Wait for some signal c++ QT source:https://stackoverflow.com/questions/41121932/what-is-the-simplest-way-to-make-your-program-wait-for-a-signal-in-qt

QT QeventLoop

QEventLoop loop;
    connect(this, &SomeObject::someSignal, &loop, &QEventLoop::quit);
    // here you can send your own message to signal the start of wait, 
    // start a thread, for example.
    loop.exec(); //exec will delay execution until the signal has arrived