -DQT_BUILD_TESTS=OFF -DQT_HOST_PATH=$HOME/qt-host -DCMAKE_STAGING_PREFIX=$HOME/qt-raspi -DCMAKE_INSTALL_PREFIX=/usr/local/qt6 -DCMAKE_TOOLCHAIN_FILE=$HOME/qt6-arm-linux-gnueabihf-toolchain.cmake -DQT_QMAKE_TARGET_MKSPEC=devices/linux-rasp-pi4-v3d-g++ -DQT_FEATURE_xcb=ON -DFEATURE_xcb_xlib=ON -DQT_FEATURE_xlib=ON

My toolchain file is as follows:

cmake_minimum_required(VERSION 3.24)
include_guard(GLOBAL)

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)

set(TARGET_SYSROOT /usr/local/raspi_sysroot)
set(CMAKE_SYSROOT ${TARGET_SYSROOT})

set(ENV{PKG_CONFIG_PATH} $PKG_CONFIG_PATH:/usr/lib/x86_64-linux-gnu/pkgconfig)
set(ENV{PKG_CONFIG_LIBDIR} /usr/lib/pkgconfig:/usr/share/pkgconfig/:${TARGET_SYSROOT}/usr/lib/arm-linux-gnueabihf/pkgconfig:${TARGET_SYSROOT}/usr/lib/pkgconfig)
set(ENV{PKG_CONFIG_SYSROOT_DIR} ${CMAKE_SYSROOT})

# if you use other version of gcc and g++ than gcc/g++ 9, you must change the following variables
set(CMAKE_C_COMPILER arm-linux-gnueabihf-gcc)
set(CMAKE_CXX_COMPILER arm-linux-gnueabihf-g++)

# set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I${TARGET_SYSROOT}/usr/include")
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -isystem=/usr/include -isystem=/usr/local/include")
set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS}")

set(QT_COMPILER_FLAGS "-march=armv8-a")
set(QT_COMPILER_FLAGS_RELEASE "-O2 -pipe")
set(QT_LINKER_FLAGS "-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed")

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_BUILD_RPATH ${TARGET_SYSROOT})


include(CMakeInitializeConfigs)

function(cmake_initialize_per_config_variable _PREFIX _DOCSTRING)
  if (_PREFIX MATCHES "CMAKE_(C|CXX|ASM)_FLAGS")
    set(CMAKE_${CMAKE_MATCH_1}_FLAGS_INIT "${QT_COMPILER_FLAGS}")
        
    foreach (config DEBUG RELEASE MINSIZEREL RELWITHDEBINFO)
      if (DEFINED QT_COMPILER_FLAGS_${config})
        set(CMAKE_${CMAKE_MATCH_1}_FLAGS_${config}_INIT "${QT_COMPILER_FLAGS_${config}}")
      endif()
    endforeach()
  endif()


  if (_PREFIX MATCHES "CMAKE_(SHARED|MODULE|EXE)_LINKER_FLAGS")
    foreach (config SHARED MODULE EXE)
      set(CMAKE_${config}_LINKER_FLAGS_INIT "${QT_LINKER_FLAGS}")
    endforeach()
  endif()

  _cmake_initialize_per_config_variable(${ARGV})
endfunction()

set(CMAKE_LIBRARY_PATH "${CMAKE_LIBRARY_PATH}:/usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/")

set(XCB_PATH_VARIABLE ${TARGET_SYSROOT})

set(GL_INC_DIR ${TARGET_SYSROOT}/usr/include)
set(GL_LIB_DIR ${TARGET_SYSROOT}:${TARGET_SYSROOT}/usr/lib/arm-linux-gnueabihf/:${TARGET_SYSROOT}/usr:${TARGET_SYSROOT}/usr/lib)
set(OPENGL_glx_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libGLX.so)

set(EGL_INCLUDE_DIR ${GL_INC_DIR})
set(EGL_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libEGL.so)
set(OPENGL_egl_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libEGL.so)

set(OPENGL_INCLUDE_DIR ${GL_INC_DIR})
set(OPENGL_opengl_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libOpenGL.so)

set(OPENGL_glu_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libGLU.so.1)


set(GLIB_INCLUDE_DIR ${GL_INC_DIR})
set(GLIB_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libGLESv2.so)

set(GLESv2_INCLUDE_DIR ${GL_INC_DIR})
set(GLESv2_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libGLESv2.so)

set(gbm_INCLUDE_DIR ${GL_INC_DIR})
set(gbm_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libgbm.so)

set(Libdrm_INCLUDE_DIR ${GL_INC_DIR})
set(Libdrm_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libdrm.so)

set(XCB_XCB_INCLUDE_DIR ${GL_INC_DIR})
set(XCB_XCB_LIBRARY ${XCB_PATH_VARIABLE}/usr/lib/arm-linux-gnueabihf/libxcb.so)

The CMakeError.log have many compile/link error, i just post one error:

Performing C++ SOURCE FILE Test HAVE_EGL failed with the following output:
Change Dir: /home/tangjunyi/build-qt-raspi/CMakeFiles/CMakeScratch/TryCompile-MbQWqV

