From: ZaCk <ladacez@...>
Date: 2011-07-03T10:16:29+09:00
Subject: Re: Ruby C API:How to prevent a VALUE being collected by the garbage collecter?

--001636c927bcf9c60504a71fffed
Content-Type: text/plain; charset=ISO-8859-1

Thanks.
Finally I use rb_gc_mark to do this. I am embedding ruby, but the program
collapsed when calling rb_funcall. I debugged it and found out that if GC
occurs during the calling, the arguments would be collected, and the program
throwed a segment fault. I tried rb_gc_mark and rb_gc_force_recycle to
protect the arguments. It worked. Maybe ruby is not suitable for embedding.
Hah...


2011/7/3 Joel VanderWerf <joelvanderwerf@gmail.com>

> On 07/02/2011 11:35 AM, Kim Burgestrand wrote:
>
>>
>> On Saturday, 2 July 2011 at 18:35, Quintus wrote:
>>
>>  Ruby C API:How to prevent a VALUE being collected by the garbage
>>>> collecter? Is there any function to call?
>>>>
>>> If you want it to never be collected, make it a global variable.
>> rb_gc_mark will
>> only do what you want until the next GC cycle.
>>
>
> That's right. Take a look at README.EXT in ruby source, which says:
>
>  GC should know about global variables which refer to Ruby's objects, but
>> are not exported to the Ruby world.  You need to protect them by
>>
>>  void rb_global_variable(VALUE *var)
>>
>
> So if you do this:
>
> VALUE my_global;
> ...
>  rb_global_variable(&my_global)**;
>
> Then whatever object is referenced by my_global when GC runs will not be
> collected.
>
> If you just want to protect some VALUEs that are not necessarily pointed to
> by C variables, you could just keep them in a (ruby) array or other data
> structure, as long as that array is reachable from some variable known to
> ruby.
>
>

--001636c927bcf9c60504a71fffed--