Important: Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

Definitive guide to building source from downloaded .run file?



  • Now qmake runs without error on my application pro file. Not only do I have to directly execute the qmake that was built as part of the source download, but my $PATH must include other binary executables that were also built. So I ran 'make install' on the Qt source, which installed things in /usr/local/Qt5.14.2/bin, added that directory to PATH, and now qmake generates a Makefile.



  • @Tom-asso said in Definitive guide to building source from downloaded .run file?:

    Now qmake runs without error on my application pro file. Not only do I have to directly execute the qmake that was built as part of the source download, but my $PATH must include other binary executables that were also built. So I ran 'make install' on the Qt source, which installed things in /usr/local/Qt5.14.2/bin, added that directory to PATH, and now qmake generates a Makefile.

    Hooray! Yes, that all sounds correct. Good on you for solving it, and thanks for posting the whole solution!



  • But now a new problem. After running qmake on my project .pro file, generating a Makefile, then running 'make' to build my application, my application executable ("mbgrdviz-2") does not run:

    % ./mbgrdviz-2
    qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""
    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
    
    Available platform plugins are: eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, webgl.
    
    Aborted (core dumped)
    

    Anyone know why? I built the Qt sources with configure, make, make install. Then built my app with qmake then make. What am I missing?



  • I think you now need this next tip (referring back again to the Linux getting started notes from my own team):

    If the app fails with a message such as qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "/home/daniel/Qt/5.14.0/gcc_64/plugins" even though it was found., you need to set QT_QPA_PLATFORM_PLUGIN_PATH to the correct location. And when you set that, you must ensure that LD_LIBRARY_PATH also points to the same Qt build.

     export QT_QPA_PLATFORM_PLUGIN_PATH="$(pwd)/build_qt_binaries/qt5_opt_install/plugins/platforms
     export LD_LIBRARY_PATH="$(pwd)/build_qt_binaries/qt5_opt_install/lib:$LD_LIBRARY_PATH"
    

    ^^ obviously you need to adjust the paths a bit, since on your setup the plugins and libs are not under "build_qt_binaries/qt5_opt_install"



  • @KH-219Design - I did 'make install' after building the source, which put stuff in /usr/local/Qt5.14.2, including in /usr/local/Qt5.14.2/ilbs and /usr/local/Qt5.14.2/plugins/platforms.

    So:

    % export LD_LIBRARY_PATH=/usr/local/Qt-5.14.2/lib
    % export QT_QPA_PLATFORM_PLUGIN_PATH=/usr/local/Qt-5.14.2/plugins/platforms
    

    But my app still fails to find the xcb plugin, and I can see why because 'make' of the Qt source code didn't build an xcb plugin and it wasn't installed:

    ls /usr/local/Qt-5.14.2/plugins/platforms
    libqeglfs.so       libqminimal.so    libqwayland-egl.so
    libqlinuxfb.so     libqoffscreen.so  libqwayland-generic.so
    libqminimalegl.so  libqvnc.so        libqwebgl.so
    

    I.e. there is no "libxcb.so" or anything like that in there, although I see there are many source files with names containing "xcb". Per this page I tried running 'configure' with the -qt-xcb option:

    ./configure -qt-xcb
    [...]
    ERROR: Feature 'xcb' was enabled, but the pre-condition 'features.thread && features.xkbcommon && libs.xcb' failed.
    

    Not sure what that means...
    I tried to manually build libxcb within the Qt source directories - that built libxcb_static.a, but then failed:

    % cd qtbase/src/plugins/platforms/xcb
    % qmake   # Build Makefile from xcb.pro
    % make
    [...]
    ar cqs ../../../../../lib/libxcb-static.a .obj/xfixes.o .obj/randr.o .obj/shm.o .obj/sync.o .obj/render.o .obj/shape.o .obj/xkb.o .obj/xinerama.o .obj/xinput.o .obj/xcb_aux.o .obj/atoms.o .obj/event.o .obj/xcb_image.o .obj/keysyms.o .obj/util.o .obj/icccm.o
    make[1]: Leaving directory '/home/oreilly/qt-download/qt-everywhere-src-5.14.2/qtbase/src/plugins/platforms/xcb/xcb-static'
    ( test -e Makefile.xcb_qpa_lib || /home/oreilly/qt-download/qt-everywhere-src-5.14.2/qtbase/bin/qmake -o Makefile.xcb_qpa_lib /home/oreilly/qt-download/qt-everywhere-src-5.14.2/qtbase/src/plugins/platforms/xcb/xcb_qpa_lib.pro ) && make -f Makefile.xcb_qpa_lib 
    Project ERROR: Could not find feature xcb-xinput.
    Makefile:90: recipe for target 'sub-xcb_qpa_lib-pro-make_first-ordered' failed
    make: *** [sub-xcb_qpa_lib-pro-make_first-ordered] Error 3
    

    Man, I have no idea how you guys are able to get this to work ;-)



  • Man, I have no idea how you guys are able to get this to work ;-)

    Heh. I think it is like eating spicy food. First you develop a tolerance for it gradually, then you actually start to crave and enjoy it ;)

    Hmmm....

