minutes of ESC call ...

[Stephan Bergmann]

On 02/03/2012 15:45, Stephan Bergmann wrote:
> I've never given much thought to dynamic_cast vs. XUnoTunnel (at least I 
> don't remember right now I ever did; searching old mail archives would 
> probably prove me wrong) -- to me XUnoTunnel was always that rarely 
> needed hack where the notational overhead doesn't really hurt.  But 
> sure, for the UNO wrappers in the application layers things look 
> different.  Anyway, thinking about it now, I see no reason one could not 
> use dynamic_cast instead of XUnoTunnel in the scenario outlined above.

Took me ten years to find the reason again why XUnoTunnel cannot be 
replaced with dynamic_cast, in general.  :)  See 
<https://gerrit.libreoffice.org/c/core/+/144139> "New loplugin:unocast": 
  "Find uses of dynamic_cast that cast from a UNO interface type. 
Unless it is known that the dynamic_cast must succeed, it can cause a 
crash:  If the source object is a proxy from the C++ UNO bridge, its 
vtable's RTTI slot will normally not be set up (see e.g. the 
ENABLE_RUNTIME_OPTIMIZATIONS code in 
bridges::cpp_uno::shared::VtableFactory::initializeBlock in 
bridges/source/cpp_uno/gcc3_linux_x86-64/cpp2uno.cxx)."