[Solved] QApplication: No such file or directory

  • I got Qt5 installed on Opensuse 12.2.
    I tried to compile some example project that compiled successfully on Qt 4.8.
    Now I get error message "QApplication: No such file or directory"
    I think the PATH to library is missing while I installed locally on /home/

    Where should I edit?

  • Moderators

    How do you include QApplication header? In Qt5, it resides in <QtWidgets/QApplication>, while in Qt4 it was <QtGui/QApplication>.

  • I think the module isn't added in .pro file, so did you added QT += widgets in your .pro file?

    //anyway if the module is added the header can be included with #include <QApplication> you don't need <QtWidgets/QApplication> or <QtGui/QApplication> in Qt4 (that works with both Qt4 and 5)

  • Adding QT += widgets in .pro file made the trick. Thanks.

  • Why does qmake not include these, or what must one do in the source to ensure qmake auto generates this line in the .pro file ?

  • Moderators

    qmake will never generate anything in your .pro file. Those files are config files for qmake to use, not the other way around. If you create a new project in recent versions of Qt Creator, this line will be added for you in standard app template.

  • Ooh ok, that make more sense now, thanks for the reply.

    Sorry for hijacking the thread by the way :D

  • The "Adding QT += widgets in .pro file" really helped me as well. Thanks.

  • I'm happy, too. I solved.

    Why qmake --project is doing a so simple task in a wrong way?

  • can qmake -project add "QT += widgets" to .pro automatically ?

  • Just to say what happened to be my problem, it was a dumb error:

    I was following a guide that had me open an empty QT project, which gave me a .pro file but left it empty. I had filled in some data and "TEMPLATE = application" as they has mentioned it. I already had the "widgets" line but it still couldn't find the library as I included it in the .cpp file. When I changed it to "TEMPALTE = app" the .pro file was parsed, and the file to include resolved correctly (QApplication).

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