# Shortcut for .pack("p\*").unpack("l").first?

**URL:** <https://www.ruby-forum.com/t/shortcut-for-pack-p-unpack-l-first/94393>\
**Category:** Ruby\
**Created:** [May 3, 2006, 6:57pm UTC](https://www.ruby-forum.com/t/shortcut-for-pack-p-unpack-l-first/94393 "2006-05-03T18:57:25Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [May 3, 2006, 6:57pm UTC](https://www.ruby-forum.com/t/shortcut-for-pack-p-unpack-l-first/94393/1 "2006-05-03T18:57:25Z")

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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.

Anyway, is there a shorter way? Or am I remembering  
incorrectly?

Thanks,

Dan

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**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [May 3, 2006, 6:57pm UTC](https://www.ruby-forum.com/t/shortcut-for-pack-p-unpack-l-first/94393/2 "2006-05-03T18:57:51Z")

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2006/5/1, Berger, Daniel [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid):

> Hi all,
> 
> If I want to get the underlying pointer address of a  
> Ruby string, I can do this:

What do you want with a memory address in Ruby-land? If you’re in an  
extension then there’s probably an easier way to get at the address.

> 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.

If you want to identify an individual object then of course object\_id  
is the appropriate means.

Kind regards

robert

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<div class="post-metadata">

**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [May 3, 2006, 6:58pm UTC](https://www.ruby-forum.com/t/shortcut-for-pack-p-unpack-l-first/94393/3 "2006-05-03T18:58:04Z")

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Berger, Daniel wrote:

> If I want to get the underlying pointer address of a

Insert standard confusion about someone worried about pointers in Ruby.  
Assume you know what you want.

> Ruby string, I can do this:
> 
> string = “hello”  
> [string].pack(“p\*”).unpack(“l”).first # 43329024
> 
> Anyway, is there a shorter way? Or am I remembering  
> incorrectly?

Why don’t you just add it to String?

irb(main):001:0\> class String; def blah;  
[self].pack(“p\*”).unpack(“l”).first; end; end  
=\> nil  
irb(main):002:0\> “hello”.blah  
=\> 43862144

–Steve

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<div class="post-metadata">

**Author:** ![BergerS\_Daniel](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/b/bc8723/32.png) [@BergerS\_Daniel](https://www.ruby-forum.com/u/BergerS_Daniel)\
**Post date:** [May 3, 2006, 6:58pm UTC](https://www.ruby-forum.com/t/shortcut-for-pack-p-unpack-l-first/94393/4 "2006-05-03T18:58:14Z")

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Berger, Daniel wrote:

> 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;  
};