What do the '&=' and '=&' operators do?

Question

Finding the answer to this is turning out to be much more difficult than I would have thought. Since I don\'t have a clue what you\'d call this, it\'s hard to run a Google s

Answer 1

=& is assigning by reference.

It assigns a variable not by value but by reference.

Example:

$a = 'foo';
$b =& $a;

$b = 'bar';

echo $a;

prints bar because $b has a reference to $a and therefore changing $b also changes the value of $a.

---

&= is bitwise AND.

Example:

$a = 4 // binary representation: 100
$b = 1 // binary representation: 001

Then $a &= $b is just short for $a = $a & $b and means: Take every bit and perform the AND operation, that is:

0 & 1 = 0
1 & 0 = 0
1 & 1 = 1
0 & 0 = 0

Therefore

     1 0 0 
AND  0 0 1
     -----
     0 0 0

=> $a = 0 // bit representation 0 ;)