signal/slot mechanism is totally independent of any GUI event loop

[twosnowman]

In Qt Documents about Signal/Slot, It says that "The signal/slot mechanism is totally independent of any GUI event loop" . How to comprehend this words? On my opinion, for example, if a user clicked a PushButton, the event loop will catch this event and a Clicked() signal will be sent ? If the connected slot will not return, the GUI　will be blocked. So I am mazed about this words.

[jacek]

In Qt Documents about Signal/Slot, It says that "The signal/slot mechanism is totally independent of any GUI event loop" .

It means that this mechanism will work even if you don't have a running event loop.

If the connected slot will not return, the GUI　will be blocked.

If you have only one thread, you can't execute different parts of your code simultaneously.

[wysota]

And not every signal is emited from an event handler.

[Codepoet]

It means that this mechanism will work even if you don't have a running event loop.

At least if you have multiple threads with queued connections this is wrong: Queued connections are only processed in the event loop: QThread::exec
But all this works without a GUI, use QCoreApplication instead of QApplication.

[jacek]

At least if you have multiple threads with queued connections this is wrong:

Provided that you use Qt4, unlike the author of this thread.