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Re: Lisp object that refers to a C struct
From: |
Eli Zaretskii |
Subject: |
Re: Lisp object that refers to a C struct |
Date: |
Thu, 18 Oct 2012 19:21:29 +0200 |
> Date: Thu, 18 Oct 2012 09:42:14 -0700
> From: Paul Eggert <address@hidden>
> CC: address@hidden
>
> On 10/18/2012 04:09 AM, Eli Zaretskii wrote:
> >> but in general it's not safe to convert a pointer to
> >> > an Emacs fixnum, as this can lose information: the payload
> >> > of an Emacs fixnum is typically narrower than a pointer.
> > A pointer that is properly aligned has no problem with this.
>
> It can have problems on hosts where USE_LSB_TAG is 0,
> because the conversion to Emacs fixnum can lose high-order
> bits in the pointer.
We are talking about Windows-specific code, so I don't think this
danger is real.
- Re: Lisp object that refers to a C struct, (continued)
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/17
- Re: Lisp object that refers to a C struct, Stefan Monnier, 2012/10/17
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/17
- Re: Lisp object that refers to a C struct, Paul Eggert, 2012/10/17
- Re: Lisp object that refers to a C struct, Stefan Monnier, 2012/10/17
- Re: Lisp object that refers to a C struct, Stephen J. Turnbull, 2012/10/17
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/18
- Re: Lisp object that refers to a C struct, Paul Eggert, 2012/10/18
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/18
- Re: Lisp object that refers to a C struct, Paul Eggert, 2012/10/18
- Re: Lisp object that refers to a C struct,
Eli Zaretskii <=
- Re: Lisp object that refers to a C struct, Juanma Barranquero, 2012/10/18
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/18
- Re: Lisp object that refers to a C struct, Stefan Monnier, 2012/10/18
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/18
- Re: Lisp object that refers to a C struct, Stefan Monnier, 2012/10/18
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/19
- Re: Lisp object that refers to a C struct, Stefan Monnier, 2012/10/19
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/19
- Re: Lisp object that refers to a C struct, Stefan Monnier, 2012/10/19
- Re: Lisp object that refers to a C struct, Eli Zaretskii, 2012/10/19