From: Andres Salomon <dilinger@...>
Date: 2004-10-18T15:54:24+09:00
Subject: calling define_finalizer from within C?

Hi,

I've got the following bit of C code;
   static VALUE do_destroy(...) { ...; return Qnil; }

   cObjectSpace = rb_const_get(rb_cObject, rb_intern("ObjectSpace"));
   rb_include_module(cFoo, cObjectSpace);
   
   /* ... somewhere inside constructor... */
   p = rb_proc_new(do_destroy, obj);
   fprintf(stderr, "created new proc; class %s\n", rb_obj_classname(p));
   rb_funcall(obj, rb_intern("define_finalizer"), 1, p);

Basically, I need to define a finalizer from within a constructor, but I'm
running into the following problems:

1) define_finalizer throws an exception: 
ArgumentError: tried to create Proc object without a block
I'm not sure what would cause that.  The proc object should have a block..

2) At least in irb, calling define_finalizer within a class, and passing
it self as the first arg, causes nothing to happen.  Is define_finalizer
the proper way to do this sort of thing, or is there a better way?  Note
that I don't want to use Data_Make_Struct's free callback, as I need this
to be overridable by users of the class.