Re: [boost] [Review] Shmem

From: Tobias Schwinger (tschwinger_at_[hidden])
Date: 2006-02-10 20:17:33

Fred Bertsch wrote:
>>I don't like that 1-hack for the NULL values in offset_ptr and I don't understand
>>why it's necessary. If NULL is outside the memory segment -- so what? NULL
>>should never be dereferenced anyway... There should be a "just works" solution
>>and there's no need for parametrization, here. Maybe I don't understand the
>>problem correctly.
> 
> 
> That's a good point. Is it possible to have a null offset_ptr point to
> NULL? (-this, essentially) It might not be. I can imagine potential
> problems with this on a CPU architecture that placed registers near 0,
> though.
> 

You mean hardware registers like vector interrupts? Well if you don't dereference there's no problem and if you dereference you have to debug anyway...

But my suggestion has a very fundamental flaw:

When an offset pointer in process a sets the offset to '-this' (resulting in NULL), then the offset pointer in process b would add his (very own) 'this' and *not* get NULL.

Sorry for my stupidity attack,

Tobias