Multithreading with QtDBus

Ogden, Nick nick.ogden at
Thu Nov 1 07:14:11 PDT 2012


I have a program that does the following:
1) Creates a QCoreApplication
2) Creates a third party component (read: black box) which internally spawns multiple threads
3) Creates a QDBusConnection and connects to some DBus signals
4) Enters the main Qt event loop

>From here onwards, the third party black box makes calls, on whatever thread it feels is appropriate, to some handler functions in the application, that are required to retrieve some data via DBus. Each thread creates its own proxy object and makes a blocking call over DBus by means of QDBusPendingReply::waitForFinished(). These proxy objects share the same underlying QDBusConnection object.

My first question is whether or not this usage scenario is supported / expected to work with QtDBus?

I am experiencing frequent crashes from deep in libdbus-1 when running this application on Windows (I have not tested on Linux etc). I have attached a small test case which is representative of the usage scenario and reproduces this crash 100% of the time. Could someone please confirm whether this is a bug, or an unsupported use case for QtDBus and I will file a bug report as appropriate.

Kind Regards
Nick Ogden
Software Engineer
G4S Technology Ltd.

nick.ogden at<mailto:nick.ogden at><>
Challenge House,
International Drive,
GL20 8UQ, UK

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