Cannot find -lQt5Multimedia



  • Hello,

    I'm trying to get the Qt examples related to multimedia/video working.

    • Ubuntu 14.04
    • Qt Creator 3.4.1 and Qt 5.4.2 (GCC 4.6.1, 64 bit)

    I copied the examples from the installation path:
    cp -r /opt/Qt5.4.2/Examples/Qt-5.4/multimediawidgets/ ~/qt_examples

    I try to compile the videowidget example, I did not modify a single line in the project, here is the error:

    /usr/bin/ld: cannot find -lQt5Multimedia
    collect2: error: ld returned 1 exit status
    make: *** [videowidget] Error 1
    18:17:01: Le processus "/usr/bin/make" s'est terminé avec le code 2.
    Erreur lors de la compilation/déploiement du projet videowidget (kit : Desktop)
    When executing step "Make"
    

    Here are the libraries that I have:

    $ dpkg  -L libqt5multimedia5
    /.
    /usr
    /usr/lib
    /usr/lib/x86_64-linux-gnu
    /usr/lib/x86_64-linux-gnu/libQt5Multimedia.so.5.2.1
    diverted by libqt5multimedia5-touch to: /var/lib/libqt5multimedia5-touch-diverted/libQt5Multimedia.so.5.2.1.diverted-libqt5multimedia5-touch
    /usr/share
    /usr/share/doc
    /usr/share/doc/libqt5multimedia5
    /usr/share/doc/libqt5multimedia5/changelog.Debian.gz
    /usr/share/doc/libqt5multimedia5/copyright
    /usr/lib/x86_64-linux-gnu/libQt5Multimedia.so.5.2
    diverted by libqt5multimedia5-touch to: /var/lib/libqt5multimedia5-touch-diverted/libQt5Multimedia.so.5.2.diverted-libqt5multimedia5-touch
    /usr/lib/x86_64-linux-gnu/libQt5Multimedia.so.5
    diverted by libqt5multimedia5-touch to: /var/lib/libqt5multimedia5-touch-diverted/libQt5Multimedia.so.5.diverted-libqt5multimedia5-touch
    

    I tried to add INCLUDEPATH += /usr/lib/x86_64-linux-gnu/ in the .pro file, it doesn't change anything.
    How do I install Qt with multimedia support, or how do I get this example working?

    Bye



  • Looks like it's trying to use your system's version of Qt instead of the one you have in /opt/Qt5.4.2. Is Qt 5.4.2 listed in QtCreator in Tools->Options->Build & Run? If not, add it and use the Build kit that uses this Qt version.



  • Hi.
    INCLUDEPATH need for your .h files.
    You can try add to your .pro file path to Qt libs:
    LIBS += -L /path_to_qt_libs/ -l lib_filename.so

    --
    Peace



  • Thanks for your answers; the problem was indeed the default configuration, my mistake was trusting the information in the "About panel" of Qt Creator; you also have to make sure you have chosen Qt 5.4.2 as the default configuration, just like on the image below: (Tools > Options > Build & Run > Kits > Make the right one the default)
    Qt 5.4.2 configuration

    Now the compilation runs fine and the program launches.