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To: Derick Rethans <derick@php.net>
Cc: internals@lists.php.net
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Date: 10 Mar 2004 12:08:00 -0500
Message-ID: <1078938480.8502.6.camel@blobule.suds>
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Subject: Re: [PHP-DEV] Question about internal workings of
	references/variables.
From: robert@interjinn.com (Robert Cummings)

On Wed, 2004-03-10 at 10:30, Derick Rethans wrote:
> On Wed, 10 Mar 2004, Robert Cummings wrote:
> 
> > Hi Internals,
> >
> > I'd like to confirm/refute some knowledge I think I have of the PHP
> > internal workings with respect to variables and references. I believe
> > that when a variable is assigned the value of another variable an
> > internal reference is created and some bit is used to keep track of
> > whether the value should be copied when an attempt is made to change
> > either the original variable or the newly assigned variable (maybe this
> > isn't the case for integers or floats since the performance would be
> > similar). Can anyone confirm or elaborate further?
> 
> yes, that is true and called "copy-on-write". It's done for all types of
> variables though.
> 
> > Also I think I remember hearing once upon a time that creating a
> > reference in PHP script is more work than creating a copy when the copy
> > won't be altered? Can this be confirmed also?
> 
> Never tried that myself, but I believe it to be true.
> >
> > Last but not least, do objects work under the same principles?
> 
> yes, in php 4 they do. in php 5 it is true for "object-handles" and not
> objects, but that shouldn't be of any concern.

Thanks Derick, now I'll be sure to not misinform others :)

Cheers,
Rob

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