[Xcb] problem with xcb-based Xlib and multithreaded applications

Francesco Abbate francesco.bbt at gmail.com
Tue Jan 4 08:29:51 PST 2011

2011/1/4 Uli Schlachter <psychon at znc.in>:
> I just made this use XSync(d, True) and managed to make this hang (it worked for
> a moment at first). Don't ask me how I managed to do this, it didn't hang on the
> second try.
> Then I removed all the "sleep(1);" which makes it freeze almost immediately,
> even with Discard=False.

Thank you Uli, we have easily obtained a perfect test case for this bug :-)

> Now find someone who has a clue about Xlib and can figure out why this hangs, I
> can only speculate.

I hope we will get some help from the people that know the
implementation details of the Xlib.

Otherwise, I would like to remember that, in my email, I'm talking
also about a second error, a BadDrawable X error that I can get if I
do XCloseDisplay in a connection that still have some outgoing drawing
events. I can workaround this problem with a XSync before the
XCloseDisplay but I'm wondering if it is a normal behaviour or it is a
bug, and if it is related to the xcb implementation.

When these two problems will be solved may be I will give the details
about a memory leak introduced by the xcb-based Xlib implementation,
but this is a minor problem.


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