[Interest] BRe: can the QRegExpEngine cache acces objects belonging to an unloaded library during global destruction?

Thiago Macieira thiago.macieira at intel.com
Wed Jan 31 16:19:17 CET 2018

On Wednesday, 31 January 2018 07:13:53 PST René J. V. Bertin wrote:
> > You have the symptom of QBasicMutex containing garbage. It is thinking the
> > mutex is locked.
> Right. Or not, and then trying to lock it upon my request. Using
> uninitialised variables is kind of UB too, no? 

Correct. You can copy uninitialised values if you use byte-level access, so 
memcpy is allowed, but you can't make decisions using them.

> > QMutex as a member variable in the class is fine too. Just don't make it
> > static.
> Why would I do that? Moving the mutex into the class only makes sense if you
> want to be able to lock different instances independently; making it a
> static member wouldn't change anything w.r.t. to current code, in practice.

If you only have one instance, then having it inside the class means you still 
have only 1.

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel Open Source Technology Center

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