CODEWITHSUNDEEP
c++qt
AmeNawa
AmeNawa

Reputation: 21

QT 5.5 setLayout() by return value

I'm trying to set widget's layout by setLayout by function and i recive error messages:

main.obj:-1: error: LNK2019: unresolved external symbol "public: __cdecl LayoutManager::LayoutManager(void)" (??0LayoutManager@@QEAA@XZ) referenced in function main

main.obj:-1: error: LNK2019: unresolved external symbol "public: class QVBoxLayout * __cdecl LayoutManager::setHelloLayout(void)" (?setHelloLayout@LayoutManager@@QEAAPEAVQVBoxLayout@@XZ) referenced in function main

main.cpp

int main(int argc, char *argv[]){
    QApplication app(argc, argv);
    MainWindow mWin; //main widget
    LayoutManager *LayMan = new LayoutManager();
    mWin.setLayout(LayMan->setHelloLayout());

    mWin.show();

    return app.exec();
}

layoutmanager.h

class LayoutManager : public MainWindow
{
    Q_OBJECT

    void (*set_Lo_Pt[LAST_LAYOUT])(MainWindow&);

public:
    LayoutManager();
    ~LayoutManager();

    QVBoxLayout* setHelloLayout();  

};

And here is setHelloLayout() function

QVBoxLayout* LayoutManager::setHelloLayout(){


    QVBoxLayout *menuOptions = new QVBoxLayout();

    QPushButton *but_HouseManager = new QPushButton("HouseManager");
    QPushButton *but_Help = new QPushButton("Help");
    QPushButton *but_Quit = new QPushButton("Quit");


    menuOptions->addWidget(but_HouseManager);
    menuOptions->addWidget(but_Help);
    menuOptions->addWidget(but_Quit);

    return menuOptions;

}

Class MainWindow is derived from QWidget

Is it problem with function body or I should change whole layout changing system?

Here is Compile Output

21:18:33: Running steps for project HM...
21:18:33: Configuration unchanged, skipping qmake step.
21:18:33: Starting: "D:\Qt\Tools\QtCreator\bin\jom.exe" 
    D:\Qt\Tools\QtCreator\bin\jom.exe -f Makefile.Debug
    link /NOLOGO /DYNAMICBASE /NXCOMPAT /DEBUG /SUBSYSTEM:WINDOWS "/MANIFESTDEPENDENCY:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' publicKeyToken='6595b64144ccf1df' language='*' processorArchitecture='*'" /MANIFEST:embed /OUT:debug\HM.exe @C:\Users\MICHA~1\AppData\Local\Temp\HM.exe.4644.15.jom
main.obj : error LNK2019: unresolved external symbol "public: __cdecl LayoutManager::LayoutManager(void)" (??0LayoutManager@@QEAA@XZ) referenced in function main
main.obj : error LNK2019: unresolved external symbol "public: class QVBoxLayout * __cdecl LayoutManager::setHelloLayout(void)" (?setHelloLayout@LayoutManager@@QEAAPEAVQVBoxLayout@@XZ) referenced in function main
debug\HM.exe : fatal error LNK1120: 2 unresolved externals
jom: D:\Qt\build-HM-Desktop_Qt_5_5_1_MSVC2013_64bit-Debug\Makefile.Debug [debug\HM.exe] Error 1120
jom: D:\Qt\build-HM-Desktop_Qt_5_5_1_MSVC2013_64bit-Debug\Makefile [debug] Error 2
21:18:33: The process "D:\Qt\Tools\QtCreator\bin\jom.exe" exited with code 2.
Error while building/deploying project HM (kit: Desktop Qt 5.5.1 MSVC2013 64bit)
When executing step "Make"
21:18:33: Elapsed time: 00:00.

This is .pro file

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = HM
TEMPLATE = app


SOURCES += main.cpp\
        mainwindow.cpp \
    layoutmanager.cpp

HEADERS  += mainwindow.h \
    layoutmanager.h

Upvotes: 1

Views: 130

Answers (3)

Fox
Fox

Reputation: 2138

a. Please check the file-name for the cpp file containing the setHelloLayout() and the ctor - and compare it with what is in the .pro file. Both linker errors are with the same class's functions (and all needed functions fail linkage) - this means the CU for the class definition isn't being picked up.

b. With newly added/renamed files, qmake sometimes fails to pick up dependencies (and worse, refuses to remove old intermediates and links to them) - (i.e. the decision to "Configuration Unchanged - skipping qmake step" may be wrong). If you've recently renamed the file / class, please make a clean build (remove mocs & object files) and run qmake again.

Upvotes: 0

AmeNawa
AmeNawa

Reputation: 21

I've added a few modules to .pro file like multimedia, quick, widgets then builded it and it works. I don't know how does it work because after that I removed one after one and when I builded without these modules again it's still working. It seems like a bug for me (I'm doing everything in QTCreator) or I just don't understand how exactly compilator works.

Upvotes: 1

Craig Scott
Craig Scott

Reputation: 10137

Looks more like a problem with your link command. Can you update your question with your build tool's output for the link command? It would seem that you are missing the object file for the .cpp file that provides the implementation of your LayoutManager class.

Upvotes: 0

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