On Thursday 01 May 2008, Giovanni Bajo wrote: > On Wed, 2008-04-30 at 22:18 +0200, Aaron Digulla wrote: > > Phil Thompson schrieb: > > >> - For everything derived from QObject, connect to the dispose signal. > > >> At this time, save a stack trace and a pointer to the Python handle > > >> associated with the QObject > > >> - When the signal is emitted, make sure that the usage count of the > > >> corresponding Python object is 0, too. If it isn't, print the saved > > >> stack trace and a new one saying that the usage count between Python > > >> and C++ is out of sync. > > >> > > >> For the installation, the debug versions of the libraries should go > > >> into special directories so I can put them in the PATH (Windows) or > > >> the LD_LIBRARY_PATH (Linux) to select them when my code behaves odd. > > > > > > I'm not sure what that gives you. I would imagine that a QObject > > > disappearing while there is still a Python wrapper for it is quite > > > common and legitimate. For example, if you keep a reference to a child > > > object and the parent gets destroyed. The problem is only when you try > > > and use that reference - but if you do then you will get an exception > > > anyway. > > > > I get a core dump and on Windows, I get nothing. Even if I could get a > > core file, it wouldn't tell me where the object was created. > > > > So maybe the trick would be to declare the Python object as "invalid" as > > soon as the dispose signal was received. After that, any call to any > > method should raise an exception. > > This is exactly what PyQt (or rather SIP) does, for every Python wrapper > of a PyQt object. Whenever the QObject dies, the Python object is > flagged as invalid, and any usage of it results in a RuntimeError; > moreover, you can check for this invalid condition through > sip.isdeleted(). > > Thus, I'm not sure what you are speaking of.
I nearly gave the same reply, but realised I was wrong. The above is true only for QObjects created from Python because the death of the QObject is detected by the virtual dtor not by the destroyed() signal. Phil _______________________________________________ PyQt mailing list PyQt@riverbankcomputing.com http://www.riverbankcomputing.com/mailman/listinfo/pyqt
