From: ptkwt@... (Phil Tomson)
Date: 2005-07-26T04:40:59+09:00
Subject: Re: Ruby and threads (Sydney)

In article <51266.66.192.236.118.1122291266.squirrel@devsea.com>,
John Wells <lists@sourceillustrated.com> wrote:
>Guys,
>
>Was looking through the forums at ruby-ide.com when I noticed the
>following comment:
>
>"Unfortunately i can't use ruby for scripting/extending/implementing as
>ruby does not work with multiple native threads and i already have one
>ruby thread that is doing the background parsing."
>
>Can anyone elaborate on this?  How does it effect folks developing in
>Ruby, and curiously, why does Python seem to support it and Ruby doesn't?
>

It's because there are a lot of globals defined in the Ruby interpreter so 
it's not threadable (native threadable, that is).

However, recently there have been some interesting developments with an 
experimental Ruby interpreter called Sydney.  Here's a quote from the 
weblog page where it was announced:

 "Sydney is an experimental fork of 1.8.2 that adds a number of features, 
 such as:

    * Native OS Threads (Thread::OS). These do not replace the normal 
 Threads, and allow for MxN thread setups (see 
 test/sydney/test_osthread.rb#test_mxn). There is a lot to be said about 
 these, so lets move on for now.
 ...

 In getting OS threads implement, the core of the interpretter has been 
 modified to be reentrant and thread-safe, allowing mulitple threads to 
 run concurrently.

 All globals have been cleaned up and moved into a unified ruby_state 
 struct (accessable directly in the form of Ruby::State objects). "

This way you can get the best of both worlds - Ruby's current 
cross-platform 'green' threads and native threads if you need them.  I 
hope that this makes it back into the 'official' Ruby interpreter.



Phil