Problems with Qt 4.6 in VS 2008

Question

sys info : win xp SP3 , Microsoft Visual Studio 2008 Version 9.0.21022.8 RTM

Microsoft .NET Framework Version 3.5 SP1

Qt Add-in 1.1.5

I installed Qt 4.6.3 from the site http://qt.nokia.com/downloads/windows-cpp-vs2008. Then I added the Add-in Qt 1.1.5 and configured the PATH variable.

When I open a new QT project , default example works just fine.

On Nokia (qt) site I found some examples but it seems that things are not working properly.

Here is one of many examples that do not work :

#include <QtGui>
#include <QWidget>

 class QLabel;
 class QLineEdit; 
 class QTextEdit;


class AddressBook : public QWidget
 {
     Q_OBJECT

 public:
     AddressBook(QWidget *parent = 0);

 private:
     QLineEdit *nameLine;
     QTextEdit *addressText;
 };

AddressBook::AddressBook(QWidget *parent)
     : QWidget(parent)
 {
     QLabel *nameLabel = new QLabel(tr("Name:"));
     nameLine = new QLineEdit;

     QLabel *addressLabel = new QLabel(tr("Address:"));
     addressText = new QTextEdit;

     QGridLayout *mainLayout = new QGridLayout;
     mainLayout->addWidget(nameLabel, 0, 0);
     mainLayout->addWidget(nameLine, 0, 1);
     mainLayout->addWidget(addressLabel, 1, 0, Qt::AlignTop);
     mainLayout->addWidget(addressText, 1, 1);

     setLayout(mainLayout);
     setWindowTitle(tr("Simple Address Book"));
 }

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

     AddressBook addressBook;
     addressBook.show();

     return app.exec();
}

Compiler says this ::

Output Window

Linking...

main.obj : error LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __thiscall AddressBook::metaObject(void)const " (?metaObject@AddressBook@@UBEPBUQMetaObject@@XZ)

main.obj : error LNK2001: unresolved external symbol "public: virtual void * __thiscall AddressBook::qt_metacast(char const *)" (?qt_metacast@AddressBook@@UAEPAXPBD@Z)

main.obj : error LNK2001: unresolved external symbol "public: virtual int __thiscall AddressBook::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@AddressBook@@UAEHW4Call@QMetaObject@@HPAPAX@Z)

main.obj : error LNK2001: unresolved external symbol "public: static struct QMetaObject const AddressBook::staticMetaObject" (?staticMetaObject@AddressBook@@2UQMetaObject@@B)

C:\Documents and Settings\nik\My Documents\Visual Studio 2008\Projects\vs_03\Debug\vs_03.exe : fatal error LNK1120: 4 unresolved externals

Results

Build log was saved at "file://c:\Documents and Settings\nik\My Documents\Visual Studio 2008\Projects\vs_03\vs_03\Debug\BuildLog.htm" vs_03 - 5 error(s), 0 warning(s)

It seems to me that the thing has to do with the use of macro Q_OBJECT but just dont know what to do that thing starts to work properly.

Maybe wrong installation or ... NO IDEA

Any help is appreciated.

Appears to be MOC related. Make sure the MOC is producing a matching moc_.cpp file for this sample. If it is, make sure that moc_.cpp file is added to the project. — stinky472
Do you have experience with VS2008-Qt? Do you have any explanation in a few steps? — nik_02
Apologies, unfortunately not. I do most of that stuff from the command line so my suggestion would be analogous to Timo's. — stinky472

Timo Geusch Timo Geusch · Accepted Answer · 2010-06-29T23:35:50

I don't think it's a wrong installation - I assume you're using Visual Studio to build the project and in that case, you also need to tell it to build the _moc.cpp files that should have been generated for your class AddressBook.

If they haven't been generated you also need to run moc on the header files for AddressBook.

Problems with Qt 4.6 in VS 2008

3 Answers