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From: Damien Doligez <damien.doligez@inria.fr>
To: Paolo Donadeo <p.donadeo@gmail.com>
Cc: OCaml mailing list <caml-list@yquem.inria.fr>,
	OCaml-Lua devel ML <ocaml-lua-devel@lists.forge.ocamlcore.org>
Subject: Re: [Caml-list] C binding and GC interaction: storing values outside the heap
Date: Wed, 8 Sep 2010 00:53:39 +0200	[thread overview]
Message-ID: <8DF23B0B-D2D5-45CE-99B1-37EA0C8BD4C6@inria.fr> (raw)
In-Reply-To: <AANLkTi=VCN4+wpKYG_EWUNX5zsBAs5_G_1hb2Y3uJDsu@mail.gmail.com>


On 2010-09-07, at 22:58, Paolo Donadeo wrote:

> The problem is that, for several good reasons, I need a copy, or a reference, to the OCaml value representing the lua_State (v_L in the code above) inside the Lua state (I mean the C data structure).

That creates a cross-heap reference loop and it's very bad news for the GC.

> As a temporary workaround I removed the "value state_value" field from the ocaml_data struct, replacing it with a reference counter:

Maybe you could try something similar, with a weak hash table to recover the
OCaml value corresponding to a given lua_State, thus eliminating the need for
a reference counter.  Use the address of the lua_State for hashing and for
comparison.

Drawback: the weak hash table has to be global.

-- Damien


  parent reply	other threads:[~2010-09-07 22:53 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-07 20:58 Paolo Donadeo
2010-09-07 21:12 ` [Caml-list] " Stéphane Glondu
2010-09-07 21:23   ` Paolo Donadeo
2010-09-07 21:48     ` Stéphane Glondu
2010-09-09  8:11       ` Paolo Donadeo
2010-09-07 22:53 ` Damien Doligez [this message]
2010-09-09  8:16   ` Paolo Donadeo
2010-09-08  5:06 ` Romain Beauxis

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