Windows Linking errors metaObject, qt_metacast and qt_metacall

jalway

Hello,

I'm compiling a QT project for OBS Studio. I'm on Windows 10 and am using Visual Studio 2022, coding with C++.

The project is here:obs-plugintemplate

I've added code to the project that implements QT. In their cmake file they allow you to turn on QT. I did this.

QT is installed by them, but when I compile their code it won't link.

I get these unresolved errors:

1>test.obj : error LNK2001: unresolved external symbol "public: virtual struct QMetaObject const * __cdecl TestWidget::metaObject(void)const " (?metaObject@TestWidget@@UEBAPEBUQMetaObject@@XZ)
1>test.obj : error LNK2001: unresolved external symbol "public: virtual void * __cdecl TestWidget::qt_metacast(char const *)" (?qt_metacast@TestWidget@@UEAAPEAXPEBD@Z)
1>test.obj : error LNK2001: unresolved external symbol "public: virtual int __cdecl TestWidget::qt_metacall(enum QMetaObject::Call,int,void * *)" (?qt_metacall@TestWidget@@UEAAHW4Call@QMetaObject@@HPEAPEAX@Z)
1>C:\Projects\temp\duanepugh\obs_intro\obs-exprplugin\build_x64\Release\obs-experiment-plugin.dll : fatal error LNK1120: 3 unresolved externals

Here is what my test.h file contains:

#include <QtWidgets/QDockWidget>
#include <QtWidgets/QPushButton>
#include <QtWidgets/QHBoxLayout>
#include <QtWidgets/QWidget>
#include <QtWidgets/QMessageBox>

class TestWidget : public QDockWidget
{
	Q_OBJECT
public:
	explicit TestWidget(QWidget *parent = nullptr);
	~TestWidget();

private:
	void buttonClicked();
	QWidget *parent = nullptr;
	QPushButton *button = new QPushButton();

private slots:
	void ButtonClicked();
};

And here is my test.cpp file contents:

#include "test.h"

TestWidget::TestWidget(QWidget *parent) : QDockWidget("My Plugin", parent)
{
	this->parent = parent;

	QWidget *widget = new QWidget();
	this->button->setText("Press Me!");
	QHBoxLayout *layout = new QHBoxLayout();
	layout->addWidget(this->button);

	widget->setLayout(layout);

	setWidget(widget);

	setVisible(false);
	setFloating(true);

	resize(300, 300);

	QObject::connect(button, SIGNAL(clicked()), SLOT(ButtonClicked()));
}

TestWidget::~TestWidget() 
{
}

void TestWidget::ButtonClicked()
{
	QMessageBox::information(this, "Info", "You clicked on a box!");
}

Any help would be appreciated.

Thanks!
...John

jalway

@jalway

Should there be a qmake.exe in by qt/bin folder?

in my qt bin folder I see moc.exe, qlalr.exe, qsb.exe, qtpath.exe, ptpaths6.exe, qvkgen.exe, rcc.exe, tracegen.exe and uic.exe, but I don't see qmake.exe.

I note that Qt VS Tools in Visual Studio 2022 requires that you find the path to that to connect to the version of QT you have installed, but I don't see qmake.exe there.

I got that from here:

Add Qt versions