[Qt5-feedback] new Qt5 - great! - but: What about exceptions?

[Thiago Macieira]

On Monday, 16 de May de 2011 11:22:41 André Pönitz wrote:
> - Qt code right now is not exception safe. "Fixing" that is a huge effort. 
> You can easily sink a few months of work here. A few of the "maintainer 
> wanted" items take significantly less effort, so from my point of view any 
> free capacities you might have would be spent better otherwise.

What we agreed during the Symbian port times was:

 - full exception safety on the Qt container classes, like QVector, QList, 
etc.

 - have the event loop cleanly exit if an exception is thrown from inside. If 
we can't propagate through third-party code, catch the exception, consume it 
and throw a generic one from Qt code again. (except for std::bad_alloc, that 
should be rethrown as-is) Restarting the event loop after an exception was 
leaked through it is undefined behaviour.

   Note that I've got some work that stops trying to catch the exception, but 
simply lets it propagate through. (No catch {} blocks)

 - this includes the signal-slot mechanism too

 - the rest of the classes as exception-unsafe and may crash or freeze if an 
unexpected exception is thrown (including std::bad_alloc)


-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Senior Product Manager - Nokia, Qt Development Frameworks
      PGP/GPG: 0x6EF45358; fingerprint:
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