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Save object to a file

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  • D Offline
    D Offline
    Dmon
    wrote on last edited by
    #11

    if I take out #include "Film.h" in FilmWriter there is a problem with the FilmWriter class, if I then take out : public Film there is a problem with the func saveFilm because it's parameter is of type Film. So how do I make it know how to use Film?

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    • SGaistS Offline
      SGaistS Offline
      SGaist
      Lifetime Qt Champion
      wrote on last edited by
      #12

      This is C/C++ basic knowledge. Without the header file how would your class know anything about Film ?

      What problem would it be ?

      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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      • D Offline
        D Offline
        Dmon
        wrote on last edited by
        #13

        well it wouldn't know about Film without the header file. Are you saying that it doesn't need to be a child of Film but just include the header?

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        • SGaistS Offline
          SGaistS Offline
          SGaist
          Lifetime Qt Champion
          wrote on last edited by
          #14

          Yes, it's exactly what I'm saying

          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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          • D Offline
            D Offline
            Dmon
            wrote on last edited by
            #15

            Ok great. But now after the changes I am still getting the same error :-?
            :: error: collect2: ld returned 1 exit status

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            • SGaistS Offline
              SGaistS Offline
              SGaist
              Lifetime Qt Champion
              wrote on last edited by
              #16

              If you are talking about the saveFilm problem and the message didn't changed, then saveFilm is still not a member of FilmInput.

              Isn't it a member of FilmWriter ?

              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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              • D Offline
                D Offline
                Dmon
                wrote on last edited by
                #17

                Yes and I don't want it to be a member of FilmInput, I want it to be member of FilmWriter only and somehow (I don't know how) be called in FilmInput. I thought if I included the FilmWriter header it would work, but obviously I must do something else.

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                • SGaistS Offline
                  SGaistS Offline
                  SGaist
                  Lifetime Qt Champion
                  wrote on last edited by
                  #18

                  FilmWriter is a class, how do you call a function from a class ?

                  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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                  • D Offline
                    D Offline
                    Dmon
                    wrote on last edited by
                    #19

                    You create an object and call the function with the object. That's it! Ok so now you have helped me to get rid of that error, thanks a lot. Another question, when I click on the save film button which invokes saveFilm the program crashes, should I start a new thread because this is a new question or can you still help me on this one?

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                    • SGaistS Offline
                      SGaistS Offline
                      SGaist
                      Lifetime Qt Champion
                      wrote on last edited by
                      #20

                      Run your application through the debugger, it will tell you where the crash occurs

                      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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                      • D Offline
                        D Offline
                        Dmon
                        wrote on last edited by
                        #21

                        I got this: The inferior stopped because it received a signal from the operating system
                        signal name: SIGSEGV
                        Signal meaning: Segmentation fault
                        then it is pointing to line 2185 in qglobal.h
                        inline QFlags operator&(Enum f) const { QFlags g; g.i = i & f; return g; }

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                        • SGaistS Offline
                          SGaistS Offline
                          SGaist
                          Lifetime Qt Champion
                          wrote on last edited by
                          #22

                          What does the stack trace look like ?
                          The lines under qglobal.h ?

                          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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                          • D Offline
                            D Offline
                            Dmon
                            wrote on last edited by
                            #23

                            I have a print screen, how do I post a pic on here?

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                            • SGaistS Offline
                              SGaistS Offline
                              SGaist
                              Lifetime Qt Champion
                              wrote on last edited by
                              #24

                              You have to use a picture hosting service or a public dropbox folder etc...

                              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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                              • D Offline
                                D Offline
                                Dmon
                                wrote on last edited by
                                #25

                                https://www.dropbox.com/s/oal5r9sjtsmy42l/Qt stack.jpg

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                                • D Offline
                                  D Offline
                                  Dmon
                                  wrote on last edited by
                                  #26

                                  https://www.dropbox.com/s/mosnz8o23elipn5/Qtstack.jpg

                                  doesn't work with a space in the name

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                                  • SGaistS Offline
                                    SGaistS Offline
                                    SGaist
                                    Lifetime Qt Champion
                                    wrote on last edited by
                                    #27

                                    Looks strange... Just to be on the safe side, delete the build directory completely and re-run your application.

