main.cpp

#include <QApplication>
#include <QtWidgets>
#include "TDialog.hpp"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QPushButton w;
    TDialog d(&w);

    w.show();
    QObject::connect(&w, &QPushButton::clicked, [&d]() {
            d.exec();
        });

    return a.exec();
}