title: Undefined reference in simple Qt program
body: <p>I'm a beginner making a program in Qt creator. I made a button that should open Google Chrome using <code>QtProcess::execute()</code>, but I'm getting following errors:</p>
  
  <pre><code>F:\Users\Amol-2\Desktop\Imp Docs\C++ apps\build-QtMainLProject-Desktop_Qt_5_2_0_MinGW_32bit-Debug\debug\moc_mainwindow.cpp:71: error: undefined reference to `MainWindow::buttonClickHandler()'`
  :-1: error:  ld returned 1 exit status
  </code></pre>
  
  <p><strong><code>mainwindow.cpp</code>:</strong></p>
  
  <pre><code>#include "mainwindow.h"
  #include "ui_mainwindow.h"
  #include &lt;QProcess&gt;
  
  MainWindow::MainWindow(QWidget *parent) :
      QMainWindow(parent),
      ui(new Ui::MainWindow)
  {
      ui-&gt;setupUi(this);
  }
  
  MainWindow::~MainWindow()
  {
      delete ui;
  }
  
  
  void MainWindow::on_openChrome_clicked()
  {
      QString exeloc = "F:\\Users\\Amol-2\\AppData\\Local\\Google\\Chrome\\Application\\chrome.exe";
      QProcess::execute(exeloc);
  }
  </code></pre>
  
  <p><strong><code>mainwindow.h</code>:</strong></p>
  
  <pre><code>    namespace Ui {
  class MainWindow;
  }
  
  class MainWindow : public QMainWindow
  {
      Q_OBJECT
  
  public:
      explicit MainWindow(QWidget *parent = 0);
      ~MainWindow();
  
  public slots:
      void buttonClickHandler();
  
  
  public slots:
      void on_openChrome_clicked();
  
  private:
      Ui::MainWindow *ui;
  };
  </code></pre>
  
  <p>What am I doing wrong?</p>