class CustomKeyCatcher: public QThread {
public:
    explicit CustomKeyCatcher(QObject* parent = nullptr)
        :QThread{ parent } {}
    void interruptAndWait() {
        requestInterruption();
        wait();
    }
protected:
    virtual void run() override {
        while(not isInterruptionRequested()) {
            const auto symbol = getchar();
            std::cout << "Key pressed: " << symbol << std::endl;
        }
    }
};

int main(int argc, char** argv) {
    QCoreApplication app{ argc, argv };

    auto catcher = new CustomKeyCatcher{ &app };
    QObject::connect(&app, &QCoreApplication::aboutToQuit, catcher, &CustomKeyCatcher::interruptAndWait);
    catcher->start(QThread::Priority::LowestPriority);

    return app.exec();
}