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  4. Basic question: Including headers with INCLUDEPATH doesn't work
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Basic question: Including headers with INCLUDEPATH doesn't work

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  • B Binary91

    I really don't know from where this "myudp.cpp" comes. Maybe a de-zipping error. That should mean "lib/sources/myQLineEdit.cpp"

    Yeah this way its getting built on my computer as well, but there you manually added the header file to the project:
    INCLUDES += ...
    or
    HEADERS +=...

    That is what I try to avoid by using INCLUDEPATH. That was what the discussion is all about...

    jsulmJ Offline
    jsulmJ Offline
    jsulm
    Lifetime Qt Champion
    wrote on last edited by
    #41

    @Binary91 Where did I add the header file manually?
    I commented out the old line, please take a look again:

    QT       += core network
    
    QT       -= gui
    
    TARGET = test
    CONFIG   += console
    CONFIG   -= app_bundle
    
    TEMPLATE = app
    
    #INCLUDES += lib/headers/myQLineEdit.h <-- this line is commented out
    INCLUDEPATH += lib/headers
    
    SOURCES += main.cpp
    

    https://forum.qt.io/topic/113070/qt-code-of-conduct

    1 Reply Last reply
    0
    • B Offline
      B Offline
      Binary91
      wrote on last edited by
      #42

      but where is the myQLineEdit.cpp ?
      You just added the main.cpp. The error occures in myQLineEdit.cpp, because it holds methods of myQLineEdit class in myQLineEdit.h that has a Q_OBJECT within...

      jsulmJ 1 Reply Last reply
      0
      • B Binary91

        but where is the myQLineEdit.cpp ?
        You just added the main.cpp. The error occures in myQLineEdit.cpp, because it holds methods of myQLineEdit class in myQLineEdit.h that has a Q_OBJECT within...

        jsulmJ Offline
        jsulmJ Offline
        jsulm
        Lifetime Qt Champion
        wrote on last edited by
        #43

        @Binary91 Your project is really broken:

        QT       += core network
        
        QT       += gui widgets
        
        TARGET = test
        CONFIG   += console
        CONFIG   -= app_bundle
        
        TEMPLATE = app
        
        HEADERS += lib/headers/myQLineEdit.h
        INCLUDEPATH += lib/headers
        
        SOURCES += main.cpp \
            lib/sources/myQLineEdit.cpp
        

        myQLineEdit.cpp

        #include <myQLineEdit.h> // absolute path or absolute path with whitespaces also doesn't work
        
        
        // ----- constructors -----
        
        myQLineEdit::myQLineEdit(QWidget* widgetParent) : QLineEdit(widgetParent)
        {
           // stuff
        }
        
        myQLineEdit::~myQLineEdit()
        {
        
        }
        
        #include "../build-test-Desktop-Debug/moc_myQLineEdit.cpp"
        

        Without HEADERS moc_ file is not generated and the header file is not shown in QtCreator, so you should use HEADERS.

        https://forum.qt.io/topic/113070/qt-code-of-conduct

        jsulmJ 1 Reply Last reply
        0
        • jsulmJ jsulm

          @Binary91 Your project is really broken:

          QT       += core network
          
          QT       += gui widgets
          
          TARGET = test
          CONFIG   += console
          CONFIG   -= app_bundle
          
          TEMPLATE = app
          
          HEADERS += lib/headers/myQLineEdit.h
          INCLUDEPATH += lib/headers
          
          SOURCES += main.cpp \
              lib/sources/myQLineEdit.cpp
          

          myQLineEdit.cpp

          #include <myQLineEdit.h> // absolute path or absolute path with whitespaces also doesn't work
          
          
          // ----- constructors -----
          
          myQLineEdit::myQLineEdit(QWidget* widgetParent) : QLineEdit(widgetParent)
          {
             // stuff
          }
          
          myQLineEdit::~myQLineEdit()
          {
          
          }
          
          #include "../build-test-Desktop-Debug/moc_myQLineEdit.cpp"
          

          Without HEADERS moc_ file is not generated and the header file is not shown in QtCreator, so you should use HEADERS.

          jsulmJ Offline
          jsulmJ Offline
          jsulm
          Lifetime Qt Champion
          wrote on last edited by
          #44

          @jsulm said in Basic question: Including headers with INCLUDEPATH doesn't work:

          #include "../build-test-Desktop-Debug/moc_myQLineEdit.cpp"

          you can change it to:

          #include "moc_myQLineEdit.cpp"
          

          It builds now on my machine.

          https://forum.qt.io/topic/113070/qt-code-of-conduct

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          • BuckwheatB Buckwheat

            @jsulm , why would you include the MOC files? I "never" include the MOC files in my source because they get generated, compiled, and linked after the normal build. The only generated file I would include is the ui_NameOfForm.h file created when using the form designer. And, only in the CPP for the UI class.

