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

18
votes

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!

9
c++qt
Can you include the full error, i.e. what symbols were not found please? – je4d
Do you know about moc? If the classes don't get moced correctly you can have link problems. Try building with qmake from command-line. – Andrew Tomazos
I added even more detail about the error. But I do not know about moc. If you say the error comes from the linker I will use it. – Jonathan Bibas
I have also run into this problem while messing around with Qt+OpenCV and an undefined yet declared slot was my problem too, like Jonathan's. It is easy to miss because the slot codes are generated through mouse clicks in the designer. Thanks, Jonathan for the solution. (I can't vote up yet.) – Barney Szabolcs
@JonathanBibas, I just ran into same problem with Qt Creator, adding #include "MyWindow.moc" at the end of MyWindow.cpp solved it, does that work for you? – lazyboy

9 Answers

15
votes

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.

12
votes

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.

4
votes

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
2
votes

CONFIG -= x86_64 fixed this problem for me

2
votes

This can happen, when you forgot the Class-Operator, when defining your function.

H File:

class Globals
{
public:
    unsigned int myFunction();

};

CPP File:

unsigned int Globals::myFunction(){return 3;}
1
votes

I found the answer finally! (for whoever will be interested)

The mistake is that I shouldn't have extended the class QPushButton, to customize my button, but rather, create my own class HexButton extending/inheriting the QWidget class! Doing so we must add to the button, a QPushButton instance. Well it then makes: 

 class HexButton : public QWidget
 {

 Q_OBJECT

 public:
     HexButton(QWidget *parent = 0);

 public slots:
    void changeIcon();

 private:
    QPushButton *button;

  };
0
votes

Move the slot changeIcon() into HexButton class from MyWindow class.

0
votes

Normally this happens with Qt because of your build system - it indicates that you're not compiling/linking in the code generated by moc

I'm pretty sure that there's nothing wrong with your code - so the error must be in some setting in qt creator, which I can't really help with as I've not used it much.

If you haven't already, you could try adding an explicit empty destructor declaration to hexbutton.hpp and definition to hexbutton.cpp. It shouldn't be necessary, but I've heard of this making a difference on some quirky compilers/linkers.

0
votes

try to remove pro.user file and reimport project with any qt 32bit kit.