Run Build Command(s):/usr/bin/ninja cmTC_883dd && [1/2] Building CXX object CMakeFiles/cmTC_883dd.dir/src.cxx.o
[2/2] Linking CXX executable cmTC_883dd
FAILED: cmTC_883dd 
: && /opt/crosscompile-raspi-gcc/bin/arm-linux-gnueabihf-g++ --sysroot=/usr/local/raspi_sysroot -isystem=/usr/include -isystem=/usr/local/include -Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed CMakeFiles/cmTC_883dd.dir/src.cxx.o -o cmTC_883dd  -Wl,-rpath,/usr/local/raspi_sysroot  /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so && :
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: warning: libGLdispatch.so.0, needed by /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so, not found (try using -rpath or -rpath-link)
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchGetProcAddress'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchFini'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchLoseCurrent'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchInit'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchNewVendorID'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchCreateTable'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchCheckMultithreaded'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchForceUnpatch'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchDestroyTable'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchReset'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchMakeCurrent'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchGetABIVersion'
/opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so: undefined reference to `__glDispatchGetCurrentThreadState'
collect2: error: ld returned 1 exit status
ninja: build stopped: subcommand failed.


Source file was:

#include <EGL/egl.h>

int main(int, char **) {
    EGLint x = 0; EGLDisplay dpy = 0; EGLContext ctx = 0;
    eglDestroyContext(dpy, ctx);
}

Can anyone give me any hint or advice ?

[mLago_46]

Hi @Pedro-Martins and everyone,

[SOLVED my particular issue]

I found out what was my problem and i have to say that it was a really rookie one.

In my case, I flashed my Raspberry Pi 4 Model B using the Raspberry Pi Imager without paying attention to the architecture when I first chose the Raspberry Pi OS. It turned out that by default, it was downloading the 32-bit image, and the aarch64 cross-compiler mentioned in the Qt6 Cross Compilation is only available for the armv8. I realised that because when I tried to retrieved my architecture using $ uname -a, my output was armv7l which for me it was impossible since the Raspberry Pi 4 Model B comes with the Cortex-A72.

OUTPUT when I change the COMPILAER FLAG to armv7 in the file toolchain.cmake, like set(QT_COMPILER_FLAGS "-march=armv7"):

cc1plus: note: valid arguments are: armv8-a armv8.1-a armv8.2-a armv8.3-a
armv8.4-a armv8.5-a; did you mean ‘armv8-a’

Finally, I flashed my Rasperry Pi with the 64-bit version of the Rapsberry Pi OS and I started to follow the instructions of the tutorial again. The result was a successful configure of the build.

I hope this can help others but it was more a self-mistake than a configuration problem of openGL or cmake.

[jayvae]

Finally, I solved the opengl configure problem as follows, hope it's useful for you guys.

• Firstly, the configure error says cannnot enable OPENGL, and someone says i should look up the build-qt-raspi/CMakeFiles/CMakeError.log and search the keywords "HAVE_EGL" and "HAVE_GLESv2". And i found HAVE_EGL test failed due to a link error warning: libGLdispatch.so.0, needed by /usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/libEGL.so, not found (try using -rpath or -rpath-link) , but libGLdispatch.so.0 is just in the same directory which libEGL.so resides, so i add the compile option in toolchain file-Wl,-rpath-link=/usr/local/raspi_sysroot/usr/lib/arm-linux-gnueabihf/ to force gcc to recursively search libraries depended by the comandline linked library.(my cross-compiler is gcc-12.2 which will not by-default link the library recursively.)

• Secondly, after i repaired the opengl issue, the new error says that XCB::ICCCM, XCB::IMAGE...... can not be found, i realized something is wrong with my search-path config in the toolchain file because those XCB libraries(eg. libxcb-icccm.so, libxcb-image.so, libxcb-xxx.so ) are all in my sysroot. I carefully checked my toolchain file, and i found the environment variable PKG_CONFIG_PATH was set to a directory in Host-PC which is set(ENV{PKG_CONFIG_PATH} $PKG_CONFIG_PATH:/usr/lib/x86_64-linux-gnu/pkgconfig/) , but it should point to the sysroot directory, so i corrected the PKG_CONFIG_PATH to set(ENV{PKG_CONFIG_PATH} $PKG_CONFIG_PATH:${CMAKE_SYSROOT}/usr/lib/arm-linux-gnueabihf/pkgconfig).
  Make fuse that the xcb-xxx.pc file is in your PKG_CONFIG_PATH because the qt cmake scripts will search XCB libraries using PkgConfig.
  

