From: Harold Hausman <hhausman@...>
Date: 2007-03-31T22:08:48+09:00
Subject: Re: How to crash Ruby by not registering global C variable ?

On 3/31/07, 13 <one.three@gmail.com> wrote:
> Hi list,
>
> On page 284 of Pickaxe, 2nd edition there is a passage:
>
> > If you create a Ruby object from C and store it in a C global variable without exporting it to Ruby, you must at least tell the garbage collector about it, lest ye be reaped inadvertently.
>

Your masochistic behavior scares me a little bit ;), but if I
understand your intention correctly, you don't *actually* want to call
rb_define_variable like you do on line 13... I believe calling that
will cause Ruby to reference the string which is typically a good
thing, but in this case it's whats causing you to fail to see the
fireworks that you seek.

Even if Ruby never references your string, and the garbage collector
does 'reap you inadvertently' you probably wouldn't see the fireworks
until you happened to dereference the 'str' variable later in your C
program, and even then only if the memory in question had been filled
with something interesting in the mean time.

Thats the slippery nature of the descrivbd problem, when you do fall
victim to it it might be tough to debug, because all you're going to
have is *occasionally* an 'str' variable filled with something
strange.

Hope that helps,
-Harold