                                    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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                                    • D Offline
                                      D Offline
                                      Dmon
                                      wrote on last edited by
                                      #28

                                      ok now it doesn't run again with a bunch of errors:

                                      Running build steps for project Ass1Q1...
                                      Configuration unchanged, skipping qmake step.
                                      Starting: "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" -w
                                      mingw32-make: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop' C:/Qt/2010.04/mingw/bin/mingw32-make -f Makefile.Debug mingw32-make[1]: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                                      g++ -c -g -frtti -fexceptions -mthreads -Wall -DUNICODE -DQT_LARGEFILE_SUPPORT -DQT_DLL -DQT_GUI_LIB -DQT_CORE_LIB -DQT_THREAD_SUPPORT -DQT_NEEDS_QMAIN -I"........\Qt\2010.04\qt\include\QtCore" -I"........\Qt\2010.04\qt\include\QtGui" -I"........\Qt\2010.04\qt\include" -I"........\Qt\2010.04\qt\include\ActiveQt" -I"debug" -I"." -I"..\Ass1Q1" -I"." -I"........\Qt\2010.04\qt\mkspecs\win32-g++" -o debug\FilmWriter.o ..\Ass1Q1\FilmWriter.cpp
                                      ..\Ass1Q1\FilmWriter.cpp: In member function 'void FilmWriter::saveFilm(Film&)':
                                      ..\Ass1Q1\FilmWriter.cpp:10: error: no matching function for call to 'QFileDialog::getSaveFileName(FilmWriter* const, const char [10])'
                                      ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qfiledialog.h:216: note: candidates are: static QString QFileDialog::getSaveFileName(QWidget*, const QString&, const QString&, const QString&, QString*, QFlagsQFileDialog::Option)
                                      ..\Ass1Q1\FilmWriter.cpp:14: error: no matching function for call to 'QMessageBox::critical(FilmWriter* const, const char [6], const char [20])'
                                      ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:202: note: candidates are: static QMessageBox::StandardButton QMessageBox::critical(QWidget*, const QString&, const QString&, QFlagsQMessageBox::StandardButton, QMessageBox::StandardButton)
                                      ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:262: note: static int QMessageBox::critical(QWidget*, const QString&, const QString&, int, int, int)
                                      ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:265: note: static int QMessageBox::critical(QWidget*, const QString&, const QString&, const QString&, const QString&, const QString&, int, int)
                                      ........\Qt\2010.04\qt\include\QtGui/../../src/gui/dialogs/qmessagebox.h:272: note: static int QMessageBox::critical(QWidget*, const QString&, const QString&, QMessageBox::StandardButton, QMessageBox::StandardButton)
                                      mingw32-make[1]: Leaving directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop' mingw32-make: Leaving directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                                      mingw32-make[1]: *** [debug/FilmWriter.o] Error 1
                                      mingw32-make: *** [debug] Error 2
                                      The process "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" exited with code %2.
                                      Error while building project Ass1Q1 (target: Desktop)
                                      When executing build step 'Make'

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                                      • SGaistS Offline
                                        SGaistS Offline
                                        SGaist
                                        Lifetime Qt Champion
                                        wrote on last edited by
                                        #29

                                        FilmWriter is not a QWidget, you can't pass it as a parent when you call QFileDialog::getSaveFileName

                                        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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                                        • D Offline
                                          D Offline
                                          Dmon
                                          wrote on last edited by
                                          #30

                                          If I make FilmWriter a QWidget the program runs but when I click on the save film button it crashes with: "this application has requested the runtime to terminate it in an unusual way. Please contact the application's support team for more information."

                                          Despite the crash, the program runs without any errors as you can see:
                                          Running build steps for project Ass1Q1...
                                          Configuration unchanged, skipping qmake step.
                                          Starting: "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" -w
                                          mingw32-make: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop' C:/Qt/2010.04/mingw/bin/mingw32-make -f Makefile.Debug mingw32-make[1]: Entering directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                                          mingw32-make[1]: Nothing to be done for first'. mingw32-make[1]: Leaving directory C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                                          mingw32-make: Leaving directory `C:/Unisa/COS3711/assignments/Ass1Q1-build-desktop'
                                          The process "C:/Qt/2010.04/mingw/bin/mingw32-make.exe" exited normally.

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