From: Xavier Noria <fxn@...>
Date: 2010-10-03T08:59:23+09:00
Subject: Re: Pass by reference and copy on write

On Sun, Oct 3, 2010 at 1:41 AM, Ralph Shnelvar <ralphs@dos32.com> wrote:

> I see
>  http://www.ruby-forum.com/topic/41160
>
> which has a fairly long explanation of passing stuff by reference and copy on write(cow).

A very noisy thread.


> Let's say I have
>  def som_func(x,y)
>   x = 24
>   y = 42
>  end
>  .
>  .
>
>  a=1
>  b=2
>  .
>  .
>  .
>  some_func(a,b)
>
>
> and I want to have some_func change a to 24 and b to 42 ...
>
> How do I do it?


You can't. Ruby, C, and Java are pass-by-value. With that method call
semantics what you ask is not possible. You certainly can change the
state of a mutable object, but that is unrelated.

Perl is pass-by-reference, you can do that in Perl.

This is jargon, the word "reference" in "pass-by-reference" has
nothing to do with the "references" that Java or Ruby manage. Same
term, different meanings.