From: Richard Dale <Richard_Dale@...>
Date: 2004-07-30T06:36:45+09:00
Subject: Re: C ext: GC claiming objects early

Sean O'Dell wrote:

> On Thursday 29 July 2004 13:11, Tilman Sauerbeck wrote:
>>
>> I know I can work around this by using rb_global_variable() to tell the
>> GC not to claim the object, but this kinda sucks since the object will
>> never be freed :(
>>
>> So, my question is: how do I prevent the Result object from being
>> claimed by the GC without using rb_global_variable's?
> 
> If this object is a VALUE variable in your C code, you should declare it
> this way:
> 
>     volatile VALUE result = Qnil;
> 
> Adding volatile allows the GC to see the object on the C stack.  This
> means that so long as your C code holds it in that variable, it will never
> go away.
What about using rb_gc_register_address() to ensure the result object isn't
gc'd?

VALUE Result;
....

rb_gc_register_address(&Result);

-- Richard