From: Remi VANICAT <vanicat@labri.u-bordeaux.fr>
To: caml-list@inria.fr
Subject: Re: [Caml-list] initializers and destructor
Date: 31 Mar 2002 23:41:23 +0200 [thread overview]
Message-ID: <87n0wo5sak.dlv@wanadoo.fr> (raw)
In-Reply-To: <20020331210924.GA11224@cs.unibo.it>
Stefano Zacchiroli <zack@cs.unibo.it> writes:
> Hi all,
> I know and frequently use "initializer" construct in classes, but I'm
> not able to find something like destructor that works exectly like an
> initializer but that is invoked just before an object last reference is
> lost.
>
> Is this somewhat difficult to implement in relation with the OCaml GC or
> I'm simply missing something?
there is the finalise function in the module Gc of the standard
library.
one can write a destructor using it :
# class foo =
let f x = print_string "test"; print_newline () in
object(s)
initializer
Gc.finalise f s
end;;
class foo : object end
# new foo;;
- : foo = <obj>
# Gc.full_major ();;
test
- : unit = ()
#
but you should know that there is some pitfall with finalise :
# class foo =
object(s)
val bar = "test"
initializer
Gc.finalise (fun x -> print_string bar; print_newline ()) s
end;;
class foo : object end
# new foo;;
- : foo = <obj>
# Gc.full_major ();;
- : unit = ()
# Gc.full_major ();;
- : unit = ()
here, the created object is reachable from the closure of
finalisation, so it's reachable, and never garbage collected.
You should carefully read it's documentation
--
Rémi Vanicat
vanicat@labri.u-bordeaux.fr
http://dept-info.labri.u-bordeaux.fr/~vanicat
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next prev parent reply other threads:[~2002-03-31 22:40 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-03-31 21:09 Stefano Zacchiroli
2002-03-31 21:41 ` Remi VANICAT [this message]
2002-04-01 7:45 ` Stefano Zacchiroli
2002-04-01 10:15 ` Remi VANICAT
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