    I've got 2 thoughts now.

    The most direct attack would be to get further into this:

    ./configure -qt-xcb
    [...]
    ERROR: Feature 'xcb' was enabled, but the pre-condition 'features.thread && features.xkbcommon && libs.xcb' failed.
    

    That seems to me like a good approach, and there must be more info "somewhere" about that failure. Isn't there a config.log file somewhere, as an output from the configure? Its contents should look roughly like:

    ... truncated ...
    
    executing config test linuxfb
    + cd /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/linuxfb && PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /opt/repositories/fc-build-01/qt5_dbg_configuration/qtbase/bin/qmake "CONFIG -= qt debug_and_release app_bundle lib_bundle" "CONFIG += shared warn_off console single_arch" "QMAKE_CFLAGS += --sysroot=/" "QMAKE_CXXFLAGS += --sysroot=/" "QMAKE_LFLAGS += --sysroot=/" -early "CONFIG += cross_compile" /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/linuxfb
    + cd /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/linuxfb && MAKEFLAGS= /usr/bin/make
    > g++ -c -pipe --sysroot=/ --sysroot=/ -g -w -fPIC  -I. -I/opt/repositories/qt5_sources/qtbase/mkspecs/linux-g++ -o main.o main.cpp
    > g++ --sysroot=/ --sysroot=/ -o linuxfb main.o      
    test config.qtbase_gui.tests.linuxfb succeeded
    looking for library mtdev
    Trying source 0 (type pkgConfig) of library mtdev ...
    + PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /usr/bin/pkg-config --exists --silence-errors mtdev
    + PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /usr/bin/pkg-config --modversion mtdev
    > 1.1.5
    + PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /usr/bin/pkg-config --libs-only-L mtdev
    + PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /usr/bin/pkg-config --libs-only-l mtdev
    > -lmtdev
    + PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /usr/bin/pkg-config --cflags mtdev
    + cd /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/mtdev && PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /opt/repositories/fc-build-01/qt5_dbg_configuration/qtbase/bin/qmake "CONFIG -= qt debug_and_release app_bundle lib_bundle" "CONFIG += shared warn_off console single_arch" "QMAKE_CFLAGS += --sysroot=/" "QMAKE_CXXFLAGS += --sysroot=/" "QMAKE_LFLAGS += --sysroot=/" -early "CONFIG += cross_compile" 'QMAKE_USE += mtdev' 'QMAKE_LIBS_MTDEV = -lmtdev' /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/mtdev
    + cd /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/mtdev && MAKEFLAGS= /usr/bin/make
    > g++ -c -pipe --sysroot=/ --sysroot=/ -g -w -fPIC  -I. -I/opt/repositories/qt5_sources/qtbase/mkspecs/linux-g++ -o main.o main.cpp
    > g++ --sysroot=/ --sysroot=/ -o mtdev main.o   -lmtdev   
     => source accepted.
    test config.qtbase_gui.libraries.mtdev succeeded
    looking for library openvg
    Trying source 0 (type pkgConfig) of library openvg ...
    + PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /usr/bin/pkg-config --exists --silence-errors vg
    pkg-config did not find package.
      => source produced no result.
    Trying source 1 (type makeSpec) of library openvg ...
    VG/openvg.h not found in [] and global paths.
      => source produced no result.
    test config.qtbase_gui.libraries.openvg FAILED
    executing config test qpa_default_platform
    test config.qtbase_gui.tests.qpa_default_platform gave result xcb
    looking for library harfbuzz
    Trying source 0 (type inline) of library harfbuzz ...
    + cd /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/harfbuzz && PKG_CONFIG_SYSROOT_DIR=/ PKG_CONFIG_LIBDIR=//usr/lib/pkgconfig://usr/share/pkgconfig://usr/lib/x86_64-linux-gnu/pkgconfig /opt/repositories/fc-build-01/qt5_dbg_configuration/qtbase/bin/qmake "CONFIG -= qt debug_and_release app_bundle lib_bundle" "CONFIG += shared warn_off console single_arch" "QMAKE_CFLAGS += --sysroot=/" "QMAKE_CXXFLAGS += --sysroot=/" "QMAKE_LFLAGS += --sysroot=/" -early "CONFIG += cross_compile" 'QMAKE_USE += harfbuzz' 'QMAKE_LIBS_HARFBUZZ = -lharfbuzz' /opt/repositories/fc-build-01/qt5_dbg_configuration/config.tests/harfbuzz
    
    ... truncated ...
    

