From: nobu.nokada@...
Date: 2003-10-09T07:15:50+09:00
Subject: Re: GC and the stack

Hi,

At Thu, 9 Oct 2003 02:27:08 +0900,
Sean O'Dell wrote:
> >>I have heard statements indicating that you need to declare all local VALUEs
> >>volatile, in order to ensure that they are put on the stack by the compiler
> >>and not in a register. Can I get an authoritative answer to this question?
> >>The ruby source code is full of "volatile", but it is not mentioned once
> >>either on the rubygarden.org WIKI or the README.EXT. Why should this be
> >>necessary? Couldn't the garbage collector check the registers too?
> > 
> > Unnecessary, in general.  GC checks the registers of course.
> 
> Actually, he does need to mark them as volatile.  My objects were 
> getting reaped unexpectedly on me because of this.  The Ruby GC might 
> check the registers, but it wasn't finding my objects there, and it was 
> a fantastic waste of many hours scratching my head.

Indeed, you'll need StringValue() or something similar in such
case.  This might prevent it.

  *(volatile VALUE *)&reaped_object;

-- 
Nobu Nakada