            @Binary91 , I am sure it was explained that INCLUDEPATH tells qmake where to find common include files. I use it for 3rd party libraries or pre-built packages I developed for Qt (I treat them like 3rd party libraries). And, as I know you know... always run qmake after changing a PRO file.

            There is one curious item I have found about QtCreator though... if you are using static libraries (even if your dependencies are setup) and make a change to a CPP file in the library... Press build-all and it will build the library and NOT re-link the application or shared library that depends on that static library. Kind of annoying but I just get around it!

            jsulmJ Offline
            jsulmJ Offline
            jsulm
            Lifetime Qt Champion
            wrote on last edited by
            #45

            @Buckwheat You need to include moc_ files for your own classes which are derived from QObject (directly or indirectly).

            https://forum.qt.io/topic/113070/qt-code-of-conduct

            BuckwheatB 1 Reply Last reply
            0
            • B Offline
              B Offline
              Binary91
              wrote on last edited by
              #46

              Hi jsulm,

              so you say, I need to include the headers with HEADERS in the project file. Well, then I'm asking myself what the INCLUDEPATH command is for?

              mrjjM 1 Reply Last reply
              0
              • B Binary91

                Hi jsulm,

                so you say, I need to include the headers with HEADERS in the project file. Well, then I'm asking myself what the INCLUDEPATH command is for?

                mrjjM Offline
                mrjjM Offline
                mrjj
                Lifetime Qt Champion
                wrote on last edited by mrjj
                #47

                @Binary91 said in Basic question: Including headers with INCLUDEPATH doesn't work:

                INCLUDEPATH
                http://doc.qt.io/qt-5/qmake-variable-reference.html#includepath

                Its used to specify where to look for headers.
                So when it sees #include "YYYY" it will search for them there.

                as shown with

                INCLUDEPATH += ../../Common/CONET
                ../../Common/XML/pugixml-1.5/src/ \

                the pugixml.h is in the src and i can just use
                it like
                #include "pugixml.h"

                Without it I would have to do use full path to it.

                That is its role and it works fine here.

                You seem to expect that point to a folder with INCLUDEPATH,
                implies that all should be used ?

                Like all where already added to HEADERS ?

                There is one issue if it did that.
                For all HEADERS , it need to run moc on them so
                if you use INCLUDEPATH to point to a place with many .H files
                you be wasting tons of time running moc on those completely unrelated files.
                Hence HEADERS tells us what files to run moc on.
                Of course this could be fixed checking against which are actually seen via #include
                but it's not the way it works currently. :)

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                2
                • B Offline
                  B Offline
                  Binary91
                  wrote on last edited by
                  #48

                  thank you mrjj, that was the explanation I was looking for!

                  I didn't know that with HEADERS I tell the compiler which moc files should be generated!

                  So all in all, I have to include those headers to my project and everything is going well.

                  Thank you for your help.

                  Kind regards,
                  Binary

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                  1
                  • jsulmJ jsulm

                    @Buckwheat You need to include moc_ files for your own classes which are derived from QObject (directly or indirectly).

                    BuckwheatB Offline
                    BuckwheatB Offline
                    Buckwheat
                    wrote on last edited by
                    #49

                    @jsulm Actually you don't. When the build system sees the Q_OBJECT, it will build and compile a MOC file for you. It will link into the application and be part of it. No inclusion is necessary. None at all. The only think you would ever include is a form generated header file (ie. ui_MainWindow.h) that will hold the form variables for you.

                    If doubting, watch your build on any system. You will see the CPP files compile and then the moc_*.cpp files compile and then the linker will have both on it. The MOC files tie your class to the signal/slots and meta object data all under the scenes. It is quite beautifully designed.

                    Dave Fileccia

                    1 Reply Last reply
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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #50

                      If your QObject based class is in a .cpp file then you need to include the moc file at the bottom. See the unit tests form Qt for example.

                      Interested in AI ? www.idiap.ch
                      Please read the Qt Code of Conduct - https://forum.qt.io/topic/113070/qt-code-of-conduct

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