note 96927 added to functions.arguments
| From: | pigiman at gmail dot com | Date: | Tue, 23 Mar 2010 17:37:11 +0000 |
| Subject: | note 96927 added to functions.arguments | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-167320@lists.php.net to get a copy of this message | ||
Hey,
I started to learn for the Zend Certificate exam a few days ago and I got stuck with one
unanswered-well question.
This is the question:
âAbsent any actual need for choosing one method over the other, does passing arrays by value to
a read-only function reduce performance compared to passing them by reference?â
The answers speaks about Lazy Copy Mechanism\Copy-on-Write.
I tried to search at php.net, zend forums and google.com about how this mechanism works, and
unfortunately there were no results.
I`m trying to understand what is the deference between passing array by value (when readonly) and
passing array by reference, and why passing the array by value is faster?
My example:
function test($array)
{
echo $array[0]." ".$array[1];
}
$arr=array(1,2);
test($array);
because the $array is read-only, the $arr was not copy, right? so where $array point to?
This question answered by Zend support team at Zend.com:
"A copy of the original $array is created within the function scope. Once the function
terminates, the scope is removed and the copy of $array with it." (By massimilianoc)
Hope you'll understand the meaning of Lazy Copy Mechanism\Copy-on-write.
More question can be asked at:
http://forums.zend.com/viewtopic.php?f=63&t=5879&start=0
Have a nice day!
Shaked KO
----
Server IP: 69.147.83.197
Probable Submitter: 93.173.68.0
----
Manual Page -- http://www.php.net/manual/en/functions.arguments.php
Edit -- https://master.php.net/note/edit/96927
Del: integrated -- https://master.php.net/note/delete/96927/integrated
Del: useless -- https://master.php.net/note/delete/96927/useless
Del: bad code -- https://master.php.net/note/delete/96927/bad+code
Del: spam -- https://master.php.net/note/delete/96927/spam
Del: non-english -- https://master.php.net/note/delete/96927/non-english
Del: in docs -- https://master.php.net/note/delete/96927/in+docs
Del: other reasons-- https://master.php.net/note/delete/96927
Reject -- https://master.php.net/note/reject/96927
Search -- https://master.php.net/manage/user-notes.php