PHP: making a copy of a reference variable

If I make a copy of a reference variable. Is the new variable a pointer or does it hold the value of the variable the pointer w开发者_开发百科as referring to?

It holds the value. If you wanted to point, use the & operator to copy another reference:

$a = 'test';
$b = &$a;
$c = &$b;

Let's make a quick test:

<?php

$base = 'hello';
$ref =& $base;
$copy = $ref;

$copy = 'world';

echo $base;

Output is hello, therefore $copy isn't a reference to %base.

Let me murk the water with this example:

$a = array (1,2,3,4);
foreach ($a as &$v) {

}
print_r($a);

foreach ($a as $v) {
  echo $v.PHP_EOL;
}
print_r($a);

Output:

Array
(
   [0] => 1
   [1] => 2
   [2] => 3
   [3] => 4
)

1
2
3
3

Array
(
   [0] => 1
   [1] => 2
   [2] => 3
   [3] => 3
)