Trying to build a Qt 6 application but getting a Qt 5 application; Qt Creator 19 on Gentoo Linux

[JonB]

@mgoppelt
Your paths show a Qt5 installed in /usr/lib64, which is presumably supplied by your Linux OS. Quite likely it does not supply a Qt6?

So did you fetch and install (a pre-built) Qt6 yourself? Is your kit and build commands not picking that up and compiling/linking against the system's Qt5?

[mgoppelt]

Good point. Qt6 is also installed. The shared objects
/usr/lib64/libQt6Core.so.6
/usr/lib64/libQt6Gui.so.6
/usr/lib64/libQt6Widgets.so.6
are available. I'm quite sure that Gentoo builds Qt (both 5 and 6) from the sources.

[JonB]

@mgoppelt
OK, so for whatever reason even though you have picked a Qt6 kit it's compiling/linking as Qt5. Someone else will doubtless know more. Does the CMakeLists.txt for the project show anything about setting for either Qt6 or Qt5?

[mgoppelt]

CMakeLists.txt doesn't restrict the build to Qt 5 or Qt 6. There appear two variables regarding the version
${QT_VERSION_MAJOR}
${QT_VERSION}
. I will either attach CMakeLists.txt or dump it into a new reply.

[mgoppelt]

Here comes CMakeLists.txt:

cmake_minimum_required(VERSION 3.16)

project(Projekt_Muehle VERSION 0.1 LANGUAGES CXX)

set(CMAKE_AUTOUIC ON)
set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)

#set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD 20)
set(CMAKE_CXX_STANDARD_REQUIRED ON)

include_directories(${PROJECT_SOURCE_DIR})

find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Widgets)
find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS Widgets)

set(PROJECT_SOURCES
        main.cpp
        mainwindow.cpp
        mainwindow.h
        mainwindow.ui
)

if(${QT_VERSION_MAJOR} GREATER_EQUAL 6)
    qt_add_executable(Projekt_Muehle
        MANUAL_FINALIZATION
        ${PROJECT_SOURCES}
        add_args.h
        add_args.cpp
        mill_view.h mill_view.cpp
        mill_model.h mill_model.cpp
        mill_controller.h mill_controller.cpp
        player.h player.cpp
        board.h board.cpp board.ui
        token.h token.cpp token.ui
        board_label.h board_label.cpp board_label.ui
        res.qrc
    )
# Define target properties for Android with Qt 6 as:
#    set_property(TARGET Projekt_Muehle APPEND PROPERTY QT_ANDROID_PACKAGE_SOURCE_DIR
#                 ${CMAKE_CURRENT_SOURCE_DIR}/android)
# For more information, see https://doc.qt.io/qt-6/qt-add-executable.html#target-creation
else()
    if(ANDROID)
        add_library(Projekt_Muehle SHARED
            ${PROJECT_SOURCES}
        )
# Define properties for Android with Qt 5 after find_package() calls as:
#    set(ANDROID_PACKAGE_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/android")
    else()
        add_executable(Projekt_Muehle
            ${PROJECT_SOURCES}
            add_args.cpp add_args.h
            board.cpp board.h board.ui
            board_label.cpp board_label.h board_label.ui
            mill_controller.cpp mill_controller.h
            mill_model.cpp mill_model.h
            mill_view.cpp mill_view.h
            player.cpp player.h
            token.cpp token.h token.ui
        )
    endif()
endif()

target_link_libraries(Projekt_Muehle PRIVATE Qt${QT_VERSION_MAJOR}::Widgets)

