Error: symbol(s) not found for architecture x86_64, collect2: ld returned 1 exit status

Question

I have been struggling for a while with an issue on Qt.

Here is my code:

hexbutton.h:

#ifndef HEXBUTTON_H
#define HEXBUTTON_H

#include <QPushButton>
#include <QWidget>
#include <QIcon>

class HexButton : public QPushButton
{
    Q_OBJECT

public:
    HexButton(QWidget *parent, QIcon &icon, int i, int j);

public slots:
    void changeIcon();
};

#endif // HEXBUTTON_H

Hexbutton.cpp:

#include "hexbutton.h"

HexButton::HexButton(QWidget *parent, QIcon &icon, int i , int j) : QPushButton(parent){
    //setFlat(true);
    setIcon(icon);
    setGeometry((i*40)+((j*40)/2), j*40, 40, 40);
}

void HexButton::changeIcon(){
        setIcon(QIcon("/Users/jonathanbibas/Documents/Workspace Qt/Test/hexagon.gif"));
}

MyWindow.h:

#ifndef MYWINDOW_H
#define MYWINDOW_H

#include <QApplication>
#include <QWidget>
#include <QPushButton>
#include <QLCDNumber>
#include <QSlider>
#include <QProgressBar>
#include "hexbutton.h"



class MyWindow : public QWidget
{

public:
    MyWindow();
    ~MyWindow();

private:
    HexButton * myButtons[11][11];
};



#endif // MYWINDOW_H

MyWindow.cpp:

#include "MyWindow.h"
#include <QColor>
#include <QIcon>


MyWindow::MyWindow() : QWidget() {


    setFixedSize(740, 440);

    QIcon icon = QIcon("/Users/jonathanbibas/Documents/Workspace Qt/Test/whitehexagon.png");

    for(int i =0 ; i < 11 ; i ++){
        for(int j =0 ; j < 11 ; j ++){


            myButtons[i][j] = new HexButton(this, icon, i, j);

            QObject::connect(myButtons[i][j], SIGNAL(clicked()), myButtons[i][j], SLOT(changeIcon()));
        }
    }
}



MyWindow::~MyWindow()
{
    delete myButtons;

}

And finally, Main.cpp:

#include <QApplication>
#include "MyWindow.h"


int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

        MyWindow fenetre;
        fenetre.show();

        return app.exec();
}

Just in case, here is the Test.pro

SOURCES += \
    Main.cpp \
    MyWindow.cpp \
    hexbutton.cpp

HEADERS += \
    MyWindow.h \
    hexbutton.h

And I get the 2 errors:

1) symbol(s) not found for architecture x86_64

2) collect2: ld returned 1 exit status

It also says 121 times (11*11):

Object::connect: No such slot QPushButton::changeIcon() in ../Test/MyWindow.cpp:19

and on the compile output it says:

18:22:15: Running build steps for project Test...
18:22:15: Configuration unchanged, skipping qmake step.
18:22:15: Starting: "/usr/bin/make" -w
make: Entering directory `/Users/jonathanbibas/Documents/Workspace Qt/Test-build-desktop-Desktop_Qt_4_8_0_for_GCC__Qt_SDK__Debug'
g++ -c -pipe -g -gdwarf-2 -arch x86_64 -Xarch_x86_64 -mmacosx-version-min=10.5 -Wall -W -DQT_GUI_LIB -DQT_CORE_LIB -I../../../QtSDK/Desktop/Qt/4.8.0/gcc/mkspecs/macx-g++ -I../Test -I../../../QtSDK/Desktop/Qt/4.8.0/gcc/lib/QtCore.framework/Versions/4/Headers -I../../../QtSDK/Desktop/Qt/4.8.0/gcc/include/QtCore -I../../../QtSDK/Desktop/Qt/4.8.0/gcc/lib/QtGui.framework/Versions/4/Headers -I../../../QtSDK/Desktop/Qt/4.8.0/gcc/include/QtGui -I../../../QtSDK/Desktop/Qt/4.8.0/gcc/include -I. -I../Test -I. -F/Users/jonathanbibas/QtSDK/Desktop/Qt/4.8.0/gcc/lib -o hexbutton.o ../Test/hexbutton.cpp
g++ -headerpad_max_install_names -arch x86_64 -Xarch_x86_64 -mmacosx-version-min=10.5 -o Test.app/Contents/MacOS/Test Main.o MyWindow.o hexbutton.o moc_MyWindow.o   -F/Users/jonathanbibas/QtSDK/Desktop/Qt/4.8.0/gcc/lib -L/Users/jonathanbibas/QtSDK/Desktop/Qt/4.8.0/gcc/lib -framework QtGui -framework QtCore 
Undefined symbols for architecture x86_64:
  "vtable for HexButton", referenced from:
      HexButton::HexButton(QWidget*, QIcon&, int, int)in hexbutton.o
      HexButton::HexButton(QWidget*, QIcon&, int, int)in hexbutton.o
  NOTE: a missing vtable usually means the first non-inline virtual member function has no definition.
ld: symbol(s) not found for architecture x86_64
collect2: ld returned 1 exit status
make: *** [Test.app/Contents/MacOS/Test] Error 1
make: Leaving directory `/Users/jonathanbibas/Documents/Workspace Qt/Test-build-desktop-Desktop_Qt_4_8_0_for_GCC__Qt_SDK__Debug'
18:22:20: The process "/usr/bin/make" exited with code 2.
Error while building project Test (target: Desktop)
When executing build step 'Make'

Apparently the error comes from the Q_OBJECT (needed for the slots definition), but there is something wrong with my code, not with my compiler (because I have when slots are in MainWindow, it works fine).

Thank you for your help!

Answer 1

Faced same problem

1. undefined refrence error for my signal.
2. After putting Q_OBJECT macro... vtable errors.

I did this and worked for me

• Added Q_OBJECT to file
• Cleaned project
• Ran qmake
• Rebuild

it compiles fine.

Answer 2

Got the same error. I had a private slot declared in a .h file, but I didn't have it defined in my cpp file. I removed my unused slot in both places, and it compiled.

Answer 3

This happened to me when merging Qt code from one platform to another. I just resolved it, after much trial and error, so I'm posting it here since my issue was different. If you are merging new files, you can't just merge the files and the .Pro file and expect that they'll show up in Qt Creator for compilation. Notice your new files aren't actually being displayed in the IDE under your folders. I overlooked this, and was just looking at the folder structure and .Pro file. Once I manually added all of the files in Qt, it compiled fine. Here is how I figured this out:

1. Right click on the vague "symbol(s) not found for architecture x86_64" error, and select Compiled Output
2. At the bottom it will show what method(s) it can't find. Find what file(s) those methods are in, and add those headers and class files, by right clicking the folder they should be in the IDE, and selecting "Add Existing File"
3. Build, or Clean then Build