#20673 [Ver]: Inexplicable arithmetical error due to references
| From: | sesser@php.net | Date: | Fri, 29 Nov 2002 19:11:43 +0000 |
| Subject: | #20673 [Ver]: Inexplicable arithmetical error due to references | ||
| References: | 1 | Groups: | php.bugs |
| Request: | Send a blank email to php-bugs+get-26200@lists.php.net to get a copy of this message | ||
ID: 20673
Updated by: sesser@php.net
Reported By: dakota@dir.bg
Status: Verified
Bug Type: Scripting Engine problem
Operating System: Win 2000 NT/Linux
PHP Version: 4.3.0-dev/4.4.0-dev
New Comment:
never write something like $a = $a + $a++;
if you f.e. try such a construct in C you will get different
results depending on the compiler and/or optimisation level.
Previous Comments:
------------------------------------------------------------------------
[2002-11-27 07:04:52] dakota@dir.bg
<?
$a = 7;
$a = $a + $a++;
echo $a;
//the result is 14;
?>
When I add a reference to $a, the behavior of $a + $a++ becomes
inexplicable different. Note that $a isn't changed anywhere!
<?
$a = 7;
$b =& $a;
$a = $a + $a++;
echo $a;
//the result is 15;
?>
The only difference is $b =& $a, but why $a takes care of references to
itself?
------------------------------------------------------------------------
--
Edit this bug report at http://bugs.php.net/?id=20673&edit=1