[PyQt] A Qt error pushed me out of Python

[Matt Newell]

On Friday 13 April 2007 09:43, Gerard Vermeulen wrote:
> If you are using a version of PyQt before 4.2, you cannot really use
> PyQt widgets like this because they do not respond to events, since
> their is no event loop (you did not call yourQApplication._exec()).
> PyQwt has a module 'iqt' that fakes an event loop in combination with
> the readline module, see
> http://pyqwt.sourceforge.net/doc5/iqt-intro.html
>
> I think that PyQt-4.2 has also half the facility of faking the event
> loop: you still have to use the readline module (this is what I think,
> I did not test it) to make sure that events are handled.
>
> Anyhow, if you want to use PyQt from the interpreter, I recommend
> the use of a Python startup file as explained in iqt-intro.html.
>
> Regards -- Gerard
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You don't need to call QApplication::exec to have an event loop.  A local 
event loop is created automatically whenever you call QMenu::exec, 
QDialog::exec or one of the static QMessageBox methods.  You still need a 
QApplication of course.

Try this to see

from PyQt4 import QtGui
import sys
app = QtGui.QApplication(sys.argv)
QMessageBox.critical(None,"Hello","World")

control returns to the caller after the message box is closed.

Matt