    Hopefully there would be a more precise answer in there as to exactly what steps caused "features.xkbcommon" (and the others) to fail.

    A less direct attack would be:

    ... if we assume the configure failed because you simply need more dev headers of more cascading dependencies to be available on your machine for the compiler to use...

    Then if you try this and things get installed:

    sudo sed -i -- 's/#deb-src/deb-src/g' /etc/apt/sources.list
    sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
    sudo apt-get update
    
    sudo apt-get build-dep qt5-default
    

    Then just try ./configure -qt-xcb again (or even a bare ./configure), and this time configure should be able to detect more build dependencies on the system.



  • @KH-219Design - I will try that. But in the meantime I actually built shared library libxcb.so "by hand" (since 'make' failed) and copied it into the plugins/platforms directory:

    % g++ -shared -o libxcb.so *.o
    % sudo cp libxcb.so /usr/shared/Qt5.14.2/plugins/platforms/.
    

    I then rebuilt my app and tried to run it:

    % qmake
    % make clean
    % make
    % ./mbgrdviz-2
    qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "/usr/local/Qt-5.14.2/plugins/platforms"
    This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
    
    Available platform plugins are: eglfs (from /usr/local/Qt-5.14.2/plugins/platforms), linuxfb (from /usr/local/Qt-5.14.2/plugins/platforms), minimal (from /usr/local/Qt-5.14.2/plugins/platforms), minimalegl (from /usr/local/Qt-5.14.2/plugins/platforms), offscreen (from /usr/local/Qt-5.14.2/plugins/platforms), vnc (from /usr/local/Qt-5.14.2/plugins/platforms), wayland-egl (from /usr/local/Qt-5.14.2/plugins/platforms), wayland (from /usr/local/Qt-5.14.2/plugins/platforms), webgl (from /usr/local/Qt-5.14.2/plugins/platforms), eglfs, linuxfb, minimal, minimalegl, offscreen, vnc, wayland-egl, wayland, webgl.
    

    So although the library I built, libxcb.so, is in /usr/shared/Qt5.14.2/plugsins/platforms, it is not detected as a "plugin" - why might that be? Is there some special step to "register" a plugin?
    Thanks!



  • @KH-219Design - taking the "direct attack" by looking into the config.log file... I just installed the ubuntu package for xkbcommon (apt install libxkbcommon-dev), verified presence of /usr/include/xkbcommon/xkbcommon.h. Then re-ran "./configure -qt-xcb" which again gives "ERROR: Feature 'xcb' was enabled, but the pre-condition 'features.thread && features.xkbcommon && libs.xcb' failed." I look in config.logs and see these lines:

    loaded result for library config.qtbase_gui.libraries.xkbcommon
    Trying source 0 (type pkgConfig) of library xkbcommon ...
    + /usr/bin/pkg-config --exists --silence-errors xkbcommon '>=' 0.5.0
    pkg-config did not find package.
      => source produced no result.
    Trying source 1 (type inline) of library xkbcommon ...
    xkbcommon/xkbcommon.h not found in [] and global paths.
      => source produced no result.
    test config.qtbase_gui.libraries.xkbcommon FAILED
    

    So configure cannot find /usr/include/xkbcommon/xkbcommon.h - even though it exists?



  • regarding the question about not finding a plugin... I'm not really sure, but you might try running ldd on the so you built.

    if ldd produces anything like either of these, then you would be missing load-time dependencies for your so:

    bad outcome #1:

    ldd libQt5Gui.so.5.14.0
    # this message about the version not found is bad:
    ./libQt5Gui.so.5.14.0: /usr/lib/x86_64-linux-gnu/libQt5Core.so.5: version `Qt_5.14' not found (required by ./libQt5Gui.so.5.14.0)
    	linux-vdso.so.1 (0x00007ffe7e3e5000)
    	libQt5Core.so.5 => /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 (0x00007f30cdac6000)
    	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f30cd8a7000)
    
