Bitwise Operators

Bitwise operators allow you to turn specific bits within an integer on or off. If both the left- and right-hand parameters are strings, the bitwise operator will operate on the characters' ASCII values.

<?php
echo 12 ^ 9; // Outputs '5'

echo "12" ^ "9"; // Outputs the Backspace character (ascii 8)
                 // ('1' (ascii 49)) ^ ('9' (ascii 57)) = #8

echo "hallo" ^ "hello"; // Outputs the ascii values #0 #4 #0 #0 #0
                        // 'a' ^ 'e' = #4
?>

Table 15-3. Bitwise Operators

ExampleNameResult
$a & $bAndBits that are set in both $a and $b are set.
$a | $bOrBits that are set in either $a or $b are set.
$a ^ $bXor Bits that are set in $a or $b but not both are set.
~ $aNot Bits that are set in $a are not set, and vice versa.
$a << $bShift left Shift the bits of $a $b steps to the left (each step means "multiply by two")
$a >> $bShift right Shift the bits of $a $b steps to the right (each step means "divide by two")

Warning

Don't right shift for more than 32 bits on 32 bits systems. Don't left shift in case it results to number longer than 32 bits.

Hosting by: Hurra Communications Ltd.
Generated: 2007-01-26 18:00:28