#include <QLabel>
#include <QDebug>
#include <QDialog>
#include <QHBoxLayout>
#include <QApplication>

class MyDialog : public QDialog {
public:
    MyDialog() {
        setFixedSize(400, 300);

        auto label = new QLabel(this);
        label->setText("Very long long long text. Very long long long text. Very long long long text. Very long long long text.");
        label->setWordWrap(true);

        auto mainLayout = new QHBoxLayout(this);
        mainLayout->addWidget(label);
    }
};

int main(int argc, char *argv[]) {
    QApplication::setAttribute(Qt::AA_DisableHighDpiScaling, true);

    QApplication a(argc, argv);

    MyDialog w;
    w.show();

    return a.exec();
}