[PyQt] Signal/slot bug when doing multiple connects and Qt::UniqueConnection
giuseppe.corbelli at copanitalia.com
Mon Apr 28 10:39:46 BST 2014
On 28/04/2014 09:26, Giuseppe Corbelli wrote:
> Hi all
> I've run into an "interesting" side effect, admittedly misusing the
> signal-slot mechanism. Basically I'm doing multiple connections using the
> Qt::UniqueConnection parameter. As expected the slot is run always a single
> time, but there's something weird going on in the background. The receivers()
> method returns increasing numbers and this little example will kill the CPU in
> a few iteractions.
multiple calls to:
run without errors if the slot is NOT decorated with pyqtSlot.
This is the case of the example just posted.
If the slot is a @pyqtSlot() the second call fails with a TypeError exception
but the number of QObject::receivers() stays 1 and the program performs as
expected. See below an example that performs correctly (or at least it seems
so) just using the decorator.
# -*- coding: utf-8 -*-
from PyQt4 import QtCore
logger = logging.getLogger('blah')
mysignal = QtCore.pyqtSignal()
assert(self.receivers(self.mysignal.signal) == 1)
app = CApp(sys.argv)
t = QtCore.QTimer()
WASP Software Engineer, Copan Italia S.p.A
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E-mail: giuseppe.corbelli at copanitalia.com
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