Le 20-12-21 19:37:54, Xavier Leroy a écrit :
> On Sun, Dec 20, 2020 at 8:57 PM <christophe@raffalli.eu> wrote:
>
>     Hello,
>
>     May global roots be initialized to (value)NULL ?
>
>
> Yes, in the default OCaml configuration as of today.
>
> No, in the "no naked pointers" mode that was introduced in OCaml 4.02.0, made
> much stricter in OCaml 4.12.0, and will be the default in OCaml 5.0.
>
> To be future-proof and on the safe side, I would suggest to initialize to e.g.
> Val_unit.
>

Hello,

Thanks for the help.

I took a stronger path and initialized to (fun _ -> assert false).

I added an issue in github for improving the documentation for typing constraints
in the foreign C interface for OCaml.

It seems I have no more segfault (not sure yet as the segfault was no reproductible).
This is strange because I am using 4.11.1+flambda and the documentation says that
using out of heap pointer (i.e. NULL ?) is depreacated for 4.11, but should work?

Christophe

>
>     I have a multithreaded program, which segfault in callback_asm, while I
>     think I respect all rules of c interfaces... Except maybe the above...
>
>
> There is an OPAM compiler switch "4.10.0+nnpcheck" that adds run-time checks
> for ill-formed values according to the no-naked-pointers rules.  Maybe you
> could use it to rule out this potential problem.
>
> Hope this helps,
>
> - Xavier Leroy
>
>
>
>     Chevets,
>     Christophe
>     --
>     Envoyé de mon appareil Android avec Courriel K-9 Mail. Veuillez excuser ma
>     brièveté.
>