note 89634 added to language.types.object
| From: | edgar dot klerks at gmail dot com | Date: | Tue, 17 Mar 2009 15:04:24 +0000 |
| Subject: | note 89634 added to language.types.object | ||
| Groups: | php.notes | ||
| Request: | Send a blank email to php-notes+get-152046@lists.php.net to get a copy of this message | ||
I saw there was some confusing about what the & operator does in php in relation to objects. So
I made an illustrative example:
<?php
class Test {
}
class Test2 {
}
print "---\n";
/* A normal assignment makes test2 into a reference to the object
result:
---
object(Test)#1 (0) {
}
object(Test2)#2 (0) {
}
*/
$test1 = new Test;
$test2 = $test1;
$test2 = new Test2;;
print var_dump($test1);
print var_dump($test2);
/* If we use & we make test2 a reference to $test1
result:
---
object(Test2)#2 (0) {
}
object(Test2)#2 (0) {
}
try instead $test2 = 'pipo';
*/
print "---\n";
$test1 = new Test;
$test2 =& $test1;
$test2 = new Test2;
print var_dump($test1);
print var_dump($test2);
/* If we want to prevent, we ever overwrite what is in $test1, we can do the following:
$test2 =& new Test2;
I don't understand what happens here exactly.
result:
---
object(Test)#3 (0) {
}
object(Test2)#2 (0) {
}
*/
print "---\n";
$test1 = new Test;
$test2 =& $test1;
$test2 =& new Test2;
print var_dump($test1);
print var_dump($test2);
?>
----
Server IP: 83.137.20.135
Probable Submitter: 92.65.202.85
----
Manual Page -- http://www.php.net/manual/en/language.types.object.php
Edit -- https://master.php.net/note/edit/89634
Del: integrated -- https://master.php.net/note/delete/89634/integrated
Del: useless -- https://master.php.net/note/delete/89634/useless
Del: bad code -- https://master.php.net/note/delete/89634/bad+code
Del: spam -- https://master.php.net/note/delete/89634/spam
Del: non-english -- https://master.php.net/note/delete/89634/non-english
Del: in docs -- https://master.php.net/note/delete/89634/in+docs
Del: other reasons-- https://master.php.net/note/delete/89634
Reject -- https://master.php.net/note/reject/89634
Search -- https://master.php.net/manage/user-notes.php