[Interest] Possible memory leak in QXmlStreamReader

Marc Schmitzer marc.schmitzer at richard-wolf.com
Wed Nov 7 17:07:23 CET 2012

Hello everybody,

we discovered a potential memory leak with an (admittedly somewhat 
unusual) use of QXmlStreamReader.

Before reporting this as a bug, I wanted to get some opinions on whether 
this really is a bug or if we're just mis-using the interface.

I've appended a code snippet that triggers the bug. Note that this runs 
a tight loop, so you might want to at a sleep() somewhere to avoid 
stalling your machine.

When run, the virtual image size of the program quickly increases.

Qt version is 4.8.1 as currently provided by ubuntu for the "precise" 
release (4.8.1-0ubuntu4.2), platform is 32 bit Ubuntu 12.04.

#include <QString>
#include <QXmlStreamReader>

int main()
   const QString xml = "<test><foo>bar</foo><bazz>frobozz</bazz></test>";

   QXmlStreamReader stream;

   while (true)

       while (stream.readNextStartElement())
       // NOP

   return 0;

Mit freundlichen Gruessen / Best regards

Marc Schmitzer

SW-Entwicklung ESWL / ESWT
Software development ESWL / ESWT


Richard Wolf GmbH

Pforzheimer Strasse 32

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Tel.:         +49 7043 35-1107
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Email:        marc.schmitzer at richard-wolf.com
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