Re: [boost] [Review] optional exceptions

From: Ion Gaztañaga (igaztanaga_at_[hidden])
Date: 2006-02-12 15:34:23

>>> and AFAIK it's impossible to implement zero-overhead stack unwinding
>>> (you're the exception expert, so please correct me if I'm wrong).
>> If by "zero-overhead stack unwinding" you mean exception handling that
>> has no speed cost unless an exception is thrown, then consider
>> yourself corrected.
> 
> This means that it is impossible to implement stack unwind with no
> speed cost when an exception is not thrown?
> I'm definitely not an expert, not even a newbie in this field
> probably, but I thought it was possible.
> Or did I misunderstood your statement?

I don't know anything about exception implementation, but I suppose that 
the code must mark some "check-points" to know how many object are 
already constructed, to know how many destructors it must call when the 
exception occurs. I suppose that can be implemented as an 
integer/pointer increment or assignment. But the code must add something 
to the normal path to know what to do when the exception occurs.

Regards,

Ion