#16245 [Com]: Static variables into class member funtions have wrong scope
| From: | gandalf at alladyn dot art dot pl | Date: | Fri, 13 Dec 2002 17:17:35 +0000 |
| Subject: | #16245 [Com]: Static variables into class member funtions have wrong scope | ||
| References: | 1 | Groups: | php.doc |
| Request: | Send a blank email to phpdoc+get-969350288@lists.php.net to get a copy of this message | ||
ID: 16245
Comment by: gandalf@alladyn.art.pl
Reported By: flying@dom.natm.ru
Status: Bogus
Bug Type: Documentation problem
Operating System: Windows 2000 Server
PHP Version: 4.0.6
New Comment:
Hmm... this _is_ a bug. Two instances should have anything common.
class A{
function ble(){
global $x;
static $r=0;
print($r++.'<br>');
$x->ble();
}
}
$x=new A();
$y=new A();
$y->ble();
And we're down...
If it's not a bug than what is this? Proper behaviour?
Previous Comments:
------------------------------------------------------------------------
[2002-06-17 14:34:01] hholzgra@php.net
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at
http://www.php.net/manual/ and the instructions on how to
report
a bug at http://bugs.php.net/how-to-report.php
------------------------------------------------------------------------
[2002-03-24 14:26:07] flying@dom.natm.ru
> I guess this is expected behaviour.
I can't agree with it. If there is two separate instances of a class -
they must have no common variables, but they have.
> Reclassified as a documentation problem.
> (BTW you can use global $cnt to overcome this problem)
No, problem can be solved by having member variable instead of static.
------------------------------------------------------------------------
[2002-03-24 14:22:08] sander@php.net
I guess this is expected behaviour.
Reclassified as a documentation problem.
(BTW you can use global $cnt to overcome this problem)
------------------------------------------------------------------------
[2002-03-24 11:28:51] flying@dom.natm.ru
Static variables inside member functions of a classes have wrong
scope. They should belong to each instance of a class, like normal
class properties, but they're belong to class definition instead and,
therefore, shared between every instance of this class. It makes static
variables unusable into class member variables.
Here is an example:
// Define class
class A
{
var $id = null;
function A($id)
{
$this->id = $id;
}
function func()
{
// Here we have counter into static variable
static $cnt;
if (!$cnt)
$cnt = 0;
// Show counter value and ID of a class instance
echo $this->id.": ".($cnt++)."\n";
}
};
// Create 2 instances of our class with different IDs
$a = new A('A');
$b = new A('B');
// Call method of each class instance twice and see,
// what will happen
$a->func();
$b->func();
$a->func();
$b->func();
Expected results:
-----------------
A: 0
B: 0
A: 1
B: 1
Actual results:
---------------
A: 0
B: 1
A: 2
B: 3
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=16245&edit=1