What is this?

[bobef]

Sean Kelly Wrote:

> Lars Ivar Igesund wrote:
> > bobef wrote:
> > 
> >> Hey guys,
> >>
> >> do you know what is this and could cause it?
> >> "An exception was thrown while finalizing an instance of class whatever".
> > 
> > I believe it means an exception is thrown in a destructor or similar (and
> > afaik a Tango feature).
> 
> This is exactly right.  Throwing an exception from a dtor constitutes a 
> programming error and Tango attempts to discourage this by handling it 
> in much the same way as an assertion failure.  The exception is wrapped 
> in a FinalizeException before passing it up the stack.  This is one of 
> the few (or perhaps the only) place in the Tango runtime where I decided 
> to actually restrict legal programming behavior.  One reason for this is 
> that currently, multiple in-flight exceptions will not terminate a D 
> application--one will simply replace the other (this could be changed in 
> the runtime as well but I haven't done so yet).  Another is that it's 
> nearly impossible to write correct code if dtors are allowed to throw. 
> C++ uses the no-throw spec for dtors in the STL for this reason, and I 
> believe that "encouraging" the same behavior in user code is worthwhile.
> 
> 
> Sean

Thanks.