[ruby-core:19059] Ruby class name from C extensions

Hi -

If I have ruby source that looks like this:

class Test
  def ....
end

and in a ruby C extension I have something like:

fprintf(stderr, "class name: %s\n", 
RSTRING(rb_class_path(obj->as.basic.klass))->ptr);

I get output like this:

class name: #<Class:0xb7e1158> Why doesn't it output something like: 
#<Test:0x...> ? 

There are two possibilities: either I am not using the correct obj 
struct or I am misusing/misunderstanding rb_class_path().

I am fairly certain I am using the correct struct, so I am probably 
misunderstanding how rb_class_path and related functions work -- is 
there a function I can call that if I pass in a klass or a VALUE it will 
return either a c string or an RSTRING that contains the class name?

Any other hints or advice is greatly appreciated.

Thanks,
Joe