Qt signaling across threads, one is GUI thread?

Question

What does it mean to move a object from one thread to another in Qt using moveToThread? Everything seems to work even before using moveToThread, which moves the object from

Answer 1

2. The QThread::start() method creates the thread and calls your run() implementation. If you want to handle events or received signals on the thread you have to call QThread::exec() inside your run() implementation. You should never call run() explicitly and you should never call exec() outside of run().

3. The owner thread makes a difference only when a slot is connected to a signal with the connection type other than Qt::DirectConnection. Then Qt will ensure that the slot runs on the owner thread, but for that the owner thread must be running an event loop with QThread::exec(). In this case calling myObj.moveToThread(myThread) will ensure that myObj slots run on the thread myThread.

4. The thread object belongs to the thread where it was created, not on the thread that it manages (and where the run method will run). So when you connect a signal to a thread object's slot, that slot will run in the thread where the thread object was created unless you call moveToThread().