ID: 3176
Comment by: sn_ at gmx dot net
Reported By: markj at usn dot nl
Status: Wont Fix
Bug Type: Misbehaving function
Operating System: HPUX/10
PHP Version: 3.0.13
New Comment:
Using the following code I cannot reproduce the bug using php 5.1.2 or
5.2.0
<?php
function toggle_bit ( &$bitfield, $bitvalue )
{
$bitfield ^= $bitvalue;
}
$settings = 4;
toggle_bit($settings, 10);
echo $settings."\n";
Previous Comments:
------------------------------------------------------------------------
[2006-11-16 21:17:35] borg at servernet dot se
Its still in 4.4.3!
We need a fix for this.
------------------------------------------------------------------------
[2005-12-16 10:03:35] nite2quake at yahoo dot co dot uk
I'm currently using PHP5 and I still seem to have this bug effecting my
scripts.
Paul
------------------------------------------------------------------------
[2005-03-30 09:03:12] [EMAIL PROTECTED]
We are sorry, but we can not support PHP 3 related problems anymore.
Momentum is gathering for PHP 5, and we think supporting PHP 3 will
lead to a waste of resources which we want to put into getting PHP 5
ready. Of course PHP 4 will continue to be supported for the
forseeable future.
------------------------------------------------------------------------
[2000-01-11 08:37:45] markj at usn dot nl
Here's the toggle_bit function:
function toggle_bit ( &$bitfield, $bitvalue )
{
$bitfield ^= $bitvalue;
}
------------------------------------------------------------------------
[2000-01-11 07:56:44] markj at usn dot nl
I encountered this with version 4.0b3, but I suspect it to be in other
versions too... i'll check as soon as I can get 3 running somewhere...
I'm currently using PHP4.0b3, and have encountered some inconsistencies
when manipulating
an integer number at the bit level. I use this integer 'settings' to
store up to 30 user-configurable
settings for my application. 0 being that all are turned off.
When I toggle a specific bit (with my own function toggle_bit(
&$bitfield, $bitnr ) (included below))
i get really strange results if I for example do this:
$settings = 0;
toggle_bit( $settings, 1 ) /* This should toggle bit with value 1,
making $settings 1... */
echo $settings /* This will return garbage... */
This gives random results (probably because $settings is signed, the
result always has a
1 as the first bit (when i do bindec), but isn't -1 (two's complement)
When I first 'turn my value into a unsigned int' by or-ing it with 0:
$settings = 0
$newset = ( $settings | 0 )
toggle_bit( $newset, 1 )
echo $newset /* This will return the expected value of 1... */
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=3176&edit=1