    

    bad outcome #2 ("not found"):

    ldd libQt5Gui.so.5.14.0
    	linux-vdso.so.1 (0x00007ffc16ba5000)
    	libQt5Core.so.5 => not found                  # <-- anything "not found" is a problem
    	libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f624ce6a000)
    	libGL.so.1 => /usr/lib/x86_64-linux-gnu/libGL.so.1 (0x00007f624cbde000)
    	libharfbuzz.so.0 => /usr/lib/x86_64-linux-gnu/libharfbuzz.so.0 (0x00007f624c940000)
    
    

    (Note: I ran ldd on libQt5Gui only for the sake of generating sample output. I am not suggesting you ldd libQt5Gui, but rather that you ldd libxcb.so )

    Regarding your results from the direct attack on configure failures:

    + /usr/bin/pkg-config --exists --silence-errors xkbcommon '>=' 0.5.0
    pkg-config did not find package.
    

    You could run /usr/bin/pkg-config --libs xkbcommon and see what you get.

    You could also run apt-cache show libxkbcommon-dev and make sure the version is greater than 0.5.0

    Racking my brain trying to think what else...

    I guess just make sure any "left over cruft" from previous configure attempts are interfering... (but I could not enumerate what kinds of cruft you should be looking for).



  • Running pkg-config from the command line:

    % /usr/bin/pkg-config --libs xkbcommon
    -lxkbcommon
    

    And "apt-cache show libxkbcommon-dev" shows version 0.8.0-1.
    Thanks for all your help @KH-219Design !
    I've been evaluating Qt for a seafloor-mapping project for a few months now - Qt has its share of bugs, there are many many moving pieces to it, many of those pieces barely documented or not documented at all - a very steep learning curve, at least for me. I'm grateful that you and others in the community provide invaluable help!


  • Lifetime Qt Champion

    What Ubuntu version are you running ?



  • @Tom-asso said in Definitive guide to building source from downloaded .run file?:

    xkbcommon.h not found in [] and global paths

    I'm reading through this right now... seems like the same "xkbcommon" problem: https://forum.qt.io/topic/100908/qt-5-12-2-raspberry-pi-x11/16



  • @KH-219Design said in Definitive guide to building source from downloaded .run file?:

    seems like the same "xkbcommon" problem: https://forum.qt.io/topic/100908/qt-5-12-2-raspberry-pi-x11/16

    Maybe I spoke too soon. Although the same error is mentioned, that thread seems entirely RPi specific in the end. Arggg...



  • I also found this: https://github.com/RudolfCardinal/camcops/issues/3

    ... which seems to circle back to:

    sudo sed -i -- 's/#deb-src/deb-src/g' /etc/apt/sources.list
    sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
    sudo apt-get update
    
    sudo apt-get build-dep qt5-default
    

    Has that been tried yet? I've lost track :)



  • @SGaist - I am running Ubuntu 18.04.4



  • Thanks @KH-219Design - I haven't tried the "sed" yet - what exactly will those commands do?

    sudo sed -i -- 's/#deb-src/deb-src/g' /etc/apt/sources.list
    sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
    sudo apt-get update
    
    sudo apt-get build-dep qt5-default
    


  • @Tom-asso said in Definitive guide to building source from downloaded .run file?:

    I haven't tried the "sed" yet - what exactly will those commands do?

    The sed commands are to work around:

    E: You must put some 'source' URIs in your sources.list
    

    Described here: https://wiki.qt.io/Building_Qt_5_from_Git#Linux.2FX11



  • I'm reluctant to install the ubuntu qt5-default at this point - in the past I've run into problems when mixing ubuntu qt-related packages with source/software downloaded from download.qt.io. And I don't think I've actually seen the message "E: You must put some 'source' URIs in your sources.list".



  • Ah. I totally understand your concern about mixing and matching the "Ubuntu system Qt5" with the one that you built.

    But not to fear! The command suggested by me (and several wiki pages, and on that github issue I linked to this morning) is not for installing the Qt5 system binary libraries!

    The command is to install BUILD dependencies:

    sudo apt-get build-dep qt5-default
    

    Note the: build-dep

    https://askubuntu.com/questions/324845/whats-the-difference-between-apt-get-install-and-apt-get-build-dep



  • Wow. An eerily similar discussion is going on simultaneously: https://forum.qt.io/topic/114826/static-build-qt-getting-error-because-of-xcb/6

    Maybe there is something broken with configure of 5.14.2.

    The last time I successfully built from source was 5.14.0, so I wonder...

