From: Joel VanderWerf <vjoel@...>
Date: 2006-05-02T04:22:48+09:00
Subject: Re: Shortcut for [string].pack("p*").unpack("l").first ?

Berger, Daniel wrote:
> Hi all,
> 
> If I want to get the underlying pointer address of a
> Ruby string, I can do this:
> 
> string = "hello"
> [string].pack("p*").unpack("l").first # 43329024
> 
> I thought there was a shortcut for this.  Originally I thought
> perhaps object_id was identical, but that doesn't seem to be
> the case.  Maybe that was immediate types only.

Even if you can munge object_id and get a pointer to the object, still,
in the case of strings, you have to dereference from a field in the
object to get to the actual string storage:

struct RString {
    struct RBasic basic;
    long len;
    char *ptr;
    union {
	long capa;
	VALUE shared;
    } aux;
};

-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407