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,
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