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