RE: [PHP] & performance issues

On 17 April 2008 11:57, Bojan Tesanovic advised: > in PHP5 by default Objects are passed by reference Please stop repeating this -- erm -- inexactitude. In PHP5, objects are passed around by their handle, *not* as a reference. Most of the time, this has the same effect, as you are addressing the same object either way. However, the behaviour of a copied object handle is not the same as a reference. In fact, when you create a reference to an object, what you're actually getting is a reference to the object's handle! To prove this, try running the test code below -- the object handling will not, I assure you, behave as though you were passing a reference around by default, but is directly comparable to the following string example: <?php class test { public $me; } $t = new test; $t->me = 'Original'; $copy_t = $t; $ref_t = &$t; $copy_t = new test; $copy_t->me = 'Altered Copy'; echo <<<RESULT1 Original: $t->me<br /> Copy: $copy_t->me<br /> Reference: $ref_t->me<br /> RESULT1; $ref_t = new test; $ref_t->me = 'Altered Reference'; echo <<<RESULT2 <br /> Original: $t->me<br /> Copy: $copy_t->me<br /> Reference: $ref_t->me<br /> RESULT2; $s = 'String'; $copy_s = $s; $ref_s = &$s; $copy_s = 'String Copy'; echo <<<RESULT3 <br /> Original: $s<br /> Copy: $copy_s<br /> Reference: $ref_s<br /> RESULT3; $ref_s = 'String Reference'; echo <<<RESULT4 <br /> Original: $s<br /> Copy: $copy_s<br /> Reference: $ref_s<br /> RESULT4; ?> Cheers! -- Mike Ford, Electronic Information Services Adviser, JG125, The Headingley Library, James Graham Building, Leeds Metropolitan University, Headingley Campus, LEEDS, LS6 3QS, United Kingdom Email: m.ford@leedsmet.ac.uk Tel: +44 113 812 4730 Fax: +44 113 812 3211 To view the terms under which this email is distributed, please go to http://disclaimer.leedsmet.ac.uk/email.htm