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Date: Wed, 29 Jul 2015 11:27:44 +0200
From: Xavier Leroy <xavier.leroy@inria.fr>
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Subject: Re: [Caml-list] What's the best practice for bindings for c++
 templates?

On 28/07/2015 20:40, Goswin von Brederlow wrote:
> Hi,
> 
> I'm halfway done writing a c++ library for a network protocol and
> considering writing some bindings for ocaml. The library uses
> templates to make objects customizable and am wondering what the best
> practice is there. [...]
> 
> 1) For the stub code I need to instantiate the template with 'a, which
> obviously doesn't work since the C++ stub has no idea about what type
> ocaml will use in the future.
> 
> So do I instantiate it with void *? uintptr_t? value?
> 
> 2) I'm storing ocaml values in C++ structures and getting them back.
> How do I make that play nice with the GC?

My C++ is rusty, but perhaps you could use the "smart pointer" pattern
to equip OCaml's "value" type with appropriate constructors,
destructors and assignment operations ("appropriate" meaning that they
register and unregister the address of the value with the GC as
needed).  Then, you would instantiate your template with this
"smart value" type.  Just an idea.

- Xavier Leroy