• Thirdly, after i fixed the XCB issue, the new error says cannot find the X11::X11 but i already installed all the needed X11 packages listed in the tutotial, so i checked the
  FindX11.cmake script which is the cmake install dir and i found it uses the cmake native find_xxx commands to search x11 relevant files. cmake find_xxx command will by-default search the directories in the host, so it can never find the libraries in my sysroot. We can set CMAKE_LIBRARY_PATH variable to let cmake search additional directories: list(APPEND CMAKE_LIBRARY_PATH ${CMAKE_SYSROOT}/usr/lib/arm-linux-gnueabihf)
  

*Fourthly, after i eliminated all the errors, there is still an warning says md4c_DIR not set, so i installed libmd4c-dev, but the warning still exist, so i checked the FindWrapSystemMd4c.cmake which lies in qt6-sourcecode/qtbase/cmake/, it uses find_package(md4c CONFIG) command to search md4c. The find_package 's CONFIG search mode will first search for a file called md4cConfig.cmake which is actually responsible for the search job of md4c, but the md4cConfig file is also in my sysroot, So i set the CMAKE_PREFIX_PATH list(APPEND CMAKE_PREFIX_PATH "/usr/lib/arm-linux-gnueabihf/cmake") to tell cmake to search my sysroot for the cmake config file.
Make sure that the cmake config file is in your CMAKE_PREFIX_PATH.

*At last, i encountered a compile error when i started building for the Raspberry Pi 400.
error: no matching function for call to ‘min(float,std::enable_if() which points to qt6-sourcecode/qtquick3d/src/quick3dparticles/qquick3dparticleemitter.cpp

Maybe my cross-compiler's gcc version(gcc-12.2) is a little high, so it cannot match the std::min to std::min<float>, so i just simply added the explicit instantiation std::min<float> as follows:

• Ending, after i finished the build and install. I started to cross-compile the analogclock example, but during linking, an error occurs saying /opt/crosscompile-raspi-gcc/lib/gcc/arm-linux-gnueabihf/12.2.0/../../../../arm-linux-gnueabihf/bin/ld: warning: libQt6DBus.so.6, needed by /home/tangjunyi/qt-raspi/lib/libQt6Gui.so.6.4.0, not found (try using -rpath or -rpath-link). The reason is as same as the first issue during configure step. I just add the compile option -Wl,-rpath-link=$HOME/qt-raspi/lib

• appendix
  my toolchain file is as follows:

cmake_minimum_required(VERSION 3.24)
include_guard(GLOBAL)

set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)

set(CMAKE_SYSROOT /usr/local/raspi_sysroot)

set(ENV{PKG_CONFIG_PATH} $PKG_CONFIG_PATH:${CMAKE_SYSROOT}/usr/lib/arm-linux-gnueabihf/pkgconfig)
set(ENV{PKG_CONFIG_LIBDIR} ${CMAKE_SYSROOT}/usr/share/pkgconfig:${CMAKE_SYSROOT}/usr/lib/pkgconfig)
set(ENV{PKG_CONFIG_SYSROOT_DIR} ${CMAKE_SYSROOT})

# if you use other version of gcc and g++ than gcc/g++ 9, you must change the following variables
set(CMAKE_C_COMPILER arm-linux-gnueabihf-gcc)
set(CMAKE_CXX_COMPILER arm-linux-gnueabihf-g++)

# set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I${CMAKE_SYSROOT}/usr/include")
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -isystem=/usr/include -isystem=/usr/local/include -isystem=/usr/include/arm-linux-gnueabihf")
set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS}")

set(QT_COMPILER_FLAGS "-march=armv8-a")
set(QT_COMPILER_FLAGS_RELEASE "-O2 -pipe")
set(QT_LINKER_FLAGS "-Wl,-O1 -Wl,--hash-style=gnu -Wl,-rpath-link=/usr/lib/arm-linux-gnueabihf -Wl,-rpath-link=$HOME/qt-raspi/lib")

set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
set(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
set(CMAKE_BUILD_RPATH ${CMAKE_SYSROOT})


include(CMakeInitializeConfigs)

function(cmake_initialize_per_config_variable _PREFIX _DOCSTRING)
  if (_PREFIX MATCHES "CMAKE_(C|CXX|ASM)_FLAGS")
    set(CMAKE_${CMAKE_MATCH_1}_FLAGS_INIT "${QT_COMPILER_FLAGS}")
        
    foreach (config DEBUG RELEASE MINSIZEREL RELWITHDEBINFO)
      if (DEFINED QT_COMPILER_FLAGS_${config})
        set(CMAKE_${CMAKE_MATCH_1}_FLAGS_${config}_INIT "${QT_COMPILER_FLAGS_${config}}")
      endif()
    endforeach()
  endif()


  if (_PREFIX MATCHES "CMAKE_(SHARED|MODULE|EXE)_LINKER_FLAGS")
    foreach (config SHARED MODULE EXE)
      set(CMAKE_${config}_LINKER_FLAGS_INIT "${QT_LINKER_FLAGS}")
    endforeach()
  endif()

  _cmake_initialize_per_config_variable(${ARGV})
endfunction()

list(APPEND CMAKE_LIBRARY_PATH ${CMAKE_SYSROOT}/usr/lib/arm-linux-gnueabihf)
list(APPEND CMAKE_PREFIX_PATH "/usr/lib/arm-linux-gnueabihf/cmake")