Problem with "=& new" and locally created instances
| From: | Jens von Pilgrim | Date: | Fri, 28 Mar 2003 11:07:52 +0000 |
| Subject: | Problem with "=& new" and locally created instances | ||
| Groups: | php.general | ||
| Request: | Send a blank email to php-general+get-141410@lists.php.net to get a copy of this message | ||
Hi,
I've got a problem with the "=& new" construct. A code sample tells more
than 1000 words:
<?php
class foo {}
$g_fooInstance = null;
class factory {
function factory() {
global $g_fooInstance;
if (is_null($g_fooInstance)) {
$g_fooInstance =& new foo(); // <-- here's the problem
// $g_fooInstance = new foo(); // <-- this works
}
}
}
function main() {
$theFactory =& new factory();
global $g_fooInstance;
if (is_null($g_fooInstance)) {
echo ('This isn\'t expected - why is it null?');
} else {
echo ('It works as expected');
}
}
// run
main();
?>
This code is running like that and demonstrates exactly the "weird"
behaviour.
Running this example, the variable $g_fooInstance is null in function
main(). But why? Is the reference to the constructed object descructed after
leaving the scope of function factory::factory()? Or in other words, are
locally created instances always destructed, regardless if there are other
references on the instance?
Is this a bug (the reference mechanism isn't working as expected) - or a
feature (locally created instances are immediately after leaving the scope)?
Maybe I've programmed Java too long...
Regards,
jens