[PyQt] Easy Segfault using (or misusing) QTextStream

David Cortesi davecortesi at gmail.com
Thu Aug 15 22:26:58 BST 2013

I had the problem that this sequence crashed Python:

 >>>> from PyQt4.QtCore import (Qt, QString, QTextStream)
> >>>> ts = QTextStream(QString())
> >>>> ts << u'x'
> > Segmentation fault

Phil properly reminded me that,

> You need to keep a reference to the QString.

And I thought, oh crap, another didn't-keep-a-ref bug. I'm a dope.

But later it occurs: this is a great nuisance, because what I want to do is
to call a function that returns a QTextStream ready to read. Maybe it is
based on a file, or maybe it contains some boilerplate generated on the fly
-- The latter being an in-memory stream created as above.

So this function either has to have access to a global QString, or the
caller has to pass a QString for it to use in case it needs one, or the
function has to return a tuple (stream,
QString-it-may-or-may-not-be-based-on) and the caller has to keep the
string in scope.

It would be much cleaner if the QTextStream(QString) constructor could take
parental ownership of the QString it is passed. There is no question about
its being related to the new object and essential to it. Would this be a Qt
enhancement or a PyQt one?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.riverbankcomputing.com/pipermail/pyqt/attachments/20130815/3fb6e72e/attachment.html>

More information about the PyQt mailing list