Rasmus,
Peter and I were discussing the use of ".$myvar." vs "quoted string {$myvar}
more quoted string" in a separate thread.
Is there a performance or compatibility advantage to using the concatenated
version as you suggest in your message below?
I currently use the concatenated version in all of my scripts, but Peter
suggested the curly braces as a way to make the code more readable. While I
agree that the curly brace method IS more readable, I want to know what the
difference is before changing coding conventions.
Thanks,
Rich
> -----Original Message-----
> From: Rasmus Lerdorf [mailto:rasmus@php.net]
> Sent: Sunday, November 17, 2002 12:21 AM
> To: Peter Beckman
> Cc: php-db@lists.php.net
> Subject: Re: Passing by reference
>
>
> PHP uses copy-on-write for by-value passes. So, if you are
> not changing
> the passed string inside the function there is no copy done on a
> pass-by-value and this is actually faster than doing a
> pass-by-reference.
>
> But, I'd suggest doing ".$myvar." (ie. break out of the
> quoted string and
> concat the var.)
>
> -Rasmus
>
> On Sun, 17 Nov 2002, Peter Beckman wrote:
>
> > I'm building some software that will be passing a string
> variable which
> > could potentially be up to 125K bytes (characters) in size.
> >
> > I know that passing a reference to the variable will be
> much more efficient
> > than copying the variable:
> >
> > copying, as I understand it:
> >
> > foo($var)
> > [...later...]
> > function foo ($myvar) { $sql = "insert into table
> (this) values (\"$myvar\")"; }
> >
> > passing by reference, not copying:
> > foo($var)
> > [...later...]
> > function foo (&$myvar) { $sql = "insert into table
> (this) values (\"$myvar\")"; }
> >
> > A few questions:
> > 1. Am I correct that PHP makes a copy of the variable
> when I call the
> > function with the variable, since the scope will not
> be global in
> > the function (unless I declare it such)?
> > 2. Will I be saving some CPU cycles and memory by
> passing by reference?
> > 3. Is my pseudo code above correct? If not, can you
> show me how one
> > might pass by reference correctly?
> >
> > I've tested both pieces of code, but can't determine if there is a
> > speed/memory difference, and I don't actually have 125K in
> data handy!
> >
> > Thanks,
> > Peter
> >
> --------------------------------------------------------------
> -------------
> > Peter Beckman Systems Engineer, Fairfax Cable
> Access Corporation
> > beckman@purplecow.com
> http://www.purplecow.com/
> >
> --------------------------------------------------------------
> -------------
> >
> >
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