#include <QCoreApplication>
#include <functional>

struct ObjectNameSlot
{
    QString name;

    void operator() (const QString &objectName)
    {
        name = objectName;
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    ObjectNameSlot slot;
    QObject::connect(&a, &QCoreApplication::objectNameChanged, std::ref(slot));

    a.setObjectName("A");

    Q_ASSERT(slot.name == "A");

    return a.exit(0);
}