Qt 5.0 [ui_mainwindow.h] Error -1073741515 - c++

Question

I have a problem with Qt 5.0 as when I execute any simple code I have this error from linker.
-1: error: [ui_mainwindow.h] Error -1073741515
I'd like to know how to solve it.
This is the causing code snippit:
#include "mainwindow.h"
#include <QtGui/QApplication>
#include <QLabel>
int main(int argc, char *argv[]) {
QApplication prog(argc, argv);
QLabel *label = new QLabel("GameTime!");
label->show();
return prog.exec();
}

Answer 1

Your QLabel *label and show() code need to go in mainWindow.cpp
Your main.cpp should look like:
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
And your mainwindow.cpp (something like this)
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
QLabel *label = new QLabel("GameTime!");
label->show();
}
I didn't test this exact mainwindow code, but it should be pretty close. I usually use the user interface builder that QT Creator comes with to access UI elements.

Answer 2

You did not enclose what development environment you are using, but assuming it uses MS linker cl.exe, it is highly assumably that the environment variables aren't set correctly.
This error is caused, if cl.exe is started on command line or from within a build script and can't find its needed mspdb80.dll in the path.
To avoid this, just make sure to set the environment properly. For MS VS2010 for example you would have to call
C:\RANDOM\PATH\>"%VS100COMNTOOLS%vsvars32.bat"
%VS100COMNTOOLS% is usually set by VS2010 installer on setup. If you are using a different version, that will be %VSx0COMNTOOLS% with x could be 5, 6,... according to your version of Visual Studio.
Output should be something like this:
Setting environment for using Microsoft Visual Studio 2010 x86 tools.