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From: Basile STARYNKEVITCH <basile@starynkevitch.net>
To: Julien Cristau <julien.cristau@ens-lyon.fr>
Cc: caml-list@inria.fr
Subject: Re: [Caml-list] mmap() and strings
Date: Wed, 8 Dec 2004 21:24:28 +0100	[thread overview]
Message-ID: <20041208202428.GA9878@ours.starynkevitch.net> (raw)
In-Reply-To: <20041208200458.GC1840@ens-lyon.fr>

Le Wed, Dec 08, 2004 at 09:04:59PM +0100, Julien Cristau écrivait/wrote:
> Hello list,
> 
> I'm wondering if somebody has an idea for the following problem:
> 
> I'm working on a program which manipulates a buffer. A writer process 
> regularly changes this buffer, and reader processes have to work on it 
> after each change. Currently, the buffer is a string and is passed to 
> the readers trough pipes. However, this is costly because the buffer is 
> copied many times at each iteration.

Actually, pipes perform quite well on Linux....

> We thought we could use mmap(2), 
> but there seems to be no easy solution 
> to mmap() a memory region and treat it as a string in ocaml. 

Use Bigarray-s for that. They can mmap files (on Unix & Linux) and are
already in Ocaml 3.08

You might also use IPC shared memory segments, but there is no support
in Ocaml for these (shmget & related system calls), so you'll probably
need to code the C stub (for the Ocaml binding) yourself.

Maybe you'll need JoCaml... (but I don't know if it is dead or not -
it was designed for coding cooperative programs communicating thru
channels).


-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/ 
email: basile<at>starynkevitch<dot>net 
aliases: basile<at>tunes<dot>org = bstarynk<at>nerim<dot>net
8, rue de la Faïencerie, 92340 Bourg La Reine, France


  reply	other threads:[~2004-12-08 20:24 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-12-08 20:04 Julien Cristau
2004-12-08 20:24 ` Basile STARYNKEVITCH [this message]
2004-12-08 20:50   ` [Caml-list] " Julien Cristau
2004-12-09  1:09     ` Jacques Garrigue
2004-12-09  1:42       ` Jacques Garrigue
2004-12-09 10:32         ` David Baelde

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