Re: [Caml-list] using modules to wrap c++ classes

[Joel Reymont <joelr1@gmail.com>]

On Fri, May 4, 2012 at 9:43 AM, Goswin von Brederlow <goswin-v-b@web.de> wrote:

> As discussed on irc you need to create your callbacks[] array as ocaml
> block and register that itself as root. That also has the benefit that
> you only have to register a single root instead of 50.

Assuming that I have a class named MyCallbacks with a public member
callbacks of type value, is this correct?

Also, can I use Is_block to check if there's a closure value stored in
the callbacks block before I dispatch to the closure?

    Thanks, Joel

---

// finalizer, stored in custom_operations

void Callbacks_delete(value v)
{
  CAMLparam1(v);
  MyCallbacks* o = Callbacks_val(v);
  caml_remove_global_root(&o->callbacks);
  delete o;
}

CAMLprim value
Callbacks_new()
{
  CAMLparam0();
  CAMLlocal2(v, cbks);
  v = caml_alloc_custom(&ops, sizeof(MyCallbacks*), 0, 1);
  MyCallbacks* o = new MyCallbacks();
  Callbacks_val(v) = o;
  cbks = caml_alloc(NUM_CBKS, 0);
  o->callbacks = cbks;
  caml_register_global_root(&o->callbacks);
  CAMLreturn(v);
}

extern "C" CAMLprim value
Callbacks_set(value self, value cbk)
{
  CAMLparam2(self, cbk);
  MyCallbacks* o = Callbacks_val(self);
  Store_field(o->callbacks, Tag_val(cbk), Field(0, cbk));
  CAMLreturn(Val_unit);
}

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