Re: WIlderness:: Why do strings when created also seem to create a SHARED object (rb_str_new3)

On Aug 26, 2005, at 10:26 PM, Charles E. Thornton wrote:

> While exploring the ELTS_SHARED flag, I  would think the shared  
> object would only be created
> when a string was modified and had more than one reference refering  
> to it.
>
> But it seems that whenever you do this for example
>      a = "content"
>
> This is created:
> OBJ1:  basic.flag |= ELTS_SHARED
>            ptr -> "content"
>            len -> 7
>            aux.shared -> OBJ2
> OBJ2   ptr -> "content"
>            len -> 7
>            aux.capa -> 7
>
> Question: 1) Why do this at the time a string object is created?

This saves having to create a new char array each time the 'a =  
"content"' is executed.  When parsing a shared string is created like  
OBJ1 above.  Each time the statement is executed 'a' is set to  
reference a new string which points to the same char array as OBJ1  
(using rb_str_new3(); note rb_str_new3() only creates one new string  
object).

>                 2) Do Arrays do the same thing?

no, but they do share VALUE arrays.

>                 3) Other Built-in Types do something similar
>                    (they don't seem to use ELTS_SHARED anyway)

I don't think there is an opportunity to do this with any of the  
other built-in types.

-Charlie

>
> -- 
> GodFather -- 667 Neighbor of the Beast
>
>
>