[Spice-devel] [PATCH spice-gtk] Add call of gst_deinit at program exit

[Daniel P. Berrange]

On Thu, Oct 19, 2017 at 08:03:00AM -0400, Frediano Ziglio wrote:
> > 
> > 
> > In fact non-trivial shared libraries should generally never be unloaded, even
> > if they were originally dlopend.  If the library has used a pthread local
> > with
> > a destructor function, then unloading the library will remove the code that
> > contains the impl of the destructor. When the thread later exits and its
> > thread
> > locals are cleaned up, the application will crash & burn.
> > 
> > Many libraries, including libvirt, will link with '-z nodelete' to prevent
> > unloading of the library even if dlclose() is called, to avoid these kind
> > of crashes.
> > 
> > IOW getting perfect "cleanup" is just a fools errand and will likely create
> > obscure problems down the road that are worse than the problems the cleanup
> > is trying to solve. Just accept normal process resource cleanup when the
> > application exits.
> 
> This is a point for Windows... they manage to have unloading working.
> Also you can unload Linux kernel modules.
> I honestly find these reasoning a lazy excuse to bad programming and design.

Calling it laziness is completely missing the point. There is *nothing*
in the pthreads API that lets you avoid the problem with thread local
destructors described above, no matter how much we want to fix it. The
only "solution" is to not use pthread locals at all, which is not practical.


Regards,
Daniel
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