Comment 7 for bug 753269

@Ugo

Thanks for the explanation. I need to go back and study the code further to fully understand.

I saw the Q_CHECK_PTR() in the Qt code against the X call returning a null pointer and I agree it does seem wrong. You end up with a C++ 'bad alloc' exception which is misleading as it doesn't really reflect what had happened. I tried to find out how you check for X errors after a call like XGetImage() has failed, but with no luck. I was expecting to find something like errno, or a call you can make to get the last X error. I didn't find anything logged in the ~/.xsession-errors log either.

I've been going through the Unity-2d bug reports to try and find something I can work on, and I noticed several of them were crashes as a result of X errors. I wonder if they have a common cause related to coordinating X calls with Unity-2d workspace management, like this bug.

I did expect the spread to handle drag and drop between workspaces, and that will be a better way of moving windows than using a menu option on the title bar.