    (If I have time later today or tomorrow, perhaps I will try with 14.2)



  • This post is deleted!


  • Hmm... I'm stuck in a place with really slow bandwidth, but I'll try to get qt-everywhere-src-5.14.0.tar.xz and build.
    @KH-219Design - did you build 5.14.0 on ubuntu? What version, and how did it go?



  • @Tom-asso said in Definitive guide to building source from downloaded .run file?:

    did you build 5.14.0 on ubuntu? What version, and how did it go?

    I built in on both Ubuntu 18.04 and 16.04 and it went perfectly well. But I cloned the sources from code.qt.io and used the script I linked to earlier: https://github.com/219-design/build_qt_binaries/blob/09ad9369c8abfead615075f067f402fd89f/script.sh



  • @KH-219Design said in Definitive guide to building source from downloaded .run file?:

    sudo sed -i -- 's/#deb-src/deb-src/g' /etc/apt/sources.list
    sudo sed -i -- 's/# deb-src/deb-src/g' /etc/apt/sources.list
    sudo apt-get update

    sudo apt-get build-dep qt5-default

    I ran those commands. apt-get build-dep qt5-default said:

    The following NEW packages will be installed:
      debhelper dh-autoreconf dh-strip-nondeterminism freetds-common freetds-dev
      gir1.2-gtk-2.0 libasound2-dev libatk1.0-dev libatspi2.0-dev
      libcairo-script-interpreter2 libcairo2-dev libct4 libcups2-dev
      libcupsimage2-dev libevdev-dev libfile-stripnondeterminism-perl libgbm-dev
      libgdk-pixbuf2.0-dev libgstreamer-plugins-base1.0-dev libgstreamer1.0-dev
      libgtk2.0-dev libinput-dev libmtdev-dev liborc-0.4-dev liborc-0.4-dev-bin
      libpango1.0-dev libpixman-1-dev libproxy-dev libpulse-dev libsybdb5
      libudev-dev libwacom-dev libxcb-icccm4-dev libxcb-image0-dev
      libxcb-keysyms1-dev libxcb-render-util0-dev libxcb-shm0-dev libxcb-xkb-dev
      libxcomposite-dev libxcursor-dev libxi-dev libxinerama-dev
      libxkbcommon-x11-dev libxml2-utils libxtst-dev pkg-kde-tools po-debconf
      x11proto-composite-dev x11proto-record-dev x11proto-xinerama-dev xvfb
    

    So it wants to install libxkbcommon-11-dev, among other things. I let it run, then again tried to configure the build:

    ./configure -qt-xcb
    [...]
    ERROR: Feature 'xcb' was enabled, but the pre-condition 'features.thread && features.xkbcommon && libs.xcb' failed.
    

    And config.log still contains this:

    loaded result for library config.qtbase_gui.libraries.xkbcommon
    Trying source 0 (type pkgConfig) of library xkbcommon ...
    + /usr/bin/pkg-config --exists --silence-errors xkbcommon '>=' 0.5.0
    pkg-config did not find package.
    


  • I downloaded and extracted qt-everywhere-src-5.14.0.tar.xz, ran './configure -qt-xcb' without error, built and installed it. My qtdatavisualization3d app links successfully and runs. Likewise with qt-everywhere-src-5.14.1.tar.xz. HOWEVER my app runs extremely and unacceptably slowly with 5.14.0 and 5.14.1, so this does NOT solve my problem. But this result indicates there's a problem in configuration scripts for 5.14.2. @SGaist , how do we make this problem known to the Qt team?


  • Lifetime Qt Champion

    Check the bug report system.



  • Many thanks to all for your help in solving this problem for me!

    The following procedure to build Qt from the "offline installer" .run file,
    e.g. qt-opensource-linux-x64-5.14.2.run, works for me on ubuntu 18.04.4:

    1. Download .run file from "official release" site
    2. Execute the .run file downloaded in the previous step and answer questions prompted by the "wizard"
    3. Do the following:
    % cd <QtHome>/5.14.2/Src
    % ./configure -qt-xcb   # I want to build Qt's xcb sources
    % make
    % make install  # Installs into /usr/local/Qt5.14.2 by default
    

    To build Qt applications using those sources and libraries do the following:

    % export PATH=/usr/local/Qt5.14.2/bin:$PATH
    % export LD_LIBRARY_PATH=/usr/local/Qt5.14.2/lib:$LD_LIBRARY_PATH
    

    Setting PATH like this ensures that the qmake executable is properly associated with the headers and libraries you installed in /usr/local/Qt5.14.2.


Log in to reply