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Date: -- (:)
From: Jianzhou Zhao <jianzhou@s...>
Subject: Re: [Caml-list] How to pass C pointers to Caml
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

>
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-- 
Jianzhou