Re: valid_pointer_p

[Eli Zaretskii <eliz@gnu.org>]

> Cc: emacs-devel@gnu.org
> From: storm@cua.dk (Kim F. Storm)
> Date: Sat, 12 Aug 2006 00:58:05 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Well, I figured that much.  But we do know the length of each object,
> > so we could validate exactly what is needed, right?  Just add another
> > argument to valid_pointer_p that tells it how many bytes to validate.
> 
> The problem is that you have to deref the pointer to know the length
> of the object...

??? Don't we have macros, like INTEGERP, SUBRP, etc. to do that
without dereferencing?  The length of the primitive Lisp types is
known, right?

Even if you are right, dereferencing a pointer accesses a region in
memory whose length is known in advance, so at most we will need to
call valid_pointer_p twice.