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Subject: Re: [Caml-list] Converting variants with only constant constructors  to integers
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From: Damien Doligez <damien.doligez@inria.fr>
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Date: Mon, 23 Aug 2010 16:36:19 +0200
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References: <4C0D3557.1020200@gmail.com> <010d01cb0672$09f3eb90$1ddbc2b0$@romulus.metastack.com> <4C0D4C88.4070102@gmail.com> <AANLkTinsp9JgePfV6aZVyypOdjNHmNzz3E_i-U3Zvo9S@mail.gmail.com> <AANLkTikI4-YKT7A3AaNoippzvyAZBRU-HlhaGAh6QwrC@mail.gmail.com> <AANLkTimcF7VHWskWk3ZINn_ySH4oxIHFvFP1mXmqtw1x@mail.gmail.com> <AANLkTilJ6R6MPCY7d2E7IcjFzITMIJipHd2yyH-02TfD@mail.gmail.com> <AANLkTikRe85mNn83G8zU6JCQzjj2VkRlQQN1DOy1146q@mail.gmail.com>
To: Kaustuv Chaudhuri <kaustuv.chaudhuri@inria.fr>
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X-Spam: no; 0.00; variants:01 constructors:01 integers:01 damien:01 damien:01 polymorphism:01 ocaml:01 val:01 ocamlrun:01 malloc:01 1.0:98 doligez:01 doligez:01 wrote:01 caml-list:01 

Hi Kaustuv,

On 2010-06-08, at 20:22, Kaustuv Chaudhuri wrote:

>> Of course intify can cause a segmentation fault!
>>=20
>> # let arr =3D Array.of_list [intify 1.0; 0];;
>> Segmentation fault
>=20
> This may be splitting hairs, but the reason that fails is that
> Array.of_list's ad hoc polymorphism heuristic assumes that if the
> first element of the list is allocated, then all elements are
> allocated. Merely changing the order works.


Then again, good old addition has the same kind of problem with
intify.

$ ocaml
        Objective Caml version 3.12.0

# external intify : 'a -> int =3D "%identity";;
external intify : 'a -> int =3D "%identity"
# let x =3D 1 + intify (1, 2);;
val x : int =3D 2147734445
# Gc.minor ();; =20
ocamlrun(11589) malloc: *** mmap(size=3D184834061894270976) failed =
(error code=3D12)
*** error: can't allocate region


-- Damien