From: Robert Klemme <shortcutter@...>
Date: 2010-11-16T19:27:12+09:00
Subject: Re: Embedding ruby interpreter

On Tue, Nov 16, 2010 at 11:24 AM, Steve Hart <steve@rtsw.co.uk> wrote:
> Hi
> We are looking at upgrading our current version of ruby 1.8.7 to latest
> 1.9.2-p0, We have been running ruby embedded within a pthread with a
> swigged up interface for about 7 years and it has worked fine. On
> changing to 1.9 we get a crash on initialistaiion the first time the gc
> is called.
> This occurs in mark_current_machine_context
>
> Under 1.8.7 we initialised the ruby thread thus
>
> int ScriptThread::run()
> {
>        int    addr;
>        ruby_init();
>        Init_stack((void *)&addr);
>        ruby_script("embedded");
>        ruby_init_loadpath();
>        Init_gm();                     // swigged up interface
>        .....
> }
>
> Under 1.9 I changed this to:
>
> RUBY_GLOBAL_SETUP
>
> int ScriptThread::run()
> {
>        //ruby_sysinit(&argc, &argv); // commented out, no args
> available
>        {
>                RUBY_INIT_STACK;
>                ruby_init();
>        }
>        Init_gm();
>        .....
> }
> Note that our thread is created thru QT using pthreads. We also compile
> 1.8.7 without pthread support. Our interpreter runs exclusively in this
> thread and all VALUE's created in C are properly wrapped and marked.

This is no longer true with 1.9.  1.9 uses native threads (although
there's still the GIL which slows it somewhat down).  I do not know
how best to interact but I guess you could find hints by looking at
thread creation code.

> I have read the threads from
> http://www.ruby-forum.com/topic/144747
> http://redmine.ruby-lang.org/issues/show/2294
> From these it would appear that
>
> a) The ruby initialisation must be done in main
> Is this a change from 1.8.7? What if we are dynamically loaded and have
> no access to main?
> b) The thread should be created using rb_thread_create
> Is this true? If so, why?
> c) disabling pthread support when compiling ruby has been deprecated.
> What does this mean? - Does ruby use threads itself?

See above.

> I briefly tried to disable the gc and then got a crash
> d) Should we apply the patch from 2294?
>
> What is the correct way to do this?
> I would greatly appreciate any help anyone could give.

Others can certainly give more detailed advice but my quick heads up
might send you in the right direction.

Kind regards

robert

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