# Qt for iOS sets MACOSX_BUNDLE_GUI_IDENTIFIER automatically since Qt 6.1.
# If you are developing for iOS or macOS you should consider setting an
# explicit, fixed bundle identifier manually though.
if(${QT_VERSION} VERSION_LESS 6.1.0)
  set(BUNDLE_ID_OPTION MACOSX_BUNDLE_GUI_IDENTIFIER com.example.Projekt_Muehle)
endif()
set_target_properties(Projekt_Muehle PROPERTIES
    ${BUNDLE_ID_OPTION}
    MACOSX_BUNDLE_BUNDLE_VERSION ${PROJECT_VERSION}
    MACOSX_BUNDLE_SHORT_VERSION_STRING ${PROJECT_VERSION_MAJOR}.${PROJECT_VERSION_MINOR}
    MACOSX_BUNDLE TRUE
    WIN32_EXECUTABLE TRUE
)

include(GNUInstallDirs)
install(TARGETS Projekt_Muehle
    BUNDLE DESTINATION .
    LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
    RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
)

if(QT_VERSION_MAJOR EQUAL 6)
    qt_finalize_executable(Projekt_Muehle)
endif()

[SGaist]

Hi,

Just to clear things out, can you properly build that project on the command line for each version of Qt ?

[mgoppelt]

I could only get a Qt 5 build using cmake and ninja.

First cmake:

markus@ryzen ~/Qt/Projekt_Muehle $ cmake -G Ninja -S Qt/ -B Qt/build/test_build/
-- The CXX compiler identification is GNU 15.2.1
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/c++ - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done (0.2s)
-- Generating done (0.0s)
-- Build files have been written to: /home/markus/Qt/Projekt_Muehle/Qt/build/test_build

Then ninja:

markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ ls
build.ninja  CMakeCache.txt  CMakeFiles  cmake_install.cmake
markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ ninja
[13/13] Linking CXX executable Projekt_Muehle

The files build.ninja and CMakeCache.txt only contain references to Qt 5:

markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ grep LINK_LIBRARIES build.ninja
  LINK_LIBRARIES = /usr/lib64/libQt5Widgets.so.5.15.18  /usr/lib64/libQt5Gui.so.5.15.18  /usr/lib64/libQt5Core.so.5.15.18
markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ grep -e Qt5Widgets -e Qt5Gui -e Qt5Core CMakeCache.txt
//The directory containing a CMake configuration file for Qt5Core.
Qt5Core_DIR:PATH=/usr/lib64/cmake/Qt5Core
//The directory containing a CMake configuration file for Qt5Gui.
Qt5Gui_DIR:PATH=/usr/lib64/cmake/Qt5Gui
//The directory containing a CMake configuration file for Qt5Widgets.
Qt5Widgets_DIR:PATH=/usr/lib64/cmake/Qt5Widgets
markus@ryzen ~/Qt/Projekt_Muehle/Qt/build/test_build $ grep -e Qt6Widgets -e Qt6Gui -e Qt6Core CMakeCache.txt

These two files were generated by Qt Creator prior to me using the command line:

markus@ryzen ~/Qt/Projekt_Muehle/Qt $ ls CMakeLists.txt .qtcreator/CMakeLists.txt.user 
CMakeLists.txt  .qtcreator/CMakeLists.txt.user

I don't think the second file is relevant for the command line cmake.

[mgoppelt]

Is there a way to insert a code segment without automatic coloring?

[GrecKo]

@mgoppelt said in Trying to build a Qt 6 application but getting a Qt 5 application; Qt Creator 19 on Gentoo Linux:

Is there a way to insert a code segment without automatic coloring?

```text
your log
```

[Christian Ehrlicher]

@mgoppelt And did you install the Qt6 development packages? Remove Qt5 from the CMakeLists.txt and start over with a clean build dir after you made sure the dev packages for Qt6 are installed (and even better - the dev packages for Qt5 are uninstalled).

[mgoppelt]

I have the development packages for Qt5 and Qt6. As you mentioned it works when I remove Qt5 from the following statement in CMakeLists.txt.

#find_package(QT NAMES Qt6 Qt5 REQUIRED COMPONENTS Widgets)
#find_package(QT NAMES Qt6 REQUIRED COMPONENTS Widgets)
find_package(QT NAMES Qt5 REQUIRED COMPONENTS Widgets)

The first and third line result in a Qt5 build. The second line results in a Qt6 build. The "Qt version" field in my kit seems to have no influence. I set the value to "None".

The issue is resolved. However in a weird way.