From: matz@... (Yukihiro Matsumoto)
Date: 2003-07-04T16:25:21+09:00
Subject: Re: rb_gc_mark(): unknown data type...non object

Hi,

In message "Re: rb_gc_mark(): unknown data type...non object"
    on 03/07/04, Jim Cain <list@jimcain.us> writes:

|In the meantime, I was reading some previous posts about rb_obj_alloc 
|"only working for T_OBJECT classes" in 1.6.x. Just what exactly are 
|T_OBJECT classes? Non-builtin classes? I wasn't sure just what was meant 
|by that, and I do use rb_obj_alloc in a few cases, so out of curiosity I 
|built my extension on 1.8, and now I don't get the gc "unknown data 
|type" error. At least not yet. Maybe just a coincidence. We'll see.

Each object has its "type".  "type" is not a class.  It describes the
structure that object has.  For example an object with T_OBJECT type
is implemented by "struct RObject".  In 1.6.8, classes does not have
information about the type of its instances, so that rb_obj_alloc()
produces T_OBJECT object, no matter what type it should be.  In 1.8.0
each type knows its instance type, so that rb_obj_alloc() work fine
with all classes.  But you have to define allocation function using
new rb_define_alloc_func() API.


							matz.