Qt application with multiple threads

Question

I have a QT application.

I have a thread (ex thread1 ) that shows my mainwindow (so this is different from the main thread).

I also have my own thread (ex thread2 ) must notify the thread1 updating my GUI. There is a quick way to do this? ex: thread2 may decide to update an image: so, he shall notify the thread1 to perform the method changeImage() .

If I do run this method directly from thread2 my application will have a crash. I must to use pthread.

Answer 1

Only the main thread should update the GUI (for restrictions due to graphical systems).

However, Qt has enhanced thread support allowed by signal-slot connections across threads. In facts, the other threads have to notify the main thread using signals ( emit my_signal() see http://qt-project.org/doc/qt-4.8/signalsandslots.html ) or using QCoreApplication::postEvent ( http://qt-project.org/doc/qt-4.8/qcoreapplication.html#postEvent-2 )