Q about staticvec declaration

Q about staticvec declaration

[Gerd Möllmann]

Can someone please explain why staticvec is declared as

  Lisp_Object const *staticvec[NSTATICS]

which is the same as

  const Lisp_Object *staticvec[NSTATICS]

? 

Re: Q about staticvec declaration

[Mattias Engdegård]

27 mars 2024 kl. 10.38 skrev Gerd Möllmann <gerd.moellmann@gmail.com>:

> Can someone please explain why staticvec is declared as
> 
>  Lisp_Object const *staticvec[NSTATICS]
> 
> which is the same as
> 
>  const Lisp_Object *staticvec[NSTATICS]

That's just a matter of individual handwriting, there's nothing more to it.
I think we can tolerate either.

Re: Q about staticvec declaration

[Gerd Möllmann]

On 27.03.24 12:44, Mattias Engdegård wrote:
> 27 mars 2024 kl. 10.38 skrev Gerd Möllmann <gerd.moellmann@gmail.com>:
> 
>> Can someone please explain why staticvec is declared as
>>
>>   Lisp_Object const *staticvec[NSTATICS]
>>
>> which is the same as
>>
>>   const Lisp_Object *staticvec[NSTATICS]
> 
> That's just a matter of individual handwriting, there's nothing more to it.
> I think we can tolerate either.
> 
You mean the "type const" vs. "const type"? I agree that doesn't matter 
much.

What I meant to ask is why are the Lisp_Objects considered const when 
viewed through staticvec. I mentioned the other form in case it weren't 
clear that both are the same. I mean, the staticpro'd variables are 
clearly non-const.

Re: Q about staticvec declaration

[Mattias Engdegård]

27 mars 2024 kl. 13.15 skrev Gerd Möllmann <gerd.moellmann@gmail.com>:

> What I meant to ask is why are the Lisp_Objects considered const when viewed through staticvec.

Oh, I see. No idea, but it's not obvious that all static roots are free game for a moving GC (for example, there could be other references that expect the static roots to remain unchanged for all I know).

Re: Q about staticvec declaration

[Gerd Möllmann]

On 27.03.24 13:54, Mattias Engdegård wrote:
> 27 mars 2024 kl. 13.15 skrev Gerd Möllmann
> <gerd.moellmann@gmail.com>:
> 
>> What I meant to ask is why are the Lisp_Objects considered const
>> when viewed through staticvec.
> 
> Oh, I see. No idea, but it's not obvious that all static roots are
> free game for a moving GC (for example, there could be other
> references that expect the static roots to remain unchanged for all I
> know).

Yes, that's what I'm trying to understand, if there is something that 
depends on that. Without success, so far.

But it could also be a mistake, of course. Something like "const *" 
where "* const" was meant. Who knows...