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... */