release/main.o:main.cpp:(.text+0xcb): undefined reference to `vtable for MClas'
collect2: ld returned 1 exit status

#ifndef _Main_h_
#define _Main_h_

#include <QObject>

class MClas : public QObject {
    Q_OBJECT
public:
    MClas() : QObject() { }
    QWidget      wgt;
public slots:
    void ShowKvadr();
    void MClock();
    void Pict();
};
#endif

#include <QtGui>
#include "main.h"
//-------
  MClas *Mc;
// --------------------------------
int main(int argc, char** argv)
{
    QApplication app(argc, argv);
    Mc = new MClas();
    QPushButton B1("1", &Mc->wgt);
    QPushButton B2("2", &Mc->wgt);
    QPushButton B3("2", &Mc->wgt);
    QObject::connect(&B1, SIGNAL(clicked()),
                     Mc, SLOT(ShowKvadr()));
    QObject::connect(&B2, SIGNAL(clicked()),
                     Mc, SLOT(MClock()));
    QObject::connect(&B3, SIGNAL(clicked()),
                     Mc, SLOT(Pict()));
    Mc->wgt.resize(800, 600);
    Mc->wgt.show();
    return app.exec();
}
/**************/
void MClas::ShowKvadr()
{
}
/******************/
void MClas::MClock()
{
}
/******************/
void MClas::Pict()
{
}
/[code]