From: Eric Hodel <drbrain@...7.net>
Date: 2012-05-18T07:24:33+09:00
Subject: Re: rb_gc_register_address() or rb_gc_mark()?

On May 17, 2012, at 12:31, Hans Mackowiak wrote:
> i create an hash from the C-side, mark them with rb_global_variable and 
> then store my objects into them …
> 
> this protects my objects from being deleted.


This is probably wrong.

By using rb_global_variable the object can never be reclaimed by the garbage collector.

You should either:

Return a ruby object to the user that stores your Hash.

Use Data_Wrap_Struct/Data_Make_Struct to store your Hash and use rb_gc_mark to indicate it is still alive.

Use a constant, class or instance variable on a pre-defined class to store your Hash.