caml-list - the Caml user's mailing list
 help / color / mirror / Atom feed
From: Jianzhou Zhao <jianzhou@seas.upenn.edu>
To: Florent Monnier <monnier.florent@gmail.com>
Cc: caml-list@yquem.inria.fr
Subject: Re: [Caml-list] How to pass C pointers to Caml
Date: Mon, 1 Mar 2010 08:23:16 -0500	[thread overview]
Message-ID: <9dfe358d1003010523x158ba5f4u61999fde49ff7719@mail.gmail.com> (raw)
In-Reply-To: <201003010722.15601.monnier.florent@gmail.com>

On Mon, Mar 1, 2010 at 1:22 AM, Florent Monnier
<monnier.florent@gmail.com> wrote:
> Le lundi 1 mars 2010 04:55:00, Jianzhou Zhao a écrit :
>> I have been calling OCaml code from C in my project.
>> The C code has some pointers to C structures.
>> I got 'seg fault' when calling the OCaml function receiving
>> C structure pointers.
>>
>> 18.7 at http://caml.inria.fr/pub/docs/manual-ocaml/manual032.html
>> gives the examples that pass int into OCaml. These examples work for me.
>> But, Does OCaml support to pass C structure pointers to OCaml?
>
> Yes it does. Just cast your pointer to the type value.
>
> In this tutorial there is an example "Pointers to C structures":
> http://www.linux-nantes.org/~fmonnier/OCaml/ocaml-wrapping-c.php#ref_ptr
>
> the pointer to a C struct is wrapped on the ocaml side by an abstract type
> called "t" here, and it is provided back to C with print_t / dump_ptr.

Thanks. This tutorial helps a lot when calling C from OCaml.
What I was doing is more like calling OCaml from C, at section
http://www.linux-nantes.org/~fmonnier/OCaml/ocaml-wrapping-c.php#ref_mlfromc.
Because my main program is C. In this case, does OCaml have any restriction
when passing a C pointer (which points to a struct) to OCaml runtme in
this direction?

Jianzhou

>
> _______________________________________________
> Caml-list mailing list. Subscription management:
> http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
> Archives: http://caml.inria.fr
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>



-- 
Jianzhou


  reply	other threads:[~2010-03-01 13:23 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-01  3:55 Jianzhou Zhao
2010-03-01  6:22 ` [Caml-list] " Florent Monnier
2010-03-01 13:23   ` Jianzhou Zhao [this message]
2010-03-01 13:24   ` Goswin von Brederlow
2010-03-01 23:04     ` Florent Monnier
2010-03-02 10:19       ` Goswin von Brederlow
2010-03-02 11:34         ` Florent Monnier
2010-03-03 11:02           ` Goswin von Brederlow

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=9dfe358d1003010523x158ba5f4u61999fde49ff7719@mail.gmail.com \
    --to=jianzhou@seas.upenn.edu \
    --cc=caml-list@yquem.inria.fr \
    --cc=monnier.florent@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).