From: Robert Klemme <shortcutter@...>
Date: 2013-04-08T17:37:13+09:00
Subject: Re: Mapping string data ptr to buffer in ffi

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On Mon, Apr 8, 2013 at 4:06 AM, se gm <lists@ruby-forum.com> wrote:

> I'm trying to implement some "shared memory" in Ruby, but I'm not sure
> how to declare it properly with ffi. The idea is to map the read-only
> (in Ruby) string contents(by passing a data ptr) to external C library
> threads so that they would write some data to it. Could you point out
> the proper way to do it ?
>

I think a better way would be to implement a Ruby class in C and provide
the information via a getter method which returns a new Ruby String and
internally uses proper synchronization to maintain thread safety.
 Otherwise if you update the String contents from arbitrary threads you
will create all sorts of race conditions and issues which are hard to hunt
down.

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

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<div dir=3D"ltr"><br><div class=3D"gmail_extra"><br><br><div class=3D"gmail=
_quote">On Mon, Apr 8, 2013 at 4:06 AM, se gm <span dir=3D"ltr">&lt;<a href=
=3D"mailto:lists@ruby-forum.com" target=3D"_blank">lists@ruby-forum.com</a>=
&gt;</span> wrote:<br>
<blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1p=
x #ccc solid;padding-left:1ex">I&#39;m trying to implement some &quot;share=
d memory&quot; in Ruby, but I&#39;m not sure<br>
how to declare it properly with ffi. The idea is to map the read-only<br>
(in Ruby) string contents(by passing a data ptr) to external C library<br>
threads so that they would write some data to it. Could you point out<br>
the proper way to do it ?=A0<br></blockquote></div><div class=3D"gmail_extr=
a"><br></div>I think a better way would be to implement a Ruby class in C a=
nd provide the information via a getter method which returns a new Ruby Str=
ing and internally uses proper synchronization to maintain thread safety. =
=A0Otherwise if you update the String contents from arbitrary threads you w=
ill create all sorts of race conditions and issues which are hard to hunt d=
own.<br>
<br>Kind regards</div><div class=3D"gmail_extra"><br></div><div class=3D"gm=
ail_extra">robert<br clear=3D"all"><div><br></div>-- <br>remember.guy do |a=
s, often| as.you_can - without end<br><a href=3D"http://blog.rubybestpracti=
ces.com/">http://blog.rubybestpractices.com/</a>
</div></div>

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