[ruby-core:24854] embedding ruby 1.9 frustration

Hello,
I've been struggling for a long time now, reading the sources,
documentation and mostly README.ext (which seems a bit out of date).
Anyway, I'm having some problems that so far have no answer. I'm using
svn trunk, trying to embed a ruby1.9 interpreter into a C application.
If the application follows a simple "one line" path, everything works
just fine, but if the C app calls some ruby code, and the calling was
triggered by an interrupt (an event, like a click, timer, etc), things
can go wrong, most of the time with a bad access exception right here:


#file vm_method.c; Line 250
NODE *
rb_get_method_body(VALUE klass, ID id, ID *idp)
{
    NODE *volatile fbody, *body;
    NODE *method;

    if ((fbody = search_method(klass, id, 0)) == 0 || !fbody->nd_body) {
...

The exception is raised always on the if.
The backtrace is usually like this:

#0  0x00179714 in rb_get_method_body (klass=22988952, id=366, idp=0x0)
at vm_method.c:256
#1  0x001798b3 in rb_method_node (klass=22988952, id=366) at vm_method.c:301
#2  0x0017ab2b in rb_method_basic_definition_p (klass=22988952,
id=366) at vm_method.c:1057
#3  0x0017ab83 in rb_obj_respond_to (obj=22988980, id=15424, priv=0)
at vm_method.c:1068
#4  0x0017ac34 in rb_respond_to (obj=22988980, id=15424) at vm_method.c:1084
#5  0x000155f1 in sc_funcall (args=0x10f7ad0) at
/Users/rolando/Documents/GFF/ShinyCocos/Integration/SC_init.m:74
#6  0x000609f7 in rb_protect (proc=0x155cb <sc_funcall>,
data=17791696, state=0xbfffe53c) at
/Users/rolando/Documents/GFF/ShinyCocos/ruby/eval.c:648
#7  0x00015726 in sc_protect_funcall (recv=22988980, mid=15424, n=1)
at /Users/rolando/Documents/GFF/ShinyCocos/Integration/SC_init.m:105

Regarding the ruby interpreter, this is what I'm doing to initialize/start it:

	sc_argc = 2;
	sc_argv = (char **)malloc(sizeof(char *) * 2);
	sc_argv[0] = "ShinyCocos";
	sc_argv[1] = (char *)[entryPoint cStringUsingEncoding:NSUTF8StringEncoding];
	
	ruby_sysinit(&sc_argc, &sc_argv);
	{
	RUBY_INIT_STACK;
	ruby_init();
	}
	...
	ruby_script("main.rb");
	rb_protect(RUBY_METHOD_FUNC(rb_require), (VALUE)"main", &state);

main.rb has code in it: starts the Cocos2D-iphone framework (something
like gosu)
And to call the ruby world from a C callback (which is triggered by
the framework), This is what I'm doing:

	struct rb_blocking_region_buffer *region = rb_thread_blocking_region_begin();
	sc_protect_funcall((VALUE)userData, id_sc_on_enter, 0, 0);
	rb_thread_blocking_region_end(region);

sc_protect_funcall is just like rb_funcall, but the call is rb_protected.
What I'm not doing, but I think I should (just don't know where to put
it) is a call to ruby_run.

I'm getting really frustrated, because there's almost no documentation
on how to embed ruby 1.9, and how to treat code that might call the VM
on an async way (some calls to rb_funcall might be called when there's
already some ruby code running, I'm thinking that might be the problem
here). I thought that adding rb_thread_blocking_region_begin/end() was
the solution, but I'm still getting random crashes...
Any pointer on how to do it The Right Way(tm)?

Thanks a lot,
-- 
Rolando Abarca
http://rolando.cl