[Development] HEADS-UP: QStringLiteral

Thiago Macieira thiago.macieira at intel.com
Wed Aug 21 19:38:17 CEST 2019

On Wednesday, 21 August 2019 09:44:55 PDT Tor Arne Vestbø wrote:
> I have to double check the dyld sources, but in many cases the dlclose will
> be a no-op, and the image won’t actually unload. One of these conditions
> was (if I recall correctly) if the library had any thread local storage.

Oh, that's an interesting trick, yeah. Pretty sure all systems will have a 
similar issue, since C++11 thread_local requires that non-PODs be 
destructible, which means the system needs to know that the destructor is 
still present when the thread exits.

If they don't, then it's going to possibly crash the same way that 
QStringLiteral today does.

PS: this is also why we can't use thread_local in Qt 6 just yet. MinGW does 
not support those with non-trivial destructors.

PPS: can we drop MinGW support in Qt 6?

Thiago Macieira - thiago.macieira (AT) intel.com
  Software Architect - Intel System Software Products

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