Rb_gc_mark(): unknown data type...non object

ruby-talk
1

I figure I’m getting this because I’ve got a VALUE that’s not a Ruby
object. Has anyone figured out a good way to track down such a bug?

2

Hi,

···

In message “rb_gc_mark(): unknown data type…non object” on 03/07/04, Jim Cain list@jimcain.us writes:

I figure I’m getting this because I’ve got a VALUE that’s not a Ruby
object. Has anyone figured out a good way to track down such a bug?

I use gdb. If you’re not using your own extension, show us the
backtrace (output from gdb “where” command). We may be able to help
you.

						matz.
3

Yukihiro Matsumoto wrote:

Hi,

I figure I’m getting this because I’ve got a VALUE that’s not a Ruby
object. Has anyone figured out a good way to track down such a bug?

I use gdb. If you’re not using your own extension, show us the
backtrace (output from gdb “where” command). We may be able to help
you.

  					matz.

Thanks; it’s my Ruby9i extension. I’ve wasted two days on this and
haven’t found anything definitive. Even when I would explicitly start
the gc, sometimes I would get the error and sometimes not. I began to
suspect that it wasn’t a bad VALUE but rather a buffer overrun elsewhere
that was corrupting a VALUE.

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.

···

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

4

Hi,

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.
···

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