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Date: Sun, 30 Dec 2012 14:08:23 +0100
From: Marek Kubica <marek@xivilization.net>
To: caml-list@inria.fr
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Subject: [Caml-list] C interop: Return values in parameters

Hi,

I am trying to wrap a C library in OCaml but I don't know how to do
this particular thing:

I have a library that looks roughly like this:

int function(void** ptr);

So I get an int as return value to show whether the function succeeded
and it *sets* the ptr.

void* ptr;
function(&ptr);
// ptr is different now

How can I wrap such a function in OCaml? When I call my OCaml wrapper

let retval = function ptr in
    ...

the pointer does not get updated. Is there a function in the C API to
force OCaml to update the values?

regards,
Marek